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Why is the Indo-Gangetic Plain the region with the largest NH3 column in the globe during pre-monsoon and monsoon seasons?
- Source :
- Atmospheric Chemistry and Physics. 20:8727-8736
- Publication Year :
- 2020
- Publisher :
- Copernicus GmbH, 2020.
-
Abstract
- Satellite observations show a global maximum in ammonia (NH3) over the Indo-Gangetic Plain (IGP), with a peak from June to August. However, it has never been explained explicitly. In this study, we investigated the causes of high NH3 loading over the IGP during the pre-monsoon and monsoon seasons using WRF-Chem (Weather Research and Forecasting model coupled to chemistry). The IGP has relatively high NH3 emission fluxes (0.4 t km−2 month−1) due to intensive agricultural activities and high air temperature from June to August. Additionally, low sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions and high air temperature limit the gas-to-particle conversion of NH3, particularly for ammonium nitrate formation. Moreover, the barrier effects of the Himalayas in combination with the surface convergence weaken the horizontal diffusion of NH3. The high NH3 loading over the IGP mainly results from the low gas-to-particle partitioning of NH3 caused by low SO2 and NOx emissions. It contrasts to those in the North China Plain, where high SO2 and NOx emissions promote the conversion of gaseous NH3 into particulate ammonium.
- Subjects :
- Atmospheric Science
010504 meteorology & atmospheric sciences
Ammonium nitrate
Particulates
010502 geochemistry & geophysics
Monsoon
Atmospheric sciences
01 natural sciences
Ammonia
chemistry.chemical_compound
chemistry
Weather Research and Forecasting Model
Ammonium
NOx
Sulfur dioxide
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 16807324
- Volume :
- 20
- Database :
- OpenAIRE
- Journal :
- Atmospheric Chemistry and Physics
- Accession number :
- edsair.doi...........3b9ab21d9eecef04708881cfca1e2c07