Contribution of Byrd Polar Research Center number 1407.

Abstract The temporal consistency of the moisture fields (precipitation, evaporation and total precipitable water) from five global reanalyses is examined over Antarctica and the Southern Ocean during 1989ā€“2009. This concern is important given that (1) global rea-nalyses are known to be prone to inh...

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Bibliographic Details
Main Authors: J. P. Nicolas, D. H. Bromwich
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.669.9661
http://polarmet.osu.edu/PMG_publications/nicolas_bromwich_survgeophys_2011.pdf
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Summary:Abstract The temporal consistency of the moisture fields (precipitation, evaporation and total precipitable water) from five global reanalyses is examined over Antarctica and the Southern Ocean during 1989ā€“2009. This concern is important given that (1) global rea-nalyses are known to be prone to inhomogeneities and artificial trends caused by changes in the observing system, and (2) the period of study has seen a dramatic increase in the volume of satellite observations available for data assimilation. In particular, the study aims to determine whether the recent reanalyses are suitable for investigating changes in Antarctic surface mass balance. The datasets investigated consist of NCEP-2, JRA-25, ERA-Interim, MERRA and CFSR. Strong evidence of spurious changes is found in NCEP-2, JRA-25, MERRA and CFSR, although the magnitude, spatial patterns and timing of these artifacts vary between the reanalyses. MERRA exhibits a jump in Antarctic pre-cipitation-minus-evaporation (Pā€“E) and in Southern Ocean precipitation in the late 1990s. This jump is related to the introduction of sounding radiances from the Advanced Microwave Sounding Unit (AMSU). The impact of AMSU is also discernible, albeit less pronounced, in CFSR data. It is shown that ERA-Interim likely provides the most realistic