This image displays an ice-laden segment of the White Sea on Russia’s northern coast. Flowing into it from the southeast is the Severnaya Dvina, with the city of Archangel located on its eastern bank. To the north is the peninsula of Kolskiy Poluostrov, Russia’s northwestern extremity. Since the 1600s, Archangel has been considered the cradle of Russian shipbuilding and is of major strategic importance as a port, from where lumber, cut from the surrounding forests, is exported throughout the world.
This image illustrates that during early April the sea that surrounds the port is still heavily infested with ice floes. It is also interesting to note the offshore barrier along the eastern coastline that has presumably been constructed to provide an ice-free passage for this important shipping route.
Instrument: Advanced Synthetic Aperture Radar (ASAR)
Mode: Image Swath 6
Acquisition date: 08 April 2002
Orbit number: 00554
Orbit direction: Ascending
Resolution: 30 metres
Instrument Features: Envisat’s ASAR instrument is the first permanent space-based radar to incorporate dual-polarisation capabilities - the instrument can transmit and receive signals in either horizontal or vertical polarisation. This Alternating Polarisation (AP) mode can improve the capability of a SAR instrument to classify different types of terrain. Because the reflective properties of a surface are dependant on the polarisation of the incoming radar signal, the use of more than one type of polarisation provides valuable extra information.