Now showing items 21-33 of 33

• #### Seasonal budgets of reactive nitrogen species and ozone over the United States, and export fluxes to the global atmosphere ﻿

(Wiley-Blackwell, 1998)
A three-dimensional, continental-scale photochemical model is used to investigate seasonal budgets of O3 and NOy species (including NOx and its oxidation products) in the boundary layer over the United States and to estimate ...
• #### Seasonal fluxes of carbonyl sulfide in a midlatitude forest ﻿

(Proceedings of the National Academy of Sciences, 2015)
Carbonyl sulfide (OCS), the most abundant sulfur gas in the atmosphere, has a summer minimum associated with uptake by vegetation and soils, closely correlated with CO2. We report the first direct measurements to our ...
• #### Seasonal transition from NO x - to hydrocarbon-limited conditions for ozone production over the eastern United States in September ﻿

(Wiley-Blackwell, 1995)
Concentrations of O3, CO, NO, total reactive nitrogen oxides (NOy), H2O2, and HCHO were measured from September 4 to October 1, 1990, at a mountain ridge site in Shenandoah National Park, Virginia. The data show evidence ...
• #### Seasonal variation of the ozone production efficiency per unit NOx at Harvard Forest, Massachusetts ﻿

(Wiley-Blackwell, 1996)
Weekly values of the net O3 production efficiency (OPE), defined as the net number of O3 molecules produced per molecule of NOx (NO + NO2) consumed, are estimated from a 1990–1994 record of O3, NOx, NOy, CO, and C2H2 ...
• #### Shenandoah Cloud and Photochemistry Experiment (SCAPE): Overview ﻿

(Wiley-Blackwell, 1995)
The Shenandoah Cloud and Photochemistry Experiment (SCAPE) investigated the chemistry of the atmosphere at a high-elevation forested site in central Virginia with particular focus on the factors controlling concentrations ...
• #### Simultaneous Measurements of Atmospheric HONO and NO2 via Absorption Spectroscopy using Tunable Mid-Infrared Continuous-wave Quantum Cascade Lasers ﻿

(Springer Verlag, 2011)
Nitrous acid (HONO) is important as a significant source of hydroxyl radical (OH) in the troposphere and as a potent indoor air pollutant. It is thought to be generated in both environments via heterogeneous reactions ...
• #### Terrestrial biosphere models need better representation of vegetation phenology: results from the North American Carbon Program Site Synthesis ﻿

(Wiley Blackwell (Blackwell Publishing), 2012)
Phenology, by controlling the seasonal activity of vegetation on the land surface, plays a fundamental role in regulating photosynthesis and other ecosystem processes, as well as competitive interactions and feedbacks to ...
• #### Top-down estimate of China's black carbon emissions using surface observations: Sensitivity to observation representativeness and transport model error ﻿

(Wiley-Blackwell, 2013)
This study examines the sensitivity of “top-down” quantification of Chinese black carbon (BC) emissions to the temporal resolution of surface observations and to the transport model error associated with the grid resolution ...
• #### Tracking forest phenology and seasonal physiology using digital repeat photography: a critical assessment ﻿

(Ecological Society of America, 2014)
Digital repeat photography is becoming widely used for near-surface remote sensing of vegetation. Canopy greenness, which has been used extensively for phenological applications, can be readily quantified from camera images. ...
• #### Transport and oxidation of SO2 in a stagnant foggy valley ﻿

(Elsevier BV, 1986)
The fate of SO2 emitted in the San Joaquin Valley of California under stagnant foggy conditions was determined by the release of an inert tracer and the concurrent monitoring of SO2 and SO42− concentrations. At night, SO2 ...
• #### Variations in Atmospheric $CO_2$ Mixing Ratios across a Boston, MA Urban to Rural Gradient ﻿

(MDPI AG, 2013)
Urban areas are directly or indirectly responsible for the majority of anthropogenic $CO_2$ emissions. In this study, we characterize observed atmospheric $CO_2$ mixing ratios and estimated $CO_2$ fluxes at three ...
• #### Variations of $O_3$ and CO in Summertime at a Rural Site Near Beijing ﻿

(Copernicus Publications on behalf of the European Geosciences Union, 2008)
Large intra-season differences in mixing ratios of CO and $O_3$ were detected at Miyun, a rural site north of Beijing, in summer 2006. Despite an increase in mean daytime mixing ratio of CO from 500 ppbv in June to 700 ...
• #### Year round measurements of O3 and CO at a rural site near Beijing: variations in their correlations ﻿

(Co-Action Publishing, 2010)
We examine seasonal variations of carbon monoxide (CO), ozone (O3), and their relationships observed over the course of 3 yr (2005–2007) at Miyun, a rural site 100 km north of Beijing. Monthly mean afternoon mixing ratios ...