Introduction

Urbanization has gained pace and momentum in recent decades all over the world including Turkey. This is due to the rapid developments in technology, the increase of transportation facilities and so on. This has resulted in destabilizing the ecological balance in urban areas (Bakhtiari & Bakhtiari, 2013; Bode et al., 2003; Cetin, 2015; De Freitas, 2003; Hamilton & Tol, 2004; Harlfinger, 1991; Kaya et al., 2019; Scott & Lemieux, 2009; Wang et al., 2016). The natural areas in the city are replaced by stone and concrete structures, and the natural land cover (forests, pastures, streams, ponds, etc.), which we call rural areas, are pushed further away from the city center with time. More industrial, transportation, and shopping services are being developed to serve the spatially growing city. Horizontal and vertical structures arranged side by side have negative effects on temperature, relative humidity, wind and precipitation, and distinguished the urban climate from its environment (Adiguzel et al., 2020; Amelung et al., 2007; Amelung & Viner, 2006; Clements & Georgiou, 1998; De Freitas, 2003; Farajzadeh & AhmadAbadi, 2010; Fielding & Shortland, 2011; Fletcher & Morakabati, 2008; Grassl, 1976, 1979, 1981, 1989, 2006, 2011; Gungor et al., 2021; Zeren Cetin et al., 2020; Zeren Cetin & Sevik, 2020; Zhong & Chen, 2019).

According to the research, it shows that the average annual temperature increases by 2–3 °C compared to the rural environment of cities. This temperature value reaches 5–13 °C, depending on the spatial size of the city, the presence of industry, the excess of motor vehicles, and the insufficiency of green areas (Ataei & Hasheminasab, 2012; Auliciems & Kalma, 1979; Bozdogan Sert et al., 2021; Hejazizadeh et al., 2019; Hernandez & Ryan, 2011; Kovács & Unger, 2014a, b; Lei et al. 2013; Maddison, 2001; Matzarakis, 2002, 2006, 2007; Méndez-Lázaro et al., 2014; Mieczkowski, 1985; Moreno et al., 2008; Scott et al., 2004, 2016; Scott & Lemieux, 2009). Because the high-rise and dark-colored buildings in cities, floors covered with asphalt and concrete, the temperatures from urban heat islands also high-rise buildings which block wind paths and prevent wind circulation within the area are the reasons for the warming of cities.

When the difference in the climate of cities reaches extreme values, it brings negative effects on human health. These effects limit the mental, physical, and biological activities in activities of human beings. Too hot, cold, and excessive humidity are undesirable due to the difficulty of adaptation for people. Owing to the difficulty of adaptation, too hot, too cold, and excessive humidity are undesirable for people (Olgyay, 1973). According to Olgyay (1973), the condition in which the necessary climatic conditions (temperature, relative humidity, wind, and precipitation) coexist with the human being is called bioclimatic comfort (Berrittella et al., 2006; Cetin, 2016, 2019, 2020a, b; De Freitas, 2003, 2005; Lin & Matzarakis, 2008; Scott & Lemieux, 2009; Scott & McBoyle, 2001).

The geometry of the city affects the bioclimatic comfort areas and creates urban heat islands. According to Oke (1981), urban heat island formations generally occur at night. While it has a positive effect in winter, it is observed that temperatures increase excessively in summer months (Canan, 2017; Cetin, 2016, 2019, 2020a, b).

Many studies indicate that urban forests, green spaces, and roofs, regular urban uniforms have a significant impact on the reduction of urban heat islands (Amiranashvili et al., 2008, 2010, 2018; De Freitas, 2003; Lin & Matzarakis, 2008; Lise & Tol, 2002; Scott & Lemieux, 2009; Zhong & Chen, 2019). As the number of green areas in the city increases, the positive effect on the temperature increases. In the study conducted by Monteiro et al. (2016), the city of London was selected, and the correlation between green areas and night temperatures was studied.

In this study, a narrow study area was selected in the Adana-Cukurova district. The urban form in the study area, the structure of buildings and ground areas, and the presence of green and open spaces investigated the amount of the bioclimatic comfort areas. For this purpose, a study was carried out on Hayal Park, which has the densest urban structures of the Cukurova district and its surroundings and on some streets.

Material and methods

The study area was the Hayal Park and its surroundings in the Toros Quarter of Cukurova District, which is surrounded by multi-story and dense buildings in the north of Adana (Fig. 1). Although the vertical construction is very high, it is richer in terms of green areas compared to other large central districts. Cukurova, which is one of the largest districts of Adana (according to population), has Seyhan dam lake in the north and Seyhan district in the south. The study area is on the border of Seyhan district and is adjacent to Yüreğir and Sarıçam districts.

Fig. 1
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Work area location map

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With the portable Smart SENSOR AS 847 measuring device, temperature and relative humidity were measured at 1.5 m above the ground on Tuesday, August 20 at 07.00, at 14.00, and 21.00. Bioclimatic comfort areas were determined by measuring temperature and relative humidity at 25 points with different textures in the study area.

In this study, measured instantaneous temperature (°C) and relative humidity (%) data were transferred to GIS medium by ArcGIS 10.6 program and then modeled with the Kriging method, which is one of the interpolation methods, and temperature and relative humidity maps were created. The temperature map created in degrees Celsius (°C) by the Kriging method and was converted to Fahrenheit degrees (°F) in the Raster Calculator. The reason for this change is that SSI is calculated with the formula Fahrenheit (°F). These maps were then calculated on the Raster Calculator using the SSI formula, and sensed temperature values were obtained (Pepi, 1987).

$$\begin{aligned}SSI\;Formula=1.98&[Ta-\left(0.55-0.0055Ur\right)\\&\left(Ta-58\right)]-56.83\end{aligned}$$

In this index formula, Ta represents air temperature Fahrenheit (°F) and Ur relative humidity (Tzenkova et al., 2007).

The temperature values were converted to degrees Celsius (°C) for a better understanding of the maps. According to the SSI given in Table 1, thermal comfort values were determined and classified. The classification table was adapted to the SSI values created by analyses and calculations, and thermal comfort classes were created (Tzenkova et al., 2007).

Table 1 Classification of thermal comfort is that prepared from Pepi (1987)
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Results

Residential areas and land cover

In recent years, as a result of rapid population growth and unplanned growth models in many cities, green areas have decreased; climatic changes have been experienced and adversely affected urban comfort and ecosystem (Matzarakis & Endler, 2010; Topay, 2012). Adana was affected by these problems, and uncomfortable areas increased throughout the city center. When we look at the study area, in particular, the Cukurova district has become a settlement, where rapid population growth, rapid urbanization, and other developments related to these have caused many environmental problems, and the proper use of natural values has been restricted. With the development plan prepared in 1985, the development of high-density vertical constructions started in Northern Adana and gained speed. Nowadays, it is seen that almost all of Northern Adana is surrounded by multi-story buildings (Fig. 2), which causes the city to be much hotter in the summer months, and the temperature is extremely high due to the humidity.

Fig. 2
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3D view of the workspace

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Floor heights are highly effective in weather temperatures, especially in terms of changing wind directions and storing temperatures due to surface characteristics and the spatial size of the city, causing cities to warm up (Oke, 2004). When we look from this perspective, the distribution and proportions of the building floors in our study area are different. The number of floors ranges from 1 to 19 (Fig. 3). In non-buildings, there are green spaces and a small number of empty spaces. Although building heights may harm urban temperature, this effect may vary due to factors such as street-to-street widths and various urban forms.

Fig. 3
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Building floor numbers

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Temperature and relative humidity

Mobile measurements performed in the study area were carried out on Tuesday, August 20 at 07.00 in the morning, at 14.00 in the afternoon, and 21.00 in the evening. As a result of these measurements, significant differences were found in temperature and humidity values.

According to the temperature maps prepared within the scope of this study; temperatures range between 24 and 28.5 °C in the morning, 31–35 °C in the noon, and 27–34.5 °C in the evening. While lower values were observed in the west, the highest temperature values in the mobile measurements were found in the east and many places (Fig. 4). This difference in temperature distributions between morning, noon, and evening can be explained by the differences in building height and the presence of light-green areas. It is seen that the temperature values of Hayal Park which is located to the west of the study area are the lowest. It has been determined that the temperatures are quite high in places where floor heights are dense and in narrow streets.

Fig. 4
figure 4

Working area temperature maps of the study area

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When we look at relative humidity maps, humidity ranges between 70 and 80 °C in the morning, 38.8–47.33 °C at noontime, and 56.89–64.5 °C in the evening (Fig. 5). The highest relative humidity values are observed in the morning, and the lowest values are at noon. When we compare the temperature and relative humidity maps, we see that the values are inversely proportional. Relative humidity values are the lowest at noon when temperature is the highest. This is since the temperature increases this month, allowing the air to expand and the rainfall does not fall. In this way, in the summer season, high relative humidity, which does not turn into precipitation, is over 50% but not 100% in the morning and evening hours and causes a sweltering air.

Fig. 5
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Working area relative humidity maps of study area

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Discussions

Felt temperature and bioclimatic comfort

In many climate indices, temperature, humidity, and wind values are sometimes evaluated by applying different combinations to determine bioclimatic comfort areas. The most sensible temperature criterion is used to determine the areas of bioclimatic comfort. The sensed temperature can be defined as the temperature that a person feels or perceives, unlike normal air temperature. Accordingly, temperature and relative humidity maps made for the study area, SSI formula (SSI formula = 1.98 [Ta − (0.55 − 0.0055 Ur) (Ta − 58)] − 56.83) felt temperature maps were created (Pepi, 1987). In this formula, the temperature values are calculated as °F. The temperature map in °C was converted to °F with ArcGIS Raster Calculator for formula application. The temperature and relative humidity of the study area were obtained by the SSI formula. When this map is examined, the sensed temperatures vary between 31.88 and 38 °C in the morning, 38.92 and 43 °C in the morning, and 34.72 and 43.65 °C in the evening (Fig. 6). This means that bioclimatic comfort areas cannot be determined by simply looking at temperature maps.

Fig. 6
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Felt temperature maps made with SSI formula

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The temperature values felt in the study were calculated with the SSI formula, and then the maps of the study area were classified. The SSI, which normally has 8 classes, has 3 classes in the study area. These classes are 83 ≤ SSI < 91 slightly hot, 91 ≤ SSI < 100 hot, and 100 ≤ SSI < 112 very hot (Fig. 7). When we look at the maps, the places outside of Hayal Park are in the hot class at 07.00 in the morning, and we can see that the green spaces have a positive effect on the bioclimatic comfort areas. The small area is in a very hot class. When we look at 14.00 h, it is a totally hot class. Normally, the temperature is the highest of these times and also coincides with the multi-story buildings in the study area; asphalt and concrete areas increased the temperature. As a result, there is a sweltering air in the work area.

Fig. 7
figure 7

Workspace new summer index (SSI) classification

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In settlements like Cukurova, because of the high temperatures in the summer months, the urban heat islands emerge, and in this case, there are problems in terms of bioclimatic comfort and health conditions for the people living in Cukurova.

Conclusions

It was determined that the maps identified non-comfortable areas. It was observed to be in little hot, hot, and very hot categories. According to the results of the map, it is seen that the lowest temperature values are 31.88 °C, and the highest is 43.65 °C. Since urban form and settlement affect climate comfort values, the urban plan should be revised, and the area should be brought to the bioclimatic comfort value range. One of the most important factors for reducing the effect of temperature in the working area and creating comfortable areas is increasing the density of green areas compared to asphalt and concrete areas. Green spaces provide cooling effect, thanks to plants, and reduce the urban heat island formation. Considering that the Cukurova district will grow further, urban planning should be done very well to reach the comfort range in the following settlements.