Quaternary Tipping Points of Lake Systems in the Arid Zone of Central
The research project Q-TiP - Quaternary Tipping Points of Lake Systems
in the Arid Zone of Central Asia is part of the CAME II program funded
by the Federal Ministry of Education and Research (BMBF).
The Qaidam Drainage Basin (QB) is an intermontane endorheic basin
located in the northeastern Tibetan Plateau. The central lower
part of the QB features hyperarid climate conditions today. But
paleogeographic studies revealed that the QB once contained a
freshwater mega-lake system during the mid-Pliocene (∼3.3–3.0 Ma BP),
even though the surrounding regions showed increasingly arid climates.
With the onset of the Pleistocene glaciations at ca. 2.6 Ma BP, lakes
began to shrink and finally disappeared almost completely. The question
of how the mega-lake system was able to withstand the regional trend of
aridification for such a long time has remained enigmatic so far.
Q-TiP (Fig. 1): Maps of (a) the model domain, covering Central Asia
and (b) the Qaidam Basin.
- ©TU Berlin
The existence of a mega-lake system during the Pliocene implies that long-term
mean annual water balance, i.e. the total annual change in terrestrial water
storage within the basin's reservoirs (aquifers, soils, lakes, rivers,
permafrost, snow covers, glaciers, etc.), was close to zero and did not show,
on average, negative values over periods of thousands of years or longer,
because otherwise the mega-lake system would have temporarily dried out and
produced layers of evaporites.
This research project addresses the question of how long-term mean annual
water balance in the QB could have been zero or even positive over the
whole period under very dry climates such that a mega-lake system could
have been sustained. We examine the sensitivity of the water balance to
changing temperatures and specific humidity. This allows for a first-
order estimate of the water balance under different climates like those
in the mid-Pliocene or the future. We also compare models of the
atmospheric conditions of today and of the mid-Pliocene to assess the
differences of the water balance of the QB and of atmospheric water
transport in central Asia, to determine the large scale controlling
mechanisms that regulate these differences. This research is based on
the state-of-the-art Weather Research and Forecasting (WRF-ARW) modelling
system and carried out in close cooperation with the University of Tübingen.
Q-TiP (Fig. 2): Maps of simulated net precipitation values in and
around Qaidam Basin for (a) Pliocene conditions, (b) present-day
conditions and (c) the difference of pliocene and present-day
- ©TU Berlin
Since the mid-Pliocene is often regarded as a past analogue for modern
climate changes, our studies also intend to provide a rational basis for
assessing environmental changes that might be caused by climate changes
as projected in this region for the future.
- 12.09-13.09.2019, Frankfurt a.M.: Final meeting
- 20.02.2019, Frankfurt a.M.: Q-TiP meeting
- 24.10-25.10.2018, Frankfurt a.M.: Joint CAME II
meeting and Q-Tip meeting
- 28.02.2018, Frankfurt a.M.: Q-Tip meeting
- 18.10-19.10.2017: Joint CAME II meeting and Q-Tip meeting
- 01.03.2017, Frankfurt a.M.: Q-Tip meeting
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