100 years of lake evolution over the Qinghai–Tibet Plateau

Guoqing Zhang,Wei Luo,Wei Wan,Youhua Ran,Wenfeng Chen,Xin Li,Fenglin Xu

doi:10.5194/essd-13-3951-2021

Abstract

Abstract. Lakes can be effective indicators of climate change, and this is especially so for the lakes over the Qinghai–Tibet Plateau (QTP), the highest plateau in the world, which undergoes little direct human influence. The QTP has warmed at twice the mean global rate, and the lakes there respond rapidly to climate and cryosphere changes. The QTP has ∼ 1200 lakes larger than 1 km2 with a total area of ∼ 46 000 km2, accounting for approximately half the number and area of lakes in China. The lakes over the QTP have been selected as an essential example for global lakes or water body studies. However, concerning lake data over the QTP are limited to the Landsat era and/or available at sparse intervals. Here, we extend the record to provide comprehensive lake evolution data sets covering the past 100 years (from 1920 to 2020). Lake mapping in 1920 was derived from an early map of the Republic of China and in 1960 from the topographic map of China. The densest lake inventories produced so far between 1970 and 2020 (covering all lakes larger than 1 km2 in 14 epochs) are mapped from Landsat MSS, TM, ETM+, and OLI images. The lake evolution shows remarkable transitions between four phases: significant shrinkage in 1920–1995, rapid linear increase in 1995–2010, relative stability in 2010–2015, and further increase in 2015–2020. The spatial pattern indicates that the majority of lakes shrank in 1920–1995 and expanded in 1995–2020, with a dominant enlargement for central-north lakes in contrast to contraction for southern lakes in 1976–2020. The time series of precipitation between 1920 and 2017 indirectly supports the evolution trends of lakes identified in this study. The lake data set is freely available at https://doi.org/10.5281/zenodo.4678104 (Zhang et al., 2021a).

Highlights

The Qinghai–Tibet Plateau (QTP) is the highest plateau in the world and has a large number of lakes widely distributed across it
The number of lakes larger than 1 km2 increased to 1107 in 1960, but their total area decreased to 38 314.51 km2, a 6 % drop relative to the area in 1920
The great increase in number may be attributed to the appearance of new lakes such as those detected by multi-period satellite images (Ma et al, 2010; Zhang et al, 2020b)

Summary

Introduction

The Qinghai–Tibet Plateau (QTP) is the highest plateau in the world and has a large number of lakes widely distributed across it. Cryospheric melting is reflected in accelerated glacier retreat and ice loss (Yao et al, 2012; Shean et al, 2020; Hugonnet et al, 2021), a lower snowline (Shu et al, 2021), permafrost thawing and degradation (Ran et al, 2018), and snowmelt (Pulliainen et al, 2020), which feeds crucial water to alpine lakes. Human effects on these alpine lakes’ evolution can be considered to be negligible, due to their remoteness and the harsh weather conditions. These lakes respond rapidly to climate and cryosphere changes, as most of them are located

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Discussion

Conclusion