- Antarctic ice-shelf calving-front monitoring and basal melt — SAR imagery and laser altimetry reveal calving-front retreat, rift propagation and basal melt on Antarctic ice shelves year-round, through cloud and polar night. Together they quantify the processes that govern future sea-level rise.
- Greenland ice-sheet mass balance and outlet glacier dynamics — Three satellite techniques, gravimetry, altimetry and SAR, together constrain how fast Greenland is losing ice and where. Each method has distinct error sources; reconciling them is the science.
- Harmful algal bloom detection and extent mapping — Toxin-producing phytoplankton blooms threaten fisheries, drinking water and public health, yet cloud cover and coarse revisit rates make reliable single-pass detection difficult. Multi-sensor compositing and Sentinel-3 OLCI's 300 m ocean-colour products now give coastal managers a practical detection workflow.
- Iceberg detection and drift tracking — From Antarctic tabular giants to sub-10-metre growlers, satellite SAR and optical imagery can locate, classify and track icebergs across open ocean and sea-ice fields. The hazard to shipping lanes and subsea pipelines makes positional accuracy and revisit rate the critical variables.
- Ocean colour and marine primary productivity estimation — Ocean colour radiometry retrieves chlorophyll-a concentration from the spectral ratio of water-leaving radiance, turning subtle blue-to-green shifts into estimates of phytoplankton biomass and marine net primary productivity. Atmospheric correction dominates the challenge: more than 90 % of the signal at the sensor is atmosphere, not ocean.
- Ocean current and mesoscale eddy tracking from altimetry — Radar altimetry measures sea-surface height to within centimetres, revealing geostrophic currents and the mesoscale eddies that redistribute heat, carbon and marine life across ocean basins. Multi-mission merged products turn sparse along-track swaths into actionable gridded current fields.
- Permafrost active-layer dynamics from InSAR surface deformation — Repeat-pass SAR interferometry detects the seasonal heave and subsidence of permafrost active layers at centimetre scale, revealing where frozen ground is losing structural integrity and releasing stored carbon.
- Polar shipping-route ice condition monitoring — Satellite SAR and passive-microwave data now give voyage planners near-daily ice charts along the Northern Sea Route and Northwest Passage. This page explains how those charts are made, what they miss, and when you need something more.
- Polynya detection and polar ocean heat-flux estimation — Polynyas are persistent or transient gaps in the sea-ice pack where the ocean loses heat to the atmosphere at extraordinary rates. Satellite passive microwave and thermal infrared sensors can locate them reliably, but separating thin new ice from open water demands careful multi-sensor reconciliation.
- Sea-ice extent and concentration mapping — Passive microwave radiometry has tracked sea-ice extent and fractional concentration daily since 1979, but its 25 km resolution floor hides the leads and polynyas that matter most. Sentinel-1 SAR closes that gap at the cost of coverage and latency.
- Sea-ice thickness from radar and laser altimetry — Sea-ice thickness cannot be measured directly from orbit, so satellites measure freeboard and work backwards through isostatic balance. The method is powerful but depends critically on snow-load assumptions that vary across ice types and seasons.
- Sea-surface salinity mapping from L-band radiometry — L-band microwave radiometers measure ocean surface salinity by detecting shifts in seawater's dielectric constant, but the signal is faint, cold water blunts it further, and radio interference corrupts coastal swaths. Three missions now hold a decade of global salinity records.