Prince, Stephen (Steve): University of Maryland (Project Lead)
Xue, Yongkang: UCLA (Co-Investigator)
Project Funding:
2008 - 2011
NRA: 2007 NASA: Terrestrial Ecology
Funded by NASA
Abstract:
This study will
investigate the dynamics of vegetation in the Sudano-Sahelian region of
Africa to improve the understanding of dryland ecosystems functions and
interactions with the climate. Regional vegetation productivity and
phenology and their environmental correlations are well-known, but the
mechanisms are little understood at this scale, and unexplained
relationships challenge current understanding. The effects of important
aspects of dryland environments, such as episodic rainfall pulses, are
little known at this scale. Time lags between pulses of rainfall, for
example, presumably have a threshold beyond which the vegetation does
not respond. Extensive areas with poor correlations between annual
vegetation growth and rainfall have been reported, notwithstanding the
existence of strong regional correlations. Current knowledge of surface
water and energy fluxes suggests that these anomalies will affect the
climate. The objectives are: 1) Systematically survey and inventory
periodicities in vegetation cover, leaf are index and net production
for 27+yrs using high temporal resolution satellite data; 2) Form
hypotheses about endogenous and environmental causes of the various
types of vegetation dynamics, develop algorithms relating the two, and
define new plant functional type properties; 3) Modify an existing,
coupled soil-vegetation-atmosphere-transfer model (SSiB-4) and a
dynamic vegetation model (TRIFFID) to simulate observed vegetation
dynamics and use a mesoscale climate model (WRF) to determine the
impact on the regional climate. The West African monsoon has not been
modeled satisfactorily, and evidence indicates that poor specification
of vegetation processes contributes to the inaccuracy. We intend to
make a more complete description of the principal temporal and spatial
patterns of variation in vegetation in the Sudano-Sahelian region, to
assess the roles of endogenous and exogenous environmental processes,
including anthropogenic land cover changes, and to determine their
effects on the regional climate. Significant improvements in
understanding dryland ecosystem processes at the regional scale and its
climate are anticipated.
2015 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- The effects of anthropogenic degradation of rangelands on carbon sequestration in the southwestern drylands of U.S.A.
-- (Praveen Noojipady, Stephen D Prince, Khaldoun Rishmawi)
[abstract]
2011 NASA Carbon Cycle & Ecosystems Joint Science Workshop Poster(s)
- External Climate Forcings and Vegetation Interannual and Decadal Variability in West Africa and North America
-- (Yongkang Xue, Guoqiong Song, Zhengqiu Zhang, Peter Cox, Stephen D Prince, Glen MacDonald, George James Collatz)
[abstract]
2010 NASA Terrestrial Ecology Science Team Meeting Poster(s)
- Vegetation dynamics in drylands and implications for regional climate: analysis of two decades of observations in the African Sahel
-- (Steve Prince, Yongkang Xue, Khaldoun Rishmawi)
[abstract]
[poster]
- Ecosystem and climate variability in West Africa – a study using the SSiB4/TRIFFID biophysical/dynamic vegetation model
-- (Yongkang Xue, Guoqiong Song, Peter Cox, Steve Prince)
[abstract]
More details may be found in the following project profile(s):
