Toward an Earth System Modeling Approach to Simulate Irrigation Effects

Land model improvements are enabling more realistic representations of the climate and hydrological consequences of crop irrigation.

Image courtesy of David Wiley via a Creative Commons license.
Crop irrigation impacts the use and supply of freshwater around the world, and scientists are working to understand how these impacts may change over regions and time, especially under the influence of climate change.

The Science

World agriculture consumes about 87% of global freshwater withdrawals, significantly altering the global water cycle. Understanding irrigation’s impact on land surface heat and moisture fluxes, surface and subsurface states, and their interactions with atmospheric processes is crucial for determining historical climate change and modeling future climate at local and regional scales. Researchers have evaluated the performance of the Community Land Model version 4 (CLM4) against observations from agricultural census data, improving the model’s simulations of hydrological changes resulting from irrigation practices.

The Impact

The study’s results suggest that calibrating CLM4 parameter values and accurately representing the spatial distribution and intensity of irrigated areas will improve CLM4-simulated irrigation amount and surface fluxes.


Previous sensitivity studies of irrigation impacts on land surface provide limited analysis of uncertainties from the input data and model irrigation schemes. A team of scientists led by Department of Energy (DOE) researchers at Pacific Northwest National Laboratory found that when inputting irrigation area fraction datasets from two widely used sources, CLM4 tended to produce unrealistically large temporal variations of irrigation demand for water resources at the regional scale over the conterminous United States. The research recommends a critical path forward to realistic assessments of irrigation impacts by developing CLM to include groundwater pumping and irrigation efficiency modules, and coupling CLM with streamflow routing and water management modules to account for all water supply sources.


Maoyi Huang
Pacific Northwest National Laboratory


This study was supported by the integrated Earth System Model (iESM) project funded by DOE’s Earth System Modeling program. The Platform for Regional Integrated Modeling and Analysis (PRIMA) initiative at DOE’s Pacific Northwest National Laboratory provided the model configuration and datasets used in the numerical experiments. Partial funding also was provided by the National Natural Science Foundation of China (41171031) and the National Basic Research Program of China (2012CB955403).


Leng, G., et al. “Modeling the effects of irrigation on land surface fluxes and states over the conterminous United States: Sensitivity to input data and model parameters.” J. Geophys. Res. Atmos. 118, 9789–9803 (2013). [DOI: 10.1002/jgrd.50792].

Related Links

Integrated Earth System Model (iESM) project

Platform for Regional Integrated Modeling and Analysis (PRIMA) initiative

Highlight Categories

Program: BER , CESD

Performer: DOE Laboratory

Additional: Collaborations , International Collaboration