摘要: |
On November 22, 2012, at about 8:35 a.m., thick fog resulted in a 140 vehicle accident near Beaumont, Texas. Remarkably, only two people died and 80 people were injured and required hospital care. On January 29, 2012, about 4:00 a.m., amidst thick fog and smoke on I-75 south of Gainesville, Florida, 11 people were killed and 18 hospitalized in a multi-vehicle crash. Nationally, there are about 38,000 fog related vehicle accidents each year resulting in about 620 fatalities. In Florida, between 2002 and 2009, 299 people died in vehicle crashes related to fog and smoke conditions on Florida highways. This is more than those who died from hurricanes and lightning in Florida over the same time period. Fog is a cloud on the ground. All types of fog require ubiquitous cloud condensation nuclei (CCN) and can form with a relative humidity less than 100%. The opaqueness (heaviness or thickness) of fog may be substantially increased by the presence of smoke, due to the increase of CCN. Fog is both spatially and temporally variable. With observation equipment widely dispersed, the challenge is how to forecast the occurrence of fog from observation far removed from the location of fog occurrence. With the available data from 2002 to 2009, the location and frequency of fog was determined, thus forming a fog climatology. Using the data from that study, researchers evaluated fog-prediction techniques and made recommendation to improve fog-warning systems along Florida's highways. |