Relationships among intraseasonal air-sea fluxes, rainfall, and SSTs in the NCEP CFSR and CFSv2 forecast during the DYNAMO period

Tropical intraseasonal rainfall variability has been found to be much more realistic in the recently developed NCEP Climate Forecast System Reanalyses (CFSR) and NASA Modern Era Retrospective-Analysis for Research and Applications (MERRA) than the previous NCEP/NCAR reanalysis (R1) and NCEP/DOE reanalysis (R2). This suggests an improved representation of large-scale circulation in the CFSR and MERRA compared to R1 and R2. In this study, we analyze intraseasonal surface fluxes related to the Madden-Julian Oscillation (MJO) in the CFSR during the DYNAMO period (October 2011 – March 2012). Relationships among rainfall, atmospheric dynamic fields, air-sea fluxes, and SST are diagnosed and compared with available observational estimates. Comparison is also made for the MERRA based on its available data. Real-time forecasts during the DYNAMO period from the NCEP Climate Forecast System Version 2 (CFSv2) are analyzed to assess its representation of the characteristics in the reanalyses and observations.