Shrinking thermokarst lakes and ponds on the northeastern Qinghai‐Tibet plateau over the past three decades

Abstract

Identifying the changes in thermokarst lake dynamics has a significant contribution to landscape‐scale hydrology, ecology, and assessment of carbon budgets in permafrost regions. Changes in the number and areal extent of thermokarst lakes and ponds were quantified in a representative permafrost area (150 km2) in the south‐central Headwater Area of the Yellow River (HAYR). Water‐body inventories were generated from Landsat satellite imageries using the supervised Maximum Likelihood Classification method for three periods: 1986, 2000, and 2015. From 1986 to 2015, the number of water bodies larger than 0.36 ha decreased by 40% (461–277), while the total surface area decreased by 25% (542–406 ha). The ponds category (smaller than 1 ha) recorded the most substantial change, as their number decreased by 44% and their water‐surface area by 41%. Many lakes disintegrated, partially drained, and formed several remnant ponds, while the majority of the ponds did not drain completely, but shrank below 0.36 ha. These shrinking patterns are consistent with the warming climate in the HAYR, which suggests intense permafrost degradation. Future research will be focused on a better understanding of water–heat dynamics of thermokarst lakes and ponds in association with permafrost degradation at a landscape scale.

Quantification of Water Released by Thawing Permafrost in the Source Region of the Yangtze River on the Tibetan Plateau by InSAR Monitoring

“…Many long‐term effects of permafrost thaw, for example, the reorganization of vegetation, hydraulic connections, and flow paths also have impacts on regional hydrology (Jorgenson et al., 2013; Walvoord & Kurylyk, 2016). Numerous thermokarst ponds/lakes are spread over the study area (Wei et al., 2021), and lake water might be quickly drained when the permafrost at the bottom of the lake is thaw penetrated (Jones & Arp, 2015; L. C. Smith et al., 2005; Șerban et al., 2021). These processes are not in the scope of this study and are not considered.…”

“…Numerous thermokarst ponds/lakes are spread over the study area (Wei et al, 2021), and lake water might be quickly drained when the permafrost at the bottom of the lake is thaw penetrated (Jones & Arp, 2015;L. C. Smith et al, 2005;Șerban et al, 2021). These processes are not in the scope of this study and are not considered.…”

Pervasive Permafrost Thaw Exacerbates Future Risk of Water Shortage Across the Tibetan Plateau

“…The recently observed widespread lake drainage across the Arctic due to permafrost thaw (Webb et al., 2022) might also occur on the TP in the future, despite the expansion of endorheic lakes on the TP due to increased P and cryospheric meltwater over the past few decades (T. Yao et al., 2022; Zhang et al., 2017). The recent shrinkage or even disappearance of the thermokarst lakes in the source area of the Yellow River where permafrost thaws rapidly (Șerban et al., 2021) could be an early warning signal of potential future lake shrinkage across the TP due to pervasive permafrost thaw.…”

Impacts of Permafrost Degradation on Hydrology and Vegetation in the Source Area of the Yellow River on Northeastern Qinghai-Tibet Plateau, Southwest China

“…The number of lakes greater than six hectares (>0.06 km 2 ) decreased from 405 to 261 in Madoi County from 1990 to 2000 (Dong et al, 2009). Small lakes were extremely unstable because of their small area, shallow water depths, and high susceptibility to disturbances (Watts et al, 2014;Luo et al, 2020c;Șerban et al, 2020;Șerban et al, 2021). Since the 21st century, especially after 2004, the area and number of lakes have begun to increase, possibly due to the increased water resources replenished by ground ice meltwater (Li et al, 2008).…”