Remote Sensing in Drought Monitoring Myths and Realities

Remote Sensing in Drought Monitoring: Myths and Realities Jesslyn F. Brown SAIC, contractor for USGS at the Center for Earth Resources Observation and Science (EROS) 5 th U. S. Drought Monitor Forum, Oct. 10 -11, 2007 U. S. Department of the Interior U. S. Geological Survey

Special Acknowledgements EROS NDMC § § § § Mike Budde Yingxin Gu Calli Jenkerson Ron Lietzow Susan Maxwell Shahriar Pervez Gail Schmidt Gabriel Senay Karin Callahan Eric Hunt Soren Scott Tsegaye Tadesse Brian Wardlow Funding provided by USGS, USDA R Management Agency, and NASA Drought Forum Portland, Oregon October 10 -11, 2007

Topics § Status of EROS research and products § Vegetation Drought Response Index (Veg. DRI) § e. MODIS § Irrigated area mapping (MODIS) § Normalized Difference Water Index (MODIS) § Simple Energy Balance/Evapotranspiration (MODIS) MODIS = Moderate Resolution Imaging Spectroradiometer Drought Forum Portland, Oregon October 10 -11, 2007

Topics § Bigger Picture—What is the current and future role of remote sensing in drought monitoring in the U. S. ? “Myths and Realities” Disclaimer: the views I express here are my own and in no way should they be construed as representing the official policies or opinions of either the US Geological Survey, the Department of the Interior, Executive Branch of the United States Government, any of the officials of these offices, of these entities in aggregate, nor of those of any other person, or organization. They are my opinions, mine alone, and I am responsible for them. Drought Forum Portland, Oregon October 10 -11, 2007

EROS Land Change System: Drought Monitoring Georegistration Compositing Surface Reflectance AVHRR Existing Intercalibration MODIS Satellite Data 2008 Stacking Smoothing Anomaly Detection Metrics Calculation (SOS, SG, PASG) Veg. DRI models Remote Sensing Data Services Subscribers get “Regular data over the Nation served quickly” Drought Forum User/Decision Portland, Oregon Support System October 10 -11, 2007

Current Year Veg. DRI Products July 30, 2007 Drought Forum Portland, Oregon October 10 -11, 2007

Veg. DRI Automation and Software Efficiencies § § § Programming: Veg. DRI system software Gained efficiencies: trimmed ~2 hours off of processing times from last year (still hampered by AVHRR composite processing issues) Server improvements: stability and disk Testing automated system based on historical AVHRR input In Spring 2008, will test system in near-real time based on AVHRR and MODIS satellite Drought Forum inputs Portland, Oregon October 10 -11, 2007

Input Data MODIS Vegetation Indices AVHRR NDVI Data Mining and Information Discovery Subsystem Searchives Mosaic Derive metrics Data rescaling Extract samples 1992 National Land Cover Database (NLCD) Reproject Calc dominant LC Subset Extract samples State Soil Geographic (STATSGO) Database Extract Attributes Calculate Variables Omernik EPA Level III Ecoregions % of Land in Farms in Irrigation (USDA) Standardized Precipitation Index (bi-weekly) Palmer Drought Severity Index (bi-weekly) Rasterize Reproject Subset Extract samples Modeling and Dissemination Subsystems CART analysis of input variables Iterate with sample analyses Data retrieval Reprojection Derive variable coefficients and weights Image Produce Text File Database of Model Variables Model Parameters And Rules Model Input Data Model Results Image Produce Text File Reports Maps Apply Model to Calculate Vegetation Drought Response Index (Veg. DRI) Calculate variables Polygon encoding Data retrieval Compile database Segment seasons Interpolate surface Extract samples U. S. Drought Monitor DSS Subset Reproject Rescale data Image Produce Text File Dynamic Inputs New input datasets Static Inputs Model Formulation and Implementation; Recurring Operations Dependent variable Drought Forum Portland, Oregon 10 -11, 2007 Processes. October to be automated or improved

Schedule for expansion Summer 2006 Spring 2007 Winter 2007 Summer 2008 Drought Forum Portland, Oregon October 10 -11, 2007

2007 Veg. DRI Map Access http: //gisdata. usgs. gov/website/Drought_Monitoring/viewer. php Quick. Views http: //www. drought. unl. edu/vegdri/Veg. DRI_Main. htm Dynamic Map Viewer Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

MODIS sensor shows spectral and spatial resolution improvements compared to the widely used AVHRR sensor The channels and the optical spectral sensitivities for MODIS, AVHRR, and LANDSAT Green Grass Dark Soil Dry Grass UV VISIBLE NEAR IR 1 NOAA AVHRR 1970 s> MODIS 2000> 3 4 1 LANDSAT ETM+ 1990 s> 1 2 3 SHORTWAVE INFRARED 2 2 4 5 6 5 7 7 Drought Forum Portland, Oregon October 10 -11, 2007

e. MODIS Concept Product Characteristics Expedited Instruments Aqua and Terra MODIS Extent Continental U. S. (CONUS) Spatial Resolutions 250, 500, and 1000 meters Product Latency Archive Persistence Composite Period Example e. MODIS product: Terra MODIS 1000 m NDVI CONUS composite for August 28, 2006 Historic Layers Projection/Format ~ 1 day after last input < 30 days after last input 90 days Indefinitely 7 -day, Rolling 7 -day, Interval NDVI, Surface Refl. Bands, Quality, Acq. Date Lambert Equal Area Azimuthal / Geo. TIFF Processing Flow Expedited L 1 B (NOAA NRT) Cloud Mask Processing (MODIS PGE 03) Historic L 1 B (NASA LAADS) Surface Refl. Processing (MODIS PGE 11) Ancillary Data Composite Processing (NDVI, CONUS) Long Term Archive and Web-enabled Access Drought Forum Portland, Oregon October 10 -11, 2007

Veg. DRI Model Improvements § Improve quality and resolution of irrigated agricultue Drought Forum Portland, Oregon October 10 -11, 2007

Veg. DRI Inputs: Original Irrigation Layer Census of Agriculture statistics + land cover mask Drought Forum Portland, Oregon October 10 -11, 2007

Prototype 2002 Irrigated Lands Map Drought Forum Portland, Oregon October 10 -11, 2007

Irrigated Agriculture Methodology MODIS Annual Peak NDVI County irrigated area statistics Land cover mask Drought Forum Portland, Oregon October 10 -11, 2007

MODIS 250 meter NDVI time-series Drought Forum Portland, Oregon October 10 -11, 2007

Satellite Derived Vegetation Indices § § NDVI related to energy absorbed by the vegetative canopy to fuel photosynthesis (integrated measure) NDWI responds to changes in the water content (absorption of SWIR radiation) and spongy mesophyll in vegetation canopies Drought Forum Portland, Oregon October 10 -11, 2007

NDWI: MODIS sensor shows spectral and spatial resolution improvements compared to the widely used AVHRR sensor The channels and the optical spectral sensitivities for MODIS, AVHRR, and LANDSAT Green Grass Dark Soil Dry Grass UV VISIBLE NEAR IR 1 NOAA AVHRR 1970 s> MODIS 2000> 3 4 1 LANDSAT ETM+ 1990 s> 1 2 3 SHORTWAVE INFRARED 2 2 4 5 6 5 7 7 Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

East Amarillo Fire Drought Forum Portland, Oregon October 10 -11, 2007

Soil moisture sites in the OK Mesonet Drought Forum Portland, Oregon October 10 -11, 2007

Simplified Energy Balance Approach to Monitor Actual Evapotranspiration Step 1: Use MODIS thermal data to develop ET fractions (comparable to the combination of crop coefficient Kc and soil stress Coefficient Ks) ETfrac = Thot – Tx ----Thot - Tcold Step 2: Produce actual ET estimates by multiplying the ET fractions by a global reference ET (ETo), produced at EROS ET = ETfrac * ETo Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

Drought Forum Portland, Oregon October 10 -11, 2007

Future Plans for the Simple Energy Balance Work § § § Collect feedback on 2006 products Continue to process central Great Plains data (2000 – 2006) for flash drought investigation Part of the U. S. Water Census? Drought Forum Portland, Oregon October 10 -11, 2007

Drought Monitoring at County and Subcounty Scales § § A major goal is to improve the detail of decision-making products This is stated in the 2004 Western Governors’ Association Report “A clear way to accomplish this is to incorporate gridded inputs at higher resolutions, that is remote sensing products. ” Drought Forum Portland, Oregon October 10 -11, 2007

Bigger Picture—What is the role of remote sensing in drought monitoring in the U. S. ? “Myths and Realities” § One goal is to improve the detail of decision-making products to sub-county § This is stated in the 2004 Western Governors’ Association Report “A clear way to accomplish this is to incorporate gridded inputs at higher resolutions, aka remote sensing. ” Drought Forum Portland, Oregon October 10 -11, 2007

Principal Drought Monitor Inputs USGS Streamflow CPC Daily Soil Model Palmer Drought Index USDA Soil Ratings 30 -day Precip. Satellite Veg Health Drought Forum Portland, Oregon October 10 -11, 2007

Principal Drought Monitor Inputs USGS Streamflow 30 -day Precip. CPC Daily Soil Model Palmer Drought Index USDA Soil Ratings Drought Forum Portland, Oregon October 10 -11, 2007

Remote Sensing in Drought Monitoring: Myths and Realities ? Are there barriers to using remote sensing products in the USDM? ? What are they and can they be eliminated or minimized? Drought Forum Portland, Oregon October 10 -11, 2007

Remote Sensing Myths and Realities Related to “period of record” Related to “product latency” or “production schedule” Related to “mismatch between the product design and the drought application” Drought Forum Portland, Oregon October 10 -11, 2007

“DRAFT” USDM Requirements for Remote Sensing Vegetation Input Data § § § § Consistent Reliable In anomalous vegetation signal, drought effects separated from non-drought Seasonality/phenology taken into account Familiar drought-like categorization Timely delivery (to USDM authors by Mon/Tues) Current information (latency not more than 48 hours—ideally within 24 hours) Drought Forum Portland, Oregon October 10 -11, 2007

Strengthen Partnerships <<<Improve communication on both sides>>> ** NIDIS Knowledge Assessment Workshop (probably next February) “Contributions of Satellite Remote Sensing to Drought Monitoring” § Planned workshop report: a compendium of current and upcoming national remote sensing products, their characteristics and uncertainties Drought Forum Portland, Oregon October 10 -11, 2007

The remote sensing community can: § § § Improve response to drought community requirements Document/provide improved explanations for products that are tailored to the users Increase direct involvement with the drought monitoring community by requesting feedback Drought Forum Portland, Oregon October 10 -11, 2007

The drought community can: § § § Increase feedback (especially constructive criticism) on products Test and evaluate products Facilitate understanding that, just like drought indices, there is no single remote sensing product that will track both shortterm and long-term drought signals Drought Forum Portland, Oregon October 10 -11, 2007

Jesslyn Brown 605. 594. 6003 jfbrown@usgs. gov Comments and Questions? Drought Forum Portland, Oregon October 10 -11, 2007