Geoscience Reference
In-Depth Information
Fig. 16 Top left: SMOS 10-day SSS field in June 2010. Top right: time series of the surface salinity S(t) at
the black point shown in the top left figure (35W; 16N). Red: SMOS SSS, blue curve: local mean
climatological annual cycle at that point S
o
(t). The resulting time series for the SMOS anomaly DSSS at that
point is shown in the middle panel, right plot. The green horizontal lines are indicating ± one standard
deviation of the local SSS anomalies, r
S.
In the middle and bottom left panels, we show the corresponding
OAFlux evaporation and TRMM 3B42 precipitation field (mm/day). The time series of the precipitation
anomaly at the point is shown in the bottom right panel
in these key regions of the marine branch of the global hydrological cycle. In that context,
SMOS SSS may therefore be an interesting data set for assimilation into ocean models in
the perspective of better constraining oceanic precipitation forcing terms.
4.4 Large-scale SSS Interannual Variability in Tropical Indian and Pacific Oceans
In the Indian and Pacific oceans, the precipitation impact on the large-scale SSS variability
can also be observed from SMOS and ISAS monthly maps.
The 2010-2011 period was characterized by a strong La Ni ˜ a event lasting from July
2010 to March 2011 and by an Indian Ocean Dipole (IOD) index in negative phase in
September-November 2010 and in positive phase during about the same months in 2011
(see Fig.
19
). Such events are known to generate large-scale SSS signatures in the tropics
(e.g., Gouriou and Delcroix
2002
; Singh et al.
2011
; Grunseich et al.
2011
) and are clearly
depicted in the SSS signals in both the ISAS and the SMOS monthly difference maps
between 2010 and 2011 for both July and November (Fig.
20
).
