Global Ice and Land Climate Studies Using Scatterometer Image Data

The original application for scatterometers was for them to measure winds by monitoring the scattering of radar waves. However, this data has many applications beyond wind, one of which is to determine seasonal and interannual variability and the possible relations to climate change. Now that the Scatterometer Climate Record Pathfinder (SCP) is producing and publishing non-ocean scatterometry imagery and data, these applications of scatterometry can be explored. Applications include:

1. Monitoring ice sheets
• Long term viability
• Amount of melt
• Snow/ice accumulation and melt zones
• Wind measurement
• For more information, look into “Quantifying Vulnerability of Antarctica Ice Shelves to Hydrofracture using Microwave Scattering Properties” on the MERS website!
2. Monitoring sea ice
• Identify/map sea ice extent
• Compare ice and winds to examine turbulent heat fluxes that affect the marginal ice zones
• Ice velocity fields to examine heat fluxes that affect the ocean and the atmosphere and to estimate ice deformation and growth
3. Iceberg tracking
4. Monitoring the terrestrial biosphere (the part of the atmosphere that life is in)
• Identify the moisture content change
• Examine the seasonal freeze-thaw cycle
• Examine different types of vegetation and land surface covers and how they vary, as seen in Figure 1.
• Potentially identify the long-term climate impacts on moisture availability and vegetation loss/recovery

We can get more applications out of scatterometers by configuring them in different ways. Some different methods of configuring include:

• Using different sensor frequencies
• Monitoring the response between different polarizations
• Using a range of incidence angles
• Using different orientations

Furthermore, because scatterometers are so accurate, relatively small changes can be examined.

Properties that change backscatter include:

• Surface roughness
• Moisture content
• Leaf size and density
• Branch orientation
• Alignment of the surface to the scatterometer
• The physical characteristics of the scattering medium (like snow grain size, brine concentration, canopy leaf density, etc)
• The phase state of water present

Figure 1 shows how scatterometers were able to determine different types of vegetation in Africa.

References: Long, D. G., M. R. Drinkwater, B. Holt, S. Saatchi, and C. Bertoia, Global ice and land climate studies using scatterometer image data, EOS Transactions, AGU, 82(43), 503, 2001. Long, D. G., M. R. Drinkwater, B. Holt, S. Saatchi, and C. Bertoia, Global ice and land climate studies using scatterometer image data, EOS Transactions Electronic Supplement, AGU, https://www.agu.org/eos_elec/010126e.html, 2001.

For more information, please go to https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/01EO00303