مطالعه كارايي مدل اقليم منطقه اي (RegCM ) در شبيه سازي داده هاي دما و بارش برخي شهرهاي منتخب ايران مطالعه موردي : دوره 2015-2010

Investigation of the efficiency of Regional Climate Model (RegCM 4.3) in simulation of temperature and precipitation data in Iran during 2010-2015

در تحقيق حاضر با استفاده از مدل اقليم منطقه اي ( RegCM )، اقليم ايران براي دوره زماني شش ساله (2015-2010) شبيه سازي گرديد. بدين منظور، از طرحواره Kiehl براي تابش، از طرحواره تبادل زيست‌كره - هواكره (BATS) براي سطح خشكي، از طرحواره Holstlag براي لايه مرزي سياره‌اي و طرحواره Emanuel براي بارش همرفتي استفاده شده است. هشت ايستگاه هواشناسي از نقاط مختلف ايران از طريق نمونه گيري تصادفي به روش خوشه اي انتخاب گرديد. در مرحله بعد داده‌هاي مربوط به دما و بارش روزانه از پايگاه داده‌هاي باز تحليل ERA -Interim براي دوره ي زماني مذكور استخراج گرديد و سپس ميانگين ماهانه مقادير به دست آمد و با سري داده‌هاي حاصل از شبيه سازي مدل اقليم منطقه اي (RegCM) مقايسه گرديد. براي فراسنج (پارامتر) دما، شبيه سازي با مدل، مقداري بالاتر(ميانگين 2 درجه سانتيگراد) از مقادير بازتحليل (ERA-Interim) را نشان داد. براي پارامتر بارش با توجه به ماهيت اين كميت (ناپيوسته بودن) مدل اقليم منطقه اي نسبت به پارامتر دما دقت پايين‌تري داشت. مقادير شبيه سازي شده بارش براي شهر هاي پر بارش مثل بندر انزلي پايين‌تر 257 ميليمتر (15 درصد) و براي شهر هاي كم بارش مانند يزد و زاهدان، بالاتر از مقادير باز تحليل به ترتيب 38 ميليمتر (57%) و 58 ميليمتر (72%) و براي شهرهايي مثل زنجان اين دو مقدار نزديك به هم به دست آمد. مدل به خوبي ماه هاي پر بارش و كم بارش را از همديگر تفكيك نمود بطوري كه همخواني دو سري داده در اكثر ايستگاه ها كاملاً مشهود است. به طور كلي، مدل اقليم منطقه اي به عنوان روشي مناسب در شبيه سازي داده هاي دما و بارش توصيه مي گردد.

Introduction: The climate of the earth has begun to warming since 1980’s which has created very serious problems for the human living and natural environment. As a result the study of the global warming and its solutions has become the focal point of the climate change research all over the world. The climatologists are trying to understand, predict and finally give solutions to it. Many different models have been developed to predict and project the future climate conditions among which the Regional Climate Model is to some degree has lower values of uncertainty. The impacts of climate change is relatively higher in the naturally dry climate of the Middle East including Iran. Here the main parameters of the climate that is temperature is increasing and precipitation decreasing. As a result the projection and understanding of these two elements are very important for the region and Iran. For this reason this studyhas focused on the efficiency of the Regional Climate Model in projecting the future climate of the region and Iran. Data and Methods: In order to test the efficiency of RegCM 4.3the monthly temperature and precipitation Data were extracted for the window 24N-40N and 43E-64E from the ECMWF database with spatial resolution of 2.5 degrees. These data were compared and corrected with the station data of Bandar Anzali, Bandar Boushehr, Mashad, Tehran, Yazd, Zahedan, Khorramabad and Zanjan . The simulated model data for RegCM 4.3were extracted for the same period and area with the same spatial resolution. Both data were transported into the Matlab environment and compared. Results and Discussion: Results of simulated RegCM 4.3data were compared withobserved data of eight stations. The temperature data were slightly (about 2 degrees C) more than observed data. But the precipitation projections were somewhat complicated. The values of rainy stations such as Anzali were overestimated ( about 257 mm) while that of most dry stations such as Zahedan were underestimated (about 58 mm). But the RegCM 4.3 simulations were the same as the observed data inthe normal stations such as Zanjan. The results showed that the RegCM 4.3is suitable for projecting temperature data more than the precipitation. This is in agreement with the findings of many other studies.