جستجوی مقالات مرتبط با کلیدواژه « شاخص های خشکسالی » در نشریات گروه « مهندسی آب »

Drought can mainly affect agriculture, especially rainfed agriculture due to its high dependence on precipitation, thereby compromising food security and social protection. In this study, the correlation between SPI and SPEI drought indices with rainfed wheat yield of 5 filds in Saqqez city during the period of 2001-2020 was investigated with neural network, random forest and support vector regression. TRMM precipitation and CRU evapotranspiration were used to calculate SPI and SPEI drought indices. The AquaCrop model was calibrated with observational data and then filds performance was simulated with the AquaCrop model for the period 2001-2020. The average yield of the filds was evaluated with the average yield of the entire Saqqez city, and the results showed that the data simulated with the model had a good correlation (R2=0.90) with the average rainfed wheat yield of Saqqez city. The results of evaluating the relationship between SPI and SPEI indices with rainfed wheat yield showed that the neural network and random forest method with a significant probability of 95% (P-value=0.0) and an explanatory coefficient of more than 0.70% and a high value of Nash Sutcliffe index And a small amount of underestimation has had a good estimate of the rainfed wheat yield and there is a significant relationship between SPI and SPEI drought indices with the rainfed wheat yield in the study area.

Drought is one of the most important climatic phenomena that is caused by climatic anomalies. Which occurs periodically due to lack of moisture due to reduced rainfall. Drought duration may vary from month to several years. Therefore, by monitoring and evaluating the drought, the damage caused by it can be reduced. Drought is one of the most important and destructive phenomena that in recent years has left many economic and social effects in the city of Islamabad, West. Therefore, in this study, the drought situation of Islamabad West using rainfall data in 30 years (1991 to 2020) using DIP software on an annual basis of drought status based on PNI, SPI, ZSI, CZI was used as a measure to monitor meteorological drought. The results showed that these indicators were consistent with each other, so that based on the above indicators, the results show that in Islamabad West in 1999 and 2014, the most severe drought occurred in the statistical period. In 2005 and 2008, drought occurred with a moderate drought situation.

In this study, drought monitoring based on three drought indexes SPI, RDI and SPEI in stations Babolsar, Bandar Abbas, Sabzevar, Shiraz and Zahedan in order to evaluate the impact ofthe evapotranspiration on drought has been paid. Correlation between 12-month scale drought indexes and 12-month moving average for some of the meteorological parameters was calculated. According to the results SPI index showed the highest correlation with rainfall. Also significant correlation between SPEI index and ETo were observed in different climatic areas. ETo correlation in low rainfall and dry areas with SPEI index shows extremely high values and with decrease in precipitation to ETo, the correlation value between SPEI index and ETo were increased. Affecting parameters onETo correlation with drought indices is lower than the correlation ETo with drought indexes and The amount of correlation this parameters with drought indexes, is directly affected by its correlation with ETo. These parameters are implicitly affect the drought and its effects on aggregate drought is more effective. Due to high correlation of parameters ETo with drought conditions in most regions studied is suggested that in arid and semi-arid area SPEI index (compared with indices SPI and RDI) should be used for drought monitoring. On the other hand; the use of SPI index in these areas is not recommended in any way. However, in areas with precipitation to ETo ratio close to one, using based on rainfall indices such as SPI can be well region's status.