Enhancement of dust source area during past glacial periods due to changes of the Hadley circulation

Tropical deserts (e.g., Sahara, Arabian desert, Australian desert) are located within the Hadley circulation. Most of the dust uplifted from these deserts is carried by trade winds and deposited in tropical oceans with very little, if any, transported to polar regions. During glacial periods the dust concentrations in polar ice cores were a factor of 10 to 100 higher than during interglacial periods, including the current Holocene. The early general circulation model simulations of the past glacial climate were not able to reproduce these high mineral dust concentrations; the most recent attempts achieve an increased dust transport to polar regions by extending dust source areas to higher latitudes. We present a hypothesis that during glacial periods the Hadley cell is confined closer to the equator. This contraction of the Hadley circulation leads to the geographical change of the boundary between the tropical and the midlatitude circulation regimes. During the glacial periods a considerable fraction of the current tropical deserts was located outside the region of the Hadley circulation. This allowed the dust to be uplifted and transported by midlatitude storm systems to the polar regions. We present a model for the contraction of the Hadley circulation during the past glacial periods based on the Schneider-Lindzen and Held-Hou model of symmetric tropical circulation and on the assumption that the tropical sea surface temperatures were lower during glacial periods than they are today.

[1]  J. Coakley,et al.  Response of the NCAR Community Climate Model to the Radiative Forcing by the Naturally Occurring Tropospheric Aerosol , 1985 .

[2]  C. Genthon,et al.  Simulations of desert dust and sea-salt aerosols in Antarctica with a general circulation model of the atmosphere , 1992 .

[3]  Sandy P. Harrison,et al.  Dust sources and deposition during the last glacial maximum and current climate: A comparison of model results with paleodata from ice cores and marine sediments , 1999 .

[4]  F. Grousset,et al.  Patagonian origin of glacial dust deposited in East Antarctica (Vostok and Dome C) during glacial stages 2, 4 and 6 , 1997 .

[5]  P. Bloomfield,et al.  Changes in Atmospheric Circulation and Ocean Ice Cover over the North Atlantic During the Last 41,000 Years , 1994, Science.

[6]  Richard A Lindzen.  Dynamics in Atmospheric Physics: Symmetric circulation models , 1990 .

[7]  R. Garcia,et al.  A detailed evaluation of the stratospheric heat budget: 2. Global radiation balance and diabatic circulations , 1999 .

[8]  B. Hunt.  The Influence of the Earth's Rotation Rate on the General Circulation of the Atmosphere , 1979 .

[9]  Brian J. Hoskins,et al.  The tropical tropopause , 1998 .

[10]  M. Satoh.  Hadley Circulations in Radiative–Convective Equilibrium in an Axially Symmetric Atmosphere , 1994 .

[11]  David Rind,et al.  The Effects of Physical Processes on the Hadley Circulation. , 1984 .

[12]  Dale A. Gillette,et al.  A wind tunnel simulation of the erosion of soil: Effect of soil texture, sandblasting, wind speed, and soil consolidation on dust production , 1978 .

[13]  B. Farrell.  Equable Climate Dynamics , 1990 .

[14]  G. Jenkins.  A sensitivity study of changes in Earth's rotation rate with an atmospheric general circulation model , 1996 .

[15]  N. McFarlane,et al.  The mineral dust aerosol cycle during the Last Glacial Maximum , 1999 .

[16]  G. Ramstein,et al.  Tropical paleoclimates at the Last Glacial Maximum: comparison of Paleoclimate Modeling Intercomparison Project (PMIP) simulations and paleodata , 1999 .

[17]  G. Craig,et al.  GCM Tests of Theories for the Height of the Tropopause , 1997 .

[18]  C. Sonett,et al.  Late Proterozoic and Paleozoic Tides, Retreat of the Moon, and Rotation of the Earth , 1996, Science.

[19]  J. Coakley,et al.  Aerosols and Climate , 1974, Science.

[20]  Irina N. Sokolik,et al.  Direct radiative forcing by anthropogenic airborne mineral aerosols , 1996, Nature.

[21]  J. Beck,et al.  Abrupt changes in early Holocene tropical sea surface temperature derived from coral records , 1997, Nature.

[22]  N. Nicholls,et al.  Evolution of late pleistocene and holocene climates in the circum-south pacific land areas , 1992 .

[23]  C. Genthon,et al.  Atmospheric dust under glacial and interglacial conditions , 1998 .

[24]  J. Jouzel,et al.  Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica , 1999, Nature.

[25]  M. Mishchenko,et al.  Modeling phase functions for dustlike tropospheric aerosols using a shape mixture of randomly oriented polydisperse spheroids , 1997 .

[26]  J. Petit,et al.  Insoluble particles in Antarctic ice: Background aerosol size distribution and diatom concentration , 1988 .

[27]  J. Overpeck,et al.  Possible role of dust-induced regional warming in abrupt climate change during the last glacial period , 1996, Nature.

[28]  J. Steffensen.  The size distribution of microparticles from selected segments of the Greenland Ice Core Project ice core representing different climatic periods , 1997 .

[29]  R. Healy,et al.  Influence of ocean heat transport on the climate of the Last Glacial Maximum , 1997, Nature.

[30]  D. Rind.  Dependence of Warm and Cold Climate Depiction on Climate Model Resolution , 1988 .

[31]  Minghua Zhang,et al.  Analysis of the atmospheric energy budget: A consistency study of available data sets , 1999 .

[32]  Ulrike Lohmann,et al.  Influence of cirrus cloud radiative forcing on climate and climate sensitivity in a general circulation model , 1995 .

[33]  G. d’Almeida,et al.  On the variability of desert aerosol radiative characteristics , 1987 .

[34]  D. Rind,et al.  Influence of the latitudinal temperature gradient on soil dust concentration and deposition in Greenland , 2000 .

[35]  J. Jouzel,et al.  A 30,000-yr isotope climatic record from Antarctic ice , 1979, Nature.

[36]  Arthur Y. Hou,et al.  Nonlinear axially symmetric circulations in a nearly inviscid atmosphere , 1980 .

[37]  Gilles Bergametti,et al.  Submicron desert dusts: A sandblasting process , 1990 .