Variations in Permafrost Temperature and Stability of Alpine Meadows in the Source Area of the Datong River, Northeastern Qinghai‐Tibet Plateau, China

Abstract

ABSTRACTZonal alpine meadow is widespread in the source area of the Datong River, northeastern Qinghai‐Tibet Plateau, China, and can be divided into typical meadow and swamp meadow, according to variations in the soil moisture content. A total of 56 measurements of the mean annual ground temperature (MAGT) revealed a significant difference in the MAGT of the two vegetation types. The measured MAGT varied from ‐2.8 to 0.46°C in the swamp meadow, and from ‐0.6 to 2.5°C in the typical meadow. Measurements of 0°C were found at approximately 3710 m asl and 3660 m asl in the typical meadow and swamp meadow, respectively. Using the measured MAGT and calculated topo‐climatic parameters as dependent and independent variables, two statistical models of MAGT were constructed for each vegetation type. The calculated results were classified into different zones and types to determine the permafrost stability in different vegetated areas. Semi‐stable permafrost (‐3.0°C <MAGT ≤ ‐1.5°C) and transitory permafrost (‐1.5°C <MAGT ≤ ‐0.5°C) were the two predominant permafrost types in the swamp meadow, whereas unstable permafrost (‐0.5°C <MAGT ≤ +0.5°C) and seasonally frozen ground (MAGT >0.5°C) were the two main types in the typical meadow. The differences in permafrost temperatures and stability between the two vegetation types can be explained by the local environmental characteristics, including vegetation cover and soil water content. Copyright © 2014 John Wiley & Sons, Ltd.