# Presentation: 224405

## TF HTAP Multi-model Estimates of Intercontinental Source-Receptor Relationships for Ozone Pollution

** **
**TF HTAP Multi-model Estimates of Intercontinental Source-Receptor Relationships for Ozone Pollution**

- TF HTAP Workshop, Washington, DC, June 10, 2008

**Arlene M. Fiore**
**(arlene.fiore@noaa.gov)**

- F. Dentener, O. Wild, C. Cuvelier, M. Schultz, C. Textor, M. Schulz, C. Atherton, D. Bergmann, I. Bey, G. Carmichael, R. Doherty, B. Duncan, G. Faluvegi, G. Folberth, M. Garcia Vivanco, M. Gauss, S. Gong, D. Hauglustaine, P. Hess, T. Holloway, L. Horowitz, I. Isaksen, D. Jacob, J. Jonson, J. Kaminski, T. Keating, A. Lupu, I. MacKenzie, E. Marmer, V. Montanaro, R. Park, K. Pringle, J. Pyle, M. Sanderson, S. Schroeder, D. Shindell, D. Stevenson, S. Szopa, R. Van Dingenen, P. Wind, G. Wojcik, S. Wu, G. Zeng, A. Zuber

## Wide range in prior estimates of intercontinentalsurface ozone source-receptor (S-R) relationships

**Wide range in prior estimates of intercontinental****surface ozone source-receptor (S-R) relationships**

**Receptor = Asia**

**Receptor = Europe**

**Receptor = North America**

**Assessment hindered by different:**
**methods **
**regional definitions**
**reported metrics**
**years (meteorology) **
**Adopt a multi-model approach**
**Consistency across models**
**Examine all seasons**

- Estimates are from studies cited in TF HTAP [2007] Ch5, plus new work [*Holloway et al*., 2008; *Duncan et al*., 2008; *Lin et al*., 2008]

- A.M. Fiore

**Notes:**
Little boxes – just one or two studies

## Objective: Quantify & assess uncertainties in 	        N. mid-latitude S-R relationships for ozone

**Objective: Quantify & assess uncertainties in ****	****        N. mid-latitude S-R relationships for ozone**

**BASE SIMULATION (21 models):**** **
**	******** ****horizontal resolution of 5****°****x5° or finer**
**	******** ****2001 meteorology**
**	******** ****each group’s best estimate for 2001 emissions**
**	******** ****methane set to 1760 ppb**
**SENSITIVITY SIMULATIONS (13-18 models):**
**	******** ****-20% regional anthrop. NO****x****, CO, NMVOC emissions,**
**    ****	****	****individually + all together (=16 simulations)**
**	******** ****-20% global methane (to 1408 ppb)**

**TF HTAP REGIONS**

- A.M. Fiore

## Large inter-model range; multi-model mean generally captures observed monthly mean surface O3 

**Large inter-model range; multi-model mean generally captures observed monthly mean surface O****3**** **

**Mediterranean**

**Central Europe < 1km**

**Central Europe > 1km**

**NE USA**

**SW USA**

**SE USA**

**Japan**

**Mountainous W USA**

**Great Lakes USA**

**Surface Ozone (ppb)**

- A.M. Fiore

## North America as a receptor of ozone pollution: Annual mean foreign vs. domestic influences

**(1.64)**

**Full range of **
**15 individual **
**models**

**Annual mean surface O****3**** decrease from **
**-20% NOx+CO+NMVOC regional anthrop. emissions**

**“****Sum 3 foreign”**

**“****domestic”**

**ppbv**

**“****import sensitivity”**

- A.M. Fiore

## North America as a receptor of ozone pollution: Seasonality of response to -20% foreign anthrop. emissions

**SA**

**EU**

**EA**

**SUM OF 3 FOREIGN REGIONS**

**15- MODEL MEAN SURFACE**
**O****3**** DECREASE (PPBV)**

**Spring (fall) max due to longer O****3**** lifetime, efficient transport **
- [e.g., Wang et al., 1998; Wild and Akimoto, 2001; Stohl et al., 2002; TF HTAP 2007]

- A.M. Fiore

**Notes:**
Springtime: 10 models equivalent; 4 EA 30-55% > EU; annual mean that is 8 predict equivalent & 6 suggest 25-50% greater from EA

## North America as a receptor of ozone pollution:Seasonality of response to -20% foreign anthrop. emissions 

**CO**

**NO****x**

**NMVOC**

**NO****x****+NMVOC+CO**

** ****MODEL ENSEMBLE MEAN SURFACE**
**O****3**** DECREASE (PPBV)**

**Wide range in EU anthrop. NMVOC inventories **
****** ****large uncertainty in the estimated response of NA O****3**

- A.M. Fiore

## North America as a receptor of ozone pollution: Seasonality in “import sensitivity” 

**North America as a receptor of ozone pollution: ****Seasonality in “import sensitivity” **

**Surface O****3**** response to -20% domestic**
**(NA NOx+NMVOC+CO) anthrop. emis.**

**PPB**
**RATIO**

- Response to -20%
- Foreign > Domestic
- (winter)

- A.M. Fiore

**Notes:**
Conclude that response to foreign, although 10ths of ppb is not trivial when compared with response to equivalent % reductions in domestic anthrop. Emissions... Point out “shoulder” = “high-transport” seasons, where future growth in foreign emissions may extend season of poor air quality

## Estimates of S-R relationships for surface O3 pollution

**Source region:**

**sum of 3 foreign regions**

**Receptor region:     **NA**  ****        ****EU****           ****E Asia****       ****S Asia****  **

**Full range of **
**15 individual **
**models**

**Annual mean surface O****3**** decrease from **
**-20% NOx+CO+NMVOC regional anthrop. emissions**

**Import sensitivity:    **  0.45             **0.75                 0.65                 0.45**

- A.M. Fiore

**Notes:**
NA = same from previous slide; now same analysis for the 3 foreign regions... define import sensitivities, then focusing on NA influence elsewhere... 
Finish: Black bars = sum of 3 foreign regions – finish by comparing this response to “conventional” precursors to the response to CH4... 

## Surface O3 response to decreases in foreign anthropogenic emissions of O3 precursors

**Surface O****3**** response to decreases in foreign anthropogenic emissions of O****3**** precursors**

**Source region:   SUM3   ****NA ****  ****EA****   ****EU****   ****SA**

**EU receptor**

**EA receptor**

**SA receptor**

- Surface O3 decrease (ppb)

- A.M. Fiore

**Notes:**
Mention: SA emis smallest in annual mean / springtime; EA spring, most models EU/NA > SA; SA: many models annual mean equivalent responses to at least 2 regions

## Monthly mean import sensitivities

- A.M. Fiore

## Range of estimated S-R relationships narrows from that in the literature with consistently applied HTAP approach 

**Range of estimated S-R relationships narrows from that in the literature with consistently applied HTAP approach **

**Receptor = EA**

**Receptor = EU**

- Assume linearity, scale response to -20% to 100% to estimate total contribution

**Receptor = NA**

- A.M. Fiore

## Apply S-R relationships to address hypothesis of rising background O3 driven by increasing Asian emissions

**Assuming +10% yr****-1 ****Asian emissions, **
**our results imply an O****3**** increase **
**over NA and EU of at most 0.15 ppb yr****-1**
**OUR CAVEATS:**
**-- assumes SA+EA, + other emissions follow NO****x**
**-- continental-avg vs. “west coast” obs **

- A.M. Fiore

## Surface ozone response to -20% global [CH4]:similar decrease over all regions 

**Full range of **
**18 models**

**ppb**

**EU              NA            E Asia        S Asia  **

**1 ppbv O****3**** decrease **
**over all regions **
- [Dentener et al.,2005;
- Fiore et al., 2002, 2008;
- West et al., 2007]

**Estimate O****3**** response to -20% regional CH****4 ****anthrop. emissions to**
**        ****compare with O****3**** response to**** NOx+NMVOC+CO:**
** ****-20% global [CH****4****]  ****≈**** -25% global anthrop. CH****4**** emissions **
** ****Anthrop. CH****4**** emis. inventory **[Olivier et al., 2005]** for regional emissions **
** ****Scale O****3**** response (linear with anthrop. CH****4**** emissions **[Fiore et al., 2008]**)**

- A.M. Fiore

**Notes:**
20% global CH4  -25% global anthrop. Emissions (accounting for feedback of methane on its own lifetime (F = 1.33)+ anthrop = 60% total CH4 emissions [IPCC 2007])

## Comparable annual mean surface O3 response to -20% foreign anthropogenic emissions of CH4 vs. NOx+NMVOC+CO

**ppb**

- (Uses CH4 simulation + anthrop. CH4 emission inventory [*Olivier et al*., 2005]
- to estimate O3 response to -20% regional anthrop. CH4 emissions)

**Sum of annual mean ozone decreases from 20% reductions of anthropogenic emissions in the 3 foreign regions**

**Receptor:   ****	****   NA                 EU              E Asia           S Asia  **

- A.M. Fiore

## Areas needing additional analysis (*studies underway)

- Relevance to air quality objectives*
- Variability within HTAP regions
- Assess simulation of metrics used to determine compliance
- Scalability of results (non-linearities)*
- Process-based evaluation*
- Relative contributions from transport, emissions, chemistry to uncertainties
- Summertime bias (EUS*)
- NMVOC inventories / reactivity mix (esp. EU)
- Changes in SR relationships
- Interannual
- Future (emissions, climate)

- A.M. Fiore

**Notes:**
Not exhaustive! Regional models – e.g. Jerry Lin’s poster; scalability – Wild/Wu; process-based –ES3 (Bey / Evans) – TP (Schultz); 

## Simulated vs. observed DAYS>60 over Europe

-   observed mean (across sites)

-  model ens. mean

-  model ens. median

-  individual models

******Model ensemble mean close to observed**
**except for low bias at high-altitude sites**
** **
******Ensemble mean results consistent with **
**evaluation for monthly mean results.**

**EMEP sites**

- A.M. Fiore

##  Conclusions: Intercontinental S-R Relationships for O3

-    Benchmark for future: Robust estimates + key areas of uncertainty
- Robust: NAEU largest; SAothers smallest;
-          NA/EU often > SA/EA on each other
- Uncertainty on relative roles of EU/EA  NA; NOx/NMVOC NA
- Model ensemble mean overestimate vs. obs in summer EUS and Japan
-    Estimated “import sensitivities”
- Over EA/NA/EU, response to “ALL” foreign vs. domestic anthrop. emis.
-      = 0.6-1.1 during month of max response to foreign emissions
- 	 = 0.2-0.3 during month of max response to domestic emissions
- Over SA =0.45 (max response to foreign+domestic); little seasonality
-    Reported emis. trends + SR estimates  low end of observed surface O3 trends
-    Reducing equivalent % of CH4 yields an O3 decrease similar to that achieved
-      with NOx+NMVOC+CO over foreign regions (0.4-0.6 ppb for 20% reductions)

- A.M. Fiore