Spatial Analysis of Actual Evapotranspiration Estimates from the iUTAH Climate Station Network
Class
Article
Department
Civil and Environmental Engineering
Faculty Mentor
Scott B. Jones
Presentation Type
Oral Presentation
Abstract
Water demand is increasing whereas the supply is diminishing in many parts of the world. Estimating the loss of water through evapotranspiration (ET) processes in arid montane regions of the Intermountain West is important for efficient planning and management of water resources. In this study reference ET (ETr) was estimated using three different equations (i.e. FAO56-PM, ASCE Standardized -PM, Hargreaves-Samani; HS), which were compared with ET measured using the eddy covariance (EC) technique at the T.W. Daniel Experimental Forest (TWDEF) for the years 2010 and 2011. The HS method overestimated ETr by almost two times, while the FAO56-PM equation provided the closest estimates of ETr. The estimated ET values were compared as a function of elevation and found to be decreasing with increased elevation. The point estimates of ETr using the FAO56-PM equation were interpolated using the inverse distance weighting (IDW) method to provide temporal and spatial analysis of actual ET (ETa within iUTAH's (innovative Urban Transitions and Aridregion Hydro-sustainability) monitored watersheds. The ETa values were estimated as the proportion of ETr contributed by the fraction of vegetation derived from the Normalized Difference Vegetation Index (NDVI) computed at each pixel of Landsat images presented as a map for each watershed in May, June, July and August of 2014.
Start Date
4-9-2015 1:00 PM
Spatial Analysis of Actual Evapotranspiration Estimates from the iUTAH Climate Station Network
Water demand is increasing whereas the supply is diminishing in many parts of the world. Estimating the loss of water through evapotranspiration (ET) processes in arid montane regions of the Intermountain West is important for efficient planning and management of water resources. In this study reference ET (ETr) was estimated using three different equations (i.e. FAO56-PM, ASCE Standardized -PM, Hargreaves-Samani; HS), which were compared with ET measured using the eddy covariance (EC) technique at the T.W. Daniel Experimental Forest (TWDEF) for the years 2010 and 2011. The HS method overestimated ETr by almost two times, while the FAO56-PM equation provided the closest estimates of ETr. The estimated ET values were compared as a function of elevation and found to be decreasing with increased elevation. The point estimates of ETr using the FAO56-PM equation were interpolated using the inverse distance weighting (IDW) method to provide temporal and spatial analysis of actual ET (ETa within iUTAH's (innovative Urban Transitions and Aridregion Hydro-sustainability) monitored watersheds. The ETa values were estimated as the proportion of ETr contributed by the fraction of vegetation derived from the Normalized Difference Vegetation Index (NDVI) computed at each pixel of Landsat images presented as a map for each watershed in May, June, July and August of 2014.