[Insert Figure 9 here]

4 Conclusions

The more recent studies benefiting from the longer and finer observations revealed the growth tendency of lakes in the central TP had been decelerated or reversed during the period 2010-2016. However, whether the deceleration or hiatus would last in the following years remains unclear. It has not been systematically investigated thus far. Thus, in this study, 22 large inland lakes were investigated to update our understanding of the changing characteristics of Tibetan lakes during the period 2016-2018 by combining the traditional and recently-advanced radar altimetry measurements. Furthermore, we will explore the potential climate driving mechanism of the recent varying tendency of lake changes in the TP. For most lakes in the TP, lake levels showed an abrupt rise during 2016-2018, compared with the earlier stage during 2010-2016, but the onsets and magnitudes of water level rise varied with subzones and lakes.
Our results reveal that the lake water levels in the NTP displayed a sharply rise with an average rate of 0.90 m/a except Kusai Lake (outburst of its upstream lake). In the central TP, the lake level changes are divided into two categories during the period 2016-2018, which is different from the dramatic increasing pattern for lakes in the northern TP. The water level for Qinghai Lake in the northeastern TP kept a stable growth tendency during the recent years, reaching 0.47m/a. The water level rising rates for the three lakes in the northwestern TP (LumajangdongCo, Jieze Caka and Heishibei Lake) are extremely different from each other. The spatial differences of the lake level rise rates were primarily caused by the changes of precipitation over the TP, which may be related to the large-scale atmospheric circulation. The atmospheric circulations such as ENSO and AO may contribute to the anomalous precipitation by driving water vapor transport of TP, but vary with different years. Although this study could be beneficial for our understanding of the driving mechanism of the rapid water level rise of Tibetan lakes and hydrological cycle under future climate change conditions, more comprehensive investigations of precise physical processes are required to clarify the climate-driven mechanism of Tibetan lake level changes in the further study.Acknowledgments:
This work was partly funded by the Second Tibetan Plateau Scientific Expedition and Research (2019QZKK0202), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA23100102), the National Key Research and Development Program of China (Grant No. 2019YFA0607101, 2018YFD0900804, 2018YFD1100101), the Thousand Young Talents Program in China (Grant No. Y7QR011001), and the National Natural Science Foundation of China (No. 41971403, 41801321). We are also grateful to the Laboratoire d’Etudes en Géophysique et Océanographie Spatiales (LEGOS), the Hydrological Time Series of Inland Waters (DAHITI), the NASA EOSDIS Physical Oceanography Distributed Active Archive Center (PO.DAAC), Centre National d’Etudes Spatiales (CNES), the China Meteorological Data Sharing Service System and the European Centre for Medium-Range Weather Forecasts for providing satellite altimetry data and meteorological data for this study.

Data Availability Statement

Hydroweb data and DAHITI data are downloaded from the Hydroweb service (http://hydroweb.theia‐land.fr) and the DAHITI service (https://dahiti.dgfi.tum.de/en), respectively. We can download the SARAL data from ftp://avisoftp.cnes.fr and Sentinel-3 data from https://sentinel.esa.int/web/sentinel/sentinel-data-access. The precipitation data and ERA-interim reanalysis data are collected from the China Meteorological Network (http://data. cma.cn) and the NOAA Physical Sciences Laboratory (https://psl.noaa.gov/data/gridded/data.erainterim.html).
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