Trends and Interannual Variability of Satellite-Based Wind and Sea Surface Temperature over the Southern Ocean in the Recent Decade

Using satellite-based 10-m surface wind (SW), wind stress (WS) and sea surface temperature (SST) anomalies, trends and inter-annual variability during 1993 and 2008 over the Southern Ocean (SO) are addressed. The climatological mean (16 years average) indicates that negative wind stress curl diminished (enhanced) between 40°S and 60°S zonal strap region coincide with weak (strong) SW and warm (cold) SST anomaly during January (July). Annual climatology indicates that strong region of SW divides warmer waters northward with positive wind stress curl (WSCL) and colder waters southward with negative WSCL. The time series anomalies are smoothened with a 12-month running mean filter. The filtered area-mean time series anomalies of zonal and meridional component of SW and SST have linear trends of -0.0005 ± 0.0003 m/s/decade, 0.0012 ± 0.0002 m/s/decade and -0.00005°C ± 0.0001°C/decade, respectively. The SW anomalies show an increasing trend of 0.0013 ± 0.0002 m/s/decade, with the meridional (zonal) component exhibiting an increasing (decreasing) trend. The meridional component plays a critical role in heat transfer through atmospheric circulation. The WS and wind stress divergence exhibit increasing trends whereas wind stress curl shows a decreasing trend. The SST fluctuates close to zero with repeated high and low peaks at an interval of 2 - 3 years. We address the interannual variability by performing EOF analysis on SW, WS, WSCL and SST anomalies which have been passed through a 12-month running mean filter.