A PEP III TRANSECT AS MODELED WITH A MACROPHYSICAL OR ARCHAEOCLIMATIC MODEL

About 95-99% of the monthly mean values of precipitation, temperature and potential evapotranspiration at individual places can be described as a non-linear function of the location of the "centers of action" specific to the sector of interest. These "centers of action" are the location of the subtropical anticyclones, the latitude of the jetstream, and the latitude of the ITCZ. This is the essence of synoptic climatology.

Using orbital forcing of the radiation arriving at the top of the atmosphere and the modulation of this radiation by the volcanic aerosol optical depth, the zonal mean surface temperature of the earth may be determined, and using standard dynamics, from this the 200 year average monthly latitudes of the appropriate circulation features have been determined . We have found that in Northern Europe the circulation pattern over North America must be considered since storms associated with the jetstream in North America often travel to Europe. The climate of Southern Europe is more nearly related to just the North Atlantic anticyclone, the jet over North Africa and the Mediterranean and the ITCZ in Africa because of the insertion of very moist air from the ITCZ region into the westerlies. This also applies to North Africa.

The oceanic subtropical anticyclones of the South Atlantic and Indian Oceans, the southern jetstream and the ITCZ positions in both Africa and the Indian sector suffice to model South African locations and the Antarctic region beyond. This is the method of climatic modeling we call "Archaeoclimatology".

Hundreds of places in this region have been modeled with this method yielding monthly 200 year mean values of precipitation and temperature, and also precipitation intensity, potential evapo-transpiration, snowfall, storm frequency (both westerly storms and tropical cyclones), and river discharge. A sampling, ranging from Novaya Zemlya to the Antarctic, will be presented.

Bryson, R.A. 1992 A Macrophysical Model of the Holocene Intertropical Convergence and Jetstream Positions and Rainfall for the Saharan Region. Meteorology and Atmospheric Physics 47:247-258.

Bryson, Reid A., and Robert U. Bryson 1997 Macrophysical Climatic Modeling of Africa’s Late Quaternary Climate: Site-Specific, High-Resolution Applications for Archaeology. African Archaeological Review 14(3):143-160.