Soil Moisture Effects on Afternoon Precipitation Occurrence in Current Climate Models

Area of Science:

• Climate Science
• Atmospheric Science
• Earth System Science

Background:

• Soil moisture significantly influences land-atmosphere interactions and precipitation patterns.
• Understanding these feedbacks is crucial for accurate climate modeling and predicting extreme weather events.

Purpose of the Study:

• To evaluate soil moisture-precipitation feedbacks in a large ensemble of global climate model (GCM) simulations.
• To compare model simulations against observational data for spatial, temporal, and heterogeneity feedback characteristics.

Main Methods:

• Utilized a large ensemble of GCM simulations.
• Applied three distinct metrics to quantify spatial, temporal, and heterogeneity feedbacks between morning soil moisture and afternoon rainfall.
• Compared model-derived feedback metrics with observational data.

Main Results:

• Confirmed a dominantly positive spatial soil moisture-precipitation feedback in models, contrasting with observations.
• Observed better agreement between models and observations for temporal and heterogeneity feedbacks.
• Noted the largest intermodel variability in temporal and heterogeneity feedback metrics.

Conclusions:

• GCMs exhibit stronger spatial soil moisture-precipitation feedbacks compared to real-world observations.
• While models show some agreement with observations for temporal and heterogeneity feedbacks, significant intermodel variability exists.
• The combined feedbacks in models may lead to simulated localized precipitation persistence, differing from observed patterns.