ASSESSMENT OF BIOCLIMATIC COMFORT ZONES USING THE RAYMAN MODEL: A CASE STUDY OF SULAIMANI – IRAQ

This study is conducted to retrieve bioclimatic comfort zones for outdoor recreation planning in Sulaimani province, Iraq. Spatial distribution of Physiological Equivalent Temperature (PET), which is a measure of bioclimatic comfort, was retrieved for the city of Sulaimani using meteorological data. The air temperature, relative humidity and wind speed data were employed for the calculation of PET. Data recorded at 15:00 obtained from 7 meteorological stations over the period from 1992-2015 were used to calculate monthly PET with the Rayman model. PET was spatially interpolated using IDW tool in ArcGIS 10.2 to convert point-data consisting of PET for each individual meteorological station into a continuous surface. Therefore, spatial distribution maps of PET for outdoor recreation activities were created after analyzing the maps. The results revealed that the lowest PET determined was around 4.8°C in Penjwin area during January while the highest PET determined as 59.6°C in northeast of Sulaimani, Halabja during July. On the other hand, the results also revealed that Sulaimani city, Dukan and Penjwin areas are founded to be more suitable for tourism especially during summer months compared to others within Sulaimani Province. The final results of this study may be used by recreation authorities in Sulaimani in the near future.


INTRODUCTION
Climate and atmosphere influence humans' well-being and prosperity. This study incorporates the meteorological parameters of air temperature, relative humidity, and wind speed, which influence human being thermo-physiologically in indoor and outdoor.
Outdoor bioclimatic comfort is influenced by the microclimatic conditions, particularly air temperature, relative humidity, wind speed and radiation fluxes, by a set of personal parameters, such as physical activity, type of cloth and age, and also by psychological factors, namely motivation, individual preferences and cultural aspect. (Nikolopoulou and Steemers, 2003;Stathopoulos et al. 2004;Knes and Thorsson, 2006).
Unfortunately, data on several of these parameters, such as short and long wave radiation, are generally not available in meteorological records. As a result, climate assessments and thermal comfort studies have often resorted to the use of climate indices without these key factors. For example, IPCC (2001), describes the effect of weather and climate on humans with a simple index based on a combination of air temperature and relative humidity. The exclusion of important meteorological data (wind speed and radiation fluxes) and thermo-physiological (activity of humans and clothing) variables seriously diminishes the significance of the results.
The main objectives of this study are to:  Calculate PET values through Rayman Model.  Create a map for Sulaimani City, Iraq using GIS.  Determine the thermal comfort zones for outdoor recreating planning in Sulaimani City, Iraq.  Provide information to recreation planners in Sulaimani City to retrieve the optimal months suitable for visitors.

Study Area
Sulaimani city is located in the northern part of Iraq. It is situated between latitudes (35° 37′ 36″, 35° 28′ 08″ N) and Longitudes (45° 17′ 57″, 45° 29′ 56″ E). It shares border with Iran to the northeast, Erbil to the west and Kirkuk Governorate to the south as illustrated in Figure 1. Sulaimani governorate has an area of 11789 km 2 . The study area is characterized by a Mediterranean climate. According to Koppen classification it is classified as type CSA, which is characterized by warm and dry summer, wet and cold winter. There are two short seasons (spring and autumn) between winter and summer with moderate climate conditions and a maximum temperature 23°C. Summer lasts from the beginning of May to the beginning of October and winter extends from November until the start of March. In winter, especially in January, the temperature decreases to 5°C or even less than -1°C.The highest temperatures, ranging between from 45°C to 48°C, are usually recorded between June and September. Much of the precipitation occurs from November until April. Generally, the annual precipitation of Sulaimani city is (648 mm). However, this has decreased in recent times due to climatic and environmental changes (SWSD, 2015; Wikipedia, 2020), Summer and winter seasons in Sulaimani are illustrated in Figure 2 below. According to RIMP (2015) the population was 1.93 million with annual growth rates of 3% in 2015. In 1987, 63 % of its population lived in the urban centers while 37% lived in the country sides.
In the year 2008, urban population increased to 78% while the rural population dropped to 22% and the rates of urbanization was 3%. This indicates that a rapid rate of rural to urban conversion occurred in the last two decades,

Input Data
In the present study, the meteorological data of 7 synoptic stations over a 23-year time period  were obtained in a quality controlled format from the Meteorological Organization of Sulaimani as illustrated in Table 1 below. The selected stations for this study have complete 23 years records, representing a good spatial distribution over elevation ranges in Sulaimani as shown in Figure 3 below.  The values of air temperature, relative humidity and wind speed were collected from each synoptic station to obtain the mean monthly values of Physiologically Equivalent Temperature (PET) in the Rayman Model.

Rayman Model
The Rayman model which developed according to Guideline 3787 of the German Association of Engineers (VDI 1998) calculates the radiation flux in simple and complex environments on the basis of various parameters (Matzarakis, et al. 2007). The final output of this model is the calculated mean radiant temperature, which is required in the energy balance model for humans. Consequently, it is also required for the assessment of bioclimatic comfort indices, such as Predicted Mean Vote (PMV), Physiologically Equivalent Temperature (PET), and Standard Effective Temperature (SET) as seen in Figures 4 and 5. PET is a thermal index that is used for the estimation of the thermal component for a given environment. The PET allows humans to predict their thermal perception of weather conditions. Therefore, analyzing thermal adaptation characteristics and comfort levels of residents from different regions is quite important to adequately describe the perception of these people (Lin and Matzarakis, 2008). PET can be employed for both indoor and outdoor environment which can be calculated with the bioclimatic model of Rayman.
It is necessary to determine all meteorological variables that are important for the human energy balance to calculate PET. These variables include air temperature (Ta), vapour pressure (VP), relative humidity (RH), wind velocity (v), mean cloud cover (C) and mean radiant temperature (Tmrt). Human parameters influencing PET, such as activity, heat resistance of clothing, height, and weight are usually standardized in MEMI (Matzarakis, et al. 2010). In order to quantify the perception of the thermal environment by humans, threshold values for PET have been developed, which indicate different levels of thermal stress in the form of a graded index (Matzarakis and Mayer, 1996) as illustrated in Table 2. Threshold values of the PET for different thermal perceptions and levels of thermal stress, related to a metabolic rate of 80W (walking) and a heat transfer resistance of clothing of 0.9 (summer clothing). The calculated PET values referred to a person who is 1.75 m, 75 kg, and 35 years old standing male in the sun.

RESULTS AND DISCUSSION
Monthly PET values were calculated using Rayman model with the inputs of the mean monthly values of air temperature, relative humidity, and wind speed for each station as illustrated in Figure 6 below as the PET values were color coded to reflect the thermal stress by months and weather station. The PET values were also mapped using the values in Table 4 with the inverse distance weighted (IDW) method, generally used as a simple local interpolation technique in ArcGIS (Lo and Yeung, 2002). As a result, the final mean monthly PET maps are illustrated in Figures 7, 8,9, and 10 for the study area. The same map legend is used to allow for a better comparison of the months.  In the spring months, the lowest PET values were obtained in March and highest values were seen in May as illustrated in Figure 6 and Figure 8. Summer months illustrated highest PET values in Sulaimani as seen in Figure 9 above. In fall, lowest PET was seen in November in Penjwen, Dokan and Sulaimani. PET values in September were as high as in summer months as shown in Figure 6 and 10. The final PET values ranged from 4.8 °C to 59.6 °C in Sulaimani. The coldest PET values were observed in Penjwen area during the month of December with 4.8 °C while the highest PET values were observed in Darbandiukhan during the month of July with 59.6 °C.

CONCLUSIONS
The PET is a popular method for the assessment of thermal comfort and thermal stress used by decision makers. The monthly PET values observed in Sulaimani ranged from 4.8 °C to 59.6 °C using Rayman model. The coldest PET values were observed in Penjwen region while the hottest PET values were found in Darbandiukhan region during the summer months. We can conclude that topography is the main reason for the differences in the PET. Urban expansion and urban sprawl are the second reason for PET differences. Water surfaces and green areas can be effective in cooling the city.
In Sulaimani, February, March, November and December were found to be the best suitable months for outdoor activity during the year. January is the coldest month while May through September are the hottest months in Sulaimani. We hope that city officials take these results into account for outdoor recreation planning.

AUTHOR CONTRIBUTIONS
Shakhwan Hama Shareef: Organizing weather data, creating maps, help in manuscript writing. Hakan Oguz: Analyzing weather data using Rayman model and ArcGIS, writing, editing and reviewing the manuscript.