Publication Date:
2013-03-09
Description:
The Gulf of Mexico (GOM) is facing large pressures from environmental changes since the beginning of last century. However, the magnitude and long-term trend of total water discharge to the GOM and the underlying processes are not well understood. In this study, the Dynamic Land Ecosystem Model (DLEM) has been improved and applied to investigate spatial and temporal variations of evapotranspiration (ET) and runoff (R) over drainage basins of the GOM during 1901-2008. Modeled ET and discharge were evaluated against up-scaled data sets and gauge observations. Simulated results demonstrated a significant decrease in ET at a rate of 15 mm yr -1 century -1 and an insignificant trend in runoff/precipitation (R/P) and river discharge over the whole region during 1901-2008. However, the trends in estimated water fluxes show substantial spatial and temporal heterogeneities across the study region. Generally, in the west arid area, ET, R, and R/P decreased; while they increased in the eastern part of the study area during the last 108 years. In the resent 30 years this region experienced substantial decrease in R. Factorial simulation experiments indicate that climate change, particularly P, was the dominant factor controlling interannual variations of ET and R; while land use change had the same magnitude of effects on long-term trends in water fluxes as climate change did. To eliminate modeling uncertainties, high-resolution historical meteorological data sets and model parameterizations on anthropogenic effects such as water use and dam constructions should be developed.
Print ISSN:
0043-1397
Electronic ISSN:
1944-7973
Topics:
Architecture, Civil Engineering, Surveying
,
Geography
Permalink
