Multi-wavelength Scanning Lidar Measurements of the Effect of Wind Speed on Marine Aerosol Fields Generated by Breaking Waves

摘要

We present the results of our multi-wavelength scanning lidar investigations of time dependent 3-D marine aerosol fields as a function of meteorological parameters at a coastal site in Hawaii. We describe our measurements of salt-aerosol plumes generated at a reef >1.3 km from the lidar and their effect on the aerosol extinction coefficient. At typical trade wind speeds of ～7 m/s, plumes of salt spray have been observed to rise to heights of about 50 m above the reef. A time sequence of vertical scans at three wavelengths (355, 532, 1064 nm) was taken under light (1.9 m/s) wind conditions over the same reef. Large salt plumes more than 600 m high were found to develop under these conditions. The much greater height of light-wind plumes suggests that they are being dispersed less rapidly, allowing them to rise to greater heights because of the presence of thermals. Earlier data collected at Bellows showed reef plumes rising to 120 m in winds of 5 m/s, indicating a consistent trend of increasing plume height with decreasing wind speed.