In this study, the results of erythemal UV and UV index measurements obtained by Eppley UV radiometer, UV-AB radiation data and UV sensors since 1993 are discussed. UV measurement tools are located at 'Cukurova University Space Sciences and Solar Energy Research and Application Center' at an altitude of ~ 130 m, at 37 degrees 04' North Latitude and 35 degrees 21' East Longitude. In the article, the data recorded in 2013, 2014, 2017, 2018, 2019 were analyzed. Unfortunately, most of the data for 2015 and 2016 could not be used for analysis due to the corruption of the recording disk. In the study, data recorded as 1636 days, approximately 196320-5 minutes were analyzed. Hourly and daily UV dose, UV index, humidity, and temperature values were created from the recorded data of 5 minutes. In addition, the ozone values (Dobson Unit) obtained from the Tropospheric Emission Monitoring Internet Service (TEMIS) and measured for the city of Adana were compared with the UV radiation values reaching the surface. (http://www.temis.nl/uvradiation/UVarchive/stations_uv.html). Thus, the correlation results between the measured and calculated data and the data obtained from TEMIS were compared and it was determined that there was a considerable consistency between each other.
2.1. UV Dose
196320 five-minute average (UV dose and UV index) data were divided into two parts as May-August and annual averages. Firstly, the changes in UV radiation values during the months of May, June, July and August, when the sunshine duration is more, and secondly, throughout the year were examined. The change in the total UV dose value of 1636 days between 2013 and 2019 is given in Figure 1.
Adana is a region where both agricultural areas and summer holiday activities are intense. Agricultural workers work in very thin clothes or half-naked. With the onset of summer vacation, people are sunbathing almost every hour to get suntan, despite all warnings. Therefore, people in this area are exposed to severe UV radiation. In Table 1, the total daily mean UV dose (MED) calculated in May, June, July and August and the graph of this table are given in figure 2.
Table 1
Total UV Dose (MED) between the years 2013-2019
Years
|
May
|
June
|
July
|
August
|
2013
|
12.50
|
13.90
|
14.10
|
11.80
|
2014
|
10.61
|
12.19
|
11.81
|
11.20
|
2017
|
11.88
|
15.88
|
16.31
|
13.10
|
2018
|
13.41
|
15.73
|
18.15
|
16.50
|
2019
|
14.89
|
15.78
|
17.65
|
15.72
|
As can be seen from Table 1, the average UV dose values for the months of May, June, July, and August are different during the years 2013-2019. However, when both tables are examined, the 4-month average dose amounts decreased in 2014. However, from 2017 to 2019, increases are observed in all 4 months. The largest increase was calculated in 2018. It was calculated that the average increase in July reached a maximum value of 18.15 MED (3811.5 J/m2). This increase continued in 2019 and the measured average UV dose value was calculated as 17.65 MED (3706.5 J/m2). When the change in July is taken into account, the increase that started in 2017 reached its maximum in 2018, and in 2019 slightly began to decline. In Figure 2, the average values of 4 months and standard deviation values of the data taken during the years 2013-2019 are given on the graph. The UV dose obtained from the averages of the 4 months selected between 2013-2019 was calculated as 14.16 MED or 2973.6 J/m2.
In Figure 3, the annual mean and standard deviation values of the 4 months are given on the graph. As can be seen from the figure, the increase continues based on the data for the year 2014. The mean dose values of the last three years were 14.29, 15.95, and 16.01 MEDs, respectively.
Table 2
Daily UV Dose frequency distribution in May-June-July August during the period 2013-2019.
Years
|
N of D
|
Low
|
Mid.
|
High
|
V.High
|
Extreme
|
Total %
|
2013
|
123
|
0
|
0.02
|
0.06
|
0.37
|
0.55
|
1.00
|
2014
|
98
|
0
|
0.01
|
0.10
|
0.73
|
0.16
|
1.00
|
2017
|
123
|
0
|
0.05
|
0.05
|
0.21
|
0.69
|
1.00
|
2018
|
123
|
0
|
0.00
|
0.03
|
0.08
|
0.89
|
1.00
|
2019
|
114
|
0
|
0.00
|
0.02
|
0.13
|
0.85
|
1.00
|
Average
|
116.2
|
0
|
0.02
|
0.05
|
0.30
|
0.63
|
1
|
2.2. UV Index
The instantaneous effect of UV light is also extremely important. The UV index tells us the effect value of the instantaneous UV radiation. One of the results obtained in this study is the instantaneous UV index. The percentage frequency of the UV index between May and August was determined during the years 2013-2019. In Table 3, UV index percentage frequencies are given according to the values accepted by the WHO determined in this study.
Table 3
During the years 2013 -2019, UV index instantaneous frequency distribution between May and August.
Years
|
Months
|
N of D
|
Low
|
Mid.
|
High
|
V.High
|
Extreme
|
2013
|
May to Agust
|
25092
|
0.477
|
0.279
|
0.241
|
0.003
|
0
|
2014
|
May to Agust
|
20046
|
0.501
|
0.266
|
0.225
|
0.009
|
0
|
2017
|
May to Agust
|
25092
|
0.489
|
0.273
|
0.233
|
0.004
|
0
|
2018
|
May to Agust
|
25092
|
0.509
|
0.263
|
0.225
|
0.004
|
0
|
2019
|
May to Agust
|
23333
|
0.484
|
0.272
|
0.242
|
0.003
|
0
|
According to the WHO UV index scale, it was determined that the instantaneous UV index value in Adana region has a very high value between 6 and 10 in total. As expected, this frequency is greater between the hours 10.00 and 14.00. In Table 4, the percentile frequency of the hourly UV index between May and August is given. As can be seen from both tables (3&4), the extreme value is not reached in the UV index. This is thought to be due to the diffusion of UV light resulting from high humidity.
Table 4
Instantaneous UV index frequency distribution between 10.00-14.00, between May-August during the years2013 -2019.
Years
|
hours range
|
N of D
|
Low
|
Mid.
|
High
|
V.High
|
Extreme
|
2013
|
10-14
|
7380
|
0.036
|
0.144
|
0.192
|
0.628
|
0
|
2014
|
10-14
|
5880
|
0.061
|
0.133
|
0.288
|
0.517
|
0
|
2017
|
10-14
|
7380
|
0.059
|
0.231
|
0.399
|
0.31
|
0
|
2018
|
10-14
|
123
|
0.05
|
0.145
|
0.222
|
0.584
|
0
|
2019
|
10-14
|
6859
|
0.04
|
0.121
|
0.267
|
0.572
|
0
|
According to the criteria determined by WHO (6-10 UV index), the instantaneous effect percentage of the UV index varies between 70%-83% between 10-14 hours (high + V High).
2.3. UV Dose-Ozone relationship
The ozone-UV radiation relationship was another result of this study. In this study, Ozone exchange from TEMIS was also investigated. The relationship between ozone and UV was compared with the average of the months of May-August and the average of the measurement years. The changes in ozone values are given on the graph in figure 4. In Figure 4, it is seen that ozone exchange decreases almost every month (May-August). It can be observed that the UV dose increases in response to the decrease in ozone.
The correlation between ozone and UV dose in Figure 4 was found to be R= -0.64. It can be observed that there is a negative relationship between ozone and UV dose, although not very strong, as expected, the UV dose increases as ozone decreases. While the average value in UV dose was a maximum 15.60 MED in July, the average value of ozone was determined to be a minimum 295.16 DU. In May, the average value of UV dose is a minimum 12.66 MED, while the average value of ozone is a maximum 333.79 DU. These changes can be explained by the expansion of the atmosphere and the onset of thinning of the ozone layer, with the increase in the tilt of the earth and the atmospheric temperature. The effect of anthropogenic gases on ozone with the release of anthropogenic gases into the atmosphere can be seen in annual averages. In Figure 5, annual averages are shown on the graph.
As seen in Figure 5, while the ozone amount was low (308.9 DU) in 2013, the UV dose was high (13.08 MED). In the year 2014, there seems to a recovery in the ozone. It can be observed that while the amount of ozone was 315.9 DU, that of UV was 11.45 MED. In 2019, the decrease in the amount of ozone was 304.40 DU, while the ozone value increased (16.01 MED) as expected. The correlation coefficient between the annual UV and Ozone average data measured during 2013-2019 was found to be -0.86. This negative relationship can be easily seen from the figure. The result of the analyzed data states that while ozone decreases, UV radiation increases (Baldermann et al., 2019, Pastukhova et. al., 2019).
The average values of the 12 months between 2013-2019 are given in figure 6 on the graph. As can be understood from these average values, the ozone amount started to decrease from March to October. On the other hand, there are two reasons for the increase in UV radiation. The first is the axial tilt of the earth. Towards and during the summer months, the duration of sunbathing increases, causing more UV radiation to reach the surface. The second reason is that with the increase in temperature, the ozone layer begins to thin between these months. (David et al., 2015).
2.4. Comparison of Data
One of the findings obtained in this study is the relationship between UV dose, ozone, temperature and humidity. The average values of the data obtained between 2013-2019, for the months of May, June, July, and August are given in Table 5. The correlations of the mean values of these months with each other are also given in Table 6.
Table 5
Average OZONE, UV Dose, Temperatur, Humidity, change from May to August between 2013-2019.
|
May
|
June
|
July
|
August
|
UV Dose
|
12.66
|
14.70
|
15.60
|
13.67
|
OZON
|
333.79
|
312.95
|
295.16
|
292.51
|
Temp.
|
22.33
|
24.89
|
27.61
|
28.17
|
Hum.
|
57.17
|
60.12
|
58.55
|
58.38
|
Table 6
During the years 2013-2019, May - August between the measured ozone, UV Dose, Temperature, Humidity Correlation Between Value.
Data
|
R
|
UV Dose- Ozone
|
-0.64
|
UV Dose-Temp
|
0.60
|
UV Dose-Hum.
|
0.65
|
Ozone -Temp.
|
-1.00
|
Although the correlation value R= -0.64 between UV dose and ozone is not very strong, it means that as ozone decreases, UV Dose increases. Similarly, there is a positive ratio of 0.60 between UV dose and temperature. Although it is not a very strong ratio, it can be stated that the temperature increases as the UV radiation increases. Similarly, there is a positive increase between UV Dose and Humidity (R=0.65). It can also be stated that the UV ray diffuses owing to humidty. The most surprising finding is the negative relationship between Ozone and Temperature (R=-1.00). It indicates that the negative relationship causes the ambient temperature to rise due to the ozone depletion of UV rays passing through the atmosphere.