The Antarctic Oscillation (AAO) is the dominant pattern of non-seasonal tropospheric circulation variations south of 20S, and it is characterized by pressure anomalies of one sign centered in the Antarctic and anomalies of the opposite sign centered about 40-50S. The AAO is also referred to as the Southern Annular Mode (SAM). There is a Northern Hemisphere analog to the AAO, and it is called the Arctic Oscillation (or Northern Annular Mode).

ICESat (Ice, Cloud, and Land Elevation Satellite) is a NASA/GSFC mission within the ESE (Earth Science Enterprise) program. The prime objective is to monitor the mass balance of the polar ice sheets and their contributions to global sea level change. Secondary goals are to measure cloud heights and the vertical structure of clouds and aerosols in the atmosphere, further to measure roughness, reflectivity, vegetation heights, snow-cover, and sea-ice surface characteristics, and to map topography of land surfaces. Note: ICESat is the renamed former "Laser Altimetry-1" mission.

Jason-1 (Joint Altimetry Satellite Oceanography Network) Mission. Jason is the name of a joint CNES/NASA oceanography mission series with the objective to monitor global ocean circulation, discover the tie between the oceans and atmosphere, improve global climate predictions, and to monitor events such as El Nino conditions and ocean eddies. The oceanography mission series is considered a cornerstone of GCOS (Global Ocean Observing System), a concept advocated by WMO (World Meteorological Organization), IOC (Intergovernmental Oceanographic Commission of the UNESCO), UNEP (United Nations Environmental Program), and ICSU (International Council of Scientific Unions).

Soil Moisture and Ocean Salinity (SMOS) mission is a microwave imaging satellite whose operation is led by ESA as part of their Earth Explorer missions. SMOS provides global observations on soil moisture and ocean salinity to improve our understanding of the water cycle and our weather forecasting ability.

There are no Arctic-wide or Antarctic-wide measurements of the volume of sea ice, but the volume of the Arctic sea ice is calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) developed at the University of Washington Applied Physics Laboratory/Polar Science Center. PIOMAS blends satellite-observed sea ice concentrations into model calculations to estimate sea ice thickness and volume. Comparison with submarine, mooring, and satellite observations help increase the confidence of the model results

Albedo is the ratio of the radiation (radiant energy or luminous energy) reflected by a surface to that incident on it. Snow and cloud surfaces have a high albedo, because most of the energy of the visible solar spectrum is reflected. Vegetation and ocean surfaces have low albedo, because they absorb a large fraction of the energy. Clouds are the chief cause of variations in the Earth's albedo.The land surface albedo is the ratio of the radiant flux reflected from Earth's surface to the incident flux. It is a key forcing parameter controlling the partitioning of radiative energy between the atmospheric and surface. In the case of vegetation, a reference surface is typically defined at or near the top of the canopy and must be specified explicitly. Surface albedo depends on natural variations, highly variable in space and time as a result of terrestrial properties changes, and with illumination conditions and human activities and is a sensitive indicator of environmental vulnerability.

ClONO2 - This is a stratospheric reservoir species for chlorine and nitrogen, two of the catalysts in the breakdown of ozone. It reacts with HCl at low temperatures on the surfaces of polar stratospheric clouds (PSCs over Antarctica and possibly in the stratosphere over the Arctic). That normally slow reaction heterogeneously produces molecular chlorine and nitric acid. The former outgases from the PSC surface and is quickly photolyzed by 450 nm or shorter wavelength light to form chlorine radicals which rapidly catalyze the breakdown of ozone (see chlorine monoxide). [Science; v 238; pages 1258-1260; 1987.] [Science; v 258; pages 1342-1345; 1992.]

The Arctic Oscillation (AO) is the dominant pattern of non-seasonal sea-level pressure (SLP) variations north of 20N, and it is characterized by SLP anomalies of one sign in the Arctic and anomalies of opposite sign centered about 37-45N. Additional information is available for the Arctic Oscillation (AO) and for the North Atlantic Oscillation (NAO), a close relative of the AO (http://jisao.washington.edu/ao/)

GRACE (Gravity Recovery And Climate Experiment) satellites mapped detailed measurements of the global gravitational fields with unprecedented precision. Data from GRACE satellites covered wide application areas. GRACE consists of two satellites (A, B) serving one mission.

Launched in October 2005, CryoSat was a next-generation radar altimetry mission, aiming to determine variations in the thickness of the Earth's continental ice sheets and marine ice cover. Primary objective is to test the prediction of thinning arctic ice due to global warming. CryoSat was supposed to be the first Earth Explorer Opportunity mission in ESA's Living Planet program, but was lost in a launch failure on 8 October 2005, prompting the development of a successor mission, CryoSat-2.