Satellite microwave remote sensing of landscape freeze-thaw status related to frost hazard monitoring

Approximately 66 million km2 (~52.5%) of the global land area undergoes seasonal freezing and thawing that constrain terrestrial ecosystem processes and land surface water mobility. The landscape freeze“thaw (FT) regime is closely linked to vegetation productivity, snowmelt dynamics, land surface temperature, and permafrost occurrence. Satellite microwave remote sensing is well suited for global monitoring of FT state dynamics, day or night, owing to reduced microwave sensitivity to signal degradation by atmospheric cloud/aerosol contamination and solar illumination effects. The landscape FT status derived from satellite microwave remote sensing detects the predominant frozen or nonfrozen status of the land surface and can be used for deriving a range of frost-related metrics, including frost timing, extent, and duration. Similar overlapping satellite microwave Earth observations extending over multiple decades have also enabled the development of global environmental data records documenting longer-term FT trends and associated climate indicators. This chapter provides an overview of (1) satellite microwave remote sensing of frost-related impacts on terrestrial ecosystems, including vegetation growth, snowpack icing events, animal habitats, and human infrastructure; (2) the physical basis and common techniques underpinning satellite microwave remote sensing of landscape FT status; (3) recent progress in applying these techniques by using high temporal repeat global satellite passive microwave remote sensing; and (4) satellite detection of frost-related damage to vegetation growth, using climate indicators derived from the fusion of visible”infrared and microwave sensor retrievals. Recent advances toward developing finer-resolution and lower-frequency FT observations are also summarized.