Estimation of the Total Dust Column and Dry Deposition Flux over the Yellow Sea, China Based on Shipboard Sun Photometer Measurements: Case Study

Abstract

The total dust column and the dry deposition flux were calculated based on the optical properties that were measured by a shipboard sun photometer POM-01 MKⅡ in a cloud-free and nonfrontal dust condition on 24 April 2006. The total dust column was calculated by using an integration method of the particle size distribution; the mean value was 1.42±0.30 g m −2 . A linear correlation between the total dust column and the aerosol optical depth (AOD) with a linear factor of 2.7 g m −2 over the Sahara was applied to calculate the total dust column in this study; the results were lower than these calculated by the integration method. A reasonable factor of 3.2 g m −2 was achieved by minimizing the standard deviation (SD) of the two methods. The two layers model, which in- cludes the deposition processes of turbulent transfer, Brownian diffusion, impaction and gravitational settling over the sea's surface, was used to calculate the dry depo- sition flux; the mean value was 5.05±2.49 μg m −2 s −1 . A correlation among the total dust column, dry deposition flux, AOD, and effective radius was discussed. The cor- relation between the total dust column and the AOD was better than that between the total dust column and the effective radius; however, the correlation between the dry deposition flux and the effective radius was better than that between the dry deposition flux and the AOD.