Earth Observations taken by the Expedition 15 Crew

ISS015-E-05977 (1 May 2007) --- Den Helder, Netherlands is featured in this image photographed by an Expedition 15 crewmember on the International Space Station. The city and harbor of Den Helder in the northern Netherlands has been the home port of the Dutch Royal Navy for over 175 years. Its favorable location provides access to the North Sea, and has made it an important commercial shipping port in addition to its strategic role. Bright red agricultural fields to the south of Den Helder indicate another noteworthy aspect of the region--commercial farming of tulips and hyacinth. This image is an oblique view--the camera is oriented at an angle relative to "straight down"--of the Den Helder region taken from the space station, which was located to the southeast, near Dulmen, Germany (approximately 225 kilometers away in terms of ground distance) when the image was acquired. In addition to the manmade structures of the Den Helder urban area (reddish gray to gray street grids) and dockyards to the east of the city, several striking geomorphic features are visible. The extensive gray mudflats, with their prominent branching pattern (top right), indicate that this image was acquired at low tide, and suggest the general low elevation of the region. Parallel wave patterns along the mudflats and in the Marsdiep strait are formed as water interacts with the sea bottom between Den Helder and Texel Island during tidal flow. Some ship wakes are also visible. According to scientists, the bright white-gray triangular region at the southern tip of Texel Island (bottom center) is a dune field, consisting mainly of eolian (windborne) sands deposited during the last Ice Age. Subsequent sea level rise and shoreline processes have mobilized and re-deposited these sands into their current configuration -- including a new dune field island to the southwest of Texel (bottom center).