Remote Sensing of Ice Phenology and Dynamics of Europe’s Largest Coastal Lagoon (The Curonian Lagoon)

Abstract

A first-ever spatially detailed record of ice cover conditions in the Curonian Lagoon (CL), Europe’s largest coastal lagoon located in the southeastern Baltic Sea, is presented. The multi-mission synthetic aperture radar (SAR) measurements acquired in 2002–2017 by Envisat ASAR, RADARSAT-2, Sentinel-1 A/B, and supplemented by the cloud-free moderate imaging spectroradiometer (MODIS) data, are used to document the ice cover properties in the CL. As shown, satellite observations reveal a better performance over in situ records in defining the key stages of ice formation and decay in the CL. Using advantages of both data sources, an updated ice season duration (ISD) record is obtained to adequately describe the ice cover season in the CL. High-resolution ISD maps provide important spatial details of ice growth and decay in the CL. As found, ice cover resides longest in the south-eastern CL and along the eastern coast, including the Nemunas Delta, while the shortest ice season is observed in the northern CL. During the melting season, the ice melt pattern is clearly shaped by the direction of prevailing winds, and ice drift velocities obtained from a limited number of observations range within 0.03–0.14 m/s. The pronounced shortening of the ice season duration in the CL is observed at a rate of 1.6–2.3 days year‒1 during 2002–2017, which is much higher than reported for the nearby Baltic Sea regions. While the timing of the freeze onset and full freezing has not changed much, the dates of the final melt onset and last observation of ice have a clear decreasing pattern toward an earlier ice break-up and complete melt-off due to an increase of air temperature strongly linked to the North Atlantic Oscillation (NAO). Notably, the correlation between the ISD, air temperature, and winter NAO index is substantially higher when considering the lagoon-averaged ISD values derived from satellite observations compared to those derived from coastal records. The latter clearly demonstrated the richness of the satellite observations that should definitely be exploited in regional ice monitoring programs.

Sediment Transport Mechanisms in a Lagoon with High River Discharge and Sediment Loading

“…The satellite ice cover data ( Figure 3B) were acquired from the synthetic aperture radar (SAR) measurements from three Earth observation missions: Envisat ASAR, RADARSAT-2, and Sentinel-1A and 1B, complemented by cloud-free Moderate Imaging Spectroradiometer (MODIS) images. For the period 2004-2015, in total, 475 SAR and 64 MODIS images were processed by manually digitizing ice polygons using ArcGIS software, which were then validated with ground observations, showing that satellite data in many cases has better performance than in situ data for defining the key stages of ice cover formation and decay [56]. These polygon datasets were converted to regular grid points and then used to spatially interpolate onto the finite element grid.…”

Remote Sensing of Ice Conditions in the Southeastern Baltic Sea and in the Curonian Lagoon and Validation of SAR-Based Ice Thickness Products

“…In severe winters, the Danish Straits and the southern Baltic Proper are also covered with ice [1]. In the Southeastern Baltic (hereinafter, SEB), ice cover also forms within brackish and shallower estuaries-the Vistula and the Curonian Lagoons-that are at least partially ice-covered every year [2,3].…”

“…The largest European freshwater estuary, the Curonian Lagoon (hereinafter, CL) is also affected by regional climate change [3,15]. During the last two decades, mean winter air temperature over the CL increased by 1.7 • C. The ice season duration in the lagoon is very irregular, and the ice cover can form and break-up several times per season.…”

“…However, their use in the SE Baltic Sea is limited until now. The only exclusion is a recent study presented in [3], where the authors used multi-mission SAR data to analyze ice phenology and dynamics in the Curonian Lagoon, importantly showing a pronounced shortening of ice season duration observed over this region during 2002-2017. Yet, this study provides no information about the ice conditions in the adjacent coastal area of the SE Baltic Sea.…”

Editorial for the Special Issue “Combining Different Data Sources for Environmental and Operational Satellite Monitoring of Sea Ice Conditions”

“…Idzelytė et al [10] used images from different satellite SAR systems and Moderate Resolution Imaging Spectroradiometer (MODIS) acquired in a time interval from 2002 to 2017 to document ice cover conditions in the Curonian Lagoon (CL), Europe's largest coastal lagoon located in the southeastern Baltic Sea. Using both satellite and in-situ data, the authors generate ice season duration (ISD) maps that reveal spatial details of ice growth and decay in the CL.…”