Meteorological driving factors effecting the surface area of Ebinur Lake and determining associated trends and shifts

Abstract

Changes in lake water resources and regional hydrological processes in response to climate change and human activity necessitates timely and accurate access to lake change information to monitor water cycles and water security. The Ebinur Lake Basin has experienced a serious ecological crisis in recent years, which is majorly due to excess use of its water. Therefore, in this study, we used Ebinur Lake as a research object, and used Geographic Information System and remote sensing technology, Landsat, Sentinel, and MODIS images, the Google Earth Engine platform, and the water body index method to determine the changes in lake area from April to October of 2011–2020. Daily data from the Alashankou and Jinghe meteorological stations from 2011 to 2020 were collected. The center of gravity-geographically and temporally weighted regression model was used to analyze the factors changes in surface area. The results showed obvious spatial and temporal heterogeneities for the surface area. Except for 2016, which had unusual/extreme weather, in the last decade, the lake surface area generally showed a monthly decreasing trend from April to October. When Ebinur Lake is one water body, the surface area ranges between 530 and 560 km2. We concluded that the spatio-temporal characteristics of Ebinur Lake can be divided into two levels. When the southeast and northwest regions of the lake merge, it represents the largest possible surface area of Ebinur Lake; this was called the “water storage level”. Historically, Ebinur Lake has lost significant amounts of water, and there is no water body connecting the two main parts of the lake (thereby dividing the lake into two areas); this was called “water demand level”. The trajectory of the center of gravity of the lake is linear, with a slope of 45° and a direction of northwest to southeast. The lake gravity center has different aggregation states. According to the season, it can be divided into spring gathering and autumn gathering. The variation in the surface area of Ebinur Lake is highly correlated with the meteorological and hydrological variation during the year. The highest correlation was observed between lake surface area and wind speed. This study aimed to supplement other studies that explore the lake annually and provide a reference for future water resources management and planning.

Spatial and Temporal Variation in Vegetation Response to Runoff in the Ebinur Lake Basin

“…The annual evaporation rate exceeds 1000 mm. The terrain of the watershed is complex, flanked by mountains on three sides, and is a well-known wind outlet in China, with northwest winds dominating in all years [28]. The watershed vegetation is classified into seven types: alpine vegetation, coniferous forests, agricultural fields, grasslands, meadows, shrubs, and deserts.…”

“…In this context, many researchers have studied the internal causes of lake area changes, runoff (channel flow) changes, land-use changes, and soil salinization to address increasingly prominent water resource problems [27][28][29]. Water scarcity in the Ebinur Lake Basin has been linked to a decrease in runoff caused by climate change and an increase in water demand caused by increasing the expansion of cultivated land and plantation [28,30]. Different types of land use have different impacts on vegetation and runoff [19,27,30].…”