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Sample records for affect tropospheric ozone

  1. Processes Affecting Tropospheric Ozone over Africa

    NASA Technical Reports Server (NTRS)

    Diab, Roseanne D.; Thompson, Anne M.

    2004-01-01

    This is a Workshop Report prepared for Eos, the weekly AGU magazine, The workshop took place between 26-28 January 2004 at the University of KwaZulu-Natal in Durban, South Africa and was attended by 26 participants (http//www.geography.und.ac.za). Considerable progress has been made in ozone observations except for northern Africa (large data gaps) and west Africa (to be covered by the French-sponsored AMMA program). The present-day ozone findings were evaluated and reviewed by speakers using Aircraft data (MOZAIC program), NASA satellites (MOPITT, TRMM, TOMS) and ozone soundings (SHADOZ). Besides some ozone gaps, there are challenges posed by the need to assess the relative strengths of photochemical and dynamic influences on the tropospheric ozone budget. Biogenic, biofuels, biomass burning sources of ozone precursors remain highly uncertain. Recent findings (by NASA's Chatfield and Thompson, using satellite and sounding data) show significant impact of Indian Ocean pollution on African ozone. European research on pollutants over the Mediterranean and the middle east, that suggests that ozone may be exported to Africa from these areas, also needs to be considered.

  2. Ozone, Tropospheric

    NASA Technical Reports Server (NTRS)

    Fishman, Jack

    1995-01-01

    In the early part of the 20th century, ground-based and balloon-borne measurements discovered that most of atmosphere's ozone is located in the stratosphere with highest concentrations located between 15 and 30 km (9,3 and 18.6 miles). For a long time, it was believed that tropospheric ozone originated from the stratosphere and that most of it was destroyed by contact with the earth's surface. Ozone, O3, was known to be produced by the photo-dissociation of molecular oxygen, O2, a process that can only occur at wavelengths shorter than 242 nm. Because such short-wave-length radiation is present only in the stratosphere, no tropospheric ozone production is possible by this mechanism. In the 1940s, however, it became obvious that production of ozone was also taking place in the troposphere. The overall reaction mechanism was eventually identified by Arie Haagen-Smit of the California Institute of Technology, in highly polluted southern California. The copious emissions from the numerous cars driven there as a result of the mass migration to Los Angeles after World War 2 created the new unpleasant phenomenon of photochemical smog, the primary component of which is ozone. These high levels of ozone were injuring vegetable crops, causing women's nylons to run, and generating increasing respiratory and eye-irritation problems for the populace. Our knowledge of tropospheric ozone increased dramatically in the early 1950s as monitoring stations and search centers were established throughout southern California to see what could be done to combat this threat to human health and the environment.

  3. Global tropospheric ozone investigations

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.

    1998-01-01

    Ozone (O3) is one of the most important trace gases in the troposphere, and it is responsible for influencing many critical chemical and radiative processes. Ozone contributes to the formation of the hydroxyl radical (OH), which is central to most chemical reactions in the lower atmosphere, and it absorbs UV, visible, and infrared radiation which affects the energy budget and atmospheric temperatures. In addition, O3 can be used as a tracer of atmospheric pollution and stratosphere troposphere exchange. At elevated concentrations, O3 can also produce detrimental biological and human health effects. The US National Research Council (NRC) Board on Sustainable Development reviewed the US Global Change Research Program (USGCRP) [NRC, 1995], and it identified tropospheric chemistry as one of the high priority areas for the USGCRP in the next decade. The NRC identified the following specific challenges in tropospheric chemistry. Although we understand the reason for the high levels of 03 over several regions of the world, we need to better establish the distribution of O3 in the troposphere in order to document and understand the changes in the abundance of global tropospheric O3. This information is needed to quantify the contribution of O3 to the Earth' s radiative balance and to understand potential impacts on the health of the biosphere. Having recognized the importance of particles in the chemistry of the stratosphere, we must determine how aerosols and clouds affect the chemical processes in the troposphere. This understanding is essential to predict the chemical composition of the atmosphere and to assess the resulting forcing effects in the climate system. We must determine if the self-cleansing chemistry of the atmosphere is changing as a result of human activities. This information is required to predict the rate at which pollutants are removed from the atmosphere. Over nearly two decades, airborne Differential Absorption Lidar (DIAL) systems have been used in

  4. Tropospheric Ozone and Photochemical Smog

    NASA Astrophysics Data System (ADS)

    Sillman, S.

    2003-12-01

    emitted species, in a process that is driven by sunlight and is accelerated by warm temperatures. This smog is largely the product of gasoline-powered engines (especially automobiles), although coal-fired industry can also generate photochemical smog. The process of photochemical smog formation was first identified by Haagen-Smit and Fox (1954) in association with Los Angeles, a city whose geography makes it particularly susceptible to this type of smog formation. Sulfate aerosols and organic particulates are often produced concurrently with ozone, giving rise to a characteristic milky-white haze associated with this type of air pollution.Today ozone and particulates are recognized as the air pollutants that are most likely to affect human health adversely. In the United States, most major metropolitan areas have periodic air pollution events with ozone in excess of government health standards. Violations of local health standards also occur in major cities in Canada and in much of Europe. Other cities around the world (especially Mexico City) also experience very high ozone levels. In addition to urban-scale events, elevated ozone occurs in region-wide events in the eastern USA and in Western Europe, with excess ozone extending over areas of 1,000 km2 or more. Ozone plumes of similar extent are found in the tropics (especially in Central Africa) at times of high biomass burning (e.g., Jenkins et al., 1997; Chatfield et al., 1998). In some cases ozone associated with biomass burning has been identified at distances up to 104 km from its sources (Schultz et al., 1999).Ozone also has a significant impact on the global troposphere, and ozone chemistry is a major component of global tropospheric chemistry. Global background ozone concentrations are much lower than urban or regional concentrations during pollution events, but there is evidence that the global background has increased as a result of human activities (e.g., Wang and Jacob, 1998; Volz and Kley, 1988). A rise in

  5. Source attribution of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  6. Tropospheric ozone variability over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pavan S.; Bortoli, D.; Salgado, R.; Antón, M.; Costa, M. J.; Silva, A. M.

    2011-01-01

    To study tropospheric ozone variability over the Iberian Peninsula (IP), NASA Langley TOR data have been analyzed for the 1979-2005 period. The maximum tropospheric ozone concentration over the entire IP was found in June (˜41 DU) and a minimum in December (˜29 DU). However the maximum tropospheric ozone concentration was found over West Atlantic Coast (WAC) (˜44 DU), followed by Mediterranean Coast (MC) (˜42 DU), North Atlantic Coast (NAC) (˜41 DU), Central Iberian Peninsula (CIP) (˜40 DU) and Pyrenees Mountain Range (PMR) (˜39 DU) during June-July. The high concentration of tropospheric ozone in July over the Atlantic Ocean near IP is due to the presence of Azores anticyclone and related photochemistry and dynamics, and affects the observed higher tropospheric ozone concentration over WAC zone. Strong seasonal cycle in tropospheric ozone concentration has been observed with large variation over NAC (˜49%), followed by WAC (˜48%) and MC (˜41%) compared to CIP and PMR (˜38%) zones. When the data are compared over the IP for the two periods (1979-1993 and 1997-2005), a systematic increase in the number of months with higher tropospheric ozone concentration has been observed during the second period with respect to the first. These increases are almost 8% to 24% over NAC, 6% to 17% over WAC, 5% to 24% over CIP, 6% to 23% over MC and 13% to 18% over PMR, zones. It has been observed that topography, climatology and population density distribution plays a crucial role in the variability of tropospheric ozone concentration over the IP.

  7. Tropospheric Ozone Over North America

    NASA Astrophysics Data System (ADS)

    Oltmans, S. J.; Thompson, A. M.; Cooper, O. R.; Merrill, J. T.; Tarasick, D. W.; Newchurch, M. J.

    2007-05-01

    Ozone in the troposphere plays a significant role as an absorber of infrared radiation (greenhouse gas), in the cleansing capacity of the atmosphere as a precursor of hydroxol radical formation, and a regulated air pollutant capable of deleterious health and ecosystem effects. Knowledge of the ozone budget in the troposphere over North America (NA) is required to properly understand the various mechanisms that contribute to the measured distribution and to develop and test models capable of simulating and predicting this key player in atmospheric chemical and physical processes. Recent field campaigns including the 2004 and 2006 INTEX Ozone Network Studies (IONS) http:croc.gsfc.nasa.gov/intexb/ions06.html that have included intensive ozone profile measurements from ozonesondes provide a unique data set for describing tropospheric ozone over a significant portion of the North American continent. These campaigns have focused on the spring and summer seasons when tropospheric ozone over NA is particularly influenced by long-range transport processes, significant photochemical ozone production resulting from both anthropogenic and natural (lightning) precursor emissions, and exchange with the stratosphere. This study uses ozone profiles measured over NA in the latitude band from approximately 12-60N, extending from the tropics to the high mid latitudes, to describe the seasonal behavior of tropospheric ozone over NA with an emphasis on the spring and summer. This includes the variability within seasons at a particular site as well as the contrasts between the seasons. Emphasis is placed on the variations among the sites including latitudinal and longitudinal gradients and how these differ through the seasons and with altitude in the troposphere. Regional differences are most pronounced during the summer season likely reflecting the influence of a wider variation in processes influencing the tropospheric ozone distribution including lightning NOX production in the upper

  8. Observing Tropospheric Ozone From Space

    NASA Technical Reports Server (NTRS)

    Fishman, Jack

    2000-01-01

    The importance of tropospheric ozone embraces a spectrum of relevant scientific issues ranging from local environmental concerns, such as damage to the biosphere and human health, to those that impact global change questions, Such is climate warming. From an observational perspective, the challenge is to determine the tropospheric ozone global distribution. Because its lifetime is short compared with other important greenhouse gases that have been monitored over the past several decades, the distribution of tropospheric ozone cannot be inferred from a relatively small set of monitoring stations. Therefore, the best way to obtain a true global picture is from the use of space-based instrumentation where important spatial gradients over vast ocean expanses and other uninhabited areas can be properly characterized. In this paper, the development of the capability to measure tropospheric ozone from space over the past 15 years is summarized. Research in the late 1980s successfully led to the determination of the climatology of tropospheric ozone as a function of season; more recently, the methodology has improved to the extent where regional air pollution episodes can be characterized. The most recent modifications now provide quasi-global (50 N) to 50 S) maps on a daily basis. Such a data set would allow for the study of long-range (intercontinental) transport of air pollution and the quantification of how regional emissions feed into the global tropospheric ozone budget. Future measurement capabilities within this decade promise to offer the ability to provide Concurrent maps of the precursors to the in situ formation of tropospheric ozone from which the scientific community will gain unprecedented insight into the processes that control global tropospheric chemistry

  9. Plant responses to tropospheric ozone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone is the second most abundant air pollutant and an important component of the global climate change. Over five decades of research on the phytotoxicity of ozone in model plants systems, crop plants and forest trees have provided some insight into the physiological, biochemical and m...

  10. Effects of stratospheric ozone recovery on photochemistry and ozone air quality in the troposphere

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wu, S.; Huang, Y.; Wang, Y.

    2014-04-01

    There has been significant stratospheric ozone depletion since the late 1970s due to ozone-depleting substances (ODSs). With the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. In this study, we examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). With a full recovery of the stratospheric ozone, the projected increases in ozone column range from 1% over the low latitudes to more than 10% over the polar regions. The sensitivity factor of troposphere ozone photolysis rate, defined as the percentage changes in surface ozone photolysis rate for 1% increase in stratospheric ozone column, shows significant seasonal variation but is always negative with absolute value larger than one. The expected stratospheric ozone recovery is found to affect the tropospheric ozone destruction rates much more than the ozone production rates. Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. The global average tropospheric OH decreases by 1.7%, and the global average lifetime of tropospheric ozone increases by 1.5%. The perturbations to tropospheric ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 0.8 ppbv in the remote areas. Increases in ozone lifetime by up to 13% are found in the troposphere. The increased lifetimes of tropospheric ozone in response to stratospheric ozone recovery enhance the intercontinental transport of ozone and global pollution, in particular for the summertime. The global background ozone attributable to Asian emissions is calculated to increase by up to 15% or 0.3 ppbv in the Northern Hemisphere in response to the projected stratospheric ozone recovery.

  11. Climate Impacts on Tropospheric Ozone and Hydroxyl

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.; Bell, N.; Faluvegi, G.

    2003-01-01

    Climate change may influence tropospheric ozone and OH via several main pathways: (1) altering chemistry via temperature and humidity changes, (2) changing ozone and precursor sources via surface emissions, stratosphere-troposphere exchange, and light- ning, and (3) affecting trace gas sinks via the hydrological cycle and dry deposition. We report results from a set of coupled chemistry-climate model simulations designed to systematically study these effects. We compare the various effects with one another and with past and projected future changes in anthropogenic and natural emissions of ozone precursors. We find that white the overall impact of climate on ozone is probably small compared to emission changes, some significant seasonal and regional effects are apparent. The global effect on hydroxyl is quite large, however, similar in size to the effect of emission changes. Additionally, we show that many of the chemistry-climate links that are not yet adequately modeled are potentially important.

  12. How do increasing background concentrations of tropospheric ozone affect peatland plant growth and carbon gas exchange?

    NASA Astrophysics Data System (ADS)

    Williamson, Jennifer L.; Mills, Gina; Hayes, Felicity; Jones, Timothy; Freeman, Chris

    2016-02-01

    In this study we have demonstrated that plants originating from upland peat bogs are sensitive to increasing background concentrations of ozone. Peatland mesocosms from an upland peat bog in North Wales, UK were exposed to eight levels of elevated background ozone in solardomes for 4 months from May to August, with 24 h mean ozone concentrations ranging from 16 to 94 ppb and cumulative AOT024hr ranging from 45.98 ppm h to 259.63 ppm h. Our results show that plant senescence increased with increasing exposure to ozone, although there was no significant effect of increasing ozone on plant biomass. Assessments of carbon dioxide and methane fluxes from the mesocosms suggests that there was no change in carbon dioxide fluxes over the 4 month exposure period but that methane fluxes increased as cumulative ozone exposure increased to a maximum AOT 024hr of approximately 120 ppm h and then decreased as cumulative ozone exposure increased further.

  13. Meteorological factors affecting lower tropospheric ozone mixing ratios in Bangkok, Thailand

    NASA Astrophysics Data System (ADS)

    Janjai, S.; Buntoung, S.; Nunez, M.; Chiwpreecha, K.; Pattarapanitchai, S.

    2016-09-01

    This paper examines the influence of meteorological conditions in ozone mixing ratio measured at the Thai Meteorological Department (TMD) in Bangkok, Thailand. In addition to surface wind speed and direction, surface ozone concentrations, ozonesondes and CALIPSO Lidar images were collected during the study period extending from 01/01/2014 to 30/04/2015. Surface ozone concentrations show a strong seasonality, with maximum in the dry months of December to April and minimum during the wet southwest (SW) monsoon period extending from May to October. High ozone concentrations are related to biomass burning in the northeast highland regions of the country and neighboring Myanmar and southern China. These precursors travel in a southerly direction towards Bangkok in a well-defined aerosol layer which may be at ground level or at elevated heights. The growth of the daytime mixed layer scavenges some of the upper level aerosols, although local maxima in ozone concentrations at 1-2 km are a frequent feature at Bangkok. There is an evidence of fumigation in the Gulf of Thailand and a return flow via the southerly sea breezes.

  14. Discoveries about Tropospheric Ozone Pollution from Satellite and Sounding

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.

    2004-01-01

    We have been producing near-real time tropospheric ozone satellite maps from the TOMS (Total Ozone Mapping Spectrometer) sensor since 1997. This is most readily done for the tropics, where the stratospheric and tropospheric ozone column amounts can be discriminated readily. Maps for 1996-2000 for the operational Earth-Probe instrument reside at: chttp://www.atmos.umd.edu/-trope>. Pollution in the tropics is influenced by biomass burning and by transport patterns that favor recirculation and in other cases reflect climate variability like the El-Nino-Southern Oscillation [Thompson et al., 2001]. Time permitting, examples of mid-latitude, intercontinental transport of ozone pollution sensed by TOMS will be shown. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical variability. Thus, in 1998, NASA's Goddard Space Flight Center and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches and provides a public archive of ozonesonde data from twelve tropical stations at http://croc.gsfc.nasa.gov/shadoz. Further insights into the role of chemical and dynamical influences have emerged from the first 4-5 years of SHADOZ data (less than 2000 ozone profiles): (a) highly variable tropospheric ozone; (b) a zonal wave-one pattern in tropospheric column ozone; (c) convective variability affects tropospheric ozone over the Indian and Pacific Ocean; (d) a "tropical Atlantic Paradox" appears in December-January-February.

  15. Tropospheric Ozone and Biomass Burning

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Ziemke, J. R.; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    This paper studies the significance of pyrogenic (e.g., biomass burning) emissions in the production of tropospheric ozone in the tropics associated with the forest and savanna fires in the African, South American, and Indonesian regions. Using aerosol index (Al) and tropospheric column ozone (TCO) time series from 1979 to 2000 derived from the Nimbus-7 and Earth Probe TOMS measurements, our study shows significant differences in the seasonal and spatial characteristics of pyrogenic emissions north and south of the equator in the African region and Brazil in South America. In general, they are not related to the seasonal and spatial characteristics of tropospheric ozone in these regions. In the Indonesian region, the most significant increase in TCO occurred during September and October 1997, following large-scale forest and savanna fires associated with the El Nino-induced dry season. However, the increase in TCO extended over most of the western Pacific well outside the burning region and was accompanied by a decrease in the eastern Pacific resembling a west-to-east dipole about the date-line. The net increase in TCO integrated over the tropical region between 15 deg N and 15 deg S was about 6-8 Tg (1 Tg = 10(exp 12) gm) over the mean climatological value of about 72 Tg. This increase is well within the range of interannual variability of TCO in the tropical region and does not necessarily suggest a photochemical source related to biomass burning. The interannual variability in TCO appears to be out of phase with the interannual variability of stratospheric column ozone (SCO). These variabilities seem to be manifestations of solar cycle and quasibiennial oscillations.

  16. Tropospheric Ozone from the TOMS TDOT (TOMS-Direct-Ozone-in-Troposphere) Technique During SAFARI-2000

    NASA Technical Reports Server (NTRS)

    Stone, J. B.; Thompson, A. M.; Frolov, A. D.; Hudson, R. D.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    There are a number of published residual-type methods for deriving tropospheric ozone from TOMS (Total Ozone Mapping Spectrometer). The basic concept of these methods is that within a zone of constant stratospheric ozone, the tropospheric ozone column can be computed by subtracting stratospheric ozone from the TOMS Level 2 total ozone column, We used the modified-residual method for retrieving tropospheric ozone during SAFARI-2000 and found disagreements with in-situ ozone data over Africa in September 2000. Using the newly developed TDOT (TOMS-Direct-Ozone-in-Troposphere) method that uses TOMS radiances and a modified lookup table based on actual profiles during high ozone pollution periods, new maps were prepared and found to compare better to soundings over Lusaka, Zambia (15.5 S, 28 E), Nairobi and several African cities where MOZAIC aircraft operated in September 2000. The TDOT technique and comparisons are described in detail.

  17. Tropospheric Enhancement of Ozone over the UAE

    NASA Astrophysics Data System (ADS)

    Abbasi, Naveed Ali; Majeed, Tariq; Iqbal, Mazhar; Kaminski, Jacek; Struzewska, Joanna; Durka, Pawel; Tarasick, David; Davies, Jonathan

    2015-04-01

    We use the Global Environmental Multiscale - Air Quality (GEM-AQ) model to interpret the vertical profiles of ozone acquired with ozone sounding experiments at the meteorological site located at the Abu Dhabi airport. The purpose of this study is to gain insight into the chemical and dynamical structures in the atmosphere of this unique subtropical location (latitude 24.45N; longitude 54.22E). Ozone observations for years 2012 - 2013 reveal elevated ozone abundances in the range from 70 ppbv to 120 ppbv near 500-400 hPa during summer. The ozone abundances in other seasons are much lower than these values. The preliminary results indicate that summertime enhancement in ozone is associated with the Arabian anticyclones centered over the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water. The model also shows considerable seasonal variation in the tropospheric ozone which is transported from the stratosphere by dynamical processes. The domestic production of ozone in the middle troposphere is estimated and compared GEM-AQ model. It is estimated that about 40-50% of ozone in the UAE is transported from the neighbouring petrochemical industries in the Gulf region. We will present ozone sounding data and GEM-AQ results including a discussion on the high levels of the tropospheric ozone responsible for contaminating the air quality in the UAE. This work is supported by National Research Foundation, UAE.

  18. Impact of climate variability on tropospheric ozone.

    PubMed

    Grewe, Volker

    2007-03-01

    A simulation with the climate-chemistry model (CCM) E39/C is presented, which covers both the troposphere and stratosphere dynamics and chemistry during the period 1960 to 1999. Although the CCM, by its nature, is not exactly representing observed day-by-day meteorology, there is an overall model's tendency to correctly reproduce the variability pattern due to an inclusion of realistic external forcings, like observed sea surface temperatures (e.g. El Niño), major volcanic eruption, solar cycle, concentrations of greenhouse gases, and Quasi-Biennial Oscillation. Additionally, climate-chemistry interactions are included, like the impact of ozone, methane, and other species on radiation and dynamics, and the impact of dynamics on emissions (lightning). However, a number of important feedbacks are not yet included (e.g. feedbacks related to biogenic emissions and emissions due to biomass burning). The results show a good representation of the evolution of the stratospheric ozone layer, including the ozone hole, which plays an important role for the simulation of natural variability of tropospheric ozone. Anthropogenic NO(x) emissions are included with a step-wise linear trend for each sector, but no interannual variability is included. The application of a number of diagnostics (e.g. marked ozone tracers) allows the separation of the impact of various processes/emissions on tropospheric ozone and shows that the simulated Northern Hemisphere tropospheric ozone budget is not only dominated by nitrogen oxide emissions and other ozone pre-cursors, but also by changes of the stratospheric ozone budget and its flux into the troposphere, which tends to reduce the simulated positive trend in tropospheric ozone due to emissions from industry and traffic during the late 80s and early 90s. For tropical regions the variability in ozone is dominated by variability in lightning (related to ENSO) and stratosphere-troposphere exchange (related to Northern Hemisphere Stratospheric

  19. Influence of Mountains on Arctic Tropospheric Ozone

    NASA Astrophysics Data System (ADS)

    Whiteway, J. A.; Seabrook, J.

    2015-12-01

    Tropospheric ozone was measured above Ellesmere Island in the Canadian Arctic during spring using a differential absorption lidar (DIAL). Analysis of the observations revealed that mountains had a significant effect on the vertical distribution of ozone. Ozone depletion events were observed when air that had spent significant time near to the frozen surface of the Arctic Ocean reached Eureka. This air arrived at Eureka by flowing over the surrounding mountains. Surface level ozone depletion events were not observed during periods when mountains blocked the flow of air from over the sea ice. In the case of blocking there was an enhancement in the amount of ozone near the surface as air from the mid troposphere descended in the lee of the mountains. Three case studies will be presented.

  20. Tracking the sources of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Butler, T. M.; Churkina, G.; Coates, J.; Grote, R.; Mar, K.; von Schneidemesser, E.; Zhu, S.

    2013-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this set of studies we examine the attribution of tropospheric ozone to emissions of VOC using a tagging approach, whereby each VOC oxidation intermediate in model chemical mechanisms is tagged with the identity of its primary emitted compound, allowing modelled ozone production to be directly attributed to all emitted VOCs in the model. Using a global model we

  1. The High Resolution Tropospheric Ozone Residual

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.

    2006-01-01

    The co-flight of the MLS stratospheric limb sounder and the Ozone Monitoring Instrument (OMI) provides the capability of computing the Tropospheric Ozone Residual (TOR) in much greater detail [Ziemke et al., 2006]. Using forward trajectory calculations of MLS ozone measurements combined with OMI column ozone we have developed a high horizontal resolution tropospheric ozone residual (HTOR) which can provide even more detail than the standard TOR product. HTOR is especially useful for extra-tropical studies of tropospheric ozone transport. We find that both the Pacific pollution corridor (East Asia to Alaska) and the Atlantic pollution corridor (North America east coast to Europe) are also preferred locations for strat-trop folds leading to systematic overestimates of pollution amounts. In fact, fold events appear to dominate extra-tropical Northern Hemisphere day-to-day maps of HTOR. Model estimates of the tropospheric column are in reasonable agreement with the HTOR amounts when offsets due to different tropopause height calculations are taken into consideration.

  2. Ozone density measurements in the troposphere and stratosphere of Natal

    NASA Technical Reports Server (NTRS)

    Kirchhoff, V. W. J. H.; Motta, A. G.

    1983-01-01

    Ozone densitities were measured in the troposphere and stratosphere of Natal using ECC sondes launches on balloons. The data analyzed so far show tropospheric densities and total ozone contents larger than expected.

  3. Influence of mountains on Arctic tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Seabrook, Jeffrey; Whiteway, James

    2016-02-01

    Tropospheric ozone was measured above Ellesmere Island in the Canadian Arctic during spring of 2008 using a differential absorption lidar. The observations were carried out at Eureka Weather Station, which is located between various mountain ranges. Analysis of the observations revealed that mountains had a significant effect on the vertical distribution of ozone. Ozone depletion events were observed when air that had spent significant time near to the frozen surface of the Arctic Ocean reached Eureka. This air arrived at Eureka by flowing over the surrounding mountains. Surface level ozone depletions were not observed during periods when mountains blocked the flow of air from over the sea ice. In the case of blocking there was an enhancement in the amount of ozone near the surface as air from the midtroposphere descended in the lee of the mountains. Three case studies from spring of 2008 are described.

  4. Tropospheric Ozone Lidar Network (TOLNet) - Long-term Tropospheric Ozone and Aerosol Profiling for Satellite Continuity and Process Studies

    NASA Astrophysics Data System (ADS)

    Newchurch, M.; Al-Saadi, J. A.; Alvarez, R. J.; Burris, J.; Cantrell, W.; Chen, G.; De Young, R.; Hardesty, R.; Hoff, R. M.; Kaye, J. A.; kuang, S.; Langford, A. O.; LeBlanc, T.; McDermid, I. S.; McGee, T. J.; Pierce, R.; Senff, C. J.; Sullivan, J. T.; Szykman, J.; Tonnesen, G.; Wang, L.

    2012-12-01

    An interagency research initiative for ground-based ozone and aerosol lidar profiling recently funded by NASA has important applications to air-quality studies in addition to the goal of serving the GEO-CAPE and other air-quality missions. Ozone is a key trace-gas species, a greenhouse gas, and an important pollutant in the troposphere. High spatial and temporal variability of ozone affected by various physical and photochemical processes motivates the high spatio-temporal lidar profiling of tropospheric ozone for improving the simulation and forecasting capability of the photochemical/air-quality models, especially in the boundary layer where the resolution and precision of satellite retrievals are fundamentally limited. It is well known that there are large discrepancies between the surface and upper-air ozone due to titration, surface deposition, diurnal processes, free-tropospheric transport, and other processes. Near-ground ozone profiling has been technically challenging for lidars due to some engineering difficulties, such as near-range saturation, field-of-view overlap, and signal processing issues. This initiative provides an opportunity for us to solve those engineering issues and redesign the lidars aimed at long-term, routine ozone/aerosol observations from the near surface to the top of the troposphere at multiple stations (i.e., NASA/GSFC, NASA/LaRC, NASA/JPL, NOAA/ESRL, UAHuntsville) for addressing the needs of NASA, NOAA, EPA and State/local AQ agencies. We will present the details of the science investigations, current status of the instrumentation development, data access/protocol, and the future goals of this lidar network. Ozone lidar/RAQMS comparison of laminar structures.

  5. Elevated Tropospheric Ozone over the Atlantic

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Tie, X.

    2003-01-01

    Tropospheric column ozone (TCO) is derived from differential measurements of TOMS total column ozone and Microwave Limb Sounder stratospheric column ozone. It is shown that TCO during summer months over the Atlantic and Pacific Oceans in northern midlatitudes is about the same (50 to 60 Dobson Units) as over the continents of North America, Europe, and Asia, where surface emissions of nitrogen oxides from industrial sources, biomass and biofuel burning and biogenic emissions are significantly larger. This nearly uniform zonal variation in TCO is modulated by surface topography of the Rocky and Himalayan mountains, and Tibetan plateau where TCO is reduced by 20 to 30 Dobson Units. The zonal variation in TCO is well simulated by a global chemical transport model called MOZART-2 (Model of Ozone and Related Chemical Tracers, version 2). The model results are analyzed to delineate the relative importance of various processes contributing to observed zonal characteristics of TCO.

  6. Science Accomplishments from a Decade of Aura OMI/MLS Tropospheric Ozone Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerald R.; Douglass, Anne R.; Joiner, Joanna; Duncan, Bryan N.; Olsen, Mark A.; Oman, Luke D.; Witte, Jacquelyn C.; Liu, X.; Wargan, K.; Schoeberl, Mark R.; Strahan, Susan E.; Pawson, Steven; Bhartia, Pawan K.; Newman, Paul A.; Froidevaux, Lucien; Cooper, Owen R.; Haffner, David P.

    2014-01-01

    Measurements of tropospheric ozone from combined Aura OMI and MLS instruments have yielded a large number of new and important science discoveries over the last decade. These discoveries have generated a much greater understanding of biomass burning, lightning NO, and stratosphere-troposphere exchange sources of tropospheric ozone, ENSO dynamics and photochemistry, intra-seasonal variability-Madden-Julian Oscillation including convective transport, radiative forcing, measuring ozone pollution from space, improvements to ozone retrieval algorithms, and evaluation of chemical-transport and chemistry-climate models. The OMI-MLS measurements have been instrumental in giving us better understanding of the dynamics and chemistry involving tropospheric ozone and the many drivers affecting the troposphere in general. This discussion will provide an overview focusing on our main science results.

  7. Enhancement of free tropospheric ozone production by deep convection

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.; Thompson, Anne M.; Scala, John R.; Tao, Wei-Kuo; Simpson, Joanne

    1994-01-01

    It is found from model simulations of trace gas and meteorological data from aircraft campaigns that deep convection may enhance the potential for photochemical ozone production in the middle and upper troposphere by up to a factor of 60. Examination of half a dozen individual convective episodes show that the degree of enhancement is highly variable. Factors affecting enhancement include boundary layer NO(x) mixing ratios, differences in the strength and structure of convective cells, as well as variation in the amount of background pollution already in the free troposphere.

  8. Tropospheric ozone in the vicinity of the ozone hole - 1987 Airborne Antarctic Ozone Experiment

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Warren, Linda S.; Hypes, Warren D.; Tuck, Adrian F.; Kelly, Kenneth K.; Krueger, Arlin J.

    1989-01-01

    Results are presented on ozone measurements in the upper troposphere/lower stratosphere over Antarctica, obtained by NASA DC-8 aircraft during the August/September 1987 Airborne Antarctic Ozone Experiment. The ozone mixing ratios as high as several hundred ppbv were measured, but in all cases these ratios were observed in pockets of upper atmospheric air, both in the vicinity of and away from the location of the ozone hole. The background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed in the course of the experiment. During the August 28 - September 2 flights, encounters with ozone-rich air were limited, and the background tropospheric ozone appeared to decrease beneath the hole. For the later flights, and as the ozone hole deepened, the ozone-rich air was frequently observed in the vicinity of the hole, and the average ozone values at the flight altitude were frequently higher than the background values.

  9. Derivation of Tropospheric Ozone Climatology and Trends from TOMS Data

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; McPeters, Rich; Logan, Jennifer; Kim, Jae-Hwan

    2002-01-01

    This research addresses the following three objectives: (1) Derive tropospheric ozone columns from the TOMS instruments by computing the difference between total-ozone columns over cloudy areas and over clear areas in the tropics; (2) Compute secular trends in Nimbus-7 derived tropospheric Ozone column amounts and associated potential trends in the decadal-scale tropical cloud climatology; (3) Explain the occurrence of anomalously high ozone retrievals over high ice clouds.

  10. Ozone Modes and Differences in the Variability of Measured and Simulated Tropospheric Ozone Mixing Ratios

    NASA Astrophysics Data System (ADS)

    Stockwell, W. R.; Fitzgerald, R. M.; Lu, D.

    2013-12-01

    Modes are found in measured and modeled aerosol distributions and they illuminate processes affecting aerosol properties but there has been much less examination of modes in tropospheric ozone distributions. The Paso del Norte region was used as a test-bed because of the availability of ozone measurements and because of its relative isolation. The Comprehensive Air Quality Model with Extensions (CAM-X) was used to perform wintertime ozone simulations with two versions of the Carbon Bond mechanism. The objective of this study is to examine differences by modes in the measured and simulated ozone distributions. Although there are differences in the error and bias of the simulated ozone mixing ratios due to the choice of mechanism, the boundary conditions, emissions and other factors should have had a much lower affect on the simulated ozone variability, distribution and modes. The simulations made with two versions of the Carbon Bond mechanism showed large differences in their calculated ozone distributions. While the measured distribution and the Carbon Bond mechanism, version 4 showed three modes the more recent version 5 was very different with only two modes. Furthermore the distributions show that the probability of low ozone mixing ratios is much greater in the measurements than in the simulated ozone. These differences may show systematic problems in the chemical mechanisms for urban and regional air quality models and it illustrates the potential utility of the examination modes in ozone data for the evaluation of air quality models.

  11. Tropospheric ozone in the vicinity of the ozone hole: 1987 Airborne Antarctic Ozone Experiment

    SciTech Connect

    Gregory, G.L.; Warren, L.S. ); Hypes, W.D. ); Tuck, A.F.; Kelly, K.K. ); Krueger, A.J. )

    1989-11-30

    Tropospheric ozone measurements over Antarctica aboard the NASA DC-8 aircraft are summarized. As part of the August/September 1987 Airborne Antarctic Ozone Experiment, the aircraft flew 13 missions covering a latitude of 53{degree}-90{degree}S, at altitudes to 13 km. Ozone mixing ratios as high as several hundred parts per billion by volume (ppbv) were measured, but in all cases these ratios were observed in pockets or patches of upper atmospheric air. These pockets were observed both in the vicinity of and away from the location of the ozone hole. At times, and as a result of these pockets, the ozone levels at the flight altitude of the aircraft, as averaged beneath the boundaries of the stratospheric ozone hole, were 2-3 times higher than background tropospheric values. The data suggest that the ozone-rich air seldom penetrated below about 9-km altitude. Background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed during the experiment. During the early flights (August 28 through September 2), encounters with ozone-rich air were limited and background tropospheric ozone (at the flight altitude) appeared to decrease beneath the hole. For many of the later flights, and as the hole deepened, the reverse was noted, in that ozone-rich air was frequently observed in the vicinity of the hole and, as noted earlier, average ozone at the flight altitude was frequently higher than background values.

  12. Tropospheric and stratospheric ozone from assimilation of Aura data

    NASA Technical Reports Server (NTRS)

    Stajner, I.; Wargan, K.; Chang, L.-P.; Hayashi, H.; Pawwson, S.; Froidevaux, L.; Livesey, N.; Bhartia, P. K.

    2006-01-01

    Ozone is an atmospheric trace gas with multiple impacts on the environment. Global ozone fields are needed for air quality predictions, estimation of the ultraviolet radiation reaching the surface, climate-radiation studies, and may also have an impact on longer-term weather predictions. We estimate global ozone fields in the stratosphere and troposphere by combining the data from EOS Aura satellite with an ozone model using data assimilation. Ozone exhibits a large temporal variability in the lower stratosphere. Our previous work showed that assimilation of satellite data from limb-sounding geometry helps constrain ozone profiles in that region. We assimilated ozone data from the Aura Microwave Limb Sounder (MLS) and the Ozone Monitoring Instrument (OMI) into the ozone system at NASA's Global Modeling and Assimilation Office (GMAO). Ozone is transported within a general circulation model (GCM) which includes parameterizations for stratospheric photochemistry, tropospheric chemistry, and a simple scheme for heterogeneous ozone loss. The focus of this study is on the representation of ozone in the lower stratosphere and tropospheric ozone columns. We plan to extend studies of tropospheric ozone distribution through assimilation of ozone data from the Tropospheric Emission Spectrometer (TES). Comparisons with ozone sondes and occultation data show that assimilation of Aura data reproduces ozone gradients and variability in the lower stratosphere well. We proceed by separating the contributions to temporal changes in the ozone field into those that are due to the model and those that are due to the assimilation of Aura data. The impacts of Aura data are illustrated and their role in the representation of ozone variability in the lower stratosphere and troposphere is shown.

  13. Quantifying isentropic stratosphere-troposphere exchange of ozone

    NASA Astrophysics Data System (ADS)

    Yang, Huang; Chen, Gang; Tang, Qi; Hess, Peter

    2016-04-01

    There is increased evidence that stratosphere-troposphere exchange (STE) of ozone has a significant impact on tropospheric chemistry and radiation. Traditional diagnostics of STE consider the ozone budget in the lowermost stratosphere (LMS) as a whole. However, this can only render the hemispherically integrated ozone flux and therefore does not distinguish the exchange of ozone into low latitudes from that into high latitudes. The exchange of ozone at different latitudes may have different tropospheric impacts. This present study extends the traditional approach from the entire LMS to individual isentropic layers in the LMS and therefore gives the meridional distribution of STE by the latitudes where each isentropic surface intersects the tropopause. The specified dynamics version of the Whole Atmosphere Community Climate Model is used to estimate the STE ozone flux on each isentropic surface. It is found that net troposphere-to-stratosphere ozone transport occurs in low latitudes along the 350-380 K isentropic surfaces and that net stratosphere-to-troposphere ozone transport takes place in the extratropics along the 280-350 K isentropes. Particularly, the seasonal cycle of extratropical STE ozone flux in the Northern Hemisphere displays a maximum in late spring and early summer, following the seasonal migration of the upper tropospheric jet and associated isentropic mixing. Furthermore, differential diabatic heating and isentropic mixing tend to induce STE ozone fluxes in opposite directions, but the net effect results in a spatiotemporal pattern similar to the STE ozone flux associated with isentropic mixing.

  14. Ozone in the upper troposphere from Gasp measurements

    NASA Technical Reports Server (NTRS)

    Nastrom, G. D.

    1979-01-01

    Several aspects of tropospheric ozone variations are examined by using ozone measurements made from commercial airliners (Gasp data). Through visual inspection of the autocorrelation function it is shown that the east-west variations of ozone have a predominant wavelength near 2400 km, while temperature and wind have predominant wavelengths near 3300 km. Distance-lagged correlation functions of ozone with temperature and wind show a definite periodicity with wavelengths near 2400 km. Attention is given to the tropical tropospheric ozone values above 100 parts per billion by volume, which appear to be associated with meridional transport from middle latitudes, and in some cases, relatively large tropical ozone values are coincident with clouds.

  15. Impact of Tropospheric Aerosol Absorption on Ozone Retrieval from buv Measurements

    NASA Technical Reports Server (NTRS)

    Torres, O.; Bhartia, P. K.

    1998-01-01

    The impact of tropospheric aerosols on the retrieval of column ozone amounts using spaceborne measurements of backscattered ultraviolet radiation is examined. Using radiative transfer calculations, we show that uv-absorbing desert dust may introduce errors as large as 10% in ozone column amount, depending on the aerosol layer height and optical depth. Smaller errors are produced by carbonaceous aerosols that result from biomass burning. Though the error is produced by complex interactions between ozone absorption (both stratospheric and tropospheric), aerosol scattering, and aerosol absorption, a surprisingly simple correction procedure reduces the error to about 1%, for a variety of aerosols and for a wide range of aerosol loading. Comparison of the corrected TOMS data with operational data indicates that though the zonal mean total ozone derived from TOMS are not significantly affected by these errors, localized affects in the tropics can be large enough to seriously affect the studies of tropospheric ozone that are currently undergoing using the TOMS data.

  16. Linkages Between Ozone-depleting Substances, Tropospheric Oxidation and Aerosols

    NASA Technical Reports Server (NTRS)

    Voulgarakis, A.; Shindell, D. T.; Faluvegi, G.

    2013-01-01

    Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6mW/sq. m for CFCs and -6.7mW/sq. m for N2O) and sulfate aerosols (-3.0mW/sq. m for CFCs and +6.5mW/sq. m for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  17. Linkages between ozone-depleting substances, tropospheric oxidation and aerosols

    NASA Astrophysics Data System (ADS)

    Voulgarakis, A.; Shindell, D. T.; Faluvegi, G.

    2013-05-01

    Coupling between the stratosphere and the troposphere allows changes in stratospheric ozone abundances to affect tropospheric chemistry. Large-scale effects from such changes on chemically produced tropospheric aerosols have not been systematically examined in past studies. We use a composition-climate model to investigate potential past and future impacts of changes in stratospheric ozone depleting substances (ODS) on tropospheric oxidants and sulfate aerosols. In most experiments, we find significant responses in tropospheric photolysis and oxidants, with small but significant effects on methane radiative forcing. The response of sulfate aerosols is sizeable when examining the effect of increasing future nitrous oxide (N2O) emissions. We also find that without the regulation of chlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosols could have increased by 2050 by a comparable amount to the decreases predicted due to relatively stringent sulfur emissions controls. The individual historical radiative forcings of CFCs and N2O through their indirect effects on methane (-22.6 mW m-2 for CFCs and -6.7 mW m-2 for N2O) and sulfate aerosols (-3.0 mW m-2 for CFCs and +6.5 mW m-2 for N2O when considering the direct aerosol effect) discussed here are non-negligible when compared to known historical ODS forcing. Our results stress the importance of accounting for stratosphere-troposphere, gas-aerosol and composition-climate interactions when investigating the effects of changing emissions on atmospheric composition and climate.

  18. Scaling of The Tropospheric Ozone Concentrations and Anthropogenic Effects

    NASA Astrophysics Data System (ADS)

    Audiffren, N.; Duroure, C.

    The statistical characteristics of long time series of ozone mixing ratios in free tro- posphere and in urban environment are compared.We use a five year dataset with 15 minute resolution of ozone concentrations in a free tropospheric condition (Puy de Dôme) and in four different towns in the mesoscale vicinity (Auvergne region), (data from Atmo-Auvergne) The free tropospheric ozone field have the same scaling behaviour (Fourier spectrum, structure functions and intermittency measure) than a passive scalar in a 3D higthly turbulent dynamic field. We don't observe a mesoscale gap and the inertial range is ranging from (at least) one minute to a few days for eule- rian measurements (from hundred meters to hundreds of kilometers for the lagrangian space scale). The probability density functions (PDF) of the ozone mixing ratio incre- ments are higthly non gaussian, with tails decreasing slower than negative exponential, indicating an "intermittent" behaviour. The scale evolution of the intermittency is esti- mated using the normalized fourth moment of the discrete laplacian and is compared with other turbulent geophysical fields (mesoscale cloud coverage, updraft velocity, rainfall serie). On the opposite, for the urban measurements, the modifications of the statistical properties not only affect the mean but also the scaling exponent (Fourier slope closer to -1) and the intermittency structure function. The one day periodic peak is more pronounced than for the free troposphere measurements and appears a (purely anthropogenic) peak of seven days. For large towns ,the PDF of gradient are close to a Levy-stable PDF with a characteristic exponent close to 2 (the Gaussian limit). The anthropogenic effects on ozone concentration make the statistical characteristics closer to those observed for the web flux, the traffic jams, or the properties of speach and music.

  19. Rapid increases in tropospheric ozone production and export from China

    NASA Astrophysics Data System (ADS)

    Verstraeten, Willem W.; Neu, Jessica L.; Williams, Jason E.; Bowman, Kevin W.; Worden, John R.; Boersma, K. Folkert

    2015-09-01

    Rapid population growth and industrialization have driven substantial increases in Asian ozone precursor emissions over the past decade, with highly uncertain impacts on regional and global tropospheric ozone levels. According to ozonesonde measurements, tropospheric ozone concentrations at two Asian sites have increased by 1 to 3% per year since 2000, an increase thought to contribute to positive trends in the ozone levels observed at North America’s West Coast. However, model estimates of the Asian contribution to North American ozone levels are not well-constrained by observations. Here we interpret Aura satellite measurements of tropospheric concentrations of ozone and its precursor NO2, along with its largest natural source, stratospheric ozone, using the TM5 global chemistry-transport model. We show that tropospheric ozone concentrations over China have increased by about 7% between 2005 and 2010 in response to two factors: a rise in Chinese emissions by about 21% and increased downward transport of stratospheric ozone. Furthermore, we find that transport from China of ozone and its precursors has offset about 43% of the 0.42 DU reduction in free-tropospheric ozone over the western United States that was expected between 2005 and 2010 as a result of emissions reductions associated with federal, state and local air quality policies. We conclude that global efforts may be required to address regional air quality and climate change.

  20. Diagnosing changes in European tropospheric ozone: A model study of past and future changes

    NASA Astrophysics Data System (ADS)

    Tummon, Fiona; Revell, Laura; Stenke, Andrea; Staehelin, Johannes; Peter, Thomas

    2016-04-01

    In recent decades, the negative impacts of tropospheric ozone on human and ecosystem health have led to policy changes aimed at reducing emissions of ozone precursor gases such as nitrogen oxides (NOx) and carbon monoxide (CO). Although emissions of these species have significantly decreased in Europe and North America since the early 1990s, observational data indicate that free tropospheric ozone over Europe has not decreased as expected. Uncertainty remains as to how much of a role the transport of stratospheric ozone or tropospheric ozone from remote source regions has played in recent trends, as well as to how this will evolve in a changing climate. The global chemistry-climate model SOCOL (SOlar Chemistry Ozone Links) is used to investigate tropospheric ozone over Europe from 1960 to 2100. To fully disentangle the effects of both long-range transport and input from the stratosphere, simulations are run with ozone tracers from 21 different atmospheric regions. In addition to a standard reference run, several sensitivity simulations are run: one with emissions of NOx and CO held constant at 1960 levels, one with methane (CH4) held at constant 1960 levels (in addition to the NOx and CO), and a third with NOx and CO emissions from Asia fixed at 1960 levels. Results suggest that the largest contributions to European tropospheric ozone originate from the tropical and northern mid-latitude boundary layer and free troposphere. Contributions from these regions increase over the historical period (1960-2010), indicating that changes in source gas emissions have affected ozone concentrations in the European free troposphere most strongly. Contributions from these regions then decrease from 2010-2100, but remain considerably larger than input from the stratosphere, which is relatively small in all simulations throughout the entire simulated period (1960-2100). The stratospheric contribution does, however, increase slightly over the 21st century, in tandem with ozone

  1. A Madden-Julian Oscillation in Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.

    2003-01-01

    This is the first study to indicate a Madden-Julian Oscillation (MJO) in tropospheric ozone. Tropospheric ozone is derived using differential measurements of total column ozone and stratospheric column ozone measured from total ozone mapping spectrometer (TOMS) and microwave limb sounder (MLS) instruments. Two broad regions of significant MJO signal are identified in the tropics, one in the western Pacific and the other in the eastern Pacific. Over both regions, MJO variations in tropospheric ozone represent 5-10 Dobson Unit (DU) peak-to-peak anomalies. These variations are significant compared to mean background amounts of 20 DU or less over most of the tropical Pacific. MJO signals of this magnitude would need to be considered when investigating and interpreting particular pollution events since ozone is a precursor of the hydroxyl (OH) radical, the main oxidizing agent of pollutants in the lower atmosphere.

  2. Compact airborne lidar for tropospheric ozone: description and field measurements.

    PubMed

    Ancellet, G; Ravetta, F O

    1998-08-20

    An airborne lidar has been developed for tropospheric ozone monitoring. The transmitter module is based on a solid-state Nd:YAG laser and stimulated Raman scattering in deuterium to generate three wavelengths (266, 289, and 316 nm) that are used for differential ozone measurements. Both analog and photon-counting detection methods are used to produce a measurement range up to 8 km. The system has been flown on the French Fokker 27 aircraft to perform both lower tropospheric (0.5-4-km) and upper tropospheric (4-12-km) measurements, with a 1-min temporal resolution corresponding to a 5-km spatial resolution. The vertical resolution of the ozone profile can vary from 300 to 1000 m to accommodate either a large-altitude range or optimum ozone accuracy. Comparisons with in situ ozone measurements performed by an aircraft UV photometer or ozone sondes and with ozone vertical profiles obtained by a ground-based lidar are presented. The accuracy of the tropospheric ozone measurements is generally better than 10-15%, except when aerosol interferences cannot be corrected. Examples of ozone profiles for different atmospheric conditions demonstrate the utility of the airborne lidar in the study of dynamic or photochemical mesoscale processes that control tropospheric ozone. PMID:18286036

  3. Tropospheric ozone and aerosol distributions across the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Gregory, G. L.; Harriss, R. C.; Kirchhoff, V. W. J. H.

    1988-01-01

    As a part of the NASA Global Tropospheric Experiment to study the Amazon boundary layer, ozone and aerosol distributions were made measured in July-August 1985 by a NASA Electra aircraft on several long-range flights spanning different areas between Tabatinga and Belem, Brazil. Both positive and negative correlations were found in PBL between aerosol concentrations and O3 mixing ratios. The negative correlations result from the downward transport of relatively clean O3-rich air from the upper troposphere into PBL (which normally has higher aerosol loading and lower O3 concentrations than troposphere); positive correlations are found in biomass-burning plumes, where the aerosols are emitted into the air and O3 is photochemically produced. It was found that, in the dry season, a significant portion of the ozone over the rain forest is a result of biomass burning and that the distribution of photochemically produced O3 is strongly affected by synoptic-scale transport from large fires to the south/southeast.

  4. Retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations

    NASA Astrophysics Data System (ADS)

    Ebojie, F.; Savigny, C.; Ladstätter-Weissenmayer, A.; Bötel, S.; Weber, M.; Alexei, R.; Bovensmann, H.; Burrows, J.

    2012-04-01

    Satellite observations of tropospheric ozone are of critical importance in obtaining a global and more thorough knowledge of the phenomena affecting air quality. Tropospheric ozone has a significant adverse effect on the climate system. In the lower troposphere, during summer, it is a major constituent of photochemical smog and excess of it is toxic to the ecosystem, animal and man. It is equally known as a major oxidant and also involved in the production of other oxidants such as hydroxyl (OH) radicals. In the middle and upper troposphere, ozone acts as a greenhouse gas. The retrieval of tropospheric ozone from UV/VIS/NIR satellite spectrometer such as the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the ESA satellite Envisat is difficult because only about 10 % of the Total Ozone Column (TOC) is in the troposphere. In this analysis we present the retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations. This technique is a residual approach that involves the subtraction of the stratospheric ozone columns derived from the limb observations from the total ozone columns derived from the nadir observations. The stratospheric ozone columns were derived by integrating the stratospheric ozone profiles from the tropopause, which was obtained from the re-analyses data of the European Centre for Medium-Range Weather Forecasts (ECMWF) in 1.5o x 1.5o x 91 levels based on both the thermal definition of tropopause using the WMO lapse-rate criterion as well as the potential vorticity definition of the tropopause. The total ozone columns were on the other hand retrieved using the Weighting Function DOAS algorithm (WFDOAS) at the spectral window of 326.6 - 334.5 nm. Equally of importance in our analysis is the tropospheric ozone columns derived from the ozonesondes by integrating the tropospheric ozone profiles from the bottom to the top of the troposphere, which was determined from the

  5. Changes in tropospheric composition and air quality due to stratospheric ozone depletion.

    PubMed

    Solomon, Keith R; Tang, Xiaoyan; Wilson, Stephen R; Zanis, Prodromos; Bais, Alkiviadis F

    2003-01-01

    chemical composition of the atmosphere including aerosols will also have an impact. For example, tropospheric OH is the 'cleaning' agent of the troposphere. While increased UV-B increases the OH concentration, increases in concentration of gases like methane, carbon monoxide and volatile organic compounds will act as sinks for OH in troposphere and hence change air quality and chemical composition in the troposphere. Also, changes in the aerosol content of the atmosphere resulting from global climate change may affect ozone photolysis rate coefficients and hence reduce or increase tropospheric ozone concentrations. PMID:12659540

  6. Tropospheric Ozone as a Short-lived Chemical Climate Forcer

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.

    2012-01-01

    Tropospheric ozone is the third most important greenhouse gas according to the most recent IPCC assessment. However, tropospheric ozone is highly variable in both space and time. Ozone that is located in the vicinity of the tropopause has the greatest effect on climate forcing. Nitrogen oxides (NOx) are the most important precursors for ozone In most of the troposphere. Therefore, pollution that is lofted upward in thunderstorm updrafts or NOx produced by lightning leads to efficient ozone production in the upper troposphere, where ozone is most important climatically. Global and regional model estimates of the impact of North American pollution and lightning on ozone radiative forcing will be presented. It will be shown that in the Northern Hemisphere summer, the lightning effect on ozone radiative forcing can dominate over that of pollution, and that the radiative forcing signal from North America extends well into Europe and North Africa. An algorithm for predicting lightning flash rates and estimating lightning NOx emissions is being incorporated into the NASA GEOS-5 Chemistry and Climate Model. Changes in flash rates and emissions over an ENSO cycle and in future climates will be assessed, along with the resulting changes in upper tropospheric ozone. Other research on the production of NOx per lightning flash and its distribution in the vertical based on cloud-resolving modeling and satellite observations will be presented. Distributions of NO2 and O3 over the Middle East from the OMI instrument on NASA's Aura satellite will also be shown.

  7. Contrasting fast precipitation responses to tropospheric and stratospheric ozone forcing

    NASA Astrophysics Data System (ADS)

    MacIntosh, C. R.; Allan, R. P.; Baker, L. H.; Bellouin, N.; Collins, W.; Mousavi, Z.; Shine, K. P.

    2016-02-01

    The precipitation response to radiative forcing (RF) can be decomposed into a fast precipitation response (FPR), which depends on the atmospheric component of RF, and a slow response, which depends on surface temperature change. We present the first detailed climate model study of the FPR due to tropospheric and stratospheric ozone changes. The FPR depends strongly on the altitude of ozone change. Increases below about 3 km cause a positive FPR; increases above cause a negative FPR. The FPR due to stratospheric ozone change is, per unit RF, about 3 times larger than that due to tropospheric ozone. As historical ozone trends in the troposphere and stratosphere are opposite in sign, so too are the FPRs. Simple climate model calculations of the time-dependent total (fast and slow) precipitation change, indicate that ozone's contribution to precipitation change in 2011, compared to 1765, could exceed 50% of that due to CO2 change.

  8. Transport effects on the vertical distribution of tropospheric ozone over western India

    NASA Astrophysics Data System (ADS)

    Lal, S.; Venkataramani, S.; Chandra, N.; Cooper, O. R.; Brioude, J.; Naja, M.

    2014-08-01

    In situ tropospheric ozone measurements by balloon-borne electrochemical concentration cell (ECC) sensors above Ahmedabad in western India from May 2003 to July 2007 are presented, along with an analysis of the transport processes responsible for the observed vertical ozone distribution. This analysis is supported by 12 day back trajectory calculations using the FLEXPART Lagrangian particle dispersion model. Lowest ozone (~20 ppbv) is observed near the surface during September at the end of the Asian summer monsoon season. Average midtropospheric (5-10 km above sea level) ozone is greatest (70-75 ppbv) during April-June and lowest (40-50 ppbv) during winter. Ozone variability is greatest in the upper troposphere with higher ozone during March-May. The FLEXPART retroplume results show that the free tropospheric vertical ozone distribution above this location is affected by long-range transport from the direction of North Africa and North America. Ozone levels are also affected by transport from the stratosphere particularly during March-April. The lower tropospheric (<3 km) ozone distribution during the Asian summer monsoon is affected by transport from the Indian Ocean via the east coast of Africa and the Arabian Sea. Influence from deep convection in the upper troposphere confined over central Asia has been simulated by FLEXPART. Lower ozone levels are observed during August-November than in any other season at 10-14 km above sea level. These in situ observations are in contrast to other studies based on satellite data which show that the lowest ozone values at these altitudes occur during the Asian summer monsoon.

  9. Present and future impact of aircraft, road traffic and shipping emissions on global tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Koffi, B.; Szopa, S.; Cozic, A.; Hauglustaine, D.; van Velthoven, P.

    2010-06-01

    In this study, the LMDz-INCA climate-chemistry model and up-to-date global emission inventories are used to investigate the "present" (2000) and future (2050) impacts of transport emissions (road traffic, shipping and aircraft) on global tropospheric ozone. For the first time, both impacts of emissions and climate changes on transport-induced ozone are investigated. The 2000 transport emissions are shown to mainly affect ozone in the Northern Hemisphere, with a maximum increase of the tropospheric column of up to 5 DU, from the South-Eastern US to Central Europe. The impact is dominated by road traffic in the middle and upper troposphere, north of 40° S, and by shipping in the northern lower troposphere, over oceanic regions. A strong reduction of road emissions and amoderate (B1 scenario) to high (A1B scenario) increase of the ship and aircraft emissions are expected by the year 2050. As a consequence, LMDz-INCA simulations predict a drastic decrease in the impact of road emissions, whereas aviation would become the major transport perturbation on tropospheric ozone, even in the case of avery optimistic aircraft mitigation scenario. The A1B emission scenario leads to an increase of the impact of transport on zonal mean ozone concentrations in 2050 by up to +30% and +50%, in the Northern and Southern Hemispheres, respectively. Despite asimilar total amount of global NOx emissions by the various transport sectors compared to 2000, the overall impact on the tropospheric ozone column is increased everywhere in 2050, due to a sectoral shift in the emissions of the respective transport modes. On the opposite, the B1 mitigation scenario leads to asignificant reduction (by roughly 50%) of the ozone perturbation throughout the troposphere compared to 2000. Considering climate change, and according to scenario A1B, a decrease of the O3 tropospheric burden is simulated by 2050 due to climate change (-1.2%), whereas an increase of ozone of up to 2% is calculated in the upper

  10. Present and future impact of aircraft, road traffic and shipping emissions on global tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Koffi, B.; Szopa, S.; Cozic, A.; Hauglustaine, D.; van Velthoven, P.

    2010-12-01

    In this study, the LMDz-INCA climate-chemistry model and up-to-date global emission inventories are used to investigate the "present" (2000) and future (2050) impacts of transport emissions (road traffic, shipping and aircraft) on global tropospheric ozone. For the first time, both impacts of emissions and climate changes on transport-induced ozone are investigated. The 2000 transport emissions are shown to mainly affect ozone in the Northern Hemisphere, with a maximum increase of the tropospheric column of up to 5 DU, from the South-eastern US to Central Europe. The impact is dominated by road traffic in the middle and upper troposphere, North of 40° S, and by shipping in the northern lower troposphere, over oceanic regions. A strong reduction of road emissions and a moderate (B1 scenario) to high (A1B scenario) increase of the ship and aircraft emissions are projected by the year 2050. As a consequence, LMDz-INCA simulations predict a drastic decrease in the impact of road emissions, whereas aviation would become the major transport perturbation on tropospheric ozone, even in the case of a very optimistic aircraft mitigation scenario. The A1B emission scenario leads to an increase of the impact of transport on zonal mean ozone concentrations in 2050 by up to +30% and +50%, in the Northern and Southern Hemispheres, respectively. Despite a similar total amount of global NOx emissions by the various transport sectors compared to 2000, the overall impact on the tropospheric ozone column is increased everywhere in 2050, due to a sectoral shift in the emissions of the respective transport modes. On the opposite, the B1 mitigation scenario leads to a significant reduction (by roughly 50%) of the ozone perturbation throughout the troposphere compared to 2000. Considering climate change, and according to scenario A1B, a decrease of the O3 tropospheric burden is simulated by 2050 due to climate change (-1.2%), whereas an increase of ozone of up to 2% is calculated in the

  11. Ozone in the Pacific Troposphere from Ozonesonde Observations

    NASA Technical Reports Server (NTRS)

    Oltmans, S. J.; Johnson, B. J.; Harris, J. M.; Voemel, H.; Koshy, K.; Simon, P.; Bendura, R.; Thompson, A. M.; Logan, J. A.; Hasebe, F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Ozone vertical profile measurements obtained from ozonesondes flown at Fiji, Samoa, Tahiti and the Galapagos are used to characterize ozone in the troposphere over the tropical Pacific. There is a significant seasonal variation at each of these sites. At sites in both the eastern and western Pacific, ozone is highest at almost all levels in the troposphere during the September-November season and lowest during, March-May. There is a relative maximum at all of the sites in the mid-troposphere during all seasons of the year (the largest amounts are usually found near the tropopause). This maximum is particularly pronounced during, the September-November season. On average, throughout the troposphere at all seasons, the Galapagos has larger ozone amounts than the western Pacific sites. A trajectory climatology is used to identify the major flow regimes that are associated with the characteristic ozone behavior at various altitudes and seasons. The enhanced ozone seen in the mid-troposphere during September-November is associated with flow from the continents. In the western Pacific this flow is usually from southern Africa (although 10-day trajectories do not always reach the continent), but also may come from Australia and Indonesia. In the Galapagos the ozone peak in the mid-troposphere is seen in flow from the South American continent and particularly from northern Brazil. The time of year and flow characteristics associated with the ozone mixing ratio peaks seen in both the western and eastern Pacific suggest that these enhanced ozone values result from biomass burning. In the upper troposphere low ozone amounts are seen with flow that originates in the convective western Pacific.

  12. The Response of Tropical Tropospheric Ozone to ENSO

    NASA Technical Reports Server (NTRS)

    Oman, L. D.; Ziemke, J. R.; Douglass, A. R.; Waugh, D. W.; Lang, C.; Rodriguez, J. M.; Nielsen, J. E.

    2011-01-01

    We have successfully reproduced the Ozone ENSO Index (OEI) in the Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) forced by observed sea surface temperatures over a 25-year period. The vertical ozone response to ENSO is consistent with changes in the Walker circulation. We derive the sensitivity of simulated ozone to ENSO variations using linear regression analysis. The western Pacific and Indian Ocean region shows similar positive ozone sensitivities from the surface to the upper troposphere, in response to positive anomalies in the Nino 3.4 Index. The eastern and central Pacific region shows negative sensitivities with the largest sensitivity in the upper troposphere. This vertical response compares well with that derived from SHADOZ ozonesondes in each region. The OEI reveals a response of tropospheric ozone to circulation change that is nearly independent of changes in emissions and thus it is potentially useful in chemistry-climate model evaluation.

  13. Improved Tropospheric Ozone Residual and Comparisons to the GMI Model

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Douglass, A. R.; Joiner, J.; Ziemke, G.; Duncan, B.; Stahan, S. E.

    2008-12-01

    Our tropospheric ozone residual (TOR) is produced by subtracting the stratospheric ozone column measured by MLS and the tropospheric ozone column measured by OMI. In our approach we use backward and forward trajectories from four days of MLS V2.2 measurements to boost the horizontal resolution of the stratospheric ozone field. The MLS stratospheric column is then subtracted from the OMI Col. 3 total ozone column. High reflectivity scenes (clouds) are no longer discarded - the OMI cloud pressure and radiative cloud fraction is used to adjust the surface pressure to the cloud centroid pressure. The subsequent TOR fields are validated by comparing them to ozonesondes. Our TOR fields show a 0.8 correlation to sonde columns; a clear improvement over earlier calculations. OMI-MLS TOR from 2005 and 2006 are compared with the Global Modeling Initiative (GMI) derived tropospheric column. The results show that the OMI-MLS TOR underestimates the tropospheric column. GMI tropospheric column and OMI-MLS TOR compare better if the lowest 1.5 km of the GMI column is excluded. This is consistent with a global -7 DU low offset from the sonde columns that is probably due to lack of OMI boundary layer ozone sensitivity. The GMI model zonal distribution also shows relatively higher tropospheric columns at mid latitudes and lower column amounts at high latitudes compared to the OMI-MLS TOR.

  14. Quantifying Isentropic Stratosphere-Troposphere Exchange (STE) of Ozone

    NASA Astrophysics Data System (ADS)

    Yang, H.; Chen, G.; Tang, Q.; Hess, P. G. M.

    2014-12-01

    There is increasing evidence showing that stratosphere-troposphere exchange (STE) of ozone can have a significant impact on the interannual variability and long- term trend of the tropospheric chemistry and radiation budget. Traditional diagnostics of STE ozone flux consider the ozone budget of the lowermost stratosphere by coupling the residual circulation and ozone. However, this method can only provide information of the hemispheric mean ozone flux, and therefore it does not distinguish the exchange of ozone into the tropics from the exchange of ozone into the midlatitudes that may have different tropospheric impacts. This present study extends the traditional approach from the entire lowermost stratosphere to individual isentropic layers in the lower stratosphere, and therefore distinguishes the meridional location of STE. The specified dynamics (SD) version of the Whole Atmosphere Community Climate Model (WACCM) is used for the estimate of isentropic STE flux. The diagnosed meridional structure of ozone flux is generally consistent with studies with other methods (e.g., tracer trajectories or the budget of tropospheric ozone). Different seasonal cycles of ozone STE are found at different isentropic surfaces, emphasizing different tropospheric impacts from ozone STE over different meridional regions. For isentropes between 350K and 380K, net troposphere-to-stratosphere ozone STE flux peaks in summer. For isentropes between 330K and 350K, the net ozone STE flux peaks in summer too, but it is from stratosphere to troposphere. For isentropes between 280K and 330K, larger net stratosphere-to-troposphere ozone STE flux is found in the Northern Hemisphere and peaks in spring, whereas little seasonal variability is detected in the Southern Hemisphere. Furthermore, the diagnostic enables a partition that links the variability in the STE flux to specific dynamic processes. In particular, the air mass STE flux component associated with the isentropic mixing is found

  15. Impact of Stratospheric Ozone Zonal Asymmetries on the Tropospheric Circulation

    NASA Technical Reports Server (NTRS)

    Tweedy, Olga; Waugh, Darryn; Li, Feng; Oman, Luke

    2015-01-01

    The depletion and recovery of Antarctic ozone plays a major role in changes of Southern Hemisphere (SH) tropospheric climate. Recent studies indicate that the lack of polar ozone asymmetries in chemistry climate models (CCM) leads to a weaker and warmer Antarctic vortex, and smaller trends in the tropospheric mid-latitude jet and the surface pressure. However, the tropospheric response to ozone asymmetries is not well understood. In this study we report on a series of integrations of the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to further examine the effect of zonal asymmetries on the state of the stratosphere and troposphere. Integrations with the full, interactive stratospheric chemistry are compared against identical simulations using the same CCM except that (1) the monthly mean zonal mean stratospheric ozone from first simulation is prescribed and (2) ozone is relaxed to the monthly mean zonal mean ozone on a three day time scale. To analyze the tropospheric response to ozone asymmetries, we examine trends and quantify the differences in temperatures, zonal wind and surface pressure among the integrations.

  16. AN APPROACH FOR CHARACTERIZING TROPOSPHERIC OZONE RISK TO FOREST

    EPA Science Inventory

    The risk tropospheric ozone poses to forests in the United States is dependent on the variation in ozone exposure across the distribution of the forests in question and the various environmental and climate factors predominant in the region. All these factors have a spatial natur...

  17. Discoveries about Tropospheric Ozone Pollution from Satellite and Soundings

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.

    2004-01-01

    We have been producing near-red time tropospheric ozone satellite maps from the TOMS (Total Ozone Mapping Spectrometer) sensor since 1997. Maps for 1996-2000 for the operational Earth-Probe instrument are at:. Pollution in the tropics is influenced by biomass burning and by transport patterns that favor recirculation and in other cases reflect climate variability like the El-Nino-Southern Oscillation [Thompson et al., 2001]. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical gradients in pollution. Thus, in 1998, NASA's Goddard Space Flight Center and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches and provides a public archive of ozonesonde data from twelve tropical stations at http://croc.gsfc.nasa.gov/shadoz. Further insights into the role of chemical and dynamical influences have emerged from the first 4-5 years of SHADOZ data (more than 2000 ozone profiles). Highly variable tropospheric ozone and a zonal wave-one pattern in tropospheric ozone suggest that dynamics is as important as pollution in determining tropical ozone distributions.

  18. Processes Affecting Tropospheric Ozone Inferred from Ozonesonde and Other Tracer Data from the R/V R H Brown Atlantic Cruise (37N-34S) in January-February 1999

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Doddridge, B. G.; Luke, W. T.; Johnson, J. E.; Witte, J. C.; Reynolds, R. M.; Johnson, B.; Oltmans, S. J.

    1999-01-01

    During the Aerosols-99 trans-Atlantic cruise from Norfolk, VA, to Cape Town, South Africa, 22 ozonesondes were launched from the NOAA R/V R H Brown between 17 Jan and 6 Feb 1999, with all sondes but one reaching 30 km. A composite of ozone profiles along the transect shows high free tropospheric ozone (up to 100 ppbv at 9 km) between 5N and 20S, a coherent feature straddling either side of the ITCZ. Latitudinal variations of tropospheric ozone are interpreted using correlative measurements of surface ozone, CO, water vapor, and aerosol optical thickness (column absorbance) measured from the ship. Elevated ozone in the lower troposphere results from photochemical reactions of precursors emitted by biomass burning north of the ITCZ. However, the greatest ozone mixing ratios are in the mid-troposphere south of the ITCZ, which gives evidence of interhemispheric transport. Column-integrated tropospheric ozone, 35 DU from 0-16 km, agrees with that derived from the TOMS satellite by the modified-residual method [Thompson and Hudson, 1999]. NCEP wind fields, ship-launched radiosondes and back trajectories are consistent with a picture of recirculating air parcels centered in the tropical Atlantic region which is identified with the maximum wave-one amplitude in total ozone seen in sondes and by satellite.

  19. Tropospheric ozone at 45 deg S

    NASA Technical Reports Server (NTRS)

    Matthews, W. Andrew

    1994-01-01

    In August of 1986 a program was initiated to measure atmospheric ozone profiles at mid-latitudes in the Southern Hemisphere by flying ECC ozonesondes on a regular basis from the DSIR Physical Sciences Atmospheric Laboratory at Lauder, New Zealand, 45 deg S. Flights since that time have been performed on a regular basis at the rate of two flights per week during the 5 month period August to December, the time of maximum variability at mid-latitudes, and once per week for the remainder of the year. These data, consisting now of more than 400 profiles has been analyzed and the free troposphere portion of the profiles binned as 1km slabs. These data have been combined to form a seasonal average values for each season of each year in 2 km slabs and the variation observed in these seasonal averages is the basis of this paper. A biennial component is apparent in these data and the lack of any increasing trend over this 5 year period is contrasted with that measured at similar latitudes in the Northern Hemisphere over the same period.

  20. Decrease of summer tropospheric ozone concentrations in Antarctica

    NASA Technical Reports Server (NTRS)

    Schnell, R. C.; Stone, R. S.; Liu, S. C.; Oltmans, S. J.; Hofmann, D. J.

    1991-01-01

    It is shown here that surface ozone concentrations at the South Pole in the austral summer decreased by 17 percent over the period 1976-90. Over the same period, solar irradiance at the South Pole in January and February decreased by 7 percent as a result of a 25 percent increase in cloudiness. It is suggested that the trend in the summer ozone concentrations is caused by enhanced photochemical destruction of ozone in the lower troposphere caused by the increased penetration of UV radiation associated with stratospheric ozone depletion, coupled with enhanced transport of ozone-poor marine air from lower latitudes to the South Pole.

  1. Tropospheric ozone based on satellite measurements of sciamachy and gome

    NASA Astrophysics Data System (ADS)

    Ladstaetter-Weissenmayer, A.; v. Savigny, C.; Sierks, B.; Burrows, J. P.; Richter, A.; Wittrock, F.

    2003-04-01

    The increase of pollution events caused by an accession of population leads an to extensive air quality degradation with regional and global implications. During such events high levels of trace gases like methane (CH4), carbon monoxid (CO), non methane hydrocarbons (NMHC) and nitrogen oxides (NOx= NO+NO2) can be observed. Additionally tropospheric ozone (O3) is produced by photochemical processes as well. Tropospheric O3 itself is a trace gas, which plays a controlling role in the oxidation capacity of the atmosphere. Until recently our knowledge of the distribution of tropospheric O3 has come from ozone sondes, surface and aircraft observations only, but since the launch of satellite experiments such as GOME (Global Ozone Monitoring Experiment, 1995) and SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY, 2002) their measurement data allow the globally analysis of tropospheric O3.

  2. The global consequences of increasing tropospheric ozone concentrations

    NASA Technical Reports Server (NTRS)

    Fishman, Jack

    1989-01-01

    Recent analyses of long term records of tropospheric ozone measurements in the Northern Hemisphere suggest that it is increasing at a rate of 1 to 2 percent per year. Because of this, it is argued that the amount of atmospheric warming due to increasing tropospheric ozone is comparable to, or possibly even greater than, the amount of warming due to the increase of carbon dioxide. Unlike all other climatically important trace gases, ozone is toxic, and increases in its concentration will result in serious environmental damage, as well as impairment of human health.

  3. The global consequences of increasing tropospheric ozone concentrations

    NASA Technical Reports Server (NTRS)

    Fishman, Jack

    1991-01-01

    Recent analyses of long-term records of tropospheric ozone measurements in the Northern Hemisphere suggest that it is increasing at a rate of 1 to 2 percent per year. Because of this, it is argued that the amount of atmospheric warming due to increasing tropospheric ozone is comparable to, or possibly even greater than, the amount of warming due to the increase of carbon dioxide. Unlike all other climatically important trace gases, ozone is toxic, and increases in its concentration will result in serious environmental damage, as well as impairment of human health.

  4. Tropical Tropospheric Ozone Climatology: Approaches Based on SHADOZ Observations

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Chatfield, Robert B.; Hudson, Robert D.; Andrade, Marcos; Coetzee, Geert J. R.; Posny, Francoise

    2004-01-01

    The SHADOZ (Southern Hemisphere Additional Ozonesondes) ozone sounding network was initiated in 1998 to improve the coverage of tropical in-situ ozone measurements for satellite validation, algorithm development and related process studies. Over 2000 soundings have been archived at the central website, , for 12 stations that span the entire equatorial zone [Thompson et al., JGR, 108,8238, 2003]. The most striking features of tropospheric ozone profiles in SHADOZ are: (1) persistent longitudinal variability in tropospheric ozone profiles, with a 10-15 DU column-integrated difference between Atlantic and Pacific sites; (2) intense short-term variability triggered by changing meteorological conditions and advection of pollution. The implications of these results for profile climatologies and trends are described along with several approaches to classifying ozone profiles: 1) Seasonal means during MAM (March-April-May) and SON (September-October-November); 2) Maxima and minima, identified through correlation of TOMS-derived TTO (tropical tropospheric ozone) column depth with the sonde integrated tropospheric ozone column; and 3) Meteorological regimes, a technique that is effective in the subtropics where tropical and mid-latitude conditions alternate.

  5. Tropospheric ozone climatology over Peninsular Malaysia from 1992 to 1999

    NASA Astrophysics Data System (ADS)

    Yonemura, Seiichiro; Tsuruta, Haruo; Kawashima, Shigeto; Sudo, Shigeto; Peng, Leong Chow; Fook, Lim Sze; Johar, Zubaidi; Hayashi, Masayasu

    2002-08-01

    We present the climatology of tropospheric ozone over Peninsular Malaysia in tropical Asia for the 8 years from 1992 through 1999 as measured by ozonesondes twice a month. The mean ozone concentrations in vertical profile were in the same range (30-40 ppbv) as those observed at Watukosek, Indonesia, and were lower than those at Natal, Brazil, South America, and at Brazzaville, Congo, Africa, indicating that air masses over Peninsular Malaysia are primarily influenced by the maritime environment and deep convection, as shown by the significant levels of water vapor in the middle troposphere throughout the year. Seasonally averaged ozone concentrations were highest in December, January, and February (DJF) from 6 to 7.5 km altitude and in March, April, and May (MAM) at all other heights and were lowest in June, July, and August (JJA) and September, October, and November (SON), excluding 1994 and 1997, at all heights. The ozone enhancements during DJF in the middle troposphere could be caused by depression of the deep convection because of the positive temperature anomaly and negative water vapor anomaly. The ozone enhancements above the middle troposphere (>5 km) in MAM, especially in 1997 and 1998, could be predominantly attributed to photochemical production from enhanced ozone precursor gases of Northern Hemisphere origin, especially biomass burning in continental Southeast Asia. Large ozone enhancements as high as 10-20 Dobson units observed during SON of 1994 and 1997 were associated with large-scale biomass burnings in Indonesia.

  6. Tropospheric Ozone Over the North Pacific from Ozonesdonde Observations

    NASA Technical Reports Server (NTRS)

    Oltmans, S. J.; Johnson, B. J.; Harris, J. M.; Thompson, A. M.; Liu, H. Y.; Voemel, H.; Chan, C. Y.; Fujimoto, T.; Brackett, V. G.; Chang, W. L.

    2003-01-01

    As part of the TRACE-P mission, ozone vertical profile measurements were made at a number of locations in the North Pacific. At most of the sites there is also a multi-year record of ozonesonde observations. From seven locations in the western Pacific (Hong Kong; Taipei; Jeju Island, Korea; and Naha, Kagoshima, Tsukuba, and Sapporo, Japan), a site in the central Pacific (Hilo, HI), and a site on the west coast of the U.S. (Trinidad Head, CA) both a seasonal and event specific picture of tropospheric ozone over the North Pacific emerges. At all of the sites there is a pronounced spring maximum through the troposphere. There are, however, differences in the timing and strength of this feature. Over Japan the northward movement of the jet during the spring and summer influences the timing of the seasonal maximum. The ozone profiles suggest that transport of ozone rich air from the stratosphere plays a strong role in the development of this maximum. During March and April at Hong Kong ozone is enhanced in a layer that extends from the lower free troposphere into the upper troposphere that likely has its origin in biomass burning in northern Southeast Asia and equatorial Africa. During the winter the Pacific subtropical sites (latitude -25N) are dominated by air with a low-latitude, marine source that gives low ozone amounts particularly in the upper troposphere. In the summer in the boundary layer at all of the sites marine air dominates and ozone amounts are generally quite low (less than 25 ppb). The exception is near large population centers (Tokyo and Taipei but not Hong Kong) where pollution events can give amounts in excess of 80 ppb. During the TRACE-P intensive campaign period (February-April 2001) tropospheric ozone amounts were rather typical of those seen in the long-term records of the stations with multi-year soundings.

  7. Lidar Measurements of Tropospheric Ozone in the Arctic

    NASA Astrophysics Data System (ADS)

    Seabrook, Jeffrey; Whiteway, James

    2016-06-01

    This paper reports on differential absorption lidar (DIAL) measurements of tropospheric ozone in the Canadian Arctic during springtime. Measurements at Eureka Weather Station revealed that mountains have a significant effect on the vertical structure of ozone above Ellesmere Island. Ozone depletion events were observed when air that had spent significant time near to the frozen surface of the Arctic Ocean reached Eureka. This air arrived at Eureka by flowing over the surrounding mountains. Surface level ozone depletions were not observed during periods when the flow of air from over the sea ice was blocked by mountains. In the case of blocking there was an enhancement in the amount of ozone near the surface as air from the mid troposphere descended in the lee of the mountains. Three case studies will be shown in the presentation, while one is described in this paper.

  8. Influence of tropical cyclones on tropospheric ozone: possible implications

    NASA Astrophysics Data System (ADS)

    Shankar Das, Siddarth; Venkat Ratnam, Madineni; Narasimhan Uma, Kizhathur; Venkata Subrahmanyam, Kandula; Asatar Girach, Imran; Patra, Amit Kumar; Aneesh, Sundaresan; Viswanathan Suneeth, Kuniyil; Kishore Kumar, Karanam; Parashuram Kesarkar, Amit; Sijikumar, Sivarajan; Ramkumar, Geetha

    2016-04-01

    The present study examines the role of tropical cyclones in the enhancement of tropospheric ozone. The most significant and new observation reported is the increase in the upper-tropospheric (10-16 km) ozone by 20-50 ppbv, which has extended down to the middle (6-10 km) and lower troposphere ( < 6 km). The descent rate of enhanced ozone layer during the passage of tropical cyclone is 0.8-1 km day-1, which is three times that of a clear-sky day (non-convective). Enhancement of surface ozone concentration by ˜ 10 ppbv in the daytime and 10-15 ppbv in the night-time is observed during a cyclone. Potential vorticity, vertical velocity and potential temperature obtained from numerical simulation, reproduces the key feature of the observations. A simulation study indicates the downward transport of stratospheric air into the troposphere. Space-borne observations of relative humidity indicate the presence of sporadic dry air in the upper and middle troposphere over the cyclonic region. These observations quantitatively constitute experimental evidence of redistribution of stratospheric ozone during cyclonic storms.

  9. The photochemistry of synoptic-scale ozone synthesis Implications for the global tropospheric ozone budget

    NASA Technical Reports Server (NTRS)

    Fishman, J.; Browell, E. V.; Vukovich, F. M.

    1985-01-01

    The oxidation of nonmethane hydrocarbons represents a source of tropospheric ozone that is primarily confined to the boundary layers of several highly industrialized regions. (Each region has an area greater than one million km/sq cm). Using a photochemical model, the global tropospheric ozone budget is reexamined by including the in-situ production from these localized regimes. The results from these calculations suggest that the net source due to this photochemistry, which takes place on the synoptic scale, is approximately as large as the amount calculated for global scale photochemical processes which consider only the oxidation of methane and carbon monoxide. Such a finding may have a considerable impact on our understanding of the tropospheric ozone budget. The model results for ozone show reasonable agreement with the climatological summer distribution of ozone and the oxides of nitrogen at the surface and with the vertical distribution of ozone and nonmethane hydrocarbons obtained during a 1980 field program.

  10. Subtropical Potential Vorticity Intrusion Drives Increasing Tropospheric Ozone over the Tropical Central Pacific

    PubMed Central

    Nath, Debashis; Chen, Wen; Graf, Hans-F.; Lan, Xiaoqing; Gong, Hainan; Nath, Reshmita; Hu, Kaiming; Wang, Lin

    2016-01-01

    Drawn from multiple reanalysis datasets, an increasing trend and westward shift in the number of Potential Vorticity intrusion events over the Pacific are evident. The increased frequency can be linked to a long-term trend in upper tropospheric equatorial westerly wind and subtropical jets during boreal winter to spring. These may be resulting from anomalous warming and cooling over the western Pacific warm pool and the tropical eastern Pacific, respectively. The intrusions brought dry and ozone rich air of stratospheric origin deep into the tropics. In the tropical upper troposphere, interannual ozone variability is mainly related to convection associated with El Niño/Southern Oscillation. Zonal mean stratospheric overturning circulation organizes the transport of ozone rich air poleward and downward to the high and midlatitudes leading there to higher ozone concentration. In addition to these well described mechanisms, we observe a long-term increasing trend in ozone flux over the northern hemispheric outer tropical (10–25°N) central Pacific that results from equatorward transport and downward mixing from the midlatitude upper troposphere and lower stratosphere during PV intrusions. This increase in tropospheric ozone flux over the Pacific Ocean may affect the radiative processes and changes the budget of atmospheric hydroxyl radicals. PMID:26868836

  11. Subtropical Potential Vorticity Intrusion Drives Increasing Tropospheric Ozone over the Tropical Central Pacific.

    PubMed

    Nath, Debashis; Chen, Wen; Graf, Hans-F; Lan, Xiaoqing; Gong, Hainan; Nath, Reshmita; Hu, Kaiming; Wang, Lin

    2016-01-01

    Drawn from multiple reanalysis datasets, an increasing trend and westward shift in the number of Potential Vorticity intrusion events over the Pacific are evident. The increased frequency can be linked to a long-term trend in upper tropospheric equatorial westerly wind and subtropical jets during boreal winter to spring. These may be resulting from anomalous warming and cooling over the western Pacific warm pool and the tropical eastern Pacific, respectively. The intrusions brought dry and ozone rich air of stratospheric origin deep into the tropics. In the tropical upper troposphere, interannual ozone variability is mainly related to convection associated with El Niño/Southern Oscillation. Zonal mean stratospheric overturning circulation organizes the transport of ozone rich air poleward and downward to the high and midlatitudes leading there to higher ozone concentration. In addition to these well described mechanisms, we observe a long-term increasing trend in ozone flux over the northern hemispheric outer tropical (10-25°N) central Pacific that results from equatorward transport and downward mixing from the midlatitude upper troposphere and lower stratosphere during PV intrusions. This increase in tropospheric ozone flux over the Pacific Ocean may affect the radiative processes and changes the budget of atmospheric hydroxyl radicals. PMID:26868836

  12. Subtropical Potential Vorticity Intrusion Drives Increasing Tropospheric Ozone over the Tropical Central Pacific

    NASA Astrophysics Data System (ADS)

    Nath, Debashis; Chen, Wen; Graf, Hans-F.; Lan, Xiaoqing; Gong, Hainan; Nath, Reshmita; Hu, Kaiming; Wang, Lin

    2016-02-01

    Drawn from multiple reanalysis datasets, an increasing trend and westward shift in the number of Potential Vorticity intrusion events over the Pacific are evident. The increased frequency can be linked to a long-term trend in upper tropospheric equatorial westerly wind and subtropical jets during boreal winter to spring. These may be resulting from anomalous warming and cooling over the western Pacific warm pool and the tropical eastern Pacific, respectively. The intrusions brought dry and ozone rich air of stratospheric origin deep into the tropics. In the tropical upper troposphere, interannual ozone variability is mainly related to convection associated with El Niño/Southern Oscillation. Zonal mean stratospheric overturning circulation organizes the transport of ozone rich air poleward and downward to the high and midlatitudes leading there to higher ozone concentration. In addition to these well described mechanisms, we observe a long-term increasing trend in ozone flux over the northern hemispheric outer tropical (10-25°N) central Pacific that results from equatorward transport and downward mixing from the midlatitude upper troposphere and lower stratosphere during PV intrusions. This increase in tropospheric ozone flux over the Pacific Ocean may affect the radiative processes and changes the budget of atmospheric hydroxyl radicals.

  13. Analysis of Satellite Remote Sensing Observations of Low Ozone Events in the Tropical Upper Troposphere and Links with Convection

    NASA Astrophysics Data System (ADS)

    Cooper, M.; Martin, R.; Livesey, N. J.; Degenstein, D. A.; Walker, K. A.

    2013-12-01

    Ozone is an important contributor to upper tropospheric oxidation processes and radiative forcing. Upper tropospheric ozone is greatly affected by convection, particularly in the tropics. Deep convection in the maritime tropics is believed to bring air with low ozone concentrations from the surface to the upper troposphere causing reduced ozone concentrations aloft. Satellite observations from three instruments (MLS, OSIRIS, ACE-FTS) reveal coherent patterns of low ozone events (<20 ppb) in the tropical upper troposphere. Using a chemical transport model (GEOS-Chem) we find that these events result from deep convective processes that rapidly transport air with low ozone concentrations from the marine boundary layer. These events occur with greater frequency over the tropical South Pacific warm pool, which is consistent with ozonesonde observations. The satellite observations indicate spatial shifts in the frequency of low ozone events that we attribute to changes in convection. Interannual convective variability is driven by the El Nino Southern Oscillation. We find that as the location of the warm pool shifts eastward during El Niño events, the location of the most frequent low ozone events in the satellite record follows. Mapping of low ozone events over time reveals eastward propagating systems resembling the Madden-Julian Oscillation. These observations and analyses strengthen the link between deep convection and ozone concentrations in the tropical upper troposphere.

  14. Tropospheric Ozone Pollution from Space: New Views from the TOMS (Total Ozone Mapping Spectrometer) Instrument

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Hudson, Robert D.; Frolov, Alexander D.; Witte, Jacquelyn C.; Kucsera, Tom L.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    New products from the TOMS (Total Ozone Mapping Spectrometer) >satellite instrument can resolve pollution events in tropical and mid-latitudes, Over the past several years, we have developed tropospheric ozone data sets by two methods. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMSdirect method [Hudson et at., 2000] represents a new algorithm that uses TOMS radiances to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution, Absorbing aerosols (dust and smoke; Herman et at., 1997 Hsu et al., 1999), a standard TOMS product, provide transport and/or source marker information to interpret tropospheric ozone. For the Nimbus 7/TOMS observing period (1979-1992), modified-residual TTO (tropical tropospheric ozone) appears as two maps/month at I-degree latitude 2-degree longitude resolution at a homepage and digital data are available (20S to 20N) by ftp at http://metosrv2. umd.edu/tropo/ 14y_data.d. Preliminary modified-residual TTO data from the operational Earth-Probe/TOMS (1996- present) are posted in near-real-time at the same website. Analyses with the new tropospheric ozone and aerosol data are illustrated by the following (I)Signals in tropical tropospheric ozone column and smoke amount during ENSO (El Nino-Southern Oscillation) events, e.g. 1982-1983 and the intense ENSO induced biomass fires of 1997-1998 over the Indonesian region [Thompson et a[, 2000a, Thompson and Hudson, 1999]. (2) Trends in tropospheric ozone and smoke aerosols in various tropical regions (Atlantic, Pacific, Africa, Brazil). No significant trends were found for ozone from1980-1990 [Thompson and Hudson, 19991 although smoke aerosols increased during the period [Hsu et al.,1999]. (3) Temporal and spatial offsets

  15. Tropospheric Ozone from limb nadir matching of MIPAS and SCIAMACHY

    NASA Astrophysics Data System (ADS)

    Rahpoe, Nabiz; Ebojie, Felix; Jia, Jia; Weber, Mark; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.; von Clarmann, Thomas; Stiller, Gabriele; Laeng, Alexandra; Lossow, Stefan

    2016-04-01

    The tropospheric total ozone column (TTOC) is retrieved by applying the limb nadir matching method (LNM) for two different sensors on board the Envisat satellite. Each sensor provides independent information of the total ozone column (TOC, nadir) and stratospheric ozone column (SOC, limb). The latter is derived from the limb viewing geometry of MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), while total ozone column (TOC) from the nadir viewing SCIAMACHY (SCanning Imaging spectrometer for AtMospheric CHartrographY) measurements. The residual ozone column or tropospheric total ozone column (TTOC) is then derived by subtraction of the SOC from the collocated TOC. Although this method is straightforward, the underlying difficulties are the exact knowledge of the tropopause height, matching/collocation of the two measurements, and instrumental differences between two sensors. Our results are compared with available tropospheric ozone columns derived from the SCIAMACHY - SCIAMACHY limb-nadir combination in order to understand the differences and the potential of LNM method for different sensor combination.

  16. Tropospheric ozone pool over Arabian sea during pre-monsoon

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Ladstätter-Weißenmayer, Annette; Hou, Xuewei; Rozanov, Alexei; Burrows, John

    2016-04-01

    This study focuses on the remarkable and stable phenomenon-enhancement of the tropospheric ozone over Arabian Sea (AS) during the pre-monsoon season. Satellite data (SCIAMACHY LNM, OMI/MLS and TES) showed a strong and clear ozone seasonality over AS with ~42 DU maxima in pre-monsoon season. With the help of MACC reanalysis data, our results showed that 3/4 of the enhanced ozone during this season is contributed at 0-8 km height. The main source of the ozone enhancement is believed to be a long range transport, together with a suitable meteorological condition for pollution accumulation. Local chemistry plays different roles over different altitudes. However we believe the contribution to the tropospheric ozone enhancement from the chemistry is low. The contribution of the STE is unclear. In addition, the interannual variation of the pre-monsoon tropospheric ozone enhancement over AS is discussed. The anomalies in 2005 and 2010 could be due to the dynamical variation of ozone caused by the El Niño events.

  17. Recent Changes in Tropospheric Ozone in the Tropics

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    This paper presents a detailed characterization of tropical tropospheric column ozone variability on time scales varying from a few days to a solar cycle. The study is based on more than 20 years (1979 to the present) of tropospheric column ozone time series derived from the convective cloud differential (CCD) method using total ozone mapping spectrometer (TOMS) data. Results indicate three distinct regions in the tropics with distinctly three different zonal characteristics related to seasonal, interannual and solar variabilities. These three regions are the eastern Pacific, Atlantic, and western Pacific. Tropospheric column ozone in the Atlantic region peaks at about the same time (September-October) from 20 N to 20 S. The amplitude of the annual cycle, however, varies from about 3 to 6 Dobson unit (DU) from north to south of the equator. In comparison, the annual cycle in both the eastern and western Pacific is generally week and the phase varies from peak values in March and April in the northern hemisphere to September and October in the southern hemisphere. The interannual pattern in the three regions are also very different. The Atlantic region indicates a quasi biennial oscillation in the tropospheric column ozone which is out of phase with the stratospheric ozone. This is consistent with the photochemical control of this region caused by high pollution and high concentration of ozone producing precursors. The observed pattern, however, does not seem to be related to the interannual variability in ozone precursors related to biomass burning. Instead, it appears to be a manifestation of the UV modulation of upper tropospheric chemistry on a QBO time scale caused by stratospheric ozone. During El Nino events, there is anomalously low ozone in the eastern Pacific and high values in the western Pacific indicating the effects of convectively driven transport. The observed increase of 10-20 DU in tropospheric column ozone in the Indonesian region in the western

  18. Towards the retrieval of tropospheric ozone with the Ozone Monitoring Instrument (OMI)

    NASA Astrophysics Data System (ADS)

    Mielonen, T.; de Haan, J. F.; van Peet, J. C. A.; Eremenko, M.; Veefkind, J. P.

    2015-02-01

    We have assessed the sensitivity of the operational Ozone Monitoring Instrument (OMI) ozone profile retrieval algorithm to a number of a priori and radiative transfer assumptions. We studied the effect of stray light correction, surface albedo assumptions and a priori ozone profiles on the retrieved ozone profile. Then, we studied how to modify the algorithm to improve the retrieval of tropospheric ozone. We found that stray light corrections have a significant effect on the retrieved ozone profile but mainly at high altitudes. Surface albedo assumptions, on the other hand, have the largest impact at the lowest layers. Choice of an ozone profile climatology which is used as a priori information has small effects on the retrievals at all altitudes. However, the usage of climatological a priori covariance matrix has a significant effect. Based on these sensitivity tests, we made several modifications to the retrieval algorithm: the a priori ozone climatology was replaced with a new tropopause-dependent climatology, the a priori covariance matrix was calculated from the climatological ozone variability values, and the surface albedo was assumed to be linearly dependent on wavelength in the 311.5-330 nm channel. As expected, we found that the a priori covariance matrix basically defines the vertical distribution of degrees of freedom for a retrieval. Moreover, our case study over Europe showed that the modified version produced over 10% smaller ozone abundances in the troposphere which reduced the systematic overestimation of ozone in the retrieval algorithm and improved correspondence with Infrared Atmospheric Sounding Instrument (IASI) retrievals. The comparison with ozonesonde measurements over North America showed that the operational retrieval performed better in the upper troposphere/lower stratosphere (UTLS), whereas the modified version improved the retrievals in the lower troposphere and upper stratosphere. These comparisons showed that the systematic biases

  19. Attribution of free tropospheric ozone over eastern China using TES ozone observations, NO2 OMI retrievals and the TM5 chemistry transport model

    NASA Astrophysics Data System (ADS)

    Verstraeten, Willem W.; (K. F.) Boersma, Folkert; Williams, Jason; Bowman, Kevin W.; Worden, John R.

    2014-05-01

    Tropospheric ozone is an important greenhouse gas and a global air pollutant originating from photo-chemical oxidation of precursors such as volatile organic compounds (VOCs) and CO in the presence of NOX in favouring meteorological conditions, long range transport and stratosphere-troposphere ozone exchange (STE). Assessing ozone trends in the troposphere remain difficult due to scarcity of long-term measurement sites, but spaceborne sensors can cope much better with that thanks to their spatio-temporal abilities. Today, eastern Asia has the fastest growing anthropogenic emissions. It has been suggested that much of this pollution is exported eastwards towards western North America affecting the local ozone concentrations in the troposphere. We analysis time series of free tropospheric ozone observed from space by TES (Tropospheric Emission Spectrometer onboard NASA's EOS-Aura satellite) over eastern China. Based on the TM5 chemical transport models (CTM) using six years (2005-2010) of model simulations we attribute the observations to the different sources of ozone using model runs with different anthropogenic emissions of NOX. Here we show a strong and rapid increase (~7 ppbv, or 10% per year) in free tropospheric ozone over China retrieved with the TES satellite instrument from 2005 to 2010. We attribute this increase to a larger inflow of stratospheric ozone and particularly to enhanced ozone production following highly significant increases in Chinese NOX emissions as observed with the OMI satellite instrument. Despite the emission reduction in the western United States, the observed ozone concentrations in the free troposphere raise, which is attributed to the increase of Chinese emissions.

  20. On the role of climate variability on tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Lin, M.

    2014-12-01

    The response of tropospheric ozone to changing atmospheric circulation is poorly understood owing to a lack of reliable long-term observations. There is great current interest in quantifying the extent to which observed ozone trends over recent decades at northern mid-latitude sites are driven by changes in precursor emissions versus shifts in atmospheric circulation patterns. In this talk, I present a detailed analysis of the impact of interannual to decadal climate variability on tropospheric ozone, based on observations and a suite of chemistry-climate model hindcast simulations. Decadal shifts in circulation regimes modulate long-range transport of Asian pollution, leading to very different seasonal ozone trends at Mauna Loa Observatory in the subtropical Pacific Ocean. During autumn, the flow of ozone-rich air from Eurasia towards Hawaii strengthened in the mid-1990s onwards, as a result of the positive phase of the Pacific North American pattern, increasing ozone at Mauna Loa. During spring, weakening airflow from Asia in the 2000s, tied to La-Niña-like decadal cooling in the equatorial Pacific Ocean, offsets ozone increases at Mauna Loa that otherwise would have occurred due to rising Asian emissions. The circulation-driven variability in Asian pollution over the subtropical North Pacific regions manifests mainly as changes in the mean as opposed to in transport events. At high-elevation Western U.S. sites, intrusions of stratospheric ozone deep into the troposphere during spring exert a greater influence than Asian pollution, particularly on the high tail of observed surface ozone distribution. We show that year-to-year variability in springtime high-ozone episodes measured in Western U.S. surface air is tied to known modes of climate variability, which modulate meanders in the polar frontal jet conducive to deep stratospheric ozone intrusions. Specifically, the La Niña-related increase in the frequency of deep stratospheric intrusion events plays a

  1. Ozone in the troposphere and stratosphere, part 2

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D. (Editor)

    1994-01-01

    This is the second of a 2-part Conference Publication. This document contains papers presented at the 1992 Quadrennial Ozone Symposium held at Charlottesville, Virginia, from June 4-13, 1992. The papers cover topics in both Tropospheric and Stratospheric research. These topics include ozone trends and climatology, ground based, aircraft, balloon, rocket and satellite measurements, Arctic and Antarctic research, global and regional modeling, and volcanic effects.

  2. Ozone in the Troposphere and Stratosphere, part 1

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D.

    1994-01-01

    This is the first part of a 2-part Conference Publication. This document contains papers presented at the 1992 Quadrennial Ozone Symposium held at the Charlottesville, Virginia, from June 4-13, 1992. The papers cover topics in both Tropospheric and Stratospheric research. These topics include ozone trends and climatology, ground based, aircraft, balloon, rocket and satellite measurements, Arctic and Antarctic research, global and regional modeling, and volcanic effects.

  3. A global tropospheric ozone climatology from trajectory-mapped ozone soundings

    NASA Astrophysics Data System (ADS)

    Liu, G.; Liu, J. J.; Tarasick, D. W.; Fioletov, V. E.; Jin, J. J.; Moeni, O.; Liu, X.; Sioris, C. E.

    2013-05-01

    A global three-dimensional (i.e. latitude, longitude, altitude) climatology of tropospheric ozone is derived from the ozone sounding record by trajectory mapping. Approximately 52 000 ozonesonde profiles from more than 100 stations worldwide since 1962 are used. The small number of stations causes the set of ozone soundings to be sparse in geographical spacing. Here, forward and backward trajectory calculations are performed for each sounding to map ozone measurements to a number of other locations, and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. This physically-based interpolation method offers obvious advantages over typical statistical interpolation methods. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Major regional features of the tropospheric ozone distribution are clearly evident in the global maps. An interpolation algorithm based on spherical functions is further used for smoothing and to fill in remaining data gaps. The resulting three-dimensional global tropospheric ozone climatology facilitates visualization and comparison of different years, decades, and seasons, and offers some intriguing insights into the global variation of tropospheric ozone. It will be useful for climate and air quality model initialization and validation, and as an a priori climatology for satellite data retrievals. Further division of the climatology into decadal averages provides a global view of tropospheric ozone trends, which appear to be surprisingly modest over the last four decades.

  4. Study of Tropospheric ozone (TOR) variability over Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pavan; Bortoli, Daniele; Salgado, Rui; Antón, Manuel; João Costa, Maria; Silva, Ana Maria

    2010-05-01

    To study tropospheric ozone (O3) variability and the increase in the number of months with higher tropospheric O3 concentration over the Iberian Peninsula, NASA Langley Tropospheric Ozone Residual (TOR) data has been analyzed for the 1979-2005 period. The maximum tropospheric O3 amount over the entire Iberian Peninsula was found in June (~41 DU) and a minimum in December (~29 DU). Over North Atlantic Coast (NAC) and Mediterranean Coast (MC) the maximum tropospheric O3 amount was found in July (~41 DU) and June (~42 DU) and the minimum was found in December (~28 DU and ~30 DU, respectively). The West Atlantic Coast (WAC), Pyrenees Mountain Range (PMR) and Central Iberian Peninsula (CIP) have an extended period of maximum tropospheric O3 amount, during June and July over WAC (~44 DU) and PMR (~39 DU), and during May, June and July over CIP (~40 DU). Similarly, WAC, PMR and CIP have an extended period of minimum tropospheric O3 amount, during December and January over WAC (~30 DU) and CIP (~29 DU) and November and December over PMR (~28 DU). The high concentration of ozone in July over the Atlantic Ocean near Iberian Peninsula are due to the presence of Azores anticyclone, extending in ridge through the Cantabrian Sea to the British Isles and West and Central Europe, and related photochemistry and dynamics, has profound effect on the observed higher ozone concentration over WAC zone. Strong seasonal cycle in tropospheric O3 amount has been observed with large variation over NAC (~49%), followed by WAC (~48%) and MC (~41%) compared to CIP and PMR (~38%). When the data are compared over the Iberian Peninsula for the two periods (1979-1993 and 1997-2005), a systematic increase in the number of months with higher tropospheric O3 concentration has been observed during the second period with respect to the first. These increases are almost 8% to 24% over NAC, 6% to 17% over WAC, 5% to 24% over CIP, 6% to 23% over MC and 13% to 18% over PMR. It has been observed that

  5. Accurate Satellite-Derived Estimates of Tropospheric Ozone Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Joiner, Joanna; Schoeberl, Mark R.; Vasilkov, Alexander P.; Oreopoulos, Lazaros; Platnick, Steven; Livesey, Nathaniel J.; Levelt, Pieternel F.

    2008-01-01

    Estimates of the radiative forcing due to anthropogenically-produced tropospheric O3 are derived primarily from models. Here, we use tropospheric ozone and cloud data from several instruments in the A-train constellation of satellites as well as information from the GEOS-5 Data Assimilation System to accurately estimate the instantaneous radiative forcing from tropospheric O3 for January and July 2005. We improve upon previous estimates of tropospheric ozone mixing ratios from a residual approach using the NASA Earth Observing System (EOS) Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) by incorporating cloud pressure information from OMI. Since we cannot distinguish between natural and anthropogenic sources with the satellite data, our estimates reflect the total forcing due to tropospheric O3. We focus specifically on the magnitude and spatial structure of the cloud effect on both the shortand long-wave radiative forcing. The estimates presented here can be used to validate present day O3 radiative forcing produced by models.

  6. OVERVIEW OF THE NORTH AMERICAN RESEARCH STRATEGY FOR TROPOSPHERIC OZONE

    EPA Science Inventory

    Tropospheric ozone (O3) and related products of photochemical smog, have been the subject of repeated control attempts for nearly 30 years in portions of North America. hese trace gases are known to be harmful to humans, animals, vegetation, and materials. s growth and industrial...

  7. Influence of Chlorine Emissions on Ozone Levels in the Troposphere

    EPA Science Inventory

    Chlorine emissions from cooling towers are emitted mainly as hypochlous acid, not as molecular chlorine. Chlorine emissions from cooling towers in electric utilities in the U.S. are estimated to be 4,400 tons per year. Molecular chlorine increases more tropospheric ozone than hyp...

  8. Spatial distribution of tropospheric ozone in western Washington, USA

    USGS Publications Warehouse

    Cooper, S.M.; Peterson, D.L.

    2000-01-01

    We quantified the distribution of tropospheric ozone in topographically complex western Washington state, USA (total area a??6000 km2), using passive ozone samplers along nine river drainages to measure ozone exposure from near sea level to high-elevation mountain sites. Weekly average ozone concentrations were higher with increasing distance from the urban core and at higher elevations, increasing a mean of 1.3 ppbv per 100 m elevation gain for all mountain transects. Weekly average ozone concentrations were generally highest in Cascade Mountains drainages east and southeast of Seattle (maximum=55a??67 pbv) and in the Columbia River Gorge east of Portland (maximum=59 ppbv), and lowest in the western Olympic Peninsula (maximum=34 ppbv). Higher ozone concentrations in the Cascade Mountains and Columbia River locations downwind of large cities indicate that significant quantities of ozone and ozone precursors are being transported eastward toward rural wildland areas by prevailing westerly winds. In addition, temporal (week to week) variation in ozone distribution is synchronous within and between all drainages sampled, which indicates that there is regional coherence in air pollution detectable with weekly averages. These data provide insight on large-scale spatial variation of ozone distribution in western Washington, and will help regulatory agencies optimize future monitoring networks and identify locations where human health and natural resources could be at risk.

  9. Spatial distribution of tropospheric ozone in western Washington, USA.

    PubMed

    Cooper, S M; Peterson, D L

    2000-03-01

    We quantified the distribution of tropospheric ozone in topographically complex western Washington state, USA (total area approximately 6000 km(2)), using passive ozone samplers along nine river drainages to measure ozone exposure from near sea level to high-elevation mountain sites. Weekly average ozone concentrations were higher with increasing distance from the urban core and at higher elevations, increasing a mean of 1.3 ppbv per 100 m elevation gain for all mountain transects. Weekly average ozone concentrations were generally highest in Cascade Mountains drainages east and southeast of Seattle (maximum=55-67 pbv) and in the Columbia River Gorge east of Portland (maximum=59 ppbv), and lowest in the western Olympic Peninsula (maximum=34 ppbv). Higher ozone concentrations in the Cascade Mountains and Columbia River locations downwind of large cities indicate that significant quantities of ozone and ozone precursors are being transported eastward toward rural wildland areas by prevailing westerly winds. In addition, temporal (week to week) variation in ozone distribution is synchronous within and between all drainages sampled, which indicates that there is regional coherence in air pollution detectable with weekly averages. These data provide insight on large-scale spatial variation of ozone distribution in western Washington, and will help regulatory agencies optimize future monitoring networks and identify locations where human health and natural resources could be at risk. PMID:15092980

  10. A global tropospheric ozone climatology from trajectory-mapped ozone soundings

    NASA Astrophysics Data System (ADS)

    Liu, G.; Liu, J.; Tarasick, D. W.; Fioletov, V. E.; Jin, J. J.; Moeini, O.; Liu, X.; Sioris, C. E.; Osman, M.

    2013-11-01

    A global three-dimensional (i.e. latitude, longitude, altitude) climatology of tropospheric ozone is derived from the ozone sounding record by trajectory mapping. Approximately 52 000 ozonesonde profiles from more than 100 stations worldwide since 1965 are used. The small number of stations results in a sparse geographical distribution. Here, forward and backward trajectory calculations are performed for each sounding to map ozone measurements to a number of other locations, and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. This physically based interpolation method offers obvious advantages over typical statistical interpolation methods. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Major regional features of the tropospheric ozone distribution are clearly evident in the global maps. An interpolation algorithm based on spherical functions is further used for smoothing and to fill in remaining data gaps. The resulting three-dimensional global tropospheric ozone climatology facilitates visualization and comparison of different years, decades, and seasons, and offers some intriguing insights into the global variation of tropospheric ozone. It will be useful for climate and air quality model initialization and validation, and as an a priori climatology for satellite data retrievals. Further division of the climatology into decadal and annual averages can provide a global view of tropospheric ozone changes, although uncertainties with regard to the performance of older sonde types, as well as more recent variations in operating procedures, need to be taken into account.

  11. Impact of Stratospheric Ozone Distribution on Features of Tropospheric Circulation

    NASA Astrophysics Data System (ADS)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2016-04-01

    In this work we study connections between stratospheric ozone distribution and general circulation patterns in the troposphere and aim to investigate the causal relationship between them, including the practical side of the influence of stratospheric ozone on tropospheric medium-range weather and regional climate. Analysis of several decades of observational data, which has been performed at the A.I. Voeikov Main Geophysical Observatory, suggests a clear relation between the stratospheric ozone distribution, upper stratospheric temperature field and planetary-scale air-masses boundaries in the troposphere [1]. Furthermore, it has been shown that each global air-mass, which can be attributed to the corresponding circulation cell in a conceptual model of tropospheric general circulation, has a distinct "regime" of ozone vertical distribution in the stratosphere [1-3]. Proceeding from atmospheric reanalyses combined with satellite and ground-based observations, we study time evolution of the upper-level frontal zones (stationary fronts) with the relevant jet streams, which can be treated as boundaries of global air-masses, in connection with the tropopause height and distribution of ozone in the stratosphere. For that, we develop an algorithm for automated identification of jet streams, stationary fronts and tropopause surface from gridded data (reanalyses or modelling results), and apply it for several cases associated with rapid changes in the stratospheric temperature and ozone fields, including SSW events over Eastern Siberia. Aiming to study the causal relationship between the features of tropospheric circulation and changes in the stratospheric ozone field, we estimate the time lag between these categories of processes on different time scales. Finally, we discuss the possibility to use the elementary circulation mechanisms classification (by B.L. Dzerdzeevski) in connection with analysis of the stratospheric ozone field and the relevant stratosphere-troposphere

  12. Application of a microprocessor controlled lidar to tropospheric ozone measurements

    NASA Technical Reports Server (NTRS)

    Stewart, R. W.; Bufton, J. L.; Matloff, G. L.

    1979-01-01

    A microprocessor controlled lidar system under construction at the NASA Goddard Space Flight Center is described and the problems in making space-based measurements of tropospheric ozone are considered. The differential absorption lidar using a dual wavelength, pulsed CO2 laser and direct detection receiver can significantly improve the existing global data base on tropospheric ozone burden. Sensitivity to tropospheric ozone can be obtained in the spaceborne version of lidar by selecting laser lines located in the wings of the target zone lines. Simulation studies using various laser line pairs in the P-branch of the CO2 9.4 micron band show that the ozone burden retrieval may be weighted to particular altitude regions. These simulation studies are based on numerical integration of differences in absorption coefficient at the two selected laser wavelengths using the AFGL absorption line parameter compilations, U.S. Standard Atmosphere ozone profile, and laser software. Simulation, data collection and reduction are performed by a microprocessor subsystem of the CO2 lidar.

  13. Influence of Stratospheric Ozone Distribution on Tropospheric Circulation Patterns

    NASA Astrophysics Data System (ADS)

    Barodka, Siarhei; Krasouski, Aliaksandr; Mitskevich, Yaroslav; Shalamyansky, Arkady

    2015-04-01

    In the present study we investigate the cause-and-effect relationship between the stratospheric ozone distribution and tropospheric circulation, focusing our attention mainly on the possible "top-down" side of this interaction: the impact of the stratosphere on tropospheric circulation patterns and the associated weather and climate conditions. Proceeding from analysis of several decades of observational data performed at the A.I. Voeikov Main Geophysical Observatory, which suggests a clear relation between the stratospheric ozone distribution, temperature field of the lower stratosphere and air-masses boundaries in the upper troposphere, we combine atmospheric reanalyzes and ground-based observations with numerical simulations to identify features of the general circulation that can be traced back to anomalies in the stratospheric ozone field. Specifically, we analyze the time evolution of instantaneous position of the stationary upper-level atmospheric fronts, defining the boundaries of global tropospheric air masses associated with basic cells of general circulation. We assume that stratospheric heating in ozone-related processes can exert its influence on the location of stationary fronts and characteristics of general circulation cells by displacing the tropopause, which itself is defined by a dynamical equilibrium between tropospheric vertical convection and stratospheric radiative heating. As an example, we consider the Spring season of 2013. Unusually high total ozone column (TOC) values observed in Northern Hemisphere (NH) at the beginning of 2013 induced low tropopause level in the Atlantic region and southward displacement of the polar front, leading to an anomalously cold Spring in Europe. Furthermore, we study manifestations of this mechanism in the aftermath of sudden stratospheric warming (SSW) events. In particular, the November 2013 SSW over Eastern Siberia, which is characterized by abrupt stratospheric temperatures change in the course of one day

  14. An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John

    2015-04-01

    Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.

  15. Tropospheric Bromine Chemistry: Implications for Present and Pre-industrial Ozone and Mercury

    NASA Technical Reports Server (NTRS)

    Parella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; VanRoozendael, M.

    2012-01-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1-8 nmol/mol (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4 %. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  16. Multi-model prediction of climate-induced changes in ozone and reactive nitrogen fluxes into the troposphere

    NASA Astrophysics Data System (ADS)

    Hegglin, M. I.; Shepherd, T. G.; Ccmval Modelling Team

    2010-12-01

    Chemistry-Climate Models (CCMs) consistently predict a strengthening of the stratospheric Brewer-Dobson circulation due to climate change. The associated changes in the distribution of stratospheric ozone and reactive nitrogen will affect not only the flux of those tracers into the troposphere, but also the amount of ultra-violet radiation reaching the troposphere. While the contribution of stratospheric ozone to the total tropospheric ozone budget is only about 10%, it strongly affects ozone concentrations in the upper troposphere, where ozone has a relatively long lifetime (about one month) and its largest impact on radiative forcing. At the same time, changes in reactive nitrogen and UV radiation may influence the efficacy of chemical processes in the troposphere, and have adverse effects on human beings and the ecosystem. We present new results from a multi-model comparison of predicted changes in stratospheric ozone and reactive nitrogen fluxes using state-of-the-art CCMs, and the role of ozone depletion and recovery in modulating them. In order to gain confidence in the model predictions, we also evaluate the models’ capabilities to represent dynamical and chemical processes in the lower stratosphere through process-oriented diagnostics using both aircraft and satellite data.

  17. Is the residual vertical velocity a good proxy for stratosphere-troposphere exchange of ozone?

    NASA Astrophysics Data System (ADS)

    Hsu, Juno; Prather, Michael J.

    2014-12-01

    Stratosphere-troposphere exchange (STE) of ozone (O3) is key in the budget of tropospheric O3, in turn affecting climate forcing and global air quality. We compare three commonly used diagnostics meant to quantify cross-tropopause O3 fluxes with a Chemistry-Transport Model driven by two distinct European Centre forecast fields. Our reference case calculates accurate, geographically resolved net transport across an isosurface in artificial tracer e90 representing the tropopause. Hemispheric fluxes derived from the ozone mass budget of the lowermost stratosphere yield similar results. Use of the Brewer-Dobson residual vertical velocity as a scaled proxy for ozone flux, however, fails to capture the interannual variability. Thus, the common notion that the strength of stratospheric overturning circulation is a good measure for global STE does not apply to O3. Climatic variability in the modeled O3 flux needs to be diagnosed directly rather than indirectly through the overturning circulation.

  18. Tropospheric ozone and ozone profiles retrieved from GOME-2 and their validation

    NASA Astrophysics Data System (ADS)

    Miles, G. M.; Siddans, R.; Kerridge, B. J.; Latter, B. G.; Richards, N. A. D.

    2015-01-01

    This paper describes and assesses the performance of the RAL (Rutherford Appleton Laboratory) ozone profile retrieval scheme for the Global Ozone Monitoring Experiment 2 (GOME-2) with a focus on tropospheric ozone. Developments to the scheme since its application to GOME-1 measurements are outlined. These include the approaches developed to account sufficiently for UV radiometric degradation in the Hartley band and for inadequacies in knowledge of instrumental parameters in the Huggins bands to achieve the high-precision spectral fit required to extract information on tropospheric ozone. The assessment includes a validation against ozonesondes (sondes) sampled worldwide over 2 years (2007-2008). Standard deviations of the ensemble with respect to the sondes are considerably lower for the retrieved profiles than for the a priori, with the exception of the lowest subcolumn. Once retrieval vertical smoothing (averaging kernels) has been applied to the sonde profiles there is a retrieval bias of 6% (1.5 DU) in the lower troposphere, with smaller biases in the subcolumns above. The bias in the troposphere varies with latitude. The retrieval underestimates lower tropospheric ozone in the Southern Hemisphere (SH) (15-20% or ~ 1-3 DU) and overestimates it in the Northern Hemisphere (NH) (10% or 2 DU). The ability of the retrieval to reflect the geographical distribution of lower tropospheric ozone, globally (rather than just ozonesonde launch sites) is demonstrated by comparison with the chemistry transport model TOMCAT. For a monthly mean of cloud-cleared GOME-2 pixels, a correlation of 0.66 is found between the retrieval and TOMCAT sampled accordingly, with a bias of 0.7 Dobson Units. GOME-2 estimates higher concentrations in NH pollution centres but lower ozone in the Southern Ocean and South Pacific, which is consistent with the comparison to ozonesondes.

  19. Developing a predictive tropospheric ozone model for Tabriz

    NASA Astrophysics Data System (ADS)

    Khatibi, Rahman; Naghipour, Leila; Ghorbani, Mohammad A.; Smith, Michael S.; Karimi, Vahid; Farhoudi, Reza; Delafrouz, Hadi; Arvanaghi, Hadi

    2013-04-01

    Predictive ozone models are becoming indispensable tools by providing a capability for pollution alerts to serve people who are vulnerable to the risks. We have developed a tropospheric ozone prediction capability for Tabriz, Iran, by using the following five modeling strategies: three regression-type methods: Multiple Linear Regression (MLR), Artificial Neural Networks (ANNs), and Gene Expression Programming (GEP); and two auto-regression-type models: Nonlinear Local Prediction (NLP) to implement chaos theory and Auto-Regressive Integrated Moving Average (ARIMA) models. The regression-type modeling strategies explain the data in terms of: temperature, solar radiation, dew point temperature, and wind speed, by regressing present ozone values to their past values. The ozone time series are available at various time intervals, including hourly intervals, from August 2010 to March 2011. The results for MLR, ANN and GEP models are not overly good but those produced by NLP and ARIMA are promising for the establishing a forecasting capability.

  20. Effects of stratospheric ozone recovery on tropospheric chemistry and air quality

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wu, S.; Wang, Y.

    2013-08-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increases by 0.78%. The perturbations to tropospheirc ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 5% for some regions.

  1. Impacts of Stratospheric Ozone Change on Tropospheric Chemistry and Air Quality

    NASA Astrophysics Data System (ADS)

    Wu, S.; Zhang, H.

    2013-05-01

    The stratospheric ozone has decreased greatly since 1980 due to ozone depleting substances (ODSs). As a result of the implementation of the Montreal Protocol and its Amendments and Adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. We examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. Increases in ozone lifetime by up to 7% are calculated in the troposphere. The global average OH decreases by 1.74% and the global burden of tropospheric ozone increased by 0.78%. The perturbations to tropospheirc ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 5% for some regions.

  2. Ozone Production In The Upper Troposphere

    NASA Astrophysics Data System (ADS)

    Phillips, G. J.; Actoleicester Team

    A box modelling study has been carried out using data obtained from the UK -NERC funded UTLS-OZONE and EXPORT measurement campaigns. Data from the campaigns was used to constrain the model and the subsequent results were used to calculate ozone tendencies within air mass types encountered. Both average and air mass specific analyses were carried out. These campaigns were conducted during the spring and summer of 2000 respectively, onboard the UKMO C-130 Hercules aircraft. The spring data was taken mainly from the north Atlantic, west of Scotland, and the summer data was collected over central Europe. Five-day back trajectories calculated from ECMWF wind fields by the Universities of Reading and Cambridge were used to separate the data for analysis.

  3. Distribution of total ozone and stratospheric ozone in the tropics - Implications for the distribution of tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Fishman, Jack; Larsen, Jack C.

    1987-01-01

    Climatologies of total columnar ozone and integrated stratospheric ozone amounts at low latitudes (15 deg N to 15 deg S), derived from satellite observations, are presented. A significant longitudinal variability in total ozone is present, with highest values generally located between 60 deg W and 60 deg E. The integrated stratospheric component of total ozone, on the other hand, does not exhibit a longitudinal preference for high values. Therefore it is hypothesized that the climatological longitudinal distribution of total ozone reflects the variability of the abundance of tropospheric ozone at low latitudes. Furthermore, it is speculated that in situ photochemical production of ozone resulting from biomass burning may be responsible for the observed enhancement of total ozone at these longitudes.

  4. Sensitivity of Assimilated Tropical Tropospheric Ozone to the Meteorological Analyses

    NASA Technical Reports Server (NTRS)

    Hayashi, Hiroo; Stajner, Ivanka; Pawson, Steven; Thompson, Anne M.

    2002-01-01

    Tropical tropospheric ozone fields from two different experiments performed with an off-line ozone assimilation system developed in NASA's Data Assimilation Office (DAO) are examined. Assimilated ozone fields from the two experiments are compared with the collocated ozone profiles from the Southern Hemispheric Additional Ozonesondes (SHADOZ) network. Results are presented for 1998. The ozone assimilation system includes a chemistry-transport model, which uses analyzed winds from the Goddard Earth Observing System (GEOS) Data Assimilation System (DAS). The two experiments use wind fields from different versions of GEOS DAS: an operational version of the GEOS-2 system and a prototype of the GEOS-4 system. While both versions of the DAS utilize the Physical-space Statistical Analysis System and use comparable observations, they use entirely different general circulation models and data insertion techniques. The shape of the annual-mean vertical profile of the assimilated ozone fields is sensitive to the meteorological analyses, with the GEOS-4-based ozone being closest to the observations. This indicates that the resolved transport in GEOS-4 is more realistic than in GEOS-2. Remaining uncertainties include quantification of the representation of sub-grid-scale processes in the transport calculations, which plays an important role in the locations and seasons where convection dominates the transport.

  5. Creating a Satellite-Based Record of Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Oetjen, Hilke; Payne, Vivienne H.; Kulawik, Susan S.; Eldering, Annmarie; Worden, John; Edwards, David P.; Francis, Gene L.; Worden, Helen M.

    2013-01-01

    The TES retrieval algorithm has been applied to IASI radiances. We compare the retrieved ozone profiles with ozone sonde profiles for mid-latitudes for the year 2008. We find a positive bias in the IASI ozone profiles in the UTLS region of up to 22 %. The spatial coverage of the IASI instrument allows sampling of effectively the same air mass with several IASI scenes simultaneously. Comparisons of the root-mean-square of an ensemble of IASI profiles to theoretical errors indicate that the measurement noise and the interference of temperature and water vapour on the retrieval together mostly explain the empirically derived random errors. The total degrees of freedom for signal of the retrieval for ozone are 3.1 +/- 0.2 and the tropospheric degrees of freedom are 1.0 +/- 0.2 for the described cases. IASI ozone profiles agree within the error bars with coincident ozone profiles derived from a TES stare sequence for the ozone sonde station at Bratt's Lake (50.2 deg N, 104.7 deg W).

  6. Urban greening impacts on tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Grote, R.; Churkina, G.; Butler, T. M.; Morfopoulos, C.

    2013-12-01

    Cities are characterized by elevated air temperatures as well as high anthropogenic emissions of air pollutants. Cities' greening in form of urban parks, street trees, and vegetation on roofs and walls of buildings is supposed to generally mitigate negative impacts on human health and well-being. However, high emissions of biogenic volatile organic compounds (BVOC) from certain popular urban plants in combination with the elevated concentrations of NOx have the potential to increase ground-level ozone concentrations - with negative impacts on health, agriculture, and climate. Policies targeting reduction of ground-level ozone in urban and suburban areas therefore must consider limiting BVOC emissions along with measures for decreasing NOx and VOC from anthropogenic sources. For this, integrated climate/ chemistry models are needed that take into account the species-specific physiological responses of urban plants which in turn drive their emission behavior. Current models of urban climate and air quality 1) do not account for the feedback between ozone concentrations, productivity, and BVOC emission and 2) do not distinguish different physiological properties of urban tree species. Instead environmental factors such as light, temperature, carbon dioxide, and water supply are applied disregarding interactions between such influences. Thus we may not yet be able to represent the impacts of air pollution under multiple changed conditions such as climate change, altered anthropogenic emission patterns, and new urban structures. We present here the implementation of the new BVOC emission model (Morfopolous et al., in press) that derives BVOC emissions directly from the electron production potential and consumption from photosynthesis calculation that is already supplied by the CLM land surface model. The new approach has the advantage that many environmental drivers of BVOC emissions are implicitly considered in the description of plant photosynthesis and phenology. We

  7. Seasonal Variability in Tropospheric Ozone Distribution Over Qatar

    NASA Astrophysics Data System (ADS)

    Ayoub, Mohammed; Ackermann, Luis

    2015-04-01

    We report on the vertical distribution and seasonal variability in tropospheric ozone over the Middle East through one year of weekly ozonesondes launched from Doha, Qatar during 2014. A total of 49 2Z-V7 DMT/EN-SCI Electrochemical Concentration Cell (ECC) ozonesondes employing a 1% buffered potassium iodide solution (KI), coupled with iMet-1-RS GPS radiosondes were launched around 1300 local time. The authors used the SkySonde telemetry software (developed by CIRES and NOAA/ESRL) and developed robust in-house data quality assurance and validation methodologies. The average height of the thermal tropopause is between 15-17.5 km (125-85 hPa). Monthly average relative humidity around the tropopause shows an enhancement during the months of June through the beginning of October. Monthly average temperature profiles show the development of the subtropical subsidence inversion around 5-6 km (450-520 hPa) between the months of April through October. The subsidence inversion is strongest during the months of June and July and is accompanied by a sharp drop in relative humidity over a 100-300 m in the vertical. The monthly average ozone background concentration between the Planetary Boundary Layer (PBL) height and the subsidence inversion increases from 50 ppb in the winter to almost 80 ppb in the summer months. An enhancement of up to 50% in the average ozone in the mid-to-upper troposphere (above the subsidence inversion) is strongest during the summer months (June through September) and results in average concentrations between 80-100 ppb. In the upper troposphere (above 13 km/200 hPa) ozone concentrations are highest during the spring and summer months. This is coupled with a drop in the average height of the tropopause. HYSPLIT back-trajectory analysis shows the enhancement in mid-to-upper tropospheric ozone in the summer is due to persistent high pressure over the Middle East between the months of June through September. Evidence of Stratosphere-Troposphere Exchange

  8. Surface and Tropospheric Ozone Profile Variability (1999-2014) at the TOLNet Site of Table Mountain, California

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, M. J.; Leblanc, T.

    2015-12-01

    Ozone in the lower troposphere acts as an air pollutant affecting human health and vegetation. Tropospheric ozone sources and variability are not yet fully identified or understood and recent studies reveal the importance of increasing the number of tropospheric ozone profiling stations and long term measurements. As part of the international monitoring network NDACC, and the U.S.-based network TOLNet, a differential absorption lidar has been performing tropospheric ozone measurements (3-20 km) at the JPL Table Mountain Facility (TMF, California) since 1999, and surface measurements have been performed since 2013 with a UV photometric analyzer. Because of the site's geolocation and high elevation, background tropospheric ozone, unaffected by the boundary layer dynamics and local anthropogenic emissions of ozone precursors, is usually expected. However, transboundary ozone contributions such as stratospheric intrusions and Asian pollution episodes are frequently detected. In this study, a statistical analysis of the 14-year lidar profiles and the 2.5-year surface data is presented. Seasonal, interannual and diurnal variability and its possible causes (e.g. El Nino/La Nina events, North American Monsoon) are investigated. Together with the high elevation surface data gathered at TMF, surface data from ARB stations nearby are analyzed to understand the lowermost tropospheric ozone variability component. The frequency of stratospheric intrusions and Asian pollution episodes reaching the Western U.S. is also examined in an attempt to understand the relative contribution of each process to the observed variability throughout the troposphere. The Table Mountain surface and lidar measurements are expected to contribute significantly to the emerging system of global air quality observations, and to the improvement of global and regional data assimilation and modeling.

  9. Role of ozone precursors in tropospheric ozone formation and control: A report to Congress

    SciTech Connect

    Not Available

    1993-07-01

    Tropospheric ozone pollution, which occurs at ground level and is the major component of ground-level summertime smog, remains an important environmental and health concern despite nearly 20 years of regulatory efforts. Ozone is a secondary pollutant formed in the atmosphere by reactions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) in the presence of sunlight. Carbon monoxide (CO) also plays a role in the formation of ozone. Major sources of VOCs include exhaust and evaporative emissions from motor vehicles, emissions from solvent use and emissions from the chemical and petroleum industries. The following EPA perspectives identify two key components (strategy selection; modeling and data bases) which must be addressed in resolving the tropospheric ozone problem.

  10. Factors controlling global tropospheric ozone: roles of isoprene chemistry, tropospheric halogen chemistry, convection, and lightning NOx sources

    NASA Astrophysics Data System (ADS)

    Hu, L.; Jacob, D. J.; Zhang, Y.; Liu, X.; Zhang, L.

    2015-12-01

    Ozone is central to our understanding of tropospheric oxidant chemistry through its driving of radical cycles. Yet our understanding of factors determining its spatial distribution and long-term trend is still poor. In this work, we use the GEOS-Chem chemical transport model as a platform to test our current knowledge of key factors controlling tropospheric ozone. We evaluate the most recent GEOS-Chem simulation against in-situ data using ozonesonde networks from WOUDC and NOAA-GMD and using aircraft observations from MOZAIC/IAGOS, to examine the vertical distribution of modeled tropospheric ozone. Satellite observed ozone data from OMI (Ozone Monitoring Instrument) are used to assess the spatial distribution of the predicted ozone concentrations. We also examine different versions of GEOS-Chem outputs from historical benchmarks and from sensitivity runs (such as changing in chemistry and meteorological fields) for their capabilities to reproduce observed tropospheric ozone patterns. In this presentation, we interpret these analyses in terms of present understanding in isoprene chemistry, tropospheric bromine chemistry, lightning NOx sources and deep convection, and examine their implications for key model processes controlling the abundance and variability of global tropospheric ozone.

  11. Tropospheric ozone production regions and the intercontinental origins of surface ozone over Europe

    NASA Astrophysics Data System (ADS)

    Derwent, Richard G.; Utembe, Steven R.; Jenkin, Michael E.; Shallcross, Dudley E.

    2015-07-01

    Ozone tagged labelling schemes have been implemented in a global Lagrangian chemistry-transport model to identify the intercontinental origins of surface ozone in Europe. Stratosphere-troposphere exchange gave rise to between 3 and 5 ppb across Europe, whereas the mid-latitudes of the Middle East, Asia and the Pacific Ocean region contributed 6-8 ppb. Surface ozone levels of 10-16 ppb were associated with the mid-latitudes of North America and the North Atlantic Ocean regions. Appreciable intercontinental ozone production occurred downwind of continental regions and above the surface layer. Intercontinental ozone formation and transport from tropical regions contributed about 4 ppb and was much less efficient compared with that from mid-latitudes. There were approaching 60 chemical processes driving intercontinental ozone formation, of which the HO2 + NO, CH3O2 + NO and CH3COO2 + NO reactions were the most important. Ozone production appeared to be driven by OH oxidation of secondary reaction products rather than the oxidation of primary emitted VOCs. The largest intercontinental ozone contributions amounted to about 20 ppb from North America to European baseline stations, 14 ppb from Asia to North American baseline stations and 10 ppb from Asia to European baseline stations. It is possible that changing intercontinental ozone production and transport could have led to seasonal ozone trends and shifts in seasonal cycles at northern hemisphere mid-latitude baseline ozone monitoring stations.

  12. Direct measurements of tropospheric ozone from TOMS data

    NASA Technical Reports Server (NTRS)

    Hudson, Robert D.

    1993-01-01

    In the past year, we have made measurements of the tropospheric total column of ozone during the biomass burning season in Africa (August to October). Fishman et. al. had reported previously that by taking a time average of the low spatial resolution data from TOMS (Total Ozone Mapping Spectrometer) on Nimbus-7 (referred to as the Grid-T data set), during the biomass burning season in Africa, a plume of ozone extends from the East coast of Africa into the Atlantic. In this report, we present an analysis that we have made using the measured TOMS radiances taken from the High Density TOMS data set (referred as the HDT data set), which examines this plume in more detail.

  13. Effects of 1997-1998 El Nino on Tropospheric Ozone and Water Vapor

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Min, W.; Read, W. G.

    1998-01-01

    This paper analyzes the impact of the 1997-1998 El Nino on tropospheric column ozone and tropospheric water vapor derived respectively from the Total Ozone Mapping Spectrometer (TOMS) on Earth Probe and the Microwave Limb Scanning instrument on the Upper Atmosphere Research Satellite. The 1997-1998 El Nino, characterized by an anomalous increase in sea-surface temperature (SST) across the eastern and central tropical Pacific Ocean, is one of the strongest El Nino Southern Oscillation (ENSO) events of the century, comparable in magnitude to the 1982-1983 episode. The major impact of the SST change has been the shift in the convection pattern from the western to the eastern Pacific affecting the response of rain-producing cumulonimbus. As a result, there has been a significant increase in rainfall over the eastern Pacific and a decrease over the western Pacific and Indonesia. The dryness in the Indonesian region has contributed to large-scale burning by uncontrolled wildfires in the tropical rainforests of Sumatra and Borneo. Our study shows that tropospheric column ozone decreased by 4-8 Dobson units (DU) in the eastern Pacific and increased by about 10-20 DU in the western Pacific largely as a result of the eastward shift of the tropical convective activity as inferred from National Oceanic and Atmospheric Administration (NOAA) outgoing longwave radiation (OLR) data. The effect of this shift is also evident in the upper tropospheric water vapor mixing ratio which varies inversely as ozone (O3). These conclusions are qualitatively consistent with the changes in atmospheric circulation derived from zonal and vertical wind data obtained from the Goddard Earth Observing System data assimilation analyses. The changes in tropospheric column O3 during the course of the 1997-1998 El Nino appear to be caused by a combination of large-scale circulation processes associated with the shift in the tropical convection pattern and surface/boundary layer processes associated with

  14. Data Assimilation at High Spatial Resolution in a Study of Tropospheric ozone and Stratosphere-Troposphere Exchange

    NASA Astrophysics Data System (ADS)

    Wargan, K.; Pawson, S.

    2011-12-01

    Assimilation of retrieved statellite ozone data is a statisticaly optimal way to combine high-quality observations with transport model output. It has been shown that assimilated ozone fields can exhibit a good agreement with independent data including satellite, ground-based and sonde measurements. Assimilation at high vertical and horizontal resolutions provides a unique opportunity to map and study the occurence and evolution of finer scale features of a tracer field on a global scale. This paper presents results of a long assimilation constrained by the ozone data from two EOS Aura sensors: the total column ozone from the Ozone Monitoring Instrument (OMI) and high vertical resolution stratospheric profiles from Microwave Limb Sounder (MLS, version 3.3). The experiment uses GMAO's GEOS-5 data assimilation system run at a 0.5 degree horizontal resolution on 72 terrain-following levels. Our focus is on the the upper troposphere - lower stratosphere (UTLS) layer and tropospheric ozone column. The UTLS is especially important for correct representation of radiative forcing in forecast models with interactive ozone such as GEOS-5, as well as for scientific understanding of the tropospheric ozone budget. The UTLS results are interpreted using different definitions of the tropopause in order to identify stratosphere-troposphere exchange events. For the tropospheric column, the advantages of combining high horizontal resolution of the model with the small footprint of the OMI instruments are highlighted.

  15. Springtime variability of lower tropospheric ozone over Eastern Asia: contributions of cyclonic activity and pollution as observed from space with IASI

    NASA Astrophysics Data System (ADS)

    Dufour, G.; Eremenko, M.; Cuesta, J.; Doche, C.; Foret, G.; Beekmann, M.; Cheiney, A.; Wang, Y.; Cai, Z.; Liu, Y.; Takigawa, M.; Kanaya, Y.; Flaud, J.-M.

    2015-03-01

    We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variability of lower tropospheric ozone at the scale of Eastern Asia. Lower tropospheric partial columns from surface to 6 km are retrieved from IASI with a maximum of sensitivity between 3 and 4 km. We focus our analysis on the month of May 2008 for which tropospheric ozone presents typically amongst the largest concentrations along the year. We combine IASI observations with meteorological reanalyses from ERA-Interim in order to investigate the processes that control the spatial and temporal distribution of lower tropospheric ozone, especially in case of ozone enhancement. The succession of low- and high-pressure systems drives the day-to-day variability of lower tropospheric ozone over North East Asia. The analysis of two episodes with ozone enhancement at the synoptic scale of East Asia shows that the reversible subsiding and ascending ozone transfers in the UTLS region occurring in the vicinity of low-pressure systems and related to tropopause height affect the upper and lower tropospheric ozone over large regions, especially north to 40° N and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible downward transport of ozone-rich air masses from the UTLS to the lower troposphere occurs more locally. Its contribution to the lower tropospheric ozone column is difficult to dissociate from the tropopause perturbations induced by the weather systems. For regions south to 40° N, a significant correlation between lower tropospheric ozone and carbon monoxide (CO) observations from IASI has been found, especially over North China Plain (NCP). Considering carbon monoxide observations as pollutant tracer, the O3-CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such large polluted regions significantly contributes to the ozone

  16. Effects of the 2004 El Nino on Tropospheric Ozone and Water Vapor

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Schoeberl, M. R.; Froidevaux, L.; Read, W. G.; Levelt, P. F.; Bhartia, P. K.

    2007-01-01

    The global effects of the 2004 El Nino on tropospheric ozone and H2O based on Aura OM1 and MLS measurements are analyzed. Although it was a weak El Nino from a historical perspective, it produced significant changes in these parameters in tropical latitudes. Tropospheric ozone increased by 10-20% over most of the western Pacific region and decreased by about the same amount over the eastern Pacific region. H2O in the upper troposphere showed similar changes but with opposite sign. These zonal changes in tropospheric ozone and H2O are caused by the eastward shift in the Walker circulation in the tropical pacific region during El Nino. For the 2004 El Nino, biomass burning did not have a significant effect on the ozone budget in the troposphere unlike the 1997 El Nino. Zonally averaged tropospheric column ozone did not change significantly either globally or over the tropical and subtropical latitudes.

  17. Estimating the Tropospheric Ozone Distribution by the Assimilation of Satellite Data

    NASA Technical Reports Server (NTRS)

    Hayashi, Hiroo; Stajner, Ivanka; Winslow, Nathan; Jones, Dylan B. A.; Pawson, Steven; Thompson, Anne M.

    2003-01-01

    Tropospheric ozone is important to the environment, because it acts as a strong oxidant to control the concentrations of many reduced gases (methane, carbon monoxide, ... ), its radiative forcing plays a significant role in the greenhouse effect, and direct contact with ozone is harmful to human health. Tropospheric ozone, whose main sources are intrusion from the stratosphere and chemical production from source gases associated with urban pollution or biomass burning, varies on a wide range of spatial and temporal scales. Its transport and chemistry can be influenced by weather, seasonal, or multiannual variability. Despite the importance of tropospheric ozone, it contributes only about 10% of the total ozone loading in the atmosphere. Consequently, satellite instruments lose sensitivity below the stratospheric ozone peak, and provide little information about middle and lower tropospheric ozone. This talk will discuss recent modifications made to the satellite ozone data assimilation system at NASA's Data Assimilation Office (DAO) in order to provide better tropospheric ozone columns and profiles. We use a version of the system that assimilates only the data from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument. The quality of the assimilated ozone in the tropical troposphere is evaluated by comparison with independent observations obtained from the Southern Hemispheric Additional Ozonesondes (SHADOZ) network. It is shown that the quality of ozone fields is sensitive to the winds used in the transport model. Increasing the vertical resolution of the model also has a beneficial impact. The assimilated ozone in the lower troposphere was substantially improved by inclusion of tropospheric ozone production, loss, and dry deposition rates from the Harvard GEOS-CHEM model. The mechanisms behind these results will be examined and the implications for our understanding of tropospheric ozone will be discussed.

  18. Impact of Large-Scale Boreal Fires on Levels of Tropospheric Ozone in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Lapina, K.; Honrath, R.; Owen, C.; Val Martin, M.; Strane, J.

    2005-12-01

    We present an analysis of ozone and carbon monoxide measurements in the central N. Atlantic lower free troposphere that is designed to determine the impact of boreal wildfire emissions on ozone levels in distant downwind regions. Measurements were made at the PICO-NARE mountaintop station (2225 m asl) in the Azores Islands. The station is frequently impacted by outflow from high-latitude regions where fires are common in the summer. Here, we use summer observations of ozone and carbon monoxide made in 2001, 2003, and 2004, to assess the impact of boreal forest fires on the distribution of ozone mixing ratios at this location. Using HYSPLIT backward trajectories, we selected time periods during which transport from boreal regions occurred. These periods were then further segregated into two subsets: periods with and periods without significant upwind fire emissions, using enhanced CO as an indicator of fire-affected flow. Through comparison of the resulting ozone distributions, we deduce that emissions from boreal fires led to significant ozone production. It is likely that this production was partly or largely responsible for significant shifts in the ozone distribution toward higher mixing ratios during 2003 (due to Siberian fires) and 2004 (due to Alaskan and Canadian fires). Global circulation model (GCM) simulations predict increased boreal fire danger resulting from global climate change in future decades. Our analyses imply that increased boreal fire magnitudes would enhance the summertime ozone background over large regions of Northern Hemisphere, providing a climate feedback (as ozone is a greenhouse gas) and negatively affecting the ability of downwind nations to meet ozone air quality standards.

  19. Development of a portable instrument to measure ozone production rates in the troposphere

    NASA Astrophysics Data System (ADS)

    Sklaveniti, Sofia; Locoge, Nadine; Stevens, Philip; Kumar, Vinod; Sinha, Vinayak; Dusanter, Sébastien

    2015-04-01

    Ground-level ozone is a key species related to air pollution, causing respiratory problems, damaging crops and forests, and affecting the climate. Our current understanding of the tropospheric ozone-forming chemistry indicates that net ozone production occurs via reactions of peroxy radicals (HO2 + RO2) with NO producing NO2, whose photolysis leads to O3 formation. Production rates of tropospheric ozone, P(O3), depend on concentrations of oxides of nitrogen (NOx = NO + NO2) and Volatile Organic Compounds (V OCs), but also on production rates of ROx radicals (OH + HO2 + RO2). The formation of ozone follows a complex nonlinear chemistry that makes strategies for reducing ozone difficult to implement. In this context, atmospheric chemistry models are used to develop emission regulations, but there are still uncertainties associated with the chemical mechanisms used in these models. Testing the ozone formation chemistry in atmospheric models is needed, in order to ensure the development of effective strategies for ozone reduction. We will present the development of an instrument for direct measurements of ozone production rates (OPR) in ambient air. The OPR instrument is made of three components: (i) two quartz flow tubes to sample ambient air, one exposed to solar radiation and one covered by a UV filter, (ii) a NO2-to-O3 conversion unit, and (iii) an ozone analyzer. The total amount of ozone exiting each flow tube is conserved in the form of Ox = NO2 + O3. Ozone production rates P(O3) are derived from the difference in Ox concentration between the two flow tubes, divided by the exposure time of air inside the flow tubes. We will present studies that were carried out in the laboratory to characterize each part of the instrument and we will discuss the performances of the OPR instrument based on experiments carried out using synthetic air mixtures of known composition (NOx and V OCs). Chemical modeling will also be presented to assess the reliability of ozone

  20. Long-term observations of tropospheric ozone: GAW Measurement Guidelines

    NASA Astrophysics Data System (ADS)

    Tarasova, Oksana; Galbally, Ian E.; Schultz, Martin G.

    2013-04-01

    The Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) coordinates long-term observations of the chemical composition and physical properties of the atmosphere which are relevant for understanding of atmospheric chemistry and climate change. Atmospheric observations of reactive gases (tropospheric ozone, carbon monoxide, volatile organic compounds and nitrogen oxides) coordinated by the GAW Programme complement local and regional scale air quality monitoring efforts. As part of the GAW quality assurance (QA) system detailed measurement guidelines for atmospheric trace species are developed by international expert teams at irregular intervals. The most recent report focuses on continuous in-situ measurements of ozone in the troposphere, performed in particular at continental or island sites with altitudes ranging from sea level to mountain tops. Data Quality Objectives (DQOs) are defined for different applications of the data (e.g. trend analysis and verification of global model forecasts). These DQOs include a thorough discussion of the tolerable level of measurement uncertainty and data completeness. The guidelines present the best practices and practical arrangements adopted by the GAW Programme in order to enable the GAW station network to approach or achieve the defined tropospheric ozone DQOs. The document includes information on the selection of station and measurement locations, required skills and training of staff, recommendations on the measurement technique and the necessary equipment to perform highest quality measurements, rules for conducting the measurements, preparing the data and archiving them, and more. Much emphasis is given to discussions about how to ensure the quality of the data through tracing calibrations back to primary standards, proper calibration and data analysis, etc. In the GAW Programme the QA system is implemented through Central Facilities (Central Calibration Laboratories, World and Regional

  1. On the transfer of stratospheric ozone into the troposphere near the North Pole

    NASA Technical Reports Server (NTRS)

    Oltmans, Samuel J.; Raatz, Wolfgang E.; Komhyr, Walter D.

    1989-01-01

    A series of nearly daily ozone vertical profiles obtained at station T-3 on Fletcher's Ice Island (about 85 deg N, about 90 deg W) during the period January-March 1971 shows several significant ozone intrusions into the troposphere. These intrusions are not only associated with enhanced ozone amounts in the stratosphere but also require tropopause folding events to transport ozone into the troposphere. These folds in the arctic tropopause appear to be capable of contributing significantly to the ozone budget of the arctic troposphere during the late winter and spring seasons. The importance of tropopause folding for bringing ozone into the troposphere seen in the daily ozone profiles confirms the results found in the Arctic Gas and Aerosol Sampling Program aircraft flights.

  2. Seasonal and Interannual Variabilities in Tropical Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.

    1999-01-01

    This paper presents a detailed characterization of seasonal and interannual variability in tropical tropospheric column ozone (TCO). TCO time series are derived from 20 years (1979-1998) of total ozone mapping spectrometer (TOMS) data using the convective cloud differential (CCD) method. Our study identifies three regions in the tropics with distinctly different zonal characteristics related to seasonal and interannual variability. These three regions are the eastern Pacific, Atlantic, and western Pacific. Results show that in both the eastern and western Pacific seasonal-cycle variability of northern hemisphere (NH) TCO exhibits maximum amount during NH spring whereas largest amount in southern hemisphere (SH) TCO occurs during SH spring. In the Atlantic, maximum TCO in both hemispheres occurs in SH spring. These seasonal cycles are shown to be comparable to seasonal cycles present in ground-based ozonesonde measurements. Interannual variability in the Atlantic region indicates a quasi-biennial oscillation (QBO) signal that is out of phase with the QBO present in stratospheric column ozone (SCO). This is consistent with high pollution and high concentrations of mid-to-upper tropospheric O3-producing precursors in this region. The out of phase relation suggests a UV modulation of tropospheric photochemistry caused by the QBO in stratospheric O3. During El Nino events there is anomalously low TCO in the eastern Pacific and high values in the western Pacific, indicating the effects of convectively-driven transport of low-value boundary layer O3 (reducing TCO) and O3 precursors including H2O and OH. A simplified technique is proposed to derive high-resolution maps of TCO in the tropics even in the absence of tropopause-level clouds. This promising approach requires only total ozone gridded measurements and utilizes the small variability observed in TCO near the dateline. This technique has an advantage compared to the CCD method because the latter requires high

  3. Bayesian spatial models: Applications for tropospheric ozone data

    NASA Astrophysics Data System (ADS)

    Menezes, Kim Anne

    1999-12-01

    This research addresses issues pertaining to trend estimation in tropospheric ozone data as well as estimation of the spatial correlation structure of these data collected at multiple monitoring sites. Assessing long-term trends in tropospheric ozone data is imperative because of its adverse effect on human health and on agricultural crops. Moreover, we also estimate the spatial correlation structure of such data, which is essential for spatial trend estimation, spatial prediction and for redesigning an existing network of stations. The U.S. Environmental Protection Agency's (EPA) National Ambient Air Quality Standard for ozone is stated in terms of exceedances of a specified threshold level. Therefore, the EPA is concerned with the long-term trend in the probability of an exceedance. In the first part of my dissertation we build a multivariate nonparametric probit regression model estimated within a hierarchical Bayes framework to model the probability of an exceedance after allowing for the effects of changing meteorological conditions. There are three advantages to using this model. First, the trends estimated at each site in a region can be separated into a city-wide component that is common to all sites, and a site-specific component that is unique to the individual site. Second, the hierarchical Bayes framework allows for the ``borrowing of strength'' from data collected at other monitoring sites to increase the information available regarding the trend at each individual site. Third, the nonparametric model does not require the a priori specification of the functional forms relating the probability of an exceedance to the meteorological variables. Ozone data from four Houston monitoring sites for the period 1981-1997 are analyzed. In the second part we provide a penalized likelihood approach to estimating the spatial correlation structure when the assumptions of stationarity and isotropy are violated. The spatial correlation structure under these

  4. IASI measurements of tropospheric ozone over Chinese megacities: Beijing, Shanghai, and Hong Kong

    NASA Astrophysics Data System (ADS)

    Dufour, G.; Eremenko, M.; Orphal, J.; Flaud, J.-M.

    2009-11-01

    IASI observations of tropospheric ozone over Beijing, Shanghai and Hong Kong during one year have been analysed, demonstrating the capability of space-borne infrared nadir measurements to probe both seasonal and daily variations of lower tropospheric ozone around megacities on the regional scale. The monthly variations of lower tropospheric ozone retrieved from IASI show the influence of the Asian summer monsoon that brings clean air masses from the Pacific during summer. They exhibit indeed a sharp ozone maximum in late spring and early summer (May-June) followed by a summer minimum. The time periods and the intensities of the maxima and of the decreases are latitude-dependent: they are more pronounced in Hong Kong and Shanghai than in Beijing. Moreover, IASI provides the opportunity to follow the spatial variations of ozone over the surroundings of each megacity as well as its daily variability. We show indeed that the large lower tropospheric ozone amounts observed with IASI are consistent with the highest population density distribution in each region, thus suggesting the anthropogenic origin of the large ozone amounts observed. Finally an analysis of the mean daily ozone profiles over each region for selected periods with high ozone events shows that the high ozone amounts observed during winter are likely related to descents of ozone-rich air from the stratosphere whereas in spring and summer the tropospheric ozone is likely enhanced by photochemical production in polluted areas and/or in fire plumes.

  5. Satellite observation of lowermost tropospheric ozone by multispectral synergism of IASI thermal infrared and GOME-2 ultraviolet measurements over Europe

    NASA Astrophysics Data System (ADS)

    Cuesta, J.; Eremenko, M.; Liu, X.; Dufour, G.; Cai, Z.; Hoepfner, M.; von Clarmann, T.; Sellitto, P.; Foret, G.; Gaubert, B.; Beekmann, M.; Orphal, J. J.; Chance, K.; Spurr, R. J.; Flaud, J.

    2013-12-01

    Lowermost tropospheric ozone is a major factor determining air quality, which directly affects human health in megacities and causes damages to ecosystems. Monitoring tropospheric ozone is a key societal issue which can be addressed at the regional scale by spaceborne observation. However, current satellite retrievals of tropospheric ozone using uncoupled either ultraviolet (UV) or thermal infrared (TIR) observations show limited sensitivity to ozone at the lowermost troposphere (LMT, up to 3 km asl of altitude above sea level), which is the major concern for air quality. In this framework, we have developed a new multispectral approach for observing lowermost tropospheric ozone from space by synergism of atmospheric TIR radiances observed by IASI and earth UV reflectances measured by GOME-2. Both instruments are onboard the series of MetOp satellites (in orbit since 2006 and expected until 2022) and their scanning capabilities offer global coverage every day, with a relatively fine ground pixel resolution (12-km-diameter pixels spaced by 25 km for IASI at nadir). Our technique uses altitude-dependent Tikhonov-Phillips-type constraints, which optimize sensitivity to lower tropospheric ozone. It integrates the VLIDORT and KOPRA radiative transfer codes for simulating UV reflectance and TIR radiance, respectively. We have used our method to analyze real observations over Europe during an ozone pollution episode in the summer of 2009. The results show that the multispectral synergism of IASI (TIR) and GOME-2 (UV) enables the observation of the spatial distribution of ozone plumes in the LMT, in good agreement with the CHIMERE regional chemistry-transport model. In this case study, when high ozone concentrations extend vertically above 3 km asl, they are similarly observed over land by both the multispectral and IASI retrievals. On the other hand, ozone plumes located below 3 km asl are only clearly depicted by the multispectral retrieval (both over land and over ocean

  6. The impact of tropospheric planetary wave variability on stratospheric ozone

    SciTech Connect

    McElroy, Michael B.; Schneider, Hans R.

    2002-06-25

    The goal of this project was to improve understanding of the role of the stratosphere in inducing long-term variations of the chemical composition of the troposphere. Changes in stratospheric transport occur on decadel timescales in response to changes in the structure of planetary wave patterns, forced in the troposphere. For many important tracers, such as column amounts of ozone, this variability of the transport leads to changes with signatures very similar to those induced by anthropogenic releases of chemicals into the atmosphere. During this project, a new interactive two-dimensional model of the dynamics, chemistry and radiation of the stratosphere was developed. The model was used to interpret available data of tracers. It was found that a fairly coherent picture of tracer distributions is obtained when a layer of reduced gravity wave drag is assumed for the lower stratosphere. The results suggest that the power of models to predict variability in tracer transport in the upper troposphere and lower stratosphere is limited until current theories of gravity wave breaking have been refined.

  7. Analysis of a 7 year tropospheric ozone vertical distribution at the Observatoire de Haute Provence

    NASA Technical Reports Server (NTRS)

    Beekmann, Matthias; Ancellet, Gerard; Megie, Gerard

    1994-01-01

    A seven year (1984-90) climatology of tropospheric vertical ozone soundings, performed by electrochemical sondes at the OHP (44 deg N, 6 deg E, 700 m ASL) in Southern France, is presented. Its seasonal variation shows a broad spring/summer maximum in the troposphere. The contribution of photochemical ozone production and transport from the stratosphere to this seasonal variation are studied by a correlative analysis of ozone concentrations and meteorological variables, with emphasis on potential vorticity. This analysis shows the impact of dynamical and photochemical processes on the spatial and temporal ozone variability. In particular, a positive correlation (r = 04.0, significance greater than 99.9 percent) of ozone with potential vorticity is observed in the middle troposphere, reflecting the impact of stratosphere-troposphere exchange on the vertical ozone distribution.

  8. The effect of ozone depletion on the Southern Annular Mode and stratosphere-troposphere coupling

    NASA Astrophysics Data System (ADS)

    Dennison, Fraser; McDonald, Adrian; Morgenstern, Olaf

    2015-04-01

    The aim of this study is to investigate the influence of ozone depletion and recovery on the Southern Annular Mode (SAM) and stratosphere-troposphere coupling. Using the NIWA-UKCA chemistry-climate model, we compare reference runs with forcing due to greenhouse gases and ozone depleting substances to sensitivity simulations in which ozone depleting substances are fixed at their 1960 levels. We find that ozone depletion leads to an increased frequency of extreme anomalies and increased persistence of the SAM in the stratosphere as well as stronger, more persistent stratosphere-troposphere coupling. This change in the strength of the stratosphere-troposphere coupling has implications for extended range weather forecasting. Currently the stratosphere provides an appreciable amount of predictability to the troposphere on time scales of one or two months, however we find that this effect reduces over time as stratospheric ozone recovers to pre-ozone hole levels towards the latter part of this century.

  9. "Cloud Slicing" : A New Technique to Derive Tropospheric Ozone Profile Information from Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    A new technique denoted cloud slicing has been developed for estimating tropospheric ozone profile information. All previous methods using satellite data were only capable of estimating the total column of ozone in the troposphere. Cloud slicing takes advantage of the opaque property of water vapor clouds to ultraviolet wavelength radiation. Measurements of above-cloud column ozone from the Nimbus 7 total ozone mapping spectrometer (TOMS) instrument are combined together with Nimbus 7 temperature humidity and infrared radiometer (THIR) cloud-top pressure data to derive ozone column amounts in the upper troposphere. In this study tropical TOMS and THIR data for the period 1979-1984 are analyzed. By combining total tropospheric column ozone (denoted TCO) measurements from the convective cloud differential (CCD) method with 100-400 hPa upper tropospheric column ozone amounts from cloud slicing, it is possible to estimate 400-1000 hPa lower tropospheric column ozone and evaluate its spatial and temporal variability. Results for both the upper and lower tropical troposphere show a year-round zonal wavenumber 1 pattern in column ozone with largest amounts in the Atlantic region (up to approx. 15 DU in the 100-400 hPa pressure band and approx. 25-30 DU in the 400-1000 hPa pressure band). Upper tropospheric ozone derived from cloud slicing shows maximum column amounts in the Atlantic region in the June-August and September-November seasons which is similar to the seasonal variability of CCD derived TCO in the region. For the lower troposphere, largest column amounts occur in the September-November season over Brazil in South America and also southern Africa. Localized increases in the tropics in lower tropospheric ozone are found over the northern region of South America around August and off the west coast of equatorial Africa in the March-May season. Time series analysis for several regions in South America and Africa show an anomalous increase in ozone in the lower

  10. The impact of the stratospheric ozone distribution on large-scale tropospheric systems over South America

    NASA Astrophysics Data System (ADS)

    Da Silva, L. A.; Vieira, L. A.; Prestes, A.; Pacini, A. A.; Rigozo, N. R.

    2013-12-01

    Most of the large-scale changes of the climate can be attributed to the cumulative impact of the human activities since the beginning of the industrial revolution. However, the impact of natural drivers to the present climate change is still under debate, especially on regional scale. These regional changes over South America can potentially affect large vulnerable populations in the near future. Here, we show that the distribution of the stratospheric ozone can affect the climate patterns over South America and adjoin oceans. The impact of the stratospheric ozone distribution was evaluated employing the Global Atmospheric-Ocean Model developed by the Goddard Institute for Space Studies (GISS Model E). We conducted two numerical experiments. In the first experiment we used a realistic distribution of the stratospheric ozone, while in the second experiment we employed a uniform longitudinal distribution. We have integrated each model over 60 years. We find that the distribution of stratospheric ozone has a strong influence on the Intertropical Convergence Zone (ITCZ) and South Atlantic Convergence Zone (SACZ). However, the Upper Tropospheric Cyclonic Vortex (UTCV) is not affected by the ozone's distribution.

  11. Tropospheric Ozone Increases over the Southern Africa Region: Bellwether for Rapid Growth in Southern Hemisphere Pollution?

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Balashov, Nikolay V.; Witte, J. C.; Coetzee, J. G. R.; Thouret, V.; Posny, F.

    2014-01-01

    Increases in free-tropospheric (FT) ozone based on ozonesonde records from the early 1990s through 2008 over two subtropical stations, Irene (near Pretoria, South Africa) and Réunion (21 deg. S, 55 deg. E; approx. 2800 km NE of Irene in the Indian Ocean), have been reported. Over Irene a large increase in the urban-influenced boundary layer (BL, 1.5-4 km) was also observed during the 18-year period, equivalent to 30%decade-1. Here we show that the Irene BL trend is at least partly due to a gradual change in the sonde launch times from early morning to the midday period. The FT ozone profiles over Irene in 1990-2007 are re-examined, filling in a 1995-1999 gap with ozone profiles taken during the Measurements of Ozone by Airbus In-service Aircraft (MOZAIC) project over nearby Johannesburg. A multivariate regression model that accounts for the annual ozone cycle, El Niño-Southern Oscillation (ENSO) and possible tropopause changes was applied to monthly averaged Irene data from 4 to 11 km and to 1992-2011 Réunion sonde data from 4 to 15 km. Statistically significant trends appear predominantly in the middle and upper troposphere (UT; 4-11 km over Irene, 4-15 km over Réunion) in winter (June-August), with increases 1 ppbv yr(exp. -1) over Irene and approx. 2 ppbv yr(exp. -1) over Réunion. These changes are equivalent to approx. 25 and 35-45%decade( exp. -1), respectively. Both stations also display smaller positive trends in summer, with a 45%decade(exp. -1) ozone increase near the tropopause over Réunion in December. To explain the ozone increases, we investigated a time series of dynamical markers, e.g., potential vorticity (PV) at 330-350 K. PV affects UT ozone over Irene in November-December but displays little relationship with ozone over Réunion. A more likely reason for wintertime FT ozone increases over Irene and Réunion appears to be long-range transport of growing pollution in the Southern Hemisphere. The ozone increases are consistent with trajectory

  12. Is tropospheric ozone over southern Africa really increasing? Evidence from sonde and aircraft profiles

    NASA Astrophysics Data System (ADS)

    Thompson, A. M.; Balashov, N. V.; Witte, J. C.; Coetzee, J. G. R.; Thouret, V.; Posny, F.

    2014-04-01

    Ozonesonde records from the early 1990's through 2008 over two subtropical stations, Irene (near Pretoria, South Africa) and Réunion Island (21° S, 55° W, ~3500 km NE of Irene in the Indian Ocean) were reported to exhibit free tropospheric (FT) ozone increases. Over Irene a large increase in the urban-influenced boundary layer (BL, 1.5-4 km) was also observed during the 18 year period, equivalent to 30% decade-1. Here we show that the Irene BL trend is at least partly due to a gradual change in the sonde launch times from early morning to the midday period. The FT ozone profiles over Irene in 1990-2007 are re-examined, filling in a 1995-1999 gap with ozone profiles taken by Measurements of Ozone by Airbus In-service Aircraft (MOZAIC) over nearby Johannesburg. A multivariate regression model that accounts for the annual ozone cycle, ENSO and possible tropopause changes was applied to monthly averaged Irene data from 4-11 km and to 1992-2011 Réunion sonde data from 4-15 km. Statistically significant trends appear predominantly in the middle and upper troposphere (UT, 4-11 km over Irene, 5-13 km over Réunion) in winter (June-August), with increases ~1 ppbv yr-1 over Irene and ~2 ppbv yr-1 over Réunion. These changes are equivalent to ~25% and 40-50% decade-1, respectively. Both stations also display smaller positive trends in summer with a 50% decade-1 ozone increase near the tropopause over Réunion in December. To explain the ozone increases, we investigated a time series of dynamical markers, e.g., potential vorticity (PV) at 330-350 K. PV affects UT ozone over Irene in November-December but displays little relationship to ozone over Réunion. A more likely reason for wintertime FT ozone increases over Irene and Réunion appears to be long-range transport of growing pollution in the Southern Hemisphere. The ozone increases are consistent with trajectory origins of air parcels sampled by the sondes and with recent NOx emissions trends estimated for Africa

  13. Tropospheric ozone increases over the southern Africa region: bellwether for rapid growth in Southern Hemisphere pollution?

    NASA Astrophysics Data System (ADS)

    Thompson, A. M.; Balashov, N. V.; Witte, J. C.; Coetzee, J. G. R.; Thouret, V.; Posny, F.

    2014-09-01

    Increases in free-tropospheric (FT) ozone based on ozonesonde records from the early 1990s through 2008 over two subtropical stations, Irene (near Pretoria, South Africa) and Réunion (21° S, 55° E; ~2800 km NE of Irene in the Indian Ocean), have been reported. Over Irene a large increase in the urban-influenced boundary layer (BL, 1.5-4 km) was also observed during the 18-year period, equivalent to 30% decade-1. Here we show that the Irene BL trend is at least partly due to a gradual change in the sonde launch times from early morning to the midday period. The FT ozone profiles over Irene in 1990-2007 are re-examined, filling in a 1995-1999 gap with ozone profiles taken during the Measurements of Ozone by Airbus In-service Aircraft (MOZAIC) project over nearby Johannesburg. A multivariate regression model that accounts for the annual ozone cycle, El Niño-Southern Oscillation (ENSO) and possible tropopause changes was applied to monthly averaged Irene data from 4 to 11 km and to 1992-2011 Réunion sonde data from 4 to 15 km. Statistically significant trends appear predominantly in the middle and upper troposphere (UT; 4-11 km over Irene, 4-15 km over Réunion) in winter (June-August), with increases ~1 ppbv yr-1 over Irene and ~2 ppbv yr-1 over Réunion. These changes are equivalent to ~25 and 35-45% decade-1, respectively. Both stations also display smaller positive trends in summer, with a 45% decade-1 ozone increase near the tropopause over Réunion in December. To explain the ozone increases, we investigated a time series of dynamical markers, e.g., potential vorticity (PV) at 330-350 K. PV affects UT ozone over Irene in November-December but displays little relationship with ozone over Réunion. A more likely reason for wintertime FT ozone increases over Irene and Réunion appears to be long-range transport of growing pollution in the Southern Hemisphere. The ozone increases are consistent with trajectory origins of air parcels sampled by the sondes and

  14. Tropospheric Ozone Pollution Transport Traced from the TOMS (Total Ozone Mapping Spectrometer) Instrument During the Nashville-1999 Campaign

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Frolov, A. D.; Hudson, R. D.; Witte, J. C.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Over the past several years, we have developed two new tropospheric ozone retrievals from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument that are of sufficient resolution to follow pollution episodes. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMS-direct method [("TDOT" = TOMS Direct Ozone in the Troposphere; Frolov et al., 2000] represents a new algorithm that uses TOMS radiances directly (i.e., not previously processed for TOMS ozone) to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution. These events tend to occur in certain meteorological regimes. For example, mid-latitude pollution usually occurs on the backside of subtropical fronts, as low pv, usually moist air intrudes to the extra-tropics. July 1999 was a month characterized by robust pollution in the eastern US, with high ozone, as detected by TOMS, originating over south central states and moving up the Atlantic seaboard. This corresponds to 50-80 DU in tropospheric ozone column depth. In most cases, further transport occurred to the North Atlantic, with ozone plumes traveling to western Europe in 4-5 days. Examples of high ozone and transit across boundaries within the US, as well as US->Europe, give a regional context for model results and field measurements taken in the SE US during the Nashville-1999 campaign period. Validation of the TDOT maps is made with ozonesondes taken during that time. TDOT maps also show ozone pollution from Asia traveling to the western US in July 1999.

  15. Tropospheric ozone retrieval by using SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Ladstätter-Weissenmayer, Annette; Ebojie, Felix; Rozanov, Alexei; Burrows, John

    2014-05-01

    Tropospheric ozone is photochemically produced during pollution events and transported from the stratosphere towards the troposphere. It is the third most important green house gases and the main component of summer smog. Global covered satellite measurements are well suitable to investigate sources, sinks, and transport mechanisms of tropospheric ozone in a global view, and to study a characteristic behaviour of the tropospheric ozone in regions. However, the usage of satellite data is associated to a large uncertainty as 90% ozone is located in the stratosphere and only the remaining part of 10% can be observed in the troposphere. The limb-nadir matching (LNM) technique is one of the methods suitable to retrieve tropospheric ozone distributions from space borne observations of the scattered solar light in the UV-visible spectral range. In this study we apply the LNM approach to alternating limb and nadir measurements performed by the SCIAMACHY instrument. A precise tropopause height is used to subtract the stratospheric ozone from the total ozone amount for each matching point. The focus of this work is to reduce the uncertainty of the resulting tropospheric ozone distributions by analysing possible error sources, refining both limb and nadir retrievals and the matching technique.

  16. Evaluation of ACCMIP Outgoing Longwave Radiation from Tropospheric Ozone Using TES Satellite Observations.

    NASA Technical Reports Server (NTRS)

    Bowman, Kevin W.; Shindell, Drew Todd; Worden, H. M.; Lamarque, J. F.; Young, P. J.; Stevenson, D. S.; Qu, Z.; delaTorre, M.; Bergmann, D.; Cameron-Smith, P. J.; Collins, W. J.; Doherty, R.; Dalsoren, S. B.; Faluvegi, G.; Folberth, G.; Horowitz, L. W.; Josse, B. M.; Lee, Y. H.; MacKenzie, I. A.; Myhre, G.; Nagashima, T.; Naik, V.; Strode, S. A.; Kulawik, S. S..; Worden, J. R.

    2013-01-01

    We use simultaneous observations of tropospheric ozone and outgoing longwave radiation (OLR) sensitivity to tropospheric ozone from the Tropospheric Emission Spectrometer (TES) to evaluate model tropospheric ozone and its effect on OLR simulated by a suite of chemistry-climate models that participated in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The ensemble mean of ACCMIP models show a persistent but modest tropospheric ozone low bias (5-20 ppb) in the Southern Hemisphere (SH) and modest high bias (5-10 ppb) in the Northern Hemisphere (NH) relative to TES ozone for 2005-2010. These ozone biases have a significant impact on the OLR. Using TES instantaneous radiative kernels (IRK), we show that the ACCMIP ensemble mean tropospheric ozone low bias leads up to 120mW/ sq. m OLR high bias locally but zonally compensating errors reduce the global OLR high bias to 39+/- 41mW/ sq. m relative to TES data. We show that there is a correlation (Sq. R = 0.59) between the magnitude of the ACCMIP OLR bias and the deviation of the ACCMIP preindustrial to present day (1750-2010) ozone radiative forcing (RF) from the ensemble ozone RF mean. However, this correlation is driven primarily by models whose absolute OLR bias from tropospheric ozone exceeds 100mW/ sq. m. Removing these models leads to a mean ozone radiative forcing of 394+/- 42mW/ sq. m. The mean is about the same and the standard deviation is about 30% lower than an ensemble ozone RF of 384 +/- 60mW/ sq. m derived from 14 of the 16 ACCMIP models reported in a companion ACCMIP study. These results point towards a profitable direction of combining satellite observations and chemistry-climate model simulations to reduce uncertainty in ozone radiative forcing.

  17. Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

    NASA Astrophysics Data System (ADS)

    Olsen, Mark A.; Wargan, Krzysztof; Pawson, Steven

    2016-06-01

    We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Niño Southern Oscillation (ENSO) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Niño 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9-year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes.

  18. TOLNET - A Tropospheric Ozone Lidar Profiling Network for Satellite Continuity and Process Studies

    NASA Astrophysics Data System (ADS)

    Newchurch, Michael J.; Kuang, Shi; Leblanc, Thierry; Alvarez, Raul J.; Langford, Andrew O.; Senff, Christoph J.; Burris, John F.; McGee, Thomas J.; Sullivan, John T.; DeYoung, Russell J.; Al-Saadi, Jassim; Johnson, Matthew; Pszenny, Alex

    2016-06-01

    Ozone lidars measure continuous, high-resolution ozone profiles critical for process studies and for satellite validation in the lower troposphere. However, the effectiveness of lidar validation by using single-station data is limited. Recently, NASA initiated an interagency ozone lidar observation network under the name TOLNet to promote cooperative multiple-station ozone-lidar observations to provide highly timeresolved (few minutes) tropospheric-ozone vertical profiles useful for air-quality studies, model evaluation, and satellite validation. This article briefly describes the concept, stations, major specifications of the TOLNet instruments, and data archiving.

  19. Improvement of OMI Ozone Profile Retrievals in the Troposphere and Lower Troposphere by the Use of the Tropopause-Based Ozone Profile Climatology

    NASA Technical Reports Server (NTRS)

    Bak, Juseon; Liu, X.; Wei, J.; Kim, J. H.; Chance, K.; Barnet, C.

    2011-01-01

    An advance algorithm based on the optimal estimation technique has beeen developed to derive ozone profile from GOME UV radiances and have adapted it to OMI UV radiances. OMI vertical resolution : 7-11 km in the troposphere and 10-14 km in the stratosphere. Satellite ultraviolet measurements (GOME, OMI) contain little vertical information for the small scale of ozone, especially in the upper troposphere (UT) and lower stratosphere (LS) where the sharp O3 gradient across the tropopause and large ozone variability are observed. Therefore, retrievals depend greatly on the a-priori knowledge in the UTLS

  20. TOLNet - A Tropospheric Ozone Lidar Profiling Network for Satellite Continuity and Process Studies

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; Kuang, Shi; Wang, Lihua; LeBlanc, Thierry; Alvarez II, Raul J.; Langford, Andrew O.; Senff, Christoph J.; Brown, Steve; Johnson, Bryan; Burris, John F.; McGee, Thomas J.; Sullivan, John T.

    2015-01-01

    NASA initiated an interagency ozone lidar observation network under the name TOLNet to promote cooperative multiple-station ozone-lidar observations to provide highly time-resolved (few minutes) tropospheric-ozone vertical profiles useful for air-quality studies, model evaluation, and satellite validation.

  1. Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

    NASA Technical Reports Server (NTRS)

    Cooper, O. R.; Parrish, D. D.; Stohl, A.; Trainer, M.; Nedelec, P.; Thouret, V.; Cammas, J. P.; Oltmans, S. J.; Johnson, B. J.; Tarasick, D.; Leblanc, T.; McDermid, I. S.; Jaffe, D.; Gao, R.; Stith, J.; Ryerson, T.; Aikin, K.; Campos, T.; Weinheimer, A.; Avery, M. A.

    2010-01-01

    In the lowermost layer of the atmosphere - the troposphere - ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity1. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA s compliance with its ozone air quality standard.

  2. Altitude troposphere ozone profiles over Kyiv-Goloseyev station by simultaneous Umkehr and FTIR observations

    NASA Astrophysics Data System (ADS)

    Milinevsky, Gennadi; Shavrina, Angelina; Udodov, Evgeny; Liptuga, Anatoly; Kyslyi, Volodymyr; Danylevsky, Vassyl; Kravchenko, Volodymyr; Ivanov, Yuri; Synyavski, Ivan; Romanyuk, Yaroslav; Pavlenko, Yakov; Veles, Oleksandr

    2016-04-01

    Total ozone column and ozone profile data have been obtained from both: (1) standard Dobson measurements and Umkehr method, and (2) using modeling of the ozone absorption spectral band profile near 9.6 microns with the MODTRAN4.3 Atmospheric Radiation Transfer Model based on the HITRAN molecular absorption database from Fourier transform infrared spectroscopy (FTIR) observations. The simultaneous ground-based Dobson/Umkehr and FTIR ozone observations have been performed in 2014-2015 at the mid-latitude Kyiv-Goloseyev KGV GAW station for joint altitude troposphere ozone profiles analysis. To retrieve ozone column estimates and ozone profiles from FTIR observations, we used the satellite Aqua-AIRS water vapor, temperature and ozone profiles, and the simultaneous with FTIR observations the Umkehr ozone profiles and surface ozone measurements as input a priori information for the MODTRAN4.3 model. The altitude ozone profiles retrieved from Umkehr method and satellite measurements are in good correspondence in stratosphere layer. However the troposphere part of ozone profiles is uncertain and reproduced with large errors. Therefore we use the MODTRAN4.3 model for interpretation of observed FTIR absorption spectrum to retrieve and improve the troposphere part of ozone altitude distribution. The synergy of Umkehr, satellite and FTIR simultaneous observations including surface ozone measurements allows rendering the ozone profile features in troposphere that indicate the stratosphere-troposphere exchange processes. Season ozone profile variations observed from Umkehr measurements are discussed as well. This work was partly supported by the Polar FORCeS project no. 4012 of the Australian Antarctic Science Program.

  3. Use of satellite data to study tropospheric ozone in the tropics

    NASA Technical Reports Server (NTRS)

    Fishman, Jack; Minnis, Patrick; Reichle, Henry G., Jr.

    1986-01-01

    Three independent examples are discussed which suggest that photochemical ozone production in the troposphere can be observed in the tropics from an analysis of total ozone data. The first finding shows that the seasonal cycle of total columnar ozone is dominated by the seasonal cycle of tropospheric ozone, even though tropospheric ozone accounts for only 5-15 percent of the total ozone. Second, a case study is presented which shows that enhanced total ozone observed over the Amazon Basin can be associated with the presence of biomass burning. In situ measurements have confirmed that biomass burning does result in the production of photochemically generated ozone, analogous to the formation of 'smog' near industrialized areas. Third, an analysis of the distribution of carbon monoxide obtained from a Space Shuttle platform is strongly correlated with the concurrent distribution of total ozone between 5 deg S and 10 deg N. Because all of the sources of carbon monoxide are located in the troposphere, this finding likewise suggests that the gradients of total ozone at low latitudes must also reflect processes occurring in the troposphere.

  4. Large climate-induced changes in ultraviolet index and stratosphere-to-troposphere ozone flux

    NASA Astrophysics Data System (ADS)

    Hegglin, Michaela I.; Shepherd, Theodore G.

    2009-10-01

    Now that stratospheric ozone depletion has been controlled by the Montreal Protocol, interest has turned to the effects of climate change on the ozone layer. Climate models predict an accelerated stratospheric circulation, leading to changes in the spatial distribution of stratospheric ozone and an increased stratosphere-to-troposphere ozone flux. Here we use an atmospheric chemistry climate model to isolate the effects of climate change from those of ozone depletion and recovery on stratosphere-to-troposphere ozone flux and the clear-sky ultraviolet radiation index-a measure of potential human exposure to ultraviolet radiation. We show that under the Intergovernmental Panel on Climate Change moderate emissions scenario, global stratosphere-to-troposphere ozone flux increases by 23% between 1965 and 2095 as a result of climate change. During this time, the clear-sky ultraviolet radiation index decreases by 9% in northern high latitudes-a much larger effect than that of stratospheric ozone recovery-and increases by 4% in the tropics, and by up to 20% in southern high latitudes in late spring and early summer. The latter increase in the ultraviolet index is equivalent to nearly half of that generated by the Antarctic `ozone hole' that was created by anthropogenic halogens. Our results suggest that climate change will alter the tropospheric ozone budget and the ultraviolet index, which would have consequences for tropospheric radiative forcing, air quality and human and ecosystem health.

  5. Evaluation of lightning-induced tropospheric ozone enhancements observed by ozone lidar and simulated by WRF/Chem

    NASA Astrophysics Data System (ADS)

    Wang, Lihua; Follette-Cook, Melanie B.; Newchurch, M. J.; Pickering, Kenneth E.; Pour-Biazar, Arastoo; Kuang, Shi; Koshak, William; Peterson, Harold

    2015-08-01

    High spatial- and temporal-resolution ozone lidar profiles, in conjunction with ozonesonde and satellite observations, are well suited to characterize short-term ozone variations due to different physical and chemical processes, such as the impact of lightning-generated NOx (LNOx) on tropospheric ozone. This work presents the hourly variation of tropospheric-ozone profiles measured by an ozone lidar at the University of Alabama in Huntsville, on July 14, 18, and 27, 2011. These ozone lidar data are compared with two WRF/Chem simulations, one with lightning NO (LNO) emissions and the other without. On July 14, 2011, the ozone lidar observed an ozone laminar structure with elevated ozone concentrations of 65∼80 ppbv below 2 km, low ozone (50∼65) ppbv between 2 and 5 km, and high ozone up to 165 ppbv between 5 and 12 km AGL. WRF/Chem simulations, in conjunction with backward trajectory analysis, suggest that lightning events occurring within upwind regions resulted in an ozone enhancement of 28 ppbv at 7.5 km AGL over Huntsville. On July 27, LNO emissions were transported to Huntsville from upwind and account for 75% of NOx and an 8.3 ppbv of ozone enhancement at ∼10 km; the model overestimates ozone between 2.5 and 5 km AGL.

  6. Cloud Slicing: A New Technique to Derive Upper Tropospheric Ozone from Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    A new technique denoted cloud slicing has been developed for measuring upper tropospheric ozone. Cloud slicing takes advantage of the opaque property of water vapor clouds to ultraviolet wavelength radiation. Measurements of above-cloud column ozone from the Nimbus 7 total ozone mapping spectrometer (TOMS) instrument are combined together with Nimbus 7 temperature humidity and infrared radiometer (THIR) cloud-top pressure data to derive ozone column amounts in the upper troposphere. In this study tropical TOMS and THIR data for the period 1979-1984 are analyzed. By combining total tropospheric column ozone (denoted TCO) measurements from the convective cloud differential (CCD) method with 100-400 hPa upper tropospheric column ozone amounts from cloud slicing, it is possible to estimate 400-1000 hPa lower tropospheric column ozone and evaluate its spatial and temporal variability. Results for both the upper and lower tropical troposphere show a year-round zonal wave number 1 pattern in column ozone with largest amounts in the Atlantic region (up to 15 DU in the 100-400 hPa pressure band and around 25-30 DU in the 400-1000 hPa pressure band). Upper tropospheric ozone derived from cloud slicing shows maximum column amounts in the Atlantic region in the June-August and September-November seasons which is similar to the seasonal variability of CCD derived TCO in the region. For the lower troposphere, largest column amounts occur in the September-November season over Brazil in South America and also southern Africa. Localized increases in the tropics in lower tropospheric ozone are found over the northern region of South America around August and off the west coast of equatorial Africa in the March-May season. Time series analysis for several regions in South America and Africa show an anomalous increase in ozone in the lower troposphere around the month of March which is not observed in the upper troposphere. The eastern Pacific indicates weak seasonal variability of

  7. Tropospheric ozone column retrieval from OMI data by means of neural networks: a validation exercise with ozone soundings over Europe

    NASA Astrophysics Data System (ADS)

    Di Noia, Antonio; Sellitto, Pasquale; Del Frate, Fabio; Cervino, Marco; Iarlori, Marco; Rizi, Vincenzo

    2013-12-01

    The retrieval of the tropospheric ozone column from satellite data is very important for the characterization of tropospheric chemical and physical properties. However, the task of retrieving tropospheric ozone from space has to face with one fundamental difficulty: the contribution of the tropospheric ozone to the measured radiances is overwhelmed by a much stronger stratospheric signal, which has to be reliably filtered. The Tor Vergata University Earth Observation Laboratory has recently addressed this issue by developing a neural network (NN) algorithm for tropospheric ozone retrieval from NASA-Aura Ozone Monitoring Instrument (OMI) data. The performances of this algorithm were proven comparable to those of more consolidated algorithms, such as Tropospheric Ozone Residual and Optimal Estimation. In this article, the results of a validation of this algorithm with measurements performed at six European ozonesonde sites are shown and critically discussed. The results indicate that systematic errors, related to the tropopause pressure, are present in the current version of the algorithm, and that including the tropopause pressure in the NN input vector can compensate for these errors, enhancing the retrieval accuracy significantly.

  8. Investigations of Stratosphere-Troposphere Exchange of Ozone Derived From MLS Observations

    NASA Technical Reports Server (NTRS)

    Olsen, Mark A.; Schoeberl, Mark R.; Ziemke, Jerry R.

    2006-01-01

    Daily high-resolution maps of stratospheric ozone have been constructed using observations by MLS combined with trajectory information. These fields are used to determine the extratropical stratosphere-troposphere exchange (STE) of ozone for the year 2005 using two diagnostic methods. The resulting two annual estimates compare well with past model- and observational-based estimates. Initial analyses of the seasonal characteristics indicate that significant STE of ozone in the polar regions occurs only during spring and early summer. We also examine evidence that the Antarctic ozone hole is responsible for a rapid decrease in the rate of ozone STE during the SH spring. Subtracting the high-resolution stratospheric ozone fiom OMI total column measurements creates a high-resolution tropospheric ozone residual (HTOR) product. The HTOR fields are compared to the spatial distribution of the ozone STE. We show that the mean tropospheric ozone maxima tend to occur near locations of significant ozone STE. This suggests that STE may be responsible for a significant fraction of many mean tropospheric ozone anomalies.

  9. Spatial patterns of tropospheric ozone in the Mount Rainier region of the Cascade Mountains, USA

    USGS Publications Warehouse

    Brace, S.; Peterson, D.L.

    1998-01-01

    Few data exist on tropospheric ozone concentrations in rural and wildland areas of western Washington, U.S.A. We measured tropospheric ozone in Mount Rainier National Park and the Puget Sound region of Washington using electronic analyzers and passive samplers during the summers of 1994 and 1995. Electronic analyzers recorded hourly ozone concentrations from five locations between Seattle and Mount Rainier. Ozone concentrations generally increased with distance from Seattle, with maximum hourly concentrations recorded at Enumclaw (319 m elevation, 50 km SE of Seattle). Paradise (1650 m elevation, 100 km SE of Seattle) had the highest monthly mean concentration of all sites measured with analyzers. Diurnal patterns on high-ozone days indicate that concentrations at Paradise remain near 60 ppbv throughout the day, whereas ozone concentrations closer to Seattle had higher peaks during the afternoon but dropped to near zero at night. Passive ozone samplers were used to measure weekly average ozone exposures in four river drainages within Mount Rainier National Park, across an elevation gradient (420 a??2100 m). In most drainages, ozone levels increased with elevation, with highest average weekly ozone exposure (47 ppbv) recorded at 2100 m. Ozone concentrations are significantly higher in the western portion of the park, indicating that ozone exposure varies considerably over short distances. These data provide a reference point for air quality in western Washington and indicate that intensive sampling is necessary to quantify spatial patterns of tropospheric ozone in mountainous regions.

  10. Tropospheric Ozone from Assimilation of Aura Data using Different Definitions of the Tropopause

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Wargan, K.; Chang, L.-P.; Hayashi, H.; Pawson, S.; Pawson, Steven; Livesey, N.; Bhartia, P. K.

    2006-01-01

    Ozone data from Aura OMI and MLS instruments were assimilated into the general circulation model (GCM) constrained by assimilated meteorological fields from the Global Modeling and Assimilation Office at NASA Goddard. Properties of tropospheric ozone and their sensitivity to the definition of the tropopause are investigated. Three definitions of the tropopause are considered: (1) dynamical (using potential vorticity and potential temperature), (2) using temperature lapse rate, and (3) using a fixed ozone value. Comparisons of the tropospheric ozone columns using these tropopause definitions will be presented and evaluated against coincident profiles from ozone sondes. Assimilated ozone profiles are used to identify possible tropopause folding events, which are important for stratosphere-troposphere exchange. Each profile is searched for multiple levels at which ozone attains the value typical of the troposphere-stratosphere transition in order to identify possible tropopause folds. Constrained by the dynamics from a global model and by assimilation of Aura ozone data every 3-hours, this data set provides an opportunity to study ozone evolution in the upper troposphere and lower stratosphere with high temporal resolution.

  11. Long-term tropical tropospheric ozone column retrievals using the Convective Clouds Differential (CCD) technique

    NASA Astrophysics Data System (ADS)

    Leventidou, Elpida; Ebojie, Felix; Eichmann, Kai-Uwe; Weber, Mark; Burrows, John P.

    2015-04-01

    Ozone influences most of the chemical reactions in the troposphere.Its tropospheric abundance can be retrieved using space-borne observations of vertically integrated ozone and cloud heights. The Convective Clouds Differential (CCD) technique (Ziemke et al., 1998 and Valks et al., 2014) takes advantage of the frequent occurrence of convective clouds in the western Pacific region by subtracting above-cloud ozone of this region from clear-sky ozone elsewhere to derive global monthly mean tropospheric amount. An important assumption is that the above-cloud ozone in the western Pacific simulates the stratospheric ozone and that the stratospheric ozone field is invariant with longitude; which is approximately true in the tropics. A CCD algorithm has been developed and is applied to optical remote sensing observations from three satellite instruments, so that a unique long-term record of monthly averaged tropical (20∘S, 20∘N) tropospheric vertically integrated ozone (1995-2012) is created. The validation of the CCD results with tropospheric ozone data from ozonesondes (Tompson et al., 2003) and Limb-Nadir matching observations (Ebojie et al. 2014) will be presented.

  12. Lower-Tropospheric Ozone (LTO) derived from TOMS near mountainous regions

    NASA Astrophysics Data System (ADS)

    Newchurch, M. J.; Liu, X.; Kim, J. H.

    2001-01-01

    Using Total Ozone Mapping Spectrometer (TOMS) version-7 level-2 clear-sky (reflectivity ≤ 20%) ozone measurements corrected for aerosol effects and sea-glint errors, we derived Lower Tropospheric Ozone (LTO) west and east of the Andes, the Mexican and Rocky Mountains, the mountains in Africa and the Arabian Peninsula, New Guinea, and the Himalayan Mountains. The derived results agree reasonably well with the seasonality of LTO from ozonesonde observations at Boulder, Cristobal, Fiji, Java, and Tahiti. The LTO seasonality found in the biomass burning seasons characterized by the ATSR World Fire Atlas west and east of the Andes (23°S-2°N), east of the Mexican Mountains (15°-23°N), South Sudan (6°-14°N), South Africa (30°-28°S), and west of New Guinea is consistent with the influence of biomass burning on the formation of tropospheric ozone in these regions. The significant El Niño influence on LTO west of New Guinea is evident throughout several El Niño cycles. The spring maximum in ozone west of the Mexican Mountains, in western China, and west of the Andes (32°-23°S) is consistent with a stratospheric intrusion source. East of the Mexican Mountains (23°-30°N), both west and east of the Rocky Mountains, in north Sudan and Iraq, and in western China, high concentrations of ozone are found in these continental and coastal regions which are affected by anthropogenic sources. The maximum ozone in these regions usually occurs in the summer due to photochemical ozone production. A summer LTO minimum occurs in coastal regions west of the Andes and west of Mexico, due to ozone destruction in low NOx and high H2O marine environment. A summer minimum also occurs in south Sudan in the rainy season. The LTO in the northern tropics of South America (4°-10°N), Africa (1°S-2°N), and east of New Guinea (7°-3°S) experiences little seasonal variation.

  13. Late Summer Ozone Variability in the Lower Troposphere of the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Tsamalis, Christoforos; Papayannis, Alexandros; Ancellet, Gerard; Ravetta, François

    2016-06-01

    During the STAAARTE 96 Hellen aircraft campaign the lidar ALTO together with in situ measurements examined the ozone and aerosols variability in the lower troposphere over the Eastern Mediterranean region. Ozone mean value in the free troposphere (FT) measured from ALTO was 48 ppb, while it was 45 ppb from in situ observations; the aerosols mean scattering coefficient (550 nm) was 31 Mm-1. The FT ozone distributions of the two instruments are significantly different to distinct sampling. Air masses origin examination using the FLEXPART model for low and high FT ozone observations during late summer indicate that low ozone masses come from Mediterranean/North Africa regions travelling at low altitude, while high ozone masses emanate from Europe's middle or upper troposphere.

  14. Growth response to a changing environment-Impacts of tropospheric ozone dose on photosynthesis of Norway spruce forests in Austria

    NASA Astrophysics Data System (ADS)

    Liu, Xiaozhen; Pietsch, Stephan; Hasenauer, Hubert

    2010-05-01

    Tropospheric ozone is an important air pollutant, although plants have active defense strategies (e.g. antioxidants), the cumulative ozone dose may lead to chronic damages to plant tissues. Ozone enters into plants through stomata and reacts with other chemicals to create toxic compounds. This affects plant photosynthesis and may reduce CO2 fixation, and consequently growth. Open top cambers (OTC) are usually used to study the effects of elevated ozone levels on photosynthesis; whereas field studies with on site occurring ozone levels are rare. A recent modelling study on Norway spruce stands in Austria exhibited trends in model errors indicating that an increase in ozone dose leads to a reduction in volume increment. This study aims to explore how different ozone doses affect photosynthesis under field conditions and may translate into growth response for 12 stands of Norway spruce, distributed along an ozone concentration gradient across Austria. A LI-6400xt photosynthesis system was utilized to collect physiological parameters including net photosynthesis, stomata conductance, internal CO2 concentration, transpiration, etc. Chlorophyll fluorescence data was collected by using a PEA chlorophyll fluorescence meter, and chlorophyll content was measured. Morphological characteristics and soil samples were also analyzed. Ozone dose to leaf tissue was calculated from external ozone concentration, the conductance of the stomata to ozone, the leaf area index and the time span of the day when ozone uptake takes place. Our results confirm that increasing cumulative ozone dose reduces maximum assimilation rate and carboxylation efficiency under field conditions. Our final goal is to quantify how far this ozone induced reduction in assimilation power ultimately translates into a growth reduction of Norway spruce in Austria.

  15. Interpretation of tropospheric ozone variability in data with different vertical and temporal resolution

    NASA Astrophysics Data System (ADS)

    Petropavlovskikh, I. V.; Disterhoft, P.; Johnson, B. J.; Rieder, H. E.; Manney, G. L.; Daffer, W.

    2012-12-01

    This work attributes tropospheric ozone variability derived from the ground-based Dobson and Brewer Umkehr measurements and from ozone sonde data to local sources and transport. It assesses capability and limitations in both types of measurements that are often used to analyze long- and short-term variability in tropospheric ozone time series. We will address the natural and instrument-related contribution to the variability found in both Umkehr and sonde data. Validation of Umkehr methods is often done by intercomparisons against independent ozone measuring techniques such as ozone sounding. We will use ozone-sounding in its original and AK-smoothed vertical profiles for assessment of ozone inter-annual variability over Boulder, CO. We will discuss possible reasons for differences between different ozone measuring techniques and its effects on the derived ozone trends. Next to standard evaluation techniques we utilize a STL-decomposition method to address temporal variability and trends in the Boulder Umkehr data. Further, we apply a statistical modeling approach to the ozone data set to attribute ozone variability to individual driving forces associated with natural and anthropogenic causes. To this aim we follow earlier work applying a backward selection method (i.e., a stepwise elimination procedure out of a set of total 44 explanatory variables) to determine those explanatory variables which contribute most significantly to the observed variability. We will present also some results associated with completeness (sampling rate) of the existing data sets. We will also use MERRA (Modern-Era Retrospective analysis for Research and Applications) re-analysis results selected for Boulder location as a transfer function in understanding of the effects that the temporal sampling and vertical resolution bring into trend and ozone variability analysis. Analyzing intra-annual variability in ozone measurements over Boulder, CO, in relation to the upper tropospheric

  16. UV Lidar Receiver Analysis for Tropospheric Sensing of Ozone

    NASA Technical Reports Server (NTRS)

    Pliutau, Denis; DeYoung, Russell J.

    2013-01-01

    A simulation of a ground based Ultra-Violet Differential Absorption Lidar (UV-DIAL) receiver system was performed under realistic daytime conditions to understand how range and lidar performance can be improved for a given UV pulse laser energy. Calculations were also performed for an aerosol channel transmitting at 3 W. The lidar receiver simulation studies were optimized for the purpose of tropospheric ozone measurements. The transmitted lidar UV measurements were from 285 to 295 nm and the aerosol channel was 527-nm. The calculations are based on atmospheric transmission given by the HITRAN database and the Modern Era Retrospective Analysis for Research and Applications (MERRA) meteorological data. The aerosol attenuation is estimated using both the BACKSCAT 4.0 code as well as data collected during the CALIPSO mission. The lidar performance is estimated for both diffuseirradiance free cases corresponding to nighttime operation as well as the daytime diffuse scattered radiation component based on previously reported experimental data. This analysis presets calculations of the UV-DIAL receiver ozone and aerosol measurement range as a function of sky irradiance, filter bandwidth and laser transmitted UV and 527-nm energy

  17. An Improved Tropospheric Ozone Residual Product: Limitations and Applications

    NASA Astrophysics Data System (ADS)

    Witte, J. C.; Douglass, A. R.; Olsen, M. A.; Thompson, A. M.

    2012-12-01

    The Tropospheric Ozone Residual (TOR) product is derived from Aura's Ozone (O3) Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS). OMI and MLS can estimate the TOR by subtracting the MLS stratospheric O3 from the OMI total column O3. Our improved TOR is a subset of the 2005-2012 database that takes into account (1) outliers that occur regularly in the mid to high latitudes, and (2) decreased sensitivity in the OMI O3 total column below clouds that contributes to a low-bias in the TOR compared to in-situ ozonesonde observations. To remove outliers, we have devised a filtering criteria based on the expected range of tropospheric O3 values from sondes, in combination with the tropospheric column fraction amount represented by the ratio of the OMI total column O3 to the MLS stratospheric column amount. We take advantage of a new cloud height algorithm - the optical centroid cloud pressure algorithm (OCCP) - that is sensitive to O3 below the nominal cloud-top pressure and can extend significantly below previous estimates of the assigned effective cloud height. Applying the new algorithm significantly improves the agreement with sondes for effective cloud pressures greater than 800-850 hPa, thereby reducing the need to assign a below-cloud O3 climatology. Finally, we assess the viability of applying the improved TOR for pollution studies and monitoring in the northern mid-latitudes. We examine O3 variability in the improved TOR over case study regions of Europe, Southeast Asia, and the US between 2005 and 2012, along with available sonde observations. We record the frequency, dates, and locations of the best and worst agreements with sondes to estimate when and where the TOR can be optimally used, and show cases where the variability of the TOR is representative of O3 variability in the boundary layer. A potential application of the improved TOR is to study inter-annual variability in summertime continental pollution outflow over regions of the US and

  18. Tropospheric temperature response to stratospheric ozone recovery in the 21st century

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; Fu, Q.

    2011-08-01

    Recent simulations predicted that the stratospheric ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a result of the decline of ozone depleting substances under the Montreal Protocol. Since the ozone layer is an important component in determining stratospheric and tropospheric-surface energy balance, the recovery of stratospheric ozone may have significant impact on tropospheric-surface climate. Here, using multi-model results from both the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC-AR4) models and coupled chemistry-climate models, we show that as ozone recovery is considered, the troposphere is warmed more than that without considering ozone recovery, suggesting an enhancement of tropospheric warming due to ozone recovery. It is found that the enhanced tropospheric warming is mostly significant in the upper troposphere, with a global and annual mean magnitude of ~0.41 K for 2001-2050. We also find that relatively large enhanced warming occurs in the extratropics and polar regions in summer and autumn in both hemispheres, while the enhanced warming is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced warming is also found at the surface. The global and annual mean enhancement of surface warming is about 0.16 K for 2001-2050, with maximum enhancement in the winter Arctic.

  19. A Global Climatology of Tropospheric and Stratospheric Ozone Derived from Aura OMI and MLS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J.R.; Chandra, S.; Labow, G.; Bhartia, P. K.; Froidevaux, L.; Witte, J. C.

    2011-01-01

    A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean! Asia region in summer months. High levels of tropospheric ozone in the northern hemisphere also persist in mid-latitudes over the eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the northern hemisphere in the latitude range 70degN-80degN in February-April and in the southern hemisphere around 40degS-50degS during months August-October. The largest stratospheric ozone abundances in the northern hemisphere lie over North America and eastern Asia extending eastward across the Pacific Ocean and in the southern hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere.

  20. Upper Tropospheric Ozone Between Latitudes 60S and 60N Derived from Nimbus 7 TOMS/THIR Cloud Slicing

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerald R.; Chandra, Sushil; Bhartia, P. K.

    2002-01-01

    This study evaluates the spatial distributions and seasonal cycles in upper tropospheric ozone (pressure range 200-500 hPa) from low to high latitudes (60S to 60N) derived from the satellite retrieval method called "Cloud Slicing." Cloud Slicing is a unique technique for determining ozone profile information in the troposphere by combining co-located measurements of cloud-top, pressure and above-cloud column ozone. For upper tropospheric ozone, co-located measurements of Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) above-cloud column ozone, and Nimbus 7 Temperature Humidity Infrared Radiometer (THIR) cloud-top pressure during 1979-1984 were incorporated. In the tropics, upper tropospheric ozone shows year-round enhancement in the Atlantic region and evidence of a possible semiannual variability. Upper tropospheric ozone outside the tropics shows greatest abundance in winter and spring seasons in both hemispheres with largest seasonal and largest amounts in the NH. These characteristics are similar to lower stratospheric ozone. Comparisons of upper tropospheric column ozone with both stratospheric ozone and a proxy of lower stratospheric air mass (i.e., tropopause pressure) from National Centers for Environmental Prediction (NCEP) suggest that stratosphere-troposphere exchange (STE) may be a significant source for the seasonal variability of upper tropospheric ozone almost everywhere between 60S and 60N except in low latitudes around 10S to 25N where other sources (e.g., tropospheric transport, biomass burning, aerosol effects, lightning, etc.) may have a greater role.

  1. DIAL Measurements of Free-Tropospheric Ozone Profiles in Huntsville, AL

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John; Newchurch, Michael J.; Johnson, Steve

    2007-01-01

    A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by NASA and the University of Alabama at Huntsville (UAH), measures free-tropospheric ozone profiles between 4-10 km. Located at 192 meters altitude in the Regional Atmospheric Profiling Laboratory for Discovery (RAPCD) on the UAH campus in Huntsville, AL, USA, this tropospheric ozone lidar operates under both daytime and nighttime conditions. Frequent coincident ozonesonde flights and theoretical calculations provide evidence to indicate the retrieval accuracy ranges from better than 8% at 4km to 40%-60% at 10 kin with 750-m vertical resolution and 30-minute integration. With anticipated improvements to allow retrievals at both higher and lower altitudes, this ozone lidar, along with co-located aerosol and Doppler Wind Lidars, will provide a unique 18 dataset for investigations of PBL and free-tropospheric chemical and dynamic processes.

  2. PREDICTING THE IMPACT OF TROPOSPHERIC OZONE ON ECOLOGICAL RESOURCES FOR SETTING NATIONAL AMBIENT AIR QUALITY STANDARDS

    EPA Science Inventory

    The Clean Air Act provides for establishing National Ambient Air Quality Standards (NAAQS) to protect public welfare (including crops, forests, ecosystems, and soils) from adverrse effects of air pollutants, including tropospheric ozone. The formulation of policies is science-bas...

  3. Tropospheric ozone (TOR) trend over three major inland Indian cities: Delhi, Hyderabad and Bangalore

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pavan S.; Ghude, Sachin D.; Bortoli, D.

    2010-10-01

    An analysis of tropospheric column ozone using the NASA Langley TOR data during 1979-2005 has been done to investigate the trend over major Indian cities Delhi, Hyderabad and Bangalore. India was under social democratic-based policies before 1990s. Economic Liberalization began in nineties which lead to a significant growth in industrial, energy and transport sectors in major cities. Our analysis shows that there is a systematic increase in the number of months with higher tropospheric ozone values after 1990. A comparison of TOR climatology before and after 1990 over these cities shows evidence of increase in the tropospheric ozone after 1990. Trend obtained from the model shows significant change during monsoon over Delhi and during pre-monsoon and post-monsoon over Hyderabad and Bangalore. The present analysis using TOR technique demonstrates the TOR potential to detect changes in tropospheric ozone over large cities which are impacted by large anthropogenic pollution.

  4. LABORATORY AND COMPUTATIONAL INVESTIGATIONS OF THE ATMOSPHERIC CHEMISTRY OF KEY OXIDATION PRODUCTS CONTROLLING TROPOSPHERIC OZONE FORMATION

    EPA Science Inventory

    Major uncertainties remain in our ability to identify the key reactions and primary oxidation products of volatile hydrocarbons that contribute to ozone formation in the troposphere. To reduce these uncertainties, computational chemistry, mechanistic and process analysis techniqu...

  5. MULTISCALE AIR QUALITY SIMULATION PLATFORM (MAQSIP): INITIAL APPLICATIONS AND PERFORMANCE FOR TROPOSPHERIC OZONE AND PARTICULATE MATTER

    EPA Science Inventory

    This manuscript provides an overview of the formulation, process considerations, and performance for simulating tropospheric ozone and particulate matter distributions of the Multiscale Air Quality Simulation Platform (MAQSIP). MAQSIP is a comprehensive atmospheric chemistry/tran...

  6. Climate Response to the Increase in Tropospheric Ozone since Preindustrial Times: A Comparison between Ozone and Equivalent CO2 Forcings

    NASA Technical Reports Server (NTRS)

    Mickley L. J.; Jacob, D. J.; Field, B. D.; Rind, D.

    2004-01-01

    We examine the characteristics of the climate response to anthropogenic changes in tropospheric ozone. Using a general circulation model, we have carried out a pair of equilibrium climate simulations with realistic present-day and preindustrial ozone distributions. We find that the instantaneous radiative forcing of 0.49 W m(sup -2) due to the increase in tropospheric ozone since preindustrial times results in an increase in global mean surface temperature of 0.28 C. The increase is nearly 0.4 C in the Northern Hemisphere and about 0.2 C in the Southern Hemisphere. The largest increases (greater than 0.8 C) are downwind of Europe and Asia and over the North American interior in summer. In the lower stratosphere, global mean temperatures decrease by about 0.2 C due to the diminished upward flux of radiation at 9.6 micrometers. The largest stratospheric cooling, up to 1.0 C, occurs over high northern latitudes in winter, with possibly important implications for the formation of polar stratospheric clouds. To identify the characteristics of climate forcing unique to tropospheric ozone, we have conducted two additional climate equilibrium simulations: one in which preindustrial tropospheric ozone concentrations were increased everywhere by 18 ppb, producing the same global radiative forcing as present-day ozone but without the heterogeneity; and one in which CO2 was decreased by 25 ppm relative to present day, with ozone at present-day values, to again produce the same global radiative forcing but with the spectral signature of CO2 rather than ozone. In the first simulation (uniform increase of ozone), the global mean surface temperature increases by 0.25 C, with an interhemispheric difference of only 0.03 C, as compared with nearly 0.2 C for the heterogeneous ozone increase. In the second simulation (equivalent CO2), the global mean surface temperature increases by 0.36 C, 30% higher than the increase from tropospheric ozone. The stronger surface warming from CO2 is

  7. Source attribution of interannual variability of tropospheric ozone over the southern hemisphere

    NASA Astrophysics Data System (ADS)

    Liu, J.; Rodriguez, J. M.; Logan, J. A.; Steenrod, S. D.; Douglass, A. R.; Olsen, M. A.; Wargan, K.; Ziemke, J. R.

    2015-12-01

    Both model simulations and GMAO assimilated ozone product derived from OMI/MLS show a high tropospheric ozone column centered over the south Atlantic from the equator to 30S. This ozone maximum extends eastward to South America and the southeast Pacific; it extends southwestward to southern Africa, south Indian Ocean. In this study, we use hindcast simulations from the GMI model of tropospheric and stratospheric chemistry, driven by assimilated MERRA meteorological fields, to investigate the factors controlling the interannual variations (IAV) of this ozone maximum during the last two decades. We also use various GMI tracer diagnostics, including a stratospheric ozone tracer to tag the impact of stratospheric ozone, and a tagged CO tracer to track the emission sources, to ascertain the contribution of difference processes to IAV in ozone at different altitudes, as well as partial columns above different pressure level. Our initial model analysis suggests that the IAV of the stratospheric contribution plays a major role on in the IAV of the upper tropospheric ozone and explains a large portion of variance during its winter season. Over the south Atlantic region, the IAV of surface emissions from both South America and southern Africa also contribute significantly to the IAV of ozone, especially in the middle and lower troposphere

  8. Global Distribution and Trends of Tropospheric Ozone: An Observation-Based Review

    NASA Technical Reports Server (NTRS)

    Cooper, O. R.; Parrish, D. D.; Ziemke, J.; Cupeiro, M.; Galbally, I. E.; Gilge, S.; Horowitz, L.; Jensen, N. R.; Lamarque, J.-F.; Naik, V.; Oltmans, S. J.; Schwab, J.; Shindell, D. T.; Thompson, A. M.; Thouret, V.; Wang, Y.; Zbinden, R. M.

    2014-01-01

    Tropospheric ozone plays a major role in Earth's atmospheric chemistry processes and also acts as an air pollutant and greenhouse gas. Due to its short lifetime, and dependence on sunlight and precursor emissions from natural and anthropogenic sources, tropospheric ozone's abundance is highly variable in space and time on seasonal, interannual and decadal time-scales. Recent, and sometimes rapid, changes in observed ozone mixing ratios and ozone precursor emissions inspired us to produce this up-to-date overview of tropospheric ozone's global distribution and trends. Much of the text is a synthesis of in situ and remotely sensed ozone observations reported in the peer-reviewed literature, but we also include some new and extended analyses using well-known and referenced datasets to draw connections between ozone trends and distributions in different regions of the world. In addition, we provide a brief evaluation of the accuracy of rural or remote surface ozone trends calculated by three state-of-the-science chemistry-climate models, the tools used by scientists to fill the gaps in our knowledge of global tropospheric ozone distribution and trends.

  9. "Cloud Slicing": A New Technique to Derive Upper Tropospheric Ozone from Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Ziemke, Jerald; Bhartia, Pawan K.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    A new technique called "cloud slicing" is introduced in this study to determine tropospheric ozone profile information. This method is unique because all previous methods incorporating satellite data were only capable of estimating the total column of ozone in the troposphere. Cloud slicing takes advantage of the opaque property of water vapor clouds to ultraviolet wavelength radiation. Measurements of above-cloud column ozone from the Nimbus 7 total ozone mapping spectrometer (TOMS) instrument are combined together with Nimbus 7 temperature humidity and infrared radiometer (THIR) cloud-top pressure data to derive ozone column amounts in the upper troposphere. In this study, tropical TOMS and THIR data for the period 1979-1984 are analyzed. Our investigation examines several case studies and illustrates the robust nature of this new technique for future satellite missions.

  10. The effect of ozone depletion on the Southern Annular Mode and stratosphere-troposphere coupling

    NASA Astrophysics Data System (ADS)

    Dennison, Fraser W.; McDonald, Adrian J.; Morgenstern, Olaf

    2015-07-01

    The aim of this study is to investigate the influence of ozone depletion and recovery on the Southern Annular Mode (SAM) and stratosphere-troposphere coupling. Using the National Institute of Water and Atmospheric Research-United Kingdom Chemistry and Aerosols chemistry-climate model, we compare reference runs that include forcing due to greenhouse gases and ozone-depleting substances to sensitivity simulations in which ozone-depleting substances are fixed at their 1960 levels. We find that ozone depletion leads to an increased frequency of extreme anomalies and increased persistence of the SAM in the stratosphere as well as stronger, more persistent stratosphere-troposphere coupling. Currently, the stratosphere provides an appreciable amount of predictability to the troposphere on timescales of 1 or 2 months; however, we find that this effect reduces over time as stratospheric ozone recovers to preozone hole levels toward the latter part of this century.

  11. The Response of Tropospheric Ozone to ENSO in Observations and a Chemistry-Climate Simulation

    NASA Technical Reports Server (NTRS)

    Oman, L. D.; Douglass, A. R.; Ziemke, J. R.; Waugh, D. W.; Rodriguez, J. M.; Nielsen, J. E.

    2012-01-01

    The El Nino-Southern Oscillation (ENSO) is the dominant mode of tropical variability on interannual time scales. ENSO appears to extend its influence into the chemical composition of the tropical troposphere. Recent results have revealed an ENSO induced wave-l anomaly in observed tropical tropospheric column ozone. This results in a dipole over the western and eastern tropical Pacific, whereby differencing the two regions produces an ozone anomaly with an extremely high correlation to the Nino 3.4 Index. We have successfully reproduced this result using the Goddard Earth Observing System Version 5 (GEOS-5) general circulation model coupled to a comprehensive stratospheric and tropospheric chemical mechanism forced with observed sea surface temperatures over the past 25 years. An examination of the modeled ozone field reveals the vertical contributions of tropospheric ozone to the column over the western and eastern Pacific region. We will show targeted comparisons with observations from NASA's Aura satellite Microwave Limb Sounder (MLS), and the Tropospheric Emissions Spectrometer (TES) to provide insight into the vertical structure of ozone changes. The tropospheric ozone response to ENSO could be a useful chemistry-climate model evaluation tool and should be considered in future modeling assessments.

  12. A joint data record of tropospheric ozone from Aura-TES and MetOp-IASI

    NASA Astrophysics Data System (ADS)

    Oetjen, Hilke; Payne, Vivienne H.; Neu, Jessica L.; Kulawik, Susan S.; Edwards, David P.; Eldering, Annmarie; Worden, Helen M.; Worden, John R.

    2016-08-01

    The Tropospheric Emission Spectrometer (TES) on Aura and Infrared Atmospheric Sounding Interferometer (IASI) on MetOp-A together provide a time series of 10 years of free-tropospheric ozone with an overlap of 3 years. We characterise the differences between TES and IASI ozone measurements and find that IASI's coarser vertical sensitivity leads to a small (< 5 ppb) low bias relative to TES for the free troposphere. The TES-IASI differences are not dependent on season or any other factor and hence the measurements from the two instruments can be merged, after correcting for the offset, in order to study decadal-scale changes in tropospheric ozone. We calculate time series of regional monthly mean ozone in the free troposphere over eastern Asia, the western United States (US), and Europe, carefully accounting for differences in spatial sampling between the instruments. We show that free-tropospheric ozone over Europe and the western US has remained relatively constant over the past decade but that, contrary to expectations, ozone over Asia in recent years does not continue the rapid rate of increase observed from 2004 to 2010.

  13. The Economic Impact of Climate, CO2, and Tropospheric Ozone Effects on Crop Yields in China, the US, and Europe

    NASA Astrophysics Data System (ADS)

    Reilly, J. M.; Felzer, B. S.; Paltsev, S.; Melillo, J. M.; Prinn, R. G.; Wang, C.; Sokolov, A. P.; Wang, X.

    2004-12-01

    Multiple environmental changes that may occur over the next century will affect crop productivity. Some of these effects are likely to be positive (CO2 fertilization), some negative (tropospheric ozone damage), and some may be either positive or negative (temperature and precipitation). Climate effects may operate in either direction because the direction of change may differ across regions (more precipitation in some areas and less in others) and warming may increase growing season lengths in cold-limited growing areas while acting as a detriment to productivity in areas with already high temperatures. Previous work has shown the effects of these combined environmental changes on carbon sequestration in natural and managed systems, and valued these effects in terms of avoided costs of fossil fuel carbon abatement. The more direct and obvious economic effect, however, is the changes in crop yields implied by these vegetation effects. Here we use the MIT Integrated Global Systems Model (IGSM) to analyze the potential economic impact of changes in crop yields. For this work we have augmented the Emissions Prediction and Policy Analysis (EPPA) model by further disaggregating the agricultural sector. This allows us to simulate economic effects of changes in yield (i.e. the productivity of cropland) on the regional economies of the world, including impacts on agricultural trade. The EPPA model includes multiple channels of market-based adaptation, including input substitution and trade. We are thus able to examine the extent to which market forces contribute toward adaptation and thus modify the initial yield effects. We examine multiple scenarios where tropospheric ozone precursors are controlled or not, and where greenhouse gas emissions are abated or not. This allows us to consider how these policies interact. We focus on China, the US, and Europe which are currently regions with high levels of tropospheric ozone damage. We find significant negative effects of

  14. Development of a Portable, Ground-Based Ozone Lidar Instrument for Tropospheric Ozone Research and Educational Training

    NASA Technical Reports Server (NTRS)

    Chyba, Thomas; Zenker, Thomas

    1998-01-01

    The objective of this project is to develop a portable, eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar (DIAL) measurements in the troposphere. This prototype instrument is intended to operate at remote field sites and to serve as the basic unit for monitoring projects requiring multi-instrument networks, such as that discussed in the science plan for the Global Tropospheric Ozone Project (GTOP). This instrument will be based at HU for student training in lidar technology as well as atmospheric ozone data analysis and interpretation. It will be also available for off-site measurement campaigns and will serve as a test bed for further instrument development. Later development beyond this grant to extend the scientific usefulness of the instrument may include incorporation of an aerosol channel and upgrading the laser to make stratospheric ozone measurements. Undergraduate and graduate students have been and will be active participants in this research effort.

  15. Geospatial interpolation and mapping of tropospheric ozone pollution using geostatistics.

    PubMed

    Kethireddy, Swatantra R; Tchounwou, Paul B; Ahmad, Hafiz A; Yerramilli, Anjaneyulu; Young, John H

    2014-01-01

    Tropospheric ozone (O3) pollution is a major problem worldwide, including in the United States of America (USA), particularly during the summer months. Ozone oxidative capacity and its impact on human health have attracted the attention of the scientific community. In the USA, sparse spatial observations for O3 may not provide a reliable source of data over a geo-environmental region. Geostatistical Analyst in ArcGIS has the capability to interpolate values in unmonitored geo-spaces of interest. In this study of eastern Texas O3 pollution, hourly episodes for spring and summer 2012 were selectively identified. To visualize the O3 distribution, geostatistical techniques were employed in ArcMap. Using ordinary Kriging, geostatistical layers of O3 for all the studied hours were predicted and mapped at a spatial resolution of 1 kilometer. A decent level of prediction accuracy was achieved and was confirmed from cross-validation results. The mean prediction error was close to 0, the root mean-standardized-prediction error was close to 1, and the root mean square and average standard errors were small. O3 pollution map data can be further used in analysis and modeling studies. Kriging results and O3 decadal trends indicate that the populace in Houston-Sugar Land-Baytown, Dallas-Fort Worth-Arlington, Beaumont-Port Arthur, San Antonio, and Longview are repeatedly exposed to high levels of O3-related pollution, and are prone to the corresponding respiratory and cardiovascular health effects. Optimization of the monitoring network proves to be an added advantage for the accurate prediction of exposure levels. PMID:24434594

  16. Geospatial Interpolation and Mapping of Tropospheric Ozone Pollution Using Geostatistics

    PubMed Central

    Kethireddy, Swatantra R.; Tchounwou, Paul B.; Ahmad, Hafiz A.; Yerramilli, Anjaneyulu; Young, John H.

    2014-01-01

    Tropospheric ozone (O3) pollution is a major problem worldwide, including in the United States of America (USA), particularly during the summer months. Ozone oxidative capacity and its impact on human health have attracted the attention of the scientific community. In the USA, sparse spatial observations for O3 may not provide a reliable source of data over a geo-environmental region. Geostatistical Analyst in ArcGIS has the capability to interpolate values in unmonitored geo-spaces of interest. In this study of eastern Texas O3 pollution, hourly episodes for spring and summer 2012 were selectively identified. To visualize the O3 distribution, geostatistical techniques were employed in ArcMap. Using ordinary Kriging, geostatistical layers of O3 for all the studied hours were predicted and mapped at a spatial resolution of 1 kilometer. A decent level of prediction accuracy was achieved and was confirmed from cross-validation results. The mean prediction error was close to 0, the root mean-standardized-prediction error was close to 1, and the root mean square and average standard errors were small. O3 pollution map data can be further used in analysis and modeling studies. Kriging results and O3 decadal trends indicate that the populace in Houston-Sugar Land-Baytown, Dallas-Fort Worth-Arlington, Beaumont-Port Arthur, San Antonio, and Longview are repeatedly exposed to high levels of O3-related pollution, and are prone to the corresponding respiratory and cardiovascular health effects. Optimization of the monitoring network proves to be an added advantage for the accurate prediction of exposure levels. PMID:24434594

  17. A Multi-sensor Upper Tropospheric Ozone Product (MUTOP) based on TES ozone and GOES water vapor: derivation

    NASA Astrophysics Data System (ADS)

    Felker, S. R.; Moody, J. L.; Wimmers, A. J.; Osterman, G.; Bowman, K.

    2010-12-01

    The Tropospheric Emission Spectrometer (TES), a hyperspectral infrared instrument on the Aura satellite, retrieves a vertical profile of tropospheric ozone. However, polar-orbiting instruments like TES provide limited nadir-view coverage. This work illustrates the value of these observations when taken in context with information about synoptic-scale weather patterns. The goal of this study is to create map-view products of upper troposphere (UT) ozone through the integration of TES ozone measurements with two synoptic dynamical tracers of stratospheric influence: specific humidity derived from the GOES Imager, and potential vorticity from an operational forecast model. As a mixing zone between tropospheric and stratospheric reservoirs, the upper troposphere (UT) exhibits a complex chemical makeup. Determination of ozone mixing ratios in this layer is especially difficult without direct in-situ measurement. However, it is well understood that UT ozone is correlated with dynamical tracers like low specific humidity and high potential vorticity. Blending the advantages of two remotely sensed quantities (GOES water vapor and TES ozone) is at the core of the Multi-sensor Upper Tropospheric Ozone Product (MUTOP). Our approach results in the temporal and spatial coverage of a geostationary platform, a major improvement over individual polar overpasses, while retaining TES's ability to characterize UT ozone. Results suggest that over 70% of TES-observed UT ozone variability can be explained by correlation with the two dynamical tracers. MUTOP reproduces TES retrievals across the GOES-West domain with a root mean square error (RMSE) of 19.2 ppbv. There are several advantages to this multi-sensor derived product approach: (1) it is calculated from 2 operational fields (GOES specific humidity and GFS PV), so the layer-average ozone can be created and used in near real-time; (2) the product provides the spatial resolution and coverage of a geostationary platform as it depicts

  18. Drivers of changes in stratospheric and tropospheric ozone between year 2000 and 2100

    NASA Astrophysics Data System (ADS)

    Banerjee, A.; Maycock, A. C.; Archibald, A. T.; Abraham, N. L.; Telford, P.; Braesicke, P.; Pyle, J. A.

    2015-11-01

    A stratosphere-resolving configuration of the Met Office's Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in (a) greenhouse gases and climate, (b) ozone-depleting substances (ODSs) and (c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere-troposphere exchange of ozone (STE). Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production, leading to overall increases in the tropospheric ozone burden. This opposes the effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in both ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs.

  19. Drivers of changes in stratospheric and tropospheric ozone between year 2000 and 2100

    NASA Astrophysics Data System (ADS)

    Banerjee, Antara; Maycock, Amanda C.; Archibald, Alexander T.; Abraham, N. Luke; Telford, Paul; Braesicke, Peter; Pyle, John A.

    2016-03-01

    A stratosphere-resolving configuration of the Met Office's Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in (a) greenhouse gases and climate, (b) ozone-depleting substances (ODSs) and (c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere-troposphere exchange (STE) of ozone. Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production and act to increase the tropospheric ozone burden. This opposes the effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs.

  20. The effects of tropospheric ozone on net primary production and implications for climate change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone (O3) is a global air pollutant that causes billions of dollars in lost plant productivity annually. It is an important anthropogenic greenhouse gas, and as a secondary air pollutant, can persist at high concentrations in rural areas far from industrial sources. Ozone reduces plant...

  1. A multi-sensor upper tropospheric ozone product (MUTOP) based on TES Ozone and GOES water vapor: derivation

    NASA Astrophysics Data System (ADS)

    Felker, S. R.; Moody, J. L.; Wimmers, A. J.; Osterman, G.; Bowman, K.

    2011-07-01

    The Tropospheric Emission Spectrometer (TES), a hyperspectral infrared instrument on the Aura satellite, retrieves a vertical profile of tropospheric ozone. However, polar-orbiting instruments like TES provide limited nadir-view coverage. This work illustrates the value of these observations when taken in context with geostationary imagery describing synoptic-scale weather patterns. The goal of this study is to create map-view products of upper troposphere (UT) ozone through the integration of TES ozone measurements with two synoptic dynamic tracers of stratospheric influence: specific humidity derived from the GOES Imager water vapor absorption channel, and potential vorticity (PV) from an operational forecast model. As a mixing zone between tropospheric and stratospheric reservoirs, the upper troposphere (UT) exhibits a complex chemical makeup. Determination of ozone mixing ratios in this layer is especially difficult without direct in situ measurement. However, it is well understood that UT ozone is correlated with dynamical tracers like low specific humidity and high potential vorticity. Blending the advantages of two remotely sensed quantities (GOES water vapor and TES ozone) is at the core of the Multi-sensor Upper Tropospheric Ozone Product (MUTOP). Our results suggest that 72 % of TES-observed UT ozone variability can be explained by its correlation with dry air and high PV. MUTOP reproduces TES retrievals across the GOES-West domain with a root mean square error (RMSE) of 18 ppbv (part per billion by volume). There are several advantages to this multi-sensor derived product approach: (1) it is calculated from two operational fields (GOES specific humidity and GFS PV), so maps of layer-average ozone can be created and used in near real-time; (2) the product provides the spatial resolution and coverage of a geostationary image as it depicts the variable distribution of ozone in the UT; and (3) the 6 h temporal resolution of the derived product imagery allows

  2. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    NASA Astrophysics Data System (ADS)

    Chen, Min

    The increasing human activities have produced large amounts of air pollutants ejected into the atmosphere, in which atmospheric aerosols and tropospheric ozone are considered to be especially important because of their negative impacts on human health and their impacts on global climate through either their direct radiative effect or indirect effect on land-atmosphere CO2 exchange. This dissertation dedicates to quantifying and evaluating the aerosol and tropospheric ozone effects on global terrestrial ecosystem dynamics using a modeling approach. An ecosystem model, the integrated Terrestrial Ecosystem Model (iTem), is developed to simulate biophysical and biogeochemical processes in terrestrial ecosystems. A two-broad-band atmospheric radiative transfer model together with the Moderate-Resolution Imaging Spectroradiometer (MODIS) measured atmospheric parameters are used to well estimate global downward solar radiation and the direct and diffuse components in comparison with observations. The atmospheric radiative transfer modeling framework were used to quantify the aerosol direct radiative effect, showing that aerosol loadings cause 18.7 and 12.8 W m -2 decrease of direct-beam Photosynthetic Active Radiation (PAR) and Near Infrared Radiation (NIR) respectively, and 5.2 and 4.4 W m -2 increase of diffuse PAR and NIR, respectively, leading to a total 21.9 W m-2 decrease of total downward solar radiation over the global land surface during the period of 2003-2010. The results also suggested that the aerosol effect may be overwhelmed by clouds because of the stronger extinction and scattering ability of clouds. Applications of the iTem with solar radiation data and with or without considering the aerosol loadings shows that aerosol loading enhances the terrestrial productions [Gross Primary Production (GPP), Net Primary Production (NPP) and Net Ecosystem Production (NEP)] and carbon emissions through plant respiration (RA) in global terrestrial ecosystems over the

  3. Tropospheric ozone variability in the tropics from ENSO to MJO and shorter timescales

    NASA Astrophysics Data System (ADS)

    Ziemke, J. R.; Douglass, A. R.; Oman, L. D.; Strahan, S. E.; Duncan, B. N.

    2015-07-01

    Aura OMI and MLS measurements are combined to produce daily maps of tropospheric ozone beginning October 2004. We show that El Niño-Southern Oscillation (ENSO) related inter-annual change in tropospheric ozone in the tropics is small in relation to combined intra-seasonal/Madden-Julian Oscillation (MJO) and shorter timescale variability by a factor of ~ 3-10 (largest in the Atlantic). Outgoing longwave radiation (OLR), taken as a proxy for convection, suggests that convection is a dominant driver of large-scale variability of tropospheric ozone in the Pacific from inter-annual (e.g., ENSO) to weekly periods. We compare tropospheric ozone and OLR satellite observations with two simulations: (1) the Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) that uses observed sea surface temperatures and is otherwise free-running, and (2) the NASA Global Modeling Initiative (GMI) chemical transport model (CTM) that is driven by Modern Era Retrospective-Analysis for Research and Applications (MERRA) analyses. It is shown that the CTM-simulated ozone accurately matches measurements for timescales from ENSO to intra-seasonal/MJO and even 1-2-week periods. The CCM simulation reproduces ENSO variability but not shorter timescales. These analyses suggest that a model used to delineate temporal and/or spatial properties of tropospheric ozone and convection in the tropics must reproduce both ENSO and non-ENSO variability.

  4. Rapid increases in tropospheric ozone production and export from China: A view from AURA and TM5

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Neu, J. L.; Williams, J. E.; Bowman, K. W.; Worden, J. R.; Boersma, K. F.

    2015-12-01

    Eastern Asia has the fastest growing anthropogenic emissions in the world, possibly affecting both the pollution in the local troposphere as well as in the trans-Pacific region. Local measurements over Asia show that tropospheric ozone (O3) has increased by 1 to 3% per year since the start of the millennium. This increase is often invoked to explain positive tropospheric O3 trends observed in western US, but to date there is no unambiguous evidence showing that enhanced Asian pollution is responsible for these trends. In this research we use observations of tropospheric O3 from TES (Tropospheric Emission Spectrometer, onboard AURA), tropospheric NO2 measurements from OMI (Ozone Monitoring Instrument, onboard AURA) and lower stratospheric observations of O3 from MLS (Microwave Limb Sounder, onboard AURA) in combination with the TM5 CTM. Satellite-based studies focusing on tropospheric O3 and NO2 have the potential to close the gap left by previous studies on air quality since spaceborne data provide large-scale observational evidence that both O3 precursor concentrations and tropospheric O3 levels are rapidly changing over source receptor areas. We show the increased ability of TM5 to reproduce the 2005-2010 observed rapid rise in free tropospheric O3 of 7% over China from TES, once OMI NO2 measurements were implemented in TM5 to update NOX emissions. MLS observations on lower stratospheric O3 have the potential to improve the stratosphere-troposphere exchange (STE) estimate in TM5 which is mainly driven by ECMWF meteorological fields. Constraining the TM5 modelled trend of the STE contribution to the 3-9 km partial O3 column using MLS observations of stratospheric O3 lead to a better explanation of the sources of the free tropospheric O3 trends over China. Based on the OMI inferred TM5 updates in NOX emissions, the impact of Asian O3 and its precursors on the free troposphere (3-9 km) over the western US could be quantified. Large import from China offsets the

  5. Understanding the Tropospheric Ozone Response to Changes in the Stratospheric Circulation

    NASA Astrophysics Data System (ADS)

    Neu, J. L.; Kinnison, D. E.; Glanville, A. S.; Lee, M.; Walker, T. W.

    2015-12-01

    Chemistry-climate models robustly predict increases in the large-scale stratospheric circulation and stratosphere-troposphere exchange (STE) in response to increasing greenhouse gases. Our previous work has shown that current variability in the stratospheric circulation and stratosphere-to-troposphere ozone flux driven by a combination of El Niño /Southern Oscillation (ENSO) and the stratospheric Quasi-Biennial Oscillation (QBO) provides a "natural experiment" that may reduce uncertainties in predictions of the tropospheric ozone response to future changes in stratospheric transport. Using six years of measurements from the Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) onboard NASA's Aura satellite, we found that interannual variability in the stratospheric circulation of ~±40% leads to changes of ~±2% in northern midlatitude tropospheric ozone (equaling ~1/2 the total observed interannual variability). Here, we further explore the relationship between the stratospheric circulation and tropospheric ozone variability using two models: the Whole Atmosphere Chemistry-Climate Model (WACCM) and the GEOS-Chem chemistry-transport model (CTM). With the WACCM model, we further explore and untangle the roles of ENSO and the QBO in driving circulation changes and examine small but important differences in the response of the residual vertical velocity and the transport velocity (as measured by the water vapor tape recorder) to these cycles. We also diagnose large differences in the relationship between stratospheric and tropospheric ozone in the specified dynamics and free-running versions of WACCM. With the GEOS-Chem CTM, we use a 30-year simulation to examine the stability of our satellite-derived diagnostics over longer time periods and their sensitivity to changes in meteorology and emissions. We also apply our diagnostics to a 6-year joint 3Dvar assimilation of TES and MLS observations in GEOS-Chem and examine whether the assimilation

  6. Inter-Annual and Decadal Changes in Tropospheric and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, Jr. R.; Chandra, S.

    2011-01-01

    Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and studying their long-term changes. Using this technique, we have produced a 32-year (1979-2010) long record of tropospheric and stratospheric ozone from the combined Total Ozone Mapping Spectrometer (Toms) and OMI. The analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual changes of 30-40 Dobson Units (DU). Tropospheric ozone also indicates a QBO signal in the peak to peak changes varying from 2 to 7 DU. Decadal changes in global stratospheric ozone indicate a turnaround in ozone loss around mid 1990's with most of these changes occurring in the Northern Hemisphere from the subtropics to high latitudes. The trend results are generally consistent with the prediction of chemistry climate models which include the reduction of ozone destroying substances beginning in the late 1980's mandated by the Montreal Protocol.

  7. TOMS Tropical Tropospheric Ozone Data Sets at the University of Maryland Website

    NASA Technical Reports Server (NTRS)

    Kochhar, A. K.; Thompson, A. M.; Hudson, R. D.; Frolov, A. D.; Witte, J. C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Since 1997, shortly after the launch of the Earth-Probe TOMS (Total Ozone Mapping Spectrometer) satellite instrument, we have been processing data in near-real time to post maps of tropical tropospheric ozone at a website: metosrv2.umd.edu/-tropo. Daily, 3-day and 9-day averages of tropical tropospheric ozone column depth (TTO) are viewable from 10N to 10S. Data can be downloaded (running 9-day means) from 20N-30S. Pollution events are trackable along with dynamically-induced variations in tropospheric ozone column. TOMS smoke aerosol (toms.gsfc.nasa.gov) can be used to interpret biomass burning ozone, as for example, during the extreme ozone and smoke pollution period during the ENSO-related fires of August November 1997. During that time plumes of ozone and smoke were frequently decoupled and ozone from Indonesian fires and from Africa merged in one large feature by late October 1997. In addition to the Earth-Probe TOMS record, data as half-month averages and as daily 9-day means from the Nimbus 7 TOMS instrument are at the metosrv2.umd.edu/-tropo website. A guide to the website and examples of ozone time-series and maps will be shown.

  8. Influence of isentropic transport on seasonal ozone variations in the lower stratosphere and subtropical upper troposphere

    NASA Technical Reports Server (NTRS)

    Jing, P.; Cunnold, D. M.; Yang, E.-S.; Wang, H.-J.

    2005-01-01

    The isentropic cross-tropopause ozone transport has been estimated in both hemispheres in 1999 based on the potential vorticity mapping of Stratospheric Aerosol and Gas Experiment 11 ozone measurements and contour advection calculations using the NASA Goddard Space Flight Center Global and Modeling Assimilation Office analysis. The estimated net isentropic stratosphere-to-troposphere ozone flux is approx.118 +/- 61 x 10(exp9)kg/yr globally within the layer between 330 and 370 K in 1999; 60% of it is found in the Northern Hemisphere, and 40% is found in the Southern Hemisphere. The monthly average ozone fluxes are strongest in summer and weakest in winter in both hemispheres. The seasonal variations of ozone in the lower stratosphere (LS) and upper troposphere (UT) have been analyzed using ozonesonde observations from ozonesonde stations in the extratropics and subtropics, respectively. It is shown that observed ozone levels increase in the UT over subtropical ozonesonde stations and decrease in the LS over extratropical stations in late spring/early summer and that the ozone increases in the summertime subtropical UT are unlikely to be explained by photochemical ozone production and diabatic transport alone. We conclude that isentropic transport is a significant contributor to ozone levels in the subtropical upper troposphere, especially in summer.

  9. Determining relationships and mechanisms between tropospheric ozone column concentrations and tropical biomass burning in Thailand and its surrounding regions

    NASA Astrophysics Data System (ADS)

    Sonkaew, Thiranan; Macatangay, Ronald

    2015-06-01

    This study aims to determine the variability and trends of tropical biomass burning, tropospheric ozone levels from 2005-2012 in Thailand and the ozone transport from the surrounding regions. Intense biomass burning and tropospheric ozone in this area have a seasonal variability with the maximum generally occurring during the dry season. The northern part of Thailand was observed to have high tropospheric ozone during the dry peak season in April. Forward trajectory analysis determined that ozone sources due to biomass burning in the northern and western surrounding regions (Myanmar, Laos and India) enhance the tropospheric ozone column in northern Thailand. Seasonal variations were also seen for the middle and northeastern regions of Thailand. During August, most biomass burning occurs in Indonesia and Malaysia. However, forward trajectory analysis showed that the effect in the tropospheric ozone column level in the southern part of Thailand is minimal from these regions. Eight-year trends of tropospheric ozone column were also calculated for the different regions of Thailand. However, statistical analysis showed that these trends were not significant. The interannual variability of the tropospheric ozone column concentrations due to El Niño Southern Oscillation were also investigated. It was observed that the best correlation of the tropospheric ozone column with the Oceanic Niño Index (ONI) occured when ONI was advanced 3 months for the north, northeast and south regions of Thailand and 4 months for the middle region of Thailand.

  10. Monitoring the distribution of tropospheric ozone concentration over Pakistan by using OMI/MLS satellite observations

    NASA Astrophysics Data System (ADS)

    Noreen, Asma; Fahim Khokhar, Muhammad; Murtaza, Rabbia; Zeb, Naila

    2016-07-01

    Pakistan is a semi-arid, agricultural country located in Indian Sub-continent, Asia. Due to exponential population growth, poor control and regulatory measures and practices in industries, it is facing a major problem of air pollution. The concentration of greenhouse gases and aerosols are showing an increasing trend in general. One of these greenhouse gases is tropospheric ozone, one of the criteria pollutant, which has a radiative forcing (RF) of about 0.4 ± 0.2 Wm-2, contributing about 14% of the present total RF. Spatial distribution and temporal evolution of tropospheric ozone concentration over Pakistan during 2004 to 2014 was studied by using combined OMI/MLS product, which was derived by tropospheric ozone residual (TOR) method. Results showed an overall increase of 3.2 ± 2.2 DU in tropospheric ozone concentration over Pakistan since October 2004. The mean spatial distribution showed high concentrations of ozone in the Punjab and southern Sindh where there is high population densities along with rapid urbanization and enhanced anthropogenic activities. The seasonal variations were observed in the provinces of the country and TO3 VCDs were found to be high during summer while minimum during winter. The statistical analysis by using seasonal Mann Kendal test also showed strong positive trends over the four provinces as well as in major cities of Pakistan. These variations were driven by various factors such as seasonality in UV-B fluxes, seasonality in ozone precursor gases such as NOx and VOCs and agricultural fire activities in Pakistan. A strong correlation of 97% was found between fire events and tropospheric ozone concentration over the country. The results also depicted the influence of UV-B radiations on the tropospheric ozone concentration over different regions of Pakistan especially in Baluchistan and Sindh provinces.

  11. Tropospheric ozone trends at Mauna Loa Observatory tied to decadal climate variability

    NASA Astrophysics Data System (ADS)

    Lin, Meiyun; Horowitz, Larry W.; Oltmans, Samuel J.; Fiore, Arlene M.; Fan, Songmiao

    2014-02-01

    A potent greenhouse gas and biological irritant, tropospheric ozone is also the primary source of atmospheric hydroxyl radicals, which remove numerous hazardous trace gases from the atmosphere. Tropospheric ozone levels have increased in spring at remote sites in the mid-latitudes of the Northern Hemisphere over the past few decades; this increase has been attributed to a growth in Asian precursor emissions. In contrast, 40 years of continuous measurements at Mauna Loa Observatory in Hawaii reveal little change in tropospheric ozone levels during spring (March-April), but a rise in autumn (September-October). Here we examine the contribution of decadal shifts in atmospheric circulation patterns to decadal variability in tropospheric ozone levels at Mauna Loa using a suite of chemistry-climate model simulations. We show that the flow of ozone-rich air from Eurasia towards Hawaii during spring weakened in the 2000s as a result of La-Niña-like decadal cooling in the eastern equatorial Pacific Ocean. During autumn, in contrast, the flow of ozone-rich air from Eurasia to Hawaii strengthened in the mid-1990s onwards, coincident with the positive phase of the Pacific-North American pattern. We suggest that these shifts in atmospheric circulation patterns can reconcile observed trends in tropospheric ozone levels at Mauna Loa and the northern mid-latitudes in recent decades. We conclude that decadal variability in atmospheric circulation patterns needs to be considered when attributing observed changes in tropospheric ozone levels to human-induced trends in precursor emissions.

  12. Tropospheric temperature response to stratospheric ozone recovery in the 21st century

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; Fu, Q.

    2010-09-01

    Observations show a stabilization or a weak increase of the stratospheric ozone layer since the late 1990s. Recent coupled chemistry-climate model simulations predicted that the stratospheric ozone layer will likely return to pre-1980 levels in the middle of the 21st century, as a results of the decline of ozone depleting substances under the 1987 Montreal Protocol. Since the ozone layer is an important component in determining stratospheric and tropospheric-surface energy balance, the recovery of the ozone layer may have significant impact on tropospheric-surface climate. Here, using multi-model ensemble results from both the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC-AR4) models and coupled chemistry-climate models, we show that as ozone recovery is considered, the troposphere is warmed more than that without considering ozone recovery, suggesting an enhancement of tropospheric warming due to ozone recovery. It is found that the enhanced tropospheric warming is mostly significant in the upper troposphere, with a global mean magnitude of ~0.41 K for 2001-2050. We also find that relatively large enhanced warming occurs in the extratropics and polar regions in summer and autumn in both hemispheres while the enhanced warming is stronger in the Northern Hemisphere than in the Southern Hemisphere. Enhanced warming is also found at the surface. The strongest enhancement of surface warming is located in the Arctic in boreal winter. The global annual mean enhancement of surface warming is about 0.16 K for 2001-2050.

  13. Elevated Tropospheric Ozone Over the South Tropical Atlantic in January-February 1999: An Ozone Paradox Due to Interhemispheric Transport, Lightning, or Stratospheric Exchange?

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Doddridge, Bruce G.; Witte, Jacquelyn C.; Hudson, Robert D.; Luke, Winston T.; Johnson, James E.; Johnson, Bryan J.; Oltmans, Samuel J.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    On this first North American to southern African oceanographic cruise with ozonesonde launches (January and February 1999 on board the NOAA Research Vessel Ronald H Brown between Norfolk, VA, and Cape Town, South Africa) we found: (1) high ozone, CO, and aerosols off northern equatorial Africa from biomass burning, but even higher ozone concentrations off southern Africa which was not burning - an "ozone paradox"; (2) TOMS satellite evidence that south Atlantic elevated ozone in January-February 1999 was a regional feature similar in extent to the well-known September-October ozone maximum. Several mechanisms are considered to explain the "ozone paradox." Convection transporting air from the lower troposphere rich in ozone and/or ozone precursors to the upper troposphere through the ITCZ (intertropical Convergence Zone) may lead to cross-hemisphere transport of pollution. This is supported by trajectory linkage of lower-tropospheric ozone maxima with smoke seen by the TOMS satellite. Lightning-generated NO (nitric oxide) leading to ozone peaks of > 100 ppbv observed at 7-10 km altitude is another explanation. The TRMM (Tropical Rainfall Measuring Mission) Lightning Imaging Sounder shows many lightning flashes over southern Africa, which trajectories link to the high-ozone layers south of the ITCZ. The highest ozone peaks in the middle troposphere correspond to very low water vapor, which may point to photochemical destruction of ozone or subsidence from the upper troposphere which had interacted with stratospheric ozone.

  14. Signature of Cities in the Tropospheric Ozone Columns Obtained by the Empirically Corrected Tropospheric Ozone Residual Technique From TOMS/SBUV Measurements

    NASA Astrophysics Data System (ADS)

    Kar, J.; Fishman, J.; Creilson, J. K.; Richter, A.

    2009-05-01

    Tropospheric ozone is an important greenhouse gas in the upper troposphere and is also a precursor of OH radicals, thus strongly influencing tropospheric chemistry. At the surface, it is a pollutant and is the primary component of photochemical smog. As such it is one of the key trace gases that future satellite missions like the GEO CAPE (Geostationary Coastal and Air Pollution Events) mission will measure. It is thus important to carefully assess the capability of the existing satellite data products for possible air quality applications to set the stage for such missions. There is a long heritage of satellite based methods that subtract the stratospheric column from the total ozone column measured to estimate the tropospheric ozone residual (TOR). The TOR values obtained by the empirically corrected technique (Fishman et al., Atmos. Chem. Phys.,3, 893, 2003) from TOMS/SBUV measurements show regional level enhancements that correlate with population density in various parts of the globe. In this study, we show that distinct signatures of city-scale ozone pollution can also be detected in this data set. Case studies of enhanced TOR plumes observed in the downwind areas of several large polluted cities will be presented. Corresponding NO2 tropospheric columns from the SCIAMACHY instrument are consistent with these urban plumes. Such plumes, however, are not seen at all times. Our preliminary results indicate that detection of these plumes is correlated with local convection, which effectively transports boundary-layer pollution to higher altitudes where TOMS sensitivity to ozone is enhanced. These results may have important ramifications for future air quality studies using residual techniques.

  15. Radiative forcing perturbation due to observed increases in tropospheric ozone at Hohenpeissenberg

    NASA Technical Reports Server (NTRS)

    Wang, Wei-Chyung; Bojkov, Rumen D.; Zhuang, Yi-Cheng

    1994-01-01

    The effect on surface temperature due to changes in atmospheric O3 depends highly on the latitude where the change occurs. Previous sensitivity calculations indicate that ozone changes in the upper troposphere and lower stratosphere are more effective in causing surface temperature change (Wang et al., 1980). Long term ground-based observations show that tropospheric ozone, especially at the tropopause region, has been increasing at middle and high latitudes in the Northern Hemisphere (NATO, 1988; Quadrennial Ozone Symposium, 1992). These increases will enhance the greenhouse effect and increase the radiative forcing to the troposphere-surface system, which is opposite to the negative radiative forcing calculated from the observed stratospheric ozone depletion recently reported in WMO (1992). We used more than two thousands regularly measured ozonesondes providing reliable vertical O3 distribution at Hohenpeissenberg (47N; 11E) for the 1967-1990 to study the instantaneous solar and longwave radiative forcing the two decades 1971-1990 and compare the forcing with those caused by increasing CO2, CH4, N2O, and CFCs. Calculations are also made to compare the O3 radiative forcing between stratospheric depletion and tropospheric increase. Results indicate that the O3 changes will induce a positive radiative forcing dominated by tropospheric O3 increase and the magnitude of the forcing is comparable to that due to CO2 increases during the two decades. The significant implications of the tropospheric O3 increase to the global climate are discussed.

  16. Observation of ozone enhancement in the lower troposphere over East Asia from a space-borne ultraviolet spectrometer

    NASA Astrophysics Data System (ADS)

    Hayashida, S.; Liu, X.; Ono, A.; Yang, K.; Chance, K.

    2015-09-01

    We report observations from space using ultraviolet (UV) radiance for significant enhancement of ozone in the lower troposphere over central and eastern China (CEC). The recent retrieval products of the Ozone Monitoring Instrument (OMI) onboard the Earth Observing System (EOS) Aura satellite revealed the spatial and temporal variation of ozone distributions in multiple layers in the troposphere. We compared the OMI-derived ozone over Beijing with airborne measurements by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. The correlation between OMI and MOZAIC ozone in the lower troposphere was reasonable, which assured the reliability of OMI ozone retrievals in the lower troposphere under enhanced ozone conditions. The ozone enhancement was clearly observed over CEC, with Shandong Province as its center, and was most notable in June in any given year. Similar seasonal variations were observed throughout the 9-year OMI measurement period of 2005 to 2013. A considerable part of this ozone enhancement could be attributed to the emissions of ozone precursors from industrial activities and automobiles, and possibly from open crop residue burning (OCRB) after the winter wheat harvest. The ozone distribution presented in this study is also consistent with some model studies. The lower tropospheric ozone distribution is first shown from OMI retrieval in this study, and the results will be useful in clarifying any unknown factors that influence ozone distribution by comparison with model simulations.

  17. Trends of Rural Tropospheric Ozone at the Northwest of the Iberian Peninsula

    PubMed Central

    Saavedra, S.; Rodríguez, A.; Souto, J. A.; Casares, J. J.; Bermúdez, J. L.; Soto, B.

    2012-01-01

    Tropospheric ozone levels around urban and suburban areas at Europe and North America had increased during 80's–90's, until the application of NOx reduction strategies. However, as it was expected, this ozone depletion was not proportional to the emissions reduction. On the other hand, rural ozone levels show different trends, with peaks reduction and average increments; this different evolution could be explained by either emission changes or climate variability in a region. In this work, trends of tropospheric ozone episodes at rural sites in the northwest of the Iberian Peninsula were analyzed and compared to others observed in different regions of the Atlantic European coast. Special interest was focused on the air quality sites characterization, in order to guarantee their rural character in terms of air quality. Both episodic local meteorological and air quality measurements along five years were considered, in order to study possible meteorological influences in ozone levels, different to other European Atlantic regions. PMID:22649298

  18. Bimodal distribution of free tropospheric ozone over the tropical western Pacific revealed by airborne observations

    NASA Astrophysics Data System (ADS)

    Pan, L. L.; Honomichl, S. B.; Randel, W. J.; Apel, E. C.; Atlas, E. L.; Beaton, S. P.; Bresch, J. F.; Hornbrook, R.; Kinnison, D. E.; Lamarque, J.-F.; Saiz-Lopez, A.; Salawitch, R. J.; Weinheimer, A. J.

    2015-09-01

    A recent airborne field campaign over the remote western Pacific obtained the first intensive in situ ozone sampling over the warm pool region from oceanic surface to 15 km altitude (near 360 K potential temperature level). The new data set quantifies ozone in the tropical tropopause layer under significant influence of convective outflow. The analysis further reveals a bimodal distribution of free tropospheric ozone mixing ratio. A primary mode, narrowly distributed around 20 ppbv, dominates the troposphere from the surface to 15 km. A secondary mode, broadly distributed with a 60 ppbv modal value, is prominent between 3 and 8 km (320 K to 340 K potential temperature levels). The latter mode occurs as persistent layers of ozone-rich drier air and is characterized by relative humidity under 45%. Possible controlling mechanisms are discussed. These findings provide new insight into the physical interpretation of the "S"-shaped mean ozone profiles in the tropics.

  19. Tropospheric ozone and aerosol long-term trends over the Indo-Gangetic Plain (IGP), India

    NASA Astrophysics Data System (ADS)

    Lal, D. M.; Ghude, Sachin D.; Patil, S. D.; Kulkarni, Santosh H.; Jena, Chinmay; Tiwari, S.; Srivastava, Manoj K.

    2012-10-01

    We investigate, for the first time, long-term trends in tropospheric ozone and its association with the industrial growth in large part of India. A multifunction regression model has been used to estimate the trends in tropospheric ozone between 1979 and 1992 over the Indian region. Increasing trends in tropospheric ozone are observed over most of the regions of India. Recent year's (2005-2010) data also shows the similar features. It is quite consistent with the observed trends in coal (9.2%/year) and petroleum (8.3%/year) consumption, and NOx and CO emissions in India during the study period. The regressed Tropospheric Ozone Residual (TOR) pattern during monsoon season shows large trend over the entire Indo-Gangetic region and is largest, 6-7.2% per decade, over the northeastern Gangetic plain of India. Annually, trend of about 0.4 ± 0.25 (1σ) % per year has been seen over the northeastern Gangetic region. Similar positive trend in aerosol index (AI) (1.7 ± 1.2 (1σ) % per year) is also detected over this region. The quality of correlation between TOR and AI suggested that tropospheric ozone appeared to be influenced by the increased anthropogenic activities in this region.

  20. Four Summers of Ozone Profiles Over Beltsville, MD: A Study of Free-Tropospheric and Boundary Layer Ozone

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; Thompson, A. M.; Ryan, W. F.; Taubman, B. F.; Joseph, E.; Voemel, H.; Bojkov, B.; McQueen, J.

    2007-12-01

    A total of over 75 ozonesonde launches were made in Beltsville, MD during the summers of 2004 through 2007 as part of 4 different field campaigns; INTEX Ozonesonde Network Study 2004 (IONS-04, http://croc.gsfc.nasa.gov/intex/ions.html), Howard/NCAS ozonesondes for MDE (Maryland Department of the Environment) Pollution Episodes (http://www.physics1.howard.edu), and the Water Vapor Validation Experiment - Satellite/Sondes 2006 & 2007 (WAVES, http://ecotronics.com/lidar-misc/WAVES.htm). These profiles were used to characterize variability in sources of tropospheric ozone. On average, free-tropospheric ozone was composed of the following: 10% regional convection and lightning-derived NO, 25% stratospheric ozone, with the balance (~65%) a mixture of aged air of indeterminate origin and recently advected ozone. A separate analysis of local emission and boundary layer ozone was performed. The data from 2005 and 2006 includes both nighttime and daytime launches, permitting an investigation between planetary boundary layer processes and surface ozone. In nighttime profiles with above average column ozone in the residual layer, daily maximum 1 hr and 8 hr average surface ozone values were roughly 10 to 15 ppbv greater than days with below average column ozone in the residual layer. These results, as well as vertical profiles, were compared to the NOAA/EPA Operational Air Quality Model forecasts for Beltsville. The model showed a highly negative bias for maximum 1 hr ozone values, but only a slightly negative bias for maximum 8 hr ozone values on days with above average residual layer ozone.

  1. Tropospheric ozone in the Nisqually River Drainage, Mount Rainier National Park

    USGS Publications Warehouse

    Peterson, D.L.; Bowers, Darci

    1999-01-01

    We quantified the summertime distribution of tropospheric ozone in the topographically complex Nisqually River drainage of Mount Rainier National Park from 1994 to 1997. Passive ozone samplers were used along an elevational transect to measure weekly average ozone concentrations ranging from 570 m to 2040 m elevation. Weekly average ozone concentrations were positively correlated with elevation, with the highest concentrations consistently measured at the highest sampling site (Panorama Point). Weekly average ozone concentrations at Mount Rainier National Park are considerably higher than those in the Seattle-Tacoma metropolitan area to the west. The anthropogenic contribution to ozone within the Nisqually drainage was evaluated by comparing measurements at this location with measurements from a 'reference' site in the western Olympic Mountains. The comparison suggests there is a significant anthropogenic source of ozone reaching the Cascade Range via atmospheric transport from urban areas to the west. In addition. temporal (week to week) variation in ozone distribution is synchronous within the Nisqually drainage, which indicates that subregional patterns are detectable with weekly averages. The Nisqually drainage is likely the 'hot spot' for air pollution in Mount Rainier National Park. By using passive ozone samplers in this drainage in conjunction with a limited number of continuous analyzers, the park will have a robust monitoring approach for measuring tropospheric ozone over time and protecting vegetative and human health.

  2. Tropical Tropospheric Ozone from SHADOZ (Southern Hemisphere ADditional Ozonesondes) Network: A Project for Satellite Research, Process Studies, Education

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Schmidlin, Francis J.; Coetzee, G. J. R.; Hoegger, Bruno; Kirchhoff, V. W. J. H.; Ogawa, Toshihiro; Kawakami, Shuji; Posny, Francoise

    2002-01-01

    The first climatological overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropical and subtropics is based on ozone sounding data from 10 sites comprising the Southern Hemisphere Additional OZonesondes (SHADOZ) network. The period covered is 1998-2000. Observations were made over: Ascension Island; Nairobi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil. Campaign data were collected on a trans-Atlantic oceanographic cruise and during SAFARI-2000 in Zambia. The ozone data, with simultaneous temperature profiles to approx. 7 hPa and relative humidity to approx. 200 hPa, reside at: . SHADOZ ozone time-series and profiles give a perspective on tropical total, stratospheric and tropospheric ozone. Prominent features are highly variable tropospheric ozone and a zonal wave-one pattern in total (and tropospheric) column ozone. Total, stratospheric and tropospheric column ozone amounts peak between August and November and are lowest between March and May. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the Indian Ocean Dipole and convective mixing. Pollution transport from Africa and South America is a seasonal feature. Tropospheric ozone seasonality over the Atlantic Basin shows effects of regional subsidence and recirculation as well as biomass burning. Dynamical and chemical influences appear to be of comparable magnitude though model studies are needed to quantify this.

  3. First look at the NOAA Aircraft-based Tropospheric Ozone Climatology

    NASA Astrophysics Data System (ADS)

    Leonard, M.; Petropavlovskikh, I. V.; McClure-Begley, A.; Lin, M.; Tarasick, D.; Johnson, B. J.; Oltmans, S. J.

    2015-12-01

    The Global Greenhouse Gas Reference Network's aircraft program has operated since the 1990s as part of the NOAA Global Monitoring Division network to capture spatial and temporal variability in greenhouse tracers (i.e. CO2, CO, N2O, methane, SF6, halo- and hydro-carbons). Since 2005 the suite of airborne measurements also includes ozone, humidity and temperature profiling through the troposphere (up to 8 km). Light commercial aircraft are equipped with modified 2B Technology ozone monitors (Model 205DB), incorporate temperature and humidity probes, and include global positioning system instrumentation. The dataset was analyzed for tropospheric ozone variability at five continental US stations. As site locations within the Tropospheric Aircraft Ozone Measurement Program have flights only once (four times at one site) a month and begun a decade ago, this raises the question of whether this sampling frequency allows the derivation of an accurate vertical climatology of ozone values. We interpret the representativeness of the vertical and seasonal ozone distribution from aircraft measurements using multi-decadal hindcast simulations conducted with the GFDL AM3 chemistry-climate model. When available, climatology derived from co-located ozone-sonde data will be used for comparisons. The results of the comparisons are analyzed to establish altitude ranges in the troposphere where the aircraft climatology would be deemed to be the most representative. Aircraft-based climatologies are tested from two approaches: comparing the aircraft-based climatology to the daily sampled model and to the subset of model data with matching aircraft dates. Whenever the model and aircraft climatologies show significant seasonal differences, further information is gathered from a seasonal Gaussian distribution plot. We will report on the minimum frequency in flights that can provide adequate climatological representation of seasonal and vertical variability in tropospheric ozone.

  4. Distribution of tropospheric ozone at Brazzaville, Congo, determined from ozonesonde measurements

    NASA Technical Reports Server (NTRS)

    Cros, Bernard; Nganga, Dominique; Minga, Alexis; Fishman, Jack; Brackett, Vincent

    1992-01-01

    An analysis of 33 ozonesonde launches in Brazzaville, Congo (4 deg S, 15 deg E), between June 1990 and May 1991 is presented. The data indicate highest tropospheric amounts between June and early October, coincident with the dry season and with the presence of enhanced widespread biomass burning. The seasonal cycle of ozone derived from the ozonesonde measurements is in good agreement with the climatological seasonal cycle inferred from the use of satellite data amd both seasonal cycles peak in September. Averaged throughout the year, the integrated amount of ozone derived from the ozonesondes is 44 Dobson units (DU) and is 39 DU using the satellite data. Within the troposphere the highest partial pressures are generally found at pressure levels near 700 mbar (about 3 km). Using simultaneous ozonesonde data from Ascension Island (8 deg S, 15 deg W), examples are presented illustrating that differences in the troposphere are primarily responsible for the observed spatial gradients of total ozone observed by TOMS.

  5. Decline in the tropospheric abundance of halogen from halocarbons: Implications for stratospheric ozone depletion

    SciTech Connect

    Montzka, S.A.; Butler, J.H.; Myers, R.C.

    1996-05-31

    Analyses of air sampled from remote locations across the globe reveal that tropospheric chlorine attributable to anthropogenic halocarbons peaked near the beginning of 1994 and was decreasing at a rate of 25 {+-} parts per trillion per year by mid-1995. Although bromine from halons was still increasing in mid-1995, the summed abundance of these halogens in the troposphere is decreasing. To assess the effect of this trend on stratospheric ozone, estimates of the future stratospheric abundance of ozone-depleting gases were made for mid-latitude and polar regions on the basis of these tropospheric measurements. These results suggest that the amount of reactive chlorine and bromine will reach a maximum in the stratosphere between 1997 and 1999 and will decline thereafter if limits outlined in the adjusted and amended Montreal Protocol on Substances That Deplete the Ozone Layer are not exceeded in future years. 30 refs., 4 figs., 1 tab.

  6. The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation

    NASA Astrophysics Data System (ADS)

    Finney, D. L.; Doherty, R. M.; Wild, O.; Abraham, N. L.

    2016-06-01

    A lightning parametrisation based on upward cloud ice flux is implemented in a chemistry-climate model (CCM) for the first time. The UK Chemistry and Aerosols model is used to study the impact of these lightning nitric oxide (NO) emissions on ozone. Comparisons are then made between the new ice flux parametrisation and the commonly used, cloud-top height parametrisation. The ice flux approach improves the simulation of lightning and the temporal correlations with ozone sonde measurements in the middle and upper troposphere. Peak values of ozone in these regions are attributed to high lightning NO emissions. The ice flux approach reduces the overestimation of tropical lightning apparent in this CCM when using the cloud-top approach. This results in less NO emission in the tropical upper troposphere and more in the extratropics when using the ice flux scheme. In the tropical upper troposphere the reduction in ozone concentration is around 5-10 %. Surprisingly, there is only a small reduction in tropospheric ozone burden when using the ice flux approach. The greatest absolute change in ozone burden is found in the lower stratosphere, suggesting that much of the ozone produced in the upper troposphere is transported to higher altitudes. Major differences in the frequency distribution of flash rates for the two approaches are found. The cloud-top height scheme has lower maximum flash rates and more mid-range flash rates than the ice flux scheme. The initial Ox (odd oxygen species) production associated with the frequency distribution of continental lightning is analysed to show that higher flash rates are less efficient at producing Ox; low flash rates initially produce around 10 times more Ox per flash than high-end flash rates. We find that the newly implemented lightning scheme performs favourably compared to the cloud-top scheme with respect to simulation of lightning and tropospheric ozone. This alternative lightning scheme shows spatial and temporal differences in

  7. Distribution of tropospheric ozone in the tropics from satellite and ozonesonde measurements

    NASA Technical Reports Server (NTRS)

    Fishman, J.; Brackett, V. G.; Fakhruzzaman, K.

    1992-01-01

    Measurements from two independent satellite data sets have been used to derive the climatology of the integrated amount of ozone in the troposphere. These data have led to the finding that large amounts of ozone pollution are generated by anthropogenic activity originating from both the industrialized regions of the Northern Hemisphere and from the southern tropical regions of Africa. To verify the existence of this ozone anomaly over this region of the world, an ozonesonde capability has been established at Ascension Island, located downwind of the primary source region of this ozone pollution, which likely results from the photochemical oxidation of emissions emanating from the widespread burning of savanna. These first ozonesonde profiles suggest that much of the ozone generated over Africa during the 'burning season' (primarily July-October) reaches Ascension Island. These high levels of ozone in the lower troposphere become much lower by December. Elevated ozone concentrations in the middle troposphere are once again evident in February, which may be the result of biomass burning emissions being transported from western and northern Africa.

  8. Results obtained with the Tropospheric Ozone DIAL System Using a YAG Laser and Raman Cells

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.

    2012-12-01

    This poster will detail the findings of the ground based Differential Absorption Lidar (DIAL) system built and operated at the NASA Goddard Space Flight Center (Beltsville, MD 38.99° N, 76.84° W) in 2012. Current atmospheric satellites cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, NASA has funded the ground based Tropospheric Ozone Lidar Network (TOLNET) which currently consists of five stations across the US. The Goddard instrument is based on the Differential Absorption Lidar (DIAL) technique, and has initially transmitted two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm, and the DIAL technique exploits this difference between the two returned signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman Cells, filled with high pressure Hydrogen and Deuterium. Stimulated Raman Scattering within the focus shifts the pump wavelength, and the first Stokes shift in each cell produces the required wavelengths. With the knowledge of the ozone absorption coefficient at these two wavelengths, the vertical number density can then be derived. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make long term ozone profile measurements in the Washington, DC - Baltimore area.

  9. Tropical and Midlatitude Tropospheric Column Ozone Response to ENSO in GEOS-5 Assimilation of OMI and MLS Ozone Data

    NASA Astrophysics Data System (ADS)

    Olsen, M. A.; Wargan, K.; Pawson, S.

    2015-12-01

    Nine years of ozone observations from the Ozone Monitoring Instrument and Microwave Limb Sounder have been assimilated into the Goddard Earth Observing System Version 5 data assimilation system. We investigate the magnitude and spatial distribution of the influence by the El Niño Southern Oscillation (ENSO) on tropospheric column ozone (TCO) in the tropics through the middle latitudes. The tropospheric response in the tropics agrees well with previous studies. A newly identified two-lobed response symmetric about the Equator in the western Pacific/Indonesian region is consistent with the large-scale vertical transport. The ozone response is weaker in the middle latitudes, but significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations. The associated vertical transport is consistent with the sign of the sensitivity. ENSO related changes to the mean depth of the tropospheric column have little impact on the TCO response in the tropics but can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the nine-year assimilation are representative of the longer-term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes. In addition, these results are valuable as a process-oriented assessment of the tropospheric response in model simulations.

  10. Photochemistry and transport of tropospheric ozone and its precursors in urban and remote environments

    NASA Astrophysics Data System (ADS)

    Anderson, Daniel Craig

    Tropospheric ozone (O3) adversely affects human health, reduces crop yields, and contributes to climate forcing. To limit these effects, the processes controlling O3 abundance as well as that of its precursor molecules must be fully characterized. Here, I examine three facets of O 3 production, both in heavily polluted and remote environments. First, using in situ observations from the DISCOVER-AQ field campaign in the Baltimore/Washington region, I evaluate the emissions of the O 3 precursors CO and NOx (NOx = NO + NO2) in the National Emissions Inventory (NEI). I find that CO/NOx emissions ratios derived from observations are 21% higher than those predicted by the NEI. Comparisons to output from the CMAQ model suggest that CO in the NEI is accurate within 15 +/- 11%, while NOx emissions are overestimated by 51-70%, likely due to errors in mobile sources. These results imply that ambient ozone concentrations will respond more efficiently to NOx controls than current models suggest. I then investigate the source of high O3 and low H2O structures in the Tropical Western Pacific (TWP). A combination of in situ observations, satellite data, and models show that the high O3 results from photochemical production in biomass burning plumes from fires in tropical Southeast Asia and Central Africa; the low relative humidity results from large-scale descent in the tropics. Because these structures have frequently been attributed to mid-latitude pollution, biomass burning in the tropics likely contributes more to the radiative forcing of climate than previously believed. Finally, I evaluate the processes controlling formaldehyde (HCHO) in the TWP. Convective transport of near surface HCHO leads to a 33% increase in upper tropospheric HCHO mixing ratios; convection also likely increases upper tropospheric CH 3OOH to ~230 pptv, enough to maintain background HCHO at ~75 pptv. The long-range transport of polluted air, with NO four times the convectively controlled background

  11. Impacts of climate change and variability on tropospheric ozone and its precursors.

    PubMed

    Stevenson, David; Doherty, Ruth; Sanderson, Michael; Johnson, Colin; Collins, Bill; Derwent, Dick

    2005-01-01

    Two coupled climate-chemistry model experiments for the period 1990-2030 were conducted: one with a fixed climate and the other with a varying climate forced by the is92a scenario. By comparing results from these experiments we have attempted to identify changes and variations in physical climate that may have important influences upon tropospheric chemical composition. Climate variables considered include: temperature, humidity, convective mass fluxes, precipitation, and the large-scale circulation. Increases in humidity, directly related to increases in temperature, exert a major influence on the budgets of ozone and the hydroxyl radical: decreasing 03 and increasing OH. Warming enhances decomposition of PAN, releasing NOx, and increases the rate of methane oxidation. Surface warming enhances vegetation emissions of isoprene, an important ozone precursor. In the changed climate, tropical convection generally reduces, but penetrates to higher levels. Over northern continents, convection tends to increase. These changes in convection affect both vertical mixing and lightning NOx emissions. We find no global trend in lightning emissions, but significant changes in its distribution. Changes in precipitation and the large-scale circulation are less important for composition, at least in these experiments. Higher levels of the oxidants OH and H202 lead to increases in aerosol formation and concentrations. These results indicate that climate-chemistry feedbacks are dominantly negative (less 03, a shorter CH4 lifetime, and more aerosol). The major mode of inter-annual variability in the is92a climate experiment is ENSO. This strongly modulates isoprene emissions from vegetation via tropical land surface temperatures. ENSO is also clearly the dominant source of variability in tropical column ozone, mainly through changes in the distribution of convection. The magnitude of inter-annual variability in ozone is comparable to the changes brought about by emissions and climate

  12. Tropical Tropospheric Ozone: A Multi-Satellite View From TOMS and Other Instruments

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Hudson, Robert D.; Guo, Hua; Witte, Jacquelyn C.; Kucsera, Tom L.; Seybold, Matthew G.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    New tropospheric ozone and aerosol products from the TOMS (Total Ozone Mapping Spectrometer) satellite instrument can resolve episodic pollution events in the tropics and interannual and seasonal variability. Modified-residual (MR) Nimbus 7 tropical tropospheric ozone (TTO), two maps/month (1979-1992, 1-deg latitude by 2-deg longitude) within the region in which total ozone displays a tropical wave-one pattern (maximum 20S to 20N), are available in digital form at http://metosrv2.umd.edu/tropo. Also available are preliminary 1996-1999 MR-TTO maps based on real-time Earth-Probe (EP)/TOMS observations. Examples of applications are given.

  13. Insights into Tropical Tropospheric Ozone from the 1998-2000 SHADOZ (Southern Hemisphere Additional Ozonesondes) Data Record

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Schmidlin, Francis J.; Volker, W.; Kirchhoff, J. H.; Posny, Franaoise; Gert, J.; Coetzee, R.; Hoegger, Bruno; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    We describe the first overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropics based on a three year, ten site record of ozone soundings from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. Observations covering 1998-2000 were made over Ascension Island; Nairobi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil. The ozone data, with simultaneous temperature profiles to approximately 7 hPa and relative humidity to approximately 200 hPa, are at an archive: http://code9l6. gsfc.nasa.gov/Data_services/shadoz. Prominent features are highly variable tropospheric ozone, a zonal wave-one pattern in total (and tropospheric) column ozone, and signatures of the Quasi-Biennial Oscillation (QBO) in stratospheric ozone. Total, stratospheric and tropospheric column ozone amounts usually peak between August and November and are lowest in the first half of the year. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the waning 1997-1998 Indian Ocean Dipole and ENSO (El Nino / Southern Oscillation), seasonal convection and pollution transport from Africa. Tropospheric ozone over the Atlantic Basin reflects regional subsidence and recirculation as well as pollution ozone from biomass burning.

  14. The derivation of tropospheric column ozone using the TOR approach and mapping technique

    NASA Astrophysics Data System (ADS)

    Yang, Qing

    2007-12-01

    Tropospheric ozone columns (TCOs) derived from differences between the Dutch-Finnish Aura Ozone Monitoring Instrument (OMI) measurements of the total atmospheric ozone column and the Aura Microwave Limb Sounder (MLS) measurements of stratospheric ozone columns are discussed. Because the measurements by these two instruments are not spatially coincident, interpolation techniques, with emphasis on mapping the stratospheric columns in space and time using the relationships between lower stratospheric ozone and potential vorticity (PV) and geopotential heights (Z), are evaluated at mid-latitudes. It is shown that this PV mapping procedure produces somewhat better agreement in comparisons with ozonesonde measurements, particularly in winter, than does simple linear interpolation of the MLS stratospheric columns or the use of typical coincidence criteria at mid-latitudes. The OMI/MLS derived tropospheric columns are calculated to be 4 Dobson units (DU) smaller than the sonde measured columns at mid-latitudes. This mean difference is consistent with the MLS (version 1.5) stratospheric ozone columns being high relative to Stratospheric Aerosol and Gas Experiment (SAGE II) columns by 3 DU. Standard deviations between the derived tropospheric columns and those measured by ozonesondes are 9 DU (30%) annually but they are just 6 DU (15%) in summer. Uncertainties in the interpolated MLS stratospheric columns are likely to be the primary cause of these standard deviations. An important advantage of the PV mapping approach is that it works well when MLS data are missing (e.g., when an orbit of measurements is missing). In the comparisons against ozonesonde measurements, it provides up to twice as many comparisons compared to the other techniques. The OMI/MLS derived tropospheric ozone columns have been compared with corresponding columns based on the Tropospheric Emission Spectrometer (TES) measurements, and Regional chEmical trAnsport Model (REAM) simulations. The variability of

  15. The Ozone Budget in the Upper Troposphere from Global Modeling Initiative (GMI)Simulations

    NASA Technical Reports Server (NTRS)

    Rodriquez, J.; Duncan, Bryan N.; Logan, Jennifer A.

    2006-01-01

    Ozone concentrations in the upper troposphere are influenced by in-situ production, long-range tropospheric transport, and influx of stratospheric ozone, as well as by photochemical removal. Since ozone is an important greenhouse gas in this region, it is particularly important to understand how it will respond to changes in anthropogenic emissions and changes in stratospheric ozone fluxes.. This response will be determined by the relative balance of the different production, loss and transport processes. Ozone concentrations calculated by models will differ depending on the adopted meteorological fields, their chemical scheme, anthropogenic emissions, and treatment of the stratospheric influx. We performed simulations using the chemical-transport model from the Global Modeling Initiative (GMI) with meteorological fields from (It)h e NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM), (2) the atmospheric GCM from NASA's Global Modeling and Assimilation Office(GMAO), and (3) assimilated winds from GMAO . These simulations adopt the same chemical mechanism and emissions, and adopt the Synthetic Ozone (SYNOZ) approach for treating the influx of stratospheric ozone -. In addition, we also performed simulations for a coupled troposphere-stratosphere model with a subset of the same winds. Simulations were done for both 4degx5deg and 2degx2.5deg resolution. Model results are being tested through comparison with a suite of atmospheric observations. In this presentation, we diagnose the ozone budget in the upper troposphere utilizing the suite of GMI simulations, to address the sensitivity of this budget to: a) the different meteorological fields used; b) the adoption of the SYNOZ boundary condition versus inclusion of a full stratosphere; c) model horizontal resolution. Model results are compared to observations to determine biases in particular simulations; by examining these comparisons in conjunction with the derived budgets, we may pinpoint

  16. Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

    PubMed

    Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

    2011-06-01

    Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. PMID:21477906

  17. Free tropospheric ozone production following entrainment of urban plumes into deep convection

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.; Thompson, Anne M.; Scala, John R.; Tao, Wei-Kuo; Dickerson, Russell R.; Simpson, Joanne

    1992-01-01

    It is shown that rapid vertical transport of air from urban plumes through deep convective clouds can cause substantial enhancement of the rate of O3 production in the free troposphere. Simulation of convective redistribution and subsequent photochemistry of an urban plume from Oklahoma City during the 1985 PRESTORM campaign shows enhancement of O3 production in the free tropospheric cloud outflow layer by a factor of almost 4. In contrast, simulation of convective transport of an urban plume from Manaus, Brazil, into a prestine free troposphere during GTE/ABLE 2B (1987), followed by a photochemical simulation, showed enhancement of O3 production by a factor of 35. The reasons for the different enhancements are (1) intensity of cloud vertical motion; (2) initial boundary layer O3 precursor concentrations; and (3) initial amount of background free tropospheric NO(x). Convective transport of ozone precursors to the middle and upper troposphere allows the resulting O3 to spread over large geographic regions, rather than being confined to the lower troposphere where loss processes are much more rapid. Conversely, as air with lower NO descends and replaces more polluted air, there is greater O3 production efficiency per molecule of NO in the boundary layer following convective transport. As a result, over 30 percent more ozone could be produced in the entire tropospheric column in the first 24 hours following convective transport of urban plumes.

  18. The role of isoprene oxidation in the tropospheric ozone budget in the tropics

    NASA Technical Reports Server (NTRS)

    Brewer, D. A.; Levine, J. S.

    1985-01-01

    A comprehensive chemical mechanism for the oxidation of isoprene (a hydrocarbon, C5H8 emitted primarily by vegetation) by OH and O3 in the troposphere was developed and incorporated into a one-dimensional steady-state photochemical model of the troposphere. Flux boundary conditions for NOx (NO + NO2), HNO3, O3, and CO were used to investigate the changes produced in the tropospheric concentrations and integrated column of ozone from including isoprene chemistry in the model. Two calculations were performed at 15 deg N latitude for annual conditions using identical flux boundary conditions for NOx, HNO3, O3, and CO; in one calculation, the chemistry describing isoprene oxidation was included while in the other it was not. Both sets of calculations included reactions describing the chemistry of anthropogenic nonmethane hydrocarbons. The calculations showed decreases in concentrations of ozone throughout the troposphere when isoprene chemistry was included. Concentrations of NOx and HNO3 increased in the lower troposphere and decreased in the upper troposphere while concentrations of CO and PAN increased throughout the troposphere when isoprene chemistry was included. Implications of this study to the budgets of these species in the tropics is discussed.

  19. Lidar-derived Correlations Between Lower-tropospheric Column and Surface Ozone: Implications for Satellite Observations

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Alvarez, R. J. _II, II; Kirgis, G.; Choukulkar, A.; Brewer, A.; Banta, R. M.; Weickmann, A. M.; Sandberg, S.; Olson, E.

    2015-12-01

    One of the data products that will be provided by the TEMPO satellite mission is 0-2 km ozone column concentration. To make inferences about surface air quality from this data product, the relationship between lower-tropospheric column and surface ozone concentrations and their diurnal, seasonal, and spatial variations have to be well understood. To characterize these relationships, we have used ozone profile observations obtained with NOAA's truck-based, scanning TOPAZ ozone lidar from several recent field campaigns including Discover-AQ Houston and Colorado, the Uintah Basin Wintertime Ozone Study (UBWOS), and the Las Vegas Ozone Study (LVOS). The TOPAZ lidar is ideally suited for this kind of study because it provides ozone profiles from about 15 m above ground level (AGL) up to 3 km AGL at high spatial and temporal resolution. We have used the lidar observations closest to the ground as a proxy for surface ozone and compared them to the 0-2 km AGL average column ozone concentrations measured with the lidar. Results from the Discover-AQ Colorado campaign show that in the afternoon, when the boundary layer (BL) was deep and well mixed, ozone column and surface concentrations agreed quite well. However, during the morning hours, ozone column concentrations were significantly higher than those at the surface, because ozone was depleted in a shallow surface layer due to titration and deposition, whereas ozone levels in the residual layer aloft remained moderately high. The analysis of column and surface ozone correlations using ozone lidar observations from the Discover-AQ Houston, UBWOS and LVOS campaigns is currently underway. The results from these studies will provide additional insights into the relationship between column and surface ozone, in particular their variation as a function of measurement location and season, and their dependence on BL processes such as mixed layer height evolution, land-sea breeze circulation, and terrain-induced flows.

  20. Ozone: Does It Affect Me?

    ERIC Educational Resources Information Center

    Wilson, Karla G.

    This curriculum unit on the ozone is intended for high school students and contains sections on environmental science and chemistry. It has been structured according to a learning cycle model and contains numerous activities, some of which are in a cooperative learning format. Skills emphasized include laboratory procedures, experimental design,…

  1. First Directly Retrieved Global Distribution of Tropospheric Column Ozone from GOME: Comparison with the GEOS-CHEM Model

    NASA Technical Reports Server (NTRS)

    Liu, Xiong; Chance, Kelly; Sioris, Christopher E.; Kurosu, Thomas P.; Spurr, Robert J. D.; Martin, Randall V.; Fu, Tzung-May; Logan, Jennifer A.; Jacob, Daniel J.; Palmer, Paul I.; Newchurch, Michael J.; Megretskaia, Inna A.; Chatfield, Robert B.

    2006-01-01

    We present the first directly retrieved global distribution of tropospheric column ozone from Global Ozone Monitoring Experiment (GOME) ultraviolet measurements during December 1996 to November 1997. The retrievals clearly show signals due to convection, biomass burning, stratospheric influence, pollution, and transport. They are capable of capturing the spatiotemporal evolution of tropospheric column ozone in response to regional or short time-scale events such as the 1997-1998 El Nino event and a 10-20 DU change within a few days. The global distribution of tropospheric column ozone displays the well-known wave-1 pattern in the tropics, nearly zonal bands of enhanced tropospheric column ozone of 36-48 DU at 20degS-30degS during the austral spring and at 25degN-45degN during the boreal spring and summer, low tropospheric column ozone of <30 DU uniformly distributed south of 35 S during all seasons, and relatively high tropospheric column ozone of >33 DU at some northern high-latitudes during the spring. Simulation from a chemical transport model corroborates most of the above structures, with small biases of <+/-5 DU and consistent seasonal cycles in most regions, especially in the southern hemisphere. However, significant positive biases of 5-20 DU occur in some northern tropical and subtropical regions such as the Middle East during summer. Comparison of GOME with monthly-averaged Measurement of Ozone and Water Vapor by Airbus in-service Aircraft (MOZAIC) tropospheric column ozone for these regions usually shows good consistency within 1 a standard deviations and retrieval uncertainties. Some biases can be accounted for by inadequate sensitivity to lower tropospheric ozone, the different spatiotemporal sampling and the spatiotemporal variations in tropospheric column ozone.

  2. Biomonitoring of tropospheric ozone phytotoxicity in rural Catalonia

    NASA Astrophysics Data System (ADS)

    Ribas, Angela; Peñuelas, Josep

    The ozone (O 3) phytotoxicity in rural areas of Catalonia (NE Spain) and the biomonitoring capacity of Bel-W3 tobacco ( Nicotiana tabacum) cultivars were assessed by determining the percentage of leaf area injured by ozone in plants of this cultivar exposed from spring to autumn since 1995-1999. The study was conducted simultaneously on nine field sites where ground level ozone concentrations and meteorological parameters were continuously monitored. Geographical, seasonal and annual variations of ozone damage rate and their links with meteorological conditions were studied. Ozone concentrations and leaf damage increased at the end of spring and the beginning of summer. Coastal sites generally presented higher O 3 concentrations than inland and mountain sites. These mountain sites were the most sensitive ones to ozone toxicity. The ozone concentrations correlated well with ozone injury. However, at this local scale the ozone levels did not fully account for all the observed injury (only 11%). The response of tobacco plants to ozone concentrations and therefore its biomonitoring capacity depended also on different environmental conditions, mainly those linked to stomatal behaviour such as vapour pressure deficit. The categorization of leaf damage in 10% intervals and its averaging throughout the whole study period and the whole region, strongly improved (99% of variance accounted) the relationship with ozone concentrations expressed as AOT20 (accumulated over a cut-off of 20 ppb v). N. tabacum cultivar Bel-W3 is thus a very good biomonitor of ozone concentrations in the long term at the regional scale. Taking into account the phytotoxical response of this sensitive tobacco cultivar, we propose the 1.28 ppm v h biweekly AOT40 (with a solar radiation threshold of 50 W m -2) as a damage threshold level for sensitive species.

  3. Free-troposphere ozone and carbon monoxide over the North Atlantic for 2001-2011

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Wu, S.; Weise, M. F.; Honrath, R.; Owen, R. C.; Helmig, D.; Kramer, L.; Martin, M. Val; Li, Q.

    2013-12-01

    In situ measurements of carbon monoxide (CO) and ozone (O3) at the Pico Mountain Observatory (PMO) located in the Azores, Portugal, are analyzed together with results from an atmospheric chemical transport model (GEOS-Chem) and satellite remote sensing data (AIRS (Atmospheric Infrared Sounder) for CO, and TES (Tropospheric Emission Spectrometer) for O3) to examine the evolution of free-troposphere CO and O3 over the North Atlantic for 2001-2011. GEOS-Chem captured the seasonal cycles for CO and O3 well but significantly underestimated the mixing ratios of CO, particularly in spring. Statistically significant (using a significance level of 0.05) decreasing trends were found for both CO and O3 based on harmonic regression analysis of the measurement data. The best estimates of the possible trends for CO and O3 measurements are -0.31 ± 0.30 (2-σ) ppbv yr-1 and -0.21 ± 0.11 (2-σ) ppbv yr-1, respectively. Similar decreasing trends for both species were obtained with GEOS-Chem simulation results. The most important factor contributing to the decreases in CO and O3 at PMO over the past decade is the decline in anthropogenic emissions from North America, which more than compensate for the impacts from increasing Asian emissions. It is likely that climate change in the past decade has also affected the intercontinental transport of O3.

  4. Insights into Tropospheric Ozone from the INTEX Ozonesonde Network Study (IONS)

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, J. C.; Kucsera, T. L.; Merrill, J. T.; Morris, G.; Newchurch, M. J.; Oltmans, S. J.; Schmidlin, F. J.; Tarasick, D. J.

    2004-01-01

    Ozone profile data from soundings integrate models, aircraft and other ground-based measurements for better interpretation of atmospheric chemistry and dynamics. A well-designed network of ozonesonde stations, with consistent sampling, can answer questions not possible with short campaigns or current satellite technology. The SHADOZ (Southern Hemisphere Additional Ozonesondes) project, for example, has led to these findings about tropical ozone: definition of the zonal tropospheric wave-one pattern in equatorial ozone, characterization of the "Atlantic ozone paradox" and establishment of a link between tropical Atlantic and Indian Ocean pollution. Building on the SHADOZ concept, a short-term ozone network was formed in July-August 2004 to coordinate ozonesonde launches during the ICARTT/INTEX/NEAQS (International Consortium on Atmospheric Research on Transport and Transformation)/Intercontinental Transport Experiment/New England Air Quality Study. In IONS (INTEX Ozonesonde Network Study), more than 250 soundings, with daily frequency at half the sites, were launched from eleven North American stations and an oceanographic ship in the Gulf of Maine. Although the goal was to examine pollution influences under stable high-pressure systems and transport associated with "warm conveyor belt" flows, the INTEX study region was dominated by a series of weak frontal system that mixed aged pollution with stratospheric ozone in the middle troposphere. Deconvoluting ozone sources provides new insights into ozone in the transition between mid-latitude and polar air.

  5. Detection of a tropospheric ozone anomaly using a newly developed ozone retrieval algorithm for an up-looking infrared interferometer

    NASA Astrophysics Data System (ADS)

    Lightner, K. J.; McMillan, W. W.; McCann, K. J.; Hoff, R. M.; Newchurch, M. J.; Hintsa, E. J.; Barnet, C. D.

    2009-03-01

    On 2 June 2003, the Baltimore Bomem Atmospheric Emitted Radiance Interferometer (BBAERI) recorded an infrared spectral time series indicating the presence of a tropospheric ozone anomaly. The measurements were collected during an Atmospheric Infrared Sounder (AIRS) validation campaign called the 2003 AIRS BBAERI Ocean Validation Experiment (ABOVE03) conducted at the United States Coast Guard Chesapeake Light station located 14 miles due east of Virginia Beach, Virginia (36.91°N, 75.71°W). Ozone retrievals were performed with the Kurt Lightner Ozone BBAERI Retrieval (KLOBBER) algorithm, which retrieves tropospheric column ozone, surface to 300 mbar, from zenith-viewing atmospheric thermal emission spectra. KLOBBER is modeled after the AIRS retrieval algorithm consisting of a synthetic statistical regression followed by a physical retrieval. The physical retrieval is implemented using the k-Compressed Atmospheric Radiative Transfer Algorithm (kCARTA) to compute spectra. The time series of retrieved integrated ozone column on 2 June 2003 displays spikes of about 10 Dobson units, well above the error of the KLOBBER algorithm. Using instrumentation at Chesapeake Light, satellite imaging, trace gas retrievals from satellites, and Potential Vorticity (PV) computations, it was determined that these sudden increases in column ozone likely were caused by a combination of midtropospheric biomass burning products from forest fires in Siberia, Russia, and stratospheric intrusion by a tropopause fold occurring over central Canada and the midwestern United States.

  6. High-resolution tropospheric ozone fields for INTEX and ARCTAS from IONS ozonesondes

    NASA Astrophysics Data System (ADS)

    Tarasick, D. W.; Jin, J. J.; Fioletov, V. E.; Liu, G.; Thompson, A. M.; Oltmans, S. J.; Liu, J.; Sioris, C. E.; Liu, X.; Cooper, O. R.; Dann, T.; Thouret, V.

    2010-10-01

    The IONS-04, IONS-06, and ARC-IONS ozone sounding campaigns over North America in 2004, 2006, and 2008 obtained approximately 1400 profiles, in five series of coordinated and closely spaced (typically daily) launches. Although this coverage is unprecedented, it is still somewhat sparse in its geographical spacing. Here we use forward and back trajectory calculations for each sounding to map ozone measurements to a number of other locations and so to fill in the spatial domain. This is possible because the lifetime of ozone in the troposphere is of the order of weeks. The trajectory-mapped ozone values show reasonable agreement, where they overlap, to the actual soundings, and the patterns produced separately by forward and backward trajectory calculations are similar. Comparisons with MOZAIC profiles and surface station data show generally good agreement. A variable-length smoothing algorithm is used to fill data gaps: for each point on the map, the smoothing radius is such that a minimum of 10 data points are included in the average. The total tropospheric ozone column maps calculated by integrating the smoothed fields agree well with similar maps derived from TOMS and OMI/MLS measurements. The resulting three-dimensional picture of the tropospheric ozone field for the INTEX and ARCTAS periods facilitates visualization and comparison of different years and seasons and will be useful to other researchers.

  7. Impact of Flow-Dependent Error Correlations and Tropospheric Chemistry on Assimilated Ozone

    NASA Technical Reports Server (NTRS)

    Wargan, K.; Stajner, I.; Hayashi, H.; Pawson, S.; Jones, D. B. A.

    2003-01-01

    The presentation compares different versions of a global three-dimensional ozone data assimilation system developed at NASA's Data Assimilation Office. The Solar Backscatter Ultraviolet/2 (SBUV/2) total and partial ozone column retrievals are the sole data assimilated in all of the experiments presented. We study the impact of changing the forecast error covariance model from a version assuming static correlations with a one that captures a short-term Lagrangian evolution of those correlations. This is further combined with a study of the impact of neglecting the tropospheric ozone production, loss and dry deposition rates, which are obtained from the Harvard GEOS-CHEM model. We compare statistical characteristics of the assimilated data and the results of validation against independent observations, obtained from WMO balloon-borne sondes and the Polar Ozone and Aerosol Measurement (POAM) III instrument. Experiments show that allowing forecast error correlations to evolve with the flow results in positive impact on assimilated ozone within the regions where data were not assimilated, particularly at high latitudes in both hemispheres. On the other hand, the main sensitivity to tropospheric chemistry is in the Tropics and sub-Tropics. The best agreement between the assimilated ozone and the in-situ sonde data is in the experiment using both flow-dependent error covariances and tropospheric chemistry.

  8. Global atmospheric sampling program - Prospects for establishing a tropospheric ozone budget from commercial aircraft data

    NASA Technical Reports Server (NTRS)

    Falconer, P. D.

    1978-01-01

    A preliminary analysis of zonally averaged, ozone concentration data obtained from commercial (GASP) aircraft between the equator and 60 deg North indicates that ozone in the upper troposphere exhibits a primary maximum during the spring, and, in middle latitudes, a secondary maximum in the summer of both 1975 and 1976. A late-fall/early-winter minimum also appears and seems consistent with previous upper air measurements. The April ozone maximum has been well documented and appears at the time when the stratospheric ozone content is greatest and cyclogenetic activity is most vigorous. However, the secondary maximum in June has not been widely observed or quoted as a unique feature. It is hypothesized that the rapid ascent of the tropopause between midspring and summer could account for the incorporation of ozone-rich, stratospheric air into the upper troposphere with a subsequent dilution during the following months. This may explain certain aspects of the annual ozone cycle in the lower troposphere which occasionally exhibit a bimodal distribution during the warm season.

  9. Isentropic scaling analysis of ozone in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Cho, John Y. N.; Thouret, ValéRie; Newell, Reginald E.; Marenco, Alain

    2001-05-01

    We examine ozone concentrations recorded by 7630 commercial flights from August 1994 to December 1997 for spatial scaling properties. The large amount of data allows an approximately isentropic analysis of ozone variability in the upper troposphere and lower stratosphere. Since ozone is a good passive tracer at cruise altitudes, the results provide a strong diagnostic for scalar advection theories and models. Calculations of structure functions and increment probability distribution functions show that ozone variability scales anomalously from ˜2 to ˜2000 km, although not continuously in this interval. We find no evidence for the simple scaling predicted for smooth advection/diffusion, even at the large scales. At mesoscales the upper tropospheric ozone field is rougher and more intermittent than in the lower stratosphere. Within the troposphere the equatorial ozone field is rougher than at higher latitudes, and the intermittency decreases with increasing latitude. In the stratosphere the intermittency and roughness are greater at high latitudes and over land than at midlatitudes and over the ocean.

  10. Reactive Nitrogen, Ozone and Ozone Production in the Arctic Troposphere and the Impact of Stratosphere-Troposphere Exchange

    NASA Technical Reports Server (NTRS)

    Liang, Q.; Rodriquez, J. M.; Douglass, A. R.; Crawford, J. H.; Apel, E.; Bian, H.; Blake, D. R.; Brune, W.; Chin, M.; Colarco, P. R.; daSilva, A.; Diskin, G. S.; Duncan, B. N.; Huey, L. C.; Knapp, D. J.; Montzka, D. D.; Nielsen, J. E.; Olson, J. R.; Pawson, S.; Weinheimer, A. J.

    2011-01-01

    We analyze the aircraft observations obtained during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellite (ARCTAS) mission together with the GEOS-5 CO simulation to examine O3 and NOy in the Arctic and sub-Arctic region and their source attribution. Using a number of marker tracers and their probability density distributions, we distinguish various air masses from the background troposphere and examine their contribution to NOx, O3, and O3 production in the Arctic troposphere. The background Arctic troposphere has mean O3 of approximately 60 ppbv and NOx of approximately 25 pptv throughout spring and summer with CO decreases from approximately 145 ppbv in spring to approximately 100 ppbv in summer. These observed CO, NOx and O3 mixing ratios are not notably different from the values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns despite the significant changes in the past two decades in processes that could have changed the Arctic tropospheric composition. Air masses associated with stratosphere-troposphere exchange are present throughout the mid and upper troposphere during spring and summer. These air masses with mean O3 concentration of 140-160 ppbv are the most important direct sources of O3 in the Arctic troposphere. In addition, air of stratospheric origin is the only notable driver of net O3 formation in the Arctic due to its sustainable high NOx (75 pptv in spring and 110 pptv in summer) and NOy (approximately 800 pptv in spring and approximately 1100 pptv in summer) levels. The ARCTAS measurements present observational evidence suggesting significant conversion of nitrogen from HNO3 to NOx and then to PAN (a net formation of approximately 120 pptv PAN) in summer when air of stratospheric origin is mixed with tropospheric background during stratosphere-to-troposphere transport. These findings imply that an adequate representation of stratospheric O3 and NOy input are essential in accurately simulating O3

  11. Evidence of Stratosphere-to-Troposphere Transport Within a Mesoscale Model and Total Ozone Mapping Spectrometer Total Ozone

    NASA Technical Reports Server (NTRS)

    Olsen, Mark A.; Stanford, John L.

    2001-01-01

    We evaluate evidence for stratospheric mass transport into, and mass remaining in, the troposphere during an intense midlatitude cyclone. Mesoscale forecast model analysis fields from the Mesoscale Analysis and Prediction System were matched with total ozone observations from the Total Ozone Measurement Spectrometer. Combined with parcel back trajectory calculations, the analyses imply that two mechanisms contributed to the mass exchange: (1) An area of dynamically induced exchange was observed on the cyclone's southern edge. Parcels originally in the stratosphere crossed the jet core and were diluted through turbulent mixing with tropospheric air; (2) Diabetic effects reduced parcel potential vorticity (PC) for trajectories traversing precipitation regions, creating a 'PV hole' signature in the center of the cyclone. Air with characteristics of ozone and water vapor found in the lower stratosphere remained in the troposphere. The strength of the latter process may be unusual. Combined with other research, these results suggest that precipitation-induced diabetic effects can significantly modify (either decreasing or increasing) parcel potential vorticity, depending on parcel trajectory configuration with respect to maximum heating regions and jet core. The diabetic heating effect on stratosphere-troposphere exchange (STE) is more important to tropopause erosion than to altering parcel trajectories. In addition, these results underline the importance of using not only PC but also chemical constituents for diagnoses of STE.

  12. Impacts of Boreal wildfire emissions on Arctic tropospheric ozone: a multi-model analysis

    NASA Astrophysics Data System (ADS)

    Arnold, Steve; Emmons, Louisa; Monks, Sarah; Law, Kathy; Tilmes, Simone; Turquety, Solene; Thomas, Jennie; Bouarar, Idir; Raut, Jean-Christophe; Flemming, Johannes; Huijnen, Vincent; Mao, Jingqiu; Duncan, Bryan; Steenrod, Steve; Strode, Sarah; Yoshida, Yasuko

    2013-04-01

    Observations suggest that the Arctic has warmed rapidly in the past few decades compared with observed global-mean temperature increases. Model calculations suggest that changes in short-lived pollutants such as ozone and aerosol may have contributed significantly to this warming. Arctic tropospheric budgets of short-lived pollutants are impacted by long-range transport of gases and aerosols from Europe, Asia and N. America, but also by Boreal wildfires in summer. Our understanding of how Boreal fires impact Arctic budgets of climate-relevant atmospheric constituents is limited, and is reliant on sparse observations and models of tropospheric chemistry. In particular, the role of Boreal fires in the Arctic tropospheric ozone budget is poorly constrained, and has been the subject of some controversy, with different studies suggesting both minor and major roles for fires as a source of Arctic ozone. A better understanding of Boreal fire influence on Arctic ozone and aerosol is essential for improving the reliability of our projections of future Arctic and Northern Hemisphere climate change, especially in light of proposed climate-fire feedbacks which may enhance the intensity and extent of high latitude wildfire under a warming climate. Here we use results from the POLARCAT Model Intercomparison Project (POLMIP) and observations collected in the Arctic troposphere as part of International Polar Year in 2008, to evaluate simulated Arctic tropospheric ozone and how it is influenced by Boreal fire emissions in a series of state-of-the-art global atmospheric chemical transport models. By following large plumes exported from Siberian and North American Boreal fire regions in both the models and observations, we show that different models produce a wide range of influence on Arctic tropospheric ozone from fires, despite using identical emissions and having broadly consistent transport patterns. We demonstrate that the different models display highly varied NOy partitioning

  13. Influences of tropospheric ozone and aerosols on satellite-derived UV

    NASA Astrophysics Data System (ADS)

    McKenzie, Richard

    2003-06-01

    In recent years the availability and quality of UV radiation data have improved appreciably. However, high quality measurements from intercalibrated ground-based spectrometers are available at only a few sites worldwide. Satellite derived UV irradiances, on the other hand, offer the advantages of global coverage and avoid the problems of instrument intercalibrations when investigating geographic differences in UV. However, with the satellite sensors in common use, the retrievals can be subject to errors due to variability in the distribution of ozone and aerosols in the lower atmosphere. Previous studies have shown good agreement between satellite-derived UV and ground-based measurements at pristine locations, but with increasing overestimations of the surface UV at more polluted sites, which are characterized by larger concentrations of ozone and aerosols in the troposphere. Consequently, the contrast in UV between pristine locations and more polluted locations may be underestimated by the satellite retrievals. Here we investigate the relative contribution to these differences due ozone profile differences and aerosol extinction. It is found that both factors contribute to the errors, but that the aerosol effect dominates. Tropospheric aerosols can result in satellite overestimations exceeding 30% in populated regions. Large concentrations of tropospheric ozone also lead to satellite overestimations. Firstly, the total ozone column would be underestimated, and secondly, the underestimated component is disproportionately important because of the increased path length and warmer temperatures in the troposphere. If tropospheric ozone were less than expected, as in more pristine locations, then there would be a tendency for satellite-derived UV to be too large by up to ~ 5%.

  14. Ensemble simulations of the role of the stratosphere in the attribution of northern extratropical tropospheric ozone variability

    NASA Astrophysics Data System (ADS)

    Hess, P.; Kinnison, D.; Tang, Q.

    2015-03-01

    Despite the need to understand the impact of changes in emissions and climate on tropospheric ozone, the attribution of tropospheric interannual ozone variability to specific processes has proven difficult. Here, we analyze the stratospheric contribution to tropospheric ozone variability and trends from 1953 to 2005 in the Northern Hemisphere (NH) mid-latitudes using four ensemble simulations of the free running (FR) Whole Atmosphere Community Climate Model (WACCM). The simulations are externally forced with observed time-varying (1) sea-surface temperatures (SSTs), (2) greenhouse gases (GHGs), (3) ozone depleting substances (ODS), (4) quasi-biennial oscillation (QBO), (5) solar variability (SV) and (6) stratospheric sulfate surface area density (SAD). A detailed representation of stratospheric chemistry is simulated, including the ozone loss due to volcanic eruptions and polar stratospheric clouds. In the troposphere, ozone production is represented by CH4-NOx smog chemistry, where surface chemical emissions remain interannually constant. Despite the simplicity of its tropospheric chemistry, at many NH measurement locations, the interannual ozone variability in the FR WACCM simulations is significantly correlated with the measured interannual variability. This suggests the importance of the external forcing applied in these simulations in driving interannual ozone variability. The variability and trend in the simulated 1953-2005 tropospheric ozone from 30 to 90° N at background surface measurement sites, 500 hPa measurement sites and in the area average are largely explained on interannual timescales by changes in the 30-90° N area averaged flux of ozone across the 100 hPa surface and changes in tropospheric methane concentrations. The average sensitivity of tropospheric ozone to methane (percent change in ozone to a percent change in methane) from 30 to 90° N is 0.17 at 500 hPa and 0.21 at the surface; the average sensitivity of tropospheric ozone to the 100 h

  15. Tropospheric ozone variability over Singapore from August 1996 to December 1999

    NASA Astrophysics Data System (ADS)

    Yonemura, S.; Tsuruta, H.; Maeda, T.; Kawashima, S.; Sudo, S.; Hayashi, M.

    Vertical ozone profiles over Singapore (lat 1°20'N, long 103°53'E) have been monitored by ozonesondes twice a month since August 1996. We report the vertical ozone profiles over Singapore from August 1996 to the end of 1999. During this time, large ozone enhancements occurred during three periods: March-June 1997, September-November 1997, and February-May 1998. These ozone enhancements were larger over Singapore than over Malaysia. Backward trajectory analyses revealed that the enhancements during September-November 1997, and February-May 1998 were associated with biomass burning in Indonesia and Southeast Asia. Outside the three periods, ozone concentrations over Singapore differed from those over Malaysia by not more than 2.5% at altitudes of between 2.6 and 7.6 km and by not more than 12% at altitudes of between 1 and 13.5 km. The minimum ozone concentrations in the middle and the upper troposphere were about 20 ppbv and were observed when the wind was easterly from the Pacific Ocean. Ozone concentrations at the bottom of the troposphere were near zero when the wind was southerly to westerly (from the larger, more urbanized and industrialized part of Singapore and the Strait of Malacca), implying that ozone-destroying reactions were occurring with high concentrations of urban pollutants. We conclude that the ozone enhancements observed in the free troposphere resulted from the effects of extensive biomass burning combined with the modified circulation (suppressed convection of maritime air masses) that occurs during El Niño events.

  16. Recent Biomass Burning in the Tropics and Related Changes in Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke; Chandra, J. R. S.; Duncan, B. N.; Schoeberl, M. R.; Torres, O.; Damon, M. R.; Bhartia, P. K.

    2009-01-01

    Biomass burning is an important source of chemical precursors of tropospheric ozone. In the tropics, biomass burning produces ozone enhancements over broad regions of Indonesia, Africa, and South America including Brazil. Fires are intentionally set in these regions during the dry season each year to clear cropland and to clear land for human/industrial expansion. In Indonesia enhanced burning occurs during dry El Nino conditions such as in 1997 and 2006. These burning activities cause enhancement in atmospheric particulates and trace gases which are harmful to human health. Measurements from the Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) from October 2004-November 2008 are used to evaluate the effects of biomass burning on tropical tropospheric ozone. These measurements show sizeable decreases approx.15-20% in ozone in Brazil during 2008 compared to 2007 which we attribute to the reduction in biomass burning. Three broad biomass burning regions in the tropics (South America including Brazil, western Africa, and Indonesia) were analyzed in the context of OMI/MLS measurements and the Global Modeling Initiative (GMI) chemical transport model developed at Goddard Space Flight Center. The results indicate that the impact of biomass burning on ozone is significant within and near the burning regions with increases of approx.10-25% in tropospheric column ozone relative to average background concentrations. The model suggests that about half of the increases in ozone from these burning events come from altitudes below 3 km. Globally the model indicates increases of approx.4-5% in ozone, approx.7-9% in NO, (NO+NO2), and approx.30-40% in CO.

  17. The Governing Processes and Timescales of Stratosphere-to-Troposphere Transport and its Contribution to Ozone in the Arctic Troposphere

    NASA Technical Reports Server (NTRS)

    Liang, Q.; Douglass, A. R.; Duncan, B. N.; Stolarski, R. S.; Witte, J. C.

    2009-01-01

    We used the seasonality of a combination of atmospheric trace gases and idealized tracers to examine stratosphere-to-troposphere transport and its influence on tropospheric composition in the Arctic. Maximum stratosphere-to-troposphere transport of CFCs and O3 occurs in April as driven by the Brewer-Dobson circulation. Stratosphere-troposphere exchange (STE) occurs predominantly between 40 deg N to 80 deg N with stratospheric influx in the mid-latitudes (30-70 deg N) accounting for 67.81 percent of the air of stratospheric origin in the Northern Hemisphere extratropical troposphere. Transport from the lower stratosphere to the lower troposphere (LT) takes three months on average, one month to cross the tropopause, the second month to travel from the upper troposphere (UT) to the middle troposphere (MT), and the third month to reach the LT. During downward transport, the seasonality of a trace gas can be greatly impacted by wet removal and chemistry. A comparison of idealized tracers with varying lifetimes suggests that when initialized with the same concentrations and seasonal cycles at the tropopause, trace gases that have shorter lifetimes display lower concentrations, smaller amplitudes, and earlier seasonal maxima during transport to the LT. STE contributes to O3 in the Arctic troposphere directly from the transport of O3 and indirectly from the transport of NOy . Direct transport of O3 from the stratosphere accounts for 78 percent of O3 in the Arctic UT with maximum contributions occurring from March to May. The stratospheric contribution decreases significantly in the MT/LT (20.25 percent of total O3) and shows a very weak March.April maximum. Our NOx budget analysis in the Arctic UT shows that during spring and summer, the stratospheric injection of NO y-rich air increases NOx concentrations above the 20 pptv threshold level, thereby shifting the Arctic UT from a regime of net photochemical ozone loss to one of net production with rates as high as +16 ppbv/month.

  18. Support Vector Regression Algorithms in the Forecasting of Daily Maximums of Tropospheric Ozone Concentration in Madrid

    NASA Astrophysics Data System (ADS)

    Ortiz-García, E. G.; Salcedo-Sanz, S.; Pérez-Bellido, A. M.; Gascón-Moreno, J.; Portilla-Figueras, A.

    In this paper we present the application of a support vector regression algorithm to a real problem of maximum daily tropospheric ozone forecast. The support vector regression approach proposed is hybridized with an heuristic for optimal selection of hyper-parameters. The prediction of maximum daily ozone is carried out in all the station of the air quality monitoring network of Madrid. In the paper we analyze how the ozone prediction depends on meteorological variables such as solar radiation and temperature, and also we perform a comparison against the results obtained using a multi-layer perceptron neural network in the same prediction problem.

  19. Ozone vertical flux within the lower troposphere over background areas of west Siberia

    NASA Astrophysics Data System (ADS)

    Antokhin, P. N.; Antokhina, O. Yu.; Belan, S. B.; Belan, B. D.; Kozlov, A. V.; Krasnov, O. A.; Pestunov, D. A.

    2014-11-01

    In this paper the results of the vertical ozone flux profiles calculated within the lower troposphere over background area of west Siberia are presented. The data on the vertical distribution of the ozone and meteorological parameters derived from AN-2 aircraft measurements supplemented by radiosonde launches. Profiles of turbulent diffusion coefficient were calculated based on "K-theory" with the use of nonlocal closure scheme - "Troen and Mahrt". Calculations confirmed earlier findings that the formation of the daytime ozone maximum in the atmospheric boundary layer occurs due to its photochemical production from precursors.

  20. Evaluation of Near-Tropopause Ozone Distributions in the Global Modeling Initiative Combined Stratosphere/Troposphere Model with Ozonesonde Data

    NASA Technical Reports Server (NTRS)

    Considine, David B.; Logan, Jennifer A.; Olsen, Mark A.

    2008-01-01

    The NASA Global Modeling Initiative has developed a combined stratosphere/troposphere chemistry and transport model which fully represents the processes governing atmospheric composition near the tropopause. We evaluate model ozone distributions near the tropopause, using two high vertical resolution monthly mean ozone profile climatologies constructed with ozonesonde data, one by averaging on pressure levels and the other relative to the thermal tropopause. Model ozone is high biased at the SH tropical and NH midlatitude tropopause by approx. 45% in a 4 deg. latitude x 5 deg. longitude model simulation. Increasing the resolution to 2 deg. x 2.5 deg. increases the NH tropopause high bias to approx. 60%, but decreases the tropical tropopause bias to approx. 30%, an effect of a better-resolved residual circulation. The tropopause ozone biases appear not to be due to an overly vigorous residual circulation or excessive stratosphere/troposphere exchange, but are more likely due to insufficient vertical resolution or excessive vertical diffusion near the tropopause. In the upper troposphere and lower stratosphere, model/measurement intercomparisons are strongly affected by the averaging technique. NH and tropical mean model lower stratospheric biases are less than 20%. In the upper troposphere, the 2 deg. x 2.5 deg. simulation exhibits mean high biases of approx. 20% and approx. 35% during April in the tropics and NH midlatitudes, respectively, compared to the pressure averaged climatology. However, relative-to-tropopause averaging produces upper troposphere high biases of approx. 30% and 70% in the tropics and NH midlatitudes. This is because relative-to-tropopause averaging better preserves large cross-tropopause O3 gradients, which are seen in the daily sonde data, but not in daily model profiles. The relative annual cycle of ozone near the tropopause is reproduced very well in the model Northern Hemisphere midlatitudes. In the tropics, the model amplitude of the

  1. Tropical upper tropospheric ozone enhancements due to potential vorticity intrusions over Indian sector

    NASA Astrophysics Data System (ADS)

    Sandhya, M.; Sridharan, S.; Indira Devi, M.; Gadhavi, H.

    2015-09-01

    Influence of potential vorticity (PV) intrusions at 13.5°N over and near Indian sector (50°E-90°E) on tropical upper tropospheric ozone mixing ratio (OMR) variations is demonstrated based on two case studies. Increase of ECMWF (European Centre for Medium-range Weather Forecasting) reanalysis (ERA)-interim OMR in the upper troposphere (200-500 hPa) is observed during the intrusion events consistently in both cases. The OMR also shows similar tongue like structure as PV and it even follows the spatial shift of the PV tongue. In addition, the enhancements in the upper tropospheric OMR during the intrusion events are confirmed using microwave limb sounder (MLS) ozone data at 216 hPa. It is suggested that the existence of strong downdrafts, associated with the ageostrophic circulation due to jet stream, which is inferred from longitude-height cross-section of ERA-interim vertical velocity could bring the ozone further down, though high PV tongue remains only at higher level (above 400 hPa). The importance of these results lies in demonstrating the role of PV intrusion events on the enhancement of tropical upper tropospheric ozone over Indian sector, where the impact of the PV intrusions is not well understood when compared to that over Pacific and Atlantic sectors.

  2. Final Report, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone"

    SciTech Connect

    B. J. Finlayson-Pitts

    2005-06-20

    This document is a final report for the project DE-FG03-98ER62578, "Laboratory Studies of the Role of Sea Salt Bromine in Determining Tropospheric Ozone". It includes a technical summary, collaborations, educational contributions and the peer-reviewed scientific publications that have resulted from this research.

  3. Ozone and Nitric Acid Variability in the Upper Troposphere and Lower Stratosphere Measured during the Polar Aura Validation Experiment

    NASA Astrophysics Data System (ADS)

    Avery, M.; Plant, J.; Dibb, J.; Scheuer, E.; Browell, E.; Hair, J.; Pfister, L.; Shoeberl, M.; Lait, L.

    2005-05-01

    Understanding the response of stratospheric and tropospheric constituents to climate and chemical change requires synthesizing a complex combination of physical and chemical processes that operate simultaneously on a wide range of spatial and temporal scales to produce the large-scale global distributions observed by satellites. However, retrieval algorithms are difficult to develop in the critical upper tropospheric, tropopause and lower stratospheric regions, where the radiative properties of trace gases most affect the global climate. This is because most retrieval algorithms depend on an initial a priori profile assumption based on a geographical measurement climatology, but the actual vertical mixing ratio gradients are large across the tropopause, which varies in height based on the location of geophysical features. In this presentation we show high-resolution, accurate in situ correlative ozone and nitric acid measurements from the NASA DC-8 during the Polar Aura Validation Experiment (PAVE) in January-February of 2005. In addition to providing calibrated correlative measurements, these high-resolution measurements help to characterize the variability of ozone and nitric acid in the near-tropopause region. We use our measurements to illustrate both vertical and horizontal variability under various synoptic conditions encountered during the mission. During late winter ozone acts as a conserved dynamical tracer in the lower stratosphere, and we examine correlations of ozone with measured nitric acid and modeled potential vorticity, as well as calculate the observed ozone variance power spectrum and structure functions to better quantify mixing and eddy dissipation rates at scales that are too fine for the satellite instruments and ozone lidars to resolve, but that span the subrange between the inertial (isotropic) and buoyant (anisotropic) turbulent mixing scales. Accurate characterization of mixing of chemical species and energy dissipation in this subrange

  4. The effect of clouds on photolysis rates and ozone formation in the unpolluted troposphere

    NASA Technical Reports Server (NTRS)

    Thompson, A. M.

    1984-01-01

    The photochemistry of the lower atmosphere is sensitive to short- and long-term meteorological effects; accurate modeling therefore requires photolysis rates for trace gases which reflect this variability. As an example, the influence of clouds on the production of tropospheric ozone has been investigated, using a modification of Luther's two-stream radiation scheme to calculate cloud-perturbed photolysis rates in a one-dimensional photochemical transport model. In the unpolluted troposphere, where stratospheric inputs of odd nitrogen appear to represent the photochemical source of O3, strong cloud reflectance increases the concentration of NO in the upper troposphere, leading to greatly enhanced rates of ozone formation. Although the rate of these processes is too slow to verify by observation, the calculation is useful in distinguishing some features of the chemistry of regions of differing mean cloudiness.

  5. Elevated middle and upper troposphere ozone observed downstream of Atlantic tropical cyclones

    NASA Astrophysics Data System (ADS)

    Jenkins, Gregory S.; Robjhon, Miliaritiana L.; Reyes, Ashford; Valentine, Adriel; Neves, Luis

    2015-10-01

    During the peak period of hurricane activity in the summer of 2010, vertical profiles of ozone using ozonesondes were taken downstream of tropical cyclones in the Western and Eastern Atlantic Ocean basin at Barbados and Cape Verde. Measurements are taken for tropical cyclones Danielle, Earl, Fiona, Gaston, Julia and Igor. The measurements show an increase in ozone mixing ratios with air originating from the tropical cyclones at 5-10 km altitude. We suggest that observed lightning activity associated tropical cyclones and the subsequent production of NOX followed by upper level outflow and subsidence ahead of the tropical cyclones and aged continental outflow from West Africa thunderstorms produced observed increases in ozone mixing ratios. Hurricane Danielle showed the largest changes in ozone mixing ratio with values increasing from 25 ppb to 70 ppb between 22 and 25 August in the middle troposphere, near 450 hPa; warming and drying in the middle and lower troposphere. Measurements of ozone mixing ratios in Cape Verde show higher ozone mixing ratios prior to the passage of tropical storm Julia but low ozone mixing ratios and high relative humidity up to 300 hPa when the storm was in close proximity. This is due most likely the vertically transported from the marine boundary layer.

  6. North American Tropospheric Ozone Sources During Summer 2008 ARCTAS/ARC-IONS Derived from Laminar Identification with Tracers and Fire Maps

    NASA Astrophysics Data System (ADS)

    Thompson, A. M.; Luzik, A. M.; Gallager, S. D.; Oltmans, S. J.; Tarasick, D. W.; Fromm, M.; Forbes, G.; Witte, J. C.; Soja, A.

    2009-05-01

    The ARC-IONS (ARCTAS Intensive Ozonesonde Network Study;, coordinated ozonesonde network, following the model of IONS-04 and IONS-06 [Thompson et al., 2007; 2008], operated over 17 Canadian and US sites in 2008, with daily launches (1-20 April; 26 June-12 July) during A-Train satellite overpasses, ~1300 local. The summer phase of ARC-IONS supported ARCTAS (Arctic Research of the Composition of the Troposphere with Aircraft and Satellites); sampling of ozone, CO and other tracers from ground bases and aircraft operating from Yellowknife (NT) and Cold Lake (AB) in Canada. The laminar identification (LID; Thompson et al., 2008; Yorks et al., 2009) method is applied to ozone and P-T-U profiles to determine ozone sources in the free troposphere. In addition to stratospheric ozone and a mixture of regional pollution-convection-lightning, about half of free tropospheric ozone is made up of recently advected ozone and background, aged ozone. Ensembles of back- trajectories are combined with LID results and satellite maps to extract fire contributions to column ozone over each ARC-IONS site. In addition, each sonde budget is disaggregated with respect to regional fire sources, eg California, western Canada, eastern US. An upper limit of 25% pyrogenic ozone, on average, is obtained from trajectory-fire coincidences over central and western Canada, with the "cleanest" site at Whitehorse (YK) and the most fire-perturbed at Kelowna (BC) and Stonyplain (Edmonton). The fire fraction declines when likely altitude of fire impacts is considered. Western North American sounding sites in 2008 were heavily affected by US west coast and Siberian fires. Eastern Canadian and southern US fires were important sources of ozone over Goose Bay, Egbert and maritime Canada.

  7. Tropospheric Ozone Climatology over Irene, South Africa, From 1990-1994 and 1998-2002

    NASA Technical Reports Server (NTRS)

    Diab, R. D.; Thompson, A. M.; Marl, K.; Ramsay, L.; Coetzee, G. J. R.

    2004-01-01

    This paper describes ozone profiles from sonde data during the period of NASA s TRACE-A and the more recent SHADOZ (Southern Hemisphere Additional Ozonesondes) period. The data were taken by the South African Weather Service at the Irene (25 deg.54 min S; 28 deg. 13 min. E) station near Pretoria, South Africa, an area that is a unique mixture of local industry, heavy biofuels use and importation of biomass burning ozone from neighboring countries to the north. The main findings are: (1) With its geographical position at the edge of the subtropical transition zone, mid- latitude dynamical influences are evident at Irene, predominantly in winter when upper tropospheric ozone is enhanced as a result of stratospheric-tropospheric exchange. (2) There has been an increase in the near-surface ozone amount between the early 1990s and a decade later, presumably due to an influx of rural population toward the Johannesburg-Pretoria area, as well as with industrial growth and development. (3) Most significant for developing approaches for satellite ozone profile climatologies, cluster analysis has enabled the delineation of a background and "most polluted" profile. Enhancements of at least 30% occur throughout the troposphere in spring and in certain layers increases of 100 % are observed.

  8. A modeling study of effective radiative forcing and climate response due to tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Xie, Bing; Zhang, Hua; Wang, Zhili; Zhao, Shuyun; Fu, Qiang

    2016-07-01

    This study simulates the effective radiative forcing (ERF) of tropospheric ozone from 1850 to 2013 and its effects on global climate using an aerosol-climate coupled model, BCC AGCM2.0.1 CUACE/Aero, in combination with OMI (Ozone Monitoring Instrument) satellite ozone data. According to the OMI observations, the global annual mean tropospheric column ozone (TCO) was 33.9 DU in 2013, and the largest TCO was distributed in the belts between 30°N and 45°N and at approximately 30°S; the annual mean TCO was higher in the Northern Hemisphere than that in the Southern Hemisphere; and in boreal summer and autumn, the global mean TCO was higher than in winter and spring. The simulated ERF due to the change in tropospheric ozone concentration from 1850 to 2013 was 0.46 W m-2, thereby causing an increase in the global annual mean surface temperature by 0.36°C, and precipitation by 0.02 mm d-1 (the increase of surface temperature had a significance level above 95%). The surface temperature was increased more obviously over the high latitudes in both hemispheres, with the maximum exceeding 1.4°C in Siberia. There were opposite changes in precipitation near the equator, with an increase of 0.5 mm d-1 near the Hawaiian Islands and a decrease of about -0.6 mm d-1 near the middle of the Indian Ocean.

  9. Chemistry-Transport Modeling of the Satellite Observed Distribution of Tropical Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Peters, Wouter; Krol, Maarten; Dentener, Frank; Thompson, Anne M.; Leloeveld, Jos; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    We have compared the 14-year record of satellite derived tropical tropospheric ozone columns (TTOC) from the NIMBUS-7 Total Ozone Mapping Spectrometer (TOMS) to TTOC calculated by a chemistry-transport model (CTM). An objective measure of error, based on the zonal distribution of TTOC in the tropics, is applied to perform this comparison systematically. In addition, the sensitivity of the model to several key processes in the tropics is quantified to select directions for future improvements. The comparisons indicate a widespread, systematic (20%) discrepancy over the tropical Atlantic Ocean, which maximizes during austral Spring. Although independent evidence from ozonesondes shows that some of the disagreement is due to satellite over-estimate of TTOC, the Atlantic mismatch is largely due to a misrepresentation of seasonally recurring processes in the model. Only minor differences between the model and observations over the Pacific occur, mostly due to interannual variability not captured by the model. Although chemical processes determine the TTOC extent, dynamical processes dominate the TTOC distribution, as the use of actual meteorology pertaining to the year of observations always leads to a better agreement with TTOC observations than using a random year or a climatology. The modeled TTOC is remarkably insensitive to many model parameters due to efficient feedbacks in the ozone budget. Nevertheless, the simulations would profit from an improved biomass burning calendar, as well as from an increase in NOX abundances in free tropospheric biomass burning plumes. The model showed the largest response to lightning NOX emissions, but systematic improvements could not be found. The use of multi-year satellite derived tropospheric data to systematically test and improve a CTM is a promising new addition to existing methods of model validation, and is a first step to integrating tropospheric satellite observations into global ozone modeling studies. Conversely

  10. Development of a Portable, Ground-based Ozone Lidar Instrument for Tropospheric Ozone Research and Educational Training

    NASA Technical Reports Server (NTRS)

    Chyba, Thomas; Zemker, Thomas; Fishman, Jack (Technical Monitor)

    1999-01-01

    The objective of this research project is to develop a portable, eye-safe, ground-based ozone lidar instrument specialized for ozone differential absorption lidar (DIAL) measurements in the troposphere. This research project directly supports the goal of NASA's Earth Science Enterprise to understand the distribution and budget of tropospheric ozone (objective 1.5 of the Earth Science Strategic Enterprise Plan, 1998-2002). It can participate in ground validation experiments for TES, a tropospheric ozone satellite mission due to be launched in 2002. It can also be utilized for correlative ground measurements in future GTE (Global Tropospheric Experiment) and space-based ozone lidar missions, such as ORACLE. Multiple ground-based ozone lidar systems would improve the data obtained through current ozone-sonde networks. This prototype instrument could to serve as the basic unit for these and other future monitoring projects requiring multi-instrument networks, such as that proposed for the Global Tropospheric Ozone Project (GTOP). GTOP is currently being formulated by a scientific panel of the International Global Atmospheric Chemistry Project to meet its goal to better understand the processes that control the global distribution of tropospheric ozone. In order for the lidar to be widely deployed in networks, it must be fairly easy to use and maintain as well as being cost-competitive with a ground station launching ozonesondes several times a day. A second 2-year grant to continue this effort with students participating in ground tests and system improvements has been awarded by the Office of Equal Employment Opportunities (OEOP). This project also supports existing NASA lidar missions through its development of advanced, compact lidar technology. Innovations in both transmitters and receivers have been made in this project. Finally, this system could be modified in the future to probe more deeply into the stratosphere. This could be accomplished by increasing the

  11. Preliminary tropospheric ozone DIAL, water vapour, and aerosol lidar measurements during ARC-IONS

    NASA Astrophysics Data System (ADS)

    Strawbridge, Kevin B.; Firanski, Bernard J.

    2009-09-01

    A new lidar instrument, dubbed AeRO (Aerosol Raman Ozone) Lidar, is being developed at Environment Canada's Centre For Atmospheric Research Experiments (CARE). The new system will use three lasers to simultaneously measure ozone, water vapour and aerosol profiles (including extinction) from near ground to the tropopause. The main thrust will focus on understanding Air Quality within the airshed with the capability of looking at Stratospheric Tropospheric Exchange (STE) processes to determine the magnitude and frequency of such events leading to elevated levels of tropospheric ozone. In addition a wind profiler through a partnership with University of Western Ontario will soon be deployed to CARE to provide complementary observations of the tropopause. The lidar participated in the ARC-IONS field campaign during April and July of 2008. During the field campaign, daily ozonesondes were released to further compliment the lidar measurements. Details of the system design and preliminary results from the lidar measurements will be presented.

  12. Raman shifting of KrF laser radiation for tropospheric ozone measurements

    NASA Technical Reports Server (NTRS)

    Grant, William B.; Browell, Edward V.; Higdon, Noah S.; Ismail, Syed

    1991-01-01

    The differential absorption lidar (DIAL) measurement of tropospheric ozone requires use of high average power UV lasers operating at two appropriate DIAL wavelengths. Laboratory experiments have demonstrated that a KrF excimer laser can be used to generate several wavelengths with good energy conversion efficiencies by stimulated Raman shifting using hydrogen (H2) and deuterium (D2). Computer simulations for an airborne lidar have shown that these laser emissions can be used for the less than 5 percent random error, high resolution measuremment of ozone across the troposphere using the DIAL technique. In the region of strong ozone absorption, laser wavelengths of 277.0 and 291.7 nm were generated using H2 and D2, respectively. In addition, a laser wavelength at 302.0 nm was generated using two cells in series, with the first containing D2 and the second containing H2. The energy conversion efficiency for each wavelength was between 14 and 27 percent.

  13. Boreal fire influence on Arctic tropospheric ozone, ecosystems and climate forcing

    NASA Astrophysics Data System (ADS)

    Arnold, S.; Monks, S. A.; Emmons, L. K.; Sitch, S.; Rap, A.; Law, K.; Tilmes, S.; Lamarque, J.

    2013-12-01

    Temperature observations show that the Arctic has warmed rapidly in the past few decades compared to the northern hemisphere as a whole. Model calculations suggest that changes in short-lived pollutants such as ozone and aerosol may have contributed significantly to this warming. Arctic tropospheric budgets of short-lived pollutants are impacted by both local anthropogenic emissions and by long-range transport of gases and aerosols from Europe, Asia and N. America, but also by local Boreal wildfires in summer. Our understanding of how fires impact Arctic budgets of climate-relevant atmospheric constituents is limited, and is reliant on sparse observations and models of tropospheric chemistry. A better understanding of Boreal fire influence on Arctic ozone is essential for improving the reliability of our projections of future Arctic and Northern Hemisphere climate change, especially in light of proposed climate-fire feedbacks which may enhance the intensity and extent of high latitude wildfire under a warming climate. Using the NCAR Community Earth System Model (CESM) and a scheme for tagging and tracking NOx emitted by high latitude wildfires and its resultant tropospheric ozone production, we investigate the impacts of fire-sourced ozone on summertime high latitude radiative forcing and on ecosystems. The large fraction of NOy present as PAN in the Arctic suggests there may be a strong sensitivity of NOy and ozone enhancement to the efficiency of vertical transport from source regions, which determines the stability of PAN as air is advected poleward. We use these simulations and aircraft observations to characterise the vertical distributions of sensitivities of Arctic NOy and ozone to remote anthropogenic and local widlfire sources, and use an offline radiative transfer model to quantify impacts on local ozone radiative forcing. We compare these vertical sensitivities with those of a primary-emitted CO-like source tracer, to investigate the role of PAN

  14. The role of vegetation for tropospheric ozone balance: possible changes under future climate conditions

    NASA Astrophysics Data System (ADS)

    Wu, Cheng; Pullinen, Iida; Andres, Stefanie; Carriero, Giulia; Fares, Silvano; Hacker, Lina; Kiendler-Scharr, Astrid; Kleist, Einhard; Paoletti, Elena; Wahner, Andreas; Wildt, Jürgen; Mentel, Thomas F.

    2015-04-01

    Ozone (O3) is a phytotoxic trace gas in the troposphere where it is photochemically produced from volatile organic compounds (VOCs) and nitrogen oxides (NOx). The dominant sink of O3 in the air over areas with dense plant cover is dry deposition on plant surfaces. However, plants can also contribute to photochemical O3 formation because they emit biogenic VOCs (BVOCs). In this study, the role of vegetation for tropospheric ozone balance was investigated by considering the following processes: O3 depletion by dry deposition on plant surfaces, O3 depletion by gas phase reactions with plant emitted BVOCs, and photochemical O3 production from these BVOCs. Furthermore, drought and heat stress were applied to the plants, and the stress-induced changes of plant performance and the subsequent changes regarding the tropospheric ozone balance were investigated. Dry deposition of O3 in unstressed plants was dominated by O3 uptake through the plants stomata with negligible losses on cuticle and stem. For strong BVOC emitters, O3 destruction by gas phase reactions with BVOCs was significant at low NOx conditions. Switching from low NOx to high NOx conditions led to O3 production. A ratio of O3 formation rates over BVOC loss rates was measured for α-pinene as single BVOC and for BVOC mixtures emitted from real plants. For O3 formation under BVOC limited conditions, this ratio was in the range of 2-3 ppb/ppb. The ratio of O3 uptake/BVOC emission reflects the capability of a plant as a potential source of O3, while NOx concentrations and the BVOC/NOx ratio determine whether the emitted BVOCs act as an additional sink or a source of O3. O3 uptake rates and BVOC emission rates are affected by environmental variables such as temperature, light intensity and stresses to plants. The impacts of these variables on the two processes are different and thus the capability of a plant to be a source of O3 is also affected. As future climate change will bring more and intense heat waves and

  15. Improvement of GOME-2 Tropospheric Ozone Profile Retrievals from Joint UV/Visible Measurements

    NASA Astrophysics Data System (ADS)

    Liu, X.; Zoogman, P.; Chance, K.; Cai, Z.; Nowlan, C. R.

    2015-12-01

    It has been shown that adding visible measurements in the Chappuis band to UV measurements in the Hartley/Huggins bands can significantly enhance retrieval sensitivity to lower tropospheric ozone from backscattered solar radiances due to deeper photon penetration in the visible to the surface than in the ultraviolet. The first NASA EVI TEMPO (Tropospheric Emissions: Monitoring of Pollution) instrument is being developed to measure backscattered solar radiation in two channels (~290-490 and 540-740 nm) and make atmospheric pollution measurements over North America from the Geostationary orbit. However, this retrieval enhancement has yet to be solidly demonstrated from existing measurements due to the weak ozone absorption in the visible and strong interference from surface reflectance and the requirement of accurate radiometric calibration across different spectral channels. We present GOME-2 retrievals from joint UV/visible measurements using the SAO optimal estimation based ozone profile retrieval algorithm, to directly explore the retrieval improvement in lower tropospheric ozone from additional visible measurements. To reduce the retrieval interference from surface reflectance, we add characterization of surface spectral reflectance in the visible based on ASTER and other surface reflectance spectra and MODIS BRDF climatology into the ozone profile algorithm using two approaches: fitting several EOFs (Empirical Orthogonal Functions) and scaling reflectance spectra. We also perform empirical radiometric calibration of the GOME-2 data based on radiative transfer simulations. We evaluate the retrieval improvement of joint UV/visible retrieval over the UV retrieval. These results clearly show the potential of using the visible to improve lower tropospheric ozone retrieval.

  16. Global Radiative Forcing of Coupled Tropospheric Ozone and Aerosols in a Unified General Circulation Model

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Seinfeld, John H.; Adams, Peter J.; Mickley, Loretta J.

    2008-01-01

    Global simulations of sea salt and mineral dust aerosols are integrated into a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II', that simulates coupled tropospheric ozone-NOx-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols. The fully coupled gas-aerosol unified GCM allows one to evaluate the extent to which global burdens, radiative forcing, and eventually climate feedbacks of ozone and aerosols are influenced by gas-aerosol chemical interactions. Estimated present-day global burdens of sea salt and mineral dust are 6.93 and 18.1 Tg with lifetimes of 0.4 and 3.9 days, respectively. The GCM is applied to estimate current top of atmosphere (TOA) and surface radiative forcing by tropospheric ozone and all natural and anthropogenic aerosol components. The global annual mean value of the radiative forcing by tropospheric ozone is estimated to be +0.53 W m(sup -2) at TOA and +0.07 W m(sup -2) at the Earth's surface. Global, annual average TOA and surface radiative forcing by all aerosols are estimated as -0.72 and -4.04 W m(sup -2), respectively. While the predicted highest aerosol cooling and heating at TOA are -10 and +12 W m(sup -2) respectively, surface forcing can reach values as high as -30 W m(sup -2), mainly caused by the absorption by black carbon, mineral dust, and OC. We also estimate the effects of chemistry-aerosol coupling on forcing estimates based on currently available understanding of heterogeneous reactions on aerosols. Through altering the burdens of sulfate, nitrate, and ozone, heterogeneous reactions are predicted to change the global mean TOA forcing of aerosols by 17% and influence global mean TOA forcing of tropospheric ozone by 15%.

  17. Observation of ozone enhancement in the lower troposphere over East Asia from a space-borne ultraviolet spectrometer

    NASA Astrophysics Data System (ADS)

    Hayashida, S.; Liu, X.; Ono, A.; Yang, K.; Chance, K.

    2015-01-01

    We report observations from space using ultraviolet (UV) radiance for significant enhancement of ozone in the lower troposphere over Central and Eastern China (CEC). The recent retrieval products of the Ozone Monitoring Instrument (OMI) onboard the Earth Observing System (EOS)/Aura satellite revealed the spatial and temporal variation of ozone distributions in multiple layers in the troposphere. We compared the OMI-derived ozone over Beijing with airborne measurements by the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. The correlation between OMI and MOZAIC ozone in the lower troposphere was reasonable, which assured the reliability of OMI ozone retrievals in the lower troposphere under enhanced ozone conditions. The ozone enhancement was clearly observed over CEC, with Shandong Province as its center, and most notable in June in any given year. Similar seasonal variations were observed throughout the nine-year OMI measurement period of 2005 to 2013. The ozone enhancement in June was associated with the enhancement of carbon monoxide (CO) and hotspots, which is consistent with previous studies of in-situ measurements such those made by the MTX2006 campaign. A considerable part of this ozone enhancement could be attributed to the emissions of ozone precursors from open crop residue burning (OCRB) after the winter wheat harvest, in addition to emissions from industrial activities and automobiles. The ozone distribution presented in this study is also consistent with some model studies that apply emissions from OCRB. The lower tropospheric ozone distribution is first shown from OMI retrieval in this study, and the results will be useful in clarifying any unknown factors that influence ozone distribution by comparison with model simulations.

  18. Role of Climate Change in Global Predictions of Future Tropospheric Ozone and Aerosols

    NASA Technical Reports Server (NTRS)

    Liao, Hong; Chen, Wei-Ting; Seinfeld, John H.

    2006-01-01

    A unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies general circulation model II is applied to simulate an equilibrium CO2-forced climate in the year 2100 to examine the effects of climate change on global distributions of tropospheric ozone and sulfate, nitrate, ammonium, black carbon, primary organic carbon, secondary organic carbon, sea salt, and mineral dust aerosols. The year 2100 CO2 concentration as well as the anthropogenic emissions of ozone precursors and aerosols/aerosol precursors are based on the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES) A2. Year 2100 global O3 and aerosol burdens predicted with changes in both climate and emissions are generally 5-20% lower than those simulated with changes in emissions alone; as exceptions, the nitrate burden is 38% lower, and the secondary organic aerosol burden is 17% higher. Although the CO2-driven climate change alone is predicted to reduce the global O3 concentrations over or near populated and biomass burning areas because of slower transport, enhanced biogenic hydrocarbon emissions, decomposition of peroxyacetyl nitrate at higher temperatures, and the increase of O3 production by increased water vapor at high NOx levels. The warmer climate influences aerosol burdens by increasing aerosol wet deposition, altering climate-sensitive emissions, and shifting aerosol thermodynamic equilibrium. Climate change affects the estimates of the year 2100 direct radiative forcing as a result of the climate-induced changes in burdens and different climatological conditions; with full gas-aerosol coupling and accounting for ozone and direct radiative forcings by the O2, sulfate, nitrate, black carbon, and organic carbon are predicted to be +0.93, -0.72, -1.0, +1.26, and -0.56 W m(exp -2), respectively, using present-day climate and year 2100 emissions, while they are predicted to be +0.76, -0.72, 0.74, +0.97, and -0.58 W m(exp -2

  19. Global Assimilation of EOS-Aura Data as a Means of Mapping Ozone Distribution in the Lower Stratosphere and Troposphere

    NASA Technical Reports Server (NTRS)

    Wargan, Krzysztof; Olsen, M.; Douglass, A.; Witte, J.; Strahan, S.; Livesey, N.

    2012-01-01

    Ozone in the lower stratosphere and the troposphere plays an important role in forcing the climate. However, the global ozone distribution in this region is not well known because of the sparse distribution of in-situ data and the poor sensitivity of satellite based observations to the lowermost of the atmosphere. The Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments on EOS-Aura provide information on the total ozone column and the stratospheric ozone profile. This data has been assimilated into NASA s Global Earth Observing System, Version 5 (GEOS-5) data assimilation system (DAS). We will discuss the results of assimilating three years of OMI and MLS data into GEOS-5. This data was assimilated alongside meteorological observations from both conventional sources and satellite instruments. Previous studies have shown that combining observations from these instruments through the Trajectory Tropospheric Ozone Residual methodology (TTOR) or using data assimilation can yield useful, yet low biased, estimates of the tropospheric ozone budget. We show that the assimilated ozone fields in this updated version of GEOS-5 exhibit an excellent agreement with ozone sonde and High Resolution Dynamics Limb Sounder (HIRDLS) data in the lower stratosphere in terms of spatial and temporal variability as well as integrated ozone abundances. Good representation of small-scale vertical features follows from combining the MLS data with the assimilated meteorological fields. We then demonstrate how this information can be used to calculate the Stratosphere - Troposphere Exchange of ozone and its contribution to the tropospheric ozone column in GEOS-5. Evaluations of tropospheric ozone distributions from the assimilation will be made by comparisons with sonde and other in-situ observations.

  20. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Astrophysics Data System (ADS)

    Stevenson, D. S.; Young, P. J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; Folberth, G. A.; Rumbold, S. T.; Collins, W. J.; MacKenzie, I. A.; Doherty, R. M.; Zeng, G.; van Noije, T. P. C.; Strunk, A.; Bergmann, D.; Cameron-Smith, P.; Plummer, D. A.; Strode, S. A.; Horowitz, L.; Lee, Y. H.; Szopa, S.; Sudo, K.; Nagashima, T.; Josse, B.; Cionni, I.; Righi, M.; Eyring, V.; Conley, A.; Bowman, K. W.; Wild, O.; Archibald, A.

    2013-03-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation) in RFs of ±17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44±12%), nitrogen oxides (31 ± 9%), carbon monoxide (15 ± 3%) and non-methane volatile organic compounds (9 ± 2%); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m-2 DU-1, a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m-2; relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some coherent responses of ozone to climate change: decreases in the

  1. Tropospheric Ozone Changes, Radiative Forcing and Attribution to Emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Technical Reports Server (NTRS)

    Stevenson, D.S.; Young, P.J.; Naik, V.; Lamarque, J.-F.; Shindell, D. T.; Voulgarakis, A.; Skeie, R. B.; Dalsoren, S. B.; Myhre, G.; Berntsen, T. K.; Folberth, G. A.; Rumbold, S. T.; Collins, W. J.; MacKenzie, I. A.; Doherty, R. M.; Zeng, G.; vanNoije, T. P. C.; Strunk, A.; Bergmann, D.; Cameron-Smith, P.; Plummer, D. A.; Strode, S. A.; Horowitz, L.; Lee, Y. H.; Szopa, S.; Sudo, K.; Nagashima, T.; Josse, B.; Cionni, I.; Righi, M.; Eyring, V.; Conley, A.; Bowman, K. W.; Wild, O.; Archibald, A.

    2013-01-01

    Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m-2. The model range of pre-industrial to present-day changes in O3 produces a spread (+/-1 standard deviation) in RFs of +/-17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of +/-10 percent. Applying two different tropopause definitions gives differences in RFs of +/-3 percent. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of +/-30 percent for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44+/-12 percent), nitrogen oxides (31 +/- 9 percent), carbon monoxide (15 +/- 3 percent) and non-methane volatile organic compounds (9 +/- 2 percent); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m(-2) DU(-1), a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m(-2); relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some

  2. SHADOZ (Southern Hemisphere ADditional Ozonesondes): A Look at the First Three Years' (1998-2000) Tropospheric Ozone Data

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Bhartia, Pawan K. (Technical Monitor)

    2001-01-01

    The first climatological overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropical and subtropics is based on ozone sounding data from 10 sites comprising the Southern Hemisphere ADditional OZonesondes (SHADOZ) network. The period covered is 1998-2000. Observations were made over: Ascension Island; Nairobi, Kenya; Irene, South Africa; RCunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natai, Brazil. Campaign data were collected on a trans-Atlantic oceanographic cruise and during SAFARI-2000 in Zambia. The ozone data, with simultaneous temperature profiles to approx. 7 hPa and relative humidity to approx. 200 hPa, reside at an open archive: . SHADOZ ozone time-series and profiles give a perspective on tropical total, stratospheric and tropospheric ozone in 1998-2000. Prominent features are highly variable tropospheric ozone, a zonal wave-one pattern in total (and tropospheric) column ozone, and signatures of the Quasi-Biennial Oscillation (QBO) in stratospheric ozone. Total, stratospheric and tropospheric column ozone amounts peak between August and November and are lowest between March and May. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the Indian Ocean Dipole, ENSO, and Madden-Julian circulation on convective mixing. Pollution transport from Africa, South American and the Maritime Continent is a seasonal feature. Tropospheric ozone seasonality over the Atlantic Basin shows effects of regional subsidence and recirculation as well as biomass burning. Dynamical and chemical influences appear to be of comparable magnitude.

  3. Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology 2. Tropospheric variability and the zonal wave-one

    NASA Astrophysics Data System (ADS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Schmidlin, Francis J.; Logan, Jennifer A.; Fujiwara, Masatomo; Kirchhoff, Volker W. J. H.; Posny, FrançOise; Coetzee, Gert J. R.; Hoegger, Bruno; Kawakami, Shuji; Ogawa, Toshihiro; Fortuin, J. P. F.; Kelder, H. M.

    2003-01-01

    The first view of stratospheric and tropospheric ozone variability in the Southern Hemisphere tropics is provided by a 3-year record of ozone soundings from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network (http://croc.gsfc.nasa.gov/shadoz). Observations covering 1998-2000 were made over Ascension Island, Nairobi (Kenya), Irene (South Africa), Réunion Island, Watukosek (Java), Fiji, Tahiti, American Samoa, San Cristóbal (Galapagos), and Natal (Brazil). Total, stratospheric, and tropospheric column ozone amounts usually peak between August and November. Other features are a persistent zonal wave-one pattern in total column ozone and signatures of the quasi-biennial oscillation (QBO) in stratospheric ozone. The wave-one is due to a greater concentration of free tropospheric ozone over the tropical Atlantic than the Pacific and appears to be associated with tropical general circulation and seasonal pollution from biomass burning. Tropospheric ozone over the Indian and Pacific Oceans displays influences of the waning 1997-1998 El Niño, seasonal convection, and pollution transport from Africa. The most distinctive feature of SHADOZ tropospheric ozone is variability in the data, e.g., a factor of 3 in column amount at 8 of 10 stations. Seasonal and monthly means may not be robust quantities because statistics are frequently not Gaussian even at sites that are always in tropical air. Models and satellite retrievals should be evaluated on their capability for reproducing tropospheric variability and fine structure. A 1999-2000 ozone record from Paramaribo, Surinam (6°N, 55°W) (also in SHADOZ) shows a marked contrast to southern tropical ozone because Surinam is often north of the Intertropical Convergence Zone (ITCZ). A more representative tropospheric ozone climatology for models and satellite retrievals requires additional Northern Hemisphere tropical data.

  4. Evaluation of Aura/OMI Total Column Ozone and Tropospheric Ozone Residual Products using Ozonesonde Profiles from the ARCIONS Campaign

    NASA Astrophysics Data System (ADS)

    Witte, J.; Schoeberl, M.; Thompson, A. M.; Tarasick, D.; Oltmans, S.; Johnson, B.; Davies, J.

    2009-05-01

    During the Arctic Intensive Ozonesonde Network Study (ARCIONS), a large number of sites located over the middle to high latitudes of North America launched daily ozonesondes in the spring (April) and summer (June/July) of 2008. We take advantage of the large number of launches at high northern latitudes to examine the retrieval accuracy of Aura's Ozone Monitoring Instrument (OMI) Total Column Ozone (TCO) and derived Tropospheric Ozone Residual (TOR) products with the equivalent integrated column amounts from ozonesondes with the SBUV/SAGE climatology add-on that estimates the ozone column amounts from the top of the sonde profile to the top of the atmosphere. We find that the OMI TCO and TOR tend to underestimate the sondes for all sites and both seasons. TCO differences between OMI and the sondes are found to be within 10%, while TOR-Sonde differences are observed to be as high as 50% at a number of sites, regardless of latitude and season. TCO amounts from OMI compared to those sonde sites located above 50N are found to be typically over 375 DU in April 2008 while June/July values are clustered around 300-350 DU. Below 50N, OMI-Sonde comparisons show less seasonal separation in total column ozone amounts. Comparisons between the TOR product and sonde integrated tropospheric column (ITC) show no apparent difference between spring and summer. Large differences in troposphere amounts occur even though tropopause heights compare to within just a few percent. Evaluation of the stratospheric column amounts between the ARCIONS sondes and Aura's Microwave Limb Sounder instrument may also be presented. Further investigation into a preliminary method of improving the TOR product using sondes as a validation source shows promise, particularly at high latitudes.

  5. Weekly and Decadal Changes in NOx Emissions and Tropospheric Ozone

    NASA Astrophysics Data System (ADS)

    Marr, L. C.; Harley, R. A.

    2004-12-01

    Variations in air pollutant emissions and ambient concentrations on both weekly and decadal time scales can be used to test our understanding of atmospheric responses to changes in anthropogenic forcing. Combining records of fuel sales and on-road measurements of vehicle activity and emissions, we have estimated motor vehicle emissions by hour and day of week, separately for gasoline and diesel-powered vehicles. Between 1990 and 2000, emissions of nitrogen oxides (NOx) from motor vehicles in California decreased by more than 30%. However, NOx emissions from heavy-duty diesel trucks actually increased by over 40%, offsetting some of the reductions in light-duty vehicle emissions. During the past two decades, the occurrence of higher ozone levels on weekends, a phenomenon known as the weekend effect, has become more widespread in California. The effect impacted 11% of surface observation sites in 1980-84 and 38% in 1995-1999. Results of chemical transport modeling show that the primary cause of the weekend ozone effect is the large decrease in NOx emissions due to a ~75% reduction in diesel truck traffic on weekends. Areas where ozone formation is VOC-sensitive therefore can experience higher ozone concentrations on weekends. Long-term (decadal) changes in anthropogenic emissions have produced a shift towards greater VOC-sensitivity, and the weekend ozone effect has grown more prevalent because diesel trucks now account for over 50% of total motor vehicle NOx emissions.

  6. Comparison of lower tropospheric ozone columns observed by DIAL and GOSAT TANSO-FTS TIR

    NASA Astrophysics Data System (ADS)

    Uchino, O.; Sakai, T.; Nagai, T.; Morino, I.; Ohyama, H.; Kawakami, S.; Shiomi, K.; Kawasaki, T.; Akaho, T.; Okumura, H.; Arai, K.; Matsunaga, T.; Yokota, T.

    2013-12-01

    Ozone plays important roles in climate change and air quality. We have been improving the ozone DIfferential Absorption Lidar (DIAL) installed at Saga (33.24N, 130.29E), Japan in March 2011. Current DIAL consists of four Stimulated Raman Scattering lines (276, 287, 299, and 312 nm) which are generated by the fourth harmonic (266 nm) of a Nd:YAG laser and a 2-m Raman cell filled with 8-atm CO2 gas, and 10-cm and 50-cm dia. receiving telescopes. With this DIAL, ozone profiles could be measured from ~ 300 m to 6 km~10 km altitude. Total and tropospheric ozone columns have been retrieved from the Thermal And Near infrared Sensor for carbon Observation-Fourier Transform Spectrometer, measuring in the Thermal InfraRed (TANSO-FTS TIR) onboard the Greenhouse gases Observing SATellite (GOSAT) launched on 23, January 2009. Lower tropospheric ozone columns between 1 km and 6 km retrieved from GOSAT TANSO-FTS TIR (9.6 μm band) within ×1 degree longitude/latitude centered at DIAL were compared with those of DIAL data in 2012 which were applied with GOSAT TANSO-FTS TIR averaging kernels. Although GOSAT TANSO-FTS TIR data were lower than DIAL data by 10×11%, they were in reasonable agreement with a correlation coefficient of 0.79. Seasonal variations of lower tropospheric ozone columns are clearly seen, and high ozone mixing ratio events around 2 km altitude observed by DIAL are reported.

  7. Improving the Current Understanding of the Evolution and Vertical Processes of Tropospheric Ozone Using a Ground Based Differential Absorption Lidar

    NASA Astrophysics Data System (ADS)

    Sullivan, John T.

    Although characterizing the interactions of ozone throughout the entire troposphere are important for health and climate processes, there is a lack of routine measurements of vertical profiles within the United States. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) has been developed and validated within the Tropospheric Ozone Lidar Network (TOLNet). Two scientifically interesting ozone episodes are presented that were observed during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER AQ) campaign at Ft. Collins, Colorado. The GSFC TROPOZ DIAL measurements are analyzed alongside aircraft spirals over the lidar site, co-located ozonesonde launches, aerosol lidar profiles and other TOLNet ozone lidar profiles. In both case studies, back trajectories, meteorological maps, and comparisons to air quality models are presented to better explain the sources and evolution of ozone. The first case study, occurring between 22-23 July 2014, indicates enhanced concentrations of ozone at Ft. Collins during nighttime hours, which was due to the complex recirculation of ozone within the foothills of the Rocky Mountain region. Although quantifying the ozone increase aloft during recirculation episodes has been historically difficult, results indicate that an increase of 20 - 30 ppbv of ozone at the Ft. Collins site has been attributed to this recirculation. The second case, occurring between Aug 4-8th 2014, characterizes a dynamical exchange of ozone between the stratosphere and the troposphere. This case, along with seasonal model parameters from previous years, is used to estimate

  8. Role of deep convective in modulating tropospheric column ozone over Northern region of India: Case study of 2002

    NASA Astrophysics Data System (ADS)

    Kulkarni, Santosh; Ghude, Sachin; Beig, G.

    2012-07-01

    The present study is an attempt to examine some of the probable causes for the unusually low tropospheric column ozone observed over the Eastern India during the exceptional drought event in July 2002. The analysis presented here aimed to characterize the possible link of the convective transport and tropospheric ozone distribution over the highly polluted northern plain of India. We examined horizontal wind and omega (vertical velocity) anomalies over the Indian region to understand the large scale dynamical processes prevailed during July 2002. It was found that, instead of normal large scale ascent over the Indian region, the air was descending in the middle and lower troposphere over vast part of India. This configuration was apparently responsible for less convective upwelling of precursors and likely caused less photochemical ozone formation in the free troposphere over the Eastern Indian during July 2002. The deep convection during Indian summer monsoon may thus have a significant role in regulating the chemical cycles associated with the change in tropospheric ozone over the Indian region. This study has shown that anomalous low TOR values in July 2002 over the eastern Indian region can be linked to the reduced transport of the precursors in the free troposphere than in normal years. To examine this effect the study of climatology of ozone over the period 2000-2009 has been done using vertical profiles data from ozonosonde dataset over three stations in India. Keyword: Tropospheric ozone - Convection - South Asia - Pollution

  9. Observational and theoretical evidence in support of a significant in-situ photochemical source of tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Fishman, J.; Solomon, S.; Crutzen, P. J.

    1979-01-01

    The latitudinal and seasonal variation of ozone in the troposphere is discussed. Of particular interest is the asymmetrical behavior of this gas with respect to the two hemispheres. These asymmetries, when coupled with a diagnostic photochemical model of the troposphere, lends support to the view that ozone cannot be viewed as an inert tracer of stratospheric origin. In the calculations it is noted that it is likely that the budgets of carbon monoxide and tropospheric ozone may be quite dependent on each other and the calculations are discussed in light of the uncertainty which currently exists about representative global tropospheric background concentrations of the nitrogen oxides. In addition, the seasonal variation of excess (C-14)O2 (a stratospheric tracer) is examined and compared with the seasonal ozone variation during the same period of observations at the same location and altitudes. The distinct maxima for ozone found during the summer in the lower troposphere are not present for the (C-14)O2 data. This finding likewise suggests that photochemical processes taking place in the troposphere are an important source term for tropospheric ozone.

  10. Anthropogenic forcing on tropospheric ozone and OH since preindustrial times

    NASA Astrophysics Data System (ADS)

    Wang, Yuhang; Jacob, Daniel J.

    1998-12-01

    A global three-dimensional model of tropospheric chemistry is used to investigate the changes in tropospheric O3 and OH since preindustrial times as a result of fuel combustion and industry, biomass burning, and growth in atmospheric CH4. Model results indicate a 63% increase of the global tropospheric O3 burden from preindustrial times to present (80% and 50% in the northern and southern hemispheres, respectively). Anthropogenic emissions of NOx and of CO and hydrocarbons make comparable contributions to the global O3 increase (60% and 40% respectively), even though the local rate of tropospheric O3 production is generally NOχ limited. The rise in O3 production parallels closely the rise in the emissions of CO and hydrocarbon because the O3 yield per mole of CO or hydrocarbon oxidized has remained constant at 0.7-0.8 mol/mol since preindustrial times. In contrast, the O3 production efficiency per mole of NOχ emitted has decreased globally by a factor of 2. We find a 9% decrease in the global mean OH concentration (mass-weighted) since preindustrial times. A linear relationship is found in the model between the global mean OH concentration and the SN/SC3/2 ratio, where SN and SC are the sources of NOχ and of CO and hydrocarbons, respectively. The relative constancy of the global mean OH concentration since preindustrial times reflects the conservation of the SN/SC3/2 ratio despite large increases in both SN and SC. Comparisons of model results with reconstructed nineteenth century observations of O3 at continental sites indicate a systematic overestimate of about 5 ppbv. Correcting this overestimate would require either a large missing chemical sink for O3 or a downward revision of the natural NOχ source from lightning (3 Tg N yr-1 in our model). The nineteenth century observations of O3 over France show no vertical gradient between the boundary layer and the free troposphere, which is inconsistent with our current understanding of tropospheric O3. The model

  11. Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Emili, E.; Barret, B.; Massart, S.; Le Flochmoen, E.; Piacentini, A.; El Amraoui, L.; Pannekoucke, O.; Cariolle, D.

    2014-01-01

    Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. We consider a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE) in combination with a linear ozone chemistry scheme to examine the impact of assimilating observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI). The assimilation of the two instruments is performed by means of a variational algorithm (4D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozonesonde measurements to verify the presence of observations and model biases. Furthermore, a longer analysis of 6 months (July-December 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (root mean square error, RMSE) of the modeled ozone columns from 30 to 15% in the upper troposphere/lower stratosphere (UTLS, 70-225 hPa). The assimilation of IASI tropospheric ozone observations (1000-225 hPa columns, TOC - tropospheric O3 column) decreases the RMSE of the model from 40 to 20% in the tropics (30° S-30° N), whereas it is not effective at higher latitudes. Results are confirmed by a comparison with additional ozone data sets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be insensitive to the assimilation parameters. We conclude that the combination of a simplified ozone chemistry scheme with frequent satellite observations is a valuable tool for the long-term analysis of stratospheric and free-tropospheric ozone.

  12. Impact of Surface Emissions to the Zonal Variability of Tropical Tropospheric Ozone and Carbon Monoxide for November 2004

    NASA Technical Reports Server (NTRS)

    Bowman, K. W.; Jones, D.; Logan, J.; Worden, H.; Boersma, F.; Chang, R.; Kulawik, S.; Osterman, G.; Worden, J.

    2008-01-01

    The chemical and dynamical processes governing the zonal variability of tropical tropospheric ozone and carbon monoxide are investigated for November 2004 using satellite observations, in-situ measurements, and chemical transport models in conjunction with inverse-estimated surface emissions. Vertical ozone profile estimates from the Tropospheric Emission Spectrometer (TES) and ozone sonde measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network show the so called zonal 'wave-one' pattern, which is characterized by peak ozone concentrations (70-80 ppb) centered over the Atlantic, as well as elevated concentrations of ozone over Indonesia and Australia (60-70 ppb) in the lower troposphere. Observational evidence from TES CO vertical profiles and Ozone Monitoring Instrument (OMI) NO2 columns point to regional surface emissions as an important contributor to the elevated ozone over Indonesia. This contribution is investigated with the GEOS-Chem chemistry and transport model using surface emission estimates derived from an optimal inverse model, which was constrained by TES and Measurements Of Pollution In The Troposphere (MOPITT) CO profiles (Jones et al., 2007). These a posteriori estimates, which were over a factor of 2 greater than climatological emissions, reduced differences between GEOS-Chem and TES ozone observations by 30-40% and led to changes in GEOS-Chem upper tropospheric ozone of up to 40% over Indonesia. The remaining residual differences can be explained in part by upper tropospheric ozone produced from lightning NOx in the South Atlantic. Furthermore, model simulations from GEOS-Chem indicate that ozone over Indonesian/Australian is more sensitive to changes in surface emissions of NOx than ozone over the tropical Atlantic.

  13. Analysis of the effectiveness of the NEC Directive on the tropospheric ozone levels in Portugal

    NASA Astrophysics Data System (ADS)

    Barros, N.; Fontes, T.; Silva, M. P.; Manso, M. C.; Carvalho, A. C.

    2015-04-01

    The National Emission Ceilings Directive 2001/81/CE (NEC Directive) was adopted in the European Community in 2001 and went through a revision process in 2005. One of its main objectives is to improve the protection of the environment and human health against the risks of adverse effects from ground-level ozone, moving towards the long-term objective of not exceeding critical levels proved to effectively protect the populations and ecosystems. Considering such objectives, national emission ceilings were established imposing the years 2010 and 2020 as benchmarks. Ten years later, what was the effectiveness of this Directive concerning the control of tropospheric ozone levels in Portugal? In order to answer the previous question, annual ozone precursors' emissions (NOx, NMVOC) and annual atmospheric concentrations (NOx and O3) were analyzed between 1990 and 2011. The background concentrations were assessed in each environment type of air quality station (urban, suburban and rural) through their annual mean ozone concentration and the hourly information threshold exceedances (episodic peak levels). To evaluate the statistical differences in the inter-annual episodic peak levels, a Peak Ozone Index (POIx) was defined and calculated. The results show that, despite the achievement on the emissions NEC Directive goals, associated to the reduction of ozone precursors' emissions, and the decrease of ozone episodic peak levels, the mean tropospheric ozone concentrations significantly increased between 2003 and 2007 (p < 0.05) although the number of exceedances to the information threshold (180 μg m-3) has decreased. During the period of 1990-2000, before the implementation of the NEC Directive, the mean ozone values were 25% lower in rural stations, 26% in urban stations and 12% in suburban stations, demonstrating that the NEC policy based on NOx and NMVOCs emissions reduction does not lead to an effective overall reduction of ozone concentrations considering the reduction

  14. Signature of tropospheric ozone and nitrogen dioxide from space: A case study for Athens, Greece

    NASA Astrophysics Data System (ADS)

    Varotsos, C.; Christodoulakis, J.; Tzanis, C.; Cracknell, A. P.

    2014-06-01

    The aim of the present study is to investigate the variability of the tropospheric ozone and nitrogen dioxide (NO2) columns over mainland Greece, by using observations carried out by satellite-borne instrumentation and Multi Sensor Reanalysis. The results obtained show that the tropospheric ozone residual (TOR) dispersed farther away than the tropospheric NO2 column (TNO), due to the longer TOR's lifetime in respect to that of TNO. This results in the influence of the air quality of the nearby southern islands from the air pollution of the greater Athens basin. Furthermore, the TOR and TNO columns over Athens, for the period October 2004 to December 2011 were found to be negatively correlated with a correlation coefficient -0.85, in contrast to recent findings which suggested strong positive correlation. Interestingly, this strong negative correlation into a slight positive correlation when the TNO concentration becomes higher than around 4 × 1015 molec cm-2, thus being best fitted by a quadratic relationship. In addition, the temporal evolution of TOR during 1979-1993 showed a decline of 0.2% per decade and just after 1993 it seems to obey a positive trend of 0.1% per decade, thus recovering during the period 1993-2011 almost 63% of the lost TOR amounts through the years 1979-1993. Finally, the association between TOR, the total ozone column (TOZ), the tropopause height and the outgoing longwave radiation (OLR) is presented by analysing observations during 1979-2011. An unexpected positive correlation between OLR and TOR was found, which may probably be attributed to the fact that enhanced abundance in tropospheric water vapor reduces the summertime TOR maximum by destructing ozone in the lower and middle troposphere through uptake mechanisms, thus emitting higher amounts of longwave radiation upwards.

  15. Photochemical production of ozone in the upper troposphere in association with cumulus convection over Indonesia

    NASA Astrophysics Data System (ADS)

    Kita, K.; Kawakami, S.; Miyazaki, Y.; Higashi, Y.; Kondo, Y.; Nishi, N.; Koike, M.; Blake, D. R.; Machida, T.; Sano, T.; Hu, W.; Ko, M.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment phase A (BIBLE-A) aircraft observation campaign was conducted from 24 September to 10 October 1998, during a La Niña period. During this campaign, distributions of ozone and its precursors (NO, CO, and nonmethane hydrocarbons (NMHCs)) were observed over the tropical Pacific Ocean, Indonesia, and northern Australia. Mixing ratios of ozone and its precursors were very low at altitudes between 0 and 13.5 km over the tropical Pacific Ocean. The mixing ratios of ozone precursors above 8 km over Indonesia were often significantly higher than those over the tropical Pacific Ocean, even though the prevailing easterlies carried the air from the tropical Pacific Ocean to over Indonesia within several days. For example, median NO and CO mixing ratios in the upper troposphere were 12 parts per trillion (pptv) and 72 parts per billion (ppbv) over the tropical Pacific Ocean and were 83 pptv and 85 ppbv over western Indonesia, respectively. Meteorological analyses and high ethene (C2H4) mixing ratios indicate that the increase of the ozone precursors was caused by active convection over Indonesia through upward transport of polluted air, mixing, and lightning all within the few days prior to observation. Sources of ozone precursors are discussed by comparing correlations of some NMHCs and CH3Cl concentrations with CO between the lower and upper troposphere. Biomass burning in Indonesia was nearly inactive during BIBLE-A and was not a dominant source of the ozone precursors, but urban pollution and lightning contributed importantly to their increases. The increase in ozone precursors raised net ozone production rates over western Indonesia in the upper troposphere, as shown by a photochemical model calculation. However, the ozone mixing ratio (~20 ppbv) did not increase significantly over Indonesia because photochemical production of ozone did not have sufficient time since the augmentation of ozone precursors. Backward trajectories

  16. Photochemical production of ozone in the upper troposphere in association with cumulus convection over Indonesia

    NASA Astrophysics Data System (ADS)

    Kita, K.; Kawakami, S.; Miyazaki, Y.; Higashi, Y.; Kondo, Y.; Nishi, N.; Koike, M.; Blake, D. R.; Machida, T.; Sano, T.; Hu, W.; Ko, M.; Ogawa, T.

    2002-02-01

    The Biomass Burning and Lightning Experiment phase A (BIBLE-A) aircraft observation campaign was conducted from 24 September to 10 October 1998, during a La Niña period. During this campaign, distributions of ozone and its precursors (NO, CO, and nonmethane hydrocarbons (NMHCs)) were observed over the tropical Pacific Ocean, Indonesia, and northern Australia. Mixing ratios of ozone and its precursors were very low at altitudes between 0 and 13.5 km over the tropical Pacific Ocean. The mixing ratios of ozone precursors above 8 km over Indonesia were often significantly higher than those over the tropical Pacific Ocean, even though the prevailing easterlies carried the air from the tropical Pacific Ocean to over Indonesia within several days. For example, median NO and CO mixing ratios in the upper troposphere were 12 parts per trillion (pptv) and 72 parts per billion (ppbv) over the tropical Pacific Ocean and were 83 pptv and 85 ppbv over western Indonesia, respectively. Meteorological analyses and high ethene (C2H4) mixing ratios indicate that the increase of the ozone precursors was caused by active convection over Indonesia through upward transport of polluted air, mixing, and lightning all within the few days prior to observation. Sources of ozone precursors are discussed by comparing correlations of some NMHCs and CH3Cl concentrations with CO between the lower and upper troposphere. Biomass burning in Indonesia was nearly inactive during BIBLE-A and was not a dominant source of the ozone precursors, but urban pollution and lightning contributed importantly to their increases. The increase in ozone precursors raised net ozone production rates over western Indonesia in the upper troposphere, as shown by a photochemical model calculation. However, the ozone mixing ratio (˜20 ppbv) did not increase significantly over Indonesia because photochemical production of ozone did not have sufficient time since the augmentation of ozone precursors. Backward trajectories

  17. Tropospheric ozone measurements at the equatorial region (1980-1988)

    NASA Technical Reports Server (NTRS)

    Ilyas, Mohammad

    1994-01-01

    Results from surface ozone measurements at Penang (5.5 deg N, 100 deg E) over 1980-88 period are presented. The study indicates the ozone concentrations undergoing significant diurnal and seasonal variations. The peak concentration are observed at around mid-day (up to 35 nb) but the O3 concentration generally drops to zero level in the early evening and remains unchanged until mid-morning. Monthly-averaged daily 1-h average concentrations are generally small (4-13 nb) and decrease continually from the early part of the year to the end. Frequently, varying local weather conditions seem to influence the O3 concentrations.

  18. Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

    NASA Astrophysics Data System (ADS)

    Yan, Yingying; Lin, Jintai; Chen, Jinxuan; Hu, Lu

    2016-02-01

    Small-scale nonlinear chemical and physical processes over pollution source regions affect the tropospheric ozone (O3), but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100-500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use the recently built two-way coupling system of the GEOS-Chem CTM to simulate the regional and global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Specifically, the nested models take lateral boundary conditions (LBCs) from the global model, better capture small-scale processes and feed back to modify the global model simulation within the nested domains, with a subsequent effect on their LBCs. Compared to the global model alone, the two-way coupled system better simulates the tropospheric O3 both within and outside the nested domains, as found by evaluation against a suite of ground (1420 sites from the World Data Centre for Greenhouse Gases (WDCGG), the United States National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory Global Monitoring Division (GMD), the Chemical Coordination Centre of European Monitoring and Evaluation Programme (EMEP), and the United States Environmental Protection Agency Air Quality System (AQS)), aircraft (the High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) and Measurement of Ozone and Water Vapor by Airbus In- Service Aircraft (MOZAIC)) and satellite measurements (two Ozone Monitoring Instrument (OMI) products). The two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean surface O3 with the ground measurements

  19. Extreme value modeling for the analysis and prediction of time series of extreme tropospheric ozone levels: a case study.

    PubMed

    Escarela, Gabriel

    2012-06-01

    The occurrence of high concentrations of tropospheric ozone is considered as one of the most important issues of air management programs. The prediction of dangerous ozone levels for the public health and the environment, along with the assessment of air quality control programs aimed at reducing their severity, is of considerable interest to the scientific community and to policy makers. The chemical mechanisms of tropospheric ozone formation are complex, and highly variable meteorological conditions contribute additionally to difficulties in accurate study and prediction of high levels of ozone. Statistical methods offer an effective approach to understand the problem and eventually improve the ability to predict maximum levels of ozone. In this paper an extreme value model is developed to study data sets that consist of periodically collected maxima of tropospheric ozone concentrations and meteorological variables. The methods are applied to daily tropospheric ozone maxima in Guadalajara City, Mexico, for the period January 1997 to December 2006. The model adjusts the daily rate of change in ozone for concurrent impacts of seasonality and present and past meteorological conditions, which include surface temperature, wind speed, wind direction, relative humidity, and ozone. The results indicate that trend, annual effects, and key meteorological variables along with some interactions explain the variation in daily ozone maxima. Prediction performance assessments yield reasonably good results. PMID:22788103

  20. Introduction to working group on tropospheric ozone, Health Effects Institute environmental epidemiology planning project.

    PubMed Central

    Tager, I B

    1993-01-01

    The working group on tropospheric ozone of the Health Effects Institute has evaluated the need for epidemiologic studies on the health effects of ozone (O3) exposure. This paper summarizes current data and identifies possible research questions. The extent to which ozone exposure results in chronic health effects is largely undefined and is the central issue for epidemiologic studies. Most current data focus on transient endpoints; the link between acute changes in symptoms and/or lung function and possible chronic effects has not been established. Concepts of ozone-induced health effects have been extended to include processes of chronic disease (e.g., markers of ongoing inflammation and repair, markers of accelerated lung aging). Traditional epidemiologic studies performed have focused only on accelerated lung aging and are limited by a number of methodologic problems. Recent, very preliminary, studies suggest new opportunities for the use of human lung tissue and a variety biological response markers as part of epidemiologic studies. The identification of sensitive subpopulations with regard to ozone-induced health effects has been studied incompletely and is important both in terms of study efficiency and mechanistic insight. Methodologic advances in the reconstruction of past ozone exposure are seen as essential, as is the incorporation of emerging markers of biologic response to ozone into traditional epidemiologic study designs. Finally, more data on the joint and independent contribution of other ambient air pollutants to putative ozone-induced health effects is warranted. PMID:8206032

  1. The reservoir of ozone in the boundary layer of the eastern United States and its potential impact on the global tropospheric ozone budget

    NASA Technical Reports Server (NTRS)

    Vukovich, F. M.; Fishman, J.; Browell, E. V.

    1985-01-01

    An analysis of available ozone data in the eastern two-thirds of the United States indicates that a substantial reservoir of ozone is present in the summertime. Five-year mean concentrations range from 40 to 65 ppbv. The reservoir covered an area of several million square kilometers and extends vertically from the surface to 1 to 2 km. The vertical distribution of ozone in the reservoir during midday supports a transport of additional ozone from the boundary layer to the free troposphere. Data are presented demonstrating the potential effect of transport by convective clouds and by the sea breeze circulation - mechanisms by which ozone may be transported out of the boundary layer into the free troposphere. The potential impact of this reservoir on the tropospheric ozone budget is discussed. It is shown that if less than half of the ozone mass in this reservoir is transported to the free troposphere, then the amount of ozone transported out of the boundary layer approximates the amount of ozone transported downward during a tropopause fold event.

  2. Diagnosing the stratosphere-to-troposphere flux of ozone in a chemistry transport model

    NASA Astrophysics Data System (ADS)

    Hsu, Juno; Prather, Michael J.; Wild, Oliver

    2005-10-01

    Events involving stratosphere-troposphere exchange (STE) of ozone, such as tropopause folds and westerly ducts, are readily identified in observations and models, but a quantitative flux specifying where and when stratospheric ozone is mixed into the troposphere is not readily discerned from either. This work presents a new diagnostic based on determining when stratospheric air is mixed and diluted down to tropospheric abundances (<100 ppb) and hence effectively participates in tropospheric chemistry. The method is applied to two years of high-resolution, global meteorological fields (1.9 degrees, 40 levels) from the ECMWF forecast model derived by U. Oslo for chemistry transport modeling and used in TRACE-P studies. The UCI CTM is run here with linearized stratospheric ozone chemistry (Linoz) and a parameterized tropospheric sink. In terms of events, the CTM accurately follows a March 2001 westerly duct stratospheric intrusion into the tropical eastern Pacific as observed by TOMS and calculates a 48-hour burst of STE O3 flux for that region. The influx associated with the event (0.3 Tg) is much less than the anomalous amount seen as an isolated island in column ozone (1.7 Tg). A climatology of monthly mean STE fluxes is similar for both years (January to December 1997 and May 2000 to April 2001), but the warm phase of ENSO December 1997 is distinctly different from the cold phase of ENSO month December 2000. Global ozone fluxes are about 515 Tg (year 1997) and 550 Tg (year 2000/2001) with an equal amount into each hemisphere, and larger springtime fluxes for both hemispheres. In terms of geographical distribution, Northern Hemisphere regions of high ozone flux follow the jet streams over the oceans in the winter and over the continents in the summer, in agreement with many previous studies. In contrast, we find the largest STE flux is located in the subtropics during late spring, particularly over the Tibetan Plateau in May. This hot spot of STE is not a numerical

  3. PREDICTING THE IMPACT OF TROPOSPHERIC OZONE ON PLANTS AND ECOSYSTEMS AS A BASIS FOR SETTING NATIONAL AIR QUALITY STANDARDS

    EPA Science Inventory

    The Clean Air Act provides for establishing National Ambient Air Quality Standards (NAAQS) to protect public welfare (including crops, forests, ecosystems, and soils) from adverse effects of air pollutants, including tropospheric ozone. The formulation of policies is science-base...

  4. Tropospheric Vertical Distribution of Tropical Atlantic Ozone Observed by TES during the Northern African Biomass Burning Season

    NASA Technical Reports Server (NTRS)

    Jourdain, L.; Worden, H. M.; Worden, J. R.; Bowman, K.; Li, Q.; Eldering, A.; Kulawik, S. S.; Osterman, G.; Boersma, K. F.; Fisher, B.; Rinsland, C. P.; Beer, R.; Gunson, M.

    2007-01-01

    We present vertical distributions of ozone from the Tropospheric Emission Spectrometer (TES) over the tropical Atlantic Ocean during January 2005. Between 10N and 20S, TES ozone retrievals have Degrees of Freedom for signal (DOF) around 0.7 - 0.8 each for tropospheric altitudes above and below 500 hPa. As a result, TES is able to capture for the first time from space a distribution characterized by two maxima: one in the lower troposphere north of the ITCZ and one in the middle and upper troposphere south of the ITCZ. We focus our analysis on the north tropical Atlantic Ocean, where most of previous satellite observations showed discrepancies with in-situ ozone observations and models. Trajectory analyses and a sensitivity study using the GEOS-Chem model confirm the influence of northern Africa biomass burning on the elevated ozone mixing ratios observed by TES over this region.

  5. Environmental auditing: An approach for characterizing tropospheric ozone risk to forests

    SciTech Connect

    Hogsett, W.E.; Weber, J.E.; Tingey, D.; Herstrom, A.; Lee, E.H.; Laurence, J.A.

    1997-01-01

    The risk tropospheric ozone poses to forests in the United States dependents on the variation in ozone exposure across the forests and the various environmental and climate factors predominant in the region. All these factors have a spatial nature; an approach to characterization of ozone risk is presented that places ozone exposure-response functions for species as seedlings and model-simulated tree and stand responses in a spatial context using a geographical information systems (GIS). The GIS is used to aggregate factors considered important in a risk characterization: (1) estimated ozone exposures over forested regions, (2) measures of ozone effects on species` and stand growth, and (3) spatially distributed environmental, genetic, and exposure influences on species` response to ozone. The GIS-based risk characterization provides an estimation the extent and magnitude of the potential ozone impact on forests. A preliminary risk characterization demonstrating this considered only the eastern United States and only the limited empirical data quantifying the effect of ozone exposures on forest tree species as seedlings. The area-weighted response of the annual seedling biomass loss formed the basis for a sensitivity ranking: sensitive-aspen and black cherry (14%-33% biomass loss over 50% of their distribution); moderately sensitive-tulip popular, loblolly pine, eastern white pine, and sugar maple (5%-13% biomass loss); insensitive-Virginia pine and red maple (0%-1% loss). Future GIS-based risk characterizations will include process-based model simulations of the three- to 5-year growth response of individual species as large trees. The interactive nature of GIS provides a tool to explore consequences of the range of climate conditions across a species` distribution, forest management practices, changing ozone precursors, regulatory control strategies, and other factors influencing the spatial distribution of ozone over time. 43 refs., 11 figs., 3 tabs.

  6. Modelled and observed vertical ozone distribution in the troposphere over Europe

    NASA Astrophysics Data System (ADS)

    Struzewska, Joanna; Kaminski, Jacek W.; Szymankiewicz, Karol

    2016-04-01

    Air Quality models are usually validated against surface measurements of air pollutants concentrations. Some validation of the vertical structure of the modelled atmosphere in terms of the distribution and stratification of trace gases concentrations is limited to the boundary layer. We will focus on problems that face air quality models with reproducing the ozone profile in the troposphere that can be connected with an insufficient representation of stratospheric-tropospheric exchange due to with too low model top as well as to an inappropriate top boundary conditions. We will present the climatology of ozone vertical profiles in different locations across Europe based on the GEM-AQ model (Kaminski et al., 2008) calculation for the period 2008-2010. The core of the model domain covered the European continent with the resolution of 0.125 deg. Modelling results will be compared with ozone soundings from available stations. Seasonal variability of the observed and modelled ozone profiles will be discussed. Also, variability patterns will be compared for different regions of Europe. An attempt will be made to correlate the bias of the ozone profile in the ABL with NO2 column bias in corresponding locations.

  7. Large-scale circulation patterns associated with high concentrations of tropospheric ozone in the tropical South Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Fakhruzzaman, K. M.; Fishman, J.; Brackett, V. G.; Kendall, J. D.; Justice, C. O.

    1994-01-01

    Several years of satellite observations indicate the presence of enhanced amounts of tropospheric ozone over the tropical South Atlantic during the austral springs. Wide-spread biomass burning is prevalent over Africa and South America during the same time of the year. Another recent satellite technique has identified the locations of fires over the continents. In this study, we present an analysis of the prevailing meteorological conditions when the highest amounts of tropospheric ozone are present.

  8. Analysis and Comparison of Raw and Weather-corrected July Mean Ozone, Satellite-derived Tropospheric NO2 and Ozone, and Indicator Ratios from Space for the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Reddy, P. J.; Tonnesen, G.

    2012-12-01

    In order to evaluate the efficacy of emissions control strategies for reduction of ground-level ozone concentrations, it is important to determine how ozone sensitivity to NOx and VOC varies in space and time across a region. The Denver Non-attainment Area for ozone has several monitoring sites that exceed the National Ambient Air Quality Standard for eight-hour ozone concentrations. Aside from emissions, weather is a major factor that affects year-to-year variations in surface ozone. For Colorado's Front Range region, it has been found that much of the year-to-year variance in the surface ozone concentration data can be explained by the effects of upper-level high pressure strength. Local July mean 500-millibar heights account for more than fifty percent of the year-to-year variation in July mean daily maximum eight-hour ozone concentrations for most sites. We compare tropospheric column ozone data from the NASA OMI/MLS with patterns of 500-millibar heights across the Western U.S. and surface ozone data. This comparison highlights the role of the Four Corners high in years with increased accumulation of local or regional background ozone. We also compare trends in weather-corrected ozone with mean tropospheric NO2 from the OMI and GOME 2 retrievals and explore statistical relationships between ground-level and satellite measurements for the period from 2005 through 2012. These analyses provide clues about the responses of ground-level ozone to meteorology and climate and the significant real-world changes in tropospheric NO2 that occurred during the period. Finally, we analyze ratios of satellite-derived formaldehyde to NO2 and compare these with the results of process analyses of VOC and NOx sensitivity from photochemical modeling of a specific ozone episode in July 2006. Taken together, this work can serve as a weight-of-evidence analysis for State Implementation Plan ozone model attainment demonstrations and help to constrain estimates of ozone responses to

  9. A Multi-sensor Upper Tropospheric Ozone Product (MUTOP) based on TES ozone and GOES water vapor: validation with ozonesondes

    NASA Astrophysics Data System (ADS)

    Moody, J. L.; Felker, S. R.; Wimmers, A. J.; Osterman, G.; Bowman, K.; Thompson, A. M.; Tarasick, D. W.

    2011-11-01

    Accurate representation of ozone in the extratropical upper troposphere (UT) remains a challenge. However, the implementation of hyper-spectral remote sensing using satellite instruments such as the Tropospheric Emission Spectrometer (TES) provides an avenue for mapping ozone in this region, from 500 to 300 hPa. As a polar orbiting satellite TES observations are limited, but in this paper they are combined with geostationary satellite observations of water vapor. This paper describes a validation of the Multi-sensor UT Ozone Product (MUTOP). MUTOP is statistical retrieval method, a derived product image based on the correlation of two remotely sensed quantities, TES ozone, against geostationary (GOES) specific humidity and modeled potential vorticity, a dynamical tracer in the UT. These TES-derived UT ozone mixing ratios are compared to coincident ozonesonde measurements of layer-average UT ozone mixing ratios made during the NASA INTEX/B field campaign in the spring of 2006; the region for this study is effectively the GOES west domain covering the Eastern North Pacific Ocean and the Western United States. This intercomparison evaluates MUTOP skill at representing ozone magnitude and variability in this region of complex dynamics. In total, 11 ozonesonde launch sites were available for this study, providing 127 individual sondes for comparison; the overall mean ozone of the 500-300 hPa layer for these sondes was 78.0 ppbv. MUTOP reproduces in-situ measurements reasonably well, producing an UT mean of 82.3 ppbv, with a mean absolute error of 12.2 ppbv and a root mean square error of 16.4 ppbv relative to ozonesondes across all sites. An overall UT mean bias of 4.3 ppbv relative to sondes was determined for MUTOP. Considered in the context of past TES validation studies, these results illustrate that MUTOP is able to maintain accuracy similar to TES while expanding coverage to the entire GOES-West satellite domain. In addition MUTOP provides six-hour temporal

  10. A multi-sensor upper tropospheric ozone product (MUTOP) based on TES ozone and GOES water vapor: validation with ozonesondes

    NASA Astrophysics Data System (ADS)

    Moody, J. L.; Felker, S. R.; Wimmers, A. J.; Osterman, G.; Bowman, K.; Thompson, A. M.; Tarasick, D. W.

    2012-06-01

    Accurate representation of ozone in the extratropical upper troposphere (UT) remains a challenge. However, the implementation of hyper-spectral remote sensing using satellite instruments such as the Tropospheric Emission Spectrometer (TES) provides an avenue for mapping ozone in this region, from 500 to 300 hPa. As a polar orbiting satellite TES observations are limited, but in this paper they are combined with geostationary satellite observations of water vapor. This paper describes a validation of the Multi-sensor UT Ozone Product (MUTOP). MUTOP, based on a statistical retrieval method, is an image product derived from the multiple regression of remotely sensed TES ozone, against geostationary (GOES) specific humidity (remotely sensed) and potential vorticity (a modeled dynamical tracer in the UT). These TES-derived UT ozone mixing ratios are compared to coincident ozonesonde measurements of layer-average UT ozone mixing ratios made during the NASA INTEX/B field campaign in the spring of 2006; the region for this study is effectively the GOES west domain covering the eastern North Pacific Ocean and the western United States. This intercomparison evaluates MUTOP skill at representing ozone magnitude and variability in this region of complex dynamics. In total, 11 ozonesonde launch sites were available for this study, providing 127 individual sondes for comparison; the overall mean ozone of the 500-300 hPa layer for these sondes was 78.0 ppbv. MUTOP reproduces in~situ measurements reasonably well, producing an UT mean of 82.3 ppbv, with a mean absolute error of 12.2 ppbv and a root mean square error of 16.4 ppbv relative to ozonesondes across all sites. An overall UT mean bias of 4.3 ppbv relative to sondes was determined for MUTOP. Considered in the context of past TES validation studies, these results illustrate that MUTOP is able to maintain accuracy similar to TES while expanding coverage to the entire GOES-West satellite domain. In addition MUTOP provides six

  11. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-04-01

    A regional air quality simulation framework including the Weather Research and Forecasting modelling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitorings, ozone zondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around north eastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  12. Differential Absorption Lidar to Measure Sub-Hourly Variation of Tropospheric Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephanie

    2009-01-01

    A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by the University of Alabama at Huntsville and NASA, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min temporal integration

  13. The possible influences of the increasing anthropogenic emissions in India on tropospheric ozone and OH

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Li, Weiliang; Zhou, Xiuji; Isaksen, I. S. A.; Sundet, J. K.; He, Jinhai

    2003-11-01

    A 3-D chemical transport model (OSLO CTM2) is used to investigate the influences of the increasing anthropogenic emission in India. The model is capable of reproducing the observational results of the INDOEX experiment and the measurements in summer over India well. The model results show that when NO x and CO emissions in India are doubled, ozone concentration increases, and global average OH decreases a little. Under the effects of the Indian summer monsoon, NO x and CO in India are efficiently transported into the middle and upper troposphere by the upward current and the convective activities so that the NO x , CO, and ozone in the middle and upper troposphere significantly increase with the increasing NO x and CO emissions. These increases extensively influence a part of Asia, Africa, and Europe, and persist from June to September.

  14. Differential Absorption Lidar to Measure Subhourly Variation of Tropospheric Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephania

    2011-01-01

    A tropospheric ozone Differential Absorption Lidar system, developed jointly by The University of Alabama in Huntsville and the National Aeronautics and Space Administration, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min 17 temporal integration.

  15. Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl

    SciTech Connect

    Atherton, C S; Bergmann, D J; Marcy, T P; Fahey, D W; Gao, R S; Popp, P J; Richard, E C; Thompson, T L; Rosenlof, K H; Ray, E A; Salawitch, R J; Ridley, B A; . Weinheimer, A J; Loewenstein, M; Weinstock, E M; Mahoney, M J

    2004-03-08

    A chemical ionization mass spectrometry (CIMS) technique has been developed for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) are often near or below the 0.005-ppbv detection limit of the measurements, indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels as a result of stratosphere-to-troposphere transport events. A method for diagnosing the amount of stratospheric ozone in these UT parcels was developed using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.

  16. Interpretation of TOMS Observations of Tropical Tropospheric Ozone with a Global Model and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Martin, Randall V.; Jacob, Daniel J.; Logan, Jennifer A.; Bey, Isabelle; Yantosca, Robert M.; Staudt, Amanda C.; Fiore, Arlene M.; Duncan, Bryan N.; Liu, Hongyu; Ginoux, Paul

    2004-01-01

    We interpret the distribution of tropical tropospheric ozone columns (TTOCs) from the Total Ozone Mapping Spectrometer (TOMS) by using a global three-dimensional model of tropospheric chemistry (GEOS-CHEM) and additional information from in situ observations. The GEOS-CHEM TTOCs capture 44% of the variance of monthly mean TOMS TTOCs from the convective cloud differential method (CCD) with no global bias. Major discrepancies are found over northern Africa and south Asia where the TOMS TTOCs do not capture the seasonal enhancements from biomass burning found in the model and in aircraft observations. A characteristic feature of these northern topical enhancements, in contrast to southern tropical enhancements, is that they are driven by the lower troposphere where the sensitivity of TOMS is poor due to Rayleigh scattering. We develop an efficiency correction to the TOMS retrieval algorithm that accounts for the variability of ozone in the lower troposphere. This efficiency correction increases TTOC's over biomass burning regions by 3-5 Dobson units (DU) and decreases them by 2-5 DU over oceanic regions, improving the agreement between CCD TTOCs and in situ observations. Applying the correction to CCD TTOCs reduces by approximately DU the magnitude of the "tropical Atlantic paradox" [Thompson et al, 2000], i.e. the presence of a TTOC enhancement over the southern tropical Atlantic during the northern African biomass burning season in December-February. We reproduce the remainder of the paradox in the model and explain it by the combination of upper tropospheric ozone production from lightning NOx, peristent subsidence over the southern tropical Atlantic as part of the Walker circulation, and cross-equatorial transport of upper tropospheric ozone from northern midlatitudes in the African "westerly duct." These processes in the model can also account for the observed 13-17 DU persistent wave-1 pattern in TTOCs with a maximum above the tropical Atlantic and a minimum

  17. Tropospheric Ozone Near-Nadir-Viewing IR Spectral Sensitivity and Ozone Measurements from NAST-I

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Smith, William L.; Larar, Allen M.

    2001-01-01

    Infrared ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) from the NASA ER-2 aircraft (approximately 20 km altitude) with a spectral resolution of 0.25/cm were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented.

  18. Dial Measurements of Free-Tropospheric Ozone Profiles in Huntsville, AL

    NASA Technical Reports Server (NTRS)

    Newchurch, Mike; Kuang, Shi; Burris, John; Johnson, Steve; Long, Stephanie

    2008-01-01

    A tropospheric ozone DIfferential Absorption Lidar (DIAL) system has been developed jointly by NASA and the University of Alabama at Huntsville (UAH). Two separated Nd:YAG pumped dye laser systems produce the laser pulses with wavelengths of 285 and 291 nm at 20 Hz frequency. The receiver is a Newtonian telescope with a 40 cm primary and a two-channel aft optics unit. The detection system currently uses photon counting to facilitate operations at the maximum achievable altitude. This lidar measures free-tropospheric ozone profiles between 4-10 km at Regional Atmospheric Profiling Laboratory for Discovery (RAPCD) in UAH campus (ASL 206 m) under both daytime and nighttime conditions. Frequent coincident ozonesonde flights and theoretical calculations provide evidence to indicate the retrieval accuracy ranges from approx.5% at 4 km to approx.60% at 10 km with 750-m vertical resolution and 30-minute integration. Three Hamamatsu 7400 PMTs and analog detection technique will be added on the current system to extend the measurement to approx.100 m above ground to monitor the PBL and lower tropospheric ozone variations.

  19. The impact of greenhouse gases on past changes in tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Lang, C.; Waugh, D. W.; Olsen, M. A.; Douglass, A. R.; Liang, Q.; Nielsen, J. E.; Oman, L. D.; Pawson, S.; Stolarski, R. S.

    2012-12-01

    The impact of changes in the abundance of greenhouse gases (GHGs) on the evolution of tropospheric ozone (O3) between 1960 and 2005 is examined using a version of the Goddard Earth Observing System chemistry-climate model (GEOS CCM) with a combined troposphere-stratosphere chemical mechanism. Simulations are performed to isolate the relative role of increases in methane (CH4) and stratospheric ozone depleting substances (ODSs) on tropospheric O3. The 1960 to 2005 increases in GHGs (CO2, N2O, CH4, and ODSs) cause increases of around 1-8% in zonal-mean tropospheric O3 in the tropics and northern extratropics, but decreases of 2-4% in most of the southern extratropics. These O3 changes are due primarily to increases in CH4 and ODSs, which cause changes of comparable magnitude but opposite sign. The CH4-related increases in O3are similar in each hemisphere (˜6%), but the ODS-related decreases in the southern extratropics are much larger than in northern extratropics (10% compared to 2%). This results in an interhemispheric difference in the sign of past O3 change. Increases in the other GHGs (CO2 and N2O) and SSTs have only a small impact on the total burden over this period, but do cause zonal variations in the sign of changes in tropical O3 that are coupled to changes in vertical velocities and water vapor.

  20. Sources of uncertainty in stand-level predictions of forest response to tropospheric ozone

    SciTech Connect

    Smith, J.E.; Woodbury, P.B.; Laurence, J.A.

    1995-09-01

    We present a simple model to analyze uncertainty in predicted effects of tropospheric ozone on loblolly pine stands in southeastern USA. Assessment of pollution stress on an ecosystem requires the intergration of many, possibly disparate, datasets to produce a quality-estimate of the information provided for resource management and policy formulation. We are developing procedures to identify and quantify sources of uncertainty in a simple, flexible modeling context. We incorporated published data from experimental, observational, and modeling research into the uncertainty analysis. Major sources of uncertainty arise in combining results from diverse studies and from scaling what are usually seedling data (from exposure chambers) to growth of mature trees. Our model of loblolly stand productivity explicitly states relationships among sources of uncertainty and uses Monte Carlo simulations to estimate relative influences. This approach allows researchers or analysts to examine how uncertain model predictions are affected by (1) assumptions about how system components are related and (2) acquisition of additional information through further research.

  1. Sources of Tropospheric Ozone along the Asian Pacific Rim: An Analysis of Ozonesonde Observations

    NASA Technical Reports Server (NTRS)

    Liu, Hong-Yu; Jacob, Daniel J.; Chan, Lo Yin; Oltmans, Samuel J.; Bey, Isabelle; Yantosca, Robert M.; Harris, Joyce M.; Duncan, Bryan N.; Martin, Randall V.

    2002-01-01

    The sources contributing to tropospheric ozone over the Asian Pacific Rim in different seasons are quantified by analysis of Hong Kong and Japanese ozonesonde observations with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations. Particular focus is placed on the extensive observations available from Hong Kong in 1996. In the middle-upper troposphere (MT- UT), maximum Asian pollution influence along the Pacific Rim occurs in summer, reflecting rapid convective transport of surface pollution. In the lower troposphere (LT) the season of maximum Asian pollution influence shifts to summer at midlatitudes from fall at low latitudes due to monsoonal influence. The UT ozone minimum and high variability observed over Hong Kong in winter reflects frequent tropical intrusions alternating with stratospheric intrusions. Asian biomass burning makes a major contribution to ozone at less than 32 deg.N in spring. Maximum European pollution influence (less than 5 ppbv) occurs in spring in the LT. North American pollution influence exceeds European influence in the UT-MT, reflecting the uplift from convection and the warm conveyor belts over the eastern seaboard of North America. African outflow makes a major contribution to ozone in the low-latitude MT-UT over the Pacific Rim during November- April. Lightning influence over the Pacific Rim is minimum in summer due to westward UT transport at low latitudes associated with the Tibetan anticyclone. The Asian outflow flux of ozone to the Pacific is maximum in spring and fall and includes a major contribution from Asian anthropogenic sources year-round.

  2. Development of the Double Etalon Fabry-Perot Interferometer for Determining Total and Tropospheric Ozone Concentrations

    NASA Technical Reports Server (NTRS)

    Cook, William

    1999-01-01

    Measuring and understanding the distribution of ozone through the lower levels of Earth's atmosphere are high priorities in global change and climate research. Of particular interest now is the global distribution of ozone in the upper troposphere and lower stratosphere. Global coverage of the stratospheric ozone is feasible only via remote sensing instruments on a space-based platform. And though extensive monitoring tropospheric ozone is possible using instruments flown aboard conventional aircraft, a space-based system would be significantly less costly and provide information over a much broader area and produce more uniform coverage. Here we describe the prototype of an instrument being developed to monitor, from an orbiting spacecraft, the ozone found in Earth's upper troposphere and lower stratosphere. Our new spectrometer is an infrared Fabry-Perot interferometer which uses two synchrounously tuned etalons: a high resolution narrow band device and a lower resolution broader band filtering etalon. The prototype is a scanning device making use of nearly collimated input radiation and a single element detector. As presently configured, it is capable of providing a resolution better than 0.07/cm with a spectral band width approximately 5/cm wide and centered at 1054.7/cm. For the future space-based emission device a modification of the the prototype was to be made to employ innovative circle-to-line detector optics, those developed or in development at UM/SPRL, and a focal plane array detector. These enhancements would enable a simultaneous recording of the entire spectral range of interest, but with simple detection electronics and a significant gain in signal-to-noise over that of the scanning version.

  3. Tropospheric ozone variability during the monsoon season in Malaysia

    NASA Astrophysics Data System (ADS)

    Ahamad, Fatimah; Latif, Mohd Talib

    2013-11-01

    Vertical ozone (O3) profiles obtained from ozonesondes launched at Kuala Lumpur International Airport (KLIA), Malaysia were analyzed. Results of soundings between January to March 2011 and July to September 2011 are presented along with meteorological parameters (temperature and relative humidity (RH)). The overall O3 concentration range between the soundings made during the northeast monsoon (January - March) and the southwest monsoon (July - September) were not far from each other for altitudes below 8 km. However O3 variability is less pronounced between 2 km and 12 km during the southwest monsoon compared to the northeast monsoon season.

  4. A Status Report on the SHADOZ (Southern Hemisphere Additional Ozonesondes) Project and Some Issues Affecting Ozone Climatology

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, J. C.; McPeters, R. D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    SHADOZ aims to support the study of local and global patterns in stratospheric and tropospheric ozone and to provide a data set for the validation for satellite products and model calculations of ozone. Southern hemispheric tropical ozone is of particular interest because this region appears to have complex interplay among photochemical ozone formation (from biomass burning and lightning), stratospheric dynamics, convection and possibly cross-hemispheric transport. Balloon-borne ozone instrumentation (ozonesondes), joined with standard radiosondes for measurement of pressure, temperature and relative humidity, is used to collect profiles throughout the troposphere and lower- to mid-stratosphere. A network of 10 southern hemisphere tropical and subtropical stations, called the Southern Hemisphere ADditional OZonesondes (SHADOZ) project, has been established from operational sites to assemble sonde data for 1998-2000. A status report on the archive, with station operating characteristics, will be given, along with some operational issues that may affect data analysis and interpretation.

  5. Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

    NASA Astrophysics Data System (ADS)

    Chatani, S.; Amann, M.; Goel, A.; Hao, J.; Klimont, Z.; Kumar, A.; Mishra, A.; Sharma, S.; Wang, S. X.; Wang, Y. X.; Zhao, B.

    2014-09-01

    A regional air quality simulation framework including the Weather Research and Forecasting modeling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitoring, ozonesondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implementation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around northeastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surface ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia.

  6. A New NASA Data Product: Tropospheric and Stratospheric Column Ozone in the Tropics Derived from TOMS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Chandra, S.; Bhartia, P. K.

    1999-01-01

    Tropospheric column ozone (TCO) and stratospheric column ozone (SCO) gridded data in the tropics for 1979-present are now available from NASA Goddard Space Flight Center via either direct ftp, world-NN,ide-NN,eb, or electronic mail. This note provides a brief overview of the method used to derive the data set including validation and adjustments.

  7. Southern Hemisphere Additional Ozonesondes (SHADOZ) Ozone Climatology (2005-2009): Tropospheric and Tropical Tropopause Layer (TTL) Profiles with Comparisons to Omi-based Ozone Products

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Miller, Sonya K.; Tilmes, Simone; Kollonige, Debra W.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Johnson, Brian J.; Fujiwara, Masatomo; Schmidlin, F. J.; Coetzee, G. J. R.; Komala, Ninong; Maata, Matakite; bt Mohammad, Maznorizan; Nguyo, J.; Mutai, C.; Ogino, S-Y; Da Silva, F. Raimundo; Paes Leme, N. M.; Posny, Francoise; Scheele, Rinus; Selkirk, Henry B.; Shiotani, Masato; Stubi, Rene; Levrat, Gilbert; Calpini, Bertrand; Thouret, Valerie; Tsuruta, Haruo; Canossa, Jessica Valverde; Voemel, Holger; Yonemura, S.; Andres Diaz, Jorge; Tan Thanh, Nguyen T.; Thuy Ha, Hoang T.

    2012-01-01

    We present a regional and seasonal climatology of SHADOZ ozone profiles in the troposphere and tropical tropopause layer (TTL) based on measurements taken during the first five years of Aura, 2005-2009, when new stations joined the network at Hanoi, Vietnam; Hilo, Hawaii; Alajuela Heredia, Costa Rica; Cotonou, Benin. In all, 15 stations operated during that period. A west-to-east progression of decreasing convective influence and increasing pollution leads to distinct tropospheric ozone profiles in three regions: (1) western Pacific eastern Indian Ocean; (2) equatorial Americas (San Cristobal, Alajuela, Paramaribo); (3) Atlantic and Africa. Comparisons in total ozone column from soundings, the Ozone Monitoring Instrument (OMI, on Aura, 2004-) satellite and ground-based instrumentation are presented. Most stations show better agreement with OMI than they did for EPTOMS comparisons (1998-2004; Earth-ProbeTotal Ozone Mapping Spectrometer), partly due to a revised above-burst ozone climatology. Possible station biases in the stratospheric segment of the ozone measurement noted in the first 7 years of SHADOZ ozone profiles are re-examined. High stratospheric bias observed during the TOMS period appears to persist at one station. Comparisons of SHADOZ tropospheric ozone and the daily Trajectory-enhanced Tropospheric Ozone Residual (TTOR) product (based on OMIMLS) show that the satellite-derived column amount averages 25 low. Correlations between TTOR and the SHADOZ sondes are quite good (typical r2 0.5-0.8), however, which may account for why some published residual-based OMI products capture tropospheric interannual variability fairly realistically. On the other hand, no clear explanations emerge for why TTOR-sonde discrepancies vary over a wide range at most SHADOZ sites.

  8. Elevated Ozone in the Troposphere over the Atlantic and Pacific Oceans in the Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Ziemke, J. R.; Tie, Xuexi

    2003-01-01

    Tropospheric column ozone (TCO) is derived from differential measurements of total column ozone from Nimus-7 and Earth Probe TOMS, and stratospheric column ozone from the Microwave Limb Sounder instrument on the Upper Atmospheric Research Satellite. It is shown that TCO during summer months over the Atlantic and Pacific Oceans at northern mid-latitudes is about the same (50-60 Dobson Units) as over the continents of North America, Europe and Asia, where surface emissions of nitrogen oxides from industrial sources, biomass and biofuel burning and biogenic emissions are significantly larger. This nearly uniform zonal variation in TCO is modulated by surface topography of the Rocky and Himalayan mountains and Tibetan Plateau where TCO is reduced by 20-30 Dobson Units. The zonal characteristics of TCO derived from satellite measurements are well simulated by a global chemical transport model called MOZART-2 (Model of Ozone and Related Chemical Tracers, version 2). The model results are analyzed to delineate the relative importance of various processes contributing to observed zonal characteristics of TCO, and they are shown that the surface emission of NOx contributes about 50% of the TCO at northern mid-latitudes, especially over the continents of North America, Europe and Asia. The result of TCO derived from TOMS and the analysis from MOZART-2 indicate that TCO is a very useful tool to study tropospheric O3 pollution resulting from surface emissions of pollutants.

  9. Modeling the response of mature Pinus ponderosa Laws. to tropospheric ozone: Effects of genotypic variability

    SciTech Connect

    Constable, J.V.H.; Taylor, G.E. Jr. ); Weinstein, D.A.; Laurence, J.A. )

    1994-06-01

    Regionally distributed pollutants (e.g., tropospheric ozone and CO[sub 2]) can influence the growth of terrestrial plants. The mosaic of genotypes in natural populations makes it difficult to predict the ecological consequences of pollutants throughout a species' distribution. We simulated the response of Pinus ponderosa Laws to ambient, sub-ambient and above-ambient troposopheric O[sub 3] for 3 years using TREGRO, a physiologically based three growth model. Parameters controlling growth and carbon allocation were obtained from the literature and were varied to simulate intravarietal and intervarietal genotypes (western var. Ponderosa and eastern var. Scopulorum) of Ponderosa Pine. Parameter differences between the varieties include physiology, carbon allocation and phenoloy. Ozone altered 3 year biomass gain (+6% to 61%) and fine root to leaf mass ratio ([minus]8% to [minus]14%) in spite of a small effect on photosynthesis ([<=] 10%). Overall, O[sub 3] caused growth differences between varieties to be reduced. The reduction in growth differences between genotypes due to ozone has consequences for regional identification of populations sensitive to the effects of tropospheric ozone.

  10. Tropospheric Total Ozone in the Region of the Equatorial south Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Schmidlin, Francis J.; Northam, E. Thomas; Kirchhoff, Volker W. J. H.; daSilva, Francisco Raimundo

    2000-01-01

    As a consequence of the SHADOZ effort it is possible to examine Tropospheric Total Ozone TTO, over Ascension Island (8S,14W) and compare results with similar ozone soundings for the period July 1990 through October 1992. Because of the nearly 20-year long cooperation between NASA and INPE it is possible to also compare the Ascension Island results with the long-term ozone data set available from Natal, Brazil (6S,35W). The Natal site meets requirements of the SHADOZ program. The tropopause is determined objectively using the World Meteorological Organization (WMO) criteria and the radiosonde's temperature and altitude parameters. Once tropopause heights are determined TTO can be calculated. Time-series profiles illustrate changes in TTO over the period of record.

  11. Global 3-D Modeling Studies Of Tropospheric Ozone And Related Gases

    NASA Technical Reports Server (NTRS)

    Jacob, Daniel J.; Logan, Jennifer A.

    2003-01-01

    Our research was targeted at three issues: (1) the factors controlling ozone in the tropical troposphere, (2) the Asian outflow of ozone and its precursors, and (3) the causes of decadal trends observed in ozone and CO. We have also used support from this ACMAP grant to (1) work with Kelly Chance on the retrieval and interpretation of HCHO and NO2 observations from GOME, and (2) develop GEOS-CHEM into a versatile model supporting the work of a large number of users including outside Harvard. ACMAP has provided the core support for GEOS-CHEM development. Applications of the GEOS-CHEM model with primary support from ACMAP are discussed below. A list of publications resulting from this grant is given at the end of the report.

  12. Elevated ozone layers in the lower free troposphere during CalNex

    NASA Astrophysics Data System (ADS)

    Langford, A. O.; Senff, C. J.; Alvarez, R. J., II; Banta, R. M.; Brewer, A.; Hardesty, R.; Brioude, J.; Cooper, O. R.

    2010-12-01

    The NOAA ESRL/CSD nadir-viewing ozone and aerosol lidar (TOPAZ) was deployed aboard the NOAA AOC Twin Otter research aircraft during the 2010 CalNex campaign. Ozone measurements were made on a total of 46 research flights covering much of California between 23 May and 18 July 2010. Many of these flights found widespread layers of high ozone (i.e. >100 ppbv) at altitudes between 2 and 4 km above mean sea level in the free troposphere. Potential sources include stratospheric intrusions, orographic lifting, and transport from Asia. The lidar observations are compared to ground-based ozonesonde measurements, and the origins of these layers investigated using the FLEXPART trajectory and particle dispersion model.

  13. Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

    NASA Astrophysics Data System (ADS)

    Jiang, Zhe; Miyazaki, Kazuyuki; Worden, John R.; Liu, Jane J.; Jones, Dylan B. A.; Henze, Daven K.

    2016-05-01

    Significant progress has been made in identifying the influence of different processes and emissions on the summertime enhancements of free tropospheric ozone (O3) at northern midlatitude regions. However, the exact contribution of regional emissions, chemical and transport processes to these summertime enhancements is still not well quantified. Here we focus on quantifying the influence of regional emissions on the summertime O3 enhancements over the Middle East, using updated reactive nitrogen (NOx) emissions. We then use the adjoint of the GEOS-Chem model with these updated NOx emissions to show that the global total contribution of lightning NOx on middle free tropospheric O3 over the Middle East is about 2 times larger than that from global anthropogenic sources. The summertime middle free tropospheric O3 enhancement is primarily due to Asian NOx emissions, with approximately equivalent contributions from Asian anthropogenic activities and lightning. In the Middle Eastern lower free troposphere, lightning NOx from Europe and North America and anthropogenic NOx from Middle Eastern local emissions are the primary sources of O3. This work highlights the critical role of lightning NOx on northern midlatitude free tropospheric O3 and the important effect of the Asian summer monsoon on the export of Asian pollutants.

  14. Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Miyazaki, K.; Worden, J. R.; Liu, J. J.; Jones, D. B. A.; Henze, D. K.

    2015-12-01

    Significant progress has been made in identifying the influence of different processes and emissions on the summertime enhancements of free tropospheric ozone (O3) at northern mid-latitude regions. However, the exact contribution of regional emissions and chemical processing to these summertime enhancements is still not well quantified. Here we focus on quantifying the influence of regional emissions on the summertime O3 enhancements over the Middle East. We use updated reactive nitrogen (NOx) emissions from an ensemble Kalman Filter that assimilates satellite observations of nitrogen dioxide (NO2), O3, and carbon monoxide (CO) to provide an improved estimate of O3 precursor emissions. We then use the adjoint of the GEOS-Chem model with these updated NOx emissions to show that the global total contribution of lightning NOx on middle free tropospheric O3 over the Middle East is about three times larger than that from global anthropogenic sources. The summertime free tropospheric O3 enhancement is primarily due to Asian NOx emissions, with approximately equivalent contributions from Asian anthropogenic activities and lightning. In the Middle Eastern lower free troposphere, emissions from European and North American anthropogenic activities and from lightning NOx are the primary sources of O3. This work highlights the critical role of lightning NOx on northern mid-latitude free tropospheric O3 and the important effect of the Asian summer monsoon on the export of Asian pollutants.

  15. Impact of Enhanced Ozone Deposition and Halogen Chemistry on Tropospheric Ozone over the Northern Hemisphere.

    PubMed

    Sarwar, Golam; Gantt, Brett; Schwede, Donna; Foley, Kristen; Mathur, Rohit; Saiz-Lopez, Alfonso

    2015-08-01

    Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen chemistry in a comprehensive atmospheric modeling system. The enhanced ozone deposition treatment accounts for the interaction of iodide in seawater with ozone and increases deposition velocities by 1 order of magnitude. Halogen chemistry includes detailed chemical reactions of organic and inorganic bromine and iodine species. Two different simulations are completed with the halogen chemistry: without and with photochemical reactions of higher iodine oxides. Enhanced deposition reduces mean summer-time surface ozone by ∼3% over marine regions in the Northern Hemisphere. Halogen chemistry without the photochemical reactions of higher iodine oxides reduces surface ozone by ∼15% whereas simulations with the photochemical reactions of higher iodine oxides indicate ozone reductions of ∼48%. The model without these processes overpredicts ozone compared to observations whereas the inclusion of these processes improves predictions. The inclusion of photochemical reactions for higher iodine oxides leads to ozone predictions that are lower than observations, underscoring the need for further refinement of the halogen emissions and chemistry scheme in the model. PMID:26151227

  16. Scanning tropospheric ozone and aerosol lidar with double-gated photomultipliers.

    PubMed

    Machol, Janet L; Marchbanks, Richard D; Senff, Christoph J; McCarty, Brandi J; Eberhard, Wynn L; Brewer, William A; Richter, Ronald A; Alvarez, Raul J; Law, Daniel C; Weickmann, Ann M; Sandberg, Scott P

    2009-01-20

    The Ozone Profiling Atmospheric Lidar is a scanning four-wavelength ultraviolet differential absorption lidar that measures tropospheric ozone and aerosols. Derived profiles from the lidar data include ozone concentration, aerosol extinction, and calibrated aerosol backscatter. Aerosol calibrations assume a clear air region aloft. Other products include cloud base heights, aerosol layer heights, and scans of particulate plumes from aircraft. The aerosol data range from 280 m to 12 km with 5 m range resolution, while the ozone data ranges from 280 m to about 1.2 km with 100 m resolution. In horizontally homogeneous atmospheres, data from multiple-elevation angles is combined to reduce the minimum altitude of the aerosol and ozone profiles to about 20 m. The lidar design, the characterization of the photomultiplier tubes, ozone and aerosol analysis techniques, and sample data are described. Also discussed is a double-gating technique to shorten the gated turn-on time of the photomultiplier tubes, and thereby reduce the detection of background light and the outgoing laser pulse. PMID:19151820

  17. Laboratory investigations of the response of Brewer-Mast ozonesondes to tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Tarasick, David W.; Davies, Jonathan; Anlauf, Kurt; Watt, Maurice; Steinbrecht, Wolfgang; Claude, Hans J.

    2002-08-01

    The Brewer-Mast ozonesonde was used at Canadian stations from 1966 until 1980, when the Canadian network switched to the electrochemical concentration cell sonde. While the sondes appear to agree relatively well in the stratosphere, there is an evident discrepancy of 10-20% in tropospheric measurements [e.g., Tarasick et al., 1995, Figure 4]. Comparison of Brewer-Mast sondes with a calibrated ozone source yields some interesting insight into this discrepancy. Sonde response is strongly dependent on the preflight preparation procedures employed. Although sondes prepared via procedures introduced in the 1980s [Claude et al., 1987] perform quite well, when prepared according to the procedures used in Canada in the 1970s, Brewer-Mast sondes indicate 10-30% lower ozone than the calibrator. The following points are noted in particular: (1) a new Brewer-Mast sonde shows a large (~15%) increase in sensitivity between successive experiments; (2) especially at low (<100 ppb) O3 levels, the response even of previously flown sondes increases slowly with time; and (3) sondes show an additional slow increase of response with time that is apparently caused by ozone reactions with the phosphate buffer. The overall response curve indicated by 1, 2, and 3 implies that after correction to the observed total ozone, the earlier part of a flight would yield values that are too low, while the latter part would be too high. By applying a varying ozone input, simulating the typical variation in absolute ozone concentration experienced by a sonde in flight, we show that this can explain both the average correction factor (1.255) for the Canadian Brewer-Mast record and the 10-20% discrepancy in tropospheric measurements.

  18. Changes in air quality and tropospheric composition due to depletion of stratospheric ozone and interactions with climate.

    PubMed

    Tang, X; Wilson, S R; Solomon, K R; Shao, M; Madronich, S

    2011-02-01

    Air pollution will be directly influenced by future changes in emissions of pollutants, climate, and stratospheric ozone, and will have significant consequences for human health and the environment. UV radiation is one of the controlling factors for the formation of photochemical smog, which includes tropospheric ozone (O(3)) and aerosols; it also initiates the production of hydroxyl radicals (˙OH), which control the amount of many climate- and ozone-relevant gases (e.g., methane and HCFCs) in the atmosphere. Numerical models predict that future changes in UV radiation and climate will modify the trends and geographic distribution of ˙OH, thus affecting the formation of photochemical smog in many urban and regional areas. Concentrations of ˙OH are predicted to decrease globally by an average of 20% by 2100, with local concentrations varying by as much as a factor of two above and below current values. However, significant differences between modelled and measured values in a limited number of case studies show that chemistry of hydroxyl radicals in the atmosphere is not fully understood. Photochemically produced tropospheric ozone is projected to increase. If emissions of anthropogenic air pollutants from combustion of fossil fuels, burning of biomass, and agricultural activities continue to increase, concentrations of tropospheric O(3) will tend to increase over the next 20-40 years in certain regions of low and middle latitudes because of interactions of emissions, chemical processes, and climate change. Climate-driven increases in temperature and humidity will also increase production of tropospheric O(3) in polluted regions, but reduce it in more pristine regions. Higher temperatures tend to increase emissions of nitrogen oxides (NO(x)) from some soils and release of biogenic volatile organic compounds (VOCs) from vegetation, leading to greater background concentrations of ozone in the troposphere. The net effects of future changes in UV radiation

  19. Predicting tropospheric ozone and hydroxyl radical in a global, three-dimensional, chemistry, transport, and deposition model

    SciTech Connect

    Atherton, C.S.

    1995-01-05

    Two of the most important chemically reactive tropospheric gases are ozone (O{sub 3}) and the hydroxyl radical (OH). Although ozone in the stratosphere is a necessary protector against the sun`s radiation, tropospheric ozone is actually a pollutant which damages materials and vegetation, acts as a respiratory irritant, and is a greenhouse gas. One of the two main sources of ozone in the troposphere is photochemical production. The photochemistry is initiated when hydrocarbons and carbon monoxide (CO) react with nitrogen oxides (NO{sub x} = NO + NO{sub 2}) in the presence of sunlight. Reaction with the hydroxyl radical, OH, is the main sink for many tropospheric gases. The hydroxyl radical is highly reactive and has a lifetime on the order of seconds. Its formation is initiated by the photolysis of tropospheric ozone. Tropospheric chemistry involves a complex, non-linear set of chemical reactions between atmospheric species that vary substantially in time and space. To model these and other species on a global scale requires the use of a global, three-dimensional chemistry, transport, and deposition (CTD) model. In this work, I developed two such three dimensional CTD models. The first model incorporated the chemistry necessary to model tropospheric ozone production from the reactions of nitrogen oxides with carbon monoxide (CO) and methane (CH{sub 4}). The second also included longer-lived alkane species and the biogenic hydrocarbon isoprene, which is emitted by growing plants and trees. The models` ability to predict a number of key variables (including the concentration of O{sub 3}, OH, and other species) were evaluated. Then, several scenarios were simulated to understand the change in the chemistry of the troposphere since preindustrial times and the role of anthropogenic NO{sub x} on present day conditions.

  20. Effect of some climatic parameters on tropospheric and total ozone column over Alipore ( 22.52 ∘ N, 88.33 ∘ E), India

    NASA Astrophysics Data System (ADS)

    Jana, P. K.; Bhattacharyya, S.; Banerjee, A.

    2014-10-01

    The paper presents the nature of variations of tropospheric and total ozone column retrieved from the Convective Cloud Differential (CCD) technique, Ozone Monitoring Instrument (OMI), and Total Ozone Mapping Spectrometer (TOMS) data, National Aeronautics and Space Administrations (NASA), USA, respectively; surface temperature, relative humidity, total rainfall, ozone precursors (non-methane hydrocarbon, carbon monoxide, nitrogen dioxide, and sulphur dioxide) that are collected from India Meteorological Department (IMD), Alipore, Kolkata; solar insolation obtained from Solar Geophysical Data Book and El-Niño index collected from National Climatic Data Center, US Department of Commerce, National Oceanic and Atmospheric Administration, USA. The effect of these climatic parameters and ozone precursors on ozone variations is critically analyzed and explained on the basis of linear regression and correlation. It has been observed that the maximum, minimum and mean temperature, relative humidity, solar insolation, tropospheric, and total ozone column (TOC) showed slight increasing tendencies from October 2004 to December 2011, while total rainfall and El-Niño index showed little decreasing tendencies for the same period. Amongst selected climatic parameters and ozone precursors, the solar insolation and the average temperature had a significant influence on both, the tropospheric ozone and total ozone column formation. The solar insolation had contributed more in tropospheric ozone than in total ozone column; while El-Niño index had played a more significant role in total ozone column build up than in tropospheric ozone. Negative correlation was observed between almost all ozone precursors with the tropospheric and total ozone. The tropospheric ozone and total ozone column were also significantly correlated. The level of significance and contribution of different climatic parameters are determined from correlation technique and Multiple Linear Regression (MLR) method

  1. Impact of enhanced ozone deposition and halogen chemistry on tropospheric ozone over the Northern Hemisphere

    EPA Science Inventory

    Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen ch...

  2. Tropospheric ozone and plants: absorption, responses, and consequences.

    PubMed

    Cho, Kyoungwon; Tiwari, Supriya; Agrawal, S B; Torres, N L; Agrawal, Madhoolika; Sarkar, Abhijit; Shibato, Junko; Agrawal, Ganesh K; Kubo, Akihiro; Rakwal, Randeep

    2011-01-01

    Ozone is now considered to be the second most important gaseous pollutant in our environment. The phytotoxic potential of O₃ was first observed on grape foliage by B.L. Richards and coworkers in 1958 (Richards et al. 1958). To date, unsustainable resource utilization has turned this secondary pollutant into a major component of global climate change and a prime threat to agricultural production. The projected levels to which O₃ will increase are critically alarming and have become a major issue of concern for agriculturalists, biologists, environmentalists and others plants are soft targets for O₃. Ozone enters plants through stomata, where it disolves in the apoplastic fluid. O₃ has several potential effects on plants: direct reaction with cell membranes; conversion into ROS and H₂O₂ (which alters cellular function by causing cell death); induction of premature senescence; and induction of and up- or down-regulation of responsive components such as genes , proteins and metabolites. In this review we attempt to present an overview picture of plant O₃ interactions. We summarize the vast number of available reports on plant responses to O₃ at the morphological, physiological, cellular, biochemical levels, and address effects on crop yield, and on genes, proteins and metabolites. it is now clear that the machinery of photosynthesis, thereby decreasing the economic yield of most plants and inducing a common morphological symptom, called the "foliar injury". The "foliar injury" symptoms can be authentically utilized for biomonitoring of O₃ under natural conditions. Elevated O₃ stress has been convincingly demonstrated to trigger an antioxidative defense system in plants. The past several years have seen the development and application of high-throughput omics technologies (transcriptomics, proteomics, and metabolomics) that are capable of identifying and prolifiling the O₃-responsive components in model and nonmodel plants. Such studies have been

  3. 2003 megafires in Australia: impact on tropospheric ozone and aerosols

    NASA Astrophysics Data System (ADS)

    Guerova, G.; Jones, N.

    2009-01-01

    2003 was a record year for wildfires worldwide. Severe forest fires killed four people, displaced 20 500 others and burnt 260 000 ha in South-East Australia in January 2003. The uncontrolled fires ignited in early January 2003 as a result of a prolonged El Niño drought in South-East Australia. Severe weather conditions resulted in a fast spread of the fires and poor air quality in a region where 70% of the population of Australia lives. We use state-of-art global chemistry and transport model GEOS-Chem in conjunction with ground- and space-based observations to study the ozone (O3) and aerosol enhancement due to fires. Firstly, the monthly mean surface O3 and Aerosol Optical Depth (AOD) in January 2003 are compared to January 2004 and, secondly, from sensitivity model simulations, four episodes are isolated and an attempt is made to quantify the contribution of the fires to air quality in south and South-East Australia. In January 2003 the observed monthly mean afternoon surface O3 in Victoria (VIC) and South Australia (SA) reached 27.5 ppb, which is 6.5 ppb (i.e. 30%) higher than in 2004. The simulated O3 is 29.5 ppb, which is 10 ppb higher than in 2004. While the model tends to overestimate the observed peak O3, it exhibits very good skill in reproducing the O3 temporal variability in January 2003 with a correlation of 0.83. In VIC, the air quality 4-h ozone (O3) standard exceedences are reported on 17, 24 and 25 January. On 12, 17, 24-25 and 29 January 2003, the observed O3 peaks above 40 ppb and the simulated fire contribution is higher than 10 ppb. During these 4 episodes, the range of observed O3 enhancement due to fires is 20-35 ppb, which is a factor of 3 to 5 higher than the monthly mean. The simulated fire O3 enhancement is in the range 15-50 ppb with a factor of 1.5 to 5 higher than the monthly mean. During two episodes, a well-formed surface wind channel stretches across the Tasman Sea facilitating the long range transport to New Zealand contributing

  4. New Perspectives from Satellite and Profile Observations on Tropospheric Ozone over Africa and the Adjacent Oceans: An Indian-Atlantic Ocean Link to tbe "Ozone Paradox"

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Diab, Roseanne D.; Thouret, Valerie; Sauvage, Bastien; Chatfield, B.; Guan, Hong

    2004-01-01

    In the past few years, tropospheric ozone observations of Africa and its adjacent ocenas have been greatly enhanced by high resolution (spatial and temporal) satellite measurements and profile data from aircraft (MOZAIC) and balloon-borne (SHADOZ) soundings. These views have demonstrated for the first time the complexity of chemical-dynamical interactions over the African continent and the Indian and Atlantic Oceans. The tropical Atlantic "ozone paradax" refers to the observation that during the season of maximum biomass burning in west Africa north of the Intertropical Convergence Zone (ITCZ), the highest tropospheric ozone total column occurs south of the ITCZ over the tropical Atlantic. The longitudinal view of tropospheric ozone in the southern tropics from SHADOZ (Southern Hemisphere Additional Ozonesondes) soundings shown the persistence of a "zonal-wave one" pattern that reinforces the "ozone paradox". These ozone features interact with dynamics over southern and northern Africa where anthropogenic sources include the industrial regions of the South African Highveld and Mideastern-Mediterranean influences, respectively. Our newest studies with satellites and soundings show that up to half the ozone pollution over the Atlantic in the January-March "paradox" period may originate from south Asian pollution. Individual patches of pollurion over the Indian Ocean are transported upward by convective mixing and are enriched by pyrogenic, biogenic sources and lightning as they cross Africa and descend over the Atlantic. In summary, local sources, intercontinental import and export and unique regional transport patterns put Africa at a crossroads of troposheric ozone influences.

  5. Multiannual tropical tropospheric ozone columns and the case of the 2015 el Niño event

    NASA Astrophysics Data System (ADS)

    Leventidou, Elpida; Eichmann, Kai-Uwe; Weber, Mark; Burrows, John P.

    2016-04-01

    Stratospheric ozone is well known for protecting the surface from harmful ultraviolet solar radiation whereas ozone in the troposphere plays a more complex role. In the lower troposphere ozone can be extremely harmful for human health as it can oxidize biological tissues and causes respiratory problems. Several studies have shown that the tropospheric ozone burden (300±30Tg (IPCC, 2007)) increases by 1-7% per decade in the tropics (Beig and Singh, 2007; Cooper et al., 2014) which makes the need to monitor it on a global scale crucial. Remote sensing from satellites has been proven to be very useful in providing consistent information of tropospheric ozone concentrations over large areas. Tropical tropospheric ozone columns can be retrieved with the Convective Cloud Differential (CCD) technique (Ziemke et al. 1998) using retrieved total ozone columns and cloud parameters from space-borne observations. We have developed a CCD-IUP algorithm which was applied to GOME/ ERS-2 (1995-2003), SCIAMACHY/ Envisat (2002-2012), and GOME-2/ MetOpA (2007-2012) weighting function DOAS (Coldewey-Egbers et al., 2005, Weber et al., 2005) total ozone data. A unique long-term record of monthly averaged tropical tropospheric ozone columns (20°S - 20°N) was created starting in 1996. This dataset has been extensively validated by comparisons with SHADOZ (Thompson et al., 2003) ozonesonde data and limb-nadir Matching (Ebojie et al. 2014) tropospheric ozone data. The comparison shows good agreement with respect to range, inter-annual variation, and variance. Biases where found to be within 5DU and the RMS errors less than 10 DU. This 17-years dataset has been harmonized into one consistent time series, taking into account the three instruments' difference in ground pixel size. The harmonised dataset is used to determine tropical tropospheric ozone trends and climatological values. The 2015 el Niño event has been characterised as one of the top three strongest el Niños since 1950. El Ni

  6. Monitoring Tropospheric Ozone Enhancement in the Front Range Using the Gsfc Tropoz DIAL during Discover - AQ 2014

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Hoff, R. M.; Twigg, L.; Sumnicht, G. K.

    2014-12-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Fort Collins, CO from 200 m to 16 km AGL. These measurements were taken as part of NASA's DISCOVER-AQ campaign in July/August 2014. Measurements were made during simultaneous aircraft spirals over the lidar site as well as collocated ozonesonde launches. Ozone enhancement from local sources typically occurred in the mid-afternoon convection period, especially when there was light winds and low cloud cover. Interesting ozone profiles and time series data will be shown. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. Three of these lidars, including the GSFC TROPOZ DIAL, recorded measurements during the DISCOVER-AQ campaign. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived.

  7. Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change.

    PubMed

    Wilson, S R; Solomon, K R; Tang, X

    2007-03-01

    It is well-understood that reductions in air quality play a significant role in both environmental and human health. Interactions between ozone depletion and global climate change will significantly alter atmospheric chemistry which, in turn, will cause changes in concentrations of natural and human-made gases and aerosols. Models predict that tropospheric ozone near the surface will increase globally by up to 10 to 30 ppbv (33 to 100% increase) during the period 2000 to 2100. With the increase in the amount of the stratospheric ozone, increased transport from the stratosphere to the troposphere will result in different responses in polluted and unpolluted areas. In contrast, global changes in tropospheric hydroxyl radical (OH) are not predicted to be large, except where influenced by the presence of oxidizable organic matter, such as from large-scale forest fires. Recent measurements in a relatively clean location over 5 years showed that OH concentrations can be predicted by the intensity of solar ultraviolet radiation. If this relationship is confirmed by further observations, this approach could be used to simplify assessments of air quality. Analysis of surface-level ozone observations in Antarctica suggests that there has been a significant change in the chemistry of the boundary layer of the atmosphere in this region as a result of stratospheric ozone depletion. The oxidation potential of the Antarctic boundary layer is estimated to be greater now than before the development of the ozone hole. Recent modeling studies have suggested that iodine and iodine-containing substances from natural sources, such as the ocean, may increase stratospheric ozone depletion significantly in polar regions during spring. Given the uncertainty of the fate of iodine in the stratosphere, the results may also be relevant for stratospheric ozone depletion and measurements of the influence of these substances on ozone depletion should be considered in the future. In agreement with

  8. Tropospheric Ozone Over a Tropical Atlantic Station in the Northern Hemisphere: Paramaribo, Surinam (6 deg N, 55 deg W)

    NASA Technical Reports Server (NTRS)

    Peters, W.; Krol, M. C.; Fortuin, J. P. F.; Kelder, H. M.; Thompson, A. M.; Becker, C. R.; Lelieveld, J.; Crutzen, P. J.

    2003-01-01

    We present an analysis of 2.5 years of weekly ozone soundings conducted at a new monitoring station in Paramaribo, Surinam (6 deg N,55 deg W). This is currently one of only three ozone sounding stations in the northern hemisphere (NH) tropics, and the only one in the equatorial Atlantic region. Paramaribo is part of the Southern Hemisphere ADditional Ozone Sounding program (SHADOZ). Due to its position close to the equator, the Inter Tropical Convergence Zone (ITCZ) passes over Paramaribo twice per year, which results in a semi-annual seasonality of many parameters including relative humidity and ozone. The dataset from Paramaribo is used to: (1) evaluate ozone variability relative to precipitation, atmospheric circulation patterns and biomass burning; (2) contrast ozone at the NH equatorial Atlantic with that at nearby southern hemisphere (SH) stations Natal (6 deg S,35 deg W) and Ascension (8 deg S,14 deg W); (3) compare the seasonality of tropospheric ozone with a satellite-derived ozone product: Tropical Tropospheric Ozone Columns from the Modified Residual method (MR-TTOC). We find that Paramaribo is a distinctly Atlantic station. Despite its position north of the equator, it resembles nearby SH stations during most of the year. Transport patterns in the lower and middle troposphere during February and March differ from SH stations, which leads to a seasonality of ozone with two maxima. MR-TTOC over Paramaribo does not match the observed seasonality of ozone due to the use of a SH ozone sonde climatology in the MR method. The Paramaribo ozone record is used to suggest an improvement for northern hemisphere MR-TTOC retrievals. We conclude that station Paramaribo shows unique features in the region, and clearly adds new information to the existing SHADOZ record.

  9. Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Emili, E.; Barret, B.; Massart, S.; Le Flochmoen, E.; Piacentini, A.; El Amraoui, L.; Pannekoucke, O.; Cariolle, D.

    2013-08-01

    Accurate and temporally resolved fields of free-troposphere ozone are of major importance to quantify the intercontinental transport of pollution and the ozone radiative forcing. In this study we examine the impact of assimilating ozone observations from the Microwave Limb Sounder (MLS) and the Infrared Atmospheric Sounding Interferometer (IASI) in a global chemical transport model (MOdèle de Chimie Atmosphérique à Grande Échelle, MOCAGE). The assimilation of the two instruments is performed by means of a variational algorithm (4-D-VAR) and allows to constrain stratospheric and tropospheric ozone simultaneously. The analysis is first computed for the months of August and November 2008 and validated against ozone-sondes measurements to verify the presence of observations and model biases. It is found that the IASI Tropospheric Ozone Column (TOC, 1000-225 hPa) should be bias-corrected prior to assimilation and MLS lowermost level (215 hPa) excluded from the analysis. Furthermore, a longer analysis of 6 months (July-August 2008) showed that the combined assimilation of MLS and IASI is able to globally reduce the uncertainty (Root Mean Square Error, RMSE) of the modeled ozone columns from 30% to 15% in the Upper-Troposphere/Lower-Stratosphere (UTLS, 70-225 hPa) and from 25% to 20% in the free troposphere. The positive effect of assimilating IASI tropospheric observations is very significant at low latitudes (30° S-30° N), whereas it is not demonstrated at higher latitudes. Results are confirmed by a comparison with additional ozone datasets like the Measurements of OZone and wAter vapour by aIrbus in-service airCraft (MOZAIC) data, the Ozone Monitoring Instrument (OMI) total ozone columns and several high-altitude surface measurements. Finally, the analysis is found to be little sensitive to the assimilation parameters and the model chemical scheme, due to the high frequency of satellite observations compared to the average life-time of free-troposphere

  10. Development of a Climate Record of Tropospheric and Stratospheric Column Ozone from Satellite Remote Sensing: Evidence of an Early Recovery of Global Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerald R.; Chandra, Sushil

    2012-01-01

    Ozone data beginning October 2004 from the Aura Ozone Monitoring Instrument (OMI) and Aura Microwave Limb Sounder (MLS) are used to evaluate the accuracy of the Cloud Slicing technique in effort to develop long data records of tropospheric and stratospheric ozone and for studying their long-term changes. Using this technique, we have produced a 32-yr (1979-2010) long record of tropospheric and stratospheric column ozone from the combined Total Ozone Mapping Spectrometer (TOMS) and OMI. Analyses of these time series suggest that the quasi-biennial oscillation (QBO) is the dominant source of inter-annual variability of stratospheric ozone and is clearest in the Southern Hemisphere during the Aura time record with related inter-annual changes of 30- 40 Dobson Units. Tropospheric ozone for the long record also indicates a QBO signal in the tropics with peak-to-peak changes varying from 2 to 7 DU. The most important result from our study is that global stratospheric ozone indicates signature of a recovery occurring with ozone abundance now approaching the levels of year 1980 and earlier. The negative trends in stratospheric ozone in both hemispheres during the first 15 yr of the record are now positive over the last 15 yr and with nearly equal magnitudes. This turnaround in stratospheric ozone loss is occurring about 20 yr earlier than predicted by many chemistry climate models. This suggests that the Montreal Protocol which was first signed in 1987 as an international agreement to reduce ozone destroying substances is working well and perhaps better than anticipated.

  11. The Role of Lightning in Controlling Interannual Variability of Tropical Tropospheric Ozone and OH and its Implications for Climate

    NASA Technical Reports Server (NTRS)

    Murray, Lee T.; Jacob, Daniel J.; Logan, Jennifer A.; Hudman, Rynda C.; Koshak, William J.

    2012-01-01

    Nitrogen oxides (NO(x) = NO + NO2) produced by lightning make a major contribution to the production of the dominant tropospheric oxidants (OH and ozone). These oxidants control the lifetime of many trace gases including long-lived greenhouse gases, and control the source-receptor relationship of inter-hemispheric pollutant transport. Lightning is affected by meteorological variability, and therefore represents a potentially important tropospheric chemistry-climate feedback. Understanding how interannual variability (IAV) in lightning affects IAV in ozone and OH in the recent past is important if we are to predict how oxidant levels may change in a future warmer climate. However, lightning parameterizations for chemical transport models (CTMs) show low skill in reproducing even climatological distributions of flash rates from the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) satellite instruments. We present an optimized regional scaling algorithm for CTMs that enables sufficient sampling of spatiotemporally sparse satellite lightning data from LIS to constrain the spatial, seasonal, and interannual variability of tropical lightning. We construct a monthly time series of lightning flash rates for 1998-2010 and 35degS-35degN, and find a correlation of IAV in total tropical lightning with El Nino. We use the IAV-constraint to drive a 9-year hindcast (1998-2006) of the GEOS-Chem 3D chemical transport model, and find the increased IAV in LNO(x) drives increased IAV in ozone and OH, improving the model fs ability to simulate both. Although lightning contributes more than any other emission source to IAV in ozone, we find ozone more sensitive to meteorology, particularly convective transport. However, we find IAV in OH to be highly sensitive to lightning NO(x), and the constraint improves the ability of the model to capture the temporal behavior of OH anomalies inferred from observations of methyl chloroform and other gases. The sensitivity of

  12. The 1998-2000 SHADOZ (Southern Hemisphere ADditional OZonesondes) Tropical Ozone Climatology. 2; Stratospheric and Tropospheric Ozone Variability and the Zonal Wave-One

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Witte, Jacquelyn C.; Oltmans, Samuel J.; Schmidlin, Francis J.; Logan, Jennifer A.; Fujiwara, Masatomo; Kirchhoff, Volker W. J. H.; Posny, Francoise; Coetzee, Gert J. R.; Hoegger, Bruno; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    This is the second 'reference' or 'archival' paper for the SHADOZ (Southern Hemisphere Additional Ozonesondes) network and is a follow-on to the recently accepted paper with similar first part of title. The latter paper compared SHADOZ total ozone with satellite and ground-based instruments and showed that the equatorial wave-one in total ozone is in the troposphere. The current paper presents details of the wave-one structure and the first overview of tropospheric ozone variability over the southern Atlantic, Pacific and Indian Ocean basins. The principal new result is that signals of climate effects, convection and offsets between biomass burning seasonality and tropospheric ozone maxima suggest that dynamical factors are perhaps more important than pollution in determining the tropical distribution of tropospheric ozone. The SHADOZ data at () are setting records in website visits and are the first time that the zonal view of tropical ozone structure has been recorded - thanks to the distribution of the 10 sites that make up this validation network.

  13. Discoveries about Tropical Tropospheric Ozone from Satellite and SHADOZ (Southern Hemisphere Additional Ozonesondes) and a Future Perspective on NASA's Ozone Sensors

    NASA Technical Reports Server (NTRS)

    Thompson, Anne

    2003-01-01

    We have been producing near-real tropical tropospheric ozone ('TTO') data from TOMS since 1997 with Prof. Hudson and students at the University of Maryland. Maps for 1996-2000 for the operational Earth-Probe instrument reside at: . We also have archived 'TTO' data from the Nimbus 7/TOMS satellite (1979-1992). The tropics is a region strongly influenced by natural variability and anthropogenic activity and the satellite data have been used to track biomass burning pollution and to detect interannual variability and climate signals in ozone. We look forward to future ozone sensors from NASA; four will be launched in 2004 as part of the EOS AURA Mission. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical variability. Thus, in 1998, NASA's Goddard Space Flight Center, NOAA's Climate Monitoring and Diagnostics Laboratory (CMDL) and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches at selected sites and provides a public archive of ozonesonde data from twelve tropical and subtropical stations at http://croc.nsfc.nasa.gov/shadoz. The stations are: Ascension Island; Nairobi, Kenya; Irene, South Africa; R,union Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil, Malindi, Kenya; Paramaribo, Surinam. From the first 3-4 years of data (presently greater than 1700 sondes), the following features emerge: (a) highly variable tropospheric ozone; (b) a zonal wave-one pattern in tropospheric column ozone; (c) tropospheric ozone variability over the Indian and Pacific Ocean displays strong convective signatures.

  14. The Role of Eddies in Tropospheric Circulation Trends Associated with Stratospheric Ozone Reduction in the Boreal Summer

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Yamazaki, K.; Akiyoshi, H.

    2013-12-01

    We examined the impact of long-term trends in stratospheric ozone on the troposphere by investigating radiative heating anomalies caused by stratospheric ozone changes and associated changes in dynamical fields. We applied a linear trend analysis to five reanalysis datasets and five chemistry climate models (CCM) for the boreal summer (June-July-August) during an ozone-depleting period (1981-2000). CCM simulations with depleting ozone and fixed GHGs and SSTs showed a poleward shift of the subtropical jet and Hadley cell expansion. Reanalysis data also showed this poleward shift. We inferred that the ozone anomaly induced negative potential vorticity (PV) anomalies near the tropopause by causing anomalous radiative cooling. To separate direct radiative impacts from indirect eddy forcing, we used a PV inversion technique. The PV-induced zonal wind anomalies showed a poleward shift of the subtropical jet, but magnitudes were small in the low to middle troposphere. We used a dry general circulation model to examine the modification of tropospheric eddies by the basic state change due to the PV anomalies. The result showed that anomalous wave forcing in the upper troposphere accelerates (decelerates) the zonal wind north (south) of the jet. The deceleration forcing south of the jet drives the anomalous residual mean circulation in the lower latitudes, explaining the Hadley cell expansion. The Coriolis force associated with the anomalous residual mean circulation extends the zonal wind anomaly to the lower troposphere. These results suggest that stratospheric ozone, by modifying eddy activity in the troposphere, plays an important role in tropospheric climate change.

  15. Comparison of satellite-based instantaneous radiative forcing of tropospheric ozone to four global chemistry climate models

    NASA Astrophysics Data System (ADS)

    Aghedo, A. M.; Bowman, K. W.; Worden, H. M.; Shindell, D. T.; Faluvegi, G.; Lamarque, J.; Kulawik, S. S.; Parrington, M.; Horowitz, L. W.; Jones, D. B.; Rast, S.; Schultz, M. G.; Pozzoli, L.

    2009-12-01

    Radiative forcing is the perturbation to the Earth's radiation balance from changes in an atmospheric constituent. Ozone is a radiatively significant atmospheric species through its absorption of both shortwave and longwave radiation. Driven primarily by longwave absorption in the troposphere, ozone exerts the third largest positive radiative forcing, following carbon dioxide and methane, with an estimate of 0.35 W/m2 (0.25 - 0.65 W/m2) according to the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC AR4), Climate Change 2007. We use the spectrally resolved outgoing longwave radiation sensitivity to tropospheric ozone from the Tropospheric Emissions Spectrometer (TES) measurements to calculate the three-dimensional instantaneous radiative forcing (IRF) kernel under all-sky conditions in August 2006. These kernels were applied to ozone concentration calculated by four different state-of-the-art global chemistry-climate models, which are AM2-Chem, CAM-Chem, ECHAM5-MOZ and G-PUCCINI, to provide an observation-based estimate of model IRF. Primary differences in IRF are due to varying estimate of sub-tropical and upper tropospheric ozone concentration, leading to model tropospheric IRF bias of between -0.4 to +0.7 W/m2. We show that the multi-model ensemble average IRF values are closest to TES estimate.

  16. Development and field deployment of an instrument to measure ozone production rates in the troposphere

    NASA Astrophysics Data System (ADS)

    Sklaveniti, S.; Locoge, N.; Dusanter, S.; Leonardis, T.; Lew, M.; Bottorff, B.; Sigler, P. S. R.; Stevens, P. S.; Wood, E. C. D.; Kundu, S.; Gentner, D. R.

    2015-12-01

    Ozone is a greenhouse gas and a primary constituent of urban smog, irritating the respiratory system and damaging the vegetation. The current understanding of ozone chemistry in the troposphere indicates that net ozone production P(O3) occurs when peroxy radicals (HO2+RO2) react with NO producing NO2, whose photolysis leads to O3 formation. P(O3) values can be calculated from peroxy radical concentrations, either from ambient measurements or box model outputs. These two estimation methods often disagree for NOx mixing ratios higher than a few ppb, questioning our ability to measure peroxy radicals under high NOx conditions or indicating that there are still unknowns in our understanding of the radical and ozone production chemistry. Direct measurements of ozone production rates will help to address this issue and improve air quality regulations. We will present the development of an instrument for direct measurements of ozone production rates (OPR). The OPR instrument consists of three parts: (i) two quartz flow tubes sampling ambient air ("Ambient" and "Reference" flow tube), (ii) an O3-to-NO2 conversion unit, and (iii) a Cavity Attenuated Phase Shift (CAPS) monitor to measure NO2. The air in the Ambient flow tube undergoes the same photochemistry as in ambient air, while the Reference flow tube is covered by a UV filter limiting the formation of ozone. Exiting the flow tubes, ozone is converted into NO2 and the sum O3+NO2 (Ox) is measured by the CAPS monitor. The difference in Ox between the two flow tubes divided by the residence time yields the Ox production rate, P(Ox). P(O3) is assumed to be equal to P(Ox) when NO2 is efficiently photolyzed during daytime. We will present preliminary results from the Indiana Radical, Reactivity and Ozone Production Intercomparison (IRRONIC) campaign in Bloomington, Indiana, during July 2015, where ozone production rates were measured by introducing various amounts of NO inside the flow tubes to investigate the ozone

  17. Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

    NASA Astrophysics Data System (ADS)

    Emili, Emanuele; Barret, Brice; Massart, Sebastien; Piacentini, Andrea; Pannekoucke, Olivier; Cariolle, Daniel

    2013-04-01

    Ozone acts as the main shield against UV radiation in the stratosphere, it contributes to the greenhouse effect in the troposphere and it is a major pollutant in the planetary boundary layer. In the last decades models and satellite observations reached a mature level, providing estimates of ozone with an accuracy of few percents in the stratosphere. On the other hand, tropospheric ozone still represents a challenge, because its signal is less detectable by space-borne sensors, its modelling depends on the knowledge of gaseous emissions at the surface, and stratosphere/troposphere exchanges might rapidly increase its abundance by several times. Moreover there is generally lack of in-situ observations of tropospheric ozone in many regions of the world. For these reasons the assimilation of satellite data into chemical transport models represents a promising technique to overcome limitations of both satellites and models. The objective of this study is to assess the value of vertically resolved observations from the Infrared Atmospheric Sounding Interferometer (IASI) and the Microwave Limb Sounder (MLS) to constrain both the tropospheric and stratospheric ozone profile in a global model. While ozone total columns and stratospheric profiles from UV and microwave sensors are nowadays routinely assimilated in operational models, still few studies have explored the assimilation of ozone products from IR sensors such as IASI, which provide better sensitivity in the troposphere. We assimilate both MLS ozone profiles and IASI tropospheric (1000-225 hPa) ozone columns in the Météo France chemical transport model MOCAGE for 2008. The model predicts ozone concentrations on a 2x2 degree global grid and for 60 vertical levels, ranging from the surface up to 0.1 hPa. The assimilation is based on a 4D-VAR algorithm, employs a linear chemistry scheme and accounts for the satellite vertical sensitivity via the averaging kernels. The assimilation of the two products is first tested

  18. Seasonal source contributions of tropospheric ozone over East Asia based on CMAQ-HDDM

    NASA Astrophysics Data System (ADS)

    Itahashi, Syuichi; Uno, Itsushi; Kim, Soontae

    2013-05-01

    Determining the source contributions of tropospheric ozone concentration is an important issue for East Asia, due to the dramatic and rapid increase in emissions of atmospheric pollutants. To achieve this, the higher-order decoupled direct method (HDDM), a technique for efficient calculation of sensitivities, was applied in this study. Tropospheric ozone concentrations at observation sites located in remote areas of Japan were well-reproduced by Community Multi-scale Air Quality (CMAQ) model simulations, and exhibited a maximum peak in spring, a relatively small peak in autumn and a summer minimum. This seasonal pattern is a reflection of long-range transport and chemical processes, coupled with continental-oceanic air mass exchanges forced by the East Asian monsoon. For the HDDM simulation, we focused on episodic pollution events during each season of 2007 to clarify the seasonal characteristics, and then assessed source contributions paying attention to both precursor emissions (NOx and VOC) and source regions (China, central eastern China, Korea, and Japan). An ozone-sensitive regime (NOx- or VOC-sensitive regime) was also determined based on the HDDM results. This suggested a regime over East Asia that was NOx sensitive in summer, VOC sensitive in winter, and either NOx or VOC sensitive during spring and autumn. At observation sites in remote areas of Japan, by separating the precursor contribution into NOx and VOC components of ozone production, it was found that the contribution of NOx emissions was larger than that of VOC emissions in spring, autumn, and especially summer, therefore, a reduction in NOx emissions could reduce the severity of episodes of tropospheric ozone pollution in downwind areas. Due to the strong VOC-sensitive conditions in winter, NOx emissions enabled a reduction in surface ozone concentrations. In terms of the contributions attributed to source regions, the source contribution of China was relatively high during spring, but local

  19. Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

    NASA Astrophysics Data System (ADS)

    Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

    2015-01-01

    Because tropospheric ozone is both a~greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change and stratospheric ozone recovery on the tropospheric ozone budget, in a~simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0. Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximises in the early 21st century at 23%. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70 year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally-averaged northern midlatitude ozone because of increasing emissions from Asia, together with the longevity of ozone in the troposphere. A~simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6 % increase in global-mean tropospheric ozone, and an 11% increase at northern midlatitudes. This increase maximises in the 2080s, and is mostly caused by methane, which maximises in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its influence on other VOCs and CO. Enhanced flux of ozone from the stratosphere to the troposphere as well as climate change-induced enhancements in

  20. Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0

    NASA Astrophysics Data System (ADS)

    Revell, L. E.; Tummon, F.; Stenke, A.; Sukhodolov, T.; Coulon, A.; Rozanov, E.; Garny, H.; Grewe, V.; Peter, T.

    2015-05-01

    Because tropospheric ozone is both a greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry-climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change (including methane effects) and stratospheric ozone recovery on the tropospheric ozone budget, in a simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0 (a medium-high, and reasonably realistic climate scenario). Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximizes in the early 21st century at 23% compared to 1960. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70-year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally averaged northern midlatitude ozone because of increasing emissions from Asia, together with the long lifetime of ozone in the troposphere. A simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6% increase in global-mean tropospheric ozone by the end of the 21st century, with an 11 % increase at northern midlatitudes. This increase maximizes in the 2080s and is mostly caused by methane, which maximizes in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its

  1. The importance of ozone in the oxidation of sulfur dioxide in nonurban tropospheric clouds

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1982-01-01

    In studies of the various possible mechanisms which contribute to the conversion of atmospheric sulfur dioxide to sulfate aerosol in the atmosphere, oxidation within the aqueous, droplet phase of tropospheric clouds has been identified as a major contributor. It has appeared that possibly much of this oxidation is by hydrogen peroxide, with the contribution from ozone being only minimal. The present investigation is concerned with the relative importance of O3 and H2O2 oxidation as a function of pH. The results of a new experimental study of the O3-S(IV) reaction in aqueous solution are presented, and potential S(IV) oxidation rates by O3 in cloud water are compared with those predicted for H2O2. The investigation indicates the potential importance of O3 as a contributor to the overall oxidative conversion of SO2 within typical nonpolluted tropospheric clouds.

  2. Correlations between ozone and carbon monoxide in the lower stratosphere, folded tropopause, and maritime troposphere

    NASA Technical Reports Server (NTRS)

    Hipskind, R. Stephen; Gregory, Gerald L.; Sachse, Glen W.; Hill, G. F.; Danielsen, Edwin F.

    1987-01-01

    The variations of ozone and carbon monoxide with respect to the atmospheric flow structure are investigated for two aircraft flights: one in the upper troposphere/lower stratosphere over the continental United States on April 20, 1984, and the other in the marine troposphere over the eastern Pacific on April 26, 1984. The high frequency (1 Hz) and precision of the measurements allow detailed analysis of the species distribution down to length scales of the order of 1 km. Correlations between the two species are made on large, medium, and small scales of motion, and the results are interpreted. In general, the correlations are negative with some regions of positive correlation. The interpretation of these results is discussed.

  3. Role of deep cloud convection in the ozone budget of the troposphere.

    PubMed

    Lelieveld, J; Crutzen, P J

    1994-06-17

    Convective updrafts in thunderstorms prolong the lifetime of ozone (O(3)) and its anthropogenic precursor NOx [nitric oxide (NO) + nitrogen dioxide (NO(2))] by carrying these gases rapidly upward from the boundary layer into a regime where the O(3) production efficiency is higher, chemical destruction is slower, and surface deposition is absent. On the other hand, the upper troposphere is relatively rich in O(3) and NOx from natural sources such as downward transport from the stratosphere and lightning; convective overturning conveys the O(3) and NOx toward the Earth's surface where these components are more efficiently removed from the atmosphere. Simulations with a three-dimensional global model suggest that the net result of these counteractive processes is a 20 percent overall reduction in total tropospheric O(3). However, the net atmospheric oxidation efficiency is enhanced by 10 to 20 percent. PMID:17839912

  4. Effects of 1997 Indonesian forest fires on tropospheric ozone enhancement, radiative forcing, and temperature change over the Hong Kong region

    NASA Astrophysics Data System (ADS)

    Chan, C. Y.; Chan, L. Y.; Zheng, Y. G.; Harris, J. M.; Oltmans, S. J.; Christopher, S.

    2001-07-01

    Tropospheric ozone enhancements were measured over Hong Kong (22.2°N, 114.3°E) by electrochemical concentration cell ozonesondes during the 1997 period when many forest fires were burning in Indonesia. The enhancements have a maximum ozone concentration of up to 130 ppbv and an ozone-enhanced layer depth of 10 km. We used Total Ozone Mapping Spectrometer, advanced very high resolution radiometer satellite image, and back air trajectory to identify the source region and the transport pattern of ozone. The strong tropospheric ozone enhancements covered all of tropical Southeast Asia and subtropical south China. They were due to photochemical ozone buildup from the biomass burning emissions from the Indonesian fires. The ozone-rich air mass was transported to Hong Kong following the east Asia local Hadley circulation and an abnormal anticyclonic flow related to the El Niño phenomenon in the tropical western Pacific. A rough estimation of the radiative forcing due to the ozone enhancement was carried out for two cases in October and December in 1997 using a normalized tropospheric ozone radiative forcing parameter derived from the Unified Chemistry-Climate model [Mickley et al., 1999]. The ozone enhancements induced an additional radiative forcing of 0.26 and 0.48 Wm-2 compared to the normal total forcing of 0.48 and 0.39 Wm-2 in October and December over the Hong Kong region. Estimation of the associated surface temperature change suggests that enhanced ozone from biomass burning on the scale of the 1997 Indonesian fires may have significant impact on regional surface temperature change.

  5. The effects of rapid urbanization on the levels in tropospheric nitrogen dioxide and ozone over East China

    NASA Astrophysics Data System (ADS)

    Huang, Jianping; Zhou, Chenhong; Lee, Xuhui; Bao, Yunxuan; Zhao, Xiaoyan; Fung, Jimmy; Richter, Andreas; Liu, Xiong; Zheng, Yiqi

    2013-10-01

    Over the past few decades, China has experienced a rapid increase in urbanization. The urban built-up areas (population) in Beijing, Shanghai, and Guangzhou increased by 197% (87%), 148% (65%), and 273% (25%), respectively, from 1996 to 2011. We use satellite retrieval data to quantify the effects of rapid urbanization on the yearly and seasonal changes in tropospheric nitrogen dioxide (NO2) over East China. The results show that rapid urbanization has a profound effect on tropospheric columns of NO2. During 1996-2011, the tropospheric columns of NO2 over the surrounding areas of Guangzhou, Shanghai, and Beijing increased by 82%, 292%, and 307%, respectively. The tropospheric columns of NO2 reach their maximum in winter and minimum in spring. The anthropogenic emissions related to urbanization are a dominant factor in the long-term changes in the yearly and seasonal mean tropospheric columns of NO2, whereas meteorological conditions such as the prevailing winds and precipitation account for the unique spatial patterns. Around the time of the 2008 Beijing Olympic Games, the tropospheric columns of NO2 over Beijing urban area significantly reduced by 48% in July, 35% in August, and 49% in September, relative to the same monthly averages over 2005-2007. However, this trend was reversed after the Games, and the increased rate was even larger than before. Our results show that the tropospheric NO2 above the three regions increased at rates 1.3-8 times faster than the rates in a recent inventory estimate of NOx emissions for 2000-2010. We also discuss the influence of urbanization on tropospheric ozone and find that the Ozone Monitoring Instrument (OMI) retrieval tropospheric column shows that ozone levels are relatively insensitive to urbanization and changes in tropospheric NO2.

  6. The Ecophysiology Of A Pinus Ponderosa Ecosystem Exposed To High Tropospheric Ozone: Implications For Stomatal And Non-Stomatal Ozone Fluxes

    NASA Astrophysics Data System (ADS)

    Fares, S.; McKay, M.; Goldstein, A.

    2008-12-01

    Ecosystems remove ozone from the troposphere through both stomatal and non-stomatal deposition. The portion of ozone taken up through stomata has an oxidative effect causing damage. We used a multi-year dataset to assess the physiological controls over ozone deposition. Environmental parameters, CO2 and ozone fluxes were measured continuously from January 2001 to December 2006 above a ponderosa pine plantation near Blodgett Forest, Georgetown, California. We studied the dynamic of NEE (Net Ecosystem Exchange, -838 g C m-2 yr-1) and water evapotranspiration on an annual and daily basis. These processes are tightly coupled to stomatal aperture which also controlled ozone fluxes. High levels of ozone concentrations (~ 100 ppb) were observed during the spring-summer period, with corresponding high levels of ozone fluxes (~ 30 μmol m-2 h-1). During the summer season, a large portion of the total ozone flux was due to non-stomatal processes, and we propose that a plant physiological control, releasing BVOC (Biogenic Volatile Organic Compounds), is mainly responsible. We analyzed the correlations of common ozone exposure metrics based on accumulation of concentrations (AOT40 and SUM0) with ozone fluxes (total, stomatal and non-stomatal). Stomatal flux showed poorer correlation with ozone concentrations than non-stomatal flux during summer and fall seasons, which largely corresponded to the growing period. We therefore suggest that AOT40 and SUM0 are poor predictors of ozone damage and that a physiologically based metric would be more effective.

  7. Autonomous Ozone and Aerosol LIDAR Profiling of the Troposphere: A Synergistic Approach

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.

    2015-12-01

    LIDAR technology is an excellent tool to probe the complex vertical structure of the atmosphere at high spatial and temporal resolution. This provides the critical vertical context for the interpretation of ground-based chemistry measurements, airborne measurements and model/satellite verification and validation. In recent years, Environment Canada has designed several autonomous aerosol LIDAR systems for deployment across several regions of Canada. The current system builds on the successes of these autonomous LIDARS but using a synergistic approach by combining tropospheric ozone DIAL (Differential Absorption LIDAR) technology with simultaneous 3+2+1 aerosol LIDAR measurements. It operates 24 hours a day, seven days a week except during precipitation events. The system is operated remotely and the data are updated every hour to a website to allow near real-time capability. A few case studies are shown emphasizing the synergistic approach of coupling ozone and aerosol profiles to better understand air quality impacts on local and regional scales.

  8. Characterizing tropospheric ozone and CO around Frankfurt between 1994-2012 based on MOZAIC-IAGOS aircraft measurements

    NASA Astrophysics Data System (ADS)

    Petetin, H.; Thouret, V.; Fontaine, A.; Sauvage, B.; Athier, G.; Blot, R.; Boulanger, D.; Cousin, J.-M.; Nedelec, P.

    2015-09-01

    In the framework of the MOZAIC-IAGOS program, ozone and carbon monoxide vertical profiles are available since 1994 and 2002, respectively. This study investigates the variability and trends of both species at several tropospheric layers above the Frankfurt and Munich airports where about 21 600 flights have been performed over the 1994-2012 period, which represents the densest dataset in the world (about 75 flights per month on average). Over that period, most mean ozone trends are positive but insignificant at a 95 % confidence level, except in winter where significant upward trends (around +0.38 ± 0.24 ppb yr-1) are found. Conversely, a significant increase of annual background ozone is highlighted, mostly during winter and autumn. Mean annual ozone trends increase with altitude, the largest increase being found in summer due to a noticeable decrease of highest ozone concentrations observed in the lower troposphere during the second half period. Over the 2002-2012 period, most mean CO trends are significantly negative, the decrease being higher in the lower troposphere compared to the mid- and upper troposphere with again, major differences in summer. Trends in the ozone seasonal cycle are also investigated, with a focus on the phase. Ozone maxima occur earlier and earlier with a shift around -10.6 ± 2.9 days decade-1 in the lower troposphere, in agreement with previous studies. The analysis of other ozone datasets in Europe (including surface stations and ozone soundings) confirms this trend, but highlights strong heterogeneities in the phase change. Interestingly, this shift is shown to decrease with altitude, with trends of -4.3 ± 2.4 and -2.0 ± 1.7 days decade-1 in the mid- and upper troposphere, respectively. The geographic origin of the air masses sampled by aircraft is analysed with FLEXPART backward simulations and suggests, together with trends and phase changes results, that an increase of the Asian contribution to ozone in the upper troposphere may

  9. Transport of tropospheric ozone and precursors to the Arctic: lessons from a multi-model evaluation using aircraft, satellite and surface data

    NASA Astrophysics Data System (ADS)

    Arnold, Steve; Monks, Sarah; Emmons, Louisa; Law, Kathy; Ridley, David; Turquety, Solene; Tilmes, Simone; Thomas, Jennie; Rap, Alex; Bouarar, Idir; Flemming, Johannes; Huijnen, Vincent; Mao, Jinqui; Duncan, Bryan; Steenrod, Stephen; Langner, Joakim; Long, Yoann

    2015-04-01

    Changes in abundances of short-lived climate pollutants such as tropospheric ozone and aerosol may have contributed significantly to observed rapid Arctic warming in recent decades. Ozone in the Arctic troposphere is influenced by long-range transport of polluted air from Europe, Asia and N. America, and in summer from boreal wildfires. Our understanding of how different sources contribute to Arctic tropospheric ozone is limited, and is reliant on sparse observations and models of atmospheric transport and chemistry. In particular, our confidence in future high latitude tropospheric ozone response to projected changes in mid-latitude emissions, and subsequent climate impacts, is informed by the ability of models to accurately simulate poleward export from source regions, long-range transport to high latitudes, and photochemical transformation of ozone and its precursors during such events. We will present an overview of recent results from the evaluation of simulated distributions of ozone and its precursors in the Arctic troposphere from 10 chemical transport models, using an extensive suite of in-situ aircraft data, and data from surface stations and satellites. The models show substantial variability in their ability to simulate abundances of key ozone precursor species throughout the depth of the Arctic troposphere, with implications for in-situ ozone photochemical production and loss. Using results from synthetic model tracer experiments, we separate the impacts of inter-model differences in transport and chemical processes in driving inter-model variability in high-latitude ozone precursor sensitivities to different anthropogenic and biomass burning source regions. We will also highlight the importance of simulated vertical export from source regions for the high latitude tropospheric ozone budget and ozone radiaitive effects. Finally, we discuss some important chemical uncertainties in simulating Arctic tropospheric ozone response to mid-latitude emissions

  10. A white clover system to estimate effects of tropospheric ozone on plants

    SciTech Connect

    Heagle, A.S.; Miller, J.E.; Sherrill, D.E.

    1994-05-01

    An ozone-sensitive (NC-S) and an ozone-resistant (NC-R) clone of white clover (Trifolium repens L.) were tested to determine the feasibility of using them to indicate concentrations of tropospheric ozone (O{sub 3}) and potential effects of O{sub 3} on plants. Plants of each clone were cloned daily in open-top field chambers to O{sub 3} concentrations ranging from 0.5 to 1.5 times the ambient concentrations for three summer seasons near Raleigh, NC. Foliar injury, foliar chlorophyll, and forage production of both clones were related directly to the O{sub 3} concentration. Ozone routinely injured leaves, suppressed foliar chlorophyll, and decreased growth of NC-S more than that of NC-R. Forage production was highly variable over a wide range of weather conditions, but the relative forage production rate of both clones under such conditions was similar and the seasonal O{sub 3} response relationship between NC-S and NC-R was relatively stable. The level of response of NC-S to O{sub 3} routinely increased from growth period to growth period suggesting an effect of previous exposure. More work is needed to calibrate the system over a wider range of ambient O{sub 3} levels and climatic conditions. 40 refs., 3 figs., 3 tabs.

  11. Dependence of Simulated Tropospheric Ozone Trends on Uncertainties in U.S. Mobile Fleet Emissions.

    NASA Astrophysics Data System (ADS)

    Monks, S. A.; Ryerson, T. B.; Emmons, L. K.; Tilmes, S.; Hassler, B.; Lamarque, J. F.

    2015-12-01

    Long-term surface observations show a rapid increase in background concentrations of ozone since the 1960s. Global chemistry-climate models have difficulties in reproducing this trend, overestimating the mid-century observed concentrations. This suggests that the impacts of ozone on climate and air quality throughout the second half of the 20th century may be misrepresented in current models. We use the MACCity emissions inventory constrained by ambient observations to examine the dependence of simulated long-term ozone trends on U.S. land transportation (mobile fleet) emissions of nitrogen oxides (NOX), carbon monoxide (CO) and volatile organic compounds (VOCs). Two sensitivity simulations are performed using the CAM-Chem chemical transport model, where the U.S. MACCity land transportation sector emissions of either NO or CO and co-emitted VOCs are constrained to the observed NO:CO ratio between 1960-2010. We present results from these sensitivity simulations to quantify the dependence of simulated background tropospheric ozone concentrations on these emissions.

  12. Seasonal behavior of tropospheric ozone in the Sao Paulo (Brazil) metropolitan area

    NASA Astrophysics Data System (ADS)

    Massambani, Oswaldo; Andrade, Fatima

    This paper presents a study of the seasonal behavior of tropospheric ozone and its precursors in the Sao Paulo Metropolitan Area as observed during 1987. The 03, NO, NO 2, NMHC, and meteorological data were collected at an air quality station in downtown Sao Paulo by the State Environmental Protection Agency (CETESB). The air pollutant measurements were related to both daily total insolation and the number of hours of insolation measured at the Sao Paulo University Climatological Station. Correlations between both radiation parameters and total daily integrated ozone amounts were performed. The total number of sunshine hours was highly correlated to mean hourly ozone concentration values during each month of 1987. The seasonal behavior of NO, NO 2, and NMHC was also studied. Two diurnal peaks in average NO concentration were observed, i.e. one in early morning and one in early evening; both were due to emissions from urban mobile sources. The magnitude of these peaks doubled in value during the winter months. Its diurnal concentration variation was inverse to that of the 03; similar behavior was found for NO 2 and for NMHC. The data presented herein show the influence of solar radiation and of ozone precursors on photochemical smog formation in this tropical region.

  13. Global 3-d modeling of atmospheric ozone in the free troposphere and the stratosphere with emphasis on midlatitude regions. Final report, July 1, 1994--June 30, 1997

    SciTech Connect

    Brasseur, G.; Erickson, D.; Tie, X.; Walter, S.

    1997-12-01

    The objective of this research is to use global chemical-transport models to study the chemical and dynamical processes that affect midlatitude stratospheric ozone and to quantify the budget of tropospheric ozone. Four models will be improved and used: (1) a new version of the two-dimensional chemical-radiative-dynamical model with microphysical process of sulfate aerosols and polar stratospheric clouds (PSCs), and heterogeneous conversions on the surfaces of sulfate aerosols and PSCs; (2) the stratospheric version of three-dimensional off-line chemical-transport model (STARS) with a relatively high horizontal resolution (2.8 degree in latitudes) with a microphysical formation of PSCs; (3) the tropospheric version of three-dimensional off-line chemical-transport model (MOZART) with details in the surface emissions and hydrocarbon reactions to estimate the tropospheric ozone budget and perturbations; (4) the intermediate model of the global and annual evolution of species (IMAGES) with a detailed chemical reactions but relatively lower resolutions. Model results will be compared with available data.

  14. Tentative critical levels of tropospheric ozone for agricultural crops in Japan

    NASA Astrophysics Data System (ADS)

    Yonekura, T.

    2010-12-01

    Ground level ozone concentrations have increased year by year in Japan. High ozone concentrations have been known to affect growth and yield of agricultural crops. In the US and Europe, much effort has been directed to establish regulatory policies such as secondary air quality standard and critical levels to protect vegetation against ozone. On the contrary, in Japan, there is a few data of agricultural crops sensitivity to ozone. Furthermore, there is no information about the ozone risk of agricultural crop loss by based on ozone index (e.g. AOT40, SUM06, W126)-crop response relationship, yet. The objects of our research are: (1) to screen sensitivity of ozone on 10 crops cultivated in urban area in Japan. (2) to establish critical levels of ozone for protecting agricultural crops based on ozone index-crop response relationship. The 10 Japanese agricultural crops such as Japanese rice, Hanegi (Welsh onion), Shungiku (Crown daisy), Saradana (Lettus), Hatsukadaikon (Radish), Kokabu (Small Turnip), Santosai (Chinese cabbage), Tasai (Spinach mustard), Komatsuna (Japanese mustard spinach) and Chingensai (Bok Choy), were fumigated to three levels of ozone (clean air (< 5 ppbv), ambient level of ozone, 1.5 times ambient ozone) in open-top chambers during 30 to 120 days. Those experiments were repeated five times during two growing season. Throughout the experimental period, the growth or yield were measured, and the relationship between growth (or yield) and ozone index was examined. As a result, the influences of ozone on growth or yield were different among 10 crops. Relatively good correlations of coefficients of determination (r2) for linear regressions to growth or yield were obtained with “8h means” and “AOT40” rather than “SUM00”, “SUM06” and “W126”. Critical level for 10 crops in terms of an AOT40 were 1.1 to 2.1 ppm h per month. The ozone sensitive crop in our study was sound to be 1.0 ppm h per month in AOT40.

  15. The SPARC Data Initiative: Comparison of upper troposphere/lower stratosphere ozone climatologies from limb-viewing instruments and the nadir-viewing Tropospheric Emission Spectrometer

    NASA Astrophysics Data System (ADS)

    Neu, J. L.; Hegglin, M. I.; Tegtmeier, S.; Bourassa, A.; Degenstein, D.; Froidevaux, L.; Fuller, R.; Funke, B.; Gille, J.; Jones, A.; Rozanov, A.; Toohey, M.; Clarmann, T.; Walker, K. A.; Worden, J. R.

    2014-06-01

    We present the first comprehensive intercomparison of currently available satellite ozone climatologies in the upper troposphere/lower stratosphere (UTLS) (300-70 hPa) as part of the Stratosphere-troposphere Processes and their Role in Climate (SPARC) Data Initiative. The Tropospheric Emission Spectrometer (TES) instrument is the only nadir-viewing instrument in this initiative, as well as the only instrument with a focus on tropospheric composition. We apply the TES observational operator to ozone climatologies from the more highly vertically resolved limb-viewing instruments. This minimizes the impact of differences in vertical resolution among the instruments and allows identification of systematic differences in the large-scale structure and variability of UTLS ozone. We find that the climatologies from most of the limb-viewing instruments show positive differences (ranging from 5 to 75%) with respect to TES in the tropical UTLS, and comparison to a "zonal mean" ozonesonde climatology indicates that these differences likely represent a positive bias for p ≤ 100 hPa. In the extratropics, there is good agreement among the climatologies regarding the timing and magnitude of the ozone seasonal cycle (differences in the peak-to-peak amplitude of <15%) when the TES observational operator is applied, as well as very consistent midlatitude interannual variability. The discrepancies in ozone temporal variability are larger in the tropics, with differences between the data sets of up to 55% in the seasonal cycle amplitude. However, the differences among the climatologies are everywhere much smaller than the range produced by current chemistry-climate models, indicating that the multiple-instrument ensemble is useful for quantitatively evaluating these models.

  16. Role of the boundary layer in the occurrence and termination of the tropospheric ozone depletion events in polar spring

    NASA Astrophysics Data System (ADS)

    Cao, Le; Platt, Ulrich; Gutheil, Eva

    2016-05-01

    Tropospheric ozone depletion events (ODEs) in the polar spring are frequently observed in a stable boundary layer condition, and the end of the events occurs when there is a breakup of the boundary layer. In order to improve the understanding of the role of the boundary layer in the ozone depletion event, a one-dimensional model is developed, focusing on the occurrence and the termination period of the ozone depletion episode. A module accounting for the vertical air transport is added to a previous box model, and a first-order parameterization is used for the estimation of the vertical distribution of the turbulent diffusivity. Simulations are performed for different strengths of temperature inversion as well as for different wind speeds. The simulation results suggest that the reactive bromine species released from the underlying surface into the lowest part of the troposphere initially stay in the boundary layer, leading to an increase of the bromine concentration. This bromine accumulation causes the ozone destruction below the top of the boundary layer. After the ozone is totally depleted, if the temperature inversion intensity decreases or the wind speed increases, the severe ozone depletion event tends to transit into a partial ozone depletion event or it recovers to the normal ozone background level of 30-40 ppb. This recovery process takes about 2 h. Due to the presence of high-level HBr left from the initial occurrence of ODEs, the complete removal of ozone in the boundary layer is achieved a few days after the first termination of ODE. The time required for the recurrence of the ozone depletion in a 1000 m boundary layer is approximately 5 days, while the initial occurrence of the complete ozone consumption takes 15 days. The present model is suitable to clarify the reason for both the start and the termination of the severe ozone depletion as well as the partial ozone depletion in the observations.

  17. Role of the boundary layer in the occurrence and termination of the tropospheric ozone depletion events in polar spring

    NASA Astrophysics Data System (ADS)

    Cao, Le; Platt, Ulrich; Gutheil, Eva

    2016-05-01

    Tropospheric ozone depletion events (ODEs) in the polar spring are frequently observed in a stable boundary layer condition, and the end of the events occurs when there is a breakup of the boundary layer. In order to improve the understanding of the role of the boundary layer in the ozone depletion event, a one-dimensional model is developed, focusing on the occurrence and the termination period of the ozone depletion episode. A module accounting for the vertical air transport is added to a previous box model, and a first-order parameterization is used for the estimation of the vertical distribution of the turbulent diffusivity. Simulations are performed for different strengths of temperature inversion as well as for different wind speeds. The simulation results suggest that the reactive bromine species released from the underlying surface into the lowest part of the troposphere initially stay in the boundary layer, leading to an increase of the bromine concentration. This bromine accumulation causes the ozone destruction below the top of the boundary layer. After the ozone is totally depleted, if the temperature inversion intensity decreases or the wind speed increases, the severe ozone depletion event tends to transit into a partial ozone depletion event or it recovers to the normal ozone background level of 30-40 ppb. This recovery process takes about 2 h. Due to the presence of high-level HBr left from the initial occurrence of ODEs, the complete removal of ozone in the boundary layer is achieved a few days after the first termination of ODE. The time required for the recurrence of the ozone depletion in a 1000 m boundary layer is approximately 5 days, while the initial occurrence of the complete ozone consumption takes 15 days. The present model is suitable to clarify the reason for both the start and the termination of the severe ozone depletion as well as the partial ozone depletion in the observations.

  18. Influence of future climate and cropland expansion on isoprene emissions and tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Squire, O. J.; Archibald, A. T.; Beerling, D.; Hewitt, C. N.; Lathiere, J.; Pike, R. C.; Telford, P.; Pyle, J. A.

    2013-12-01

    Over the 21st century, changes in CO2 levels, climate and land use are expected to alter the global distribution of vegetation, leading to changes in trace gas emissions from plants, including, importantly, the emissions of isoprene. This, combined with changes in anthropogenic emissions, has the potential to impact tropospheric ozone levels, which above a certain level are harmful to animals and vegetation. In this study we use a biogenic emissions model following the empirical parameterisation of the MEGAN model, with vegetation distributions calculated by the Sheffield Dynamic Global Vegetation Model (SDGVM) to calculate potential future (2095) changes in isoprene emissions caused by changes in climate, land use, and the inhibition of isoprene emissions by CO2. From the present day (2000) value of 467 Tg C yr-1, we find that the combined impact of these factors causes a net decrease in isoprene emissions of 259Tg C yr-1 (55%) with individual contributions of +78 Tg C yr-1 (climate change), -190 Tg C yr-1 (land use) and -147 Tg C yr-1 (CO2 inhibition). Using these isoprene emissions and changes in anthropogenic emissions, a series of integrations is conducted with the UM-UKCA chemistry-climate model with the aim of examining changes in ozone over the 21st century. Globally all combined future changes cause a decrease in the tropospheric ozone burden of 27 Tg (7%) from 379 Tg in the present day. At the surface, decreases in ozone of 6-10 ppb are calculated over the oceans and developed northern hemispheric regions due to reduced NOx transport by PAN and reductions in NOx emissions in these areas respectively. Increases of 4-6 ppb are calculated in the continental Tropics due to cropland expansion in these regions, increased CO2 inhibition of isoprene emissions, and higher temperatures due to climate change. These effects outweigh the decreases in tropical ozone caused by increased tropical isoprene emissions with climate change. Our land use change scenario

  19. A New Method of Deriving Time-Averaged Tropospheric Column Ozone over the Tropics Using Total Ozone Mapping Spectrometer (TOMS) Radiances: Intercomparison and Analysis Using TRACE A Data

    NASA Technical Reports Server (NTRS)

    Kim, J. H.; Hudson, R. D.; Thompson, A. M.

    1996-01-01

    Error analysis of archived total 03 from total ozone mapping spectrometer (TOMS) (version 6) presented. Daily total 03 maps for the tropics, from the period October 6-21, 1992, are derived from TOMS radiances following correction for these errors. These daily maps, averaged together, show a wavelike feature, which is observed in all latitude bands, underlying sharp peaks which occur at different longitudes depending on the latitude. The wave pattern is used to derive both time-averaged stratospheric and tropospheric 03 fields. The nature of the wave pattern (stratospheric or tropospheric) cannot be determined with certainty due to missing data (no Pacific sondes, no lower stratospheric Stratospheric Aerosol and Gas Experiment (SAGE) ozone for 18 months after the Mt. Pinatubo eruption) and significant uncertainties in the corroborative satellite record in the lower stratosphere (solar backscattered ultraviolet (SBUV), microwave limb sounder (MLS)). However, the time- averaged tropospheric ozone field, based on the assumption that the wave feature is stratospheric, agrees within 10% with ultraviolet differential absorption laser Transport and Atmospheric Chemistry near the Equator-Atlantic) (TRACE A) 03 measurements from the DC-8 and with ozonesonde measurements over Brazzaville, Congo, Ascension Island, and Natal, Brazil, for the period October 6-21, 1992. The derived background (nonpolluted) Indian Ocean tropospheric ozone amount, 26 Dobson units (DU), agrees with the cleanest African ozonesonde profiles for September-October 1992. The assumption of a totally tropospheric wave (flat stratosphere) gives 38 DU above the western Indian Ocean and 15-40% disagreements with the sondes. Tropospheric column 03 is high from South America to Africa, owing to interaction of dynamics with biomass burning emissions. Comparison with fire distributions from advanced very high resolution radiometer (AVHHR) during October 1992 suggests that tropospheric 03 produced from biomass

  20. Representation of the Bi-modal Distribution of Free Tropospheric Ozone Over the Tropical Western Pacific in CAM-CHEM

    NASA Astrophysics Data System (ADS)

    Honomichl, S.; Kinnison, D. E.; Lamarque, J. F.; Saiz-Lopez, A.; Randel, W. J.; Pan, L.

    2015-12-01

    During the CONTRAST field study, in situ aircraft observations revealed a distinct bi-modal distribution of ozone mixing ratios formed by persistent layers of enhanced of ozone relative to background concentrations in the Western Tropical Pacific middle troposphere during the Northern Hemispheric winter. These enhancements may have a measureable impact on the troposphere's oxidizing capacity in the tropics, which has a direct effect on the regional climate of the western tropical Pacific Ocean and beyond. In this work, we examine the representation of the bi-modal ozone characteristics in the NCAR chemistry-climate model (CAM-CHEM). We also investigate the controlling mechanisms of the bi-modal ozone distribution combining the model and aircraft observations.

  1. Transport of tropospheric and stratospheric ozone over India: Balloon-borne observations and modeling analysis

    NASA Astrophysics Data System (ADS)

    Sinha, P. R.; Sahu, L. K.; Manchanda, R. K.; Sheel, V.; Deushi, M.; Kajino, M.; Schultz, M. G.; Nagendra, N.; Kumar, P.; Trivedi, D. B.; Koli, S. K.; Peshin, S. K.; Swamy, Y. V.; Tzanis, C. G.; Sreenivasan, S.

    2016-04-01

    This study describes the spatio-temporal variation of vertical profiles of ozone (O3) measured by balloon-borne ozonesondes over two tropical sites of Trivandrum (TVM) and Hyderabad (HYD) in India from January 2009 to December 2010. In the lower troposphere, the mixing ratios of O3 over HYD (18-66 ppbv) were similar to TVM (18-65 ppbv). In the free troposphere, the O3 mixing ratios over HYD were higher than those over TVM throughout the year. In the tropical tropopause layer (TTL) region (above 15 km), the mixing ratios of O3 over TVM were higher (83-358 ppbv) compared to those measured over HYD (89-216 ppbv). Prevailing of O3 laminae between about 14 and 17 km is seen for both sites for most profiles. A strong seasonal variation of O3 is observed in the lower stratosphere between 18 and 24 km over TVM, however, it is not pronounced for HYD. Transport of air masses from the biomass burning region of the central Africa, Southeast Asia and the Indo Gangetic plains (IGP) influenced and led to enhancements of lower and mid-tropospheric O3 over HYD and TVM while, the isentropic (325 K) potential vorticity (PV) at 100 hPa showed transport of O3-rich air from the lower stratosphere to the upper troposphere during winter and spring months over both sites. The free tropospheric O3 mixing ratios (FT-O3; 0-4 km) contribute substantially to the tropospheric column O3 (TCO) with an annual average fraction of 30% and reveal the similar seasonal variations over HYD and TVM. The vertical profiles of O3 obtained from the Monitoring Atmospheric Composition and Climate - Interim Implementation (MACC-II) reanalysis and the Meteorological Research Institute-Chemistry Climate Model version 2 (MRI-CCM2) are compared with the ozonesonde data over both sites. The simulated magnitude, phase and vertical gradient of O3 from both MRI-CCM2 and MACC-II are in good agreement with measurements in the stratosphere while there are significant differences in the tropospheric columns.

  2. The detection of post-monsoon tropospheric ozone variability over south Asia using IASI data

    NASA Astrophysics Data System (ADS)

    Barret, B.; Le Flochmoen, E.; Sauvage, B.; Pavelin, E.; Matricardi, M.; Cammas, J. P.

    2011-03-01

    The ozone (O3) variability over south Asia during the 2008 post-monsoon season has been assessed using measurements from the MetOP-A/IASI instrument and O3 profiles retrieved with the SOftware for a Fast Retrieval of IASI Data (SOFRID). The information content study and error analyses carried out in this paper show that IASI Level 1 data can be used to retrieve tropospheric O3 columns (surface-225 hPa) and UTLS columns (225-70 hPa) with errors smaller than 20%. Validation with global radiosonde O3 profiles obtained during a period of 6 months show the excellent agreement between IASI and radiosonde for the UTLS with correlation coefficient R > 0.91 and good agreement in the troposphere with correlation coefficient R > 0.74. For both the UTLS and the troposphere Relative Standard Deviations (RSD) are lower than 23%. The temporal variability of the vertical profile of O3 has first been observed locally near Hyderabad in central India with in situ measurements from the MOZAIC program. These measurements obtained from airborne instruments show that tropospheric O3 is steadily elevated during most of the studied period with the exception of two sharp drops following the crossing of tropical storms over India. Lagrangian simulations with the FLEXPART model indicate that elevated O3 concentrations in the middle troposphere near Hyderabad are associated with the transport of UT air-masses that have followed the Subtropical Westerly Jet (SWJ) and subsided over northern India together with boundary layer polluted air-masses transported from the Indo-gangetic plain by the north-easterly trades. Low O3 concentrations result from the uplift and westward transport of pristine air-masses from the marine boundary layer of the Bay of Bengal by tropical storms. In order to extend the analysis of tropospheric O3 variability to the whole of south Asia, we have used IASI-SOFRID O3 data. We show that IASI O3 data around Hyderabad were able to capture the fast variability revealed by

  3. Nitrogen Oxides from Biogenic Alkyl Nitrates: A Natural Source of Tropospheric Ozone

    NASA Astrophysics Data System (ADS)

    Neu, J. L.; Lawler, M. J.; Saltzman, E. S.; Prather, M. J.

    2007-12-01

    Observations indicate that the tropical and southern oceans are source regions for biogenic emissions of alkyl nitrates. These compounds have lifetimes of several days to a month and are a significant source of reactive odd nitrogen (NOx) in remote regions of the atmosphere. These biogenically produced NOx precursors represent a natural control on atmospheric composition, including the important greenhouse gases methane (CH4) and tropospheric ozone (O3). We present simulations from the UCI global chemical transport model (CTM) using measurement-based fluxes of methyl and ethyl nitrate from their oceanic source regions and examine the contribution of these gases to global atmospheric composition. We also discuss the sensitivity of our results to our representation of two sub-gridscale processes: wet scavenging and photolysis in the presence of broken cloud fields. Quantification of the transport and chemistry of these compounds improves our understanding of natural tropospheric ozone production as well as hydroxyl radical (OH) chemistry in both the remote regions of the modern atmosphere and the pre-industrial atmosphere.

  4. Improved simulation of tropospheric ozone by a global-multi-regional two-way coupling model system

    NASA Astrophysics Data System (ADS)

    Yan, Y.-Y.; Lin, J.-T.; Chen, J.; Hu, L.

    2015-09-01

    Small-scale nonlinear chemical and physical processes over pollution source regions affect the global ozone (O3) chemistry, but these processes are not captured by current global chemical transport models (CTMs) and chemistry-climate models that are limited by coarse horizontal resolutions (100-500 km, typically 200 km). These models tend to contain large (and mostly positive) tropospheric O3 biases in the Northern Hemisphere. Here we use a recently built two-way coupling system of the GEOS-Chem CTM to simulate the global tropospheric O3 in 2009. The system couples the global model (at 2.5° long. × 2° lat.) and its three nested models (at 0.667° long. × 0.5° lat.) covering Asia, North America and Europe, respectively. Benefiting from the high resolution, the nested models better capture small-scale processes than the global model alone. In the coupling system, the nested models provide results to modify the global model simulation within respective nested domains while taking the lateral boundary conditions from the global model. Due to the "coupling" effects, the two-way system significantly improves the tropospheric O3 simulation upon the global model alone, as found by comparisons with a suite of ground (1420 sites from WDCGG, GMD, EMEP, and AQS), aircraft (HIPPO and MOZAIC), and satellite measurements (two OMI products). Compared to the global model alone, the two-way coupled simulation enhances the correlation in day-to-day variation of afternoon mean O3 with the ground measurements from 0.53 to 0.68, and it reduces the mean model bias from 10.8 to 6.7 ppb in annual average afternoon O3. Regionally, the coupled model reduces the bias by 4.6 ppb over Europe, 3.9 ppb over North America, and 3.1 ppb over other regions. The two-way coupling brings O3 vertical profiles much closer to the HIPPO (for remote areas) and MOZAIC (for polluted regions) data, reducing the tropospheric (0-9 km) mean bias by 3-10 ppb at most MOZAIC sites and by 5.3 ppb for HIPPO

  5. Tropospheric Ozone Increases in the TTL over the Southern African Region (1990-2007): Insights from Sonde and Aircraft Profiles

    NASA Astrophysics Data System (ADS)

    Balashov, N. V.; Thompson, A. M.; Kollonige, D. E.; Coetzee, G.; Thouret, V.; Posny, F.

    2013-12-01

    Ozonesonde records from the early 1990s through 2007 over two subtropical stations, Irene (near Pretoria, South Africa) and Réunion Island (21S, 55W, ~3500 km NE of Irene in the southwest Indian Ocean) have been reported to exhibit free tropospheric (FT) ozone increases. We re-analyzed FT ozone in the1990-2007 Irene sondes, filling in mid-1990s gaps with ozone profiles taken by Measurements of Ozone by Airbus In-service Aircraft (MOZAIC) over nearby Johannesburg. We applied a multivariate regression model to monthly averaged data from the combined dataset as well as to 1992-2011 FT and TTL ozone from Réunion sondes. Taking into account terms for the seasonal cycle, ENSO, and potential vorticity (PV) anomalies, we found that: (1) Statistically significant trends appear predominantly in the middle troposphere up to the tropopause layer (6-11 km over Irene, 6-15 km over Réunion) in winter (June-August), with an increase ~ 1 ppbv/yr over Irene and ~2 ppbv/yr over Réunion. Both stations display a less intense ozone increase above 7 km in November-December. (2) Variability in TTL dynamics and stratosphere-troposphere interactions were considered as plausible explanations for the Irene ozone increases. For the spring, there is a pronounced sensitivity to PV anomalies (+ 70 ppbv ozone/PV unit). We compare these results to our prior study of TTL wave activity at Irene and Réunion and relationships among waves, TTL ozone variability and oscillations like the ENSO. Trend (change in ppbv ozone/year) computed from multivariate regression model for 4-15 km, profiles from Réunion sondes, 1992-2011. Diagonal shading denotes statistical significance.

  6. CMAQ predictions of tropospheric ozone in the U.S. southwest: influence of lateral boundary and synoptic conditions.

    PubMed

    Shi, Chune; Fernando, H J S; Hyde, Peter

    2012-02-01

    Phoenix, Arizona, has been an ozone nonattainment area for the past several years and it remains so. Mitigation strategies call for improved modeling methodologies as well as understanding of ozone formation and destruction mechanisms during seasons of high ozone events. To this end, the efficacy of lateral boundary conditions (LBCs) based on satellite measurements (adjusted-LBCs) was investigated, vis-à-vis the default-LBCs, for improving the predictions of Models-3/CMAQ photochemical air quality modeling system. The model evaluations were conducted using hourly ground-level ozone and NO(2) concentrations as well as tropospheric NO(2) columns and ozone concentrations in the middle to upper troposphere, with the 'design' periods being June and July of 2006. Both included high ozone episodes, but the June (pre-monsoon) period was characterized by local thermal circulation whereas the July (monsoon) period by synoptic influence. Overall, improved simulations were noted for adjusted-LBC runs for ozone concentrations both at the ground-level and in the middle to upper troposphere, based on EPA-recommended model performance metrics. The probability of detection (POD) of ozone exceedances (>75ppb, 8-h averages) for the entire domain increased from 20.8% for the default-LBC run to 33.7% for the adjusted-LBC run. A process analysis of modeling results revealed that ozone within PBL during bulk of the pre-monsoon season is contributed by local photochemistry and vertical advection, while the contributions of horizontal and vertical advections are comparable in the monsoon season. The process analysis with adjusted-LBC runs confirms the contributions of vertical advection to episodic high ozone days, and hence elucidates the importance of improving predictability of upper levels with improved LBCs. PMID:22227303

  7. Satellite observation of lowermost tropospheric ozone by multispectral synergism of IASI thermal infrared and GOME-2 ultraviolet measurements

    NASA Astrophysics Data System (ADS)

    Cuesta, Juan; Eremenko, Maxim; Liu, Xiong; Dufour, Gaëlle; Cai, Zhaonan; Höpfner, Michael; von Clarmann, Thomas; Sellitto, Pasquale; Forêt, Gilles; Gaubert, Benjamin; Beekmann, Matthias; Orphal, Johannes; Chance, Kelly; Spurr, Robert; Flaud, Jean-Marie

    2013-04-01

    Lowermost tropospheric ozone is a major factor determining air quality in densely populated megacities. During pollution events, knowledge on the 3D regional distribution of ozone in and around these urban areas is key for assessing its impact on health of population and ecosystems damages. Temporal and spatial coverage of spaceborne observations are particularly fitted for monitoring tropospheric ozone spatial distribution at the regional scale and offers a great potential for improving air quality forecasting with numerical regional models. However, current tropospheric ozone retrievals using uncoupled either ultraviolet (UV) or thermal infrared (TIR) spaceborne observations show limited sensitivity to lowermost troposphere ozone (up to 3 km of altitude), which is the major concern for air quality, and they are mainly sensitive to ozone at the free Troposphere (at lowest 3-4 km of altitude). In this framework, we have developed a new multispectral approach for observing lowermost tropospheric ozone from space by synergism of atmospheric TIR radiances observed by IASI and earth UV reflectances measured by GOME-2. Both instruments are onboard the series of MetOp satellites (in orbit since 2006 and expected until 2022) and their scanning capabilities offer global coverage every day, with a relatively fine ground pixel resolution (12-km-diameter pixels spaced by 25 km for IASI at nadir). Our technique uses altitude-dependent Tikhonov-Phillips-type constraints, which optimize sensitivity to lower tropospheric ozone. It integrates the VLIDORT and KOPRA radiative transfer codes for simulating UV reflectance and TIR radiance, respectively. We have used our method to analyse real observations over Europe during an ozone pollution episode in the summer of 2009. The results show that the multispectral synergism of IASI (TIR) and GOME-2 (UV) enables the observation of the spatial distribution of ozone plumes in the lowermost troposphere (LMT, from the surface up to 3 km msl

  8. An Intercomparison of Tropospheric Ozone Retrievals Derived from Two Aura Instruments and Measurements in Western North America in 2006

    NASA Technical Reports Server (NTRS)

    Doughty, D. C.; Thompson, A. M.; Schoeberl, M. R.; Stajner, I.; Wargan, K.; Hui, W. C. J.

    2011-01-01

    Two recently developed methods for quantifying tropospheric ozone abundances based on Aura data, the Trajectory-enhanced Tropospheric Ozone Residual (TTOR) and an assimilation of Aura data into Goddard Earth Observing System Version 4 (ASM), are compared to ozone measurements from ozonesonde data collected in April-May 2006 during the INTEX Ozonesonde Network Study 2006 (IONS-06) campaign. Both techniques use Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) observations. Statistics on column ozone amounts for both products are presented. In general, the assimilation compares better to sonde integrated ozone to 200 hPa (28.6% difference for TTOR versus 2.7% difference for ASM), and both products are biased low. To better characterize the performance of ASM, ozone profiles based on the assimilation are compared to those from ozonesondes. We noted slight negative biases in the lower troposphere, and slight positive biases in the upper troposphere/lower stratosphere (UT/ LS), where we observed the greatest variability. Case studies were used to further understand ASM performance. We examine one case from 17 April 2006 at Bratt's Lake, Saskatchewan, where geopotential height gradients appear to be related to an underestimation in the ASM in the UT/LS region. A second case, from 21 April 2006 at Trinidad Head, California, is a situation where the overprediction of ozone in the UT/LS region does not appear to be due to current dynamic conditions but seems to be related to uncertainty in the flow pattern and large differences in MLS observations upstream.

  9. Influence of tropospheric ozone control on exposure to ultraviolet radiation at the surface.

    PubMed

    Madronich, Sasha; Wagner, Mark; Groth, Philip

    2011-08-15

    Improving air quality by reducing ambient ozone (O(3)) will likely lower O(3) concentrations throughout the troposphere and increase the transmission of solar ultraviolet (UV) radiation to the surface. The changes in surface UV radiation between two control scenarios (nominally 84 and 70 ppb O(3) for summer 2020) in the Eastern two-thirds of the contiguous U.S. are estimated, using tropospheric O(3) profiles calculated with a chemistry-transport model (Community Multi-Scale Air Quality, CMAQ) as inputs to a detailed model of the transfer of solar radiation through the atmosphere (tropospheric ultraviolet-visible, TUV) for clear skies, weighed for the wavelengths known to induce sunburn and skin cancer. Because the incremental emission controls differ according to region, strong spatial variability in O(3) reductions and in corresponding UV radiation increments is seen. The geographically averaged UV increase is 0.11 ± 0.03%, whereas the population-weighted increase is larger, 0.19 ± 0.06%, because O(3) reductions are greater in more densely populated regions. These relative increments in exposure are non-negligible given the already high incidence of UV-related health effects, but are lower by an order of magnitude or more than previous estimates. PMID:21755973

  10. Reactions of important OVOCs with hydrogen peroxide and ozone in the tropospheric aqueous phase

    NASA Astrophysics Data System (ADS)

    Schöne, Luisa; Weller, Christian; Herrmann, Hartmut

    2013-04-01

    Besides research on the microphysics of cloud droplets and similar aqueous systems in the troposphere, the chemistry of volatile organic compounds (VOCs) from anthropogenic and biogenic sources cannot be neglected for the understanding of tropospheric processes such as the organic particle mass formation. Emissions of biogenic volatile organic compounds (BVOCs) can exceed those of VOCs from anthropogenic sources by a factor of 10[1]. Oxidation products of BVOCs like glyoxal, methylglyoxal, glycolate, glyoxylate and pyruvate, glycolaldehyde, and the unsaturated compounds methacrolein and methyl vinyl ketone are known precursors for less volatile organic substances found in secondary organic aerosols[2,3]. Yet, the main decomposition of these substances is believed to occur via radical reactions. However, Tilgner and Herrmann[2] showed evidence that the turnovers by non-radical reactions with H2O2 or ozone and some non-oxidative organic accretion reactions may even exceed those from the most reactive species in the lower troposphere, the hydroxyl radical OH. This work investigated the reactivities of the atmospheric relevant oxidation products including pyruvic acid and glyoxylic acid towards O3 and H2O2 in the aqueous phase. Furthermore, pH effects were studied by measuring the kinetics of both the protonated and deprotonated forms. The measurements were performed using a UV/VIS-spectrometer (conventional and in addition a Stopped Flow technique) and capillary electrophoresis. In some cases the results indicate higher turnovers of H2O2 and ozone reactions compared to interactions with atmospheric radicals. The experimental data obtained will be presented and their implications for atmospheric multiphase chemistry are discussed. [1] Guenther et al., 1995, Journal of Geophysical Research - Atmosphere, 100(D5), 8873-8892. [2] Tilgner and Herrmann, 2010, Atmospheric Environment, 44, 5415-5422. [3] van Pinxteren et al., 2005, Atmospheric Environment, 39, 4305-4320.

  11. Harmonised Validation System for Tropospheric Ozone and Ozone Profile Retrievals from GOME to the Copernicus Sentinels

    NASA Astrophysics Data System (ADS)

    Keppens, A.; Lambert, J.-C.; Hubert, D.; Verhoelst, T.; Granville, J.; Ancellet, G.; Balis, D.; Delcloo, A.; Duflot, V.; Godin-Beekmann, S.; Leblanc, T.; Stavrakou, T.; Steinbrecht, W.; Stubi, R.; Thompson, A. M.

    2015-06-01

    This work outlines the principles and implementation procedures of a harmonised QA/validation system for assessing the quality of atmospheric composition data. The system now runs in pre-operational mode at BIRA-IASB, following a generic and fully traceable flow of operations. The system’s broad applicability to virtually all (partial) column and profile datasets is demonstrated here by evaluation activities within ESA’s Ozone_cci project. However, ozone data validation as envisaged in the upcoming S5PVT AO project “CHEOPS-5p” and for the future Copernicus Sentinel missions raises a number of additional challenges, foremost regarding the expected amount of data to be handled. We therefore provide a perspective on current developments of the validation system to address those challenges and make it evolve into a fast operational phase.

  12. Fluxes of BVOC and tropospheric ozone from a Citrus orchard in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Fares, S.; Park, J.; Weber, R.; Gentner, D. R.; Karlik, J. F.; Goldstein, A. H.

    2011-12-01

    Citrus plants, especially oranges, are widely cultivated in many countries experiencing Mediterranean climates. In many of these areas, orchards are often exposed to high levels of tropospheric ozone (O3) due to their location in polluted airsheds. Citrus take up O3 through their stomata and emit biogenic volatile organic compounds (BVOC), which can contribute to non-stomatal O3 removal through fast gas-phase reactions with O3. The study was performed in a valencia orange orchard in Exeter, California. From fall 2009 to winter 2010, CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously in situ with specific sensors (e.g. fast ozone analyzer and Proton Transfer Reaction Mass Spectrometer) using the eddy covariance techniques. Vertical concentration gradients of these compounds were also measured at 4 heights from the orchard floor to above the canopy. We observed high levels (up to 60 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 7 nmol m-2 s-1) followed by acetone. Monoterpenes fluxes were also recorded during the all vegetative period, with the highest emissions taking place during flowering periods, and in general highly temperature dependent. The orchard represented a sink for ozone, with uptake rates on the order of 10 nmol m-2 s-1 during the central hours of the day. We found that BVOC played a major role in removing ozone through chemical reactions in the gas-phase, while only up to 40 % of ozone was removed via stomatal uptake. The current research aimed at investigating the fate of BVOC emitted from orange trees will help understanding the role of Citrus orchards in the complex oxidation mechanisms taking place in the polluted atmosphere of the San Joaquin Valley (California).

  13. Role of carbonyls and aromatics in the formation of tropospheric ozone in Rio de Janeiro, Brazil.

    PubMed

    da Silva, Débora Bonfim Neves; Martins, Eduardo Monteiro; Corrêa, Sergio Machado

    2016-05-01

    The ozone in Rio de Janeiro has been in violation of national air quality standards. Among all of the monitoring stations, the Bangu neighbourhood has the most violations of the national standard of 160 μg m(-3) for the years 2012 and 2013. This study evaluated the reactivity of the carbonyls and aromatics in the tropospheric ozone formation processes. The samples were collected between July and October of 2013. Carbonyls were sampled using SiO2 cartridges coated with C18 and impregnated with 2,4-dinitrophenylhydrazine and were analysed by HPLC. Activated carbon cartridges and GC/MS were used to measure the concentration of monoaromatic hydrocarbons. An air quality monitoring station provided the concentrations of the criteria pollutants and the meteorological parameters. Cluster analysis and a Pearson correlation matrix were used to determine the formation of groups and the correlation of the variables. The evaluation of the volatile organic compounds (VOC) reaction with OH radicals and the MIR scale was used to extrapolate the reactivity of VOCs to the ozone formation. The average concentrations obtained were 19.7 and 51.9 μg m(-3) for formaldehyde and acetaldehyde, respectively. The mean concentrations obtained for aromatics were 1.5, 6.7, 1.5, 2.6 and 1.6 μg m(-3) for benzene, toluene, ethyl benzene, m+p-xylene and o-xylene, respectively. The cluster analysis indicated the presence of three similar groups, with one formed by gaseous criteria pollutants, another formed by the meteorological parameters, ozone and fine particles, and the last group formed by the aromatics. For the two reactivity scales evaluated, acetaldehyde and toluene were the main ozone precursors. PMID:27080853

  14. The Influence of the North Atlantic Oscillation on Tropospheric Distributions of Ozone and Carbon Monoxide.

    NASA Astrophysics Data System (ADS)

    Knowland, K. E.; Doherty, R. M.; Hodges, K.

    2015-12-01

    The influence of the North Atlantic Oscillation (NAO) on the tropospheric distributions of ozone (O3) and carbon monoxide (CO) has been quantified. The Monitoring Atmospheric Composition and Climate (MACC) Reanalysis, a combined meteorology and composition dataset for the period 2003-2012 (Innes et al., 2013), is used to investigate the composition of the troposphere and lower stratosphere in relation to the location of the storm track as well as other meteorological parameters over the North Atlantic associated with the different NAO phases. Cyclone tracks in the MACC Reanalysis compare well to the cyclone tracks in the widely-used ERA-Interim Reanalysis for the same 10-year period (cyclone tracking performed using the tracking algorithm of Hodges (1995, 1999)), as both are based on the European Centre for Medium-Range Weather Forecasts' (ECMWF) Integrated Forecast System (IFS). A seasonal analysis is performed whereby the MACC reanalysis meteorological fields, O3 and CO mixing ratios are weighted by the monthly NAO index values. The location of the main storm track, which tilts towards high latitudes (toward the Arctic) during positive NAO phases to a more zonal location in the mid-latitudes (toward Europe) during negative NAO phases, impacts the location of both horizontal and vertical transport across the North Atlantic and into the Arctic. During positive NAO seasons, the persistence of cyclones over the North Atlantic coupled with a stronger Azores High promotes strong horizontal transport across the North Atlantic throughout the troposphere. In all seasons, significantly more intense cyclones occur at higher latitudes (north of ~50°C) during the positive phase of the NAO and in the southern mid-latitudes during the negative NAO phase. This impacts the location of stratospheric intrusions within the descending dry airstream behind the associated cold front of the extratropical cyclone and the venting of low-level pollution up into the free troposphere within

  15. Impact of climate and land cover changes on tropospheric ozone air quality and public health in East Asia between 1980 and 2010

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Tai, A. P. K.

    2015-09-01

    Understanding how historical climate and land cover changes have affected tropospheric ozone in East Asia would help constrain the large uncertainties associated with future East Asian air quality projections. We perform a series of simulations using a global chemical transport model driven by assimilated meteorological data and a suite of land cover and land use data to examine the public health effects associated with changes in climate, land cover, land use, and anthropogenic emissions between the 5-year periods 1981-1985 and 2007-2011 in East Asia. We find that between these two periods land cover change alone could lead to a decrease in summertime surface ozone by up to 4 ppbv in East Asia and ~ 2000 fewer ozone-related premature deaths per year, driven mostly by enhanced dry deposition resulting from climate- and CO2-induced increase in vegetation density, which more than offsets the effect of reduced isoprene emission arising from cropland expansion. Climate change alone could lead to an increase in summertime ozone by 2-10 ppbv in most regions of East Asia and ~ 6000 more premature deaths annually, mostly attributable to warming. The combined impacts (-2 to +12 ppbv) show that while the effect of climate change is more pronounced, land cover change could offset part of the climate effect and lead to a previously unknown public health benefit. While the changes in anthropogenic emissions remain the largest contributor to deteriorating ozone air quality in East Asia over the past 30 years, we show that climate change and land cover changes could lead to a substantial modification of ozone levels, and thus should come into consideration when formulating future air quality management strategies. We also show that the sensitivity of surface ozone to land cover change is more dependent on dry deposition than on isoprene emission in most of East Asia, leading to ozone responses that are quite distinct from that in North America, where most ozone

  16. Free-Troposphere ozone and carbon monoxide over the North Atlantic for 2001-2011

    NASA Astrophysics Data System (ADS)

    Wu, Shiliang; Kumar, Aditya; Weise, Mark; Helmig, Detlev; Owen, R. Chris; Kramer, Louisa; Martin, Maria val; Palmer, Paul

    2013-04-01

    In-situ measurements of ozone (O3) and carbon monoxide (CO) over the mountaintop PICO-NARE station located in the Azores are analyzed together with results from atmospheric chemical transport modeling and satellite remote sensing data to examine the evolution of free-troposphere ozone and CO over the North Atlantic for 2001-2011. The GEOS-Chem chemical transport model captured the seasonal cycles for CO and O3 well but biased low for CO, particularly in springtime. Statistically significant (significance level of 0.05) decreasing trends were found for both O3 and CO based on statistic analysis of the observational data. The best estimates for the trends of ozone and CO are -0.2 and -0.3 ppbv/year respectively. These decreasing trends were confirmed with GEOS-Chem simulation results. These decreases have been partly attributed to the decreases in North American emissions over this period, which more than offset the impacts on North Atlantic background O3 and CO from emission increases in Asia. Additional factors including climate change that could potentially contribute to these trends are also explored through both statistical analysis and sensitivity model simulations.

  17. Lower tropospheric ozone and aerosol measurements at a coastal mountain site in Northern California

    NASA Astrophysics Data System (ADS)

    Post, A.; Conley, S. A.; Zhao, Y.; Cliff, S. S.; Faloona, I. C.; Wexler, A. S.; Lighthall, D.

    2012-12-01

    Increasing concern over the impacts of exogenous air pollution in California's Central Valley have prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County. Six months of ozone and aerosol measurements are presented in the context of long-range transport and its potential impact on surface air quality in the southern San Joaquin Valley. Moreover, approximately monthly ozone surveys are conducted by aircraft upwind, over the Pacific Ocean, and downwind, over the Central Valley, to characterize horizontal and vertical transport across the coastal mountains. The measurements exhibit no systematic diurnal variations of ozone or water vapor, an indication that the site primarily samples lower free tropospheric air which has not been significantly influenced by either local emissions or convective coupling to the surface. Aerosol size is measured with a scanning mobility particle sizer and composition is analyzed with an 8-stage rotating drum impactor whose substrates are characterized by X-ray fluorescence. Various elemental ratios and back trajectory calculations are used to infer the temporal patterns of influence that long range transport has on California air quality.

  18. Derivation of Tropospheric Column Ozone from the EPTOMS/GOES Co-Located Data Sets using the Cloud Slicing Technique

    NASA Technical Reports Server (NTRS)

    Ahn, C.; Ziemke, J. R.; Chandra, S.; Bhartia, P. K.

    2002-01-01

    A recently developed technique called cloud slicing used for deriving upper tropospheric ozone from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) instrument combined together with temperature-humidity and infrared radiometer (THIR) is no longer applicable to the Earth Probe TOMS (EPTOMS) because EPTOMS does not have an instrument to measure cloud top temperatures. For continuing monitoring of tropospheric ozone between 200-500hPa and testing the feasibility of this technique across spacecrafts, EPTOMS data are co-located in time and space with the Geostationary Operational Environmental Satellite (GOES)-8 infrared data for 2001 and early 2002, covering most of North and South America (45S-45N and 120W-30W). The maximum column amounts for the mid-latitudinal sites of the northern hemisphere are found in the March-May season. For the mid-latitudinal sites of the southern hemisphere, the highest column amounts are found in the September-November season, although overall seasonal variability is smaller than those of the northern hemisphere. The tropical sites show the weakest seasonal variability compared to higher latitudes. The derived results for selected sites are cross validated qualitatively with the seasonality of ozonesonde observations and the results from THIR analyses over the 1979-1984 time period due to the lack of available ozonesonde measurements to study sites for 2001. These comparisons show a reasonably good agreement among THIR, ozonesonde observations, and cloud slicing-derived column ozone. With very limited co-located EPTOMS/GOES data sets, the cloud slicing technique is still viable to derive the upper tropospheric column ozone. Two new variant approaches, High-Low (HL) cloud slicing and ozone profile derivation from cloud slicing are introduced to estimate column ozone amounts using the entire cloud information in the troposphere.

  19. Influence of isoprene chemical mechanism on modelled changes in tropospheric ozone due to climate and land use over the 21st century

    NASA Astrophysics Data System (ADS)

    Squire, O. J.; Archibald, A. T.; Griffiths, P. T.; Jenkin, M. E.; Pyle, J. A.

    2014-09-01

    Isoprene is a precursor to tropospheric ozone, a key pollutant and greenhouse gas. Anthropogenic activity over the coming century is likely to cause large changes in atmospheric CO2 levels, climate and land use, all of which will alter the global vegetation distribution leading to changes in isoprene emissions. Previous studies have used global chemistry-climate models to assess how possible changes in climate and land use could affect isoprene emissions and hence tropospheric ozone. The chemistry of isoprene oxidation, which can alter the concentration of ozone, is highly complex, therefore it must be parameterised in these models. In this work we compare the effect of four different reduced isoprene chemical mechanisms, all currently used in Earth-system models, on tropospheric ozone. Using a box model we compare ozone in these reduced schemes to that in a more explicit scheme (the MCM) over a range of NOx and isoprene emissions, through the use of O3 isopleths. We find that there is some variability, especially at high isoprene emissions, caused by differences in isoprene-derived NOx reservoir species. A global model is then used to examine how the different reduced schemes respond to potential future changes in climate, isoprene emissions, anthropogenic emissions and land use change. We find that, particularly in isoprene rich regions, the response of the schemes varies considerably. The wide ranging response is due to differences in the types of peroxy radicals produced by isoprene oxidation, and their relative rates of reaction towards NO, leading to ozone formation, or HO2, leading to termination. Also important is the yield of isoprene-nitrates and peroxyacyl nitrate precursors from isoprene oxidation. Those schemes that produce less of these NOx reservoir species, tend to produce more ozone locally and less away from the source region. Additionally, by combining the emissions and O3 data from all of the global model integrations, we are able to construct

  20. A Research Study of Tropospheric Ozone and Meteorological Parameters to Introduce High School Students to Scientific Procedures

    ERIC Educational Resources Information Center

    Diaz-de-Mera, Yolanda; Notario, Alberto; Aranda, Alfonso; Adame, Jose Antonio; Parra, Alfonso; Romero, Eugenio; Parra, Jesus; Munoz, Fernando

    2011-01-01

    An environmental research project was carried out by a consortium established among scientists and university lecturers in collaboration with two high schools. High school students participated in a long-term study of the local temporal profiles of tropospheric ozone and the relationship to pollution and meteorological parameters. Low-cost…

  1. Principal Component Analysis of Chlorophyll Content in Tobacco, Bean and Petunia Plants Exposed to Different Tropospheric Ozone Concentrations

    NASA Astrophysics Data System (ADS)

    Borowiak, Klaudia; Zbierska, Janina; Budka, Anna; Kayzer, Dariusz

    2014-06-01

    Three plant species were assessed in this study - ozone-sensitive and -resistant tobacco, ozone-sensitive petunia and bean. Plants were exposed to ambient air conditions for several weeks in two sites differing in tropospheric ozone concentrations in the growing season of 2009. Every week chlorophyll contents were analysed. Cumulative ozone effects on the chlorophyll content in relation to other meteorological parameters were evaluated using principal component analysis, while the relation between certain days of measurements of the plants were analysed using multivariate analysis of variance. Results revealed variability between plant species response. However, some similarities were noted. Positive relations of all chlorophyll forms to cumulative ozone concentration (AOT 40) were found for all the plant species that were examined. The chlorophyll b/a ratio revealed an opposite position to ozone concentration only in the ozone-resistant tobacco cultivar. In all the plant species the highest average chlorophyll content was noted after the 7th day of the experiment. Afterwards, the plants usually revealed various responses. Ozone-sensitive tobacco revealed decrease of chlorophyll content, and after few weeks of decline again an increase was observed. Probably, due to the accommodation for the stress factor. While during first three weeks relatively high levels of chlorophyll contents were noted in ozone-resistant tobacco. Petunia revealed a slow decrease of chlorophyll content and the lowest values at the end of the experiment. A comparison between the plant species revealed the highest level of chlorophyll contents in ozone-resistant tobacco.

  2. Characteristics of Perturbed Tropical Upper Tropospheric Ozone from SHADOZ (Southern Hemisphere Additional Ozonesondes) and pre-SHADOZ Soundings

    NASA Astrophysics Data System (ADS)

    Stone, J. B.; Thompson, A. M.; Lee, S.; Oltmans, S. J.; Solomon, S.; Witte, J. C.; Miller, S. K.; Schmidlin, F. J.

    2005-12-01

    SHADOZ (Southern Hemisphere Additional Ozonesondes) is part of Aura's constellation of validation efforts. Aura's interest in multi-instrument estimates of tropospheric ozone requires high-quality ozone measurements in the UT/LS. Within this region, primarily below 100 hPa, increases in the frequency of very low (< 20 ppbv) and near-zero ozone mixing ratios have been reported recently (Solomon et al, GRL, in press, 2005). These findings are based on ozone soundings at selected SHADOZ (1998-2004) stations where 1980's and early 1990's profiles are available. The location (preference for the western Pacific "warm pool" region) and morphology of these changes (100-300 hPa location in most cases) suggest perturbations in deep convection. Key meteorological variables corresponding to the low-ozone episodes are examined to evaluate potential processes related to change.

  3. Springtime daily variations in lower-tropospheric ozone over east Asia: the role of cyclonic activity and pollution as observed from space with IASI

    NASA Astrophysics Data System (ADS)

    Dufour, G.; Eremenko, M.; Cuesta, J.; Doche, C.; Foret, G.; Beekmann, M.; Cheiney, A.; Wang, Y.; Cai, Z.; Liu, Y.; Takigawa, M.; Kanaya, Y.; Flaud, J.-M.

    2015-09-01

    We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variations in lower-tropospheric ozone over east Asia. The availability of semi-independent columns of ozone from the surface up to 12 km simultaneously with CO columns provides a powerful observational data set to diagnose the processes controlling tropospheric ozone enhancement on synoptic scales. By combining IASI observations with meteorological reanalyses from ERA-Interim, we develop an analysis method based only on IASI ozone and CO observations to identify the respective roles of the stratospheric source and the photochemical source in ozone distribution and variations over east Asia. The succession of low- and high-pressure systems drives the day-to-day variations in lower-tropospheric ozone. A case study analysis of one frontal system and one cut-off low system in May 2008 shows that reversible subsiding and ascending ozone transfers in the upper-troposphere-lower-stratosphere (UTLS) region, due to the tropopause perturbations occurring in the vicinity of low-pressure systems, impact free and lower-tropospheric ozone over large regions, especially north of 40° N, and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible stratosphere-troposphere exchanges of ozone-rich air masses occur more locally in the southern and southeastern flanks of the trough. The contribution to the lower-tropospheric ozone column is difficult to dissociate from the tropopause perturbations generated by weather systems. For regions south of 40° N, a significant correlation has been found between lower-tropospheric ozone and carbon monoxide (CO) observations from IASI, especially over the North China Plain (NCP). Considering carbon monoxide observations as a pollutant tracer, the O3-CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such

  4. On the Tropospheric Measurements of Ozone by the Stratospheric Aerosol and Gas Experiment II (SAGE II, version 6.1) in the Tropics

    NASA Technical Reports Server (NTRS)

    Kar, J.; Trepte, C. R.; Thomason, L. W.; Zawodny, J. M.; Cunnold, D. M.; Wang, H. J.

    2002-01-01

    Tropospheric measurements of ozone from SAGE II (version 6.1) in the tropics have been analyzed using 12 years of data (1985-1990, 1994-1999). The seasonally averaged vertical profiles of the ozone mixing ratio in the upper troposphere have been presented for the first time from satellite measurements. These profiles show qualitative similarities with corresponding seasonal mean ozonesonde profiles at northern and southern tropical stations and are about 40-50% less than the sonde values. Despite this systematic offset, the measurements appear to be consistent with a zonal wave one pattern in the upper tropospheric column ozone and with the recently predicted summertime ozone enhancement over the Middle East. These results thus affirm the usefulness of the occultation method in studying tropospheric ozone.

  5. Laboratory studies of the sensitivity of tropospheric ozone to the chemistry of sea salt aerosol. Final report, September 15, 1993--September 14, 1994

    SciTech Connect

    Finlayson-Pitts, B.J.

    1994-11-15

    Ozone plays a critical role in both the chemistry and radiation balance of the troposphere. Understanding the factors controlling tropospheric ozone levels is critical to our understanding of a variety of issues in global chemistry and climate change. Chlorine atoms have the potential to contribute significantly to the ozone balance in the free troposphere. They can react directly with ozone or alternately, with organics and may actually lead to the formation of ozone in the presence of sufficient NO. Reactions of alkali halides in sea salt particles are a potential source of atomic chlorine, hence reactions of these alkali halides, especially those producing precursors to atomic chlorine, are of great interest. Finally, the mechanisms, intermediates and products of the Cl-biogenic reactions are unknown; these could serve as unique markers of chlorine atom chemistry in the troposphere, and hence are important to define.

  6. A model investigation of the impact of increases in anthropogenic NOx emissions between 1967 and 1980 on tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Dignon, J.; Hameed, S.

    1985-01-01

    The impact of anthropogenic NOx emission on tropospheric ozone has been investigated. Two statistical models were used for estimating annual global emissions of NOx and for driving the trend in the emission for the years 1966-1980. Both models show a steady increase in the NOx emission, except for two brief periods of leveling off: after 1973 and after 1978. The impact was estimated by calculating the rates of emissions as functions of latitude, longitude, and year, with a one-dimensional (latitudinal) model, which included coupled tropospheric photochemistry and diffusive meridional transport. Steady-state photochemical calculations with prescribed NOx emissions appropriate for 1966 and 1980 indicate an ozone increase of 8-11 percent in the Northern Hemisphere, a result compatible with the rise in ozone suggested by the observations.

  7. Variation of the NMVOC speciation in the solvent sector and the sensitivity of modelled tropospheric ozone

    NASA Astrophysics Data System (ADS)

    von Schneidemesser, E.; Coates, J.; Denier van der Gon, H. A. C.; Visschedijk, A. J. H.; Butler, T. M.

    2016-06-01

    Non-methane volatile organic compounds (NMVOCs) are detrimental to human health owing to the toxicity of many of the NMVOC species, as well as their role in the formation of secondary air pollutants such as tropospheric ozone (O3) and secondary organic aerosol. The speciation and amount of NMVOCs emitted into the troposphere are represented in emission inventories (EIs) for input to chemical transport models that predict air pollutant levels. Much of the information in EIs pertaining to speciation of NMVOCs is likely outdated, but before taking on the task of providing an up-to-date and highly speciated EI, a better understanding of the sensitivity of models to the change in NMVOC input would be highly beneficial. According to the EIs, the solvent sector is the most important sector for NMVOC emissions. Here, the sensitivity of modelled tropospheric O3 to NMVOC emission inventory speciation was investigated by comparing the maximum potential difference in O3 produced using a variety of reported solvent sector EI speciations in an idealized study using a box model. The sensitivity was tested using three chemical mechanisms that describe O3 production chemistry, typically employed for different types of modelling scales - point (MCM v3.2), regional (RADM2), and global (MOZART-4). In the box model simulations, a maximum difference of 15 ppbv (ca. 22% of the mean O3 mixing ratio of 69 ppbv) between the different EI speciations of the solvent sector was calculated. In comparison, for the same EI speciation, but comparing the three different mechanisms, a maximum difference of 6.7 ppbv was observed. Relationships were found between the relative contribution of NMVOC compound classes (alkanes and oxygenated species) in the speciations to the amount of Ox produced in the box model. These results indicate that modelled tropospheric O3 is sensitive to the speciation of NMVOCs as specified by emission inventories, suggesting that detailed updates to the EI speciation

  8. The 'Weekend Effect' in Tropospheric NO2 Seen from the Ozone Monitoring Instrument

    NASA Technical Reports Server (NTRS)

    Bucsela, E.; Wenig, M.; Celarier, E.; Gleason, J.

    2007-01-01

    The Ozone Monitoring Instrument has gathered daily global data on NO2 and other atmospheric trace gases since its launch on the EOS Aura satellite in 2004. The large accumulated data set makes it possible to monitor changes of both meteorological and anthropogenic origin in tropospheric NOz amounts. In particular, averages on time scales on the order of a year show a distinct 'weekend effect' in NO2 variation, with smaller NO2 amounts seen on Saturday and/or Sunday than on the remaining weekdays. Using the OMI NO2 Standard Product (SP), we examine this effect in relation to geopolitical boundaries and investigate implications for identifying sources. We also use the SP data to find evidence for other short-term anthropogenic changes in NO2 emissions over heavily polluted regions including the United States, Europe and China.

  9. Lower tropospheric ozone and aerosol measurements at a coastal mountain site in Central California

    NASA Astrophysics Data System (ADS)

    Post, A.; Faloona, I. C.; Lighthall, D.; Wexler, A. S.; Cliff, S. S.; Conley, S. A.; Zhao, Y.

    2013-12-01

    Increasing concern over the impacts of exogenous air pollution in California's Central Valley has prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County, operated by the Monterey Institute for Research in Astronomy. Eighteen months of ozone and aerosol measurements are presented in the context of long-range transport and its potential impact on surface air quality in the southern San Joaquin Valley. Moreover, several ozone surveys have been conducted by aircraft upwind, over the Pacific Ocean, and downwind, over the Central Valley, to characterize horizontal and vertical transport across the coastal mountains. Diurnal variations present at Chews Ridge indicate the formation of a convective boundary layer on the ridge during the daytime leading to a 6-8 ppb decrease in ozone accompanied by a rise in specific humidity of 2-3 g/kg due to coupling with the forest. During the nighttime, the sampled air masses are representative of free tropospheric conditions which have not been significantly influenced by either local emissions nor convective coupling to the surface. The maximum daily 8-hour average ozone concentration at Chews Ridge is used in lagged correlation analysis with two sites in the San Joaquin Valley, Fresno and Arvin, to de-emphasize the influence of locally produced, diurnally cycled ozone. The correlation coefficients (~0.60) peak between 9-21 hour lag and tend to decorrelate completely within 4-5 days. These and other analyses along with data provided by the aircraft sampling are used to provide a deeper understanding of ozone transport into the San Joaquin Valley. Aerosol size is measured with a scanning mobility particle sizer and composition is analyzed with an 8-stage rotating drum impactor whose substrates are characterized by X-ray fluorescence. Various elemental ratios and back trajectory calculations are used to infer the temporal

  10. Pronounced Minima in Tropospheric Ozone and OH above the Tropical West Pacific and their Role for Stratospheric Composition

    NASA Astrophysics Data System (ADS)

    Rex, M.; Wohltmann, I.; Lehmann, R.; Rosenlof, K. H.; Wennberg, P. O.; Weisenstein, D. K.; Notholt, J.; Krüger, K.; Mohr, V.; Tegtmeier, S.

    2014-12-01

    Hundreds of organic species are emitted into the atmosphere mostly from biogenic processes. The rapid breakdown by reactions with OH radicals prevents most of them from reaching the stratosphere. Hence, the omnipresent layer of OH in the troposphere shields the stratosphere from these emissions and is particularly relevant for those species that do not photolyse efficiently. Reactions involving ozone are a strong source of OH in clean tropical air. Hence the OH concentration is closely coupled to ozone abundances. The Western Pacific warm pool is key for troposphere to stratosphere exchange. We report measurements of 14 ozonesondes launched during the Transbrom ship cruise through the center of the warm pool. During a 2500km portion of the ship track between 10S and 15N we found ozone concentrations below the detection limit of the sondes throughout the troposphere. We will discuss the uncertainties of ozonesonde measurements at very low ozone concentrations, the robustness of our observations and the upper limit of the ozone concentration that would be consistent with our raw data. Based on modelling and measurements of OH on the ER-2 during the STRAT campaign we suggest that there also is a pronounced minimum in the tropospheric column of OH over the tropical West Pacific. We show that this increases the lifetime of chemical species and has the potential to amplify the impact of surface emissions on the stratospheric composition. Specifically, we discuss the role of emissions of biogenic halogenated species from this geographic region for stratospheric ozone depletion. Also, we discuss the potential role of increasing anthropogenic emissions of SO2 in South East Asia or from minor volcanic eruptions for the stratospheric aerosol budget.

  11. Highlights from the 11-Year Record of Tropospheric Ozone from OMI/MLS and Continuation of that Long Record Using OMPS Measurements

    NASA Technical Reports Server (NTRS)

    Ziemke, J. R.; Kramarova, N. A.; Bhartia, P. K.; Degenstein, D. A.; Deland, M. T.

    2016-01-01

    Since October 2004 the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) onboard the Aura satellite have provided over 11 years of continuous tropospheric ozone measurements. These OMI/MLS measurements have been used in many studies to evaluate dynamical and photochemical effects caused by ENSO, the Madden-Julian Oscillation (MJO) and shorter timescales, as well as long-term trends and the effects of deep convection on tropospheric ozone. Given that the OMI and MLS instruments have now extended well beyond their expected lifetimes, our goal is to continue their long record of tropospheric ozone using recent Ozone Mapping Profiler Suite (OMPS) measurements. The OMPS onboard the Suomi National Polar-orbiting Partnership NPP satellite was launched on October 28, 2011 and is comprised of three instruments: the nadir mapper, the nadir profiler, and the limb profiler. Our study combines total column ozone from the OMPS nadir mapper with stratospheric column ozone from the OMPS limb profiler to measure tropospheric ozone residual. The time period for the OMPS measurements is March 2012 present. For the OMPS limb profiler retrievals, the OMPS v2 algorithm from Goddard is tested against the University of Saskatchewan (USask) Algorithm. The retrieved ozone profiles from each of these algorithms are evaluated with ozone profiles from both ozonesondes and the Aura Microwave Limb Sounder (MLS). Effects on derived OMPS tropospheric ozone caused by the 2015-2016 El Nino event are highlighted. This recent El Nino produced anomalies in tropospheric ozone throughout the tropical Pacific involving increases of approximately 10 DU over Indonesia and decreases approximately 5-10 DU in the eastern Pacific. These changes in ozone due to El Nino were predominantly dynamically-induced, caused by the eastward shift in sea-surface temperature and convection from the western to the eastern Pacific.

  12. Highlights from the 11-year record of tropospheric ozone from OMI/MLS and continuation of that long record using OMPS measurements

    NASA Astrophysics Data System (ADS)

    Ziemke, Jerry; Kramarova, Natalya; Bhartia, Pawan; Degenstein, Doug; Deland, Matthew

    2016-04-01

    Since October 2004 the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) onboard the Aura satellite have provided over 11 years of continuous tropospheric ozone measurements. These OMI/MLS measurements have been used in many studies to evaluate dynamical and photochemical effects caused by ENSO, the Madden-Julian Oscillation (MJO) and shorter timescales, as well as long-term trends and the effects of deep convection on tropospheric ozone. Given that the OMI and MLS instruments have now extended well beyond their expected lifetimes, our goal is to continue their long record of tropospheric ozone using recent Ozone Mapping Profiler Suite (OMPS) measurements. The OMPS onboard the Suomi National Polar-orbiting Partnership NPP satellite was launched on October 28, 2011 and is comprised of three instruments: the nadir mapper, the nadir profiler, and the limb profiler. Our study combines total column ozone from the OMPS nadir mapper with stratospheric column ozone from the OMPS limb profiler to measure tropospheric ozone residual. The time period for the OMPS measurements is March 2012 - present. For the OMPS limb profiler retrievals, the OMPS v2 algorithm from Goddard is tested against the SASKatchewan radiative TRANsfer (SASKTRAN) algorithm. The retrieved ozone profiles from each of these algorithms are evaluated with ozone profiles from both ozonesondes and the Aura Microwave Limb Sounder (MLS). Effects on derived OMPS tropospheric ozone caused by the 2015-2016 El Nino event are highlighted. This recent El Nino produced anomalies in tropospheric ozone throughout the tropical Pacific involving increases of ~10 DU over Indonesia and decreases ~5-10 DU in the eastern Pacific. These changes in ozone due to El Nino were predominantly dynamically-induced, caused by the eastward shift in sea-surface temperature and convection from the western to the eastern Pacific.

  13. Time and Spatially Dependent Estimates of Pollutant Trace Gas Emissions and Their Effect on Tropospheric Ozone

    NASA Astrophysics Data System (ADS)

    Dignon, Jane Elizabeth

    Statistical models have been developed to relate the rate of pollutant emissions from fossil fuel combustion to the rate of fuel consumption. These models have been used to estimate global emissions of nitrogen and sulfur oxides in fossil fuel combustion since the year 1860. When averaged over the 1860 to 1980 period, global sulfur emissions increased at a rate of 2.9 percent per year, and the nitrogen emissions increased a rate of 3.4 percent per year. Using these statistical models along with population distribution estimates, high resolution geographical maps of emissions can be produced for each year which fuel consumption data are available. Global emissions of NO_ {x} and SO_{x} emissions for 1966 and 1980 are illustrated on a latitude-longitude grid appropriate for general circulation models of the atmosphere. Emissions of carbon monoxide from fossil fuel, wood and biomass fuel, and open burning of vegetation, as well as emissions of nitrogen and sulfur oxides from wood and biomass fuel burning, are estimated for 1980 using emission factor methods. These trace gas sources are also mapped globally. The impact of increasing emissions of NO _{x} on tropospheric ozone abundance is estimated by calculations with a one-dimensional (latitudinal) model which includes coupled tropospheric photo-chemistry and diffusive meridional transport. Steady-state photochemical calculations with the prescribed NO_{x } emissions appropriate for 1966 and 1980 indicate an ozone increase of 8 to 11 percent in the Northern Hemisphere, a result which is compatible with the rise of about 12 percent between 1970 and 1981 suggested by recent observations.

  14. Tropospheric ozone and aerosols measured by airborne lidar during the 1988 Arctic boundary layer experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.

  15. Observing lowermost tropospheric ozone pollution with a new multispectral synergic approach of IASI infrared and GOME-2 ultraviolet satellite measurements

    NASA Astrophysics Data System (ADS)

    Cuesta, Juan; Foret, Gilles; Dufour, Gaëlle; Eremenko, Maxim; Coman, Adriana; Gaubert, Benjamin; Beekmann, Matthias; Liu, Xiong; Cai, Zhaonan; Von Clarmann, Thomas; Spurr, Robert; Flaud, Jean-Marie

    2014-05-01

    Tropospheric ozone is currently one of the air pollutants posing greatest threats to human health and ecosystems. Monitoring ozone pollution at the regional, continental and global scale is a crucial societal issue. Only spaceborne remote sensing is capable of observing tropospheric ozone at such scales. The spatio-temporal coverage of new satellite-based instruments, such as IASI or GOME-2, offer a great potential for monitoring air quality by synergism with regional chemistry-transport models, for both inter-validation and full data assimilation. However, current spaceborne observations using single-band either UV or IR measurements show limited sensitivity to ozone in the atmospheric boundary layer, which is the major concern for air quality. Very recently, we have developed an innovative multispectral approach, so-called IASI+GOME-2, which combines IASI and GOME-2 observations, respectively in the IR and UV. This unique multispectral approach has allowed the observation of ozone plumes in the lowermost troposphere (LMT, below 3 km of altitude) over Europe, for the first time from space. Our first analyses are focused on typical ozone pollution events during the summer of 2009 over Europe. During these events, LMT ozone plumes at different regions are produced photo-chemically in the boundary layer, transported upwards to the free troposphere and also downwards from the stratosphere. We have analysed them using IASI+GOME-2 observations, in comparison with single-band methods (IASI, GOME-2 and OMI). Only IASI+GOME-2 depicts ozone plumes located below 3 km of altitude (both over land and ocean). Indeed, the multispectral sensitivity in the LMT is greater by 40% and it peaks at 2 to 2.5 km of altitude over land, thus at least 0.8 to 1 km below that for all single-band methods. Over Europe during the summer of 2009, IASI+GOME-2 shows 1% mean bias and 21% precision for direct comparisons with ozonesondes and also good agreement with CHIMERE model simulations

  16. SHADOZ (Southern Hemisphere ADditional Ozonesondes}: What Have We Learned About Tropical Tropospheric Ozone from the First Three Years (1998-2000) Data

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The first climatological overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropical and subtropics is based on ozone sounding data from 10 sites comprising the Southern Hemisphere Additional OZonesondes (SHADOZ) network. The period covered is 1998-2000. Observations were made over: Ascension Island; Nairobi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil. Campaign data were collected on an Trans-Atlantic oceanographic cruise and during SAFARI-2000 in Zambia. The ozone data, with simultaneous temperature profiles to approximately 7 hPa and relative humidity to approximately 200 hPa, reside at: . SHADOZ ozone time-series and profiles give a perspective on tropical total, stratospheric and tropospheric ozone in 1998-2000. Prominent features are highly variable tropospheric ozone, a zonal wave-one pattern in total (and tropospheric) column ozone, and signatures of the Quasi-Biennial Oscillation (QBO) in stratospheric ozone. Total, stratospheric and tropospheric column ozone amounts peak between August and November and are lowest between March and May. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the Indian Ocean Dipole, and convective mixing. Pollution transport from Africa, South American and the Maritime Continent is a seasonal feature. Tropospheric ozone seasonality over the Atlantic Basin shows effects of regional subsidence and recirculation as well as biomass burning. Dynamical and chemical influences appear to be of comparable magnitude though model studies are needed to quantify this.

  17. SHADOZ (Southern Hemisphere ADditional Ozonesondes): What Have We Learned About Tropical Tropospheric Ozone from the First Three Years' (1998-2000) Data?

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Bhartia, Pawan (Technical Monitor)

    2002-01-01

    The first climatological overview of total, stratospheric and tropospheric ozone in the southern hemisphere tropical and subtropics is based on ozone sounding data from 10 sites comprising the Southern Hemisphere Additional OZonesondes (SHADOZ) network. The period covered is 1998-2000. Observations were made over: Ascension Island; Nairobi, Kenya; Irene, South Africa; RCunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; Natal, Brazil. Campaign data were collected on a trans-Atlantic oceanographic cruise and during SAFARI-2000 in Zambia. The ozone data, with simultaneous temperature profiles to approx. 7 hPa and relative humidity to approx. 200 hPa, reside at: . SHADOZ ozone time-series and profiles give a perspective on tropical total, stratospheric and tropospheric ozone in 1998-2000. Prominent features are highly variable tropospheric ozone, a zonal wave-one pattern in total (and tropospheric) column ozone, and signatures of the Quasi-Biennial Oscillation (QBO) in stratospheric ozone. Total, stratospheric and tropospheric column ozone amounts peak between August and November and are lowest between March and May. Tropospheric ozone variability over the Indian and Pacific Ocean displays influences of the Indian Ocean Dipole, and convective mixing. Pollution transport from Africa, South American and the Maritime Continent is a seasonal feature. Tropospheric ozone seasonality over the Atlantic Basin shows effects of regional subsidence and recirculation as well as biomass burning. Dynamical and chemical influences appear to be of comparable magnitude though model studies are needed to quantify this.

  18. Ozone production in the upper troposphere over West Africa: sensitivity to non-methane hydrocarbons under convective conditions

    NASA Astrophysics Data System (ADS)

    Bechara, Joelle; Borbon, Agnès.; Aumont, Bernard; Jambert, Corinne; Perros, Pascal

    2010-05-01

    Tropical deep convection is an efficient pathway of transporting up to the upper troposphere (UT) trace gas species such as volatile organic compounds (VOC). However, the impact of convective transport on UT composition and chemistry is still poorly characterized. The chemical impact of convection on the tropical UT over West Africa was studied during the AMMA Special Observation Period in August 2006 (SOP 2a2). Experimental strategy consisted in sampling at altitudes between 0 and 12 km downwind of Mesoscale Convective Systems (MCS) and at cloud base on-board the two French aircrafts, the ATR-42 and the French Falcon-20. Previous work pointed out that tropical deep convection in West Africa is efficient and is responsible with fast transport of VOC into the UT even the most reactive (isoprene) in less than one hour (Bechara et al., 2009). Here, we have investigated the impact of VOC precursors on ozone production. For that purpose, box modelling was implemented with the Master Chemical Mechanism scheme to simulate ozone variability in the upper troposphere downwind convection. The model is initialized with observed trace gases concentrations (NMHC, NOx, NOy, CO...) collected during the AMMA SOP 2a2 airborne campaign. Results show a positive ozone production several days downwind convective clouds at an average rate of 4 ppb/day. They confirm that UT ozone production is sensitive to NOx. Surprisingly, the sensitivity of NMHC initial concentrations on ozone production is negative. Indeed, an increase in NMHC favours PAN (peroxyacetyl nitrate) formation and thus decreases ozone production. The implication on ozone budget in the upper troposphere is crucial.

  19. Observed seasonal cycles in tropospheric ozone at three marine boundary layer locations and their comparison with models

    NASA Astrophysics Data System (ADS)

    Derwent, Richard

    2016-04-01

    Observational data have been used to define the seasonal cycles in tropospheric ozone at the surface at three marine boundary layer (MBL) locations at Mace Head in Ireland, Trinidad Head in the USA and at Cape Grim in Tasmania. Least-squares fits of a sine function to the observed monthly mean ozone mixing ratios allowed ozone seasonal cycles to be defined quantitatively, as follows: y = Y0 + A1 sin(θ + φ1) + A2 sin(2θ + φ2), where Y0 is the annual average ozone mixing ratio over the entire set of observations or model results, A1 and A2 are amplitudes, φ1 and φ2 are phase angles and θ is a variable that spans one year's time period in radians. The seasonal cycles of fourteen tropospheric ozone models, together with our own STOCHEM-CRI model, at the three MBL stations were then analysed by fitting sine curves and defining the five parameters: Y0, A1, φ1, A2, φ2. Compared to the fundamental term: A1 sin(θ + φ1), all models more accurately reproduced the observed second harmonic terms: A2 sin(2θ + φ2). This accurate agreement both in amplitude and phase angle suggested that the term arose from a cyclic phenomenon that was well predicted by all models, namely, the photochemical destruction of ozone. Model treatments of the fundamental term were in many cases far removed from the observations and it was not clear why there was so much variability across the tropospheric ozone models.

  20. Tropospheric ozone and nitrogen dioxide measurements in urban and rural regions as seen by IASI and GOME-2

    NASA Astrophysics Data System (ADS)

    Safieddine, S.; Clerbaux, C.; George, M.; Hadji-Lazaro, J.; Hurtmans, D.; Coheur, P.-F.; Wespes, C.; Loyola, D.; Valks, P.; Hao, N.

    2013-09-01

    ozone (O3) columns in urban and rural regions as seen by the Infrared Atmospheric Sounding Interferometer (IASI) are analyzed along with the Global Ozone Monitoring Experiment (GOME-2) tropospheric nitrogen dioxide (NO2) columns. Results over nine cities of the Northern Hemisphere for the period 2008-2011 show a typical seasonal behavior of tropospheric O3, with a first maximum reached in late spring because of stratospheric intrusion mainly and a continuous rise till the summer because of the anthropogenic-based ozone production. Over the East Asian cities, a decrease in the O3 tropospheric column is detected during the monsoon period. Seasonal cycling of tropospheric NO2 shows consistent higher values during winter because of the higher anthropogenic sources and longer lifetime. In rural regions, a complex relation between the O3 and NO2 columns is found, with good correlation in summer and winter. O3 concentrations in rural sites are found to be comparable to those closest to the anthropogenic emission sources, with peak values in spring and summer. Furthermore, the effect of the reduction of pollutant emissions in the Beijing region during the Olympic Games of 2008 compared to the same summer period in the following 3 years is studied. GOME-2 NO2 measurements show a reduction up to 54% above Beijing during this period compared to the following 3 years. IASI O3 measurements show an increase of 12% during July 2008 followed by a decrease of 5-6% during the months of August and September.

  1. The detection of post-monsoon tropospheric ozone variability over south Asia using IASI data

    NASA Astrophysics Data System (ADS)

    Barret, B.; Le Flochmoen, E.; Sauvage, B.; Pavelin, E.; Matricardi, M.; Cammas, J. P.

    2011-09-01

    The ozone (O3) variability over south Asia during the 2008 post-monsoon season has been assessed using measurements from the MetOP-A/IASI instrument and O3 profiles retrieved with the SOftware for a Fast Retrieval of IASI Data (SOFRID). The information content study and error analyses carried out in this paper show that IASI Level 1 data can be used to retrieve tropospheric O3 columns (TOC, surface-225 hPa) and UTLS columns (225-70 hPa) with errors smaller than 20%. Validation with global radiosonde O3 profiles obtained during a period of 6 months show the excellent agreement between IASI and radiosonde for the UTLS with correlation coefficient R > 0.91 and good agreement in the troposphere with correlation coefficient R > 0.74. For both the UTLS and the troposphere Relative Standard Deviations (RSD) are lower than 23%. Comparison with in-situ measurements from the MOZAIC program around Hyderabad demonstrates that IASI is able to capture the TOC inter and intra-seasonal variability in central India. Nevertheless, the agreement is mitigated by the fact that the smoothing of the true O3 profiles by the retrieval results in a reduction of the TOC variability detected by IASI relative to the variability observed by in situ instruments. The post-monsoon temporal variability of the vertical profile of O3 around Hyderabad has been investigated with MOZAIC observations. These observations from airborne instruments show that tropospheric O3 is steadily elevated during most of the studied period with the exception of two sharp drops following the crossing of tropical storms over India. Lagrangian simulations with the FLEXPART model indicate that elevated O3 concentrations in the middle troposphere near Hyderabad are associated with the transport of UTLS air-masses that have followed the Subtropical Westerly Jet (SWJ) and subsided over northern India together with boundary layer polluted air-masses transported from the Indo-gangetic plain by the north-easterly trades. Low O3

  2. A new differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington DC region

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-04-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.) from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19% from 0-1.5 km, 10-18% from 1.5-3 km, and 11-25% from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington DC area.

  3. A New Differential Absorption Lidar to Measure Sub-Hourly Fluctuation of Tropospheric Ozone Profiles in the Baltimore - Washington D.C. Region

    NASA Technical Reports Server (NTRS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-01-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99 N, 76.84 W, 57 meters ASL) from 400 m to 12 km AGL. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19 percent from 0-1.5 km, 10-18 percent from 1.5-3 km, and 11-25 percent from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore

  4. Origin and Variability of Upper Tropospheric Nitrogen Oxides and Ozone at Northern Mid-Latitudes

    NASA Technical Reports Server (NTRS)

    Grewe, V.; Brunner, D.; Dameris, M.; Grenfell, J. L.; Hein, R.; Shindell, D.; Staehelin, J.

    1999-01-01

    Measurements of NO(x) and ozone performed during the NOXAR project are compared with results from the coupled chemistry-climate models ECHAM4.L39(DLR)/CHEM and GISS-model. The measurements are based on flights between Europe and the East coast of America and between Europe and the Far East in the latitude range 40 deg N to 65 deg N. The comparison concentrates on tropopause altitudes and reveals strong longitudinal variations of seasonal mean NO,, of 200 pptv. Either model reproduced strong variations 3 km below but not at the tropopause, indicating a strong missing NO(x) or NO(y) sink over remote areas, e.g. NO(x) to HNO3 conversion by OH from additional OH sources or HNO3 wash-out. Vertical profiles show maximum NO(x) values 2-3 km below the tropopause with a strong seasonal cycle. ECHAM4.L39(DLR)/CHEM reproduces a maximum, although located at the tropopause with a less pronounced seasonal cycle, whereas the GISS model reproduces the seasonal cycle but not the profile's shape due to its coarser vertical resolution. A comparison of NO(x) frequency distributions reveals that both models are capable of reproducing the observed variability, except that ECHAM4.L39(DLR)/CHEM shows no very high NO(x) mixing ratios. Ozone mean values, vertical profiles and frequency distributions are much better reproduced in either model, indicating that the NO(x) frequency distribution, namely the most frequent NO(x) mixing ratio, is more important for the tropospheric photochemical ozone production than its mean value. Both models show that among all sources, NO(x) from lightning contributes most to the seasonal cycle of NO(x) at tropopause altitudes. The impact of lightning in the upper troposphere on NO(x) does not vary strongly with altitude, whereas the impact of surface emissions decreases with altitude. However, the models show significant differences in lightning induced NO(x) concentrations, especially in winter, which may be related to the different treatment of the lower

  5. Comprehensive study of emission source contributions for tropospheric ozone formation over East Asia

    NASA Astrophysics Data System (ADS)

    Itahashi, Syuichi; Hayami, Hiroshi; Uno, Itsushi

    2015-01-01

    Emission source contributions of tropospheric ozone (O3) were comprehensively investigated by using the higher-order decoupled direct method (HDDM) for sensitivity analysis and the ozone source apportionment technology (OSAT) for mass balance analysis in the comprehensive air-quality model with extensions (CAMx). The response of O3 to emissions reductions at various levels in mainland China, Korea, and Japan were estimated and compared with results calculated by the brute force method (BFM) where one model parameter is varied at a time. Emissions were assessed at three receptor sites in Japan that experienced severe pollution events in May 2009. For emissions from China, HDDM assessed O3 response with a bias of only up to 3 ppbv (a relative error of 4.5%) even for a 50% reduction but failed to assess a more extreme reduction. OSAT was reasonably accurate at 100% reduction, with a -4 ppbv (-7%) bias, but was less accurate at moderate ranges of reduction (˜50-70%). For emissions from Korea and Japan, HDDM captured the nonlinear response at all receptor sites and at all reduction levels to within 1% in all but one case; however, the bias of OSAT increased with the increasing reduction of emissions. One possible reason for this is that OSAT does not account for NO titration. To address this, a term for potential ozone (PO; O3 and NO2 together) was introduced. Using of PO instead of O3 improved the performance of OSAT, especially for emissions reductions from Korea and Japan. The proposed approach with PO refined the OSAT results and did not degrade HDDM performance.

  6. BVOC and tropospheric ozone fluxes from an orange orchard in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Karlik, J. F.; Goldstein, A. H.

    2010-12-01

    Citrus plants, especially oranges, are widely cultivated in the Central Valley of California and in many other countries experiencing Mediterranean climates. In many of these areas, orchards are often exposed to high levels of tropospheric ozone (O3) due to their location in polluted airsheds. Citrus take up O3 through their stomata and emit biogenic volatile organic compounds (BVOC), which can contribute to non-stomatal O3 removal through fast gas-phase reactions with O3. The study was performed in a navel orange orchard in Exeter, California. The CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously using eddy covariance techniques. Vertical concentration gradients of these compounds were also measured at 4 heights from the orchard floor to above the canopy. We observed high levels (up to 40 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 5 nmol m-2 s-1) followed by acetone. Monoterpenes fluxes were also recorded during the all vegetative period, with the highest emissions taking place during flowering periods. The orchard represented a sink for ozone, with uptake rates on the order of 10 nmol m-2 s-1 during the central hours of the day. BVOC fluxes were highly temperature dependent, while ozone fluxes were more dependent on the physiology of the orchard, consistent with dominant removal occurring through the stomatal opening. The current research is aimed at: 1. Quantifying the uptake of O3 by citrus and partitioning it into stomatal and non-stomatal processes; 2. Quantifying the BVOC emissions and their dependence on physical and ecophysiological parameters.

  7. Exploring the Production of NOx by Lightning and Its Impact on Tropospheric Ozone

    NASA Technical Reports Server (NTRS)

    Gillani, Noor; Koshak, William; Biazar, Arastoo; Doty, Kevin; Mahon, Robert; Newchurch, Michael; Byun, Daewon; Emmons, Louisa

    2006-01-01

    Our quantitative understanding of free tropospheric (FT) chemistry is quite poor. State-of-the-art regional air quality models (e.g., US EPA's CMAQ) perform very poorly in simulating FT chemistry, with Uniform ozone around 70 ppb throughout the FT in summer, while ozonesonde data show much higher levels of ozone and much spatial-temporal structure. Such models completely neglect lightning-NOx (LNOx) emissions (the most significant source of NOx in the FT), and also contain large uncertainties in the specifications of intercontinental transport, stratosphere-troposphere exchange (STE) and PBLFT exchange (PFTE). Global air chemistry models include LNOx, but in very crude fashion, with the frequency and distribution of lightning being based on modeled cloud parameters (hence large uncertainty), lightning energetics being assumed to be constant for all flashes (literature value, while in reality there is at least a two-orders of magnitude variability from flash-to-flash), and the production of NOx in the surrounding heated air, per Joule of heating, being assumed to be constant also (literature value, while in fact it is a non-linear function of the dissipated heat and local air density, p). This situation is commonly blamed on paucity of pertinent observational data, but for the USA, there is now a wealth of surface- and satellite-based data of lightning available to permit much improved observation-based estimation of LNOx emissions. In the FT, such NOx has a long residence time, and also the ozone production efficiency from NOx there is considerably higher than in the PBL. It is, therefore, of critical importance in FT chemistry. This paper will describe the approach and data products of an ongoing NSSTC project aimed at a much-improved quantification of not only LNOx production on the scale of continental USA based on local and regional lightning observations, but also of intercontinental transport, STE and PFTE, all in upgraded simulations of tropospheric

  8. Understanding patterns of variability in tropospheric ozone over Europe and eastern Asia in 2005-2009 using TES observations and the TM5 chemistry transport model

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; van Geel, M. H. A.; Boersma, K. F.

    2012-04-01

    Tropospheric ozone is an important greenhouse gas and a global air pollutant. Because of its oxidizing power, it is harmful to the tissues of many living organisms. Ozone in the troposphere is produced by photo-chemical oxidation of precursors including volatile organic compounds (VOC's) and CO in the presence of NOx. These precursors may originate from anthropogenic emissions, but may also be naturally produced by vegetation, animals, bacteria and fungi. Intrusions of stratospheric ozone into the higher troposphere also contribute to the ozone abundance in the troposphere. The interpretation of tropospheric ozone observations remains a challenging task due to complex varying spatio-temporal emissions of ozone precursors with different lifetimes (from minutes to hours, days and weeks), stratospheric intrusion, and the effect of long-range transport of precursors and ozone driven by meteorological variables. In some areas the combination of favourable photochemical regimes and specific meteorological conditions may enhance the local tropospheric ozone productions. Thanks to their extensive spatial coverage and frequent overpasses, spaceborne sensors are excellent tools to map spatio-temporal patterns of tropospheric ozone. However, evaluating trends in tropospheric ozone concentrations over Europe (e.g. Mediterranean maxima) and China requires the use of advanced chemical transport models (CTM) for understanding and attributing the different sources to the observations. The objective of this study was to evaluate time series of tropospheric ozone observed from space by TES (Tropospheric Emission Spectrometer onboard NASA's EOS-Aura satellite) with the TM5 CTM using five years (2005-2009) of observations and simulations. From dedicated TM5 model runs, the spatio-temporal TES trends of tropospheric ozone are analysed aiming at understanding the different sources and mechanisms involved. First comparison of tropospheric ozone concentration from TES v4 observations and

  9. Future Climate Impacts of Direct Radiative Forcing Anthropogenic Aerosols, Tropospheric Ozone, and Long-lived Greenhouse Gases

    NASA Technical Reports Server (NTRS)

    Chen, Wei-Ting; Liao, Hong; Seinfeld, John H.

    2007-01-01

    Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 110. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m(sup -2) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the

  10. Free troposphere ozone & carbon monoxide over the North Atlantic for 2001-2011

    NASA Astrophysics Data System (ADS)

    Kumar, Aditya

    Carbon Monoxide (CO) and Ozone (O3) are considered to be one of the most important atmospheric pollutants in the troposphere with both having significant effects on human health. Both are included in the U.S. E.P.A list of criteria pollutants. CO is primarily emitted in the source region whereas O3 can be formed near the sourc