Quaternary Tipping Points of Lake Systems in the Arid Zone of Central Asia (Q-TiP)

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.

Maps of the modelling domain and Qaidam basin
Q-TiP (Fig. 1): Maps of (a) the model domain, covering Central Asia and (b) the Qaidam Basin.

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.

Research Activities

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.

Map of net precipitation
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 simulations.

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.

Events

  • 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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Scientific partners at Universität Tübingen

Dr. Todd A. Ehlers

Dr. Svetlana Botsyun

Dr. Sebastian G. Mutz

Publications

Scherer, D. (2020):
Survival of the Qaidam mega-lake system under mid-Pliocene climates and its restoration under future climates. Hydrol. Earth Syst. Sci., 24, 3835–3850. DOI: 10.5194/hess-24-3835-2020.
Link

Schmidt, B., Wang, X., Mutz, S., Botsyun, S., Ehlers, T., Scherer, D. (2020):
Changes in water balance of the Qaidam Basin from Pliocene to present day. EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20666. DOI: 10.5194/egusphere-egu2020-20666.
Link