Open AccessComposite Singular Value Decomposition Analysis of Moisture Variations Associated with the Madden–Julian Oscillation: ERA-40 Analysis
Author(s) -
Bryan C. Weare
Publication year - 2005
Publication title -
journal of climate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.315
H-Index - 287
eISSN - 1520-0442
pISSN - 0894-8755
DOI - 10.1175/jcli3540.1
Subject(s) - madden–julian oscillation , outgoing longwave radiation , climatology , convection , moisture , environmental science , atmospheric sciences , humidity , divergence (linguistics) , boundary layer , troposphere , meteorology , geology , geography , physics , thermodynamics , linguistics , philosophy
The role of moisture variations in the initiation of Madden–Julian oscillation (MJO) variability is reexamined through composite singular value decomposition (CSVD) analyses using the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-yr Re-Analyses (ERA-40) data. The CSVD analyses at various time lags are carried out to discern the complex space–time relationships between convection identified using outgoing longwave radiation and 1000-hPa divergence, 850-hPa specific humidity, and surface evaporation. The most striking difference from the earlier analyses using NCEP–NCAR reanalysis data is that the observed relations between 20–100-day filtered OLR and ∇ · V1000 anomalies are weaker and less significant in the current analyses. On the other hand, both analyses show increasing low-level moisture near and to the east of the developing convection. Thus, both results imply that moisture preconditioning of convective events is not totally driven by boundary layer moisture convergence.