This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION The northern limit of the pack ice as defined by the 15% concentration of sea ice determined by the SSM/I instrument or its replacement. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Climate is affected by complex interactions between the sea ice and the atmosphere and ocean. The sea ice extent and concentration is determined by the oceanic and atmospheric forcing. There is evidence of variations in the sea ice extent and concentration on a synoptic time scale as storms pass through the region, and variations in sea ice extent on a multi-year time frame with forcing caused by the Antarctic circumpolar wave. Over the past 20 years, there is limited evidence of an increase in spatial ice extent and in the length of time that ice is present. Continued monitoring of sea ice extent and concentration may provide insights into the dynamics of the Southern Ocean and help to predict future climate. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM NASA uses a combination of satellite passive microwave sensors to measure the brightness values over sea ice covered regions. They then use an algorithm (referred to as the 'team' algorithm) to calculate the ice concentration and to determine the ice edge. The data are available globally on a daily or monthly basis. RESEARCH ISSUES Currently, NASA intends to maintain a series of satellite microwave sensors to continue to monitor sea ice extent and concentration. Ongoing research to interpret the data are currently being carried out at the AAD and the Antarctic and Southern Ocean CRC. Links with other indicators The sea ice extent and concentration has a large impact on the surface salinity and temperatures. Thus strong links with sea surface salinity and sea surface temperatures.

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Icebird Dates in ice: 4 Nov 1989 - 2 Dec 1989 Observers: Rob Kiernan, Martin Higham, others Summary of voyage track: 4/11 Ice edge at 58d22mS, 78dE 4-10/11 Steamed SW to approx 60dE 10-23/11 Vessel stuck in pack ice near 60dE 24-28/11 Vessel steamed eastward to near 77dE (Davis station) 30/11-2/12 Vessel steamed north to ice edge at 61d33mS, 82dE The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 21 Jul 1998 - 26 Jul 1998 Observers: Tony Worby, Vicky Lytle, Rob Massom, Anton Rada, Ian Allison Summary of voyage track: 21/7 Ice edge at approx. 64S, 147E 21-22/7 Steamed southward 22/7 Ship disabled due to engine room fire 22-25/7 Ship stationary in ice 25-26/7 Ship steamed north to ice edge at approx. 63S, 143E The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 17 Oct 1991 - 20 Oct 1991 Observers: Tony Worby Summary of voyage track: 17/10 Ice edge at 63d00mS, 137d52mE 17-18/10 Vessel steamed south to approx. 65S 19-20/10 Vessel steamed north to ice edge The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 26 Oct 1992 - 14 Nov 1992 Observers: Ian Allison, Tony Worby, Martin Higham Summary of voyage track: 26/10 Ice edge at approx. 60S, 85E 26/10 -1/11 Vessel steamed to Mawson 4-9/11 Vessel steamed from Mawson to Davis, transect in Prydz Bay 11-14/11 Vessel steamed from Davis to ice edge at approx. 61S, 86E. The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 22 Jul 1999 - 31 Aug 1999 Observers: Tony Worby, Ian Allison, Vicky Lytle, Rob Massom, Anton Rada, Matt Paget, Andrew Roberts Summary of voyage track: 22/7 Ice edge at approx. 62S, 143E 22/7 - 31/8 Complicated voyage track in and around the Mertz Glacier polynya CTD loops around the polynya region: Loop 1: 5-7/8 Loop 2: 12-14/8 Loop 3: 20-22/8 The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 08 Sep 1994 - 11 Oct 1994 Observers: Tony Worby, Ian Allison, Ross Edwards, Jason Phillips Summary of voyage track: 8/9 Ice edge at approx 60S, 150E 8-18/9 Vessel steamed along approx. 62S to 75E 19-24/9 Vessel steamed south along 75E 25-26/9 Vessel steamed into Davis 28-29/9 Vessel steaming north from Davis 30/9-7/10 Vessel beset in heavy ice 8-11/10 Vessel steamed north to ice edge at approx. 60S, 86E The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 20 Mar 1999 - 26 Mar 1999 Observers: Petra Heil Summary of voyage track: 20/3 Ice edge at approx. 65S, 65E 20-21/3 Ice edge to Mawson 24-26/3 Mawson to Davis The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Kapitan Khlebnikov Dates in ice: 17 Nov 1999 - 27 Nov 1999 Observers: Dan Kamien, Chris McKinley Summary of voyage track: 17/11 Ice edge at approx. 62S, 143E 17-21/11 From ice edge to Casey (109E) 25-27/11 From Casey to ice edge at approx. 63S, 123E The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Australia Vessel: Aurora Australis Dates in ice: 20 Oct 1993 - 01 Nov 1993 Observers: Martin Higham, Rob Kiernan, David N, D Murphy Summary of voyage track: 20/10 Ice edge at approx 60S, 114E 20-28/10 Vessel steamed westward to Mawson 30/10 - 2/11 Vessel steamed from Mawson to Davis No sea ice observations were made after Davis The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS