آشكارسازي آماري تاثير پديده گرمايش جهاني بر ناهنجاري‎هاي دِبي حوضه رودخانه ارس

Statistically Detectable Effect of Global Warming on the Aras River Flow Anomalies

پژوهش پيش رو براي آشكار‎سازي اثرهاي گرمايش جهاني بر آبدهي حوضه ارس انجام گرفته است. داده‎هاي استفاده شده براي انجام اين پژوهش، شامل داده‎هاي سالانه و فصلي گرمايش جهاني و داده‎هاي دِبي حوضه ارس در بازه زماني چهل‎ساله (2008-1968) بوده و براساس روش‎هاي همبستگي پيرسون و رگرسيون خطي و غيرخطي براي مطالعات فصلي و سالانه به انجام رسيده است. مطالعات نشان از ارتباط معكوس و قوي گرمايش جهاني با آبدهي حوضه ارس دارد. اين فرآيند، به‎خصوص از سال 1994 به بعد آشكار است و با افزايش گرمايش جهاني آبدهي حوضه ارس، كاهش چشمگيري از خود نشان مي‎دهد. تغييرات آبدهي حوضه ارس نشان از روند كاهنده آن طي بازه زماني بلندمدت خود دارد كه ارتباط آن با گرمايش جهاني داراي همبستگي معكوس برابر با 68/0- درصد با ضريب تعيين 46/0 است. در بين فصول سال بيشترين تاثيرپذيري از گرمايش جهاني متعلق به فصل زمستان با همبستگي معكوس 70/0- و ضريب تعيين 49/0 است. فصل بهار با همبستگي معكوس 57/0- و ضريب تعيين 32/0، پاييز با همبستگي معكوس 54/0- درصد و ضريب تعيين 29/0 و درنهايت تابستان با همبستگي معكوس 17/0- و ضريب تعيين 03/0 درصد، در رتبه‎هاي بعدي قرار مي‎گيرند. در تمامي مطالعات انجام گرفته، روند دِبي حوضه ارس همواره كاهنده بوده و از سال 1994 به بعد زير ميانگين بلند مدت خود است كه وقوع خشكسالي و كاهش آبدهي شديد حوضه، درنتيجه تاثير گرمايش جهاني را نشان مي‎دهد. مقايسه مدل‎هاي رگرسيون خطي و غير خطي در شبيه‎سازي تغيير پذيري آبدهي حوضه ارس از گرمايش جهاني نشان از دقت بالاي مدل غير خطي نسبت به نوع خطي خود دارد.

Introduction Evidence of climate change on Earth is the result of human activity. Significant changes in global temperature and climate change or global warming is the most important consideration in the present century. Global warming is primarily the result of large amounts of greenhouse gases into the atmosphere. Among the most affected greenhouse gases in global warming is carbon dioxide, which is caused by the burning of fossil fuels and deforestation; There is clear evidence that we have already seen the concentration of this gasin the last half million years on Earth, which will cause the Earth to become warmer. The Intergovernmental Panel on Climate Change global warming and sea level rise in the 20th century on a 6/0 ° C and 20 cm have been estimated. They also predict that global temperatures between 1/4 to 5/8 ° C and sea levels by the year 2100 will reach 20 to 88 cm. Global warming impact on hydrology and water resources basins, result in the increased risk of flooding, drought and landslides as a result of climate change impact son many physical and biological changes basins will follow. And hence the critical importance of this issue, the present study was designed to detect the impact of this phenomenon on the Aras basin discharge that is considered as an one of the great basin and important country; and discharge changes can be tremendous changes in the morphology change of the river bed and the Iran-Azerbaijan border mobility in the transport and deposition of sediment behind dams etc. should have been done. Methodology For this study, two data set, the data rate of global warming and Aras discharge basin annually and seasonal quarterly data are used. Basin discharge data at Aras 40-year period from year 1968 to year 2008 and the corresponding amounts of data on global warming is taken through the NASA climate prediction center website Www.cdc.noa.gov. First test run quality control tests were performed on the data and homogeneity of the data was ensured.The parameters related to data center trends such as mean, median, range changes, the coefficient of variation, and scenes coefficient kurtosis data was obtained. To determine the relationship between global warming and the Pearson correlation test was used annual rate of Aras discharge; and to predict future changes rate since 2050, exponential regression method was used. Finally, using linear regression and non-linear relationship between the two phenomena of global warming was to simulate the effects of the discharge of the Aras. Results and Discussion Studies show a strong negative correlation between global warming and the Aras basin discharge. Studies such as the annual and seasonal studies of this process can be seen. This process is quite apparent, especially from 1994 onwards, and completely determined dramatically increasing of reduce global warming Aras basin discharge. Aras basin discharge changes during the period of the decline of long-term trends associated with global warming, which is equal to the inverse correlation between 68/0- percentage with a 46/0 Coefficient of determination.In most seasons the influence of global warming is belonging to the winter season with inverse correlation between 70/0-and the coefficient 49/0. Inverse correlation coefficient of spring 57/0- and 32/0 Coefficient of determination, Autumn negative correlation coefficient of the 54/0- and 29/0Coefficient of determination and at the end of summer the reverse correlation coefficient of 17/0- and 03/0 percent Coefficient of determination are in the next rankings In all studies the Aras basin discharge and have been declining since 1994 and is below its long term average, that Severe droughts and reduce the discharge basin show the impact of global warming. Comparison of linear and non-linear regression models in the Aras basin discharge variability of global warming simulations show the high accuracy of the nonlinear model to linear form itself. Conclusion Changes of the Aras basin discharge time series indicate that the downward trend in the basin discharge is the result of global warming. Although the increase and decrease in short-term time series of the show, But in the long run Trend has been declining And especially in the last 15 years as well as annual and long-term seasonal averages were below and With the increase in global warming could decrease excessive discharge areas in the coming years it is undeniable juniper, that This process can be a lot of changes in terms of influence on the morphology.