DROUGHT MONITORING DROUGHT MONITORING THROUGH THE USE OF THROUGH THE USE OF

MODIS SATELLITEMODIS SATELLITE

Amy Anderson, Curt Johnson, Dave Prevedel, & Russ Reading

OBJECTIVEOBJECTIVE► Create a tool that could Create a tool that could

determine vegetation conditions determine vegetation conditions on rangeland within the on rangeland within the Intermountain Region.Intermountain Region.

► Demonstrate Demonstrate the potential through the use of satellite data and remote sensing applications in assessing significant changes in land cover.

Save time & moneySave time & money

AccessibilityAccessibility

Limited personnelLimited personnel

MODIS Image of Utah, So. Idaho, Western Wyoming, MODIS Image of Utah, So. Idaho, Western Wyoming,

and Nevada. (U.S. Forest Service, 2002)and Nevada. (U.S. Forest Service, 2002)

► A tool A tool was developed using MODIS Satellite data as an indicator for:

DroughtDrought

Plant PhenologyPlant Phenology

Grazing UseGrazing Use

► Imagery was collected by the Moderation Resolution Imaging Spectroradiometer (MODIS). The MODIS instrument images the entire surface of the Earth every two days (daily in the northern latitudes), making observations in 36 co-registered spectral bands at moderate spatial resolutions of 250, 500, and 1,000 meters.

► Satellite data was compiled at the USDA Forest Service (USFS) Remote Sensing Applications Center in cooperation with NASA Goddard Space Flight Center and the University of Maryland.

► Biomass stress processing was completed by Region 4 USDA Forest Service.

http://modis.gsfc.nasa.gov/about/index.html

http://modis.gsfc.nasa.gov/about/index.html

Remote Sensing can detect:Remote Sensing can detect:

► Vegetation distribution and occurrence.Vegetation distribution and occurrence.

► The beginning and spread of damaged and stressed plants The beginning and spread of damaged and stressed plants before the damage is ever visible to the human eye.before the damage is ever visible to the human eye.

► How factors, such as moisture, latitude, altitude, length of the How factors, such as moisture, latitude, altitude, length of the growing season, solar radiation, temperature regimes, soil growing season, solar radiation, temperature regimes, soil type and drainage conditions, topographic aspect and slope, type and drainage conditions, topographic aspect and slope, prevailing winds, salt spray, and air pollutants influence the prevailing winds, salt spray, and air pollutants influence the environment.environment.

► Factors that influence the leaf optical properties are the Factors that influence the leaf optical properties are the internal or external structure, age, water status, mineral internal or external structure, age, water status, mineral stress, and the health of the leaf. stress, and the health of the leaf.

Reflectance is the same, regardless of the species.Reflectance is the same, regardless of the species.

► What may differ is the typical spectral response What may differ is the typical spectral response characteristics recorded for the three main optical spectral characteristics recorded for the three main optical spectral domains: leaf pigments, cell structure, and water contentdomains: leaf pigments, cell structure, and water content

► Bands used were 250 meter resolution.

► To identify the areas of biomass stress, MODIS band 1 (visible red) and band 2 (infra red) were used in the equation red ** 2 / infra red.

► Monitoring makes use of a Biomass Stress Indices algorithmMonitoring makes use of a Biomass Stress Indices algorithm, which are an indicator of the loss of biomass.

Resulting stress indices are a product of the amount of chlorophyll and Resulting stress indices are a product of the amount of chlorophyll and green growing material in plants.green growing material in plants.

Subsequent comparison of products over time should yield a Subsequent comparison of products over time should yield a representation of total growing plant biomass.  representation of total growing plant biomass. 

Any reduction of biomass over time may be attributed to a combination of Any reduction of biomass over time may be attributed to a combination of factors such as plant phenology (growth stages), plant moisture content, factors such as plant phenology (growth stages), plant moisture content, and removal by livestock grazing.and removal by livestock grazing.

METHODOLOGYMETHODOLOGY

► InIndicate areas that may need to be monitored and have on-the-ground inspections during the grazing season.

► Use as an administrative tool.

► Does not replace field work, but used as a means of selecting Does not replace field work, but used as a means of selecting priority areas to visit.priority areas to visit.

► Used to build base lines from multi-year data.Used to build base lines from multi-year data.

The data should be used as an indicator and not a direct The data should be used as an indicator and not a direct measurement.measurement.

Closer field inspection will be needed to evaluate specific areas.Closer field inspection will be needed to evaluate specific areas.

http://www.fs.fed.us/r4/resources/drought_monitoring/index.shtml

► Data is retrievable by National Forest and date.

► Overlain with grazing allotment boundaries.

► Previous years’ images available for comparison.

► Provides a means of timely assessment of rangeland monitoring (vegetation stress).

Forest ServiceForest Service

Grazing PermitteesGrazing Permittees

► The The colors represent observed ground conditions.

► Note that Desert Areas have different indicators than Montane areas as observed.

BRIDGER – TETON NATIONAL BRIDGER – TETON NATIONAL FORESTFOREST

COMPARATIVE DATACOMPARATIVE DATABridger – Teton NFBridger – Teton NF

2002 2003

FISHLAKE NATIONAL FORESTFISHLAKE NATIONAL FOREST

COMPARATIVE DATACOMPARATIVE DATAFishlake NFFishlake NF

2002 2003

MANTI – LA SAL NATIONAL MANTI – LA SAL NATIONAL FORESTFOREST

COMPARATIVE DATACOMPARATIVE DATAManti – La Sal NFManti – La Sal NF

2002 2003

ADVANTAGESADVANTAGES► Large areas can be monitored quickly and repetitively.Large areas can be monitored quickly and repetitively.

Complement traditional rangeland management procedures.Complement traditional rangeland management procedures.

• Field based inventoriesField based inventories• Ground monitoring techniquesGround monitoring techniques

► Target areas for field inspections can be quickly identified.Target areas for field inspections can be quickly identified.

Subsequent action undertaken in a timely manner.Subsequent action undertaken in a timely manner.

► Eliminates the problems of surface access that often hamper Eliminates the problems of surface access that often hamper ground surveys.ground surveys.

► Images provide a perspective that is lacking for ground Images provide a perspective that is lacking for ground surveys.surveys.

……ADVANTAGES ContinuedADVANTAGES Continued

► Image interpretation is more timely.Image interpretation is more timely.

► Image interpretation has minimal costs and has proven Image interpretation has minimal costs and has proven economical compared to the tangible benefits. economical compared to the tangible benefits.

Use public domain satellite data received by the Forest Service antenna.Use public domain satellite data received by the Forest Service antenna.

Process with Forest Service corporate software.Process with Forest Service corporate software.

► Images provide an objective, permanent data set for Images provide an objective, permanent data set for comparative analysis.comparative analysis.

► Active technology transfer without significant training or Active technology transfer without significant training or

costs to fulfill local needs.costs to fulfill local needs.

CONCLUSIONCONCLUSION

► Remote Sensing can accurately depict vegetation stress Remote Sensing can accurately depict vegetation stress on rangeland, proving to be an effective means of on rangeland, proving to be an effective means of management, in combination with other tools.management, in combination with other tools.