Depictions of surface moisture fluxes in high northern latitudes in reanalyses and a regional climate model

Freshwater fluxes in the Arctic basin have profound relevance to the global climate system. The accurate simulation of these fluxes is hampered by a variety of factors including the intricate physical processes involved and the broad range of time scales that are of interest. Perhaps most importantly, however, is the lack of reliable observations over large areas necessary for model validation. Previous study has shown that forecast precipitation (P) and evaporation/sublimation (E) fields in the NCEP/NCAR Reanalysis have substantial spatial deficiencies in the arctic, while fields of the combined quantity P minus E derived from reanalysis wind, moisture, and surface pressure fields are quantitatively superior. In this study a method of partitioning the derived moisture budget field into separate P and E fields is utilized as a diagnostic tool for further analysis of the spatial and temporal variability of the atmospheric moisture budget over the Arctic basin. The investigation consists of an evaluation of the derived reanalysis data sets in the Arctic over the extended forty year period, with comparisons to the Arctic Regional Climate System Model (ARCSyM), a coupled ocean-atmosphere-sea ice regional model that has been configured for high latitude simulations. Discussion centers on the veracity of the reanalysis data set, and useful results obtained from comparison to ARCSyM model variables. Additional sources of in situ observational data are also considered.