Open AccessOn the hydrological cycle under paleoclimatic conditions as derived from AGCM simulations
Author(s) -
Lohmann Gerrit,
Lorenz Stephan
Publication year - 2000
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jd900189
Subject(s) - climatology , paleoclimatology , water cycle , last glacial maximum , thermohaline circulation , environmental science , atmospheric circulation , north atlantic deep water , quaternary , atmospheric sciences , climate model , geology , climate change , oceanography , holocene , ecology , paleontology , biology
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 paleoclimate and future climate changes.