Keywords: urban boundary layers, remote sensing, lidar ceilometers, particulate matter, nocturnal boundary layers, air quality, air pollution, Vancouver, Canada, backscatter intensity
Comparison of tethered balloon vertical profiles of particulate matter size distributions with lidar ceilometer backscatter in the nocturnal urban boundary layer
A novel ceilometer validation is presented for a nocturnal elevated PM layer observed over Vancouver, British Columbia. The boundary-layer structure was confirmed by both meteorological and PM vertical profiles. This result is especially significant due to the low PM concentrations present during the observational period (a mean PM10 concentration of 10.6 μg m−3 was recorded) and suggests that ceilometers are able to resolve boundary-layer structure more subtle than that normally present during periods of poor air-quality. A direct relation between backscatter intensity and PM concentration suggests that not only may these relatively cheap, robust ceilometers be used to elucidate boundary-layer structure, but they represent a promising quantitative alternative to the measurement of PM concentrations that complements existing surface-based instrumentation. This study extends and confirms the growing body of evidence supporting the utility of ceilometers for making detailed, cost-effective measurements of the boundary-layer.