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Title: The atmospheric hydrologic cycle over the Southern Ocean and Antarctica from operational numerical analyses

Journal Article · · Monthly Weather Review
; ;  [1];  [2]
  1. Ohio State Univ., Columbus, OH (United States)
  2. Office of Naval Research, Arlington, VA (United States)

Moisture budget calculations for Antarctica and the Southern Ocean are performed using operational numerical analyses from several sources. The analyses are compared for an 8-yr period and evaluated against rawinsonde sites. The comparisons to East Antarctic and Macquarie Island rawinsondes show the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses to be superior in reproducing sounding values at each level. While results are highly variable, agreement of the ECMWF analyses to zonally averaged sounding moisture flux values along the East Antarctic coast is very close. The National Meteorological Center (NMC) and Australian Bureau of Meteorology analyses generally underestimate transport at each level; error cancellation occurs during vertical integration however. A comparison of moisture convergence for East Antarctica with values calculated from rawinsonde data indicates the ECMWF analysis is within 5 mm per yr of the observed value, while the NMC result is severely deficient. Comparison of the moisture transport convergence derived from the numerical analyses with previous moisture flux studies over the Southern Ocean reveals general agreement in the location of the boundary between the moisture source and sink. The ECMWF and NMC analyses place the convergence maximum slightly farther south than has been previously found. It is inferred that this results from the blocking effect of the Antarctic coastal topography. At full resolution this point is at approximately 64{degree}S. Long-term net precipitation derived from analyses is somewhat smaller than values determined by glaciological methods. Net precipitation varies interannually by 25%, with most of the variation concentrated in the South Pacific sector. The results offer a positive outlook for determining continental-scale precipitation trends in Antarctica through atmospheric methods and demonstrate that the ECMWF analyses provide generally good estimates. 56 refs., 21 figs., 3 tabs.

OSTI ID:
486289
Journal Information:
Monthly Weather Review, Vol. 123, Issue 12; Other Information: PBD: Dec 1995
Country of Publication:
United States
Language:
English