Forward model

Given the large range of spatial scales (from the 8 mm Ka-band wavelength) to ocean basin (10000 km) scales, the simulation of SKIM data is particularly complex. We have thus decomposed the problem in two:

  • high resolution simulations (SEEPS and the Deep Simulator part of the Scientific Workbench): these reproduce the moving surface of the ocean at the time scale of the pulse repetition frequency (PRF), up to a few cycles (seconds or minutes), and spatial scales shorter than the ground range resolution (4 m).
  • low resolution simulations, in which the current and waves signature are parameterized (based on the high resolution simulations) for each SKIM footprint (6 km diameter) and combined over one or many passes in large oceanic regions.

Inverse model

For each footprint, SKIM will produce Level 1 data with

  • backscatter and Doppler modulation as a a function of range
  • A line of sight velocity that contains effects of the spacecraft motion and radar beam pointing, and geophysical signatures of currents and waves

The inverse models start from these measured L1 data to produce a L2 ...