Now showing items 1-20 of 33

• #### Air-snow exchange of HNO3 and NOy at Summit, Greenland ﻿

(Wiley-Blackwell, 1998)
Ice core records of NO3− deposition to polar glaciers could provide unrivaled information on past photochemical status and N cycling dynamics of the troposphere, if the ice core records could be inverted to yield concentrations ...
• #### Black carbon and its correlation with trace gases at a rural site in Beijing: Top-down constraints from ambient measurements on bottom-up emissions ﻿

(Wiley-Blackwell, 2011)
The mass concentrations of black carbon (BC) were measured continuously at Miyun, a rural site near Beijing, concurrently with some trace gases (CO, CO2, NOy, SO2) during the nonheating seasons of 2010 (April to October). ...
• #### Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks ﻿

(Proceedings of the National Academy of Sciences, 2008)
The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth's climate system has been considered. Despite this, ...
• #### Carboxylic acids in clouds at a high-elevation forested site in central Virginia ﻿

(Wiley-Blackwell, 1995)
During September 1990 we sampled coarse (>18-μm diameter) and fine (18- to 5.5-μm diameter) droplets and liquid-water content (LWC) in cloud from a tower on a forested ridge top in Shenandoah National Park, Virginia. ...
• #### Carboxylic acids in the rural continental atmosphere over the eastern United States during the Shenandoah Cloud and Photochemistry Experiment ﻿

(Wiley-Blackwell, 1995)
The Shenandoah Cloud and Photochemistry Experiment (SCAPE) was conducted during September 1990 in the rural continental atmosphere at a mountain top site (1014 m) in Shenandoah National Park, Virginia. We report here the ...
• #### Comparison of net ecosystem carbon exchange estimation in a mixed temperate forest using field eddy covariance and MODIS data ﻿

(Springer International Publishing, 2016)
Quantification of net ecosystem carbon exchange (NEE) between the atmosphere and vegetation is of great importance for regional and global studies of carbon balance. The eddy covariance technique can quantify carbon budgets ...
• #### Concentrations and snow-atmosphere fluxes of reactive nitrogen at Summit, Greenland ﻿

(Wiley-Blackwell, 1999)
Concentrations and fluxes of NOy (total reactive nitrogen), ozone concentrations and fluxes of sensible heat, water vapor, and momentum were measured from May 1 to July 20, 1995 at Summit, Greenland. Median NOy concentrations ...
• #### A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data ﻿

(Elsevier BV, 2010)
The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements ...
• #### An ecosystem-scale perspective of the net land methanol flux: synthesis of micrometeorological flux measurements ﻿

(2015)
Methanol is the second most abundant volatile organic compound in the troposphere and plays a significant role in atmospheric chemistry. While there is consensus about the dominant role of living plants as the major source ...
• #### Export of NOy from the North American boundary layer: Reconciling aircraft observations and global model budgets ﻿

(Wiley-Blackwell, 2004)
Fossil fuel combustion accounts for >50% of the global atmospheric emission of NOx, but this source is concentrated in the polluted continental boundary layer (CBL) and only a small fraction is exported as NOy (NOx and its ...
• #### Formaldehyde, glyoxal, and methylglyoxal in air and cloudwater at a rural mountain site in central Virginia ﻿

(Wiley-Blackwell, 1995)
As part of the Shenandoah Cloud and Photochemistry Experiment (SCAPE), we measured formaldehyde (HCHO), glyoxal (CHOCHO), and methylglyoxal (CH3C(O)CHO) concentrations in air and cloudwater at Pinnacles (elevation 1037 m) ...
• #### The H 2 SO 4 -HNO 3 -NH 3 system at high humidities and in fogs: 1. Spatial and temporal patterns in the San Joaquin Valley of California ﻿

(Wiley-Blackwell, 1986)
A systematic characterization of the atmospheric H2SO4-HNO3-NH3 system was conducted in the fog water, the aerosol, and the gas phase at a network of sites in the San Joaquin Valley of California. Spatial patterns of ...
• #### The $H_2SO_4-HNO_3-NH_3$ system at high humidities and in fogs: 2. Comparison of field data with thermodynamic calculations ﻿

(Wiley-Blackwell, 1986)
Concentrations of HNO(g) and NH(g) determined in the field were compared to predictions from aerosol equilibrium models. The products of HNO(g) and NH(g) concentrations measured under cool and humid nonfoggy conditions ...
• #### Harvard Forest regional-scale air mass composition by Patterns in Atmospheric Transport History (PATH) ﻿

(Wiley-Blackwell, 1998)
We calculated 4 years (1990–1993) of back trajectories arriving at Harvard Forest and used them to define patterns in atmospheric transport history. This information was used to assess the degree to which regional-scale ...
• #### Increasing background ozone in surface air over the United States ﻿

(Wiley-Blackwell, 2000)
The long-term trend of background O3 in surface air over the United States from 1980 to 1998 is examined using monthly probability distributions of daily maximum 8-hour average O3 concentrations at a large ensemble of rural ...
• #### Nitrogen Deposition to the United States: Distribution, Sources, and Processes ﻿

(European Geosciences Union, 2012)
We simulate nitrogen deposition over the US in 2006–2008 by using the GEOS-Chem global chemical transport model at 1/2°×2/3° horizontal resolution over North America and adjacent oceans. US emissions of NOx and NH3 in the ...
• #### Ozone Air Quality During the 2008 Beijing Olympics: Effectiveness of Emission Restrictions ﻿

(Copernicus Publications, 2009)
A series of aggressive measures was launched by the Chinese government to reduce pollutant emissions from Beijing and surrounding areas during the Olympic Games. Observations at Miyun, a rural site 100 km downwind of the ...
• #### Reactive nitrogen oxides and ozone above a taiga woodland ﻿

(Wiley-Blackwell, 1994)
Measurements of reactive nitrogen oxides (NOₓ and NO{sub y}) and ozone (O₃) were made in the planetary boundary layer (PBL) above a taiga woodland in northern Quebec, Canada, during June-August, 1990, as part of NASA Arctic ...
• #### Relationship of ozone and carbon monoxide over North America ﻿

(Wiley-Blackwell, 1994)
Observations at sites in eastern North America show a strong correlation between O3 and CO concentrations in summer, with a consistent slope ΔO3/ΔCO ≈ 0.3. Observations in the aged Denver plume at Niwot Ridge, Colorado, ...
• #### Responses of terrestrial ecosystems and carbon budgets to current and future environmental variability ﻿

(Proceedings of the National Academy of Sciences, 2010)
We assess the significance of high-frequency variability of environmental parameters (sunlight, precipitation, temperature) for the structure and function of terrestrial ecosystems under current and future climate. We ...