Physical Sciences and Mathematics | Open Access Articles

Snow Accumulation, Surface Height Change, And Firn Densification At Summit, Greenland: Insights From 2 Years Of In Situ Observation, Jack E. Dibb, Mark Fahnestock

Earth Sciences

Weekly measurements of surface height change were made at an accumulation forest of 100 stakes at Summit, Greenland, over a 2-year period (17 August 2000 to 8 August 2002). On average, the surface height relative to the stakes increased 64 (±4.8) cm in the first year and 65 (±5.3) cm in the second, identical to the average (65 ± 4.5 cm yr⁻¹) previously reported for the period 1991–1995 in a similar forest 28 km to the southwest. The continuous 2-year data set indicates that the rate of surface rise was not constant, with the summers of 2001 and …

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Summertime Ozone At Mount Washington: Meteorological Controls At The Highest Peak In The Northeast, E V. Fischer, R. Talbot, Jack E. Dibb

Earth Sciences

This study examined the synoptic and regional-scale meteorological controls on summertime O₃ at Mount Washington, the highest peak (1910 m) in the northeastern United States. Analysis of air mass transport to Mount Washington was conducted for the summers of 1998–2003 using backward trajectories. Distinct patterns in air mass history were revealed using this approach that helped explain extreme variations in O₃ mixing ratios. Most enhanced (≥90th percentile) and depleted (≤10th percentile) O₃ events were short-lived and spread out over the summer months. Enhanced O₃ events at Mount Washington were generally associated with westerly transport, while depleted …

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Ship-Based Nitric Acid Measurements In The Gulf Of Maine During New England Air Quality Study 2002, Jack E. Dibb, Eric Scheuer, Sallie I. Whitlow, Marcy Vozzella, Eric Williams, Brian M. Lerner

Earth Sciences

Gas phase nitric acid (HNO₃) was measured at 5-min resolution on board the National Oceanographic and Atmospheric Administration (NOAA) research vessel Ronald H. Brown during the second leg (29 July to 10 August) of the New England Air Quality Study (NEAQS) 2002 cruise. A primary objective of the cruise was to improve understanding of the oxidation of NO_x in, and removal of the oxidation products from, the polluted marine boundary layer east of northeastern North America. For the first 9 days of this leg the ship remained north of Cape Cod, and the cruise track did not …

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Three-Dimensional Simulations Of Inorganic Aerosol Distributions In East Asia During Spring 2001, Youhua Tang, Gregory R. Carmichael, John H. Seinfeld, Donald Dabdub, Rodney J. Weber, B J. Huebert, A D. Clarke, Sergio A. Guazzotti, David A. Sodeman, Kimberly A. Prather, Itsushi Uno, Jung -Hun Woo, James J. Yienger, David G. Streets, Patricia K. Quinn, James E. Johnson, Chul-Han Song, Vicki H. Grassian, Adrian Sandu, R. Talbot, Jack E. Dibb

Earth Sciences

In this paper, aerosol composition and size distributions in east Asia are simulated using a comprehensive chemical transport model. Three-dimensional aerosol simulations for the TRACE-P and ACE-Asia periods are performed and used to help interpret actual observations. The regional chemical transport model, STEM-2K3, which includes the on-line gas-aerosol thermodynamic module SCAPE II, and explicitly considers chemical aging of dust, is used in the analysis. The model is found to represent many of the important observed features. The Asian outflow during March and April of 2001 is heavily polluted with high aerosol loadings. Under conditions of low dust loading, SO_{2 …}

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A Major Regional Air Pollution Event In The Northeastern United States Caused By Extensive Forest Fires In Quebec, Canada, Linsey J. Debell, Jack E. Dibb, R. Talbot, J W. Munger, E V. Fischer, Steve Frolking

Earth Sciences

During early July 2002, wildfires burned ∼1 × 10⁶ ha of forest in Quebec, Canada. The resultant smoke plume was seen in satellite images blanketing the U.S. east coast. Concurrently, extremely high CO mixing ratios were observed at the Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) network sites in New Hampshire and at the Harvard Forest Environmental Measurement Site (HFEMS) in Massachusetts. The CO enhancements were on the order of 525–1025 ppbv above low mixing ratio conditions on surrounding days. A biomass burning source for the event was confirmed by concomitant enhancements in aerosol K⁺, NH …

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Intercomparisons Of Airborne Measurements Of Aerosol Ionic Chemical Composition During Trace-P And Ace-Asia, Y Ma, R J. Weber, K Maxwell-Meier, D A. Orsini, Y-N Lee, B J. Huebert, S G. Howell, T H. Bertram, R. Talbot, Jack E. Dibb, Eric Scheuer

Earth Sciences

As part of the two field studies, Transport and Chemical Evolution over the Pacific (TRACE-P) and the Asian Aerosol Characterization Experiment (ACE-Asia), the inorganic chemical composition of tropospheric aerosols was measured over the western Pacific from three separate aircraft using various methods. Comparisons are made between the rapid online techniques of the particle into liquid sampler (PILS) for measurement of a suite of fine particle a mist chamber/ion chromatograph (MC/IC) measurement of fine sulfate, and the longer time-integrated filter and micro-orifice impactor (MOI) measurements. Comparisons between identical PILS on two separate aircraft flying in formation showed that they were highly …

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A Comparison Of Similar Aerosol Measurements Made On The Nasa P3-B, Dc-8, And Nsf C-130 Aircraft During Trace-P And Ace-Asia, K G. Moore, A D. Clarke, V Kapustin, Cameron Mcnaughton, B E. Anderson, E L. Winstead, R J. Weber, Y Ma, Y N. Lee, R. Talbot, Jack E. Dibb, T Anderson, S Dougherty, D Covert, D Rogers

Earth Sciences

Two major aircraft experiments occurred off the Pacific coast of Asia during spring 2001: the NASA sponsored Transport and Chemical Evolution over the Pacific (TRACE-P) and the National Science Foundation (NSF) sponsored Aerosol Characterization Experiment-Asia (ACE-Asia). Both experiments studied emissions from the Asian continent (biomass burning, urban/industrial pollution, and dust). TRACE-P focused on trace gases and aerosol during March/April and was based primarily in Hong Kong and Yokota Air Force Base, Japan, and involved two aircraft: the NASA DC-8 and the NASA P3-B. ACE-Asia focused on aerosol and radiation during April/May and was based in Iwakuni Marine Corps Air Station, …

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Carbonyl Sulfide And Carbon Disulfide: Large-Scale Distributions Over The Western Pacific And Emissions From Asia During Trace-P, Nicola J. Blake, David G. Streets, Jung -Hun Woo, Isobel J. Simpson, Jonathan Green, Simone Meinardi, Kazuyuki Kita, E L. Atlas, H Fuelberg, Glen Sachse, Melody A. Avery, S Vay, R. Talbot, Jack E. Dibb, A R. Bandy, D C. Thornton, F Sherwood Rowland, D R. Blake

Earth Sciences

An extensive set of carbonyl sulfide (OCS) and carbon disulfide (CS₂) observations were made as part of the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) project, which took place in the early spring 2001. TRACE-P sampling focused on the western Pacific region but in total included the geographic region 110°E to 290°E longitude, 5°N to 50°N latitude, and 0–12 km altitude. Substantial OCS and CS₂ enhancements were observed for a great many air masses of Chinese and Japanese origin during TRACE-P. Over the western Pacific, mean mixing ratios of long-lived OCS and shorter-lived CS_{2 …}

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Constraints On The Sources Of Tropospheric Ozone From 210pb-7be-O3 Correlations, Hongyu Liu, Daniel Jacob, Jack E. Dibb, Arlene M. Fiore, Robert Yantosca

Earth Sciences

The 210Pb-7 Be-O3 relationships observed in three aircraft missions over the western Pacific (PEM-West A and B, TRACE-P) are simulated with a global three-dimensional chemical tracer model (GEOS-CHEM) driven by assimilated meteorological observations. Results are interpreted in terms of the constraints that they offer on sources of tropospheric ozone (O3). Aircraft observations of fresh Asian outflow show strong 210Pb-O3 correlations in September–October, but such correlations are only seen at low latitudes in February–March. Observations further downwind over the Pacific show stronger 210PbO3 correlations in February–March than in September–October. The model reproduces these results and attributes the seasonal contrast to strong …

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Nighttime Removal Of Nox In The Summer Marine Boundary Layer, S S. Brown, Jack E. Dibb, H Stark, M Aldener, Marcy Vozzella, Sallie I. Whitlow, E J. Williams, Brian M. Lerner, R Jakoubek, A M. Middlebrook, J A. Degouw, C Warneke, P D. Goldan, W C. Kuster, W M. Angevine, D Sueper, Patricia K. Quinn, Timothy S. Bates, James Meagher, Fred C. Fehsenfeld, A R. Ravishankara

Earth Sciences

The nitrate radical, NO3, and dinitrogen pentoxide, N2O5, are two important components of nitrogen oxides that occur predominantly at night in the lower troposphere. Because a large fraction of NO2 reacts to form NO3 and N2O5 during the course of a night, their fate is an important determining factor to the overall fate of NOx (=NO and NO2). As a comprehensive test of nocturnal nitrogen oxide chemistry, concentrations of O3, NO, NO2, NO3, N2O5, HNO3 and a host of other relevant compounds, aerosol abundance and composition, and meteorological conditions were measured in the marine boundary layer from the NOAA research …

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Relationships Between Surface And Column Aerosol Radiative Properties And Air Mass Transport At A Rural New England Site, J F. Slater, Jack E. Dibb

Earth Sciences

Chemical, physical, and radiative properties of surface and vertical column aerosols were measured at a rural site in southern New Hampshire from July 2000 to September 2001. The primary objective was to determine how intensive and extensive aerosol properties vary in air masses originating in different upwind regions. The data set also allows for an investigation of some of the relationships between surface and column aerosol properties at the site, and provides an estimate of direct radiative forcing by aerosols during the study period. Extensive properties (e.g., optical depth and chemical concentration) were at maximum values during times of south-southwest …

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Asian Dust Storm Events Of Spring 2001 And Associated Pollutants Observed In New England By The Atmospheric Investigation, Regional Modeling, Analysis And Prediction (Airmap) Monitoring Network, Linsey J. Debell, Marcy Vozzella, R. Talbot, Jack E. Dibb

Earth Sciences

Between 18 April and 13 May 2001, three statistically extreme dust aerosol events were observed across the entire northeastern United States. High levels of bulk aerosol water-soluble Ca²⁺ (range = 42–482 pptv) and PM_2.5 elemental Ca (range = 19–156 pptv) were observed simultaneously at Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) and Interagency Monitoring of Protected Visual Environments (IMPROVE) stations. On the basis of Ca²⁺ concentrations, the average bulk dust concentration for all events across all four AIRMAP stations was estimated to be 7.4 μg/m³. There was no evidence of dust outbreaks in North …

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Full-Text Articles in Physical Sciences and Mathematics

Snow Accumulation, Surface Height Change, And Firn Densification At Summit, Greenland: Insights From 2 Years Of In Situ Observation, Jack E. Dibb, Mark Fahnestock

Earth Sciences

Summertime Ozone At Mount Washington: Meteorological Controls At The Highest Peak In The Northeast, E V. Fischer, R. Talbot, Jack E. Dibb

Earth Sciences

Ship-Based Nitric Acid Measurements In The Gulf Of Maine During New England Air Quality Study 2002, Jack E. Dibb, Eric Scheuer, Sallie I. Whitlow, Marcy Vozzella, Eric Williams, Brian M. Lerner

Earth Sciences

Earth Sciences

A Major Regional Air Pollution Event In The Northeastern United States Caused By Extensive Forest Fires In Quebec, Canada, Linsey J. Debell, Jack E. Dibb, R. Talbot, J W. Munger, E V. Fischer, Steve Frolking

Earth Sciences

Intercomparisons Of Airborne Measurements Of Aerosol Ionic Chemical Composition During Trace-P And Ace-Asia, Y Ma, R J. Weber, K Maxwell-Meier, D A. Orsini, Y-N Lee, B J. Huebert, S G. Howell, T H. Bertram, R. Talbot, Jack E. Dibb, Eric Scheuer

Earth Sciences

Earth Sciences

Earth Sciences

Constraints On The Sources Of Tropospheric Ozone From 210pb-7be-O3 Correlations, Hongyu Liu, Daniel Jacob, Jack E. Dibb, Arlene M. Fiore, Robert Yantosca

Earth Sciences

Earth Sciences

Relationships Between Surface And Column Aerosol Radiative Properties And Air Mass Transport At A Rural New England Site, J F. Slater, Jack E. Dibb

Earth Sciences

Asian Dust Storm Events Of Spring 2001 And Associated Pollutants Observed In New England By The Atmospheric Investigation, Regional Modeling, Analysis And Prediction (Airmap) Monitoring Network, Linsey J. Debell, Marcy Vozzella, R. Talbot, Jack E. Dibb

Earth Sciences