Atmospheric water budgets over tropical oceans

There are numerous datasets from which global or near-global gridded water vapor transport divergence, precipitation (P) and evaporation (E) can be obtained. Both observation-based (e.g. GPCP, SeaFlux, OAFlux) and model-based (e.g. ECMWF ERA interim, MERRA) data products can be used to investigate how different data combinations contribute to closing the water balance where divergence approximates P-E. An assessment of the sensitivity of the divergence, precipitation and evaporation components to different datasets is made, with the primary focus being the evaporation component of the vapor transport balance. Evaporation estimates can be obtained from global flux products (SeaFlux, OAFlux), but they can also be calculated through theoretically-derived relationships between near-surface wind speed and specific humidity (and therefore also sea surface temperature - SST). Satellite-derived data products contribute to the Blended Sea Winds and SST datasets with the effect of these changes on evaporation evaluated. Observational specific humidity datasets are limited and therefore are only sourced from the model data or derived from its relationship with SST. The datasets utilized contain daily or sub-daily resolution and at least a 1° x 1° resolution to create a monthly-averaged time series for tropical ocean regions. Factors that influence E and contribute to balancing the water budget in this region are determined, for the period 1998 - 2009. Insight into the variability and sensitivity of the divergence, P and E terms from the different data sources will improve understanding of water budget components.