Test Cards for ESA Earth Explorer CryoRad

Four different test cards are designed for ESA's Earth Explorer CryoRad to address key questions related to its primary applications: ocean, sea ice and land, as well as critical aspects of instrument performance such as spatial resolution, channel alignment and geolocation accuracy. Each test card focuses on a specific scenario and objective and is generated for 0.4 GHz, 1.4 GHz and 2.0 GHz, covering the full CryoRad frequency range. The cards are provided in three different formats: float32 GeoTIFF, 8-bit GeoTIFF and PNG, to ensure readability and accessibility for all users.Line test cards show a sharp contrast transition between land and ocean or ice and ocean. This helps determine how far from the ice edge a "clean" ocean signature can be detected, as smearing at high-contrast transitions significantly affect retrieval accuracy.Bornholm test cards show the silhouette of Bornholm, so geolocation and channel alignment can be tested in order to determine the percentage of the pure land signature that appears in the actual coastline.Modis test cards show a realistic sea ice scenario including the ice edge, varying concentrations and different floe sizes. This helps determine what spatial scales of sea ice concentration are derived at different frequencies.Eddy test cards show synthetic eddies of varying sizes and spacing in order to determine what sizes and spacing of eddies can be resolved by the instrument.The value in the test cards represent a brightness temperature in Kelvin [K]. When visualizing the cards, the following colorbar ranges are recommended and are also used for generating the PNG versions:<br>Line: 50-250 K<br>Modis: 50-250 K<br>Eddy: 50-150 K<br>Bornholm: 50-250 K