تأثیر تغییر اقلیم بر خصوصیات بارندگی دوره آینده (مطالعه موردی: استان گلستان)

نویسندگان

چکیده

امروزه تغییر اقلیم نه فقط در سطوح مدیریتی مرتبط با منابع آب بلکه در زندگی روزمره انسان‌ها نیز تأثیر آشکاری دارد. بررسی تغییرات متغیرهای کلیدی بارش و دما با در ‌نظر گرفتن اثرات تغییر اقلیم در سال‌های آینده می‌تواند در حل معضلاتی چون خشکسالی،‏ سیلاب‌های ناگهانی و غیره راه‌گشا باشد. در این بررسی از داده‌های خروجی بانک اطلاعاتی واحد پژوهش‌های اقلیمی(CRU)‎،‏ تحت چهار سناریوی انتشار A1،‏ A2،‏B1 و B2 استفاده شده است. این داده‌ها برای پارامتر بارش در دو ایستگاه علی‌آباد کتول و مزرعه نمونه ارتش،‏ به ‌عنوان دو ایستگاه مرطوب و نیمه‌خشک استان گلستان،‏ با روش تناسبی کوچک‌مقیاس شدند و سپس با روش زمین‌آمار IDW(8)،‏ درون‌یابی شدند و در نهایت سری زمانی سناریوی اقلیمی در آینده با روش عامل تغییر محاسبه شد. نتایج حاصله از آن در دوره پایه 2010-1981 و دوره آینده 2040-2011 ارزیابی شده است. نتایج مقایسه میانگین بارش سالانه،‏ نشان از افزایش بارش در ایستگاه علی‌آباد کتول و مزرعه نمونه ارتش به‌ ترتیب حدود 6‎/7 و 73‎/8 درصد است. همچنین انتظار می‌رود در دوره آینده،‏ تعداد رخداد بارش‌های حدی افزایش یافته و بیشترین میزان این افزایش در ایستگاه‌های علی‌آباد و مزرعه نمونه به‌ ترتیب در ماه نوامبر و ژانویه رخ دهد.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of climate change on rainfall characteristics in future periods (Case study: Golestan province)

نویسندگان [English]

  • Dr M. Zakeri nia
  • Behnaz Yazarloo
  • mohammad abdolhoseini
چکیده [English]

Today, climate change has effect not only on the management levels of water resources, but also has some implications in everyday life. Study of changing in key variables of temperature and precipitation with regard to the effects of climate change in coming years can be helpful for solving some problems such as drought and sudden floods. Since others researchers have performed their analysis more than one stationary and just had to show changes in quantity, in this study, we try to consider it by location (region). As well as increasing the number of models and downscaling techniques and the future simulation of periods due to increased uncertainty in the results of climate change, in this study, only a regional model and a downscaling method were used. The purpose of this study is to investigate the effect of climate change on precipitation changes and extreme rainfall events in the next period (2040-2011) in two selected stations in Golestan province. In this study, the data obtained from the database of the Climate Research Unit (CRU), under four emission scenarios A1, A2, B1 and B2 were used. The HADCM3 regional model was used as boundary conditions. This model was released in the fourth assessment report (2007) and widely used for studies around the world. Precipitation data of two weather stations, including Ali Abad Katoul and Mazrae Nemooneh Artesh, as representative of both humid and semi- arid stations in Golestan province, were downscaled by proportional method. Then precipitation data were interpolated using IDW (8) as a statistical method, and finally the time series scenarios of future climate change were calculated by the change factor method. To investigate the number of occurrences of heavy rainfall, the precipitation index greater than 50 mm was considered and for specifying high-risk months in each station, the incidence of extreme rainfall was predicted.
The results show that precipitation changes for both stations in autumn, early spring, winter and late and mid-summer increases. The maximum rainfall in November and January are expected that warns the increased intensity of floods at the beginning of winter. At Aliabad Katoul station with a humid climate, precipitation changes for A1 scenario will occur with more intensity and also more precipitation during autumn and early winter and late summer would be expected. In the most of considered scenarios, increase in seasonal rainfall in the regions is expected in all seasons. The largest increase in precipitation in both stations occurred under the B2 scenario. The number of extreme events is expected will be increased in future periods, as this increase in precipitation of the Ali Abad Katoul station will be happening in late summer and early fall, but in Mazrae Nemooneh Artesh station will be happening in late autumn and early winter. Also, it is expected that the extent precipitation will increase in the future and the highest increase in Aliabad and Mazrae Nemooneh Artesh stations would happen in November and January, respectively. The number of extreme rainfall events (greater than 50 mm) and high precipitation levels increased in both stations; however the rate of average precipitation did not show significant changes. As a result, it can be concluded that the probability of occurrence of more heavy rainfall is high in both of studying stations.
Analyzing the results of the base period 2010 -1981 and the future period 2011 -2040 showed increasing in mean of annual precipitation of Ali Abad Katoul and Mazrae Nemooneh Artesh stations around 7.6 and 8.73 percent, respectively. Also, it is expected that the number of extent precipitation events will increase in future period. The results indicate that climate change could increase extreme events in Golestan province, so that by increasing levels of carbon dioxide, the number of days with precipitation will increase which leads to increase the frequency of flood events in the Golestan province.

station will be happening in late autumn and early winter. Also, it is expected that the extent precipitation will increase in the future and the highest increase in Aliabad and Mazrae Nemooneh Artesh stations would happen in November and January, respectively. The number of extreme rainfall events (greater than 50 mm) and high precipitation levels increased in both stations; however the rate of average precipitation did not show significant changes. As a result, it can be concluded that the probability of occurrence of more heavy rainfall is high in both of studying stations.
Analyzing the results of the base period 2010 -1981 and the future period 2011 -2040 showed increasing in mean of annual precipitation of Ali Abad Katoul and Mazrae Nemooneh Artesh stations around 7.6 and 8.73 percent, respectively. Also, it is expected that the number of extent precipitation events will increase in future period. The results indicate that climate change could increase extreme events in Golestan province, so that by increasing levels of carbon dioxide, the number of days with precipitation will increase which leads to increase the frequency of flood events in the Golestan province.

کلیدواژه‌ها [English]

  • Change Factor-Atmospheric General Circulation Model-IDW (?)-CRU-Climate Change Scenarios.-