Figure 5

3.4 The main attribution of TWS changes in the EIB

Figure 6 shows the spatial distribution of the TWSA trends in the EIB for 2002–2020; generally, this distribution was similar among the five products, in which significant decreasing trends were observed in most regions. The highest decreasing magnitude was observed in the Caspian Sea region. The TWSA showed that there were significant increasing trends in several regions, including headwater regions (mainly located in the Qinghai-Tibetan Plateau) of the QB, QPB, and TaRB in the southeastern EIB and a small part of the north-central EIB (headwaters of the northwest BLB). In addition, the TWSA also showed non-significant increasing trends in some headwater regions of the Volga River. Although the spatial distribution of trends was consistent among the five products, there were clear differences in the magnitude of the trends for the Caspian Sea region, especially at the core part of the Caspian Sea. The decreasing magnitude of two mascon products exceeded -70 cm/10a at the core part of the Caspian Sea, which is more than twice that of the v3 products.