Recent abnormal hydrologic behavior of Tibetan lakes inferred from
multi-mission altimetry and its driving force analyses
Abstract
The inland lakes in the Tibetan Plateau (TP), with closed catchments and
minimal human disturbance, are important indicators to climate change.
However, examination of the spatiotemporal patterns of the Tibetan lake
changes, especially for water level variation, was usually limited by
inadequate measurement accessibility. This obstacle has been remedied by
the developing satellite altimetry observations. The more recent studies
revealed the growth tendency of lakes in the central TP had been
decelerated or reversed during the period 2010-2016. It has not been
systematically investigated whether the deceleration or hiatus would
last in the following years thus far. This study aims to combine the
traditional and recently-advanced altimetry observations to update our
understanding of Tibetan lake changes in recent years. The results
reveal that water level changes of the 22 examined lakes showed abrupt
rises during the period 2016-2018, but the onsets and magnitudes of the
rises varied among the lakes. During the study period, the water level
of the nine lakes in the northern TP displayed a drastic rising trend
with an average rate of 0.82 m/a. In the central TP, the lake level
changes were generally divided into two categories. The water levels for
the lakes in the western CTP rose rapidly, while in the eastern CTP, the
lake water levels rose slowly with an average rising rate less than 0.40
m/a. The water levels for lakes in the northeastern TP and northwestern
TP kept a stably rising tendency. According to the results of climate
analysis, the spatial differences of the lake level rise rates were
primarily caused by the spatial and temporal changes of precipitation
over the TP, which may be related to the large-scale atmospheric
circulation affected by the El Niño and La Niña events.