Qaidam Basin

The Qaidam Basin is an endorheic (internally drained) basin on the northeastern Tibetan Plateau in Central Asia. Today it is one of the most arid regions in China, characterized by salt flats and playas. Geological evidence indicates that during the Mid-Pliocene, the basin hosted a large perennial lake system.

The paleoclimate question

The existence of the mega-lake implies a substantially different Water balance in the Pliocene: either much higher Precipitation, much lower evapotranspiration, or both. Understanding what climate conditions sustained the lake has implications for:

• Tibetan Plateau uplift history and its effect on Asian monsoon dynamics
• Global climate sensitivity during warm periods (Pliocene CO2 levels were ~400 ppm, comparable to today)
• The response of Central Asian water resources to future warming

Research findings

Wang, Schmidt et al. (2021, JGR-Atmospheres) used Dynamical downscaling with WRF to simulate the Qaidam Basin water balance under both present-day and Mid-Pliocene boundary conditions. The Pliocene simulations used modified topography (lower Tibetan Plateau) and warmer SSTs from PlioMIP experiments.

Key findings:

1. Under Pliocene conditions, precipitation over the basin increased due to enhanced moisture transport and altered monsoon circulation linked to topographic differences.
2. Although evapotranspiration increased under warmer conditions, the net water-balance tendency shifted toward lake-supporting conditions.
3. Sensitivity analysis indicated that topographic changes were a dominant control alongside broader climate forcing.

This was one of the first studies to apply high-resolution regional climate modeling to constrain Pliocene water budgets, demonstrating that Dynamical downscaling can provide physically consistent water balance estimates in regions where proxy data are sparse.

The work was first presented at EGU 2020 (Schmidt, Wang et al., EGU General Assembly) and published as a preprint in ESS Open Archive before the final journal publication.

See also: Water balance, Dynamical downscaling, ERA5 reanalysis