PROGRAM TITLE:	Global Change Research in Earth's Drylands
ACTIVITY STREAM:	Process Studies
SCIENCE ELEMENTS:	Solid-Earth Processes, Earth System History


SCIENTIFIC MERIT:  Over three-quarters of Earth's land surface is arid or 
semi-arid.  We are studying the interactions between landforms, soils, 
climate, and vegetation in these  environments in order to understand the 
relationships between dryland surface processes and both past and present 
climate variations.  Current long-term study  sites include locations in 
Africa, the Middle East, North America and Europe with plans to add sites 
in  South America.

The two major courses of study under this program focus on (1) dryland 
sediment transport and climate change, and (2) dryland vegetation dynamics 
and climate change.  Sediment transport studies encompass the effects of 
climate change on the rates, directions, and timing of  desert sand transport, 
and the development, preservation and erosion of dryland soils.  Vegetation 
dynamics studies include determining seasonal and longer-term reflectance 
variations due to vegetation and surface processes across a range of dryland 
environments.  The objective of these studies is to determine linkages 
between drought, sand transport, soil stability and vegetation dynamics, all 
of which are important components of change in areas prone to land 
degradation (desertification), deforestation, and consequent loss of 
ecological complexity.

The methodology used in these studies combines computer analysis of digital 
satellite data with ground observations and laboratory studies of the 
vegetation, soils and sediments from the field areas.  A combination of data 
from various sensor systems is used, depending on specific objectives of each 
study.  Heavy use is made of visible and reflected infrared wavelength 
multispectral image data (e.g., Landsat TM and MSS, SPOT, and AVHRR data) 
and imaging radar (e.g., Seasat and Shuttle Imaging Radar (SIR-A, -B, and -C).  
These studies include the development of baseline reflectance data and 
supporting field and lab work for dryland soils and vegetation in true desert 
(e.g. Egypt, Namibia), Sahelian grasslands (e.g. Mali) and tree and  shrub 
savanna (e.g. Kenya and Botswana).  Studies of temperate forest loss (e.g. 
Czechoslovakia) are conducted using similar techniques.

STAKEHOLDERS:  The research within this program of study involves U.S. 
and international collaborators.  These include scientists at the University 
of Arizona, the University of New Amphoras, Boston University, the 
University of New Hampshire, the National Aeronautics and Space 
Administration, and  colleagues in Egypt, Mali, Botswana, Kenya, Namibia 
and Czechoslovakia.  The research is directly related to the goals of several 
Core Projects within the IGBP, including LOICZ, BAHC, GCTE, PAGES, and 

POLICY RELEVANCE:  The program directly contributes to the study of two 
high-priority USGCRP milestones; specifically Forests and Deforestation, and 
Desertification; under Global  Water, Energy Cycles, and Sea Level Change:  
Linkages between climate and surface hydrologic conditions identified, 
Continental scale energy and water exchange  processes characterized for mid-
latitude regions, Watershed fluvial processes characterized.  Under Ecological 
Systems and Population Dynamics:  this program will contribute Decadal (and 
interdecadal) measurements of African deserts.


SI SGCR Representative:	Ted A. Maxwell
		NASM MRC 315
		Smithsonian Institution
		Washington, D.C.  20560
		202 357 1424
		FAX:  202 786 2566
Bureau Representative:	Pat Jacobberger
		NASM MRC 315
		Smithsonian Institution
		Washington, D.C.  20560
		202 357 1424
		FAX:  202 786 2566