• On the hydrological cycle under paleoclimatic conditions as derived from AGCM simulations.
  • Gerrit Lohmann, Stephan Lorenz

    Journal of Geophysical Research (Climate and Physics of the Atmosphere)

    105 (D13), 17,417-436.

      The atmospheric hydrological cycle is compared for different time slices of the late Quaternary. Simulations have been conducted with an atmospheric circulation model at T42 resolution, and we have performed a global evaluation of the atmospheric water vapor transport. The water export from the Atlantic catchment area, important for driving the large-scale thermohaline ocean circulation, is analyzed in detail. For the Last Glacial Maximum (LGM), we examine the model's sensitivity with respect to tropical cooling relative to the CLIMAP reconstruction which is motivated by recent data. We find that the LGM experiment with tropical cooling is in better agreement with proxy data available. Our experiments indicate that the water vapor transport is strongly affected by three mechanisms: Continental drying, eddy moisture transport, and changes in the tropical circulation. Except for the continental drying and the blocking effect of the Laurentide ice sheet, the hydrological cycle is substancially different for both LGM experiments. We find that the hydrological system is rather sensitive to tropical temperature change which is important to understand paleo and future climate changes.

    -> available as AGU pdf file (HUGE !)

    -> available as AGU style PostScript file (HUGE !)

      Figure of solar radiation for the time slices considered
      Link to On the global water cycle and the thermohaline circulation
      ECHAM 3: Technical Report No. 6, DKRZ, 1993: plain PostScript file (Huge !)
      goto Centennial and longer time scale variability
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