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Description
The Vegetation Drought Response Index (VegDRI) is a weekly geospatial model that depicts drought stress on vegetation within the conterminous United States. The development of the VegDRI drought-monitoring tool was a collaborative effort by scientists at the USGS EROS Center, the National Drought Mitigation Center (NDMC) at the University of Nebraska, and the High Plains Regional Climate Center (HPRCC).
VegDRI methodology integrates remote sensing data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the Terra platform with climate and biophysical data to create a seamless product with a 1 km spatial resolution.
The satellite components related to general vegetation conditions are Percent Annual Seasonal Greenness (PASG) and Start of Season Anomaly (SOSA) data. PASG is calculated weekly from eMODIS Normalized Difference Vegetation Index (NDVI) composites.
The climate-based drought data include the Palmer Drought Severity Index (PDSI) and weekly Standardized Precipitation Index (SPI) data from the HPRCC. Climate data identify areas that are experiencing dryness to help distinguish vegetation stress due to drought.
The biophysical characteristics of the environment are derived from land use/land cover, soil available water capacity, ecological setting, irrigation status, and elevation data. Environmental stressors such as land use change, soil conditions, pest infestations, disease, hail, flooding, or fire can also influence vegetation conditions.
This integrated approach considers climate and biophysical conditions to determine the cause of vegetation stress. This information is incorporated into the calculation of VegDRI to create an easy to interpret, color-coded map of drought stress on vegetation. Drought-monitoring maps are produced every week using the latest information and are usually posted each Monday by 10:30 a.m. CT.
Spatial extent: Conterminous United States Spatial resolution: 1000m Temporal resolution: Weekly Time span: 2009-04-22 to present Update frequency: Weekly on Monday by 10:30 a.m. CT
Variables
VegDRI (‘vegdri’)
Units: Unitless
Offset: -128 (see sample script)
Scale factor: 0.0625 (see sample script)
Values provided as 8-bit integers that can be scaled to range consistent with Palmer Drought Severity Index
Water (‘water’)
Units: Unitless
Scale factor: 1.0
Binary mask of water
Out-of-Season (‘out_of_season’)
Units: Unitless
Scale factor: 1.0
Binary mask of out-of-season (see documentation for more information)
Citation
Brown, J. F., Wardlow, B. D., Tadesse, T., Hayes, M. J., & Reed, B. C. (2008). The Vegetation Drought Response Index (VegDRI): A New Integrated Approach for Monitoring Drought Stress in Vegetation. GIScience & Remote Sensing, 45(1), 16–46. https://doi.org/10.2747/1548-1603.45.1.16
// Import VegDRIvarvegdri_ic=ee.ImageCollection('projects/climate-engine-pro/assets/ce-veg-dri')varvegdri_i=vegdri_ic.first()print(vegdri_i)// Link to methods webpage: https://www.usgs.gov/special-topics/monitoring-vegetation-drought-stress/science/methods-vegdri// Link to EROS page: https://www.usgs.gov/centers/eros/science/usgs-eros-archive-vegetation-monitoring-vegetation-drought-response-index// VegDRI data are stored as 8-bit integer data and can be scaled into the values below// Drought categories from EROS page// Category Bitmap PDSI vals// Extreme drought: 001-064 -7.9375 - -4.0000// Severe drought: 065-080 -3.9375 - -3.0000// Moderate drought: 081-096 -2.9375 - -2.0000// Abnormally dry: 097-112 -1.9375 - -1.0000// Near normal: 113-160 -0.9375 - 2.0000// Abnormally wet: 161-176 2.0625 - 3.0000// Moderately wet: 177-192 3.0625 - 4.0000// Extremely wet: 193-255 4.0625 - 7.7500// Water: 253// Out of season: 254// Other landcover: 255// Function to apply stretch to make consistent with values abovefunctionscale_vegdri(img){// Select vegdri band and scale to PDSI range.varvegdri_scale=img.select('vegdri').subtract(128)// convert to signed 8-bit integer.divide(16)// scale to PDSI range.rename('vegdri_scale')// rename imagereturnimg.addBands(vegdri_scale)}vegdri_ic=vegdri_ic.map(scale_vegdri)print(vegdri_ic)// VegDRI color palettevarvegdri_palette=["#720206","#cb3121","#e36b09","#fee301","#ffffff","#ffffff","#ffffff","#88f9c7","#53c285","#2b8032"]// Select individual image and apply to mapvarvegdri_i=vegdri_ic.first()Map.addLayer(vegdri_i.select('vegdri_scale'),{min: -5,max: 5,palette: vegdri_palette},'VegDRI')Map.addLayer(vegdri_i.select('out_of_season'),{min:254,max:254,palette: ['878787']},'VegDRI Out-of-Season')Map.addLayer(vegdri_i.select('water'),{min:253,max:253,palette: ['0000FF']},'Water')
Enter license information
USGS-authored or produced data and information are considered to be in the U.S. Public Domain.
Keywords
drought, climate, remote sensing, modis, pdsi, conus, united states
Code of Conduct
I agree to follow this project's Code of Conduct
The text was updated successfully, but these errors were encountered:
Contact Details
Contact the Climate Engine team at climateengine@gmail.com
Dataset description
Description
The Vegetation Drought Response Index (VegDRI) is a weekly geospatial model that depicts drought stress on vegetation within the conterminous United States. The development of the VegDRI drought-monitoring tool was a collaborative effort by scientists at the USGS EROS Center, the National Drought Mitigation Center (NDMC) at the University of Nebraska, and the High Plains Regional Climate Center (HPRCC).
VegDRI methodology integrates remote sensing data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on the Terra platform with climate and biophysical data to create a seamless product with a 1 km spatial resolution.
The satellite components related to general vegetation conditions are Percent Annual Seasonal Greenness (PASG) and Start of Season Anomaly (SOSA) data. PASG is calculated weekly from eMODIS Normalized Difference Vegetation Index (NDVI) composites.
The climate-based drought data include the Palmer Drought Severity Index (PDSI) and weekly Standardized Precipitation Index (SPI) data from the HPRCC. Climate data identify areas that are experiencing dryness to help distinguish vegetation stress due to drought.
The biophysical characteristics of the environment are derived from land use/land cover, soil available water capacity, ecological setting, irrigation status, and elevation data. Environmental stressors such as land use change, soil conditions, pest infestations, disease, hail, flooding, or fire can also influence vegetation conditions.
This integrated approach considers climate and biophysical conditions to determine the cause of vegetation stress. This information is incorporated into the calculation of VegDRI to create an easy to interpret, color-coded map of drought stress on vegetation. Drought-monitoring maps are produced every week using the latest information and are usually posted each Monday by 10:30 a.m. CT.
Spatial extent: Conterminous United States
Spatial resolution: 1000m
Temporal resolution: Weekly
Time span: 2009-04-22 to present
Update frequency: Weekly on Monday by 10:30 a.m. CT
Variables
VegDRI (‘vegdri’)
Water (‘water’)
Out-of-Season (‘out_of_season’)
External links
https://vegdri.unl.edu/Home.aspx
https://www.usgs.gov/centers/eros/science/usgs-eros-archive-vegetation-monitoring-vegetation-drought-response-index
Citation
Brown, J. F., Wardlow, B. D., Tadesse, T., Hayes, M. J., & Reed, B. C. (2008). The Vegetation Drought Response Index (VegDRI): A New Integrated Approach for Monitoring Drought Stress in Vegetation. GIScience & Remote Sensing, 45(1), 16–46. https://doi.org/10.2747/1548-1603.45.1.16
Link to Documentation
https://support.climateengine.org/article/141-vegdri
Earth Engine Snippet if dataset already in GEE
Enter license information
USGS-authored or produced data and information are considered to be in the U.S. Public Domain.
Keywords
drought, climate, remote sensing, modis, pdsi, conus, united states
Code of Conduct
The text was updated successfully, but these errors were encountered: