Background
GEWEX Americas Prediction Project (GAPP)
The GAPP program (GEWEX [Global Energy and Water Cycle Experiment] America Prediction
Project) objectives are to make monthly to seasonal predictions of the hydrological
cycle and to use these improved predictions for better water resources management.
The first objective largely involves improving the land surface, hydrology, and
boundary layer representations of models used for climate prediction through improved
understanding of the hydrological processes, feedbacks between the land and atmosphere,
model transferability, and development of a comprehensive modeling system.
The second objective involves scaling the climate model output to make it useful
for water resource managers, improved understanding of the links between hydrologic
predictions and water resources management, including the use of demonstration projects,
and better understanding of the effects of land surface changes on the regional hydrology.
Two major new initiatives will be the effect of orography on the hydrological cycle of
the Western Cordillera and the predictability of the North American Monsoon (NAMS) and
its effects on summer precipitation over the USA.
The other components all relate to improving the predictability of the hydrological
cycle with special regards to the land surface and the role of predictions for water
resources management
Climate Variability and Predictability (CLIVAR) Pan-American Climate Studies (PACS)
The principal goal of the CLIVAR
PACS is to extend the scope and
improve the skill of operational seasonal-to-interdecadal climate prediction over the
Americas. Several of the important climate features of this region include the warm
season rainfall and extreme weather events, such as hurricanes and torrential rain
falls. The climate of the region is dominated by the intertropical convergence zones
(ITCZ) over the eastern Pacific and equatorial Atlantic and by the monsoons over the land
regions. Current research supported by CLIVAR PACS has the following scientific goals:
- Identify cause-and-effect relationships for monsoon modulation on time scales from
seasonal to interdecadal, including teleconnection patterns that span the Pan American region;
- Model the structure and evolution of the eastern tropical Pacific Sea Surface Temperature
(SST) field, the ITCZ/cold tongue complex and subtropical stratus cloud decks and their influence
on climate over the Americas;
- Define dynamical processes responsible for the onset, demise and character of the
continental-scale monsoon over South America.
Resources
GEWEX (Global Energy and Water Cycle Experiment)
Climate Variability and Predictability (CLIVAR)
NASA Land Surface Hydrology Research Program
U.S. Global Change Research Program Water Cycle Study Group
