Lake seasonality across the Tibetan Plateau and their varying relationship with regional mass changes and local hydrology

Abstract

The recent growth and deepening of inland lakes in the Tibetan Plateau (TP) may be a salient indicator of the consequences of climate change. The seasonal dynamics of these lakes is poorly understood despite this being potentially crucial for disentangling contributions from glacier melt and precipitation, which are all sensitive to climate, to lake water budget. Using in situ observations, satellite altimetry and gravimetry data, we identified two patterns of lake level seasonality. In the central, northern, and northeastern TP, lake levels are characterized by considerable increases during warm seasons and decreases during cold seasons, which is consistent with regional mass changes related to monsoon precipitation and evaporation. In the northwestern TP, however, lake levels exhibit dramatic increases during both warm and cold seasons, which deviate from regional mass changes. This appears to be more connected with high spring snowfall and large summer glacier melt. The variable lake level response to different drivers indicates heterogeneous sensitivity to climate change between the northwestern TP and other regions.

Extreme Lake Level Changes on the Tibetan Plateau Associated With the 2015/2016 El Niño

“…In normal years (e.g., 2013 and 2014), lake levels on the CTP increase considerably by 0.3–0.6 m during the summer monsoon season, with the highest level in middle to late September, then lake levels decrease gradually with the lowest level in early June (Lei et al, ). However, this seasonal pattern changed at all the observed lakes during the strong 2015/2016 El Niño event (Figure ).…”

“…Since glaciers are widely distributed on the NWTP, the insensitivity of lake dynamics on the NWTP to El Niño events may be partly attributed to higher contribution of glacier melt to lake level change. Lei et al () showed that although the total mass on the NWTP decreases due to decrease in precipitation in dry years, lakes can still expand rapidly in summer due to the large contribution of glacier melt to lake water budget.…”

Lake storage variation on the endorheic Tibetan Plateau and its attribution to climate change since the new millennium

“…Under negligible human disturbance, these alpine lakes act as 'sentinels' of regional climate change [5]. Influenced by strengthened westerlies through advection of heat and moisture, the CP has undergone evident wetting [6] and warming [7,8] during the recent decades, which posed inevitable impacts on the water budget in its alpine lakes [9,10].…”

“…For example, Zhang et al [16] applied ICESat altimetry and satellite imagery to quantify volume variations in 68 Tibetan lakes annually from 1989-2015. Yang et al [19] used satellite imagery and Digital Elevation Model (DEM) to estimate volume variations in 114 lakes at [5][6][7][8][9][10][11][12][13][14] year intervals during 1976-2013, but included only three discrete years (2000,2005 and 2013) after 2000. Lake dynamics varies across the CP and exhibits different changing rates during different periods.…”

Changing Moho Beneath the Tibetan Plateau Revealed by GRACE Observations

“…Since the glaciers are growing, the contribution of glacial meltwater to lake storage gain should be minimal in this area. Later Lei et al () concluded that the rapid expansion of the lakes in the central TP is mainly related to the significant increased precipitation in summer, rather than the melting of the glaciers (Lei et al, ). Therefore, we suggest that the significant negative signals in Region B are caused by other factors.…”