بازسازي الگوي تغييرات برودتي و رطوبتي منطقه قروه در فاز اقل كواترنر

Reconstruction Pattern of the Cooling and Moisture Changes of Ghorveh region at Least Phase of the Quaternary

مساله شناخت قلمرو اقليمي و تغييرات آن دركواترنر براي ژيومورفولوژيست ها اهميت به‌سزايي دارد. زيرا اين تغييرات از عوامل اصلي شكل زايي كنوني زمين است؛ به‌طوري‌كه سبب تغييراتي در حوزه عملكرد سيستم هاي شكل زا، سطح كرايوسفر، ارتفاع مرز برف دايمي، زبانه‌هاي يخچالي، مرز رويش و نظام‌هاي هيدرولوژيكي شده است. امروزه طراحي برنامه هاي توسعه و پيشرفت، بهره‌برداري صحيح از منابع، حفظ محيط زيست، كاهش ميزان خسارات ناشي از مخاطرات طبيعي و بسياري از مسايل حياتي، بدون انجام اين مطالعات مشكلاتي در پي خواهد داشت. تغييرات اقليمي، به‌ويژه در فاز اقل(1) كواترنر، تاثير قابل توجهي بر رفتار رودخانه‌اي، حجم و ذخيره منابع آبي و كانون-هاي يخ‌ساز اين منطقه داشته است. از آنجايي كه پارامترهاي اقليمي دما و بارش به تغيير اقليم حساس مي‌باشند، بررسي روند زماني و شواهد يخچالي در چنين متغيرهايي يكي از شاخص‌ترين ابزارها در بازسازي الگوي تغييرات اقليمي و سيستم هاي مورفوژنتيك منطقه در فاز اقل كواترنر است. روش‌هاي مورد استفاده در اين تحقيق، ميداني، كمّي آماري و كتابخانه‌اي است. در تجزيه و تحليل اطلاعات از شاخص هاي فرميك روي نقشه‌هاي توپوگرافي 1:50000، مدل ارتفاعي رقومي Dem و نرم افزارهاي Global Mapper،Surfer استفاده شده است. در اين پژوهش، با استفاده از روش هاي ذكر شده آثار سيرك‌هاي يخچالي و خط برف دايمي در فاز اقل كواترنر به روش رايت تعيين شد. سپس نقشه‌هاي هم دما و هم بارش كنوني ترسيم و با ايجاد رابطه خطي، شرايط برودتي و رطوبتي منطقه در فاز اقل بازسازي شد. آنومالي هاي برودتي و رطوبتي منطقه در زمان حال و فاز اقل مشخص شد. با تحليل ميزان برف‌باري گذشته و زمان لازم براي حركت زبانه يخي ارتفاع خط تعادل آب و يخ و مرز برف دايمي در منطقه شناسايي شد. در نهايت، سيستم هاي مورفوژنتيك منطقه در فاز اقل و فعلي بازسازي شد.

Extended abstract 1-Introduction The problem of recognizing terrain climate and its changes is central to geomorphologist, because these changes are the main factors in the current creation of landforms; such that it introduced changes in the land form systems, cryosphere level, and altitude of the permanent snow line, glacier tongues, growth boundary and hydrological systems. Nowadays, designing development programs, proper utilization of resources, environmental protection, reducing the amount of damage caused by natural disasters and many crucial problems without careful consideration of these studies will create numerous problems. Climate changes in particular during the least phase of the quaternary have a significant impact on the behavior of the river and the volume of stored water and ice focuses in this area,since the climatic parameters of temperature and precipitation are sensitive to climate change. Therefore, studding of the time trend in these variables and the evidence of glaciers is one of the most significant indicators in the reconstruction of climate changes and morphogenetic systems during the least phase of quaternary. 2-Theoretical bases The methods used in this study included a field, statistical-quantitative, library method. In analyzing the data, morphic indicators on 1:500000 topographic maps, digital elevation model and the Global Mapper and Surfer softwares were used. In this study, we used four sheets of topographic maps and layers of the evidence of the cirqus of glacier, water permanent snow line, Equilibrium line of the ice and water, and Equilibrium line of the land identified. Cyclical climatic data were collected and attempts were made to draw the thermal profile of the area, simultaneously. The Wright method was applied to analyze the past and present conditions and provided the necessary conditions for spatial analysis. 3-Discussion Qorveh plain in Kordestan Provience is located between 35° - 35° 15ʹN latitude and 47° 45ʹ-48° 5ʹ E longitudes. The Qorveh region is one of the areas affected by climatic fluctuations during glacial phases. These changes were identified and studied using the statistical analysis of meteorological stations, some geomorphic evidence, geomorphologic principles, and glaciers. In this study, evidence of the cirqus of glacier and permanent snow line at least phase of quaternary was collected through the use of the mentioned methods, and in accordance with to Wright method’s. Therefore, isothermal and precipitation Maps were drawn and the moisture and cooling conditions were reconstructed by creating the linear relationship at least phase of quaternary. Cooling and moisture anomalies were identified at the present time and least phase. The altitude of the Equilibrium line of the ice and water and permanent snow line were identified by analyzing the amount of snow precipitation in the past And the time required to move ice tongue in the region. Finally, morphogenetic systems of the area were reconstructed and analyzed at least and present phase 4-Conclusion The results showed that the highest correlation correlated with a linear relationship and temperature drop estimated with increasing every 100 meters of altitude. Regarding the cooling and moisture anomalies in the region at present and at least phase, it was found that the temperature in least Quaternary in comparison with the present temperature differed about 5.9 ° C. Therefore, the difference in the annual mean temperature in the region was 6.2 ° C. Regarding the height of temperature of zero degrees in the past and the present condition, the permanent snow line has retreated at approximately 1000 m compared with the least quaternary phase. Also, isothermal and precipitation Maps at present and past identified that in general, the volume of rainfall at quaternary time was twice that of the present phase. Regarding the cited evidence, the altitude of permanent snow line is above 2700 m in the area and of water and ice equilibrium line is 1900m.identification and reconstruction of the morphogenetic systems in present condition and least phase demonstrated that The loss of glaciers in mountainous and the equilibrium line changes since quaternary results to displacement of the morphogenetic boundaries, ecosystems and humans.