# Presentation: 389004

## THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL: Model Configuration and Enhancements for 2006 Air Quality Forecasting

**Rohit Mathur, Jonathan Pleim, Kenneth Schere, George Pouliot, Jeffrey Young, Tanya Otte**
- Atmospheric Sciences Modeling Division
- ARL/NOAA
- NERL/U.S. EPA
**Hsin-Mu Lin, Daiwen Kang, Daniel Tong, Shaocai Yu, **
- Science and Technology Corporation

## Acknowledgements

**Acknowledgements**

-  Jeff McQueen, Pius Lee, Marina Tsidulko
-  Paula Davidson

## WRF-NMM-CMAQ AQF System

**Verification Tools**

**CMAQ**

**WRF Post**

**PRDGEN**

**AQF Post**

- Vertical interpolation

- Horizontal interpolation to Lambert grid

- CMAQ-ready meteorology and emissions

- Gridded ozone files for users

- Chemistry/Transport/Deposition model

- NAM Meteorology model

- Performance feedback for users/developers

**PREMAQ**

**Meteorological**
** ****Observations**

**     ****Emission**
**Inventory Data**

**WRF-NMM**

**     ****Air Quality **
**Observations**

**WRF-NMM-CMAQ AQF System**

## CMAQ Modeling Domains

- 268 grid cells

- 259
- grid
- cells

**East “3x” Domain**

**CMAQ Modeling Domains**

- Ozone forecasts both domains

- Experimental PM forecasts on 5x

- 12 km resolution

**CONUS “5x” Domain**
**      ****Experimental**

- 265
- grid
- cells

- 442 grid cells

## Emission Processing

- Emission Processing is a component of PREMAQ  (pre-processor to CMAQ)
- Point Source and Biogenic Source processing from SMOKE
- Area Sources (no meteorological modulation) computed in SMOKE outside of PREMAQ
- Mobile Sources (nonlinear least squares approximation to SMOKE/Mobile6)

## Area and Biogenic Sources

- Area Sources: Computed outside of PREMAQ
- 2001 NEI version 3 inventory used. (CAIR) No changes made to inventory.
- Replaced year specific with average (1996-2002) estimates for fires
- Biogenic Sources: BEIS3.13 included directly into PREMAQ.
- Canadian Inventory: 1995 used (includes all provinces)
- Mexican Inventory: BRAVO 1999 used for point sources

## Mobile Sources

- SMOKE/MOBILE6 not efficient for real-time forecasting
- SMOKE/MOBILE6 used to create retrospective emissions for AQF grid
- 2006 (projected from 2001) VMT data used for input to Mobile 6
- 2006 Vehicle Fleet used for input to Mobile 6
- For 13 counties in Metropolitan Atlanta area, VMT based on 2005 run of a travel demand model and Mobile6 *inputs from Georgia DNR*

## Mobile Sources

- Regression applied at each grid cell at each hour of the week for each species to create temperature/emission relationship
- Mobile Source emissions calculated in real-time using this derived temperature/emission relationship

-  For California used 2001 mobile estimates from
-    CARB

## NE Domain Mobile6 vs. Regression: NOx 

**Monday**

**Saturday**

## NE Domain Mobile6 vs. Regression: VOC 

**Monday**

**Saturday**

## Point Sources

- 2004 Continuous Emissions Monitoring for NOx and SO2
- Monthly temporal profiles on a state-by-state basis  derived from 2004 CEM
- For other pollutants and non-EGU: 2001 NEIv3
- Georgia non-EGU based on 2002 inventory from GADNR
- Modified EGU NOx emissions using DOE’s Annual Energy Outlook (Jan. 2006)
- Calculated 2006/2004 NOx and SO2 annual emission ratios on a regional basis (from DOE data)
*Exception California*

- 1.03

- 1.01

- 1.12

**1.0**

- 0.74

- 0.95

- 1.64

- 1.20

- 1.11

- 0.98

- 1.02

- 1.56

- 0.84

**EGU NO****X**** adjustments 2006/2004 by region**

- Source: Department of Energy Annual Energy Outlook 2006
-                 *http://www.eia.doe.gov/oiaf/aeo/index.html*

*DOE/AOE estimated*
*an increase by factor of 8*

## CMAQ Configuration

**Advection**
- Horizontal: *Piecewise Parabolic Method*
- Vertical: *Upstream with rediagnosed vertical velocity to satisfy mass conservation*
**Turbulent Mixing**
- K-theory; PBL height from WRF-NMM
- Minimum value of Kz allowed to vary spatially depending on urban fraction (*f**urban*)
- Kz = 0.1 m2/s, *f**urban* = 0
- Kz = 2.0 m2/s, *f**urban* = 1
- allows min. Kz in rural areas to fall off to lower values than urban regions during night-time
- prevents precursor concentrations (e.g., CO, NOx) in urban areas from becoming too large at night; reduced mixing intensity) in non-urban areas results in increased night-time O3 titration

## CMAQ Configuration (contd.)

**Gas phase chemistry**
*CB4 mechanism with EBI solver*
- Below cloud attenuation based on ratio of radiation reaching the surface to its clear-sky value
- Closer linkage with the NAM fields
**Cloud Processes**
- Mixing and aqueous chemistry
- Scavenging and wet deposition
- Sub-grid scheme based on modifications to RADM formulation; “switch-off” entrainment from above clouds
**Used in Eastern U.S. (3x) domain**
- “In-cloud” mixing based on the Asymmetric Convective Mixing (ACM) model (Pleim and Chang, 1992, *JGR*)
**Used in Continental U.S. (5x) domain**

## CMAQ Configuration (contd.)

**Deposition**
- Dry : M3dry modified to use WRF land surface parameters
- Changes in WRF-LSM impact Vdo3 (relative to Eta)
- Persistent sink for O3 – can impact predicted O3

**ETA**

**WRF**

**ETA**

**WRF**

**O****3**** Deposition Velocity**

**Stomatal Conductance**

## CMAQ Configuration: Aerosols

- SVOCs

- Na+, Cl-, SO42-
- Soil, Other

**COARSE MODE**

**2 FINE MODES**

-  Trimodal size distribution
-  Aitken (0-0.1 μm), Accumulation(0.1-2.5 μm),
-   and Coarse
-  Gas/particle interactions treated   for fine modes only – ISORROPIA   instantaneous equilibrium
-  Fine-modes coagulate
-  Coarse mode, fine EC (**black**) &  other fine PM (**brown**) are inert

***CMAQ Configuration: Aerosols***

***Binkowski and Roselle, JGR, 2002***

## Structural Enhancements

- Included layer dependent advection time-step calculation
- Improves model efficiency
- Coupling between WRF-NMM and CMAQ
- “**Loose-coupling**” (*used in Operational 3X*)
- Similar to previous Eta-CMAQ linkage
- WRF-NMM and CMAQ coordinate and grid structures are different. Interpolation of meteorological inputs to the CMAQ grid and coordinate
- “**Tight-coupling**” (*implemented in Experimental 5X*)
- Step 1: Coupling in the vertical implemented this summer
- CMAQ calculations on the same vertical coordinate as WRF-NMM
- Step 2: Modifications to CMAQ to facilitate *calculations on native WRF-NMM horizontal grid*
- Stay tuned

## WRF-NMM Hybrid Vertical Coordinate System“Tightly Coupled”

**WRF-NMM Hybrid Vertical Coordinate System****“Tightly Coupled”**

##                     Tightly Coupled System

- Jacobian across the interface

***Jacobian: encapsulates coordinate transformations ***
***between physical and computational space***

-                     **Tightly Coupled System**
- Conversion to use WRF-NMM vertical coordinate in PREMAQ and CMAQ

## Comparison of Experimental and Operational Forecasts

**Comparison of Experimental and Operational Forecasts**
-                                         Mean over sites within Operational 3x Domain

- 5X under-predictions at peak values

## Comparison of Experimental and Operational Forecasts

- Operational (3X)

- Developmental (5X)

- 5X vs. 3X: Regionally lower O3; under-prediction of peak values

## Diagnosing the low-bias in Experimental 5X Runs

**Black** (Loose), **Red** (Tight w/ISOP error), **Green** (Corrected Tight)

**California Sub-domain average time series: July 18-19, 2006**

**Isoprene**

**NTR**

**Ozone**

**NTR**: Inert organic nitrate in CBM-IV

## Correcting the low-bias in Experimental 5X Runs

- Loose

- Old Tight

- IsopreneFix Tight

**Max.-8hr  O****3****:  7/19/06**

## Correcting the low-bias in Experimental 5X Runs

**Max. 8 O3**
**   ****7/19/06**

- Loose

- Old Tight

- Isoprene Fix Tight

## Improvements from Tight Coupling

**Improvements from Tight Coupling**
**           **Mass-consistent advection

**Vertical Velocity Cross-sections**

- Tight coupling helps reproduce WRF-NMM vertical velocity fields with higher fidelity
- Note: Large discrepancies at model top in loose-coupling

## Lateral Boundary Condition Specification

- A key uncertainty in long term modeling over limited area domains
*Determines “model background”*
**Approach in Operational Runs**: Combination of
**Static default profiles**
- “Clean” tropospheric background values
**Top most CMAQ-layer**: O3 profiles from NCEP’s Global Forecast System (GFS) model
- O3 is a 3-d prognostic variable
- Initialized with Solar Backscatter Ultra-Violet (SBUV-2) satellite observations
**Approach in Experimental Runs**
**Static default profiles**
**Added diagnostic tracers** to quantify “model background” O3
-  Tracked impact of lateral boundary conditions (surface-3km and 3km-model top)

## Modeled surface-level “background” O3

**Modeled surface-level “background” O****3**

- Average from July 1-August 22, 2006

- Background O3 distributions are spatially heterogeneous

## Components of modeled surface-level “background” O3

**Components of modeled surface-level “background” O****3**

- “Boundary Layer”
-    Surface – 3km

- “Free Troposphere”
-    3km – Model top

## Components Modeled “background” O3: Relative Contributions/Fraction

- “Boundary Layer”
-    Surface – 3km

- “Free Troposphere”
-    3km – Model top

##  Performance Summary for PM2.5 over a year: 2005

- Warm-season Under-prediction

- Cool-season Over-prediction

** ****Performance Summary for PM****2.5**** over a year: 2005**

- Captures day-to-
- day variability

##  Performance Summary over a year: 2005

** ****Performance Summary over a year: 2005**

- Larger errors at higher concentrations

- Winter high bias
- Possible measurement bias
- Role of dynamics
- Unspeciated “Other” PM is biased high

##   Model Performance Characteristics: Winter 2005 

**5    10   15   20   25   30   35**

**μ****g/m****3**

**  ****Model Performance Characteristics: **_**Winter**_** 2005 **
**          ****Model and Observed Daily Average Surface PM****2.5**

- Capture hot-spots, tendency to over-predict
-  ***possible role of mixing; K******zmin****** and/or PBL height ?***

**Notes:**
February 1-6: Evolution of model and observed pm surface distributions

## PM2.5 Compositional Characteristics

**PM****2.5**** Compositional Characteristics**
**            ****STN Measurements**

**Summer 2004**

**Winter 2005**

-  Reasonable representation of Inorganic
-   compositional characteristics
-  *Sulfate fraction over-predicted*
* **Organic fraction under-predicted*

-  Nitrate is a bigger player
-  Larger OC fraction
-  under-predictions at lower
-   concentrations

## Specification of “Real Time” Emissions

- June 24, 2005: Daily Avg. PM2.5

- Without Fires

- With Fires

- Difference

**Specification of “Real Time” Emissions**
**Testing HMS-HYSPLIT fire emissions algorithm**

- Cave Creek Complex fire began as two lightning-sparked fires on June 21, 2005. Became
- second largest fire in Arizona history.

## Specification of “Real Time” Emissions

**Fire plume signatures: June 24, 2005**

**Specification of “Real Time” Emissions**
- Testing HMS-HYSPLIT fire emissions algorithm

- June 21-26, 2005 Daily Avg.: Southern NV sites

- Real-time specification of fire emissions improves
- PM forecast skill

- June 24, 2005

## Summary/Looking Ahead

- AQF system transitioned to WRF-NMM
- Growing pains with a new and evolving modeling system
- WRF-NMM based dry-deposition velocities are higher than those derived from Eta
- Persistent sink- can systematically impact predicted O3
- Implemented the first step in tighter coupling between CMAQ and WRF-NMM computational grids
- CMAQ calculations using the WRF-NMM vertical coordinate
- Modifications to CMAQ to use the E-grid and rotated lat/lon coordinate underway
- Under-predictions for surface O3 in experimental predictions were found to arise from error in isoprene emission calculations
- Un-initialized lat/lon fields

## Summary/Looking Ahead

- Initial analysis of boundary tracers indicate that *modeled O**3** background values are strongly influenced by free tropospheric LBC* values
- Locations at which O3 is over-predicted generally also correspond to high background but low observed values
- Rigorous analysis of developmental PM simulations underway
- Seasonal trends/biases similar to hind-cast CMAQ applications
- Speciated PM verifications with surface network (STN, CASTNet, IMPROVE, SEARCH) and aloft (ICARTT) data
- Initial testing of a methodology for specifying “real-time” fire emissions tested
- Initial results are encouraging