Estimation of precipitation and runoff estimation accuracy using GLDAS model in Qazvin province

Today, considering the reduction of water resources and the existing water crisis, attention to integrated water resources management is essential. One of the basic measures in this field is to know the amount of rainfall, runoff and changes in the catchment area. The purpose of this study was to evaluate the accuracy of estimation of precipitation and runoff in Qazvin province using the GLDAS model and the measured data at nine synoptic and barometric stations and eight hydrometric stations. For this purpose, global ground-level data (GLDAS) was used with a spatial resolution of 0.25 × 0.25 on a monthly basis from 2001 to 2010 for synoptic and parachute stations and from 2002 to 2008 for a hydrometric station. Researches have shown that there is a good correlation between rainfall and runoff data with GLDAS model. The results of statistical assessments for rainfall data were R2 =0.93, MBE =13.57, MAE =13.57 and RMSE =15.95 mm per month for Qazvin Station in 2002 and in relation to runoff data, R2 = 0.92, MBE =-0.82, MAE = 0.82 and RMSE = 1.53 mm for the Haji-Arab station in 2007. According to the results, the use of runoff and precipitation data of the GLDAS model in the studied basin is suggested in areas where access to them is difficult.