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May 14, 2018 - The public spaces selected for this study are Plaza de Armas, Paseo Peatonal .... project sponsored by the local government. .... The meteorological micro-station is installed in a courtyard inside the Biobío university (Campus.
atmosphere Article

Microclimate Metrics Linked to the Use and Perception of Public Spaces: The Case of Chillán City, Chile Pamela Smith 1,2, * 1 2 3

*

ID

and Cristián Henríquez 2,3

Departamento de Geografía, Universidad de Chile, Portugal 84, Santiago Centro, Santiago 8331051, Chile Instituto de Geografía, Pontificia Universidad Católica de Chile; Vicuña Mackenna 4860, Macul, Santiago 7820436, Chile; [email protected] Associate research CEDEUS & Centro de Cambio Global UC, Santiago 7820436, Chile Correspondence: [email protected]

Received: 22 March 2018; Accepted: 7 May 2018; Published: 14 May 2018

 

Abstract: This paper presents research carried out in the city of Chillán, a medium size city located on the southern limit of the Chilean Mediterranean domain, at 36◦ 360 s south latitude. Chillán provides a good representative example of warm summers in central and southern Chilean cities. Five public spaces were selected, representing different typologies and relating to different urban background conditions. Users in these public spaces were observed, counted and photographed five times a day (12, 14, 16, 18 and 20 h, local time) during a heat wave event in the summer of 2016, while meteorological parameters were measured at different points within the public space. The variables evaluated were impervious surfaces, sky view factor, H/W, azimuth, shadow, and radiation. Local public environmental management should pay attention to the complex relations between urban climate, public spaces and thermal comfort since they affect the quality of life of the most vulnerable sectors of the population. This is particularly important given the increasing episodes of elevated temperatures and intense heat waves which have occurred in the city of Chillán in recent summers, which are related to urban heat islands and climate change. Keywords: thermal comfort; green spaces; South American city; urban morphology; climate perception

1. Introduction Public spaces are significant for the habitability and quality of urban life. Many movements, interactions, contacts, interpersonal relations and diverse activities occur within these spaces. The latter characterizes the functioning and essence of the city [1]. The environmental conditions of public spaces depend on various factors that include regional and local climate parameters (such as latitude, average altitude, continentality, orography, size of the city). At the same time, these factors are modified by the morphological components of the urban environment under the urban canopy layer (UCL), resulting in specific microclimatic conditions [2,3]. Among these parameters are the vegetal cover, impervious surfaces, sky view factor, orientation, and the height-width ratio (H/W). These factors define thermal comfort conditions and, consequently, the use of public spaces. Urban microclimate is defined as the climate of a specific area where people live, act and suffer the effects of the city’s problems [4], experiencing rapid changes in time and distance, which results from the heterogeneity of the UCL. At this scale, the urban climate may change abruptly within a very short distance, because of the land use (for example residential, industrial, among others), proportion of built space, thermic quality of materials (color and construction material), orientation and slope of the

Atmosphere 2018, 9, 186; doi:10.3390/atmos9050186

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surface, vegetal cover, ground humidity, among other factors [2]. At the microscale level, individual buildings and trees project their shadow and change wind direction; texturized wall coverings affect sunlight reflection and radiant temperatures to which people are exposed [5]. Most microclimatic studies refer to urban canyons, describing their relationship with building design, particularly with respect to height–width ratio and sky view factor. At the same time, thermal comfort in public spaces has attracted scientific attention. The first studies about thermal comfort were focused on instrumental methods, using equations that incorporate objective parameters (temperature and relative humidity of the air, wind or solar radiation). Later on, the studies included user’s degree of satisfaction with local climatic conditions for obtaining thermal comfort [6–12]. In recent years, research related to other public spaces such as parks, squares, riverside, beaches, etc. has increased significantly. Even though the urbanization process has been intense in Latin America, microclimatic studies are scarce. A study developed in the city of Buenos Aires, Argentina determined that microclimate differences inside the urban areas depend on height and density of buildings, orientation, and width of streets and presence of parks and trees [13]. Ugeda [14] found that in the city of Jales in Brazil, the northern built slope was always warmer than the southern one. In her study, she also discovered a relationship between uncovered ground and heat and highlighted the importance of rainfall in previous years, because it affects ground humidity and, consequently, vegetation coverage. A microclimatological perspective is relevant for the city of Chillán, located in central Chile, which presents very high summer temperatures. In the summer 2016–2017, for example, the city registered a maximum temperature of 41.5 ◦ C. Furthermore, like many other cities in Chile, green areas and public spaces are significantly scarce. There are no studies of urban microclimate for the city of Chillán. This research aims to analyze the morphological conditions of five representative public spaces inside the city to evaluate their impact on microclimate and user’s thermal comfort. 2. Materials and Method Chillán is the capital city of the Ñuble region (recently created in September 2017). It is located at 36◦ 36’ south latitude. Its average altitude is 124 m above sea level (Figure 1). Chillán has a warm temperate climate with winter rains (Cwb), according to the Köppen classification for Chile [15]. The average annual temperature (13.7 ◦ C) corresponds to its latitude. However, its average summer temperature (19.4 ◦ C) and the average of summer maximums (28.4 ◦ C) are similar to those of Arica and Iquique, two cities located in the northern regions of the country. Chillán has 204,180 inhabitants. According to the classification of the Ministry of Housing and Urbanism, it is a medium-size city. There are few green areas within the urban surface (1.7 square meters per inhabitant). It is under the national average (four square meters per inhabitant). The minimum standard recommended by the World Health Organization (WHO) is nine square meters per inhabitant. The public spaces selected for this study are Plaza de Armas, Paseo Peatonal Arauco, Parque Estero Las Toscas, Parque Sarita Gajardo and Parque Monumental Bernardo O’Higgins. This study uses a mixed method perspective, which combines quantitative and qualitative methods and data. Quantitative data were obtained by processing satellite images from SENTINEL 2 (5 March 2016) and field data gathering (January and February 2016) through observation and instrumental measurement of climatic and urban variables. Qualitative data comes from a survey administered to selected public spaces users. The analysis of the urban microclimate considers atmospheric temperature and relative humidity, measured every 10 min. For the above, they used 10 Logtag HAXO-8 (accuracy: 0.1 ◦ C and 0.1% for humidity) and 32 Ibutton Thermochron (accuracy: 0.5 ◦ C) recorders installed in various locations inside the public spaces selected or in their proximities. These parameters were also measured every hour, by meteorological micro-station HOBO data logger RX-3,000, located in the University of Biobío, 800 m west from Parque Estero Las Toscas. This station also registers wind speed and direction as well as global solar radiation (photos in Figure 2 and location in Figure 1).

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Figure 1. Study area. Figure 1. Study area. Figure 1. Study area.

Figure 2. Meteorological instrument installations. Note: (a) Logtag recorder; (b) Logtag recorder Figure 2. 2.Meteorological Note: Logtagmicro-station recorder; Logtag recorder Figure Meteorological instrument installations. Note: (a)(a)Logtag recorder; (b)(b) Logtag recorder installation in the box; (c)instrument Ibutton datainstallations. logger; and (d) meteorological HOBO. installation (d) meteorological meteorologicalmicro-station micro-stationHOBO. HOBO. installationininthe thebox; box;(c) (c)Ibutton Ibuttondata data logger; logger; and (d)

The solar radiation was calculated in Ecotect software from a 3D model of buildings and trees The solar radiation wascalculated calculatedinparameters inEcotect Ecotectsoftware software fromaradiation a3D 3Dmodel model buildings and treesfor forThe each public space. was The adjustment to determine inofof Ecotect wereand obtained solar radiation from buildings trees for each public space. The adjustment parameters to determine radiation in Ecotect were obtained from the space. weatherThe data file for the city of Chillán, available at www.meteonorm.com. The solar each public adjustment parameters to determine radiation in Ecotect were obtained from from the weather data file for the city of Chillán, available at www.meteonorm.com. The solar radiation obtained from Ecotect was compared with the results registered by HOBO micro station. the weather data file for the city of Chillán, available at www.meteonorm.com. The solar radiation radiation obtained from Ecotect was compared with the results registered by HOBO micro station. The morphoclimatic description of the selected spaces the station. following factors: obtained from Ecotect was compared with the resultspublic registered byconsidered HOBO micro description of the selected public spaces considered thesky following factors: totalThe areamorphoclimatic and land coverage of each public space, height–width ratio and view factor in The morphoclimatic description of the selected public spaces considered the following factors: total area and land 3)coverage of each public space, height–width and was sky calculated view factor in checkpoints (Figure and building height in the adjacent blocks. Theratio total area from total area and land coverage of each public space, height–width ratio and skyarea view factor in checkpoints checkpoints (Figure 3) building height in morphoclimatic the adjacent blocks. The totalfor calculated from the layer in ArcGIS; theand method of obtaining parameters thewas others is detailed in (Figure 3) and building height in the adjacent blocks. The total area was calculated from the layer the layer in ArcGIS; the method of obtaining morphoclimatic parameters for the others is detailed in in Table 1. ArcGIS; the method of obtaining morphoclimatic parameters for the others is detailed in Table 1. Table 1.

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Table 1. Morphoclimatic parameters of selected public spaces. Parameters Land cover

Method Recognition of land cover inside public spaces on a QuickBird mosaic image of the Google Earth program, from December 2016, and then validated in field work in January 2017

Building height

This was obtained from the individualization of the buildings available in the coverage provided by the National Institute of Statistics. Then, each construction was assigned an estimated height, according to the number of floors observed in the land. An average height of three meters per level was determined, according to the construction regulations

Height-width ratio

This index expresses the ratio between the height of the buildings (H) and the width of the street (W). The width of the streets was measure in the Ecotect software from the information of blocks of the National Institute of Statistics for the year 2015

Sky view factor

This index calculates the percentage of opening or closing of the streets towards the sky, on a scale from 0 to 1, where 1 represents an entirely open space and 0 a completely closed space. Modeling obtained this factor in the Autodesk Ecotect Analysis program based on the 3D model of the buildings, trees and any obstacle that could affect the visibility of the sky

At the same time, observations were developed from 29 January to 1 February 2016, to count the number of users located under the sun or in shady spots, five times every day (12, 14, 16, 18 and 20 h, local time) in different checkpoints of each public space (points in which the number of users is indicated in Figure 3). Also, for four days (29 January to 1 February 2016), between 11 and 19 h, a field survey was applied to a sample of men and women over 18 years old, selected at random, to consult them about climate perception. The method used by Lamarca [10] and Smith & Henriquez [11,12] to determine the user’s perception of urban climate considered the following elements: thermal sensation, solar exposure, wind speed, humidity and general comfort. All the questions included in the survey have an 11-point scale (0–10); values between four and six are considered acceptable for every parameter (Table 2). Table 2. Ranges of user’s climate perception. Parameter

0

Thermal perception Sun exposure Wind speed Air humidity Thermal comfort

1

2

3

4

Very cold I want more sun Little wind Very dry Cold, very uncomfortable

5

6

Good (Comfortable)

7

8

9

10

Very hot Too much sun Too much wind Very humid Hot, very uncomfortable

Source: Adapted from Cheng [16].

A total of 362 surveys were made (Table 3). In average, the 25% of the users observed were consulted, from 12.9% in Paseo Peatonal Arauco to 47.8% in Parque Sarita Gajardo. Table 3. User’s field survey. January, Friday 29

January, Saturday 30

January, Sunday 31

Public space

N.U.O.

N.U.S.

N.O.U.

N.U.S.

N.O.U.

N.U.S.

February, Monday 1 N.O.U.

N.U.S.

N.O.U.

N.U.S.

Plaza de Armas Paseo Peatonal Arauco Estero Las Toscas Parque Sara Gajardo Parque Bernardo O’Higgins

255 153 80 25

21 21 4 15

122 100 62 20

26 17 9 11

121 37 54 24

39 17 16 10

186 267 92 23

35 17 17 8

684 557 288 92

121 72 46 44

50

20

55

14

89

21

43

24

237

79

Note: N.U.O. is a number of users observed, and N.U.S. is a number of users surveyed.

Total

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Figure 3. Land cover in selected public spaces. the visitor’s observation is Figure 3. Land cover in selected public spaces. Note:Note: each each of theof visitor’s observation points points is indicated indicated in Figure 3, using a different prefix for each public space: Plaza de Armas (PA), Paseo in Figure 3, using a different prefix for each public space: Plaza de Armas (PA), Paseo Peatonal Arauco Peatonal Arauco (PP), Parque Estero Las Toscas (LT), Parque Sarita Gajardo (SG) and Parque (PP), Parque Estero Las Toscas (LT), Parque Sarita Gajardo (SG) and Parque Monumental Bernardo Monumental Bernardo O’Higgins (BO). O’Higgins (BO).

3. Results 3. Results 3.1. Morphoclimatic Description of Selected Public Spaces 3.1. Morphoclimatic Description of Selected Public Spaces Chillán public spaces were classified into seven groups: median strip, soccer field, sports center, Chillán public spaces were into seven groups: strip, soccer sports center, stream border, park, square andclassified pedestrian walk. There are 323median public spaces with a field, total area of 84.2 stream border, park, square and pedestrian walk. There are 323 public spaces with a total area ha, which amount to 2.8% of the city’s surface. Most public spaces are squares; there are 155, scattered of 84.2 ha, which amount to 2.8% of1.2% the city’s Most public spaces squares; areof155, around the city and representing of the surface. urban area. Their average areaare is 0.23 ha, butthere several scattered the andmeters. representing of the urban area. Their average is 0.23 them doaround not reach 400city square The six 1.2% city parks have a more significant average area area (1.3 ha).ha, butStream several of them do not reach 400 square meters. The six city parks have a more significant average borders are related to natural elements of the urban environment. For example, Estero Las area (1.3 ha). Stream to natural elements of are the aurban environment. Toscas, which givesborders its nameare to related the homonymous park. There considerable numberFor of example, soccer fieldsLas (38). These which are located low and to middle-income residential and scarce vegetation Estero Toscas, givesinits name the homonymous park.areas There arehave a considerable number of cover. soccer fields (38). These are located in low and middle-income residential areas and have scarce Among the public spaces of Chillán, the biggest green area is Parque Monumental Bernardo vegetation cover. O’Higgins (3.4 ha). The second place belongs to Parque Sarita Gajardo (3 ha), which is part of a major

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Among public spaces of Chillán, the biggest green area is Parque Monumental Bernardo Atmosphere 2018,the 9, x FOR PEER REVIEW 6 of 16 Atmosphere 2018, x FOR PEER REVIEW 6 of 16 O’Higgins (3.49,ha). The second place belongs to Parque Sarita Gajardo (3 ha), which is part of a major project sponsored sponsored by by the the local local government. government. Plaza de Armas covers 1.8 ha. The smallest public spaces project sponsored by the local government. PlazaArauco, de Armas covers 1.8 ha. smallest public spaces are Parque Estero Las Toscas and Paseo with 11and 0.6 ha respectively. Toscas and Paseo Peatonal Peatonal Arauco, with and 0.6 haThe respectively. are Parque Estero Las Toscas and Paseo Peatonal Arauco, with 1 and 0.6 ha respectively. 3.1.1. Land Cover Cover inside inside Public Public Spaces Spaces 3.1.1. Land 3.1.1. Land Cover inside Public Spaces Except for Arauco, 98% of whose areaarea is paved, all public spaces spaces selectedselected in Chillán Except forPaseo PaseoPeatonal Peatonal Arauco, 98% of whose is paved, all public in Except for Paseo Peatonal Arauco, 98% of whose area is paved, all public spaces selected in have green patches covered with grass: 41% Plaza de Armas, 38% Parque Monumental Bernardo Chillán have green patches covered with grass: 41% Plaza de Armas, 38% Parque Monumental Chillán have green patches covered with grass: 41% Plaza de Armas, 38% Parque Monumental O’Higgins, 34% Parque Sarita Gajardo 20.5%and Parque Estero LasEstero ToscasLas (Figure 3). (Figure 3). Bernardo O’Higgins, 34% Parque Saritaand Gajardo 20.5% Parque Toscas Bernardo O’Higgins, 34% Parque Sarita Gajardo and 20.5% Parque Estero Las Toscas 3).area, The smallest paved area is in Parque Sarita Gajardo. It represents only 5.4% of (Figure the total total area, The smallest paved area is in Parque Sarita Gajardo. It represents only 5.4% of the The smallest paved area is in Parque Sarita Gajardo. It represents only 5.4% of the total with 3% occupied by two multi-courts. In Parque Monumental Bernardo O’Higgins, the paved area with 3% occupied by two multi-courts. In Parque Monumental Bernardo O’Higgins, the paved area, area with 3% for occupied multi-courts. In Parque Monumental Bernardo O’Higgins, the paved area accounts its territory, 10% is (Figure 4) meters accounts for 38% 38% of ofby itstwo territory, 10% of of which which is aa viewpoint viewpoint (Figure 4)at atsix six metershigh. high. accounts for 38% of its territory, 10% of which is a viewpoint (Figure 4) at six meters high.

Figure Monumental Bernardo Bernardo O’Higgins. O’Higgins. Source: Source: personal personal archive. archive. Figure 4. 4. Viewpoint Viewpoint Parque Parque Monumental Figure 4. Viewpoint Parque Monumental Bernardo O’Higgins. Source: personal archive.

Parque Sarita Gajardo shows the greater area covered by bare ground: 69% of the total surface, Parque Sarita Gajardo shows the area covered by bare ground: 69% Parque Gajardo the greater greater baresquare ground: 69% of of the the total total surface, surface, 47% of whichSarita is occupied byshows two soccer fields area withcovered 6800 andby1500 meters respectively. Grass 47% of which isisoccupied by two soccer fields with 6800 and 1500 square meters respectively. Grass in 47% of which occupied by two soccer fields with 6800 and 1500 square meters respectively. Grass in the park is poorly maintained (Figure 5): it is revealed to be a “brown area”. the park is poorly maintained (Figure 5): it is revealed to be a “brown area”. in the park is poorly maintained (Figure 5): it is revealed to be a “brown area”.

Figure 5. Soccer field Parque Sarita Gajardo. Source: personal archive. Figure 5. 5. Soccer Soccer field field Parque ParqueSarita SaritaGajardo. Gajardo. Source: Source: personal personal archive. archive. Figure

The presence of water, as well as related objects and activities, was also considered in this study. The presence of water, as well as objects and activities, was Las alsoToscas, considered in the thisstream study. As expected, the highest abundance of related this element is observed in Estero where The presence of water, as well asofrelated objectsisand activities, was also considered in the thisstream study. As expected, the highest abundance this element observed in Estero Las Toscas, where channel accounts for 33% of its area. In the other public spaces, water is only available in water As expected, the highest abundance of this element observed in Estero LasisToscas, where theinstream channel accounts of (Parque its area. In the otherisBernardo public spaces, water only 6). available water fountains or water for play33% zones Monumental O’Higgins) (Figure channel accounts for 33% of its area. In the other public spaces, water is only available in water fountains or water play zones (Parque Monumental Bernardo O’Higgins) (Figure 6). fountains or water play zones (Parque Monumental Bernardo O’Higgins) (Figure 6).

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Figure Monumental Bernardo Bernardo O’Higgins. O’Higgins. Source: Source: personal archive. Figure 6. 6. Water Water play play zones zones in in Parque Parque Monumental personal archive.

All public spaces have built areas, as pergolas (Plaza de Armas), kiosks (Paseo Peatonal Arauco All public spaces have built areas, as pergolas (Plaza de Armas), kiosks (Paseo Peatonal Arauco and Parque Estero Las Toscas), warehouses (Parque Sarita Gajardo) or bathrooms (Parque and Parque Estero Las Toscas), warehouses (Parque Sarita Gajardo) or bathrooms (Parque Monumental Monumental Bernardo O’Higgins). They all have benches, trashcans, signals and other public Bernardo O’Higgins). They all have benches, trashcans, signals and other public furniture. furniture. Trees higher than 1.5 m, as well as treetop cover, were calculated for each public space. The highest Trees higher than 1.5 m, as well as treetop cover, were calculated for each public space. The number of individual trees is in Parque Sarita Gajardo (85) and Parque Monumental Bernardo highest number of individual trees is in Parque Sarita Gajardo (85) and Parque Monumental Bernardo O’Higgins (86). On the other hand, the largest treetop cover is in Plaza de Armas (32% of its area). O’Higgins (86). On the other hand, the largest treetop cover is in Plaza de Armas (32% of its area). In the adjacent blocks of the public spaces, the average built surface varies considerably. In three In the adjacent blocks of the public spaces, the average built surface varies considerably. In three of them, the average of the built surface is over 50% of the total area: Plaza de Armas of Chillán (59.1%), of them, the average of the built surface is over 50% of the total area: Plaza de Armas of Chillán Paseo Peatonal Arauco (57.1%) and Parque Sarita Gajardo (54.6%). In the other two, it is near 30%: (59.1%), Paseo Peatonal Arauco (57.1%) and Parque Sarita Gajardo (54.6%). In the other two, it is near Parque Estero Las Toscas (33.7%) and Parque Monumental Bernardo O’Higgins (27.4%). 30%: Parque Estero Las Toscas (33.7%) and Parque Monumental Bernardo O’Higgins (27.4%). 3.1.2. Buildings Height 3.1.2. Buildings Height Chillán has few high buildings. Low structures prevail in the blocks surrounding the public Chillán has few high buildings. Low structures prevail in the blocks surrounding the public spaces. The taller buildings are beside Paseo Peatonal Arauco and in front of Plaza de Armas, with 18 spaces. The taller buildings are beside Paseo Peatonal Arauco and in front of Plaza de Armas, with and 8 m respectively (Grand Hotel Isabel Riquelme and Governance building). Most buildings around 18 and 8 m respectively (Grand Hotel Isabel Riquelme and Governance building). Most buildings Plaza de Armas are over three floors high. Likewise, buildings surrounding Paseo Peatonal Arauco around Plaza de Armas are over three floors high. Likewise, buildings surrounding Paseo Peatonal usually have two or three levels. Arauco usually have two or three levels. There are only three higher buildings in the proximities of these public spaces: two of them There are only three higher buildings in the proximities of these public spaces: two of them have have nine levels (27 m), and the third has 18 floors (54 m) and is the highest structure inside the city. nine levels (27 m), and the third has 18 floors (54 m) and is the highest structure inside the city. These These buildings do not change the H/W ratio, but they increase the available shade. buildings do not change the H/W ratio, but they increase the available shade. 3.1.3. Height–Width (H/W Ratio) 3.1.3. Height–Width (H/W Ratio) This index affects the percentage of the total space receiving direct solar radiation and the number Thisduring index which affectsthis theoccurs. percentage the totaltends space solar radiation and the of hours Whenof this value to receiving 0, there is adirect higher difference between the number of hours during which this occurs. When this value tends to 0, there is a higher difference height of buildings and the width of the street; hence, the latter are more exposed to solar radiation. between thewhen height ofratio buildings the width of theare street; hence, latter are more exposed to Conversely, this is nearand 1, height and width similar, andthe there is more shadow available solar radiation. Conversely, when this ratio is near 1, height and width are similar, and there is more (provided by the buildings). shadow (provided by the buildings). Theavailable sites measured in Chillán generally have an H/W under 0.1, which shows an open profile The sites measured in Chillán generally have an exception H/W under 0.1, which shows an open profile associated with parks and squares (Table 4). The only is Paseo Peatonal Arauco, where the associated with parks and squares (Table 4). The only exception is Paseo Peatonal Arauco, where street width is smaller than the height of the buildings; therefore, direct solar radiation decreases. the street width is smaller than the height of the buildings; therefore, direct solar radiation decreases.

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Table 4. Morphoclimatic parameters and perceived thermal comfort in each checkpoint. SVF: sky view factor; HW: height–width ratio. Public Space

Checkpoint

SVF

H/W

Solar Radiation (12 to 13 PM) (Wm2 )

Solar Radiation (5 to 6 PM (Wm2 )

Perceived Thermal Comfort (Average)

Plaza de Armas

PA1 PA2 PA3 PA4

0.382 0.648 0.367 0.646

0.056 0.056 0.056 0.043

226.18 371.57 266.22 375.27

80.24 300.95 88.69 127.37

7.6 7.3 7.9 8.1

Paseo Peatonal Arauco

PP1 PP2 PP3 PP4 PP5

0.756 0.738 0.437 0.485 0.563

0.221 0.232 0.236 0.222 0.434

398.51 395.47 296.77 334.75 352.2

310.5 309.43 232.13 113 119.19

7.7 8 7.6 7.8 8.7

Parque Estero Las Toscas

LT1 LT2 LT3 LT4

0.175 0.723 0.823 0.388

0.128 0.130 0.073 0.068

139.62 385.37 405.44 232.84

224.41 305.84 312.96 275.48

7.5 7.7 8.3 8.3

Parque Sarita Gajardo

SG1 SG2 SG3 SG4 SG5

0.812 0.813 0.79 0.559 0.696

0.039 0.053 0.033 0.105 0.088

404.69 403.47 401.62 334.22 382.37

312.69 312.26 136.72 287.69 304.78

7.2 8.3 7.9 7.4 7

Parque Monumental Bernardo O’Higgins

BO1 BO2 BO3 BO4 BO5 BO6

0.799 0.461 0.801 0.541 0.632 0.591

0.018 0.020 0.078 0.020 0.041 0.056

400.19 250.32 402.7 337.94 372.84 357.81

311.1 263.68 311.99 245.29 126.51 121.18

7.9 8 8.3 8.2 8.7 7.7

3.1.4. Sky View Factor Similar to H/W ratio, sky view factor (SVF) also affects direct solar radiation and shadow availability. In the selected public spaces, the average values of this indicator range from 0.51 in Plaza de Armas to 0.747 in Parque Sarita Gajardo (Table 4). Thus, in the first public space mentioned, half of the sky is visible. As this value increases, sky openness also increases and solar radiation is more intense. Even though this indicator does not show much difference from one public space to another, it varies significantly along each of the selected spaces, except for Parque Sarita Gajardo (Table 4), where it is over 0.7 in all checkpoints. This high value shows great sky openness, due to its width as well as to the surrounding streets. This indicator is low in three of the selected public spaces: Plaza de Armas (0.37 and 0.38 in checkpoints PA1 and PA3, respectively, Figure 4); Parque Estero Las Toscas (0.39 in checkpoint LT4, Figure 4) and Parque Monumental Bernardo O’Higgins (0.46 in checkpoint BO2, Figure 2). These values are due to the considerable number of trees, which results in less sky visibility. In Paseo Peatonal Arauco, SVF increases when moving away from Plaza de Armas (Table 4); in its second block, it is over 70% (checkpoints PP1, PP2, and PP3 in Figure 4); in the remaining checkpoints (PP4, PP5, and PP6, in Figure 4), the average sky visibility is near 50%. During summer, shadow availability is a critical factor to increase climate comfort in public spaces. In Chillán, the shadow is provided by the trees inside each public space as well as by buildings in its surroundings. The analysis of shadow availability in all public spaces shows that the prevailing value is near 30%. In Parque Estero Las Toscas and Parque Sarita Gajardo, the shadow is unavailable in as much as 70% of the total area at any time from 12 to 18 h. The remaining three public spaces have some shadow during daytime: Paseo Peatonal Arauco (30%), Plaza de Armas (14%) and Parque Bernardo O’Higgins (13.5%). Inside the parks, the shadow is related to the presence of trees. Instead, in Paseo Peatonal Arauco, buildings provide it. The first is permeable to solar radiation, which results in higher values for the latter.

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3.2. Climatic Descriptions, Summer 2015–2016, and Heat Wave from 30 January to 1 February 2016 3.2. Climatic Descriptions, Summer 2015–2016, and Heat Wave from 30 January to 1 February 2016 Data registered by Chilean Meteorological Service in Bernardo O’Higgins station—located in Dataarea registered by Chilean Meteorological Service in Bernardo O’Higgins the the rural surrounding Chillán—shows that, during 30, 31 January and 1station—located February 2016, in there rural area surrounding Chillán—shows that, during 30, 31 January and 1 February 2016, there was was a heat wave with a peak of 36 °C in the rural sector. This peak is the highest temperature a heat wave with a peakby of this 36 ◦ C in the rural sector. This peak is According the highesttotemperature registered registered that summer institution in the entire country. the instruments used that summer this institution in the 38 entire country. to the instruments used in this study, in this study, by temperatures exceeded °C inside theAccording urban area. temperatures exceeded 38 ◦ Cfrom inside urbantoarea. During the field survey 29the January 1 February 2016, atmospheric temperatures in Plaza Duringofthe field survey 29 25 January February 2016, atmospheric Plaza de Armas Chillán rangedfrom from °C toto331 °C, with peak temperaturestemperatures between 16 in and 18 de h. ◦ C to 33 ◦ C, with peak temperatures between 16 and 18 h. Relative Armas of Chillán ranged from 25 Relative humidity reached its minimum value during the afternoon (36%). The four checkpoints humidity minimum value during the results. afternoon (36%).behavior The fourcould checkpoints located Plaza located inreached Plaza deitsArmas showed comparable Similar be observed inin Parque de Armas showed comparable results. SimilarEstero behavior bewhere observed in Parque Monumental Monumental Bernardo O’Higgins and Parque Las could Toscas, the temperature reached 35 ◦ C. Bernardo O’Higgins and Parque Estero Las Toscas, where the temperature reached 35 °C. ◦C ◦C In Paseo Peatonal Arauco, temperatures fluctuated from 27 °C to 30 °C at 12 o’clock, increasing ◦C The checkpoint checkpoint PP2 PP2 (Figure (Figure 7) 7) shows shows aa greater greater difference difference with with the the rest of the up to 35 °C at 16 h. The ◦ C), while humidity differs even 3% from one checkpoint to another at the measurement points (+2 measurement points (+2 °C), while humidity differs even 3% from one checkpoint to another same time. In Parque Sarita Gajardo, as well as in the rest rest of of public public spaces, spaces, the the temperature temperature reached reached its peak ◦ C) between the minimum and between 16 and 18 h. Until 16 h, there are significant differences (2 between Until °C) maximum temperatures temperaturesregistered registeredininthe thedifferent differentcheckpoints. checkpoints.These These differences tend to lessen at maximum differences tend to lessen at 18 18 h, with the only exception being checkpoint SG5 (Figure 3), located in the playground, which shows h, with the only exception being checkpoint SG5 (Figure 3), located in the playground, which shows ◦ C at 20 temperatures. The The maximum maximum average average register register is is 36 36 °C higher temperatures. at 20 h; all checkpoints have similar ◦ C). values (near 30 °C).

Figure 7. Playground Parque Sarita Gajardo. Source: personal archive. Figure 7. Playground Parque Sarita Gajardo. Source: personal archive.

The meteorological micro-station is installed in a courtyard inside the Biobío university The meteorological micro-station installed in courtyard inside the Biobío university (Campus (Campus La Castilla), surrounded byisbuildings of atwo and three floors, and with the presence of La Castilla), surrounded by buildings of two and three floors, and with the presence of vegetation vegetation (grass and trees), in conditions similar to those of the public spaces studied. As shown in (grass 5, and trees), data in conditions to those of the public Asdetermined shown in Table 5, Table average estimatedsimilar with the radiation model arespaces quite studied. like those by the average data estimated with the radiation model are quite like those determined by the meteorological meteorological micro-station, with a slight difference of 60 W/m2 at noon and only 12 W/m2 in the micro-station, with a slight difference of 60 W/m2 at noon and only 12 W/m2 in the afternoon. afternoon. Table 5. Comparison of global radiation (in W/m22 ) estimated and measured in Campus La Castilla. Table 5. Comparison of global radiation (in W/m ) estimated and measured in Campus La Castilla.

Estimated Data Data (30 (30 January January 2016) 2016) Estimated 12 to 13 h 17 to 18 h 12 to 13 h 17 to 18 h 403.8 312.4 403.8 312.4

Measured MeasuredData Data(30 (30January January2016) 2016) 12 to 13 h 17 to 18 12 to 13 h 17 to 18hh 462.5 325 462.5 325

Source: Constructed authors data gathered byand Ecotect by the meteorological Source: Constructed by by the the authors usingusing data gathered by Ecotect by theand meteorological micro-station microlocated in Campus Castilla, UniversityCastilla, of Biobío.University of Biobío. station located in Campus

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Global radiation varies significantly inside each public space, particularly in the afternoon hours Global radiation varies significantly inside each public space, particularly in the afternoon hours (17 to 18 h) (Table 4), because of the solar angle and the shadows projected by buildings and trees. (17 to 18 h) (Table 4), because of the solar angle and the shadows projected by buildings and trees. During noon, average radiation is near its maximum value and covers larger areas within public During noon, average radiation is near its maximum value and covers larger areas within public spaces. In both time ranges, minimum values cover a small surface. spaces. In both time ranges, minimum values cover a small surface. However, all public spaces show high radiation values between noon and 13 h: the greatest spatial However, all public spaces show high radiation values between noon and 13 h: the greatest homogeneity for these values is found in Parque Estero Las Toscas and Parque Sarita Gajardo. In the spatial homogeneity for these values is found in Parque Estero Las Toscas and Parque Sarita Gajardo. other public radiation values show becausebecause of the difference between In the otherspaces, public the spaces, the radiation valuesgreater show diversity, greater diversity, of the difference places exposed toexposed solar radiation shadedand sites. Such sites. is the Such case of the Plazainde between places to solarand radiation shaded is higher the casevegetation of higher in vegetation Armas and the Parque Monumental Bernardo O’Higgins or the continuous facade of the buildings the Plaza de Armas and the Parque Monumental Bernardo O’Higgins or the continuous facade of the flanking the Paseo Peatonal Arauco. buildings flanking the Paseo Peatonal Arauco. 3.3. Urban Climate Perception and its Relationship with Morphoclimatic Parameters 3.3. Urban Climate Perception and its Relationship with Morphoclimatic Parameters During who feel feel thermal thermal comfort comfortand andthose thosewho whofeel feel Duringthe themorning, morning, the the proportion proportion of of users users who uncomfortable is quite similar; nevertheless, in the afternoon (12 to 16 h) and the evening, most uncomfortable is quite similar; nevertheless, in the afternoon (12 to 16 h) and the evening, most people ◦ C). people discomfort, particularly 18 h when the temperature its(38 peak (38The declaredeclare discomfort, particularly aroundaround 18 h when the temperature reachesreaches its peak °C). The individual analysis of each public selected that in Sarita Parque Sarita Gajardo, positive individual analysis of each public spacespace selected shows shows that in Parque Gajardo, positive thermal thermal perception is near 30%sample. of the sample. In the remaining ranges from 10Even to 15%. Even perception is near 30% of the In the remaining spaces, itspaces, rangesitfrom 10 to 15%. though though Plaza de Armas has significant vegetation cover, 95% of its are in discomfort (Figure 8a). Plaza de Armas has significant vegetation cover, 95% of its users areusers in discomfort (Figure 8a).

Figure 8. 8. Urban Urban climate climate perception. Figure perception.

Solar exposure shows similar perceptions. Near 100% of the users surveyed in the Sarita Gajardo exposureBernardo shows similar perceptions. oftoo themuch userssun. surveyed in the SaritaArauco Gajardo andSolar Monumental O’Higgins parks sayNear that 100% there is In Paseo Peatonal and Bernardo O’Higgins that there is too much sun. In Paseo Arauco andMonumental Parque Estero Las Toscas, some parks users say enjoy solar exposition, though only 20%Peatonal of the sample and Parque Estero Las Toscas, some users enjoy solar exposition, though only 20% of the sample chose values between 4 and 6 (Figure 8b). Only four people chose the option “I want more sun”; chose two of them in Paseo Peatonal Arauco, one in Plaza de Armas and another in Parque Sarita Gajardo.

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values between 4 and 6 (Figure 8b). Only four people chose the option “I want more sun”; two of them in Paseo Peatonal Arauco, one in Plaza de Armas and another in Parque Sarita Gajardo. Wind is an essential weather agent since it helps to attenuate elevated temperatures. Its intensity is differently perceived by the persons sampled (Figure 8c). Nevertheless, users who perceive that there is little wind and those who feel comfortable with its intensity are very similar in amount. In Plaza de Armas, 60% of the sample chose the option “little wind”. A very small group of users perceived too much wind, particularly during the evening; most of them were visiting Parque Sarita Gajardo, Parque Estero Las Toscas and Parque Bernardo O’Higgins. During daytime, air humidity registered in the checkpoints located inside the selected public spaces ranges from 45% to 55%. Within the sample, humidity and wind speed show a similar perception. During the afternoon, most people choose the option “too dry”. On the other hand, at noon, this alternative and “comfortable” show equivalent results (Figure 8d). Even though Parque Estero Las Toscas is located in a stream bank, it has the highest proportion of uncomfortable users because of air dryness. In the remaining public spaces, satisfaction with this parameter is approximately 50%. 3.4. Use of Public Spaces and Distribution of Their Users About 70% of respondents recognize seasonal changes in their use of public spaces. Just over one-third of them suggest the following sequence, in decreasing order: summer–spring–autumn–winter. The options in which the summer season ranks first exceeded 200 respondents, which represents about 60% of the sample. None of the respondents chose the option “does not assist” for the spring–summer seasons. According to survey results, the majority of respondents in Parque Estero Las Toscas and Parque Monumental Bernardo O’Higgins do not visit them in fall or winter. In the other three public spaces selected, most users choose “once or twice a week”. These results might be explained by the location and function of each public space. Indeed, Paseo Peatonal Arauco and Plaza de Armas are located downtown near the central business district, and Parque Sarita Gajardo is in a mainly residential neighborhood and is equipped for sports practice. Weather—heat, cold, rain—explain to an extent the seasonal differences in the use of public spaces. In Parque Bernardo O’Higgins, about 90% of the respondents point to the bad weather—cold, rain—as responsible for the few visitors in winter. At the same time, the increase in its users during summer would obey “better climatic conditions”—higher temperatures. Respondents claim that “in summer, it is hotter and people spend more time outdoors”. A visitor in Paseo Peatonal Arauco noted that “in winter, the sole visitors are those who have to pass through the walk“ because “it is colder and darkens earlier”. Others factors that affect the number of times public spaces are used in winter are the decrease in free time, fewer daylight hours, fewer users and fewer activities. The observation of visitors complemented the data obtained through the survey. There are significant differences in the flow of users, depending on the social role of each public space. Thus, Plaza de Armas and Paseo Peatonal Arauco receive a greater number of attendants on Monday through Friday. With respect to the latter, the weekend studied constitutes an exception to the above in point A (PP_A in Figure 4), since a folkloric festival took place on Saturday, 30 January, at 19 h. On the other hand, the parks evaluated—Parque Sarita Gajardo and Parque Monumental Bernardo O’Higgins—concentrate their visitors on Saturdays and Sundays (Figure 9).

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number of users

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200 180 160 140 120 100 80 60 40 20 0 A

B

C

D

Plaza de Armas

E

A

B

B

C

D

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Paseo Estero Las Toscas Peatonal Arauco

A

B

C

D

Sarita Gajardo

A

B

C

D

E

F

Parque Bernardo O´Higgins

user observation points weekend

business days

Figure9.9.Frequency Frequency of ofusers usersaccording accordingto tothe themoment momentof ofthe theweek week(business (business days/weekend) days/weekend) during Figure during the field survey (from 29 January to 1 February 2016). the field survey (from 29 January to 1 February 2016).

When relating the comfort perceived by users with the environmental and urban parameters Whenarelating the comfort perceived by users with the environmental and urban parameters analyzed, statistically significant direct relationship between comfort and solar radiation (0.67) is analyzed, a statistically significant direct relationship between comfort and solar radiation (0.67) is obtained, which means that the higher the radiation, the greater the discomfort due to heat. In turn, obtained, which the sky higher the radiation, the greater the height–width discomfort due to heat. In Both turn, the radiation is means relatedthat to the visibility factor (0.46) and the ratio (−0.2). the radiation is related to the sky visibility factor (0.46) and the height–width ratio ( − 0.2). Both relations relations indicate that a greater opening of the sky—caused by fewer obstacles to visibility and a ratio indicate greater opening of the the streets sky—caused by the fewer visibility and a ratio between betweenthat the aheight and width of in which firstobstacles does nottoexceed the second—allows the the height and width of the streets in which the first does not exceed the second—allows the entry of entry of greater solar radiation to the surface. greater solarparameters radiation to therelate surface. These also to the number of users in each point of the public space. In the case These parameters also relate to the number of users each pointH/W of the public the case of the height–width ratio, this relationship is direct (0.5):inthe higher ratio, the space. greaterInpresence of the height–width ratio, this relationship is direct (0.5): the higher H/W ratio, the greater presence of of users. The two remaining factors are inversely related, SVF (−0.21) and solar radiation (−0.3), which users. The two remaining factors are inversely related, SVF ( − 0.21) and solar radiation ( − 0.3), which means that the greater the radiation caused by a greater opening to the sky, the lower the number of means greater the radiation caused byofa greater opening to the sky, the lower the number of users, that as athe result of the lower availability shadows, whether vegetation, buildings or some users, as a result of the lower availability of shadows, whether vegetation, buildings or some particular particular infrastructure produces them. infrastructure produces them. 4. Discussion 4. Discussion The results of the perceived thermal issues showed a positive relationship with air temperature The results of the perceived issues showed a positive with air temperature (0.32) and a negative correlationthermal with relative humidity (−0.24). relationship Similar results were founded in (0.32) and a negative correlation with relative humidity ( − 0.24). Similar results were founded in in Szeged, Hungary by Kántor et al. [17]. A study conducted in Australia showed that activities Szeged, Hungary by Kántor et al. [17]. A study conducted in Australia showed that activities in outdoor spaces decrease in the thermal threshold between 28 °C and 32 °C [18]. The authors also ◦ C and 32 ◦ C [18]. The authors also outdoor spaces decrease in the thermal threshold between 28 concluded that those spaces “resistant to heat”, which have, for example, trees with a greater canopy, concluded that those spaces “resistant to heat”, which have, for example, a greater canopy, are more widely used. The results of Sharifi et al. [19] also show that, facedtrees withwith the lack of measures are more widely used. The results of Sharifi et al. [19] also show that, faced with the lack of measures in in the public space to deal with episodes of heat stress, the population prefers to move to airthe public space to deal with episodes of heat stress, the population prefers to move to air-conditioned conditioned enclosures, which in turn increases the energy demand for refrigeration. Likewise, in a enclosures, turn increases the energy demand for refrigeration. Likewise, studyspaces of the study of thewhich city ofinFreiburg, Germany, it was concluded that the buildings adjacent in to apublic city of Freiburg, Germany, it was concluded that the buildings adjacent to public spaces affect the affect the availability of shadows in urban canyons and, in this way, increase the thermal comfort availability of shadows in urban canyons and, in this way, increase the thermal comfort [20]. [20]. In the case thethe citycity of Chillán, the availability of shade in the in parks mainly to the presence In the caseofof of Chillán, the availability of shade the isparks is due mainly due to the of vegetation, whereas in the Paseo Peatonal Arauco it is related to the buildings. Both mechanisms of presence of vegetation, whereas in the Paseo Peatonal Arauco it is related to the buildings. Both the provisionof ofthe shade are very to mitigate the to temperature the air whenofthe mechanisms provision of useful shade are very useful mitigate theoftemperature thetemperatures air when the exceed the thermal comfort thresholds; however, considering the Mediterranean climate of the city temperatures exceed the thermal comfort thresholds; however, considering the Mediterranean climate of the city and the cold conditions of winter, it is better to have less shade in this season,

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and the cold conditions of winter, it is better to have less shade in this season, allowing the insolation of the urban cover [21]; for example, through the consideration of deciduous vegetation. The above is related to the “right to the sun” proposed by Bitan [22] and by the municipality of Barcelona, in its Urban Ecology Plan, which, among other measures, determines the number of hours entitled to the sun that each city housing [23]. In this sense, it is essential for public spaces to consider climate sensitive urban design (CSUD), which allows access to shade, sun and wind protection [24]. The design paradigms of public spaces considered by urban planning instruments have not been able to incorporate the complexity of urban climates [25], especially in Latin American cities [26]. However, studies developed in Australian urban areas propose the application of CSUD and incorporation of water and vegetation as measures to mitigate heat to improve the thermal comfort conditions of outdoor public spaces [27]. Local Management of Public Spaces and Urban Climate Chillán has no local public policy regarding climate comfort and public spaces within the city. Municipal development plans and environmental ordinances of Chillán and Chillán Viejo—which make up the city—do not include this matter either. There are, however, some references in its urban planning instruments. Although both municipalities have valid communal regulatory plans (PRC in Spanish)—Chillán Viejo since 2012 and Chillán since 2016 [28,29]—they do not provide guidelines for the articulation of public spaces and existing green areas. The PRC set criteria for the density of occupancy and maximum building heights, which can affect the urban microclimate. Likewise, they determine the location of public spaces and green areas, as well as the allowed or forbidden uses in each of the different zones defined by them. The density of land occupation and building height directly affect the degrees of sky openness and the availability of shade and, therefore, the thermal comfort of public spaces. There is a gap between the allowed construction density in the areas where the selected public spaces are located and the current characteristics of the neighboring blocks; thus, presenting a wide margin for increasing densities. For example, the regulatory plan of the commune of Chillán allows a coefficient of 1—that is to say, 100% of the land can be built upon—for areas surrounding Plaza de Armas and Paseo Peatonal Arauco, and the current average coefficients amount to 60%. Seemingly, there is a gap between maximum heights allowed and current building heights. The prevalence of low structures could be explained by the higher costs involved in building high structures in a country with strong seismicity. The PRC of Chillán Viejo allows maximum heights ranging from 14 m in the mixed-use zone (commercial and residential area) to 20 m in the mixed-use zone. However, current structures on the blocks surrounding Parque Monumental Bernardo O’Higgins do not rise over five meters. At present, Chillán is a low-rise city. If its structures rose to the permitted maximum, the height-to-width ratio (H/W) and the sky visibility factor (SVF) would be modified. The modification in the H/W and the SVF would cause a decrease in direct solar radiation and might favor comfort in public spaces during the summer. Nevertheless, it would have adverse effects on temperature and comfort in winter. Therefore, the increase in vegetation (particularly deciduous vegetal species) is the best alternative to modify sky visibility and cool the city in summer. Likewise, at the national level, there are no explicit guidelines to improve micro-climatic conditions in public outdoor spaces. The National Urban Development Policy [30] includes, in the area of social integration, two objectives regarding this matter. One seeks to “ensure equal access to urban public goods”, and the other refers to the articulation of public spaces, by the interconnection of parks and green areas, generating tours and circuits, both at the neighborhood and city scale. Furthermore, the document “The Human Dimension in Public Space. Recommendations for Analysis and Design” of the Ministry of Housing and Urbanism (MINVU in Spanish) [31], recently published by the Program for Public Spaces of the Ministry of Housing and Urban Development, provides 80 design guidelines for public spaces. It declares that “the functionality of public space, its dimensions, climatic comfort, and activities have a greater weight in the experience of its visitors

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than the formal characteristics typically privileged by many architects. The shape of the space must be subject comfort and human theFinally, other way Finally, it is to worth mentioning the activities, Adaptingnot Cities Plan to it Climate isaround”. worthChange mentioning [32], which the Adapting has Cities Plan to Climate C Finally, it is worth mentioning Adapting Plan to Climate Change [32], whichin has recently recently concluded a citizenship consultationthe process. recently TheCities plan concluded is focused a citizenship on the risks consultation involved process. The plan is focused o climate change at national level. The concept of process. urban climate climate change is absent national and, hence, level. The concern concept for of in urban climate is absent and concluded a citizenship consultation The plan isatfocused on thethe risks involved climate temperature is restricted tolevel. the events of heat and temperature cold waves, is which restricted arehence, to usually the recorded of for heat by and cold waves, which ar change at national The concept of urban climate is absent and, theevents concern temperature meteorological stations outside limits, meteorological such the stations stationinstalled Bernardo outside the urban in stations limits, such as the station is restricted toinstalled the events of heatthe andurban cold waves, whichasare usually recorded byO’Higgins meteorological Chillán. Itinstalled is essential thatthe planning instruments consider Chillán. urban is essential climatology that planning toinunderstand instruments consider outside urban limits, such as the stationIt Bernardo O’Higgins Chillán. It isthe essential that urban climatol necessary planning relationships between the characteristics of necessary planning, relationships urban design, between and climate, the characteristics which, in of planning, urban design instruments consider urban climatology to understand the necessary relationships between turn, affectthe thermal comfort and climate quality in each turn, sector affect ofthermal the city. comfort andaffect climate quality in eachand sector of the city. characteristics of planning, urban design, and climate, which, in turn, thermal comfort climate quality in each sector of the city. 5. Conclusions 5. Conclusions 5. Conclusions The city of Chillán has few green public areas whose The combined city of cover Chillán only hasamounts few green to public 1.7 m2 per areas whose combined cover onl The cityan of urban Chillánmorphology has few green public areas whose combined cover only amounts 1.7 height m2 perand is little woode inhabitant. Also, it has of low height inhabitant. and isAlso, little itwooded, has an urban which morphology allows greater oftolow Also, it has an morphology of lowspaces, height is little wooded, which allows insolation inhabitant. of open areas, affecting theurban climate quality insolation of public of openand especially areas, affecting during the hotclimate summers qualitygreater of public spaces, especia insolation open areas, the climate quality of public especially during hot summers and episodes of heatof waves, such asaffecting those observed in and recent episodes years. ofPaseo heatspaces, waves, Peatonal such Arauco as those revealed observed in recent years. Paseo Pe and episodes of heat waves, as thosethe observed in recent years. Peatonal revealed the worst comfort conditions since it is such an impervious urban worstcanyon comfort with conditions very Paseo little since shade. it is an Arauco impervious urban canyon with ver the worst comfort sincespace it is an impervious canyon with little shade. The distribution of usersconditions in each public throughout The distribution theurban day depends of users on in itsvery each social public function space throughout the day depen The distribution of users each public space throughout day depends on its socialnumber function and the availability of sun and shade. Theinlargest number and the of users availability were observed ofthe sun and in shade. the evening The largest from of users were obser 18 h onwards, when temperature decreased, andThe shade 18 havailability onwards, increased. temperature In contrast, decreased, visitors in shade availability increased and the availability of sun and shade. largest numberwhen of users were observed in the and evening from Arauco walkway and Plaza de Armas were distributed Arauco more homogeneously and Plaza during de Armas the day, were since distributed more homogeneousl 18 h onwards, when temperature decreased, andwalkway shade availability increased. In contrast, visitors these spaces are associated withand commercial andspaces various arecity associated services. with In allcommercial cases, around activities in Arauco walkway Plaza deactivities Armasthese were distributed more homogeneously during the and day,various city servi 75% of users looked the shade. The city has high-density 75% of users neighborhoods looked and forand the shade. few vegetated Theservices. citypublic has high-density since theseforspaces are associated with commercial activities various city In all cases, neighborhoods an spaces. Consequently, parks have become theshade. only option spaces. for Consequently, facing extreme parks heat have events become (residential thefew only option for facing extreme around 75% of users looked for the The city has high-density neighborhoods and vegetated air coolingpublic systems are still relatively uncommon). coolingthe systems are stillfor relatively spaces. Consequently, parks haveair become only option facing uncommon). extreme heat events Local(residential public environmental should payLocal attention public to environmental the complex relations management between should pay attention to the com air cooling management systems are still relatively uncommon). urban climate, public spacesenvironmental and thermal comfort thaturban directly climate, affect the quality spaces ofthe and people’s thermal lives. comfort This that directly affect the quali Local public management should paypublic attention to complex relations between is particularly important increasing episodes iscomfort particularly of high that temperatures important and given intense thequality increasing heat waves episodeslives. of high temperatures urban climate, given publicthe spaces and thermal directly affect the of people’s which have occurred in the city of Chillán in recent summers, which have which occurred are related in the to city urban of Chillán heat islands in recent summers, This is particularly important given the increasing episodes of high temperatures and intense heat which are relate and climate change. and climate change. waves which have occurred in the city of Chillán in recent summers, which are related to urban heat Planning andand urban design proposals to improve comfort Planning andand climatic urbanquality designinproposals public spaces to improve comfort and climatic islands climate change. are crucial elements. Some examples include measures are crucial such as elements. planting Some more examples trees, particularly include Planning and urban design proposals to improve comfort and climatic quality in publicmeasures spaces aresuch as planting m deciduouscrucial species, temporary/seasonal shading devices deciduous such such as species, umbrellas, temporary/seasonal andmore installing shading waterdevices such as umbrellas, an elements. Some examples include measures as planting trees, some particularly deciduous features for urban users of squares and parks. Undertaking features actions for urban adjusted users to of local squares climate and will parks. result Undertaking species, temporary/seasonal shading devices such as umbrellas, and installing some water featuresactions adjusted to in a betterfor quality of users life forofthe population and more insustainable a better quality cities.of life for to thelocal population cities. urban squares and parks. Undertaking actions adjusted climateand willmore resultsustainable in a better quality of life for the population and more sustainable cities.

Author Contributions: The article shows the results of the Author doctoralContributions: research of P.S.The P.S.article conceived, showsdesigned the results andof the doctoral research of P.S. P.S wrote the first draft of the article, and reviewed and edited wrote the final the first version. draft C.H. of the led article, the overall and reviewed research and and edited the final version. C.H. le Author Contributions: The article shows the results of the doctoral research of P.S. P.S. conceived, designed and wrote the the firstfirst draft of final the article, and edited finalthe version. C.H. led the overall research and reviewed and edited and draft. and reviewed reviewed andthe edited first and final draft. reviewed and edited the first and final draft. Acknowledgments: The contribution of eight students from Acknowledgments: the University of The Biobío, contribution who wereofindispensable eight students from the University of Biobío The contribution eight students the University of the Biobío, who were is indispensable for Acknowledgments: for the realization of surveys and fieldwork, isofgratefully for acknowledged. the from realization of Likewise, surveys andhelp fieldwork, provided by gratefully acknowledged. Likewi the realization of surveys and fieldwork, is gratefully acknowledged. Likewise, the help provided by Cristóbal Cristóbal Lamarca in the calculation of global radiation is Cristóbal highly appreciated. Lamarca inThis the research calculation had ofthe global support radiation of is highly appreciated. This re Lamarca in the calculation of global radiation is highly appreciated. This research had the support of National National Commission National Commission offor Scientific through and itsits Technological programs: Research (CONICYT) of Ch Commissionfor forScientific Scientificand andTechnological TechnologicalResearch Research(CONICYT) (CONICYT) ofChile Chile through programs: National National Doctoral National and Doctoral theCONICYT/FONDAP CONICYT/FONDAP Scholarship, FONDECYT CEDEUSProject CenterN DoctoralScholarship, Scholarship,FONDECYT FONDECYTProject ProjectN N º 1130305 and the CEDEUS Center N º 1130305 15110020.and the CONICYT/F WeWe gratefully thank thethe peer-reviewers forfor their comments and suggestions. Nº 15110020. gratefully thank peer-reviewers their Nºvaluable 15110020. valuable comments We gratefully and thank suggestions. the peer-reviewers for their valuable comments and

Interest: authors declare of nointerest. conflict of interest. Conflicts ofConflicts Interest:of The authorsThe declare no conflict Conflicts of Interest: The authors declare no conflict of interest.

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