آشکارسازی تغییر نوسانات فصلی متغیرهای اقلیمی و نسبت دهی به تغییر اقلیم (محدوده مطالعاتی: دامنه های جنوبی البرز مرکزی)

یکی از چالش های اصلی پیش روی بشر، بحث گرمایش جهانی و اثرات تغییر اقلیم می باشد. در این تحقیق سعی شده تا با بررسی روند متغیرهای اقلیمی مشاهداتی مختلف شامل بارش، دمای حداکثر و دمای حداقل طی فصول مختلف در محدوده دامنه های جنوبی البرز مرکزی (استان تهران و البرز) علاوه بر اثبات تغییر اقلیم ناشی از گرمایش جهانی، میزان دخالت هر یک از واداشت های عمده از جمله گازهای گلخانه ای تعیین گردد. در این راستا با استفاده از روش درون یابی وزن دهی معکوس فاصله (idw)، داده های مشاهداتی سه ایستگاه همدیدی آبعلی، مهرآباد و کرج به صورت پهنه ای تبدیل شد و با میانگین گیری غیرمتداخل سه ساله و محاسبه آنومالی متغیرهای مشاهداتی و شبیه سازی عوامل مرکب (all)، عوامل طبیعی (nat)، گازهای گلخانه ای (ghg) و اجراهای کنترل پیش از انقلاب صنعتی ارکان مورد نیاز آشکارسازی و نسبت دهی فراهم شد. با کاهش حجم داده های حاصل از اجراهای کنترلی به وسیله توابع غیرمتعامد تجربی (eof) و استفاده از روش انگشت نگاشت بهینه و آزمون ثبات باقیمانده ها، تاثیر هر یک از سیگنال ها مذکور بررسی شد. با توجه به نتایج حاصل شده، برای آنومالی هر سه متغیر بارش، دمای حداکثر و دمای حداقل به ترتیب طی فصول زمستان، تابستان و بهار سیگنال all، آشکارسازی و نسبت دهی گردید. به علاوه برای دمای حداقل بهاره سیگنال ghg در تغییرات دما نقش موثری دارد. بدین ترتیب بالاترین ضرایب مقیاس ساز ( beta;) تحت واداشت های مرکب all به ترتیب مربوط به میانگین غیرمتداخل سه ساله بارش های زمستانه (0.88)، میانگین دمای حداقل بهاره (0.78) و میانگین دمای حداکثر تابستانه (0.76) می باشد. و ضریب مقیاس ساز گازهای گلخانه ای که فقط برای میانگین دمای حداقل بهاره آشکارسازی و نسبت دهی گردید (0.73) می باشد.

Detection and Attribution of Changing in Seasonal variability cause of climate change (Case study: Hillsides of Central Southern Alborz Mountains)

Detection and Attribution of Changing in Seasonal variability cause of climate change (Case study: Hillsides of Central Southern Alborz Mountains)AbstractOne of the most important challenges for the human communities is Global Warming. This vital problem affected by Climate Change and corresponding effects. Thus this article attempted to assess the trend of real climate variables from synoptic stations. Daily precipitation, Daily Maximum Temperature and Daily Minimum Temperature have been selected for the Hillsides of Southern Central Alborz Mountains and have been tried to prove climate change and attribute the related forcing such as Greenhouse Gases. The Capital of Iran located in this region and this region has a special occasion, because at least a quarter of Iranian population live in these provinces (Tehran and Alborz) and four big dams located in this region. The Intergovernmental Panel on Climate Change rsquo;s defines lsquo; lsquo;detection rsquo; rsquo; of climate change as lsquo; lsquo;the process of demonstrating that climate or a system affected by climate has changed in some defined statistical sense, without providing a reason for that change, rsquo; rsquo; while lsquo; lsquo;attribution rsquo; rsquo; is defined as the process of evaluating the relative contribution of multiple causal factors to a change or event with an assignment of statistical confidence. Regional D A studies provide an insight to local changes in natural systems and may help in planning and developing robust adaptation strategies. Previously, formal detection and attribution have been used to investigate the nature of changes in various climatological variables such as air temperature, surface specific humidity, ocean heat, sea level pressure, continental river runoff, global land precipitation and precipitation extremes. However, almost all of these studies deal with climatological or meteorological variables at the global or continental scale. Studies which have attempted to formally detect and attribute regional hydrometeorological changes to anthropogenic effects are rare. Regionalscale D A analysis is more difficult because the detection of anthropogenic lsquo; lsquo;signal rsquo; rsquo; in natural internal climate variability lsquo; lsquo;noise rsquo; rsquo; is determined by the signaltonoise ratio which is proportional to the spatial scale of analysis, especially for real observation data. For overcoming this issue interpolation method (IDW) has been applied to transfer point data to area (gridded) data. The point data gathered from 3 synoptic stations (Mehrabad, Karaj and Abali). Then transferred data have been Standard and Averaged for 3 years. Standard values of annual and seasonal amounts have been computed for individual stations as the average of the standard values of annual and seasonal amounts available 3 years anomaly values. Estimates of annual or seasonal variables anomalies were obtained by averaging the annual or seasonal by 12 or 3 respectively. For detecting and attributing 3 simulation signals (ALL, GHG and NAT) selected from Canadian General Circulation Model (CanESM2.0) of CMIP5 archive subcategories. Space -time series of observations and model simulated variables responses to external forcings (the ldquo;signals rdquo;) first have been compared qualitatively by computing correlation coefficients between observations and simulations. This simple method does not optimize the signaltonoise ratio nor provide a quantitative measure of the magnitude of model simulated response relative to that in the observations. Nevertheless, it provides an easytounderstand view of the similarity between observed and modelsimulated changes. Optimal detection and attribution analysis very often requires a reduction of dimensionality. This is typically done by projecting both observations and simulations onto leading empirical orthogonal functions (EOFs) of internal variability and using the residual consistency check to determine the number of EOFs to be retained in the analysis. To produce internal variability for residual test and consistency, PiCtrl Runs have been used. The Preindustrial simulations have high volume, this subject complicates calculation therefore Experimental Orthogonal Functions (EOFs) have been used to reduce the PiCtrl simulations volume and provide situations for Optimal Fingerprint. Optimal Fingerprint method is the best method for Detection and Attribution. Results have been obtained by this manner indicated Global Warming affected the study region by affecting on mean cumulative winter precipitation (0.88), mean spring minimum temperature (0.78) and mean summer maximum temperature (0.76). These numbers are the beta coefficient that named scaling factor. Although the scaling factor for the mean spring minimum temperature affected from GHG signal obtained (0.73), but the GHG forcing alone didn rsquo;t have a significant effect on the precipitation and maximum temperature. Also, NAT signal didn rsquo;t have significant effect on the region alone, too. The obtained results of this study indicate the earlier studies, such as Wan et al, 2014. Key words: Climate change, Detection, Attribution, Optimal Fingerprint, Hillsides of Central Southern Alborz Mountains