资源环境科技发展态势分析平台

Lake level change is an effective indicator of climate change, because it reflects the dynamic balance of water input and loss. Here we provide a first look of Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) on the lakes of the Tibetan Plateau. ICESat-2 doubles the number of lakes observed using predecessor ICESat data. The ICESat/ICESat-2 altimetry data between 2003 and 2018 are in excellent agreement with in situ measurements from Qinghai Lake (R-2 = 0.95, root-mean-square error = 0.10 m) and with gauge observations made on 3 December 2018 (< 2 cm). The 62 lakes examined show a mean rate of water level change of 0.28 +/- 0.03 m/year in 2003-2018, with 58 lakes increasing (mean rate 0.30 +/- 0.03 m/year), and 4 lakes decreasing (mean rate -0.12 +/- 0.06 m/year). A total change of lake water storage of similar to 14 Gt/year is estimated. The results suggest that ICESat-2 data will be an important tool for future lake level change studies.

Plain Language Summary The Tibetan Plateau contains many lakes that are changing in depth and size due to the climate warming that has been particularly rapid in this region. Because of the lack of water level gauges in this remote area, satellites provide the only practical tool of monitoring these lakes' changes. A new altimetry satellite, Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), which has several improvements for monitoring lakes, was launched in 2018; we are reporting the first outlook of the new data to assess its potential for lake level changes on the Tibetan Plateau. We found that the new data allowed us to study more lakes than was previously possible, and the data compared well with traditional water level measurements. By carefully combining the new data with older ICESat and Landsat images, we are able to assess how the lake levels and water storage had changed over the period 2003 to 2018. Out of the 62 lakes studied, 58 had an increase in water level over this period, with only 4 lakes showing a decrease. The ability of the ICESat-2 data to provide this information, suggests that, when the data become routinely available in the future, real-time monitoring of these lakes may be possible.