ارزيابي اثر تغيير اقليم بر خشكسالي كشاورزي به كمك شاخص SMDI با استفاده از مدل ها و سناريوهاي گزارش پنجم

The Evaluation of Climate Change Impact on Agricultural Drought by Soil Moisture Deficit Index Using Fifth Report Models and Scenarios

رﻃﻮﺑﺖ ﺧﺎك ﯾﮏ ﭘﺎراﻣﺘﺮ ﺗﻌﯿﯿﻦﮐﻨﻨﺪه در ﺑﺴﯿﺎري از ﻓﺮآﯾﻨﺪﻫﺎي ﭘﯿﭽﯿﺪه زﯾﺴﺖ ﻣﺤﯿﻄﯽ اﺳﺖ و ﻧﻘﺶ ﺗﻌﯿﯿﻦﮐﻨﻨﺪهاي در وﻗﻮع ﺧﺸﮑﺴﺎﻟﯽ ﮐﺸﺎورزي دارد. ﻟﺬا در اﯾﻦ ﺗﺤﻘﯿﻖ، ﺑﺎ اﺳﺘﻔﺎده از دادهﻫﺎي ﺑﺮآورد ﺷﺪه رﻃﻮﺑﺖ ﺧﺎك ﺗﻮﺳﻂ ﻣﺪل SWAP و دادهﻫﺎي ﮔﺰارش ﭘﻨﺠﻢ ﺗﻐﯿﯿﺮ اﻗﻠﯿﻢ، ﺧﺸﮑﺴﺎﻟﯽ ﮐﺸﺎورزي ﺑﻪﮐﻤﮏ ﺷﺎﺧﺺ ﮐﻤﺒﻮد رﻃﻮﺑﺖ ﺧﺎك ﺑﺮاي دوره آﺗﯽ )2039-2020( ﺑﺮاي ﻣﺰرﻋﻪ ﮔﻨﺪم ﻓﺎروب ﻧﯿﺸﺎﺑﻮر ﺗﻌﯿﯿﻦ ﺷﺪ. دادهﻫﺎي اﻗﻠﯿﻤﯽ ﺑﻪﮐﻤﮏ ﺷﺶ ﻣﺪل GCM و دو ﺳﻨﺎرﯾﻮ اﻧﺘﺸﺎر 4/5 و 8/5 ﺑﺮآورد و ﺗﻮﺳﻂ ﻣﺪل LARS-WG رﯾﺰﻣﻘﯿﺎس ﺷﺪﻧﺪ. ﺳﭙﺲ دادهﻫﺎي اﻗﻠﯿﻤﯽ رﯾﺰﻣﻘﯿﺎس ﺷﺪه ﺑﻪﻫﻤﺮاه دادهﻫﺎي زراﻋﯽ، ﺧﺎك و آﺑﯿﺎري وارد ﻣﺪل SWAP ﮔﺮدﯾﺪ. در ﻧﻬﺎﯾﺖ ﺑﺎ اﺳﺘﻔﺎده از دادهﻫﺎي رﻃﻮﺑﺖ ﻋﻤﻖ ﺻﻔﺮ ﺗﺎ 30 ﺳﺎﻧﺘﯽﻣﺘﺮي ﺧﺎك، ﺧﺸﮑﺴﺎﻟﯽ ﮐﺸﺎورزي ﺑﻪﮐﻤﮏ ﺷﺎﺧﺺ SMDI ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد، دﻣﺎي ﻣﯿﻨﯿﻤﻢ، ﻣﺎﮐﺰﯾﻤﻢ و ﺑﺎرش در دوره آﺗﯽ ﻧﺴﺒﺖ ﺑﻪ دوره ﭘﺎﯾﻪ اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ اﺳﺖ و ﺳﻨﺎرﯾﻮ 8/5 ﻧﺴﺒﺖ ﺑﻪ ﺳﻨﺎرﯾﻮ 4/5 دﻣﺎي ﺑﯿﺸﺘﺮ و ﺑﺎرش ﮐﻤﺘﺮي را ﺑﺮآورد ﮐﺮده اﺳﺖ. ﻫﻤﭽﻨﯿﻦ ﻣﯿﺎﻧﮕﯿﻦ SMDI در دوره آﺗﯽ ﻧﺴﺒﺖ ﺑﻪ دوره ﭘﺎﯾﻪ ﺑﺮاي ﻫﺮ دو ﺳﻨﺎرﯾﻮ اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ اﺳﺖ. ﻧﺘﺎﯾﺞ ﻗﻄﻌﯿﺖ ﻣﺪلﻫﺎي GCM در ﺑﺮآورد ﺷﺎﺧﺺ SMDI ﻧﯿﺰ ﻧﺸﺎن داد. ﺗﺤﺖ ﺳﻨﺎرﯾﻮ 4/5 ﻣﺪلﻫﺎي IPSL و MIROC ﺑﯿﺸﺘﺮﯾﻦ ﻗﻄﻌﯿﺖ و ﻣﺪل Canesm2 ﮐﻤﺘﺮﯾﻦ ﻗﻄﻌﯿﺖ وﻟﯽ ﺗﺤﺖ ﺳﻨﺎرﯾﻮ 8/5 ﻣﺪل MIROC ﺑﯿﺸﺘﺮﯾﻦ ﻗﻄﻌﯿﺖ و ﻣﺪلﻫﺎي 3.6-Csiromk و GFDL ﮐﻤﺘﺮﯾﻦ ﻗﻄﻌﯿﺖ را دارﻧﺪ.

Soil moisture is a determinative parameter in many of the complex environmental processes and plays a decisive role in the occurrence of agricultural drought. So, in this study, based on estimated soil moisture data by SWAP model and Fifth Report Data of Climate Change, agricultural drought was determined by Soil Moisture Deficit Index for the upcoming period (2020-2039) for the wheat field of Faroub in Neyshabour. The climatic data were estimated using six models of GCM and two emission scenarios of 4.5 and 8.5 and were downscaled by LARS-WG model. Then the downscaled climatic data along with field, irrigation and soil data were entered into the SWAP model. Finally, using soil moisture data of 0-30 cm depth, agricultural drought was evaluated using SMDI index. The results showed that the minimum and maximum temperatures and precipitation in the upcoming period have increased compared to the base period and 8.5 scenario have estimated a higher temperature and lower rainfall than the 4.5 scenario. Also, the average SMDI in the upcoming period has increased relative to the base period for both scenarios. The certainty results of GCM models for estimation of SMDI index also showed that under the 4.5 scenario, the IPSL and MIROC models have the highest certainty and the Canesm2 model has the lowest certainty. Under the 8.5 scenario, MIROC model has the highest certainty and Ciromk-3.6 and GFDL models have the lowest certainty.