Evapotranspiration Measurement and Modeling Community

The Evapotranspiration Measurement and Modeling Community is an ASA Community within the Climatology and Modeling Section

Evapotranspiration (ET) is loosely defined as the sum of ground surface evaporation and plant transpiration. It is one of the major hydrologic processes regulating the water and energy balance of earth's biosphere, hydrosphere, and atmosphere. Specifically in production agriculture, ET represents a huge consumption of limited fresh water resources and plays a major role in achieving sustainable crop production and food security. Therefore, agronomists, ecologists, hydrologists, soil scientists and even atmospheric scientists require accurate evapotranspiration estimates/observations directly or indirectly in their studies. Not surprisingly, ET has become a tool for decision support system in solving various water resources and ecological problems.

Advances over the last few decades in instrumentation, data acquisition systems, remote data access, and the off-the-shelf availability of ET measurement tools have significantly enhanced our understanding of ET and its relation to microclimatic conditions. Numerous crop and hydrologic simulation models are now being used in tandem with in-situ experiments to evaluate the effects of soil types, climates, management, genotypes, etc. on crop yield. However, these models have large variation in the prediction of ET, both in methodology and results. Further, most of these models were calibrated and validated during their development in early 1990s. Therefore, efforts are underway by various groups of scientists to find solutions to this issue.

Better understanding and accurate measurement of dynamics of water, carbon and energy fluxes in agricultural biomes is important for predicting the future feedback on atmospheric CO2. The intricate linkages and simultaneously occurring nature of water, carbon and energy processes gives the leverage to monitor these under a single experimental setup using advances in Eddy covariance instrumentation and theory. Another frontier is satellite-based energy balance models for assessing spatial and temporal variability of crop coefficient (Kc) and ET. Remote sensing data from various ground, aerial, and satellite platforms are now increasingly used to derive ET data from surface temperature, reflectance, and vegetation indices. Advances in this new ET estimation technology will likely provide improved capability for routinely mapping ET, especially at the watershed or regional scale. Remote sensing can also be a viable tool for assessing the spatial distribution of ET for in-season irrigation management, water resource allocation, long-term estimates of water supply, demand and use, design and management of water resources infrastructure, and evaluation of the effect of land use and management changes on the water balance.

Although members of the Tri-societies constitute a larger portion of ET researchers and users group, until 2011 most of the new developments in measurements and modeling of ET were disseminated mainly through other earth sciences related professional societies such as American Geophysical Union and American Meteorological Society. Therefore, in 2011 the Remote Sensing of Evapotranspiration community was formed, which was renamed in 2012 to Evapotranspiration Measurement and Modeling (EMM) to reflect the broader scope of interests among its members. The EMM community functions under the Climatology and Modelling Section of the American Society of Agronomy (ASA) and it was formed to bring together a diverse group of agro-ecosystems modelers/scientists to a common platform where they can discuss and share research findings and ideas related to surface and ground water balance, crop water use, plant breeding, meteorology, and climate change issues from plant to regional scale. ET measurement over land surfaces across hydrological and agro-climatological regimes requires employment of relatively complex physical principles together with careful selection of measurement equipment and model parameterization. The EMM community has a strong membership base from all three societies and growing, reflecting the importance of ET in agronomy, soil and crop sciences.

The main focus of the EMM community is to report on advances in development and applications of ET measuring instruments/sensors such as lysimetry, neutron probes, Eddy covariance, Bowen ratio, scintillometer, sap flow, ET gauges, etc. as well as remote sensing-based techniques and direct modeling for estimating ET/crop water use at plot, field, landscape and regional scales. The EMM community also focuses on ET applications in water rights, interstate compacts, invasive species, agricultural and urban allocations, endangered species protection, drought and food insecurity, large-scale land-surface and climate models, water conservation projects, irrigation performance, environmental impact assessment due to groundwater extractions, hydrological modeling, crop modeling, assessing crop water productivity, and irrigation scheduling, to name a few.


Since its inception, the EMM community has sponsored symposiums and general sessions during the annual meetings of the Tri-societies which had garnered huge interest among presenting scientists and audience. The community has acquired financial support through the competitive program enhancements funds, which has enabled it to invite renowned scientists as guest speakers in its sessions. The EMM community organizes graduate student competitions every year and awards are given in both oral and poster categories to encourage and recognize student efforts.


We invite you to join this community and participate in the advancement of science in terms of ET measurement, modeling and applications. Your inputs are highly valued, please forward them to our leadership.  

View Evapotranspiration Measurement and Modeling Community Leadership Roster

View 2017 "Know Your Community" article

ASA 2017 Sessions Sponsored by this community

1. Symposium -- Evapotranspiration (ET) Under Pressure:  Measuring and Modeling ET Under Drought and Deficit Conditions

2. Evapotranspiration Measurement and Modeling Oral

3. Evapotranspiration Measurement and Modeling Poster


ASA 2016 Sessions Sponsored by this community 

1. Symposium - Partitioning of Evapotranspiration:  Instrumentation and Simulation

2. Evapotranspiraton Measurement and Modeling - Oral

3. Evapotranspiration Measurement and Modeling - Poster


Graduate Student Compeition Winners - 2016

1. Mallika Nocco - Oral
2. Seth Kutikoff - Poster


ASA 2014 Sessions Sponsored by this community

1. Symposium--Evapotranspiration in Crop and Hydrologic Models: Testing, Refinements and Cross-Comparisons: I

2. Evapotranspiration in Crop and Hydrologic Models: Testing, Refinements and Cross-Comparisons: II

3. General Evapotranspiration Measurement and Modeling: I 

4. General Evapotranspiration Measurement and Modeling: II


ASA 2013 Sessions Sponsored by this community

1. Symposium--Accuracy, Uncertainty, and Limitations of Evapotranspiration Quantification in Agriculture

2. Advances in Evapotranspiration Measurement and Modeling

3. Evapotranspiration Measurement and Modeling for Improved Water/Risk Management


ASA 2012 Sessions Sponsored by this community

1. Symposium--Evapotranspiration: Monitoring, Modeling and Mapping At Point, Field, and Regional Scales: I

2.  Evapotranspiration: Monitoring, Modeling and Mapping At Point, Field, and Regional Scales: II

3.  Evapotranspiration: Monitoring, Modeling and Mapping At Point, Field, and Regional Scales: III