Transcript Project Years 2 and 3, only

National Drought Monitoring System for Drought Early Warning Using Hydrologic
and Ecologic Observations from NASA Satellite Data
(Project Years 2 and 3, only)
G. Robert Brakenridge, Co-Investigator
Dartmouth Flood Observatory
Depts. Geography and Earth Sciences
Dartmouth College
Hanover, NH 03755 USA
DFO Contributions to the National Drought
Monitor
1) Validation of “Hydrologic Drought”, using MODIS
and ASTER
2) Documentation/Quantification of surface water
impact of Drought
3) Testing methods for long-term incorporation of
NASA satellite-derived surface water information
into the Drought Monitor
Example: ASTER Drought Map Series
Oklahoma/Texas Border
Period of Extreme Drought, July 18, 2006 to October 31, 2006
Stream gaging and soil moisture measurement or modeling provide information
concerning two aspects of hydrologic drought.
Meanwhile, NASA orbital remote sensing is well-posed to provide data
concerning drought-related changes in actual surface water supply: areal extent
and depth of rivers, reservoirs, and lakes and ponds. This example uses ASTER.
Map series shows surface water as detected by
ASTER on September 30, 2006 in pale blue
(during drought) on top of reference water from
May 3, 2004 in dark blue. Black lines are the
borders of the USGS 1:250,000-scale Hydrologic
Units of the United States. Rivers are shown in
pale grey (USGS ERF1_2 -- Enhanced River
Reach File 2.0). DCW roads and towns are also
shown. Map projection: UTM Zone 15 WGS 84.
Shaded relief background from SRTM.
The following are sample portions of first draft
maps, to be much modified!
ASTER-imaged
reservoir area
reductions north of
Sulphur Springs.
Many smaller water
bodies are shown as
absent; this result is
not yet validated.
ASTER-imaged reservoir area reductions west of
Winnsboro
ASTER-imaged Red River area
reductions
Shrinkage of small
stock ponds southwest
of Sulphur Springs.
Other dry ponds (dark
blue) not yet validated.
Initial Work Strategy, First DFO project Year:
1. Use ASTER change detection, water classification, and vectorization technologies to
measure at 10 m spatial resolution changes in water surface area for USDM hydrologic
drought-affected areas.
2. Use simultaneous MODIS 250 m band data in same regions and times to determine
MODIS-based signal of same changes.
3. Use MODIS to track evolution in time of surface water impact of drought for same
regions and same USDM drought event. Produce time series of surface water change.
4. Use ASTER-based water depth algorithms to measure water depth changes, to
accompany data on surface water areal extent, and with emphasis on small reservoirs.