1. Off-line 3DVAR NOx emission constraints
TEMPO Ozone OSSE and
Off-line 3DVAR NOx emission constraints
Brad Pierce1, Vijay Natraj2, Allen Lenzen1, Susan Kulawik3, Helen Worden4, Xiong Liu5, Mike Newchurch6
1- Space Science and Engineering Center, University of Wisconsin-Madison
2- Jet Propulsion Laboratory, California Institute of Technology
3- Bay Area Environmental Research Institute
4- National Center for Atmospheric Research
5- Harvard-Smithsonian Center for Astrophysics
6- University of Alabama, Huntsville

2. TEMPO Ozone OSSE
Assess the impact of assimilating hourly, geostationary UV, UV-VIS, and UV-VIS-TIR ozone profile retrievals within a realistic OSSE environment
Utilize independent modeling systems for generation of Nature atmosphere and conducting assimilation impact experiments
Account for realistic atmospheric variability, which requires evaluation of the nature runs with respect to observations
Include realistic variability in the synthetic radiances, which requires using realistic albedos and emissivities
Include realistic sensitivities, which requires generation of averaging kernels (AK) for each retrieval for use in assimilation studies

3. Flow Chart

4. 12km Regional O3 OSSE Study – July 2011
Data Assimilation
WRF-CHEM/GSI (3D-VAR)
12km Regional O3 OSSE Study – July 2011
Control
Synthetic OMI (using retrieval efficiency factors and apriori)
Multiple Regression GEOCAPE UV-VIS-TIR synthetic retrievals
Multiple Regression GEOCAPE UV-VIS synthetic retrievals
Multiple Regression GEOCAPE UV synthetic retrievals
All GEOCAPE experiments include:
1 hour cycling
Inflation of background error covariances near surface
Application of tangent linear observation operator (AK) in GSI enter loop
Results compared to nature run integrated over atmospheric layers and at AIRNow surface sites

5. Impact of Assimilation: sfc-6km Results
Assimilation of OMI synthetic column ozone retrievals has very little impact on Sfc-6km ozone except for increase in bias. GEOCAPE results show systematic and significant increase in correlations and reductions in rms errors and biases when UV, UVVIS, and UVVISTIR are assimilated, respectively. All GEOCAPE results are improvements over control or OMI.
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6. Impact of UVVIS Assimilation: Urban Sites
Control
Nature
July 2011 Mean Diurnal Cycle
UVVIS assimilation increases correlation by 5%, reduces bias by 7%, and reduces rms error by 6% at Urban sites
nature vs control and UV-VIS-TIR assimilation for Urban sites (Diurnal standard deviation > 20ppbv)
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7. Impact of UVVISTIR Assimilation: Urban Sites
Control
Nature
July 2011 Mean Diurnal Cycle
UVVISTIR assimilation increases correlation by 9%, reduces bias by 50%, and reduces rms error by 14% at Urban sites
nature vs control and UV-VIS-TIR assimilation for Urban sites (Diurnal standard deviation >20ppbv)
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8. NO2 OSSE Flow Chart VLIDORT (high spectral resolution VIS 400-490nm)
Full Optimal Estimation Retrievals
(VIS nm)
GOES Sounder Cloud Cleared Retrievals (VIS)
WRF-Chem First Guess (NO2, P)
WRF-Chem Analysis
(NO2, P)
There are three major components of the OSSE framework: Nature run (teal), Radiative Transfer/Retrieval System (purple), and Analysis System (orange).
We then used observed GOES East and West Sounder cloud masks to identify clear retrievals, these are fed into the WRF-Chem/GSI regional assimilation system
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9. Tropospheric NO2 Column Results
Optimal Estimation Column NO2 Retrievals
(VIS nm)
20Z July 18, 2011
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10. 12km Regional NO2 OSSE Study – July 2011
Data Assimilation
WRF-CHEM/GSI (3D-VAR)
12km Regional NO2 OSSE Study – July 2011
Control
Synthetic OMI (using retrieval efficiency factors and apriori)
Synthetic TEMPO (using OE averaging kernels and apriori)
NO2 analysis increments are used for off-line adjustments of WRF-Chem NOx emissions
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11. WRF-Chem/GSI NOx emission adjustment experiments
Calculate monthly mean NO2 Jacobian (β) from a 15% NOX emission reduction perturbation experiment following Lamsal et al. 2011
Calculate monthly mean NO2 analysis increment using WRF-Chem/GSI OMI NO2 assimilation
Adjust 2011 NEI NOx emissions using Jacobian and analysis increment
Lamsal, L. N., et al. (2011), Application of satellite observations for timely updates to global anthropogenic NOx emission inventories, Geophys. Res. Lett., 38, L05810, doi: /2010GL

12. WRF-Chem OMI Based NOx Emission Adjustment
OMI based emission adjustment is 2-4% of NOx emissions (consistent with assimilation of actual OMI NO2)

13. WRF-Chem TEMPO Based NOx Emission Adjustment
TEMPO based emission adjustment is 20-40% of NOx emissions
Note change in scale!

14. WRF-Chem TEMPO NO2 DA Surface Ozone response
Control
Adjusted Emissions
Localized ppbv changes in surface ozone due to changes in NOx emissions
21Z July 04, 2011

15. OSSE Impact of TEMPO NOx emission Adjustment: O3 Urban AirNow Sites
ASSIM
Control
Nature
No significant change in diurnal behavior of surface ozone
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16. Conclusions
The Ozone OSSE demonstrates systematic and significant increase in lower to mid tropospheric correlations and reductions in rms errors and biases when hourly geostationary UV, UVVIS, and UVVISTIR ozone retrievals are assimilated, respectively.
Comparisons at US EPA surface monitoring sites shows that the overall positive impacts obtained with UVVISTIR retrieval assimilation relative to UVVIS are due to reductions in nighttime biases.
The NO2 OSSE demonstrates significant adjustments in apriori NOx emissions compared to OMI NO2 emission adjustments
Results show low surface ozone sensitivity to changes NOx Point and Area source emissions, possibly due to high urban NOx levels leading to VOC sensitive ozone production
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17. Extra Slides

18. TropOMI Tropospheric NO2 column Data Assimilation within NWS NAM-CMAQ
NOx emissions adjustments (DE) are constrained using OMI tropospheric NO2 column analysis increments (DW)
b accounts for the sensitivity of the NO2 column to changes in NOx emissions following Lamsal et al 2011.
Lamsal, L. N., et al. (2011), Application of satellite observations for timely updates to global anthropogenic NOx emission inventories, Geophys. Res. Lett., 38, L05810, doi: /2010GL

19. NAM-CMAQ surface ozone response to TropOMI offline NOx Tropospheric NO2 column Data Assimilation

20. Impact of TropOMI NO2 Offline emission adjustment: Urban Sites

21. Impact of TropOMI NO2 Offline emission adjustment: Urban Sites