Weaker land-atmosphere coupling in global storm-resolving simulation.
Junhong Lee1, Cathy Hohenegger1
1Max Planck Institute for Meteorology, Hamburg 20146, Germany.
Summary
Global climate models show soil moisture-precipitation feedback is negative with explicit convection, unlike coarse-resolution models. This finding impacts understanding land climate change, including droughts and heatwaves.
Area of Science:
- Climate Science
- Atmospheric Science
- Hydrology
Background:
- The sign of soil moisture-precipitation feedback is debated, with coarse-resolution models suggesting positive feedback and regional models indicating negative feedback.
- Coarse-resolution models struggle to represent convection explicitly, while regional models often prescribe large-scale circulation.
Purpose of the Study:
- To investigate the soil moisture-precipitation feedback using global, coupled simulations with explicit convection.
- To compare these results with coarse-resolution simulations employing parameterized convection.
Main Methods:
- Global, coupled simulations were conducted for one year with explicit convection.
- Results were compared against coarse-resolution simulations that used parameterized convection.
Main Results:
- Simulations with explicit convection showed weaker and predominantly negative soil moisture-precipitation feedback.
- The explicit convection model favored triggering convection over dry soil in heterogeneous conditions, unlike the coarse-resolution model.
- Feedback between soil moisture, evapotranspiration, and precipitation was weaker with explicit convection, aligning better with observational data.
Conclusions:
- Coarse-resolution climate models may be inadequate for studying land-based climate change impacts like droughts and heatwaves.
- Explicit convection representation is crucial for accurately simulating soil moisture-precipitation feedback.
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