Effects of rainfall on oil droplet size and the dispersion of spilled oil with application to Douglas Channel, British Columbia, Canada.
Raindrops falling on the sea surface produce turbulence. The present study examined the influence of rain-induced turbulence on oil droplet size and dispersion of oil spills in Douglas Channel in British Columbia, Canada using hourly atmospheric data in 2011-2013. We examined three types of oils: a light oil (Cold Lake Diluent - CLD), and two heavy oils (Cold Lake Blend - CLB and Access Western Blend - AWB). We found that the turbulent energy dissipation rate produced by rainfalls is comparable to what is produced by wind-induced wave breaking in our study area. With the use of chemical dispersants, our results indicate that a heavy rainfall (rain rate>20mmh-1) can produce the maximum droplet size of 300μm for light oil and 1000μm for heavy oils, and it can disperse the light oil with fraction of 22-45% and the heavy oils of 8-13%, respectively. Heavy rainfalls could be a factor for the fate of oil spills in Douglas Channel, especially for a spill of light oil and the use of chemical dispersants.
Marine Ecosystem Section, Ocean Ecosystem Sciences Division, Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, B2Y 4A2, Canada. Electronic address: Yongsheng.Wu@dfo-mpo.gc.ca.
Yongsheng
Y
Wu
State of the Ocean Section, Ocean Sciences Division, Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, V8L 4B2, Canada.
Charles G
CG
Hannah
State of the Ocean Section, Ocean Sciences Division, Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, V8L 4B2, Canada.
Pramod
P
Thupaki
National Lab for Coastal and Mountain Meteorology, Environment and Climate Change Canada, 201-401 Burrard Street, Vancouver, British Columbia V6C 3S5, Canada.
Ruping
R
Mo
Coastal Ecosystem Sciences Division, Fisheries and Oceans Canada, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, B2Y 4A2, Canada.
Brent
B
Law
D001955:British Columbia; D008956:Models, Chemical; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution / Q000032:analysis*; D011891:Rain; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014919:Wind
D010578:Petroleum; D014874:Water Pollutants, Chemical
Dilbit; Oil spills; Raindrops; Response plan; Turbulent energy dissipation rate