Climatic implications on variations of Qehan Lake in the arid regions of Inner Mongolia during the recent five decades

Abstract

The Qehan Lake Basin (QLB) and its system of lakes are located in a marginal monsoon zone and are extremely sensitive to global climate change. In this paper, using aerial photographs from different periods, in addition to MSS, TM, and ETM images, and combining these with regional topographic maps, we analyze lake area changes from 1958 to 2010 and the relation between Qehan Lake (QL) and climate variability. Our results indicate that there was a relatively high lake level in 1959, when the area and volume of the lake were 118.9 km² and 151.9 × 10⁶ m³, respectively, but this level was subject to a shrinking trend until 2010, when the lake area was only 28.1 km², and the water volume was 41.1 × 10⁶ m³. West Qehan Lake (WQL) has experienced severe water shrinkage and lake level fluctuation. In 1958, WQL was 80.2 km² in area and 124.1 × 10⁶ m³ in volume. However, due to a rapid decrease in precipitation and increases in both temperature and evaporation, it began to dry up in 2002. The WQL Water area decreased by 1.82 km²/a, and the lake level declined by 7 m during 1958-2002, so it became an ephemeral lake.

Keywords: Climatic change; Inner Mongolia; Lake level fluctuation; Semi-arid environment; Wetlands.

Fig. 1.

a Map of North China. b Qehan Lake (QL) catchment and location of four meteorological stations. c Qehan Lake area

Fig. 2.

a Changes in the Qehan Lake (QL) area for different periods. b DEM diagram of lake depth

Fig. 3.

Sequential Mann–Kendall test for a annual temperature and b annual precipitation of each site

Fig. 4.

Site temperatures (black line) and precipitation values (blue line) versus trends in WQL and QL area (black line) and volume (blue line), 1958–2010

Fig. 5.

Relation between reductions in West Qehan Lake (WQL) water volumes. a Mean annual temperature. b Mean annual precipitation. c Mean annual evaporation, 1958–2002