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The memory of convective precipitation is estimated via the analysis of the convective parameters convective available potential energy (CAPE) and convective inhibition (CIN). The variability of mixed layer (ML) CAPE and CIN in present-day climate is presented in terms of a linear decay time scale for short-term memory and the Hurst exponent for long-term memory (determined by detrended fluctuation analysis). Regional and global memory in CAPE and CIN is compared between observations (ECMWF re-analysis, in 1979–2001) and simulated data (ECHAM5/MPIOM, 20C simulation, in 1900–2001). Both datasets agree on the memory pattern in CAPE and CIN with highest values of the Hurst exponent along the equatorial Pacific which decrease towards higher latitudes; however, longest memory up to decades is found in CAPE south-east of Greenland. The memory in CIN is weaker than in CAPE regarding strength and spatial extent. To determine the origin of memory in CAPE and CIN, ML temperature and specific humidity, enthalpy, and latent heat equivalent of precipitable water (LPW) are analysed. In the tropics the spatial characteristics of the memory in CAPE coincide with memory in LPW, while in the extra-tropics ML temperature and humidity have the strongest impact. Copyright © 2010 Royal Meteorological Society |
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