Application of a global nonhydrostatic model with a stretched-grid system to regional aerosol simulations around Japan
An aerosol-coupled global nonhydrostatic model with a stretched-grid system has been developed. Circulations over the global and target domains are simulated with a single model, which includes fine meshes covering the target region to calculate meso-scale circulations. The stretched global model in...
Main Authors: | , , , , , , , , , , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2015-02-01
|
Series: | Geoscientific Model Development |
Online Access: | http://www.geosci-model-dev.net/8/235/2015/gmd-8-235-2015.pdf |
Summary: | An aerosol-coupled global nonhydrostatic model with a stretched-grid system
has been developed. Circulations over the global and target domains are
simulated with a single model, which includes fine meshes covering the target
region to calculate meso-scale circulations. The stretched global model
involves lower computational costs to simulate atmospheric aerosols with fine
horizontal resolutions compared with a global uniform nonhydrostatic model,
whereas it may require higher computational costs compared with the general
regional models, because the stretched-grid system calculates inside and
outside the target domain. As opposed to general regional models, the
stretched-grid system requires neither a nesting technique nor lateral
boundary conditions. In this study, we developed a new-type regional model
for the simulation of aerosols over Japan, especially in the Kanto areas
surrounding Tokyo, with a maximum horizontal resolution of approximately
10 km. This model usually reproduces temporal variations and their
averages of the observed weather around Japan. This model generally
reproduces monthly mean distributions of the observed sulfate and
SO<sub>2</sub> over East Asia, with high correlations (<I>R</I> > 0.6), but the
underestimation of the simulated concentrations by 40% (sulfate) and
50% (SO<sub>2</sub>). Their underestimation of the simulated sulfate and
SO<sub>2</sub> concentrations over East Asia are strongly affected by their
underestimation in China and possibly by the uncertainty of the simulated
precipitation around Japan. In the Kanto area, this model succeeds in
simulating the wind patterns and the diurnal transitions around the center of
the Kanto area, although it is inadequate to simulate the wind patterns and
the diurnal transitions at some sites located at the edge of the Kanto area
and surrounded on three sides by mountains, e.g., Maebashi, mainly due to the
insufficient horizontal resolution. This model also generally reproduces both
diurnal and synoptic variations of the observed and/or a regional
aerosol-transport model, WRF-CMAQ, simulated EC, sulfate, and SO<sub>2</sub>
concentrations in the Kanto area, especially with their high correlation (<I>R</I>
> 0.5) at Komae/Tokyo. Although the aerosol module used in this study is
relatively simplified compared to the general regional aerosol models, this
study reveals that our proposed model with the stretched-grid system can be
applicable for the regional aerosol simulation. |
---|---|
ISSN: | 1991-959X 1991-9603 |