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Earth Sciences

2003

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Chemical And Physical Properties Of Bulk Aerosols Within Four Sectors Observed During Trace-P, C. Jordan, B E. Anderson, R. Talbot, Jack E. Dibb, H Fuelberg, Charlie Hudgins, C M. Kiley, R. S. Russo, Eric Scheuer, Garry Seid, K L. Thornhill, E L. Winstead Nov 2003

Chemical And Physical Properties Of Bulk Aerosols Within Four Sectors Observed During Trace-P, C. Jordan, B E. Anderson, R. Talbot, Jack E. Dibb, H Fuelberg, Charlie Hudgins, C M. Kiley, R. S. Russo, Eric Scheuer, Garry Seid, K L. Thornhill, E L. Winstead

Earth Sciences

Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the …

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Uptake Of Nitrate And Sulfate On Dust Aerosols During Trace-P, C. Jordan, Jack E. Dibb, B E. Anderson, H Fuelberg Nov 2003

Uptake Of Nitrate And Sulfate On Dust Aerosols During Trace-P, C. Jordan, Jack E. Dibb, B E. Anderson, H Fuelberg

Earth Sciences

Aerosol data collected near Asia on the DC-8 aircraft platform during TRACE-P has been examined for evidence of uptake of NO3− and SO4= on dust surfaces. Data is compared between a sector where dust was predominant and a sector where dust was less of an influence. Coincident with dust were higher mixing ratios of anthropogenic pollutants. HNO3, SO2, and CO were higher in the dust sector than the nondust sector by factors of 2.7, 6.2, and 1.5, respectively. The colocation of dust and pollution sources allowed for the uptake of NO3 …

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Aerosol Chemical Composition In Asian Continental Outflow During The Trace-P Campaign: Comparison With Pem-West B, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Melody A. Avery, H B. Singh Nov 2003

Aerosol Chemical Composition In Asian Continental Outflow During The Trace-P Campaign: Comparison With Pem-West B, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Melody A. Avery, H B. Singh

Earth Sciences

Aerosol associated soluble ions and the radionuclide tracers 7Be and 210Pb were quantified in 414 filter samples collected in spring 2001 from the DC-8 during the Transport and Chemical Evolution over the Pacific (TRACE-P) campaign. Binning the data into near Asia (flights from Hong Kong and Japan) and remote Pacific (all other flights) revealed large enhancements of NO3−, SO4=, C2O4=, NH4+, K+, Mg2+, and Ca2+ near Asia. The boundary layer and lower troposphere were most strongly influenced by continental …

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Intercontinental Transport Of Pollution Manifested In The Variability And Seasonal Trend Of Springtime O3 At Northern Middle And High Latitudes, Yuhang Wang, Changsub Shim, Nicola J. Blake, D R. Blake, Yunsoo Choi, Brian Ridley, Jack E. Dibb, Anthony Wimmers, Jennie Moody, F Flocke, Andrew Weinheimer, R. Talbot, Elliot Atlas Nov 2003

Intercontinental Transport Of Pollution Manifested In The Variability And Seasonal Trend Of Springtime O3 At Northern Middle And High Latitudes, Yuhang Wang, Changsub Shim, Nicola J. Blake, D R. Blake, Yunsoo Choi, Brian Ridley, Jack E. Dibb, Anthony Wimmers, Jennie Moody, F Flocke, Andrew Weinheimer, R. Talbot, Elliot Atlas

Earth Sciences

Observations (0–8 km) from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment are analyzed to examine air masses contributing to the observed variability of springtime O3 and its seasonal increase at 40°–85°N over North America. Factor analysis using the positive matrix factorization and principal component analysis methods is applied to the data set with 14 chemical tracers (O3, NOy, PAN, CO, CH4, C2H2, C3H8, CH3Cl, CH3Br, C2Cl4, CFC-11, HCFC-141B, Halon-1211, and 7Be) and one …

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Chemical Composition Of Asian Continental Outflow Over The Western Pacific: Results From Transport And Chemical Evolution Over The Pacific (Trace-P), R. S. Russo, R. Talbot, Jack E. Dibb, Eric Scheuer, Garry Seid, C. Jordan, H Fuelberg, G W. Sachse, M A. Avery, S Vay, D R. Blake, N J. Blake, E L. Atlas, A Fried, S T. Sandholm, D Tan, H B. Singh, J Snow, B J. Heikes Oct 2003

Chemical Composition Of Asian Continental Outflow Over The Western Pacific: Results From Transport And Chemical Evolution Over The Pacific (Trace-P), R. S. Russo, R. Talbot, Jack E. Dibb, Eric Scheuer, Garry Seid, C. Jordan, H Fuelberg, G W. Sachse, M A. Avery, S Vay, D R. Blake, N J. Blake, E L. Atlas, A Fried, S T. Sandholm, D Tan, H B. Singh, J Snow, B J. Heikes

Earth Sciences

We characterize the chemical composition of Asian continental outflow observed during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) mission during February–April 2001 in the western Pacific using data collected on the NASA DC-8 aircraft. A significant anthropogenic impact was present in the free troposphere and as far east as 150°E longitude reflecting rapid uplift and transport of continental emissions. Five-day backward trajectories were utilized to identify five principal Asian source regions of outflow: central, coastal, north-northwest (NNW), southeast (SE), and west-southwest (WSW). The maximum mixing ratios for several species, such as CO, C2Cl4, …

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Large-Scale Ozone And Aerosol Distributions, Air Mass Characteristics, And Ozone Fluxes Over The Western Pacific Ocean In Late Winter/Early Spring, Edward V. Browell, Marta Fenn, Carolyn Butler, William B. Grant, Vincent G. Brackett, Jonathan Hair, Melody A. Avery, Yuanlong Hu, Reginald E. Newell, H Fuelberg, Daniel J. Jacob, Bruce E. Anderson, Elliot Atlas, D R. Blake, William H. Brune, Jack E. Dibb, A Fried, B J. Heikes, G W. Sachse, S T. Sandholm, Hanwant B. Singh, R. Talbot, S Vay, Rodney J. Weber, Karen B. Bartlett Oct 2003

Large-Scale Ozone And Aerosol Distributions, Air Mass Characteristics, And Ozone Fluxes Over The Western Pacific Ocean In Late Winter/Early Spring, Edward V. Browell, Marta Fenn, Carolyn Butler, William B. Grant, Vincent G. Brackett, Jonathan Hair, Melody A. Avery, Yuanlong Hu, Reginald E. Newell, H Fuelberg, Daniel J. Jacob, Bruce E. Anderson, Elliot Atlas, D R. Blake, William H. Brune, Jack E. Dibb, A Fried, B J. Heikes, G W. Sachse, S T. Sandholm, Hanwant B. Singh, R. Talbot, S Vay, Rodney J. Weber, Karen B. Bartlett

Earth Sciences

Large-scale measurements of ozone (O3) and aerosol distributions were made from the NASA DC-8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE-P) field experiment conducted in February–April 2001. Remote measurements were made with an airborne lidar to provide O3 and multiple-wavelength aerosol backscatter profiles from near the surface to above the tropopause along the flight track. In situ measurements of O3, aerosols, and a wide range of trace gases were made onboard the DC-8. Five-day backward trajectories were used in conjunction with the O3 and aerosol distributions on each flight to …

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Reactive Nitrogen In Asian Continental Outflow Over The Western Pacific: Results From The Nasa Transport And Chemical Evolution Over The Pacific (Trace-P) Airborne Mission, R. Talbot, Jack E. Dibb, Eric Scheuer, Garry Seid, R. S. Russo, S T. Sandholm, D Tan, H B. Singh, D R. Blake, N J. Blake, Elliot Atlas, G W. Sachse, C. Jordan, Melody A. Avery Oct 2003

Reactive Nitrogen In Asian Continental Outflow Over The Western Pacific: Results From The Nasa Transport And Chemical Evolution Over The Pacific (Trace-P) Airborne Mission, R. Talbot, Jack E. Dibb, Eric Scheuer, Garry Seid, R. S. Russo, S T. Sandholm, D Tan, H B. Singh, D R. Blake, N J. Blake, Elliot Atlas, G W. Sachse, C. Jordan, Melody A. Avery

Earth Sciences

We present here results for reactive nitrogen species measured aboard the NASA DC-8 aircraft during the Transport and Chemical Evolution over the Pacific (TRACE-P) mission. The large-scale distributions total reactive nitrogen (NOy,sum = NO + NO2 + HNO3 + PAN + C1–C5alkyl nitrates) and O3 and CO were better defined in the boundary layer with significant degradation of the relationships as altitude increased. Typically, NOy,sum was enhanced over background levels of ∼260 pptv by 20-to-30-fold. The ratio C2H2/CO had values of 1–4 at altitudes up to 10 …

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Summary Of Measurement Intercomparisons During Trace-P, Fred Eisele, Lee Mauldin, C A. Cantrell, M Zondlo, E C. Apel, A Fried, J Walega, R E. Shetter, Barry Lefer, F Flocke, Andrew Weinheimer, M A. Avery, S Vay, G W. Sachse, J Podolske, G S. Diskin, J D. Barrick, H B. Singh, William H. Brune, H Harder, M Martinez, A R. Bandy, D C. Thornton, B J. Heikes, Y Kondo, D Riemer, S T. Sandholm, R. Talbot, Jack E. Dibb Oct 2003

Summary Of Measurement Intercomparisons During Trace-P, Fred Eisele, Lee Mauldin, C A. Cantrell, M Zondlo, E C. Apel, A Fried, J Walega, R E. Shetter, Barry Lefer, F Flocke, Andrew Weinheimer, M A. Avery, S Vay, G W. Sachse, J Podolske, G S. Diskin, J D. Barrick, H B. Singh, William H. Brune, H Harder, M Martinez, A R. Bandy, D C. Thornton, B J. Heikes, Y Kondo, D Riemer, S T. Sandholm, R. Talbot, Jack E. Dibb

Earth Sciences

The NASA DC-8 and P-3B aircraft flew within about a kilometer or less of each other on three occasions during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign in order to intercompare similar measurements on the two aircraft. The first and last intercomparisons were in relatively remote marine environments during transits to and from Asia. The first began with a boundary layer measurement followed by an ascent to 3 km. The second set of intercomparisons was at a fixed altitude of about 5.2 km off the coast of Japan, also in relatively clean air. Finally, the third measurement …

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Greenhouse Gas Emissions From Croplands Of China, Changsheng Li, Xiangming Xiao, Steve Frolking, B Moore, William A. Salas, Jianjun Qiu, Zhang Yu, Yahui Zhuang, Xiaoke Wang, Zhaohua Dai, Jiyuan Liu, Xiaoguang Qin, Liao Bohan, Ronald Sass Sep 2003

Greenhouse Gas Emissions From Croplands Of China, Changsheng Li, Xiangming Xiao, Steve Frolking, B Moore, William A. Salas, Jianjun Qiu, Zhang Yu, Yahui Zhuang, Xiaoke Wang, Zhaohua Dai, Jiyuan Liu, Xiaoguang Qin, Liao Bohan, Ronald Sass

Earth Sciences

China possesses cropland of 1.33 million km 2. Cultivation of the cropland not only altered the biogeochemical cycles of carbon (C) and nitrogen (N) in the agroecosystems but also affected global climate. The impacts of agroecosystems on global climate attribute to emissions of three greenhouse gases, namely carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).

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Seasonal Deuterium Excess In A Tien Shan Ice Core: Influence Of Moisture Transport And Recycling In Central Asia, K Kreutz, Cameron P. Wake, V Aizen, L Dewayne Cecil, Hans-Arno Synal Sep 2003

Seasonal Deuterium Excess In A Tien Shan Ice Core: Influence Of Moisture Transport And Recycling In Central Asia, K Kreutz, Cameron P. Wake, V Aizen, L Dewayne Cecil, Hans-Arno Synal

Earth Sciences

Stable water isotope (δ18O, δD) data from a high elevation (5100 masl) ice core recovered from the Tien Shan Mountains, Kyrgyzstan, display a seasonal cycle in deuterium excess (d = δD − 8*δ18O) related to changes in the regional hydrologic cycle during 1994–2000. While there is a strong correlation (r2 = 0.98) between δ18O and δD in the ice core samples, the regression slope (6.9) and mean d value (23.0) are significantly different than the global meteoric water line values. The resulting time-series ice core d profile contains distinct winter maxima and …

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Peatland Responses To Varying Interannual Moisture Conditions As Measured By Automatic Co2 Chambers, Jill L. Bubier, P Crill, Steve Frolking, Ernst Linder, Andrew Mosedale Jun 2003

Peatland Responses To Varying Interannual Moisture Conditions As Measured By Automatic Co2 Chambers, Jill L. Bubier, P Crill, Steve Frolking, Ernst Linder, Andrew Mosedale

Earth Sciences

Net ecosystem CO2 exchange (NEE) was measured from June 2000 through October 2001 by 10 automatic chambers at a peatland in southeastern New Hampshire. The high temporal frequency of this sampling method permitted detailed examination of NEE as it varied daily and seasonally. Summer of 2001 was significantly drier than the 30-year average, while summer of 2000 was wetter than normal. Although NEE varied spatially across the peatland with differences in plant species composition and biomass, maximum CO2 uptake was 30–40% larger in the drier summer in evergreen and deciduous shrub communities but the same or lower in …

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Remotely Forced Nearshore Upwelling In Southern California, James M. Pringle, K Riser Apr 2003

Remotely Forced Nearshore Upwelling In Southern California, James M. Pringle, K Riser

Earth Sciences

[1] Alongshore winds in Baja California strongly influence nearshore temperatures hundreds of kilometers to the north at Point Loma, San Diego, California, on timescales of a week to a year. The time lag between wind and temperature is consistent with first mode coastal trapped wave phase speed. The nearshore cross-shelf circulation forced by the coastal trapped waves is, at least much of the year, oppositely directed at the surface and bottom. No relation is found between the winds and temperature for periods greater than a year. It is argued that similar results may be found elsewhere in the Southern California …

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Be-10/Be-7 Tracer Of Atmospheric Transport And Stratosphere-Troposphere Exchange, C. Jordan, Jack E. Dibb, R C. Finkel Apr 2003

Be-10/Be-7 Tracer Of Atmospheric Transport And Stratosphere-Troposphere Exchange, C. Jordan, Jack E. Dibb, R C. Finkel

Earth Sciences

The 10Be/7Be ratio is a sensitive tracer of atmospheric transport and stratosphere-troposphere exchange (STE). Data from five NASA aircraft field missions (PEM: West A and B, Tropics A; SONEX; and SUCCESS) have been assembled to produce the largest data set of 10Be,7Be, and their ratio collected to date (>300 samples). Ratios near 0.60 are indicative of tropospheric air with little stratospheric influence, while higher ratios are found in stratospheric air. Samples from the lower stratosphere were all collected within 2.5 km of the tropopause and had ratios >1.27. Of these lower stratosphere samples …

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Multiyear Modeling And Measuring Of Carbon Dioxide And Methane Exchange At A Poor Fen, Steve Frolking, P Crill, Jill L. Bubier Apr 2003

Multiyear Modeling And Measuring Of Carbon Dioxide And Methane Exchange At A Poor Fen, Steve Frolking, P Crill, Jill L. Bubier

Earth Sciences

We have made CO_2 and CH_4 flux measurements with manual chambers at Sallie`s Fen, NH, USA at weekly to monthly intervals over the past decade. We have also made quasi-continuous CO_2 flux measurements with an automated chamber flux system for the past three years. Additional ancillary data (temperature, water table depth, incoming radiation, and precipitation) have also been regularly recorded for the past decade. We also ran the PCARS peatland ecosystem model to simulate daily CO_2 and CH_4 exchange for 1997 through 2001. We compare model results to observations, and evaluate interannual variability in CO_2 and CH_4 budgets. Preliminary simulations …

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Greenhouse Gas Emission Consequences Of Large-Scale Changes In Water Management Of China’S Rice Paddies During 1980-2000, Changsheng Li, Jianjun Qiu, Steve Frolking, Xiangming Xiao, William A. Salas, B Moore, Stephen Boles, Yao Huang, Ronald Sass Apr 2003

Greenhouse Gas Emission Consequences Of Large-Scale Changes In Water Management Of China’S Rice Paddies During 1980-2000, Changsheng Li, Jianjun Qiu, Steve Frolking, Xiangming Xiao, William A. Salas, B Moore, Stephen Boles, Yao Huang, Ronald Sass

Earth Sciences

In China, midseason paddy drainage, which reduces growing season methane fluxes and enhances growing season nitrous oxide fluxes, was first implemented in the early 1980s, and has gradually replaced continuous flooding in much of the paddy rice area. We constructed a prediction rice paddy methane and nitrous oxide emissions in China using the DNDC biogeochemical model. Results of continuous flooding and midseason drainage simulations for all paddy fields in China (about 30 million ha) were combined with regional scenarios for the timing of the transition from continuous flooding to predominantly mid-season drainage to generate estimates of total methane (CH4) and …

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Modeling Soil Organic Carbon Change In Croplands Of China, Changsheng Li, Yahui Zhuang, Steve Frolking, J N. Galloway, Robert Harriss, B Moore, Alexandre C. Schimel, Xiaoke Wang Apr 2003

Modeling Soil Organic Carbon Change In Croplands Of China, Changsheng Li, Yahui Zhuang, Steve Frolking, J N. Galloway, Robert Harriss, B Moore, Alexandre C. Schimel, Xiaoke Wang

Earth Sciences

Using 1990 conditions, we modeled carbon (C) and nitrogen (N) biogeochemical cycles in croplands of China (and, for comparison, the United States) to estimate the annual soil organic-carbon (SOC) balance for all cropland. Overall, we estimate that China's croplands lost 1.6% of their SOC (to a depth of 0.3 m) in 1990, and that U.S. cropland lost 0.1%. A key element in this difference was that ∼25% of aboveground crop residue in China was returned to the soil, compared to ∼90% in the United States. In China, SOC losses were greatest in the northeast (∼103 kg C·ha–1·yr …

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Measurement And Modeling Of The Sources And Sinks Of Greenhouse Gases From Northern Wetlands, Nigel T. Roulet, Steve Frolking, P M. Lafleur, T Moore, Pierre J.H. Richard Apr 2003

Measurement And Modeling Of The Sources And Sinks Of Greenhouse Gases From Northern Wetlands, Nigel T. Roulet, Steve Frolking, P M. Lafleur, T Moore, Pierre J.H. Richard

Earth Sciences

Northern wetlands contain ≈30% of the world’s terrestrial carbon store, resulting from the incomplete decomposition of plant material inhibited because oxygen diffusion is limited by water saturation of the soil. While this behaviour results in a sink for CO2, anaerobic pathways of decomposition result in wetlands being a large, but variable, source of CH4. Northern wetlands tend to be nitrogen-impoverished, therefore they are not an important source of N2O. However, nitrogen deposition, peat extraction, and other land-use changes have the potential to alter their greenhouse gas (GHG) sink/source function. Until recently, most of the studies on the atmosphere-biosphere exchange of …

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Are There Spurious Temperature Trends In The United States Climate Division Database, Barry D. Keim, Adam M. Wilson, Cameron P. Wake, Thomas G. Huntington Apr 2003

Are There Spurious Temperature Trends In The United States Climate Division Database, Barry D. Keim, Adam M. Wilson, Cameron P. Wake, Thomas G. Huntington

Earth Sciences

The United States (U.S.) Climate Division data set is commonly used in applied climatic studies in the United States. The divisional averages are calculated by including all available stations within a division at any given time. The averages are therefore vulnerable to shifts in average station location or elevation over time, which may introduce spurious trends within these data. This paper examines temperature trends within the 15 climate divisions of New England, comparing the NCDC's U.S. Divisional Data to the U.S. Historical Climate Network (USHCN) data. Correlation and multiple regression revealed that shifts in latitude, longitude, and elevation have affected …

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Stratospheric Influence On The Northern North American Free Troposphere During Topse: 7be As A Stratospheric Tracer, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Linsey J. Debell, Barry Lefer, Brian Ridley Feb 2003

Stratospheric Influence On The Northern North American Free Troposphere During Topse: 7be As A Stratospheric Tracer, Jack E. Dibb, R. Talbot, Eric Scheuer, Garry Seid, Linsey J. Debell, Barry Lefer, Brian Ridley

Earth Sciences

We use 7Be, with HNO3 and O3, to identify air masses sampled from the NCAR C-130 during TOPSE that retained clear evidence of stratospheric influence. A total of 43 such air masses, spread fairly evenly across the February to May sampling period, and 40°N–86°N latitude range, were encountered. South of 55°N, nearly all clear stratospheric influence was restricted to altitudes above 6 km. At higher latitudes stratospherically influenced air masses were encountered as low as 2 km. Approximately 12% of all TOPSE sampling time at altitudes above 2 km was spent in stratospherically impacted air, above …

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Effect Of Sulfate Aerosol On Tropospheric Nox And Ozone Budgets: Model Simulations And Topse Evidence, Xuexi Tie, L K. Emmons, Larry Horowitz, Guy Brasseur, Brian Ridley, Elliot Atlas, Craig Stround, Peter Hess, Andrzej Klonecki, Sasha Madronich, R. Talbot, Jack E. Dibb Feb 2003

Effect Of Sulfate Aerosol On Tropospheric Nox And Ozone Budgets: Model Simulations And Topse Evidence, Xuexi Tie, L K. Emmons, Larry Horowitz, Guy Brasseur, Brian Ridley, Elliot Atlas, Craig Stround, Peter Hess, Andrzej Klonecki, Sasha Madronich, R. Talbot, Jack E. Dibb

Earth Sciences

The distributions of NOx and O3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N2O5 on sulfate aerosols has on tropospheric NOx and O3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NOx concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; …

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Tunable Diode Laser Measurements Of Formaldehyde During The Topse 2000 Study: Distributions, Trends, And Model Comparisons, A Fried, Yuhang Wang, C A. Cantrell, B Wert, J Walega, Brian Ridley, Elliot Atlas, R E. Shetter, Barry Lefer, Michael T. Coffey, James W. Hannigan, D R. Blake, N J. Blake, Simone Meinardi, R. Talbot, Jack E. Dibb, Eric Scheuer, Oliver Wingenter, J Snow, B J. Heikes, Dieter Ehhalt Feb 2003

Tunable Diode Laser Measurements Of Formaldehyde During The Topse 2000 Study: Distributions, Trends, And Model Comparisons, A Fried, Yuhang Wang, C A. Cantrell, B Wert, J Walega, Brian Ridley, Elliot Atlas, R E. Shetter, Barry Lefer, Michael T. Coffey, James W. Hannigan, D R. Blake, N J. Blake, Simone Meinardi, R. Talbot, Jack E. Dibb, Eric Scheuer, Oliver Wingenter, J Snow, B J. Heikes, Dieter Ehhalt

Earth Sciences

Airborne measurements of formaldehyde (CH2O) were acquired employing tunable diode laser absorption spectroscopy (TDLAS) during the 2000 Tropospheric Ozone Production About the Spring Equinox (TOPSE) study. This study consisted of seven deployments spanning the time period from 4 February to 23 May 2000 and covered a wide latitudinal band from 40°N to 85°N. The median measured CH2O concentrations, with a few exceptions, did not show any clear temporal trends from February to May in each of five altitude and three latitude bins examined. Detailed measurement–model comparisons were carried out using a variety of approaches employing two …

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An Estimate Of The Stratospheric Contribution To Springtime Tropospheric Ozone Maxima Using Topse Measurements And Beryllium-7 Simulations, Dale J. Allen, Jack E. Dibb, Brian Ridley, Kenneth E. Pickering, R. Talbot Feb 2003

An Estimate Of The Stratospheric Contribution To Springtime Tropospheric Ozone Maxima Using Topse Measurements And Beryllium-7 Simulations, Dale J. Allen, Jack E. Dibb, Brian Ridley, Kenneth E. Pickering, R. Talbot

Earth Sciences

Measurements of tropospheric ozone (O3) between 30°N and 70°N show springtime maxima at remote locations. The contribution of seasonal changes in stratosphere–troposphere exchange (STE) to these maxima was investigated using measurements from the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) campaign and the beryllium-7 (7Be) distribution from a calculation driven by fields from the Goddard Earth Observing System Data Assimilation System (GEOS DAS). Comparison with TOPSE measurements revealed that upper tropospheric model-calculated 7Be mixing ratios were reasonable (a change from previous calculations) but that lower tropospheric mixing ratios were too low most likely …

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Coupled Evolution Of Brox-Clox-Hox-Nox Chemistry During Bromine-Catalyzed Ozone Depletion Events In The Arctic Boundary Layer, M J. Evans, D J. Jacob, E L. Atlas, C A. Cantrell, Fred Eisele, F Flocke, A Fried, R L. Mauldin, Brian Ridley, B Wert, R. Talbot, D R. Blake, B J. Heikes, J Snow, J Walega, Andrew Weinheimer, Jack E. Dibb Feb 2003

Coupled Evolution Of Brox-Clox-Hox-Nox Chemistry During Bromine-Catalyzed Ozone Depletion Events In The Arctic Boundary Layer, M J. Evans, D J. Jacob, E L. Atlas, C A. Cantrell, Fred Eisele, F Flocke, A Fried, R L. Mauldin, Brian Ridley, B Wert, R. Talbot, D R. Blake, B J. Heikes, J Snow, J Walega, Andrew Weinheimer, Jack E. Dibb

Earth Sciences

Extensive chemical characterization of ozone (O3) depletion events in the Arctic boundary layer during the TOPSE aircraft mission in March–May 2000 enables analysis of the coupled chemical evolution of bromine (BrOx), chlorine (ClOx), hydrogen oxide (HOx) and nitrogen oxide (NOx) radicals during these events. We project the TOPSE observations onto an O3 chemical coordinate to construct a chronology of radical chemistry during O3 depletion events, and we compare this chronology to results from a photochemical model simulation. Comparison of observed trends in ethyne (oxidized by Br) and ethane …

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Investigations Into Free Tropospheric New Particle Formation In The Central Canadian Arctic During The Winter/Spring Transition As Part Of Topse, R J. Weber, D A. Orsini, B Wang, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, R L. Mauldin, E Kosciuch, C A. Cantrell, Fred Eisele Feb 2003

Investigations Into Free Tropospheric New Particle Formation In The Central Canadian Arctic During The Winter/Spring Transition As Part Of Topse, R J. Weber, D A. Orsini, B Wang, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, R L. Mauldin, E Kosciuch, C A. Cantrell, Fred Eisele

Earth Sciences

In this paper, we investigate the role of in situ new particle production in the central Canadian sub-Arctic and Arctic as part of the TOPSE experiment. Airborne measurements conducted primarily in the free troposphere were made from 50° to 90°W longitude and 60° to 85°N latitude during the period from February to May 2000. Data pertinent to this paper include 3–4 nm diameter (Dp) particles, ultrafine condensation nuclei (Dp > 3 nm), fine particles (0.2 < Dp < 3 μm), and the possible nucleation precursor, sulfuric acid, and its precursor, sulfur dioxide. For data averaged over this period, most species showed little evidence for a latitudinal trend. Fine aerosol number concentrations, however, showed a slight increase with latitude. The evolution of various species concentrations over the period of the study show that fine particles also had a consistent temporal trend, increasing at all altitudes from February to May, whereas sulfur dioxide at the surface tended to peak in late March. Ultrafine condensation nuclei and 3–4 nm particles showed no temporal trends. Little evidence for in situ new particle production was observed during the study, except for one atypical event where SO2concentrations were 3.5 ppbv, 2 orders of magnitude higher than typical levels. This paper cannot address the question of whether the observed condensation nuclei were …

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Ozone Depletion Events Observed In The High Latitude Surface Layer During The Topse Aircraft Program, Brian Ridley, Elliot Atlas, D Montzka, Edward V. Browell, C A. Cantrell, D R. Blake, N J. Blake, L Cinquini, Michael T. Coffey, L K. Emmons, Ronald C. Cohen, Russell J. Deyoung, Jack E. Dibb, Fred Eisele, F Flocke, A Fried, F E. Grahek, William B. Grant, Jonathan Hair, James W. Hannigan, B J. Heikes, Barry Lefer, R L. Mauldin, Jennie Moody, R E. Shetter, J Snow, R. Talbot, J A. Thornton, J Walega, Andrew Weinheimer, B Wert, Anthony Wimmers Feb 2003

Ozone Depletion Events Observed In The High Latitude Surface Layer During The Topse Aircraft Program, Brian Ridley, Elliot Atlas, D Montzka, Edward V. Browell, C A. Cantrell, D R. Blake, N J. Blake, L Cinquini, Michael T. Coffey, L K. Emmons, Ronald C. Cohen, Russell J. Deyoung, Jack E. Dibb, Fred Eisele, F Flocke, A Fried, F E. Grahek, William B. Grant, Jonathan Hair, James W. Hannigan, B J. Heikes, Barry Lefer, R L. Mauldin, Jennie Moody, R E. Shetter, J Snow, R. Talbot, J A. Thornton, J Walega, Andrew Weinheimer, B Wert, Anthony Wimmers

Earth Sciences

During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58° between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as …

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Seasonal Distributions Of Fine Aerosol Sulfate In The North American Arctic Basin During Topse, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, Barry Lefer Feb 2003

Seasonal Distributions Of Fine Aerosol Sulfate In The North American Arctic Basin During Topse, Eric Scheuer, R. Talbot, Jack E. Dibb, Garry Seid, Linsey J. Debell, Barry Lefer

Earth Sciences

We used the mist chamber/ion chromatography technique to quantify fine aerosol SO4=(<2.7 μm) in the Arctic during the Tropospheric Ozone Production about the Spring Equinox Experiment (TOPSE) with about 2.5 min time resolution. Our effective sample area ranged from 50° to 86°N and 53° to 100°W. The seasonal evolution of fine aerosol sulfate in the Arctic troposphere during TOPSE was consistent with the phenomenon of Arctic haze. Arctic haze has been attributed to pollution from sources in the Arctic and pollution transported meridionally along stable isentropes into the Arctic in geographically broad but vertically narrow bands. These layers became more prevalent at higher altitudes as the season progressed toward summer, and the relevant isentropes are not held so close to the surface. Mean fine particle SO4= mixing ratios during TOPSE in February below 1000 m were elevated (112 pptv) and highly variable (between 28 and 290 pptv) but were significantly lower at higher altitudes (about 40 pptv). As the season progressed, elevated mixing ratios and higher variability were observed at higher altitudes, up to 7 km. In May, mixing ratios at the lowest altitudes declined but still remained higher than in February at all altitudes. The high variability in our measurements likely reflects the vertical heterogeneity of the wintertime …

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Steady State Free Radical Budgets And Ozone Photochemistry During Topse, C A. Cantrell, Lee Mauldin, M Zondlo, Fred Eisele, E Kosciuch, R E. Shetter, Barry Lefer, S R. Hall, T L. Campos, Brian Ridley, J Walega, A Fried, B Wert, F Flocke, Andrew Weinheimer, James W. Hannigan, Michael T. Coffey, Elliot Atlas, S Stephens, B J. Heikes, J Snow, D R. Blake, N J. Blake, A Katzenstein, J Lopez, Edward V. Browell, Jack E. Dibb, Eric Scheuer, Garry Seid, R. Talbot Feb 2003

Steady State Free Radical Budgets And Ozone Photochemistry During Topse, C A. Cantrell, Lee Mauldin, M Zondlo, Fred Eisele, E Kosciuch, R E. Shetter, Barry Lefer, S R. Hall, T L. Campos, Brian Ridley, J Walega, A Fried, B Wert, F Flocke, Andrew Weinheimer, James W. Hannigan, Michael T. Coffey, Elliot Atlas, S Stephens, B J. Heikes, J Snow, D R. Blake, N J. Blake, A Katzenstein, J Lopez, Edward V. Browell, Jack E. Dibb, Eric Scheuer, Garry Seid, R. Talbot

Earth Sciences

A steady state model, constrained by a number of measured quantities, was used to derive peroxy radical levels for the conditions of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) campaign. The analysis is made using data collected aboard the NCAR/NSF C-130 aircraft from February through May 2000 at latitudes from 40° to 85°N, and at altitudes from the surface to 7.6 km. HO2 + RO2 radical concentrations were measured during the experiment, which are compared with model results over the domain of the study showing good agreement on the average. Average measurement/model ratios are 1.04 (σ …

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Springtime Photochemistry At Northern Mid And High Latitudes, Yuhang Wang, Brian Ridley, A Fried, C A. Cantrell, D D. Davis, Gao Chen, J Snow, B J. Heikes, R. Talbot, Jack E. Dibb, F Flocke, Andrew Weinheimer, N J. Blake, D R. Blake, R E. Shetter, Barry Lefer, Elliot Atlas, Michael T. Coffey, J Walega, B Wert Feb 2003

Springtime Photochemistry At Northern Mid And High Latitudes, Yuhang Wang, Brian Ridley, A Fried, C A. Cantrell, D D. Davis, Gao Chen, J Snow, B J. Heikes, R. Talbot, Jack E. Dibb, F Flocke, Andrew Weinheimer, N J. Blake, D R. Blake, R E. Shetter, Barry Lefer, Elliot Atlas, Michael T. Coffey, J Walega, B Wert

Earth Sciences

Physical and chemical properties of the atmosphere at 0–8 km were measured during the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiments from February to May 2000 at mid (40°–60°N) and high latitudes (60°–80°N). The observations were analyzed using a diel steady state box model to examine HOx and O3 photochemistry during the spring transition period. The radical chemistry is driven primarily by photolysis of O3 and the subsequent reaction of O(1D) and H2O, the rate of which increases rapidly during spring. Unlike in other tropospheric experiments, observed H2O2 …

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A 100-Year Record Of North Pacific Volcanism In An Ice Core From Eclipse Icefield, Yukon Territory, Canada, Kaplan Yalcin, Cameron P. Wake, Mark S. Germani Jan 2003

A 100-Year Record Of North Pacific Volcanism In An Ice Core From Eclipse Icefield, Yukon Territory, Canada, Kaplan Yalcin, Cameron P. Wake, Mark S. Germani

Earth Sciences

A record of regionally significant volcanic eruptions in the North Pacific over the last century has been developed using a glaciochemical record from Eclipse Icefield, Yukon Territory, Canada. Tephrochronology of the Eclipse ice core provides positive identification of the 1907 Ksudach, Kamchatka, the 1912 Katmai, Alaska, the 1947 Hekla, Iceland, and the 1989 Redoubt, Alaska, eruptions. Non-sea-salt SO42− residuals above a robust spline and empirical orthogonal function (EOF) analysis were used to identify volcanic SO42− signatures. Volcanic sulfate values are more conservatively identified by the EOF analysis as sulfate deposition from other sources is more robustly …

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Ozone, Aerosol, Potential Vorticity, And Trace Gas Trends Observed At High-Latitudes Over North America From February To May 2000, Edward V. Browell, Jonathan Hair, Carolyn Butler, William B. Grant, Russell J. Deyoung, Marta Fenn, Vincent G. Brackett, Marian B. Clayton, Lorraine A. Brasseur, David B. Harper, Brian Ridley, Andrzej Klonecki, Peter Hess, L K. Emmons, Xuexi Tie, Elliot Atlas, C A. Cantrell, Anthony Wimmers, D R. Blake, Michael T. Coffey, James W. Hannigan, Jack E. Dibb, R. Talbot, F Flocke, Andrew Weinheimer, A Fried, B Wert, J Snow, Barry Lefer Jan 2003

Ozone, Aerosol, Potential Vorticity, And Trace Gas Trends Observed At High-Latitudes Over North America From February To May 2000, Edward V. Browell, Jonathan Hair, Carolyn Butler, William B. Grant, Russell J. Deyoung, Marta Fenn, Vincent G. Brackett, Marian B. Clayton, Lorraine A. Brasseur, David B. Harper, Brian Ridley, Andrzej Klonecki, Peter Hess, L K. Emmons, Xuexi Tie, Elliot Atlas, C A. Cantrell, Anthony Wimmers, D R. Blake, Michael T. Coffey, James W. Hannigan, Jack E. Dibb, R. Talbot, F Flocke, Andrew Weinheimer, A Fried, B Wert, J Snow, Barry Lefer

Earth Sciences

Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight flights over seven deployments covering the latitudes of 40°–85°N between 4 February and 23 May 2000 as part of the Tropospheric Ozone Production about the Spring Equinox (TOPSE) field experiment. Each deployment started from Broomfield, Colorado, with bases in Churchill, Canada, and on most deployments, Thule Air Base, Greenland. Nadir and zenith lidar O3 measurements were combined with in situ O3measurements to produce vertically continuous O3 profiles from near the surface to above the tropopause. Potential vorticity (PV) distributions …

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