Satellite imagery and weather for the BESEX area, 15 February - 10 March 1973

The Bering Sea Experiment (BESEX) was conducted in February and March 1973 to study ice cover, sea state and zones of precipitation by means of airborne microwave radiometers over the Bering Sea. The images were computer processed from satellite data tapes. In processing the tapes, compensation was made for satellite attitude and altitude variations, as well as for image rectification. Visual imagery was taken in the 0.4 to 1.1-u range, and infrared imagery in the 8.0 to 13.0-u range

Trends and connections across the Antarctic cryosphere

Satellite observations have transformed our understanding of the Antarctic cryosphere. The continent holds the vast majority of Earth’s fresh water, and blankets swathes of the Southern Hemisphere in ice. Reductions in the thickness and extent of floating ice shelves have disturbed inland ice, triggering retreat, acceleration and drawdown of marine-terminating glaciers. The waxing and waning of Antarctic sea ice is one of Earth’s greatest seasonal habitat changes, and although the maximum extent of the sea ice has increased modestly since the 1970s, inter-annual variability is high, and there is evidence of longer-term decline in its extent

Spatial vision study "Polycentric territorial development (and urban-rural relationships) in NWE"

Final Report for North West Europe Interreg Secretaria

In search of an elusive Antarctic circumpolar wave in sea ice extents: 1978–1996

For ease in discerning an Antarctic circumpolar wave in the perimeter of the ice pack, we construct a time series of the sea ice extents (essentially the area within the ice perimeter) in 1-degree longitudinal sectors for the period 1978–1996, as observed with the multichannel microwave imagers on board the NASA Nimbus 7 and the DOD (Dept. of Defense) DMSP (Defense Meteorological Satellite Program) F8. F11, and F13 satellites. After converting the time series into complex numbers by means of a Hilbert transform, we decompose the time series of the 360 sectors into its complex principal components (CPCs), effectively separating the spatial and temporal values. Then we decompose the real and imaginary parts of the temporal portions of the first three CPCs (complex principal compenents) by Empirical Mode Decomposition into their intrinsic modes, each representing a narrow frequency band, resulting in a collection of three CPCs for each intrinsic mode. Finally, we reconstruct the data in two different ways. First, we low-pass filter the data by combining all of the intrinsic modes of each CPC with periods longer than two years, which we designate as low-pass filtered. Next, we select the intrinsic mode of each CPC with periods of approximately four years, which we designate the quasiquadrennial (QQ) modes. The low-pass filtered time series shows eastward propagating azimuthal motion in the Ross and Weddell Seas, but no clearly circumpolar motion. The QQ time series, on the other hand, clearly shows castward propagating circumpolar waves, but with occasional retrograde motion to the west

Seasonal variability of the East Greenland Coastal Current

The East Greenland Coastal Current (EGCC) is characterised as cold, low salinity polar waters flowing equatorwards on the east Greenland shelf. It is an important conduit of freshwater from the Arctic Ocean, but our present understanding of it is poor, outside of an assortment of measurements which stem mainly from summertime visits by research vessels. This manuscript first describes measurements from moored instruments deployed on the East Greenland shelf (~63°N) between 2000–2004. The measurements are then used to show that a high-resolution coupled ice-ocean global general circulation model supports a realistic representation of the EGCC. The results show that the EGCC exists throughout the year, and is stronger in winter than in summer. The model EGCC seawater transports are a maximum (minimum) in February (August), at 3.8 (1.9) x 106 m3 s-1. Freshwater transports, including modelled estimates of sea ice transport and referenced to salinity 35.0, are a maximum (minimum) in February (August) at 106 (59) x 103 m3 s-1. The model results show that wind and buoyancy forcing are of similar importance to EGCC transport. An empirical decomposition of the buoyancy-forced transport into a buoyancy-only component and a coupled wind and buoyancy component indicates the two to be of similar magnitude in winter. The model annual mean freshwater flux of ~80-90 x 103 m3 s-1 approaches 50% of the net rate of Arctic freshwater gain, underlining the climatic importance of the EGCC