Estimation of degree of sea ice ridging in the Bay of Bothnia based on geolocated photon heights from ICESat-2

Abstract. We present a comparison of Ice, Cloud and land Elevation Satellite-2 (ICESat-2) geolocated photon heights operational ice charts from the Finnish Ice Service in Bay Bothnia spring 2019. show that ICESat-2 (IS2) retrievals areas with different ridging characteristics, more precisely degree (DIR), differ significantly. DIR is particularly useful parameter for navigators, as it provides information on how difficult to navigate through an area based e.g. sail distribution sea ridges. estimates are included Baltic Sea primarily situ observations active icebreaker fleet. may potentially be estimated IS2. also IS2 measurements Sentinel-1 synthetic aperture radar frames, discussing several individual cases elevation behaviour over ice. suggest data can benefit international services, especially if time-critical height product were made available. Furthermore, we difference between highest mean elevations (elevation anomalies) correspond expected ridge our study area. Our one first steps creating applications beyond traditional goal freeboard thickness retrieval