Influences of climate change on area variation of Qinghai Lake on Qinghai-Tibetan Plateau since 1980s

Abstract

Qinghai-Tibetan Plateau is the most sensitive region to global warming on Earth. Qinghai Lake, the largest lake on the plateau, has experienced evident area variation during the past several decades. To quantify the area changes of Qinghai Lake, a satellite-based survey based on Landsat images from the 1980s to 2010s has been performed. In addition, meteorological data from all the seven available stations on Qinghai-Tibetan Plateau has been analyzed. Area of Qinghai Lake shrank ~2% during 1987-2005, and then increased ~3% from 2005-2016. Meanwhile, the average annual temperature increased 0.319 °C/10 y in the past 50 years, where the value is 0.415 °C/10 y from 2005-2016. The structural equation modeling (SEM) shows that precipitation is the primary factor influencing the area of Qinghai Lake. Moreover, temperature might be tightly correlated with precipitation, snow line, and evaporation, thereby indirectly causes alternations of the lake area. This study elucidated the significant area variation of water body on the Qinghai-Tibetan Plateau under global warming since 1980s.

Figure 1

The distributions of all the seven meteorological stations (Dachaidan, Dulan, Gangcha, Golmud, Xining, Yushu, and Lhasa). Gangshika peak is marked as triangle. The image was generated by ArcGIS software (Version 10.2 for Desktop).

Figure 2

Annual precipitation of Dachaidan, Dulan, Gangcha, Golmud, Xining, Yushu and Lhasa from 1970–2016. The black solid line is the trend line of average values of annual precipitation for the seven locations.

Figure 3

Area of Qinghai Lake in July and August and average altitude of snow line in Gangshika peak ranged from 1987–2016.

Figure 4

Annual pan evaporation of Dachaidan, Dulan, Gangcha, Golmud, Xining, Yushu and Lhasa from 1970–2003 measured by small evaporator. The black solid line is the trend line of the average values of annual pan evaporation collected from the seven locations.

Figure 5

Average daily pan evaporation of Dachaidan, Dulan, Gangcha, Golmud, Xining, Yushu, and Lhasa from June to August within 2004–2016 (no available data of Yushu in 2006–2007 and 2015–2016). The evaporation was measured by evaporation tank. The black solid line is the trend line of the average values of average daily pan evaporation collected from the seven locations.

Figure 6

Annual mean temperature of Dachaidan, Dulan, Gangcha, Golmud, Xining, Yushu and Lhasa from 1970–2016. The black solid line is the trend line of average values of annual mean temperature collected from the seven locations.

Figure 7

A model of relationships between Qinghai Lake area, temperature, precipitation, evaporation and snow line. Data of Gangcha station that nearest to Qinghai Lake is selected (Thickness of the line indicates the strength of the correlation, and the number represents the correlation coefficient. The dotted line indicates that the correlation is not significant).