Location: Hydrology and Remote Sensing LaboratoryTitle: An intercomparison of evapotranspiration estimates derived using thermal-based satellite remote sensing for irrigation management in California vineyards
|Kustas, William - Bill|
|HIPPS, L.E. - Utah State University|
|ALSINA, M. - E & J Gallo Winery|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2017
Publication Date: 11/13/2017
Citation: Knipper, K., Kustas, W.P., Anderson, M.C., Alfieri, J.G., Prueger, J.H., Gao, F., McKee, L.G., Hipps, L.E., Alsina, M. 2018. An intercomparison of evapotranspiration estimates derived using thermal-based satellite remote sensing for irrigation management in California vineyards [abstract]. Pecora Abstracts. p. 29.
Technical Abstract: Irrigation in the central valley of California is essential for successful wine grape production, which represents nearly 1 million acres valued at approximately 6 billion dollars. With reductions in water availability and competing water use interests in much of California, there is a critical need in optimizing water management strategies to preserve water resources and maintain sustainable wine grape production. In the current study, we investigate the utility of satellite-derived maps of evapotranspiration (ET) based on remotely sensed land surface temperature (LST) imagery as a useful tool to determine crop water use and stress. Specifically, we evaluate a two-source (soil+substrate) remote sensing-based ET modeling approaches over two Pinot noir vineyard sites being monitored as part of the Grape Remote sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX). The Disaggregated Atmosphere Land EXchange Inverse (ALEXI/DisALEXI) modeling system provides ET estimates with both high spatial (30m) and temporal (daily timesteps) resolution by fusing LST data from multiple satellite platforms. Surface energy balance/ET and biophysical data collected from each vineyard between years 2013 and 2016 are used to evaluate model performance. Estimates of daily ET derived using ALEXI/DisALEXI agree reasonably well with ground-based flux estimates, with slight positive biases during the spring season and small negative biases reported during the growing season. In comparison, the Mapping Evapotranspiration with Internalized Calibration (METRIC) modeling approach adapted for vineyards indicates a positive bias throughout the period of investigation, which could result in over watering of the vineyards as well as not providing appropriate stress levels via deficit irrigation during certain stages of grape development used to improve grape quality. Evaluation of the ALEXI/DisALEXI daily ET product is expanding over other vine varieties and climates in California and we are exploring ways to use this information in supporting operational water management decisions in vineyards.