بررسی طبقه‌بندی اقلیمی کوپن در ‌ایران در سال 1975 و مقایسه آن با خروجی مدل miroc برای سال‌های 2030، 2050، 2080 و 2100 تحت سناریوی a1b و a2 (با تاکید بر مساله تغییر اقلیم)

اقلیم، وضعیتی کلی از شرایط هوای غالب یک مکان مشخص بر اساس آمار بلندمدت است. تنوع عناصر اقلیمی در تعیین اقلیم یک ناحیه موثر بوده و باعث شکل‌گیری اقلیم‌های متنوع و متفاوت می‌شود. افزایش انتشار گازهای گلخانه‌ای و به دنبال آن تغییرات اقلیمی و گرمایش جهانی پیامدهای بسیاری برای کره زمین داشته است. ازجمله‌ این پیامدها، بخصوص برای مناطقی که در کمربند گرم و خشک دنیا قرار گرفته‌اند، افزایش سطح پوشش اقلیم خشک و نیمه‌خشک است. در‌ این مطالعه طبقه‌بندی اقلیمی کوپن برای کشور ‌ایران در سال 1975 با طبقه‌بندی حاصل از خروجی مدل جویاقیانوسی miroc برای سال‌های 2030، 2050، 2080 و 2100، تحت 2 سناریوی a1b و a2، که در گزارش چهارم ipcc آمده، مقایسه شده است. طبقه‌بندی‌های حاصل از خروجی مدل روند رو به رشد اقلیم گروه b که نماینده اقلیم خشک و نیمه‌خشک در طبقه‌بندی کوپن است و کاهش تنوع اقلیمی را نشان می‌دهند. همان‌طور که در نقشه‌ها ملاحظه می‌شود و بر اساس وسعت تحت پوشش ‌این نوع اقلیم طی سال‌های آتی، افزایش اقلیم bwh که آب‌وهوای گرم و خشک را نشان می‌دهد، به‌وضوح قابل مشاهده است. ‌این افزایش به‌گونه‌ای است که در سال 2100، شاهد پوشش بیش از 95 درصد مساحت کشور توسط ‌این اقلیم بر اساس هر دو سناریو هستیم. همچنین وسعت و تنوع مناطق تحت پوشش اقلیم معتدل (اقلیم گروه c) و اقلیم سرد (اقلیم گروه d ) در کشور به کمتر از یک درصد مساحت کشور خواهد رسید.

An investigation on Copen’s Climate Classification in 1975 in Comparison with the Output of MIROC in the years 2030, 2050, 2080, and 2100 under Scenario A1B and A2

. IntroductionClimate, is the general condition of the prevailing weather conditions in a specific location based on its longterm statistics. The diversity of climatic elements affects determining the climate of a region and forms a variety of climates. Comparing the characters of the recorded weather in different places of the earth reveals significant differences in the surface of this planet. Thus, every place has unique characteristics. Comprehending the weather and ultimately climate has been an important consideration for human beings since a long time ago and has a significant importance in today’s human life. Comprehending the natural characteristics of each region, particularly, climate, plays a major role in land use planning. In order to achieve this objective, climatic zoning to identify different areas of climate seems to be necessary. From a geographer 's point of view, climatic zoning means organizing and categorizing the zones climatically in a way that each region has similar climatic characteristics. On the other hand, the increase in emissions of greenhouse gases and subsequently climate change and global warming have had many consequences for the planet. Particularly, the areas which are in the warm and dry belt, for the growth of the dry and semidry climate’s coverage is increasing. Climate change is a longterm and nonrecoverable climatic condition which occurs over a period of tens or millions of years in an area 's climate. The recorded data suggests that from 1901 to 2012, the temperature of the earth’s surface and the temperature of oceans have increased averagely 0.89 degrees Celsius. Therefore, changes in the climate of different parts of the world and the displacement of the existing boundaries of the climatic zones are expected. Due to the wide geographic latitudes and the existence of different local conditions in different regions, Iran has a wide climatic diversity and this issue has raised the importance of climatic zoning in this country. On the other hand, due to Iran’s presence in the warm and dry belt of the world, the country is affected by the global warming and climate change issues. Therefore, the study of new climate conditions in the country, as well as a survey on the possible movements of the existing boundaries of the climatic zones will be necessary.2. Material and Methods In this study, the information from Copen’s classified data for Iran, which are turned to maps, using the ArcGis software, using the year 1975 as a base year and the simulated data, using the atmosphereocean MIRCOH model for simulation, which is presented in the fourth report IPCC (AR4), under two scenarios A1B and A2, has been used for the years 2030, 2050, 2080 and 2100. Then, Copen’s climate classification for Iran in 1975, is compared to the classification of atmosphereocean MIROC output for the years 2030, 2050, 2080 and 2100 under the two scenarios A1B and A2. This model, with the cooperation of the National Institute for Environmental Studies (NIES), the OceanicPacific Institute of Oceanography (CCSR) Tokyo University and Japan Marine and LandBased Science and Technology Agency for predicting the 21st century climate, is designed with a relatively high degree of complexity and Resolution. Compared with HadCM3 models (With an atmospheric resolution of 3.75 ° 2.5 ° and oceanic 1.25 ° x 1.25 °), it has a higher resolution. Predictive atmospheric variables in this model include temperature, north and east wind components, and surface pressure, and predictive oceanic variables include the velocity of orbital and meridian wind, temperature, salinity, and altitude.3. Results and DiscussionIran’s climate in 1975 contains three primary groups, namely, B (dry and semidry with a lack of precipitation), C (temperate with mild winters) and D (cold, cold winter, the coldest month temperature is lower than 3 ° C) and subcategories of the three groups. As can be seen in Figure 2, climate group B is covering most of the country’s area. Bwh (T≥18˚c) climate, which represents the warm and dry climate, covers the widest area of the country (641043.7 km 2) and includes large parts of central Iran, South, South East, and South West of the country, which is about 40% of the country’s area. Moreover, regarding the Bsk climate, which is semidry and cold and indicates the extent of 22% in the North East, the eastern slopes of the Zagros and Alborz and Bwk climate, (cold and dry climate) 4.15 percent of the central country’s margin areas and parts of East and Southeast have been placed in next categories. In our country temperate climate from group C mostly appears in the Csa group form which represents the Mediterranean climate in our country, covering about 6 percent of the country’s area, including regions of North, Northwest, West and the western foothills of the Zagros. The cold climates Group D, appears in the mountainous regions of the West and North West of the country which covers 12% of the country’s area. Considering the climate change and global warming issues, which have been effected in the recent years, many models and methods have been used to rebuild and predict the global climate for the coming years. Although these models still have weaknesses and shortcomings to predict the future of the earth accurately, they also have much strength that makes them credible to predict and understand the future climate of the planet. The use of the output of atmosphereocean that coupled general circulation models are increasing as the most credible tool in climate change research. Various versions of the (AOGCM) models have been presented, including the 4th International Climate Change Board Assessment Report (AR4) (2007).The classifications based on the model’s output indicates a growing trend in group B, which represents the dry and semidry, in Copen’s classification. Considering the outspread area covered by this type of climate over the coming years, climate Bwh (hot and dry climate) is increasing, such an increase that in 2100, more than 95 percent of the country is covered by this type of climate based on both scenarios. While temperate climate group c, which represents the Mediterranean climate in Iran, just appears in parts of coastal North and North West of the country, group D includes very narrow cold climate areas of the mountainous areas of the North West. In general, the results from the model’s output, reveals a gradual increase in the size of the area covered by the warm and dry climate and a decrease of the cold and temperate climate in Iran over the coming years until 2100. Thus, we can see the adverse effects of climate change and global warming and the shifting borders of the Copen’ climate categories in the country.