Model Design

The primary component of the PT-JPL model is the Image() class. The Image class can be used to compute a single ET image from a single input image. The Image class should generally be instantiated from an Earth Engine Landsat image using the collection specific methods listed below. ET image collections can be built by computing ET in a function that is mapped over a collection of input images. Please see the Example Notebooks for more details.

Input Collections

PT-JPL can currently be computed for Landsat Collection 2 Level 2 (SR/ST) images images from the following Earth Engine image collections:

• LANDSAT/LT05/C02/T1_L2

• LANDSAT/LE07/C02/T1_L2

• LANDSAT/LC08/C02/T1_L2

• LANDSAT/LC09/C02/T1_L2

import openet.ptjpl as ptjpl

landsat_img = ee.Image('LANDSAT/LC08/C02/T1_L2/LC08_044033_20170716')
et_actual = ptjpl.Image.from_landsat_c2_sr(landsat_img).et

Example Notebooks

Meteorology

The GEE NLDAS hourly image collection is the default meteorology source for the hourly air temperature, vapor pressure, windspeed, and incoming short and longwave solar radiation.

Ancillary Datasets

Installation

The OpenET PT-JPL python module can be installed via pip:

pip install openet-ptjpl

Dependencies

• earthengine-api

• openet-core

OpenET Namespace Package

Each OpenET model is stored in the “openet” folder (namespace). The model can then be imported as a “dot” submodule of the main openet module.

import openet.ptjpl as model

Development and Testing

Please see the CONTRIBUTING.rst.

References