Temporal and Spatial Variations of Soil Moisture Over Xinjiang Based on Multiple GLDAS Datasets

Abstract

Under the global warming, as the typical arid region of Central Asia, the Xinjiang Uygur Autonomous Region (Xinjiang) has been experienced the remarkable warming and increased precipitation based on large previous studies. The arid and semiarid ecosystem of Xinjiang is very sensitive and vulnerable to climate change and water resource variations. However, the sparse and highly unevenly distributed in-situ stations in this region provide limited data for understanding of the soil moisture variations. In this study, the spatial and temporal changes and variations of soil moisture were explored at annual and seasonal time scales during the period of 2000–2017. The soil moisture data are from the Global Land Data Assimilation System (GLDAS) models, including four GLDAS 1 models: CLM, Mosaic, VIC and Noah 2.7 and one GLDAS 2.1 model: Noah 3.3. Major results show that 1) Noah 3.3 and VIC have the significant positive trends of annual soil moisture with the values of 2.64°mm/a and 0.98°mm/a. The trend of CLM is significant negative. The other two models Mosaic and Noah 2.7 have the weak positive trends. The temporal variations of seasonal soil moisutre are similar the annual soil moisture for each of the model. 2) For the spatial characteristics of the soil mositure variations, CLM displays the negative trends over large part of Xinjiang. Mosaic and VIC have the similar spatial characteristics of the linear trends. Noah 3.3 has the significant positive trends over almost Xinjiang which is different with Noah 2.7. All the five models have the positive trends over KLM. Our results have a better understanding of the soil moisture variations across Xinjiang, and they also enhance the reconginzing of the complex hydrological circulation in the arid regions.

Spatiotemporal features of the soil moisture across Northwest China using remote sensing data, reanalysis data, and global hydrological model

“…Climate change, terrestrial water storage variations, and the response of soil moisture to climate and plants have substantial regional disparities. A previous study detected an increased soil moisture trend in Xinjiang during 2000-2017 using six GLDAS models (Hu et al, 2021a). Nevertheless, remote sensing and reanalysis data were not considered.…”

Characteristics and physical mechanisms of a rainstorm in Hotan, Xinjiang, China

“…Its complex topography includes three mountain ranges: the Altain Mountains in the north, Tianshan Mountains in the middle, and Kunlun Mountains in the south. Two basins are situated between the mountain ranges which are, from north to south, the Junggar Basin and Tarim Basin (Figure 1, Hu et al, 2021b).…”

“…In these regions, moisture fluxes are mainly sourced from the Atlantic and Arctic Oceans (Schiemann et al, 2008;Chen et al, 2018). Evaporation is much higher than precipitation, causing vulnerability in ecosystems and lake water resources, which is exacerbated by changes in temperature and precipitation (Hu et al, 2021b;Hu et al, 2022a).…”

“…In recent decades, the temperature has shown a significant positive trend, and precipitation has increased overall (Hu et al, 2014;2016a, 2017. Variations in precipitation in Central Asia have been proven to significantly impact terrestrial water resources (Hu et al, 2021a;2021b;2022a;Zhou et al, 2022) and the spatiotemporal patterns in vegetation coverage and biomass (Yin et al, 2016;Zhang et al, 2016). However, owing to global warming, extreme climate events, including extreme precipitation, are increasing (Tank et al, 2006;Gessner et al, 2014;Hu et al, 2016b).…”

“…It is located inland and far from any oceans, has complex mountains and basins, is adjacent to the Qinghai-Tibet Plateau, and receives minimal precipitation. Southern Xinjiang is particularly dry all year because the potential evaporation is much higher than precipitation (Hu et al, 2021b). Owing to global warming, extreme weather events, including severe droughts and heavy precipitation, have become more frequent and intense during the past decade, and extreme precipitation has begun to occur in arid areas (Zhang et al, 2012;Wang et al, 2013).…”