Ground and aircraft lidar measurements of sea salt and dust plumes with a small wide-field-of-view system

摘要

A small portable lidar system was recently used to derive aerosol optical concentrations from ground and aircraft platforms. The mini lidar uses a telescope setup with a relatively wide field of view allowing for measurements from close in (~60 m range) with no near field correction. In order to account for the large dynamic range, a custom logarithmic amplifier is used. Lidar measurements have been made in Hawaii and examples will be shown. More recently the Lidar was mounted on an aircraft for an experiment in the United Arab Emirates. In this case, the Lidar system was used to looking up, forward and down. The Lidar measurements looking up and down provided vertical profiles of aerosol concentrations. The lidar looking forward were used to derive quantitative aerosol extinction values using an existing and a new approach. Preliminary examples of this UAE data are shown. Being able to model aerosol phase functions is important for both satellite and Lidar aerosol retrievals. Mie theory is adequate for spherical particles but complex aerosols such as dust and organics are more difficult to model. Here we discuss phase function measurements we have made with our ground based polar nephelometer for sea salt and more recently for dust in the United Arab Emirates.