OpenET CONUS PT-JPL Monthly Evapotranspiration v2.0

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conus evapotranspiration gridmet-derived landsat-derived monthly openet water


Priestley-Taylor Jet Propulsion Laboratory (PT-JPL)

The core formulation of the PT-JPL model within the OpenET framework has not changed from the original formulation detailed in Fisher et al. (2008). However, enhancements and updates to model inputs and time integration for PT-JPL were made to take advantage of contemporary gridded weather datasets, provide consistency with other models, improve open water evaporation estimates, and account for advection over crop and wetland areas in semiarid and arid environments. These changes include the use of Landsat surface reflectance and thermal radiation for calculating net radiation, photosynthetically active radiation, plant canopy and moisture variables, and use of NLDAS, Spatial CIMIS, and gridMET weather data for estimating insolation and ASCE reference ET. Similar to the implementation of other OpenET models, estimation of daily and monthly time integrated ET is based on the fraction of ASCE reference ET. Open water evaporation is estimated following a surface energy balance approach of Abdelrady et al. (2016) that is specific for water bodies by accounting for water heat flux as opposed to soil heat flux.

Additional information


30 meters


Name Units Description
et mm

PT-JPL ET value

count count

Number of cloud free values

Terms of Use

Terms of Use



  • Fisher, J.B., Tu, K.P. and Baldocchi, D.D., 2008. Global estimates of the land–atmosphere water flux based on monthly AVHRR and ISLSCP-II data, validated at 16 FLUXNET sites. Remote Sensing of Environment, 112(3), pp.901-919. doi:10.1016/j.rse.2007.06.025

  • Abdelrady, A., Timmermans, J., Vekerdy, Z. and Salama, M., 2016. Surface energy balance of fresh and saline waters: AquaSEBS. Remote sensing, 8(7), p.583. doi:10.3390/rs8070583


Explore with Earth Engine

Code Editor (JavaScript)

var dataset = ee.ImageCollection('OpenET/PTJPL/CONUS/GRIDMET/MONTHLY/v2_0')
  .filterDate('2020-01-01', '2021-01-01');

// Compute the annual evapotranspiration (ET) as the sum of the monthly ET
// images for the year.
var et ='et').sum();

var visualization = {
  min: 0,
  max: 1400,
  palette: [
    '9e6212', 'ac7d1d', 'ba9829', 'c8b434', 'd6cf40', 'bed44b', '9fcb51',
    '80c256', '61b95c', '42b062', '45b677', '49bc8d', '4dc2a2', '51c8b8',
    '55cece', '4db4ba', '459aa7', '3d8094', '356681', '2d4c6e',

Map.setCenter(-100, 38, 5);

Map.addLayer(et, visualization, 'OpenET PT-JPL Annual ET');
Open in Code Editor