Abstract
Changes in the water level of Qinghai Lake, the largest inland lake in China, directly affect the ecological security of Qinghai province and even the northwest of China. This study aimed to investigate the lake level and identify causes of changes in the lake level of Qinghai Lake. The results showed that the lake level was 3196.55 m in 1959 and gradually declined to 3192.86 m in 2004, with an average decreasing rate of 8.2 cm·year−1 over 45 years. However, the lake level increased continuously by 1.04 m from 2005 to 2010. During the period 1961–2010, the annual average temperature showed an increasing trend in the Qinghai Lake basin, at a rate of 0.32 °C/decade, and the annual precipitation showed obvious fluctuations with an average precipitation of 381.70 mm/year. Annual evaporation showed a decreasing trend (−30.80 mm/decade). The change in lake level was positively correlated to precipitation, surface runoff water and groundwater inflow into the lake and negatively correlated to evaporation from the lake surface. The total water consumption by human activities merely accounted for a very small part of precipitation, surface runoff inflow and groundwater inflow (1.97%) and of lake evaporation (1.87%) in Qinghai Lake basin. The annual water consumption of artificial afforestation and grass plantation accounting for 5.07% of total precipitation, surface runoff inflow and groundwater inflow and 5.43% of the lake evaporation. Therefore, the water level depended more on climatic factors than on anthropogenic factors.
Highlights
The Tibetan Plateau, known as the Qinghai-Tibetan Plateau, is the highest plateau in the world, with an average altitude of over 4000 m [1,2,3]; the permafrost over the Tibetan Plateau comprises approximately 70% of all of the permafrost regions in China [4]
Qinghai Lake is important for sustaining the ecological safety of the northeastern Tibetan Plateau [9], because it is a natural barrier to prevent the spread of the desertification of the west to the east, and as it has a significant influence on the climate in the Yellow River Basin [10]
The results revealed that water consumption by human activities had little effect on the water level in Qinghai Lake
Summary
The Tibetan Plateau, known as the Qinghai-Tibetan Plateau, is the highest plateau in the world, with an average altitude of over 4000 m [1,2,3]; the permafrost over the Tibetan Plateau comprises approximately 70% of all of the permafrost regions in China [4]. Qinghai Lake, the largest lake in China, is a special ecological function area in the northeastern Tibetan. Qinghai Lake is important for sustaining the ecological safety of the northeastern Tibetan Plateau [9], because it is a natural barrier to prevent the spread of the desertification of the west to the east, and as it has a significant influence on the climate in the Yellow River Basin [10]. Changes in the water level of Qinghai Lake directly affect the ecological system
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