A Climatological Satellite Assessment of Absorbing Carbonaceous Aerosols on a Global Scale

Abstract

A global climatology of absorbing carbonaceous aerosols (ACA) for the period 2005–2015 is obtained by using satellite MODIS (Moderate Resolution Imaging Spectroradiometer)-Aqua and OMI (Ozone Monitoring Instrument)-Aura aerosol optical properties and by applying an algorithm. The algorithm determines the frequency of presence of ACA (black and brown carbon) over the globe at 1° × 1° pixel level and on a daily basis. The results of the algorithm indicate high frequencies of ACA (up to 19 days/month) over world regions with extended biomass burning, such as the tropical forests of southern and central Africa, South America and equatorial Asia, over savannas, cropland areas or boreal forests, as well as over urban and rural areas with intense anthropogenic activities, such as the eastern coast of China or the Indo-Gangetic plain. A clear seasonality of the frequency of occurrence of ACA is evident, with increased values during June–October over southern Africa, during July–November over South America, August–November over Indonesia, November–March over central Africa and November–April over southeastern Asia. The estimated seasonality of ACA is in line with the known annual patterns of worldwide biomass-burning emissions, while other features such as the export of carbonaceous aerosols from southern Africa to the southeastern Atlantic Ocean are also successfully reproduced by the algorithm. The results indicate a noticeable interannual variability and tendencies of ACA over specific world regions during 2005–2015, such as statistically significant increasing frequency of occurrence over southern Africa and eastern Asia.

A Global Climatology of Dust Aerosols Based on Satellite Data: Spatial, Seasonal and Inter-Annual Patterns over the Period 2005–2019

“…A remarkable feature in Figure 4 is the presence of DA in the southeastern Atlantic Ocean, off the coasts of Angola, in up to 3-16 days/month during the period from July to September, maximized in August (up to 19 days/month). This appearance of DA is observed over the same location, where absorbing carbonaceous aerosols (ACA) are observed and detected by a companion version of the present algorithm [99] using the same satellite data (MODIS and OMI). These ACA are associated with an effective westward transport of African biomass aerosols originating from extensive agricultural burning and wildfires over Angola and Congo [99].…”

“…This appearance of DA is observed over the same location, where absorbing carbonaceous aerosols (ACA) are observed and detected by a companion version of the present algorithm [99] using the same satellite data (MODIS and OMI). These ACA are associated with an effective westward transport of African biomass aerosols originating from extensive agricultural burning and wildfires over Angola and Congo [99]. These ACA aerosols are convectively uplifted to the free troposphere and subsequently transported westward (e.g., up to the Ascension Island 2000 km offshore continental Africa) by a well-established anticyclonic circulation induced by the semi-permanent sub-tropical anticyclone of the South Atlantic [100].…”