Parametric retrieval model for estimating aerosol size distribution via the AERONET, LAGOS station

Abstract

The size characteristics of atmospheric aerosol over the tropical region of Lagos, Southern Nigeria were investigated using two years of continuous spectral aerosol optical depth measurements via the AERONET station for four major bands i.e. blue, green, red and infrared. Lagos lies within the latitude of 6.465°N and longitude of 3.406°E. Few systems of dispersion model was derived upon specified conditions to solve challenges on aerosols size distribution within the Stokes regime. The dispersion model was adopted to derive an aerosol size distribution (ASD) model which is in perfect agreement with existing model. The parametric nature of the formulated ASD model shows the independence of each band to determine the ASD over an area. The turbulence flow of particulates over the area was analyzed using the unified number (Un). A comparative study via the aid of the Davis automatic weather station was carried out on the Reynolds number, Knudsen number and the Unified number. The Reynolds and Unified number were more accurate to describe the atmospheric fields of the location. The aerosols loading trend in January to March (JFM) and August to October (ASO) shows a yearly 15% retention of aerosols in the atmosphere. The effect of the yearly aerosol retention can be seen to partly influence the aerosol loadings between October and February.

Systemic Study of Aerosol Loading and Retention over Praia-Cape Verde: Satellite and Ground Observation Analysis

“…2). The maximum AOD value was found in June and July, which is very different from other locations in West Africa [3][4]. Also, the minimum AOD was found in January and December.…”

“…The aerosols loading over Praia was tested using equation (3). Equation (3) from the previous application [3] was built specifi cally for West African aerosol loading.…”

“…The aerosol dispersion model that was propounded by Emetere et al [3] was used to test the validity of the satellite and ground observations. The raw MISR and AERONET dataset was processed using the Excel package.…”

“…Hence the need to be certain about the permissive level of aerosols in the atmosphere is novel at this point. Aerosol loading over West Africa is already at its alarming state and new facts have shown that aerosol retention is very high in the region [3]. Hence, our main objective in this paper is to investigate the permissive level of aerosols over Praia's atmosphere.…”

“…Verheggen and Weijers [2] clarifi ed that aerosols cause cooling while black carbon aerosol causes warming. Emetere et al [3][4] worked on the cooling/warming effect of aerosol loading over some locations in West Africa. It was proposed that atmospheric aerosols coagulate in form of heterogeneous and homogeneous layers that have lifetimes which depend on how much aerosols are retained.…”