Spatiotemporal variation and trend in carbon monoxide concentration over Africa: insights from MOPITT Data

Abstract

Carbon monoxide (CO) is an indirect greenhouse gas that has a significant impact on atmospheric chemistry. This study investigates the spatial and temporal variation and trend in CO concentrations over Africa from 2000 to 2019 using data from the Measurements of Pollution In The Troposphere (MOPITT) satellite instrument. The study classifies Africa into eight subregions based on emission inventories: northern hemisphere (NH), southern hemisphere (SH), arid (A), semi-arid north (SAN), savannah NH (SNH), savannah SH (SSH), semi-arid south (SAS), and tropical rainforest (TRF). It is observed that the northern hemisphere contributes about 54.07% of CO over Africa, while the SH accounts for 45.93%. The research reveals that the annual mean columnar CO over Africa declined significantly, with most subregions exhibiting a significant decrease in columnar CO, particularly over the NH windows. The columnar CO over Africa also revealed a seasonal pattern with two peaks in DJF (December-February) and SON (September–November), reflecting affluence from both hemispheres. The seasonal maxima and minima differ among subregions. The study further demonstrates that the tropospheric CO’s spatial and temporal variability in most subregions in Africa are sensitive to biomass burning, with MOPITT CO, MODIS fire count, and MODIS FRP being key parameters used to understand CO transport and fire emission across Africa. The study is relevant to climate researchers and policymakers seeking to understand the impact of CO on atmospheric chemistry, air quality, and climate change.