Regional chEmical trAnsport Model(REAM)

Yuzhong Zhang, Yuhang Wang, Charles Smeltzer, Dasa Gu, Zhen Liu

Yuzhong.zhang@eas.gatech.edu

1. REAM Modeling Setup and Specification2. Characterization of air pollution and emissions in China3. Pollutant distribution and lightning NOx study in USA4. Comparing with campaigns and monitoring5. HTAP2 preliminary results

REAM specification

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O3-NOx-VOCs-Halogen photochemistry

Dry/wet deposition

Meteorological fields

3-D advection

Emission inventory

BC: GEOS-Chem

Met: WRF

Biogenic: MEGAN

Vertical: 30 layers

Horizontal: 4km-36km

Biogenic emissions

Soil, lightning emissionsInitial, boundary condition

Vertical turbulent diffusion

Convective transport

REAM specification

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Dimension 0‐D 1‐D 3‐D

Resolution 4km 36km 200m*

Functionality CTM inversion

Cloud‐resolvingTracer model

REAM is a research model, providing flexibility and functionality for varied research objectives

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Study China air pollution

Liu et al., 2010; Liu et al., 2012

CARE Beijing 2007 campaign

0‐D 1‐D

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Height

Stability

Deep>1km

Medium0.5‐1km

Shallow<0.5km 

Turbulent (<0.1K/km) 40 ‐ ‐Neutral (0.1‐1K/km) 123 24 ‐Stable (>1K/km) ‐ 7 12

Vertical distribution of pollutants

DISCOVER-AQ 2011 Baltimore

Zhang et al., in prep

1‐D

Inversed NOx emission trend in China

Gu et al., 2013; Gu et al., 2014Chemical nonlinearity

Increase of emissions overall

Decrease or flat emissions in the developed cities

3‐D

Inversion

Missing source of glyoxal using inversion

3‐D

Inversion

Missing glyoxal attributed to underestimation of aromatic emissions

Liu et al., 2012

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Lightning NOx emissions

Smeltzer et al., in prep

3‐D

Cloudresolving

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Trace NOx contributions from each grid

3‐D

Tagged‐Tracer

Each box has it's own NO2 tracer throughout the whole domain

• US domain• 36km• Gas phase• Base simulation

– Station surface– Station profile

• Fixed BC simulation

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HTAP status 

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DISCOVER‐AQ vertical profiles

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DISCOVER‐AQ column correlations

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Observation Model Bias Correlation r MAD CV ppbv ppbv ppbv ppbv Whole 48.9 48.1 -0.8 0.66 7.0 14% SE US 48.5 50.7 2.2 0.73 5.9 12%

EPA monitoring sites

3‐D

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EPA monitoring sites

October, 2010

3‐D

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Ozonesonde in the western US

Monthly mean BC Hourly updating BC ozonesonde

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Calnex aircraft measurements

Questions?

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