An Introduction to VegDRI

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An Introduction to VegDRI Dr. Brian
Wardlow National Drought Mitigation Center
(NDMC) University of Nebraska-Lincoln San
Angelo, TX April 24, 2008
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What is VegDRI?
VegDRI is a new hybrid drought index that
integrates - satellite-based observations of
vegetation conditions - climate-based drought
index data - biophysical
characteristics of the environment to
produce maps of drought-related vegetation stress
that have high spatial resolution (1-km)
and are regularly updated (currently at
2-week interval) throughout the growing
season.
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What is VegDRI?
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VegDRI vs. U.S. Drought Monitor
US Drought Monitor (USDM)
VegDRI
July 10, 2006
July 11, 2006
Goal of VegDRI Map and monitor more localized
patterns of drought-related vegetation stress
than commonly used drought indicators such as the
U.S. Drought Monitor (USDM).
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VegDRI Modeling Approach
1. Historical Database Development
Satellite Data
Data Input Variables
2. Model Development
3. Map Generation
1) Percent Annual Seasonal Greenness (PASG) 2)
Start of Season Anomaly (SOSA)
Climate Data
1) Palmer Drought Severity Index
(PDSI) 2) Standardized Precipitation
Index (SPI)
Biophysical Data
1-km2 VegDRI Map

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

() Models developed from a 17-year historical
record (1989 2005) of bi-weekly climate
and satellite observations at 1,600 weather
station locations. Biophysical variables
are static over time.
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VegDRI Expansion Schedule

• Information currently
• available for Texas
• - 2006 2007
• growing seasons
• Planned retrospective
• production of VegDRI
• maps dating from the 1989
• to the current growing
• season.

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VegDRI Website and Products
VegDRI products are available at the VegDRI page
within the Monitoring section of the NDMC
website.
http//www.drought.unl.edu/vegdri/VegDRI_Main.htm
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1. VegDRI Quick-View Maps(multiple spatial
scales)
Regional-level
State-level
Sub-state level
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1. VegDRI Quick-View Maps (cont).(land cover
type)
Complete view
Rangeland view
Cropland view
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2. VegDRI Area Statistics ( area)(currently
available at state-level only)

• Summarize the area of each VegDRI class for
  current map and
• all prior dates in the growing season.
• Specific tables available for rangeland and
  cropland.
• Tables are currently available only at state
  level.

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3. Change Maps

• 3 Types
• Prior period
• ex. - Sep 4, 2007 vs. Sep 10, 2007
• 2) Same period from the prior year
• or a specific year in past
• ( currently not available)
• ex. Sep 24, 2007 vs. Sep 24, 2006
• Historical average ( currently not available)
• ex. Sep 24, 2007 vs. average for Sep
  24 (1989
• through 2006)

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4. Animations
Goal Visualize spatial and temporal changes in
drought patterns across a specific year or
multiple years for a state or sub-state region.
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5. Trendlines (in development)
Plots the average VegDRI values over the growing
season for a specific geographic area (e.g.,
county) and land cover type (e.g., cropland and
rangeland). Comparisons of VegDRI could be made
between specific years and/or the long-term
average condition.
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6. Dynamic Map Viewer (in development)

• Zoom in pan across VegDRI maps
• Overlay multiple layers of other
• information
• - county boundaries, rivers, roads,
  and
• other boundaries (resource
  districts,
• section lines)
• - historical climate maps
• - land cover maps
• - U.S. Drought Monitor maps

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6. Dynamic Map Viewer (in development)
Zoom in to Texas
Overlay county boundaries
View a VegDRI map for a specific date(s).
The user customizes the view of the map for
their specific needs and interests.
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6. Dynamic Map Viewer (in development)
Capability to visualize information at the local
level for a county or multiple counties.
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6. Dynamic Map Viewer (in development)
View VegDRI maps in combination with other types
of maps. Examples -
climate-based drought indices (SPI and PDSI
- U.S. Drought Monitor
- land use land cover type
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Additional VegDRI Project Activities

• Complete a time series of VegDRI maps (1989
  present)

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Additional VegDRI Project Activities

• Complete a time series of VegDRI maps (1989
  present)
• Weekly VegDRI maps

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Additional VegDRI Project Activities

• Complete a time series of VegDRI maps (1989
  present)
• Weekly VegDRI maps
• Higher spatial resolution VegDRI (500- or
  250-meters)

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Additional VegDRI Project Activities

• Complete a time series of VegDRI maps (1989
  present)
• Weekly VegDRI maps
• Higher spatial resolution VegDRI (500- or
  250-meters)
• Evaluation of VegDRIs accuracy
• feedback from ag. producers and climate experts
• comparison to crop yield data and soil moisture
  observations
• comparison to other drought monitoring info.
  (U.S. Drought Monitor)

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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data
Biophysical Data

• Biophysical data are incorporated into the
  VegDRI to
• account for the different
  climate-vegetation response
• relationships that can occur for different
• - land cover types
• - soil types
• - land use practices (irrigated
  cropland)
• - ecosystem types

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• Possible Uses of VegDRI Information
• by Ranchers
• Justify sub-county declarations for the
  release of CRP
• lands for emergency grazing for parts of
  counties that
• might be severely impacted by drought.

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• Possible Uses of VegDRI Information
• by Ranchers
• Justify sub-county declarations for the
  release of CRP
• lands for emergency grazing for parts of
  counties that
• might be severely impacted by drought.
• Gauge rangeland and haying conditions in other
  states to
• determine locations to move cattle for
  grazing and
• purchase hay and other feed

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• Possible Uses of VegDRI Information
• by Ranchers
• Justify sub-county declarations for the
  release of CRP
• lands for emergency grazing for parts of
  counties that
• might be severely impacted by drought.
• Gauge rangeland and haying conditions in other
  states to
• determine locations to move cattle for
  grazing and
• purchase hay and other feed.
• Guide to assist new ranchers better manage
  their grazing
• lands and become better land stewards
  during drought
• events.

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An Introduction to VegDRI Dr. Brian
Wardlow National Drought Mitigation Center
(NDMC) University of Nebraska-Lincoln San
Angelo, TX April 24, 2008
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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data
Satellite Data

• Satellite-based observations are used to
  highlight areas
• with anomalous vegetation conditions.
• () Provides continuous spatial coverage
  of general vegetation conditions
• at high spatial resolution
  (1-km2) over large geographic areas.
• - A considerable number of vegetation
  condition products derived from
• satellite-based vegetation
  index (VI) data.

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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data
Satellite Data

• Satellite-based observations are used to
  highlight areas
• with anomalous vegetation conditions.
• (-) Deficits (compared to average
  condition) might be caused by
• drought, flooding, late
  greennup, land cover conversion, etc.

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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data
Climate Data

• Coarser-resolution climate information provides
  evidence
• of the level of dryness for the
  interpretation of the satellite data
• anomalies to identify vegetation impacted by
  drought.
• - Drought areas identified by below
  average vegetation conditions
• recorded in the satellite data and
  drier than normal conditions
• in the climate data.

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VegDRI ConceptIntegration of Satellite,
Climate, and Biophysical Data

• Satellite Data
• spatially detailed patterns
• of vegetation and their
• general condition

• Climate Data
• broad-scale spatial
• patterns of dryness

Biophysical Data - land use/land cover type
- soil characteristics - elevation -
ecological setting
VegDRI Map