Impact of ship emissions on cloud properties over coastal areas

Abstract

Although land based emissions in Europe are decreasing, ship emissions continue to grow. The main emissions from ships can modulate cloud properties of coastal areas and are of direct relevance to the earth radiation budget. In this context, satellite data from AVHRR onboard NOAA-14 are evaluated for six years (1997-02) in order to assess impact of ship emissions on cloud properties over coastal areas. Study area was chosen in such a way that it includes the English Channel and top three polluting harbours in Europe. Results present first evidence of possible impact of ship emissions on both cloud albedo and cloud top temperature over coastal areas using long-term satellite measurements. Increase in cloud albedo (with corresponding decrease in cloud top temperature) and higher variability are observed over coastal areas. This effect is more pronounced for areas over and around harbours and the English Channel. It also confirms indirect aerosol effects. Copyright 2006 by the American Geophysical Union.