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Water Cycle and Climate Extremes Modeling

Funding Program Area(s)
Project Type
Laboratory Science Focus Area (SFA)
Project Term
Project Team

Principal Investigator

Collaborative Institutional Lead

Project Participant


The Water Cycle and Climate Extremes Modeling (WACCEM) Scientific Focus Area represents sustained effort to advance predictive understanding of water cycle processes and their subseasonal-to-multidecadal variations and changes through foundational research using models, observations, and novel numerical experiments and analysis methods. With the ultimate goal of improving predictability of water availability and understanding societal vulnerability to extreme hydrologic events, WACCEM is organized around three overarching science questions:

  • How do large-scale circulation features modulate regional mean and extreme precipitation, and how will they change in the future?
  • What processes control mesoscale convection and associated warm season regional mean and extreme precipitation and how will they change in the future?
  • What do atmospheric circulation features and water cycle processes interact across scales, and how do they influence regional precipitation and its extremes?

Guided by these questions, WACCEM’s research is encapsulated in three research elements.

1. Large-Scale Circulation with the objectives to:

  • gain a better understanding of the mechanisms, such as the role of cloud radiative processes and energy transport pathways linking the ocean forcing to the monsoon, controlling the monsoon-ITCZ response to forcings; and  
  • develop a connection between the baroclinic annular model (BAM) and the evolution of weather events and extremes and understand the driving mechanisms for the enhancement of the BAM variability under warming.

2. Mesoscale Convective Systems with the objectives to:

  • characterize MCSs and their large-scale environments from the global tropics to the extratropics to understand their role in the climate system and potential changes in response to forcing; and
  • characterize the surface water balance and hydrologic floods associated with MCSs in the U.S. to advance an understanding of their role in surface hydrology and precipitation recycling.

3. Multiscale Interactions Between Convection and Large-Scale Circulation with the objectives to:

  • quantify the role of shallow, deep, and organized convection in atmospheric overturning circulation and precipitation in Asian and African monsoon systems; and
  • advance understanding of what controls the propagation of the MJO in the Indo-Pacific Maritime Continent and how the MJO influences extreme events such as atmospheric rivers and tropical cyclones.

This project was renewed for a three-year term, beginning in 2019. 

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