Optical properties of tropospheric aerosols determined by lidar and spectrophotometric measurements (Photochemical Activity and Solar Ultraviolet Radiation campaign)

Abstract

We present the results of the aerosol measurements carried out over the Aegean Sea during the Photochemical Activity and Solar Ultraviolet Radiation campaign held in Greece during June 1996. Simultaneous observations performed with a lidar and a double-monochromator spectrophotometer allowed us to retrieve the optical depth, the Angström coefficient, and the backscatter-to-extinction ratio. The Sun photometric data can be used to improve quantitative aerosol measurements by lidar in the Planetary Boundary Layer. Systematic errors could arise otherwise, because the value of the backscatter-to-extinction ratio has to be supplied. Instead this ratio can be retrieved experimentally by use of an iterative solution of the lidar equation.

A case study of dust aerosol radiative properties over Lanzhou, China

“…It can be taken in the region where the lidar return signal followed the molecular profile (Marenco et al, 1997). Klett (1981) shows that the backward solution is generally stable.…”

Characteristics of the spatial distribution and yearly variation of aerosol optical depth over China in last 30 years

“…However, it is not feasible to achieve the detailed spatial and temporal distribution of aerosols because of the scarcity of the direct observational data of aerosols. Hence, in addition to enhancement of field observation campaign, many scientists have made great effort to derive aerosol information from long history of other recorded meteorological data, such as solar radiation [King et al, 1978;Vasilyev et al, 1995;dacovides et al, 1996;Qiu, 1997;Marenco et al, 1997;Qiu, 1998;Gueyrnard, 1998]. Considering that large-scale direct aerosol observation is infeasible at present and even in the near future, indirectly retrieving aerosol information from other data is quite practicable.…”

Retrieval of downwelling UV actinic flux density spectra from spectral measurements of global and direct solar UV irradiance

“…Global irradiance is also known as the cosine-weighted irradiance, because all photon fluxes are sensed as their product with the cosine of their angle of incidence. During the last few years the direct component of solar radiation has been also included in the protocol of the measurements of several UVmonitoring stations, because of its particular importance in determining the column abundance of various atmospheric species, such as ozone and aerosols [Huber eta/., 1995;Marenco et al, 1997].…”