D. Jourdan et al., OCEANIC FRESH-WATER BUDGET AND TRANSPORT AS DERIVED FROM SATELLITE RADIOMETRIC DATA, Journal of physical oceanography, 27(3), 1997, pp. 457-467
Blended satellite-ship evaporation and SSM/I retrieved precipitation f
ields are used to compute oceanic freshwater budget (FWB) and transpor
t (FWT) over a 3-year period (1988-90). In order to validate the resul
ts, comparisons on monthly, seasonal, and multiyear average bases are
performed with ECMWF analyzed field and climatology respectively. For
May 1988, differences between ECMWF output and the present monthly est
imate are within 2 mm day(-1) (73 cm yr(-1)). Comparison with climatol
ogy shows that global discrepancies for longterm average drop down to
36 cm yr(-1) rms with a tendency for satellite-derived results to enha
nce climatological. features. Differences are found to correlate with
FWB patterns: large positive differences are observed in strong evapor
ative regions (eastern tropical Pacific), whereas negative differences
are observed over the eastern part of the intertropical convergence z
one and the northwestern part of the subtropical basins. Over the latt
er, precipitation is strongly dominant in our results, whereas climato
logy features rather slightly negative or positive contribution to the
FWB (i.e., evaporation). Over the Gulf Stream, for example, climatolo
gy indicates that ocean is losing about 100 cm yr(-1) freshwater while
FWB is balanced in our computation. FWT is then computed and compared
with climatological and in situ estimates. Differences with climatolo
gy are found to be 0.2 Sv rms (Sv = 10(6) m(3) s(-1)) in the Atlantic,
Indian, and Northern Pacific Oceans, and results generally match esti
mates derived from oceanographic data within the same error level, exc
ept in the Indian Ocean. The major disagreement is observed in the sou
thern Pacific Ocean where results, although confirming the direction o
f the FWT, suggest that 2.48 Sv is entering the Pacific Ocean, whereas
climatologies only give a northward transport equal to 0.26 Sv.