The Science

El Niño is a complex part of the climate system with extreme events occurring every 15 to 20 years that have major impacts on global water supplies. This study combined data derived from on-the-ground measurements and a suite of global datasets to determine where impacts on soil moisture from such events were most severe in the tropics and to explore possible links of these changes to other large-scale weather patterns.

The Impact

The study will provide a better understanding of where changes in moisture availability for plants are most severe in the tropics during El Niño to enable better predictions of impacts on the food supply and feedbacks of water from land back to the atmosphere through evapotranspiration. These findings can be used to guide decisions on where changes need to be made to water management systems during El Niño to offset expected decreases in moisture availability for crops and to improve global Earth system model predictions.

Summary

El Niño is an important part of the climate system that has widespread impacts on global water resource availability. This study employed a combination of modeled soil moisture datasets and on-the-ground measurements to determine what changes to expect for soil moisture during severe El Niño events. Supplemental datasets of evapotranspiration and precipitation were used to explore the possible link of these changes to non-El Niño related weather events. The analysis was focused on the humid tropics, which is important not only because of the higher severity of impacts due to its closer proximity to the El Niño source region, but also because historical observations in this region are generally sparse, which limits the ability to predict what will happen during an El Niño. Results indicate that the northern Amazon basin, as well as maritime regions of southeastern Asia, Indonesia and New Guinea will experience the largest reductions in soil moisture during the next severe El Niño. Information gleaned from the study can be used to develop better predictions of potential impacts on plants or the food supply so mitigation measures can be implemented, or to improve the understanding of tropical moisture feedbacks and how this might impact regional water supplies or the climate system.

Principal Investigator

Jeffrey Chambers
Lawrence Berkeley National Laboratory
jchambers@lbl.org

Program Manager

Daniel Stover
U.S. Department of Energy, Biological and Environmental Research (SC-33)
Environmental System Science
daniel.stover@science.doe.gov

Funding

This project was supported as part of Next-Generation Ecosystem Experiments—Tropics, funded by the Office of Biological and Environmental Research’s (BER) Environmental System Science program within the United States Department of Energy’s (DOE) Office of Science.

Related Links

• Associated data for this research available in NGEE—Tropics data archive (NGT0132-NGT0146 & NGT0148)

References