In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 20, No. 5 ( 2020-03-04), p. 2667-2693
Abstract:
Abstract. The Model Inter-Comparison Study for Asia (MICS-Asia)
phase III was conducted to promote understanding of regional air quality and
climate change in Asia, which have received growing attention due to the
huge amount of anthropogenic emissions worldwide. This study provides an
overview of acid deposition. Specifically, dry and wet deposition of the
following species was analyzed: S (sulfate aerosol, sulfur dioxide
(SO2), and sulfuric acid (H2SO4)), N (nitrate aerosol,
nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid
(HNO3)), and A (ammonium aerosol and ammonia (NH3)). The wet
deposition simulated by a total of nine models was analyzed and evaluated
using ground observation data from the Acid Deposition Monitoring Network in
East Asia (EANET). In the phase III study, the number of observation sites
was increased from 37 in the phase II study to 54, and southeast Asian
countries were newly added. Additionally, whereas the analysis period was
limited to representative months of each season in MICS-Asia phase II, the
phase III study analyzed the full year of 2010. The scope of this overview
mainly focuses on the annual accumulated deposition. In general, models can
capture the observed wet deposition over Asia but underestimate the wet
deposition of S and A, and show large differences in the wet deposition of N.
Furthermore, the ratio of wet deposition to the total deposition (the sum of
dry and wet deposition) was investigated in order to understand the role of
important processes in the total deposition. The general dominance of wet
deposition over Asia and attributions from dry deposition over land were
consistently found in all models. Then, total deposition maps over 13
countries participating in EANET were produced, and the balance between
deposition and anthropogenic emissions was calculated. Excesses of
deposition, rather than of anthropogenic emissions, were found over Japan,
northern Asia, and southeast Asia, indicating the possibility of long-range
transport within and outside of Asia, as well as other emission sources. To
improve the ability of models to capture the observed wet deposition, two
approaches were attempted, namely, ensemble and precipitation adjustment.
The ensemble approach was effective at modulating the differences in
performance among models, and the precipitation-adjusted approach
demonstrated that the model performance for precipitation played a key role
in better simulating wet deposition. Finally, the lessons learned from the
phase III study and future perspectives for phase IV are summarized.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-20-2667-2020
DOI:
10.5194/acp-20-2667-2020-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2020
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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