Figure 2
Precipitation trends in the EIB and 16 closed inland basins were detected based on the GPM satellite data. Figure 3 shows the trends in annual and monthly precipitation for each basin for 2002–2020. There was a slightly increasing trend in annual precipitation in the EIB, with the magnitude of 3.7 mm/10a. The decreasing trend was detected in the BLB, CSB, IIRB, JB, QPB and TuRB; these basins are mainly distributed in the western and northern EIB. The annual precipitation was increasing in the remaining ten basins, in which the HRB had the largest increase of 52.3 mm/10a. The magnitude of the increase in the HRB accounted for 28.6% of the mean annual precipitation in this basin. The ratio of increases to the mean annual precipitation was also relatively higher at the TB (9.9%), IMPB (7.3%), and GHCB (6.9%). The magnitude of the decrease in the IIRB also accounted for -10.8% of the mean annual precipitation in this basin. The ratio of increases or decreases to the mean annual precipitation was within ±5% in the remaining closed basins. The annual precipitation trends were non-significant in the EIB and each closed basin. The increasing trend in the HRB was the closest to being significant (at p < 0.05). However, annual precipitation showed significant decreasing trends in three sub-basins (not shown), including the Issyk-Kul Lake, Southwest Caspian Sea, and Ural River basins; the magnitudes of these decreasing trends were -86.7, -68.8, and -57.3 mm/10a, respectively.