AGU 2023: Role of CCEWs in Subseasonal Precipitation in the East Pacific


December 12, 2023

Convectively Coupled Equatorial Waves has been thought to contribute to a large percentage of the fractional variance of subseasonal rainfall. In fact, with spectrally filtered precipitation compared to the subseasonal precipitation, we can see that certain CCEW can contribute up to 30% of the rainfall variance. 
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Fractional Variance of precipitation associated with different equatorial waves about the tropics. Precipitation data here comes from TRMM [1998 - 2019].
From the filtered variance, one can establish linearly regressed dynamic fields associated with waves at a basepoint, which we take to be the point in the eastern Pacific where variance maximizes. Below, we demonstrate the corresponding the filtered OLR aligned with different rainfall events and low-level dynamic fields in the eastern Pacific that are associated with different CCEWs that lead in precipitation fractional variance. 
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OLR-filtered for Easterly Waves and Linearly-Regressed Dynamic Fields
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OLR-filtered for Kelvin Waves and Linearly-Regressed Dynamic Fields
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OLR-filtered for MJO and Linearly-Regressed Dynamic Fields
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OLR-filtered for Mixed Rossby-Gravity Waves and Linearly-Regressed Dynamic Fields
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OLR-filtered for Rossby Waves and Linearly-Regressed Dynamic Fields