1. An Introduction to VegDRI
Dr. Brian Wardlow
National Drought Mitigation Center (NDMC)
University of Nebraska-Lincoln
Bismarck, ND
October 22, 2007

2. What is VegDRI? VegDRI is a new drought index that combines
climate-based drought index data
satellite-based observations of vegetation conditions
biophysical information (land cover type and soils)
to produce a high spatial resolution (1-kilometer2) indicator
of drought-related vegetation stress that is updated
every 2 weeks throughout the growing season.

3. What is VegDRI?

4. VegDRI vs. U.S. Drought Monitor
VegDRI map for July 25, 2002
Drought Monitor map for July 23, 2002
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).

5. VegDRI Concept: Integration of Satellite, Climate, and Biophysical Data
Regression
Tree
Model
Climate
Data
Biophysical
Data
VegDRI Map

6. VegDRI Concept: Integration of Satellite, Climate, and Biophysical 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.
- Deficits (compared to average condition) might be caused by
drought, flooding, late greennup, land cover conversion, etc.

7. Coarser-resolution climate information provides evidence
VegDRI Concept: Integration of Satellite, Climate, and Biophysical Data
Satellite
Data
Climate
Data
Biophysical
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.

8. Biophysical data are incorporated into the VegDRI to
VegDRI Concept: Integration of Satellite, Climate, and Biophysical Data
Satellite
Data
Climate
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

9. VegDRI Modeling Approach
Model Inputs
Standardized Precipitation Index
Land Cover
Available Water Capacity
% Irrigated Farmland
Start of Season Anomaly
Regression Tree
Model
% Avg Seasonal Greenness
1-km2 VegDRI Map
Blue: climate input
Green: satellite-based observation of vegetation
Red: biophysical variable

10. VegDRI Expansion Schedule
for the U.S.
Operational in 2007
Spring 2008
Spring 2009
Expansion Schedule
(*) Note: All states will have a historical record
of VegDRI from 1989 to present.

11. VegDRI Website and Products
VegDRI products are available at the VegDRI page (debuted in May 2007) within the Monitoring section of the NDMC website.

12. 1. VegDRI Quick-View Maps (multiple spatial scales)
Regional-level
State-level
Sub-state
level

13. 1. VegDRI Quick-View Maps (cont). (land cover type)
Complete view
Cropland view
Rangeland view

14. 2. VegDRI Area Statistics (% area) (currently available at state-level only)
Wyoming – June 4, 2007
Entire state
Cropland

15. 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)

16. 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.

17. 5. Trendlines
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.

18. Additional VegDRI Project Activities
Complete time series of VegDRI maps (1989 – present)

19. Additional VegDRI Project Activities
Complete a time series of VegDRI map (1989 – present)
Weekly VegDRI map production

20. Additional VegDRI Project Activities
Complete time series of VegDRI map (1989 – present)
Weekly VegDRI maps
Evaluation of VegDRI’s 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)

21. Additional VegDRI Project Activities
Complete time series of VegDRI map (1989 – present)
Weekly VegDRI maps
Evaluation of VegDRI’s 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)
Research to enhance the current VegDRI model

22. Additional VegDRI Project Activities
Complete time series of VegDRI map (1989 – present)
Weekly VegDRI maps
Evaluation of VegDRI’s 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)
Research to enhance the current VegDRI model
Higher spatial resolution VegDRI (500- or 250-meters)

23. 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.

24. 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

25. 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.

26. The User’s Perspective of VegDRI
- Initial impressions?
- Comments?
- Suggestions?
- Questions?
If you would like further information or have questions regarding VegDRI, please contact:
Brian Wardlow