The Vegetation Drought Response Index VegDRI

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The Vegetation Drought Response Index (VegDRI) An
Update on Progress and Future Activities
Brian Wardlow1, Jesslyn Brown2, Tsegaye Tadesse1,
and Yingxin Gu2 1National Drought Mitigation
Center (NDMC) 2USGS Center for EROS U.S. Drought
Monitor Forum Portland, OR October 10-11, 2007
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What is VegDRI?
VegDRI is a new drought index that combines -
climate-based drought index data -
satellite-based observations of vegetation
conditions - biophysical information (e.g.,
land cover type and soils) to produce maps of
drought-related vegetation stress that have high
spatial resolution (1-km2) and can be updated in
near real-time (currently at a 2-week interval).
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What is VegDRI?
VegDRI is a new drought index that combines -
climate-based drought index data -
satellite-based observations of vegetation
conditions - biophysical information (e.g.,
land cover type and soils) to produce maps of
drought-related vegetation stress that have high
spatial resolution (1-km2) and can be updated in
near real-time (currently at a 2-week interval).
Goal A tool that has national-level monitoring
capabilities and can provide local-scale drought
information (i.e., county-level).
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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data
1) Percent Annual Seasonal Greenness (PASG) 2)
Start of Season Anomaly (SOSA)
1) self-calibrated Palmer Drought Severity Index
(PDSI) 2) Standardized Precipitation Index (SPI)

• 1) land use/land cover type
• soil available water
• capacity (STATSGO)
• ecoregion type
• irrigation status

() Models developed from a 17-year historical
record (1989 2005) of bi-weekly climate and
satellite observations .
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Expansion Schedule for Operational VegDRI
Production
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Operational VegDRI Product Development

• Drought Monitoring viewer hosted by the USGS

• Zoom and pan options
• Overlay capabilities
• Multiple layers of
• information

http//gisdata.usgs.net/website/Drought_Monitoring
/viewer.php
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Operational VegDRI Product Development
2. VegDRI webpage in Monitoring section of the
NDMC website - debuted in May 2007
Goal Provide quick view maps and other
graphical information.
http//www.drought.unl.edu/vegdri/VegDRI_Main.htm
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VegDRI Quick-View Maps(multiple spatial scales)
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VegDRI Quick-View Maps(land cover type)
Complete
Rangeland
Cropland
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VegDRI Area Statistics ( area)(currently
available at state-level only)
Wyoming June 4, 2007
Entire state
Rangeland
Cropland
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Change Maps

• 3 Types
• Prior period
• ex. - June 4, 2007 vs. May 21, 2007
• 2) Same period from the prior year
• or a specific year in past
• ( currently not available)
• ex. June 4, 2007 vs. June 4, 2006
• Historical average ( currently not available)
• ex. June 4, 2007 vs. average for June
  4 (1989 through 2006)

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Proposed VegDRI Products

• Time-series animations
• Trend line graphs track VegDRIs response
  across the year by major land cover type (e.g.,
  cropland and rangeland) for a geographic area
  (e.g., county, watershed, or NRD)
• Ranking or percentile maps for each period
• - Produced when a historical time series of
  VegDRI maps
• is produced from 1989 present.
• 4. Weekly updates of VegDRI maps

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Evaluation of VegDRI A Multi-Source Convergence
of Evidence Approach

• Feedback from 81 evaluators across the 15-state
  region.
• Composition
• 19 climate experts (state climatologists
  USDM authors)
• 42 agricultural specialists and other
  experts (extension govt agencies)
• 20 agricultural producers
• User workshops 3 per year nationally
• 2006 Illinois, Oklahoma, and New Mexico
• 2007 North Dakota, Texas, and Wyoming
• 2008 western U.S. (states TBD)
• 2009 eastern U.S. (states TBD)

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Evaluation of VegDRI A Multi-Source Convergence
of Evidence Approach

• Feedback from 81 evaluators across the 15-state
  region.
• Comparisons with other drought index maps (e.g.,
  USDM).

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Evaluation of VegDRI A Multi-Source Convergence
of Evidence Approach

• Feedback from 81 evaluators across the 15-state
  region.
• Comparisons with other drought index maps (e.g.,
  USDM).
• Comparisons with ground truth data.
• USDA county crop yield data
• Soil moisture data (state MESONETS)
• Biophysical vegetation data (USDA ARS and LTERs)
• - biomass, leaf area index,
  and net primary productivity

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VegDRI Research Activities

• Test additional variables in the VegDRI models
• - land surface temperature
• - DEM products (elevation, slope,
  and aspect)
• - higher resolution SSURGO soils
  data
• - irrigated lands map derived from
  remotely sensed data
• Investigate the use of satellite-based VI
  observations from
• instruments similar to the AVHRR
  (Advanced Very High
• Resolution Radiometer)
• - MODIS (Moderate Resolution
  Imaging Spectroradiometer)
• - VIIRS (Visible/Infrared
  Imager/Radiometer Suite)
• 3. Explore the development of a 250-m VegDRI
  using MODIS
• data.

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Additional Remote Sensing-Related Projects at
the NDMC

• Vegetation Outlook (VegOut) provides 1-km2
  outlook maps
• of future vegetation conditions (2-, 4-,
  and 6-week time steps)
• USGS EROS / NDMC Collaboration
• National-level irrigation mapping (250-m)
• Normalized Difference Water Index (NDWI)
  (500-m)
• ET estimation from land surface temperature
  data (1-km)
• CALMIT / NDMC Collaboration
• estimation of biophysical characteristics of
  vegetation (250-m)
• - LAI, green biomass, chlorophyll content,
  and FPAR
• development for spectral/thermal-based
  indicators for
• drought monitoring (500-m)