scholarly journals Evaluating the contribution of changes in isoprene emissions to surface ozone trends over the eastern United States

2005 ◽  
Vol 110 (D12) ◽  
Author(s):  
Arlene M. Fiore
Keyword(s):  
United States ◽  
Surface Ozone ◽  
Eastern United States ◽  
Ozone Trends

scholarly journals Seasonal prediction of US summertime ozone using statistical analysis of large scale climate patterns

2017 ◽  
Vol 114 (10) ◽  
pp. 2491-2496 ◽  
Author(s):  
Lu Shen ◽  
Loretta J. Mickley
Keyword(s):  
United States ◽  
Large Scale ◽  
Surface Ozone ◽  
Tropical Atlantic ◽  
Eastern United States ◽  
Northeast Pacific ◽  
Ozone Concentrations ◽  
Climate Patterns ◽  
Ocean Atmosphere ◽  
Ozone Episodes

We develop a statistical model to predict June–July–August (JJA) daily maximum 8-h average (MDA8) ozone concentrations in the eastern United States based on large-scale climate patterns during the previous spring. We find that anomalously high JJA ozone in the East is correlated with these springtime patterns: warm tropical Atlantic and cold northeast Pacific sea surface temperatures (SSTs), as well as positive sea level pressure (SLP) anomalies over Hawaii and negative SLP anomalies over the Atlantic and North America. We then develop a linear regression model to predict JJA MDA8 ozone from 1980 to 2013, using the identified SST and SLP patterns from the previous spring. The model explains ∼45% of the variability in JJA MDA8 ozone concentrations and ∼30% variability in the number of JJA ozone episodes (>70 ppbv) when averaged over the eastern United States. This seasonal predictability results from large-scale ocean–atmosphere interactions. Warm tropical Atlantic SSTs can trigger diabatic heating in the atmosphere and influence the extratropical climate through stationary wave propagation, leading to greater subsidence, less precipitation, and higher temperatures in the East, which increases surface ozone concentrations there. Cooler SSTs in the northeast Pacific are also associated with more summertime heatwaves and high ozone in the East. On average, models participating in the Atmospheric Model Intercomparison Project fail to capture the influence of this ocean–atmosphere interaction on temperatures in the eastern United States, implying that such models would have difficulty simulating the interannual variability of surface ozone in this region.

scholarly journals Impact of lightning-NO on Eastern United States photochemistry during the summer of 2006 as determined using the CMAQ model

2011 ◽  
Vol 11 (6) ◽  
pp. 17699-17757 ◽  
Author(s):  
D. J. Allen ◽  
K. E. Pickering ◽  
R. W. Pinder ◽  
B. H. Henderson ◽  
K. W. Appel ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Wet Deposition ◽  
Surface Ozone ◽  
Convective Precipitation ◽  
Eastern United States ◽  
Ozone Monitoring Instrument ◽  
Monitoring Instrument ◽  
Ozone Monitoring ◽  
The Impact

Abstract. A lightning-nitrogen oxide (NO) algorithm is developed for the regional Community Multiscale Air Quality Model (CMAQ) and used to evaluate the impact of lightning-NO emissions (LNOx) on tropospheric photochemistry over the Eastern United States during the summer of 2006. The scheme assumes flash rates are proportional to the model convective precipitation rate but then adjusts the flash rates locally to match monthly average observations. Over the Eastern United States, LNOx is responsible for 20–25 % of the tropospheric nitrogen dioxide (NO2) column. This additional NO2 reduces the low-bias of simulated NO2 columns with respect to satellite-retrieved Dutch Ozone Monitoring Instrument NO2 (DOMINO) columns from 41 to 14 %. It also adds 10–20 ppbv to upper tropospheric ozone and 1.5–4.5 ppbv to 8-h maximum surface layer ozone, although, on average, the contribution of LNOx to surface ozone is 1–2 ppbv less on poor air quality days. Biases between modeled and satellite-retrieved tropospheric NO2 columns vary greatly between urban and rural locations. In general, CMAQ overestimates columns at urban locations and underestimates columns at rural locations. These biases are consistent with in situ measurements that also indicate that CMAQ has too much NO2 in urban regions and not enough in rural regions. However, closer analysis suggests that most of the differences between modeled and satellite-retrieved urban to rural ratios are likely a consequence of the horizontal and vertical smoothing inherent in columns retrieved by the Ozone Monitoring Instrument (OMI). Within CMAQ, LNOx increases wet deposition of nitrate by 50 % and total deposition of nitrogen by 11 %. This additional deposition reduces the magnitude of the CMAQ low-bias in nitrate wet deposition with respect to National Atmospheric Deposition monitors to near zero. In order to obtain an upper bound on the contribution of uncertainties in chemistry to upper tropospheric NOx low biases, sensitivity calculations with updated chemistry were run for the time period of the Intercontinental Chemical Transport Experiment (INTEX-A) field campaign (summer 2004). After adjusting for possible interferences in NO2 measurements and averaging over the entire campaign, these updates reduced 7–9 km biases from 32 to 17 % and 9–12 km biases from 57 to 46 %. While these changes lead to better agreement, a considerable NO2 low-bias remains in the uppermost troposphere.

scholarly journals The Response of surface ozone to climate change over the Eastern United States

2007 ◽  
Vol 7 (4) ◽  
pp. 9867-9897 ◽  
Author(s):  
P. N. Racherla ◽  
P. J. Adams
Keyword(s):  
Climate Change ◽  
United States ◽  
Surface Ozone ◽  
Future Climate ◽  
Future Climate Change ◽  
Eastern United States ◽  
Chemical Production ◽  
Annual Average ◽  
Mixing Ratios ◽  
Ozone Episodes

Abstract. We examined the response of surface ozone to future climate change over the eastern United States by performing simulations corresponding to present (1990s) and future (2050s) climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050 s decade, resulting in an increase in the global annual-average surface air temperature by 1.7°C, with a 1.4°C increase over the surface layer of the eastern United States. Present-day anthropogenic emissions and CO2/CH4 mixing ratios have been used in both simulations while climate-sensitive natural emissions were allowed to vary with the simulated climate. There is practically zero change in the spatiotemporally averaged ozone mixing ratios predicted over the eastern United States. However, the severity and frequency of ozone episodes over the eastern United States increased due to future climate change, primarily as a result of increased ozone chemical production due to increased natural isoprene emissions. The 95th percentile ozone mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range. The most substantial and statistically significant (p-value <0.05) increases in episode frequency occurred over the southeast and midatlantic United States, largely as a result of 20% higher annual-average natural isoprene emissions. Increased chemical production and shorter average lifetime are consistent features of the predicted seasonal surface ozone response, with the former's magnitude for a location largely a function of increased natural isoprene emissions, and the latter largely due to faster dry deposition removal rates. Future climate change is also predicted to lengthen the ozone season over the eastern United States to include late spring and early fall. Significant interannual variability is observed in the frequency of ozone episodes and we find that it is necessary to utilize 5 years or more of simulation data in order to separate the effects of interannual variability and climate change on ozone episodes.

scholarly journals Influence of synoptic patterns on surface ozone variability over the Eastern United States from 1980 to 2012

2015 ◽  
Vol 15 (9) ◽  
pp. 13073-13108 ◽  
Author(s):  
L. Shen ◽  
L. J. Mickley ◽  
A. P. K. Tai
Keyword(s):  
United States ◽  
Great Plains ◽  
Surface Ozone ◽  
Empirical Orthogonal Functions ◽  
Eastern United States ◽  
Orthogonal Functions ◽  
Synoptic Patterns ◽  
Weather Patterns ◽  
Time Period ◽  
Pattern Characteristic

Abstract. We investigate the effect of synoptic-scale weather patterns on observed maximum daily 8 h average (MDA8) surface ozone over the eastern United States during 1980–2012 in summer (June–August, JJA). Zonally averaged, the SD of daily MDA8 JJA ozone shows a bimodal structure, with peaks at 30–35° N and 39–43° N, identifying those regions most influenced by daily weather variability. We apply Empirical Orthogonal Functions (EOFs) to understand the causes of this structure. The first three leading EOF patterns explain 53% of the total variance in deseasonalized surface ozone, displaying (1) a widespread decrease of ozone in the eastern United States associated with southward movement of jet wind, (2) a north–south pattern linked to the Bermuda High system when its west boundary is located along the East coast, and (3) an east–west pattern characteristic of a westward extension of Bermuda High and an enhanced Great Plains low level jet (GPLLJ). The northern peak of ozone SD can be explained by polar jet activity, while the southern peak appears related to variability in the Bermuda High and GPLLJ. In the Midwest and Northeast, we find that the correlation coefficient r between detrended mean JJA MDA8 ozone and the polar jet frequency ranges between −0.76 and −0.93 over 1980–2012 depending on the time period selected, suggesting that polar jet frequency could provide a simple metric to predict ozone variability in future climate regimes. In the Southeast, the influence of the Bermuda High on mean JJA MDA8 ozone depends on the location of its west edge. For those summers when the average position of the west edge is located west of ∼ 85.4° W, a westward shift in the Bermuda High west edge increases ozone in the Southeast by ∼ 1 ppbv deg-1 in longitude. For all summers, a northward shift in the Bermuda High west edge increases ozone over the entire eastern United States by 1–2 ppbv deg-1 in latitude. None of the synoptic patterns identified in this study show a significant trend from 1980 to 2012, confirming that the observed ozone decrease over the eastern United States during this time period is mainly caused by emission controls.

scholarly journals Influence of synoptic patterns on surface ozone variability over the eastern United States from 1980 to 2012

2015 ◽  
Vol 15 (19) ◽  
pp. 10925-10938 ◽  
Author(s):  
L. Shen ◽  
L. J. Mickley ◽  
A. P. K. Tai
Keyword(s):  
United States ◽  
Atmospheric Chemistry ◽  
Surface Ozone ◽  
Empirical Orthogonal Functions ◽  
Eastern United States ◽  
Orthogonal Functions ◽  
Synoptic Patterns ◽  
Time Period ◽  
Relative Standard ◽  
The Impact

Abstract. We investigate the effect of synoptic-scale weather patterns on observed maximum daily 8-hour average (MDA8) surface ozone over the eastern United States during 1980–2012 in summer (June–August, JJA). Zonally averaged, the relative standard deviation (SD) of daily MDA8 JJA ozone shows a bimodal structure, with peaks at 28–32 and 40–45° N, and we show that those regions are most influenced by the variability in daily weather. We apply empirical orthogonal functions (EOFs) to understand the causes of this structure. The first three leading EOF patterns explain 53 % of the total variance in detrended surface ozone, displaying (1) a widespread response of ozone in the eastern United States associated with north–south movement of jet wind latitude, (2) a north–south pattern linked to the Bermuda High system when its west boundary is located along the east coast, and (3) an east–west pattern characteristic of a westward extension of the Bermuda High and an enhanced Great Plains low level jet (GPLLJ). The northern peak of ozone relative SD can be explained by polar jet activity, while the southern peak appears related to variability in the Bermuda High and GPLLJ. We define a new metric polar jet frequency as the total number of days the jet traverses the Midwest and northeast each summer. In the Midwest and northeast, we find that the correlation coefficient r between detrended mean JJA MDA8 ozone and the polar jet frequency ranges between −0.76 and −0.93 over 1980–2012 depending on the time period selected, suggesting that polar jet frequency could provide a simple metric to predict ozone variability in future climate regimes. In the southeast, the influence of the Bermuda High on mean JJA MDA8 ozone depends on the location of its west edge. For those summers when the average position of the west edge is located west of ~ 85.4° W, a westward shift in the Bermuda High west edge increases ozone in the southeast by ~ 1 ppbv deg−1 in longitude. For all summers, a northward shift in the Bermuda High west edge increases ozone over the entire eastern United States by 1–2 ppbv deg−1 in latitude. None of the synoptic patterns identified in this study show a significant trend from 1980 to 2012, confirming that the observed ozone decrease over the eastern United States during this time period is mainly caused by emission controls. Our work underscores the impact of synoptic patterns on ozone variability and suggests that a combination of changing local and synoptic meteorology together with trends in background ozone will determine the influence of climate change on US ozone air quality in future decades. The observed relationships of US surface ozone and synoptic circulations in this study can also be used to validate models of atmospheric chemistry.

scholarly journals The response of surface ozone to climate change over the Eastern United States

2008 ◽  
Vol 8 (4) ◽  
pp. 871-885 ◽  
Author(s):  
P. N. Racherla ◽  
P. J. Adams
Keyword(s):  
Climate Change ◽  
United States ◽  
Interannual Variability ◽  
Surface Ozone ◽  
Primary Standard ◽  
Future Climate ◽  
Future Climate Change ◽  
Eastern United States ◽  
Chemical Production ◽  
Ipcc Sres

Abstract. We investigate the response of surface ozone (O3) to future climate change in the eastern United States by performing simulations corresponding to present (1990s) and future (2050s) climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050s decade. Present-day anthropogenic emissions and CO2/CH4 mixing ratios have been used in both simulations while climate-sensitive emissions were allowed to vary with the simulated climate. The severity and frequency of O3 episodes in the eastern U.S. increased due to future climate change, primarily as a result of increased O3 chemical production. The 95th percentile O3 mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range; the US EPA's current 8-h ozone primary standard is 80 ppbv. The increased O3 chemical production is due to increases in: 1) natural isoprene emissions; 2) hydroperoxy radical concentrations resulting from increased water vapor concentrations; and, 3) NOx concentrations resulting from reduced PAN. The most substantial and statistically significant (p<0.05) increases in episode frequency occurred over the southeast and midatlantic U.S., largely as a result of 20% higher annual-average natural isoprene emissions. These results suggest a lengthening of the O3 season over the eastern U.S. in a future climate to include late spring and early fall months. Increased chemical production and shorter average lifetime are two consistent features of the seasonal response of surface O3, with increased dry deposition loss rates contributing most to the reduced lifetime in all seasons except summer. Significant interannual variability is observed in the frequency of O3 episodes and we find that it is necessary to utilize 5 years or more of simulation data in order to separate the effects of interannual variability and climate change on O3 episodes in the eastern United States.

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