Now showing items 21-40 of 56

• #### Factors regulating ozone over the United States and its export to the global atmosphere ﻿

(Wiley-Blackwell, 1993)
The factors regulating summertime O over the United States and its export to the global atmosphere are examined with a 3‐month simulation using a continental scale, three‐dimensional photochemical model. It is found that ...
• #### Fluxes of Atmospheric Methane Using Novel Instruments, Field Measurements, and Inverse Modeling ﻿

(2013-09-24)
The atmospheric concentration of methane $(CH_4)$ - the most significant non-$CO_2$ anthropogenic long-lived greenhouse gas - stabilized between 1999 and 2006 and then began to rise again. Explanations for this behavior ...
• #### Global-scale black carbon profiles observed in the remote atmosphere and compared to models ﻿

(Wiley-Blackwell, 2010)
[1] Refractory black carbon (rBC) aerosol loadings and mass size distributions have been quantified during the HIPPO campaign above the remote Pacific from 80N to 67S. Over 100 vertical profiles of rBC loadings, extending ...
• #### 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 ...
• #### HIAPER Pole-to-Pole Observations (HIPPO): fine-grained, global-scale measurements of climatically important atmospheric gases and aerosols ﻿

(The Royal Society, 2011)
The HIAPER Pole-to-Pole Observations (HIPPO) programme has completed three of five planned aircraft transects spanning the Pacific from 85° N to 67° S, with vertical profiles every approximately 2.2° of latitude. Measurements ...
• #### High sensitivity of peat decomposition to climate change through water-table feedback ﻿

(Nature Publishing Group, 2008)
Historically, northern peatlands have functioned as a carbon sink, sequestering large amounts of soil organic carbon, mainly due to low decomposition in cold, largely waterlogged soils. The water table, an essential ...
• #### High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) using the cavity ring-down spectroscopy (CRDS) technique ﻿

(Copernicus GmbH, 2010)
High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available ...
• #### Least independent variables method for simulation of tropospheric ozone ﻿

(Wiley-Blackwell, 1989)
We describe a method for simulating photochemical production of O in a continental‐scale tropospheric model with only six independent chemical variables representing tracers transported in the model. The tracers are two ...
• #### Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts ﻿

(Proceedings of the National Academy of Sciences, 2015)
Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas ...
• #### Methane Leaks from North American Natural Gas Systems ﻿

(American Association for the Advancement of Science (AAAS), 2014)
Natural gas (NG) is a potential “bridge fuel” during transition to a decarbonized energy system: It emits less carbon dioxide during combustion than other fossil fuels and can be used in many industries. However, because ...
• #### Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra ﻿

(Wiley-Blackwell, 1992)
Exchanges of methane and carbon dioxide between the atmosphere and the Arctic tundra were measured continuously near Bethel, Alaska (61°05.41'N 162°00.92'W), for 5 weeks during July and August 1988. Fluxes were obtained ...
• #### Modeling Analysis of Primary Controls on Net Ecosystem Productivity of Seven Boreal and Temperate Coniferous Forests Across a Continental Transect ﻿

(Blackwell Publishing, 2008)
Process-based models are effective tools to synthesize and/or extrapolate measured carbon (C) exchanges from individual sites to large scales. In this study, we used a C- and nitrogen (N)-cycle coupled ecosystem model named ...
• #### A Multi-Site Analysis of Random Error in Tower-Based Measurements of Carbon and Energy Fluxes ﻿

(Elsevier, 2006)
Measured surface-atmosphere ﬂuxes of energy (sensible heat, <i>H</i>, and latent heat, LE) and CO2 (<i>F</i>CO2) represent the "true" ﬂux plus or minus potential random and systematic measurement errors. Here, we use data ...
• #### North American terrestrial CO2 uptake largely offset by CH4 and N2O emissions: toward a full accounting of the greenhouse gas budget ﻿

(Springer Netherlands, 2014)
The terrestrial ecosystems of North America have been identified as a sink of atmospheric CO2 though there is no consensus on the magnitude. However, the emissions of non-CO2 greenhouse gases (CH4 and N2O) may offset or ...
• #### Nucleation and Growth of HNO3.3H2O Particles in the Polar Stratosphere ﻿

(American Meteorological Society, 1990)
Growth of nitric acid trihydrate (NAT) particles on background stratospheric aerosols is examined for an isolated air parcel cooled at a uniform rate. The free energy barrier against nucleation and rates of cooling are ...
• #### Patterns of Water and Heat Flux Across a Biome Gradient From Tropical Forest to Savanna in Brazil ﻿

(American Geophysical Union, 2009)
We investigated the seasonal patterns of water vapor and sensible heat flux along a tropical biome gradient from forest to savanna. We analyzed data from a network of flux towers in Brazil that were operated within the ...
• #### Photochemical Production of Carboxylic Acids in a Remote Continental Atmosphere ﻿

Model calculations are conducted to investigate the production of carboxylic acids from photochemical decomposition of isoprene, one of the main natural hydrocarbons emitted from vegetation. Both gas-phase and aqueous-phase ...
• #### Photochemistry of biogenic emissions over the Amazon forest ﻿

(Wiley-Blackwell, 1988)
The boundary layer chemistry over the Amazon forest during the dry season is simulated with a photochemical model. Results are in good agreement with measurements of isoprene, NO, ozone, and organic acids. Photochemical ...
• #### Precision requirements for space-based X CO 2 data ﻿

(American Geophysical Union, 2007)
Precision requirements are determined for space-based column-averaged CO2 dry air mole fraction image data. These requirements result from an assessment of spatial and temporal gradients in image the relationship between ...