# Presentation: 200368

## WRF/Chem Regional Modeling of the Mid-Atlantic: Comparison with Aura and Ground Based Measurements

- Elena Yegorova, Dale Allen, Christopher Loughner, and Russell Dickerson of the University of Maryland
- Kenneth Pickering of NASA-GSFC

## Goals of today’s talk 

- Simulate a Mid-Atlantic (U.S.) pollution event using a regional air quality model.
- Compare model-calc sfc layer 8-hr max ozone to AIRNOW observations.
- Compare model-calc and satellite-retrieved tropospheric ozone columns.
- Obtain insight into the capabilities of OMI and TES to detect air pollution on the urban scale.
- What event?
- July 9-11, 2007 pollution event
- What model?
- On-line Weather Research and Forecasting model with integrated chemistry (WRF-Chem).

## Baltimore, MD visibility 

- Baltimore, MD visibility
- during a clear day

- Baltimore, MD visibility
- At 6:45 PM July 9, 2007

- Images obtained from the U.S. Air
- Quality Smog Blog
- (_[http://](http://alg.umbc.edu/usaq/)__[alg.umbc.edu/usaq](http://alg.umbc.edu/usaq/)_).

- Air quality on July 9, 2007 was very bad in the Mid-Atlantic.
- 8-hr max O3 of 131 ppbv within Baltimore NAA

## WRF/Chem Configuration

| Atmospheric Processes | WRF/Chem |
| --- | --- |
| Radiation | LW: RRTM
SW: Goddard |
| Surface Layer | Monin-Obukhov |
| Land Surface Model | Noah |
| Boundary Layer | YSU |
| Cumulus | Grell |
| Microphysics | Lin et al. |
| Gas-phase chemistry | RADM2 |
| Aerosol chemistry | MADE/SORGAM |
| Photolysis | Fast J |

- Domain: Eastern U.S.
- 12 km hor res, 23 vertical layers
- Meteorology driven by the North American Mesoscale (NAM) model
- Emissions:
- Points sources from July 2007 CEMS data.
- Area sources from 2002 U.S. inventory used in SIP modeling
- Emissions processed using SMOKE modeling system
- Default (clean) chemical BC and IC are assumed (00 UT 6 Jul 2007)
- No lightning NOx or stratospheric chemistry

## TES and OMI Products

- TES:
- Level 2 Nadir Step & Stare Special Observations on July 9, 2007
- OMI-MLS global, daily tropospheric column product:
- OMI total column minus stratospheric column from the Microwave Limb Sounder (MLS)  (Lapse rate tropopause product of M.Schoeberl).

## Build-up to July 9, 2007 Air Pollution Episode

- Spatial pattern reasonable outside of Ohio River Valley. High-bias present

## WRF/Chem, OMI, and TES Tropospheric Column Ozone

- WRF/Chem, OMI, and TES Tropospheric Column Ozone

- Spatial pattern reasonable
- TES > WRF-Chem > OMI/MLS
- Note anomalous peak in TES column over northeastern New York state

**Notes:**
Click on 20070709 Plot to Zoom In. To get back to this slide, click the enlarged image.

## SE part of TES track (outflow region)   NW part of TES track (NE/Canada)

## SE part of TES track (outflow region)

- NW part of TES track (New England/Canada)

- A priori trpp lower?

## Preliminary Conclusions

- Spatial pattern of July 9-11 air quality event is captured (outside of Ohio River Valley) by WRF.  Model has high-bias at surface.
- For this particular TES flight track,
- TES tropospheric O3 column > WRF column > OMI/MLS column
- Low-bias of OMI/MLS column over New England/Canada may be due to overestimation of stratospheric MLS column (difference between *a priori* and *a posteriori* upper trop TES col suggests higher than normal tropp on this date)
- WRF-calc and satellite-observed tropospheric columns are greater in pollutant outflow region (over ocean) than over NE/Canada.  Contrast of retrieved TES columns > Contrast of *a priori* TES columns.
- Mean TES profiles show little vertical structure. However, anomalous (mostly boundary layer) peak is seen in TES column near Lake Champlain. Model shows small peak in this region.

- ***Acknowledgements**: Gregory Osterman, Mark Schoeberl, Dylan Jones, George Grell, and Steven Peckham

## This study is a work in progress.  Possible next steps include: 

- Compare with July 9 ozonesonde from Beltsville, MD
- Nested 36/12 km simulation of event with climatological BC/IC from GMI model
- Investigate sensitivity of 8-hr max ozone to convective parameterization and chemical mechanism
- Compare WRF-calc and satellite-observed HCHO and NO2 columns
- Apply averaging kernel to model before comparing to OMI measurements.
- Compare WRF-calc PM2.5 to measurements
- Other?