ИСТИНА

Lake ice thickness (LIT) is a sensitive indicator of climate change, identified as a thematic variable of Lakes as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). Few methods have been developed during the last decades (Murfit et al 2021, Mangilli et al 2024), most of them using low frequencies microwave radar (L-,C-,X- and Ku-band). Here we propose to extend the range of frequencies for the retrieval of the LIT, using simultaneously Ku and Ka band radar, as this two frequencies will be onboard the next Copernicus CRISTAL mission (Kern et al 2016). Here we present data that were collected using a surface-based, fully-polarimetric (VV, HH, HV, and VH) Ku- and Ka-band Frequency Modulated Continuous Wave system (stroev et al 2020) over several Canadian frozen lake. In-situ measurement of the snow and ice layers and their respective properties have been made along the transect radar measurement. Then used similar yet different methods from Willatt et al 2023 to estimate the lake ice thickness and the impact of the snow cover on this retrieval. Lake Ice Thickness retrieval from the radar echograms showed good agreement with the in situ LIT measurement at both Ku and Ka Band. Impact of snow microstructure and snow/ice roughness on the retrieval is then discussed. The capacity of the Ka- band to retrieve LIT is also evaluated and compare with satellite altimetry waveforms. References: Kern, Michael, et al. The Copernicus polar ice and snow topography altimeter (CRISTAL) high-priority candidate mission.