Marine Fog Over Northern Europe Based Upon Ship Observations For 1950–2007

The marine fog distribution over the northern European coastal areas is presented based on an analysis the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) ship observations taken during 1950–2007. Fog occurrence is reported in routine weather reports that are encoded from ICOADS ship observations. The number of observations is greatest in the North Sea and along the major shipping routes over the Atlantic while there are relatively lower in the northern Baltic.  Fog occurrence per 1 by 1 degree of lat/lon is calculated as the number of fog present weather observations divided by the total present weather observations. Along the southern coasts of the North Sea and the Baltic, the greatest seasonal fog occurrence approaches 7 % in Dec-Jan-Feb. For the entire North Sea, the seasonal median fog occurrence greatest in Mar-Apr-May (4.6 %), and least in Sep-Oct-Nov (2.0 %).  For the entire Baltic, the seasonal median fog occurrence is greatest in MAM (5.4 %) and least in SON (2.1 %).  In contrast, the fog to the west of the United Kingdom is greatest in Jun-July-Aug with uneven values but approaching 4 % and least in Dec-Jan-Feb with values less than 2 %.  Along Norway, north of 62° N, the fog is greatest in Jun-July-Aug with occurrences less than 3 %, and generally less than 2 % in the remainder of the year.  Along coastal France south of 48°N, Fog occurrence is less than 2 % in all seasons.