Evaluating the Integration of a Virtual ET Sensor into AnnGNPS Model

1. Evaluating the Integration of a Virtual ET Sensor into AnnGNPS Model Dath Mita Lance Yarbrough Henrique Momm [The University of Mississippi] Rapid Prototyping Capability Project Collaborators Ronald Bingner (Ron) [USDA-ARS National Sedimentation Lab] Robert Ryan [SSAI-John C. Stennis Space Center]

2. Objectives • To provide a quantitative evaluation of the relationship between the potential evapotranspiration [ETP], Vegetation Index VI [MODIS data], and Land Surface Temperature LST [TRMM data] • To develop and evaluate a Virtual ET Sensor [VETS] model for estimating ETP using VI and LST data • To evaluate the possibility of applying VETS model ETP estimates in AnnAGNPS 1

3. AnnAGNPS [Annualized Agricultural Nonpoint Source Pollution Model] • AnnAGNPS is a distributed, continuous simulation watershed-scale program [developed by USDA] • Simulates point and nonpoint source [daily] quantities of: • surface water, • sediment, • nutrients, and • pesticides • The model output is expressed on an event basis for selected stream reaches and as source accounting [contribution to outlet] • The model can be used to evaluate Best Management Practices [BMPs]. 2

4. AnnAGNPS: Key Processes • Climate – Climate data are generated using GEM and Complete Climate • Hydrology – Daily soil moisture balance • Runoff – SCS curve number • Subsurface flow – lateral subsurface flow using Darcy’s equation or tile drain flow • Rill and sheet erosion – RUSLE • Sediment delivery – HUSLE • Chemical routing – dissolved or adsorbed by mass balance approach • Potential evapotranspiration [ET]– Penman equation 3

5. Project Overview • Current AnnAGNPS ET input process: • ETactual is derived as a function of ETpotential and Soil moisture content • ETpotential is based on PENMAN equation • Long process requiring several climate data inputs [wind, temperature, precip etc] • Limited ground weather stations limited and generalized watershed ET estimates • We propose to estimate ETpotential using a Virtual ET Sensor [VETS] based on input data from MODIS and TRMM satellites 4

6. Project Overview(cont..) • Decision Support System enhancement through • Replacement of PENMAN equation process with VETS model • Providing alternative method for derivation of ETpotential • Tasks: • Developing the VETS model • Initial validation of the VETS model using MOD16 [ET] and field data • Investigate application of VETS ET estimates in AnnAGNPS • Investigate application of VIIRS [simulated] data in AnnAGNPS • AnnAGNPS performance evaluation 5

7. STUDY AREA Lower Mississippi, Yazoo River Basin Yalobusha Watershed Rationale: -long history of hydrologic work -extensive infrastructure -long history of hydrologic data -NSL past & ongoing projects 6

8. VETS: Concept Weather historical data Vegetation Index Grid Land Surface Temperature Grid 7

9. Yalobusha Watershed [08030205] Simulation period Weather Station J F M A M J J A S O N D Project Summary: validation MOD16 AnnAGNPS MOD16 MODIS VI GRID Simulations Data: IR + R bands MODIS 1 Simulated VIIRS VI GRID MODIS daily PET GRID Virtual ET Sensor: Regression model Data Land Surface Temp LST GRID 2 VIIRS daily PET GRID Outputs TRIMM 3 • Peak Runoff est. • Sediment yield • Nutrient load Penman ET data Analysis & Evaluation Final Report 8

10. Project Schedule & Status

11. Thanks