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The Effect of SW Drought on Precipitation of Evapotranspired Origin. Francina Dominguez 1,2 Juan Camilo Villegas 3,4 David D. Breshears 3. 1.Hydrology and Water Resources 2.Atmospheric Sciences 3.School of Natural Resources 4.Universidad de Antioquia, Colombia.
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The Effect of SW Drought on Precipitation of Evapotranspired Origin Francina Dominguez1,2 Juan Camilo Villegas3,4 David D. Breshears3 1.Hydrology and Water Resources 2.Atmospheric Sciences 3.School of Natural Resources 4.Universidad de Antioquia, Colombia
The goal is to understand how hydrologic variability in the Southwest affects the export of moisture Dynamic precipitation recycling model Export of Moisture from the SW Region Effect of SW Drought on subsequent Precipitation
atmospheric surface sub surface The atmospheric paths of moisture that connect hydrologic units are poorly understood. What are the effects of changes in atmospheric hydrologic connectivity? “Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. (Pringle, 2001)
Dynamic Precipitation Recycling Model Dominguez, F. et al., 2006. J. Climate Dynamic Recycling Model
The principle for all analytic recycling models is the conservation of atmospheric moisture In the past, recycling models have assumed that the change in moisture storage is negligible. New model relaxes this assumption R = r (local recycling ratio) w = w(precipitable water) e = E(evapotranspiration) Dynamic Recycling Model
In order to solve the equation we change the coordinate system to follow the motion of the air. To solve, change coordinate system. We basically follow the path of the air. The equation becomes a simple ODE. R = r (local recycling ratio) w = w(precipitable water) e = E(evapotranspiration) Dynamic Recycling Model
In addition to recycling ratios, we can calculate source-sink regions of atmospheric moisture. Dynamic Recycling Model
What is the spatial extent of precipitation originating as ET from the South Western US? North American Regional Reanalysis (NARR) data. Warm season (Apr-Sep) ? Export of SW ET
Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Evapotranspiration from the South West affects precipitation across the United States. Precipitation originating as ET from SW region. Jul 1-15 (1996-1999) Export of SW ET
Evapotranspiration from the South West affects precipitation across the United States. Precipitation originating as ET from SW region. Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Jul 16-31 (1996-1999) Export of SW ET
At the peak of the Monsoon season, we see a peak in recycled precipitation. Precipitation originating as ET from SW region. Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Aug 1-15 (1996-1999) Export of SW ET
At the peak of the Monsoon season, we see a peak in recycled precipitation. Precipitation originating as ET from SW region. Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Aug 16-31 (1996-1999) Export of SW ET
Toward the end of the Monsoon, RP diminishes. Precipitation originating as ET from SW region. Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Sep 1-15 (1996-1999) Export of SW ET
Toward the end of the Monsoon, RP diminishes. Precipitation originating as ET from SW region. Percent of total Precipitation (falling in each pixel) that originates as ET from SW region. Sep 16-30 (1996-1999) Export of SW ET
Jul – Sep ET andPP NDVI NDVI for late May-June the region encompassing P. edulis (Breshears et al.,2005) Effects of Southwest drought on subsequent precipitation of evapotranspired origin. Even though NARR doesn’t account for vegetation variability, ET varies as NDVI.
Precipitation originating as ET from 4-Corners Region varies in agreement with evapotranspiration. Drought and Recycling
Drought Transition Severe Drought The drought period presented a sharp decrease in precipitation originating as ET. Pre-Drought Drought and Recycling
This meant that the % of precipitation originating as SW-ET considerably diminished during the drought. Drought Transition Severe Drought Pre-Drought Drought and Recycling
Adjacent states receive approximately 10% of their Jul-Sep precipitation from the Southwest. This value dropped to around 6% during the drought Drought and Recycling
The recent SW drought had a significant impact on the precipitation originating as ET from the SW region. In conclusion… The Dynamic Recycling Model has enabled us to analyze the regions where ET from the Southwest contributes to precipitation. Including intraseasonal variability. Conclusions
NARR doesn’t include vegetation variability, hence doesn’t account for the regional-scale die-off. Could the vegetation die-off amplify the effect of the drought on remote precipitation? Further Thoughts…