Open AccessSatellite mapping of rain‐induced nitric oxide emissions from soils
Author(s) -
Jaeglé L.,
Martin R. V.,
Chance K.,
Steinberger L.,
Kurosu T. P.,
Jacob D. J.,
Modi A. I.,
Yoboué V.,
SighaNkamdjou L.,
GalyLacaux C.
Publication year - 2004
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jd004787
Subject(s) - environmental science , soil water , tropics , atmospheric sciences , dry season , trace gas , tropospheric ozone , satellite , ozone , deposition (geology) , wet season , biomass (ecology) , troposphere , meteorology , agronomy , geography , soil science , geology , ecology , paleontology , cartography , aerospace engineering , engineering , biology , sediment
We use space‐based observations of NO 2 columns from the Global Ozone Monitoring Experiment (GOME) to map the spatial and seasonal variations of NO x emissions over Africa during 2000. The GOME observations show not only enhanced tropospheric NO 2 columns from biomass burning during the dry season but also comparable enhancements from soil emissions during the rainy season over the Sahel. These soil emissions occur in strong pulses lasting 1–3 weeks following the onset of rain, and affect 3 million km 2 of semiarid sub‐Saharan savanna. Surface observations of NO 2 from the International Global Atmospheric Chemistry (IGAC)/Deposition of Biochemically Important Trace Species (DEBITS)/Africa (IDAF) network over West Africa provide further evidence for a strong role for microbial soil sources. By combining inverse modeling of GOME NO 2 columns with space‐based observations of fires, we estimate that soils contribute 3.3 ± 1.8 TgN/year, similar to the biomass burning source (3.8 ± 2.1 TgN/year), and thus account for 40% of surface NO x emissions over Africa. Extrapolating to all the tropics, we estimate a 7.3 TgN/year biogenic soil source, which is a factor of 2 larger compared to model‐based inventories but agrees with observation‐based inventories. These large soil NO x emissions are likely to significantly contribute to the ozone enhancement originating from tropical Africa.