تحليل تغييرات تابش فرابنفش در منطقه‌ي اصفهان

Analyzing the Variations of Ultra Violet in Esfahan Area

براي بررسي تابش فرابنفش و تحليل زماني آن در سطح كشور، ايستگاه اصفهان، به لحاظ داشتن اتمسفري همگن، به منزله‌ي مدلي براي كل كشور انتخاب شد. براي تحليل زماني داده‌ها نيز، دوره‌ي آماري از سال‌هاي 1380 تا 1390 تهيه گرديد. بررسي داده‌ها به صورت چهار واحد زماني متفاوت روزانه، ماهانه، فصلي و سالانه با استفاده از روش‌هاي آماري و آزمون من‌ كندال انجام گرفت. نتيجه‌ي بررسي‌ها در ايستگاه اصفهان، نشان داد كه بيشترين شاخص تابش فرابنفش به مقدار 11/5 است كه معمولاً در اواسط تابستان روي داده و كمترين آن به مقدار 5/0 در اواسط زمستان اتفاق افتاده است. همچنين، نتايج حاصل از برازش خط روند تغييرات فصلي براي دهه‌ي اخير، نشان داد كه مقدار تابش در بهار روندي افزايشي داشته و براي ديگر فصل‌ها اين روند كاهشي بوده است. از طرفي نيز، بيشترين تابش آفتاب بين ساعت‌هاي 10 صبح تا 16 بعد از ظهر بوده و در بيشتر اوقات سال، شاخص از 3 بالاتر بوده است. در نتيجه‌ي اين امر، مردم بايد اقدامات پيشگيرانه را رعايت كنند تا از صدمات ناشي از آن در امان بمانند.

Ultra violet radiation has some useful effects and some harmful effects on human health an d create many diseases. Nowadays not only declined but the usefulness of the therapeutic effects of the Sun in the treatment of diseases such as rickets, psoriasis and eczema have been proved. But prolonged exposure to radiation of the Sun is not always beneficial and may cause acute and chronic effects on the health of the skin, eyes and immune system. Ultraviolet radiation of the Sun is one of the most destructive waves for life on Earth. So Ultraviolet radiation index and predict its rate (1 to +11) as well as the analysis of this indicator will help people to protect themselves against the Sun Ozone station , global ozone measurement stations and only stratosphere in Isfahan, Iran, which is in the South and in the Northern geographical position latitude 32' 31 and 70 ' 51 is located over the East. The altitude of this station from sea is 1550 m. Also atmospheric parameters in this station which are measured daily include temperature, pressure, humidity, wind speed and direction and in the upper levels of the atmosphere at 12 GMT with the help of Joe's high temp radio instrument. The first step to do this research was gathering of climatic data and the statistical and quantitative analysis in order to study on the subject. Ultraviolet radiation data on the same basis of assessment, ozone station during the period January 2001-December 2010 has been collected. The second batch of data information gathered from meteorological station of Isfahan climatic elements from 2001 to 2010. This data is based on monthly averages for analysis of solar UV radiations from meteorological solidarity with the country. Adjust the time series at the first step in the study and analysis of the data was done in order to equal intervals in these regular categories and methods of statistical analysis was carried out on them and the overall process of UV changes in the form of daily, monthly, quarterly and annually. Also part of the analysis that was carried out on the data, check how the sequence or they had over time; this way specify whether data periodically changes or trends have been or not. Once the data is based on the time of occurrence, sort and arrange the time series on them. Annually analysis of UV index showed the general variation is a common feature of studied years but in the spring season have high variation in compared with other season. The main reason of this variation may be related to sunlight angle that can be showed atmosphere effect on received radiation. Descriptive statistic result indicated that the highest mean of UV index is 6.52 and minimum were 4.8 that have very high variations and may be it has different harmful effects. Also seasonal analysis showed highest UV index created in hot summer related to highest temperature in this season. The computational modeling of UV index against years in different season indicates there do not exist a linear relation between two factors. The correlation analysis of UV index and some climatic factors showed there are a significant relation between temperature with 0.8570 coefficient that can be said in relation to increase of temperature, UV rate increased and vice versa and with cloud cover correlation coefficient is -0.393 that have significant negative relation. Results showed that the peak time period are output in the first half and the second half of the year, landing in the specified time series. As well as through a linear fit to all charts, increase or decrease of the radiation, changes the trend in recent years, showed that based on the ultraviolet radiation changes the average increase in the spring and summer and fall and winter shows a decline. Also according to the ultraviolet radiation in daily statistics review ozone assessment station in the studied period (2001-2011) maximum amounts of ultraviolet radiation index, (11.5) observed in the middle of the summer and the minimum amounts of radiation index (0.5) observed in mid-winter.