A5083713276- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Meteorological Phenomena and Simulations
- Climate variability and models
- Methane Hydrates and Related Phenomena
- Spectroscopy and Laser Applications
- Air Quality Monitoring and Forecasting
- Hydrocarbon exploration and reservoir analysis
- Peatlands and Wetlands Ecology
- Climate change and permafrost
- Air Quality and Health Impacts
- Carbon Dioxide Capture Technologies
- Plant Water Relations and Carbon Dynamics
- Geochemistry and Geologic Mapping
- CO2 Sequestration and Geologic Interactions
- Cryospheric studies and observations
- Vehicle emissions and performance
- Climate Change Policy and Economics
- Calibration and Measurement Techniques
- Odor and Emission Control Technologies
- Reservoir Engineering and Simulation Methods
- Forest Management and Policy
- Forest ecology and management
- Scientific Research and Discoveries
Cooperative Institute for Research in Environmental Sciences
1987-2024
University of Colorado Boulder
1988-2024
NOAA Chemical Sciences Laboratory
2024
National Oceanic and Atmospheric Administration
1997-2023
NOAA Earth System Research Laboratory
2010-2021
World Meteorological Organization
2017
Science Research Laboratory
2017
The first 12 years (1974–1985) of continuous atmospheric CO 2 measurements from the NOAA GMCC program at Mauna Loa Observatory in Hawaii are analyzed. Hourly and daily variations concentration due to local sources sinks described, with subsequent selection data representing background concentrations. A digital filtering technique using fast Fourier transform low‐pass filters was used smooth selected separate seasonal cycle long‐term increase . amplitude found be increasing a rate 0.05±0.02...
The distribution and variations of atmospheric CO 2 from 1981 to 1992 were determined by measuring mixing ratios in samples collected weekly at a cooperative global air sampling network. results constitute the most geographically extensive, carefully calibrated, internally consistent data set available. Analysis reveals that growth rate has declined peak ∼2.5 ppm yr −1 1987–1988 ∼0.6 1992. In we find no increase 30° 90°N. Variations fossil fuel emissions cannot explain this result. north...
Sixteen mixtures of methane (CH 4 ) in dry air were prepared using a gravimetric technique to define CH standard gas scale covering the nominal range 300–2600 nmol mol −1 . It is designed be suitable for measurements ranging from those extracted glacial ice contemporary background atmospheric conditions. All standards passivated, 5.9 L high‐pressure aluminum cylinders. Methane mole fractions determined by chromatography with flame ionization detection, where repeatability measurement...
Abstract Seasonal spatial and temporal gradients for the CO 2 mole fraction over North America are examined by creating a climatology from data collected 2004–2013 NOAA/ESRL Global Greenhouse Gas Reference Network Aircraft Program relative to trends observed at Mauna Loa Observatory. The analyzed measurements of air samples in specially fabricated flask packages frequencies days months 22 sites continental shipped back Boulder, Colorado, analysis. These calibrated World Meteorological...
Significance Rising arctic temperatures could mobilize reservoirs of soil organic carbon trapped in permafrost. We present the first quantitative evidence for large, regional-scale early winter respiration flux, which more than offsets uptake summer Arctic. Data from National Oceanic and Atmospheric Administration’s Barrow station indicate that October through December emissions CO 2 surrounding tundra increased by 73% since 1975, supporting view rising have made Arctic ecosystems a net...
We study the drivers behind global atmospheric methane (CH
CO 2 data obtained from discrete sampling during 1968–1982 at 23 National Oceanic and Atmospheric Administration/Geophysical Monitoring for Climatic Change foreign cooperative stations are presented, together with a description of the measurement program quality. Monthly, seasonal, annual concentrations determined by individual select (background) data. Temporal spatial global distributions yield seasonal latitudinal gradients, abundances, airborne fractions, cycle amplitudes phases,...
The carbon dioxide concentration has been measured in air samples collected approximately once per week at 22 globally distributed sites during 1981-84. All were analyzed on the same non-dispersive infrared analyzer apparatus NOAA/GMCC laboratory Boulder. concentrations are directly traceable to WMO primary C02 standards. Samples which do not contain well-mixed, regionally representative or have contaminated subsequent sampling, identified. selected data using an objective curve fitting...
Long-term atmospheric CO2 mole fraction and δ13CO2 observations over North America document persistent responses to the El Niño-Southern Oscillation. We estimate these corresponded 0.61 (0.45 0.79) PgC year-1 more American carbon uptake during Niño than La Niña between 2007 2015, partially offsetting increases of net tropical biosphere-to-atmosphere flux around Niño. Anomalies in derived ecosystem exchange (NEE) display strong but opposite correlations with surface air temperature seasons,...
Significance Global-scale observations suggest large unexplained emissions of the ozone-depleting chemical carbon tetrachloride (CCl 4 ) despite stringent limits on its production for dispersive uses many years. Identifying sources continued CCl emission is necessary before steps can be taken to accelerate decline and limit future ozone depletion. Results from an extensive air sampling network over United States indicate with a similar distribution but much larger magnitude than industrial...
Abstract Ozone depleting substances (ODSs) controlled by the Montreal Protocol are potent greenhouse gases (GHGs), as their substitutes, hydrofluorocarbons (HFCs). Here we provide for first time a comprehensive estimate of U.S. emissions ODSs and HFCs based on precise measurements in discrete air samples from across North America remote atmosphere. Derived show spatial seasonal variations qualitatively consistent with known uses largely confirm Environmental Protection Agency (EPA) national...
Abstract North American nitrous oxide (N 2 O) emissions of 1.6 ± 0.3 Tg N/yr over 2008–2014 are estimated using the CarbonTracker‐Lagrange regional inversion framework. The N O largely consistent with EDGAR (Emission Database for Global Atmospheric Research) global inventory and results atmospheric inversions but offer more spatial temporal detail America. Emissions strongest from Midwestern Corn/Soybean Belt, which accounts nearly one third total source. maximum in spring/early summer, a...
Abstract Recent studies show conflicting estimates of trends in methane (CH 4 ) emissions from oil and natural gas (ONG) operations the United States. We analyze atmospheric CH measurements 20 North American sites National Oceanic Atmospheric Administration Global Greenhouse Gas Reference Network determined for 2006–2015. Using vertical gradients as an indicator regional surface emissions, we find no significant increase at most modest increases three heavily influenced by ONG activities....
Abstract. Changes in atmospheric methane abundance have implications for both chemistry and climate as is a strong greenhouse gas an important precursor tropospheric ozone. A better understanding of the drivers trends variability over recent past therefore critical building confidence projections future levels. In this work, representation model AM4.1 improved by optimizing total emissions (to annual mean 580±34 Tg yr−1) to match surface observations 1980–2017. The simulations with optimized...
In the Arctic and Boreal region (ABR) where warming is especially pronounced, increase of gross primary production (GPP) has been suggested as an important driver for atmospheric CO2 seasonal cycle amplitude (SCA). However, role GPP relative to changes in ecosystem respiration (ER) remains unclear, largely due our inability quantify these fluxes on regional scales. Here, we use carbonyl sulfide (COS) measurements provide observation-based estimates over North American ABR. Our annual...
Understanding tropical rainforest carbon exchange and its response to heat drought is critical for quantifying the effects of climate change on ecosystems, including global climate-carbon feedbacks. Of particular importance budget net biome CO2 with atmosphere (NBE), which represents nonfire fluxes into out biomass soils. Subannual sub-Basin Amazon NBE estimates have relied heavily process-based biosphere models, despite lack model agreement plot-scale observations. We present a new analysis...
Abstract U.S. national and regional emissions of HFC‐134a are derived for 2008–2012 based on atmospheric observations from ground aircraft sites across the a newly developed inverse model. Synthetic data experiments were first conducted to optimize model assimilation design assess model‐data mismatch errors prior flux error covariances computed using maximum likelihood estimation technique. The synthetic also tested sensitivity range assumed emissions, with goal designing system that was...
Abstract. Sulfur hexafluoride (SF6) is the most potent greenhouse gas (GHG), and its atmospheric abundance, albeit small, has been increasing rapidly. Although SF6 used to assess transport modeling emissions influence climate for millennia, emission magnitudes distributions have substantial uncertainties. In this study, we NOAA's ground-based airborne measurements of estimate from United States between 2007 2018. Our results suggest a decline US emissions, trend also reported in...
A high‐precision manometric system has been developed for absolute calibrations of CO 2 ‐in‐air mixture gas. This report describes the principle calibration method and evaluates performance apparatus. The test results show that reproducibility calibrating gas mixtures is within ±0.1 μmol mol −1 in atmospheric concentration range 300 to 400 . Preliminary measurements indicate agreement with World Meteorological Organization mole fraction scale, widely used monitoring, also same range.
Abstract. We have developed a method to calculate the fractional distribution of CO2 across all its component isotopologues based on measured δ13C and δ18O values. The can be used with known total amount substance fraction (mole fraction) each isotopologue in air individually. technique is applicable any molecule where isotopologue-specific values are desired. it new calibration system account for isotopic differences among primary standards that define WMO X2007 CO2-in-air scale between...