Detection and trend analysis of drought in the Jazmurian basin of Iran associated with ocean- atmospheric indices

Evaluation the drought hazard in the basins of Iran located in the arid and semi- arid belt of the world is important from various dimension. While the role of teleconnection patterns in studying climatic hazards has been given more attention by researchers in recent decades. In this regard, the purpose of this research is to investigate and analyze the drought of the Jazmurian basin, a representative of one of the sub-basins of the central catchment located in the arid and semi-arid region of Iran. The humidity anomalies were investigated using the available Satellite and recorded data. This research revealed the humidity anomalies of the Jazmurian basin by using NDWI and MNDWI indices and also investigate the efficiency of using moisture composite spectral indices. Spectral analysis of humidity index in three time periods of 1985-2000, 2000-2013, and 2013-2020 in the Jazmurian basin showed that both MNDWI and NDWI indices in the three time periods studied to detect the existence of drought and negative humidity anomalies in the basin. Also, the results showed that the interpretation and analysis of spectral composite indices could not prepare the details of drought characteristics in this basin. Investigating the relationship between the SPEI drought index and ocean-atmospheric fluctuations was done using a multiple regression model. The results showed that the drought of the Jazmurian basin has a stronger significant relationship with the AMO and SOI indices at the 95% significance level and based on the results of the multiple regression model, the AMO explained more than 70% of the drought anomaly in Jamurian basin. The synoptic analysis of the drought showed that the stable conditions and atmospheric circulation during the warm phase of the AMO caused subsidence and stable weather conditions and increased the severity of the drought in the Jazmurian basin in the 1999.