1دانشجوی دکتری هیدروژئولوژی، گروه زمین‌شناسی، دانشکدۀ علوم زمین، دانشگاه شهیدبهشتی، تهران- ایران
2دانشیار گروه زمین‌شناسی، دانشکدۀ علوم زمین، دانشگاه شهیدبهشتی، تهران- ایران
3دانشیار گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران، پاکدشت- ایران
چکیده
در این مطالعه، اثرهای تغییر اقلیم بر آبخوان آبرفتی دشت همدان-بهار، واقع در غرب ایران بررسی شده است. مدل‌های مختلف اقلیمی بر مبنای توانایی آنها در شبیه‌سازی متغیرهای اقلیمی در دورۀ پایه (2000-1970) وزن‌دهی شده‌اند. سپس بر مبنای وزن مدل‌های اقلیمی و مقادیر پیش‌بینی‌شده توسط آنها در دورۀ آتی (2045-2015)، تغییرات بارندگی و دما در سطوح احتمال مختلف 10، 50 و 90درصد محاسبه می‌شود. در این بررسی، از داده‌های اقلیمی ایستگاه سینوپتیک همدان و مقدار تغییرات بارش و دما در سطح احتمال 90درصد برای سناریوی انتشار A2، به‌عنوان بحرانی‌ترین شرایط از نظر تغذیۀ آب زیرزمینی استفاده شد. مقادیر بارش و دما نیز به‌وسیلۀ مدل لارز- دبلیوجی، به شکل روزانه برای دورۀ آتی تولید گردید. با استفاده از شبکۀ عصبی چندلایه و مدل آب زیرزمینی مادفلو، به‌ترتیب مقادیر رواناب روزانه و نوسانات سطح تراز آب زیرزمینی تخمین زده شد. نتایج نشان‌دهندۀ افت سطح آب زیرزمینی به میزان 38 متر در دورۀ آتی، به‌خصوص در مناطق جنوب و جنوب‌غربیِ آبخوان، ناشی از برداشت چشمگیر آب زیرزمینی است. با توجه به ضخامت اشباع کنونی آبخوان که حدود 50 متر است، در پایان دورۀ مدل‌سازی، ضخامت اشباع آبخوان حدود 12 متر خواهد بود.
1Ph.D. Student, Earth Science Faculty, Department of Geology, University of Shahid Beheshti (SBU), Tehran, Iran
2Associate Professor, Earth Science Faculty, Department of Geology, Shahid Beheshti University (SBU), Tehran, Iran
3Associate Professor, Department of Irrigation and Drainage Engineering, Abourayhan Campus, University of Tehran, Pakdasht, Iran
چکیده [English]
This study will evaluates climate change impacts on groundwater resources in Hamadan-Bahar alluvial aquifer in the west of Iran. Different climate models are weighted in the basis of their ability in predicting monthly observed climate data in the base study period (1970-2000). With respect to climate models weights and their predictions, precipitation and temperature changes in 10, 50 and 90 probability percentile are estimated. Daily observation data of Hamadan synoptic station and ΔP, Δt under A2 emission scenario at 90 probability percentile, as a critical condition in groundwater recharge, have been imported to an stochastic weather generator, named LARS-WG, and future precipitation and temperature data are produced for the study period (2015– 2045). Multi layer perceptron artificial neural network and visual MODFLOW are used for simulating daily run off and groundwater table respectively. Simulated groundwater table indicates a significant depletion in groundwater table around 38 meters specially in the south-southwest of aquifer and at the end of modeling period aquifer saturated thickness will be less than 12 meters.
کلیدواژه‌ها [English]
climate models, Groundwater, MODFLOW model, probability level, Runoff
مراجع
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