The 10 years long monitoring of climatically significant thermic characteristics of the surface of Southern ocean by means of in situ measurements and satellite remote sensing

Abstract

The hydrology of the Southern Ocean is characterized by several oceanic fronts that together form the largest Antarctic Circumpolar Current. The methodology of synoptical monitoring of fronts is based on observations during the seasonal maritime operations for supply of Russian Antarctic stations. It happens by use of continuous registrations of variability of horizontal gradients of temperature of sea surface layer (SSLT) in situ, and horizontal gradients of surface temperature (SST) from satellite infrared (IR) data, which are taken in real-time on board of research vessel. This makes possible more detailed definition of the horizontal gradients of thermic characteristics and latitudinal location of the fronts. It can be done by means of underway data of SSLT from vessel’s automatic meteorological station, with simultaneous GPS-registration of their spatial location, on the one side; and by precise definition of geographical position of fronts zones of SST from satellite high resolution IR-images of the ocean surface, on the other side. Such data obtained during regular sub-meridional voyages of research-supply vessels between Africa and Antarctica, helps more confident than before to judge about presence/absence of trends in inter-annual changes in the latitudinal location of the main fronts in the Southern Ocean. Such a trends can be considered as an evidence of substantial change of water circulation, and as the manifestations of global warming of the sea surface layer. Within Indian sector of the Southern Ocean during 2007–2016 was registered a trend in annual shifts of seasonal positions of climatic fronts to the south.