Research Data

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Open Access
2010 C2H6 global emission inventory
(Colorado State University. Libraries, 2016) Zitely, Tzompa-Sosa
Recent measurements over the Northern Hemisphere indicate that the long-term decline in the atmospheric burden of ethane (C2H6) has ended, and the abundance increased dramatically between 2010 and 2014. The rise in the abundance of C2H6 has been attributed to oil and natural gas extraction in North America. Existing global C2H6 emission inventories are based on outdated activity maps that do not account for current oil and natural gas exploitation regions. We present an updated global C2H6 emission inventory based on 2010 satellite-derived CH4 fluxes with adjusted C2H6 emissions over the U.S. from the National Emission Inventory (NEI 2011). We contrast our global 2010 C2H6 emission inventory with one developed for 2001. The C2H6 difference between global anthropogenic emissions is subtle (7.9 versus 7.2 Tg yr-1), but the spatial distribution of the emissions is distinct. In the 2010 C2H6 inventory, fossil fuel sources in the Northern Hemisphere represent half of global C2H6 emissions and 95% of global fossil fuel emissions. Over the U.S., un-adjusted NEI 2011 C2H6 emissions produce mixing ratios that are 14-50 % of those observed by aircraft observations (2008-2014). When the NEI 2011 C2H6 emission totals are scaled by a factor of 1.4, the model largely reproduces a regional suite of observations, with the exception of the central U.S., where it continues to under-predict observed mixing ratios in the lower troposphere. We estimate monthly mean contributions of fossil fuel C2H6 emissions to ozone and peroxyacetyl nitrate surface mixing ratios over North America of ~1% and ~8%, respectively.
Open Access
Anomalous integrated water vapor transport-based atmospheric river detection algorithm
(Colorado State University. Libraries, 2016) Mundhenk, Bryan D.; Barnes, Elizabeth A.; Maloney, Eric D.
Atmospheric rivers (ARs) are often characterized as transient, plume-like structures of focused tropospheric water vapor and intense low-level winds that contribute substantially to the atmospheric branch of the hydrologic cycle. Here, we provide an abridged version of an AR detection algorithm, written in the Python 2.7 programming language, that was developed to facilitate climatological and dynamical analyses of ARs. This algorithm employs a unique approach of detecting AR-like features from within gridded fields of anomalous integrated water vapor transport. The use of anomalies was found to be efficient and to benefit automated feature detection in large spatial (i.e., North Pacific) and temporal (i.e., sub-daily across all seasons) domains.
Open Access
Atmospheric implications of large light alkane emissions from the U.S. oil and gas industry
(Colorado State University. Libraries, 2018) Tzompa-Sosa, Zitely A.
Emissions of non-methane light alkanes from the U.S. oil and gas sector have changed rapidly over the last decade. We use a nested GEOS-Chem simulation driven by updated atmospheric abundances of light alkanes over the U.S., and 2) estimate the contribution of emissions from the U.S. oil and gas industry to these patterns. The oil and gas sector in the updated NEI 2011 contributes >80% of the total U.S. emissions of ethane (C2H6) and propane (C3H8), and emissions of these species are largest in the central U.S. Observed mixing ratios of C2-C5 alkanes show enhancements over the central U.S. below 2 km. A nested GEOS-Chem simulation underpredicts observed C3H8 mixing ratios in the boundary layer over several U.S. regions and the relative underprediction is not consistent, suggesting C3H8 emissions should receive more attention moving forward. Our decision to consider only C4-C5 alkane emissions as a single lumped species produces a geographic distribution similar to observations. Due to the increasing importance of oil and gas emissions in the U.S., we recommend continued support of existing long-term measurements of C2-C5 alkanes. We suggest additional monitoring of C2-C5 alkanes downwind of northeastern Colorado, Wyoming and western North Dakota to capture changes in these regions. The atmospheric chemistry modeling community should also evaluate whether chemical mechanisms that lump larger alkanes are sufficient to understand air quality issues in regions with large emissions of these species.
Open Access
Calwater2 scanning flow CCN measurements at Bodega Bay Marine Laboratory
(Colorado State University. Libraries, 2015) Kreidenweis, Sonia M.; Atwood, Samuel A.; DeMott, Paul J.
Scanning flow CCN measurements were conducted at the Bodega Bay Marine Laboratory (BML) as part of the Calwater2 campaign.
Open Access
Carlsbad Caverns National Park Air Quality Study 2019
(Colorado State University. Libraries, 2022) Sullivan, Amy P.; Naimie, Lillian E.; Benedict, K. B.; Prenni, Anthony J.; Sive, B. C.; Fischer, Emily V.; Pollack, Ilana; Collett, Jeffrey; Schichtel, Bret A.
Carlsbad Caverns National Park in southeastern New Mexico is adjacent to the Permian Basin, one of the most productive oil and gas regions in the country. The 2019 Carlsbad Caverns Air Quality Study (CarCavAQS) was designed to examine the influence of regional sources, including urban emissions, oil and gas development, wildfires, and soil dust on air quality in the park. Field measurements of aerosols, trace gases, and deposition were conducted from 25 July through 5 September 2019.
Open Access
Characterizing emissions from natural gas drilling and well completion operations in Garfield County, CO
(Colorado State University. Libraries, 2016) Collett, Jeffrey; Hecobian, Arsineh; Ham, Jay; Pierce, Jeff; Clements, Andrea; Shonkwiler, Kira; Zhou, Yong; Desyaterik, Yuri; MacDonald, Landan; Wells, Bradley; Hilliard, Noel
This study was designed to characterize and quantify emission rates and dispersion of air toxics, ozone precursors, and greenhouse gases from unconventional natural gas well development activities in Garfield County, CO, located on top of a geological formation known as the Piceance Basin. Particular focus was placed on quantifying emissions of individual volatile organic compounds (VOCs) and methane during well drilling, hydraulic fracturing ("fracking"), and flowback. While some prior studies have measured VOC or methane concentrations near well development operations, ambient concentrations are strongly dependent not only on emission rates but also on sampling location and meteorological conditions, which greatly affect downwind dispersion and dilution. By characterizing emission rates directly, results from this study can be used to predict downwind concentration fields for any location of interest under a wide range of weather conditions. Emission rates were determined using a tracer ratio method (TRM). In this method, the rate of emission of a compound of interest (e.g., g s-1 of benzene) is determined as the product of a known tracer emission rate multiplied by the ratio of the background-corrected concentrations of the compound of interest and the tracer. Acetylene was selected as a tracer gas and its controlled release co-located with the main source of emissions on studied well pads. Real-time methane and acetylene concentrations and three minute integrated whole air sample canisters for VOC analysis were collected downwind of the release location. Meteorological data were collected at two heights (3 m and 10 m) near the well pad. Upwind acetylene, methane, and VOC concentrations were determined for background correction. The canisters were analyzed for a large suite of VOCs using gas chromatography with flame ionization detection. The study results provide novel information concerning emissions from natural gas drilling and completion activities in Garfield County, CO and are some of the first measurements of this type in any U.S. basin. Overall, 21 emission experiments were conducted from 2013-2015. Several sets of 2 to 5 canisters were collected at different times during each experiment, in addition to an upwind background sample per experiment. Using the TRM, each canister in the plume provides an independent measure of VOC emission rates. 28-48 VOCs are reported for each canister, along with real-time methane and acetylene data collected during each experiment. Using the TRM the emission rates of methane and individual VOCs are calculated and reported.The emission rates and field observations were used to conduct air dispersion (using the EPA's AERMOD model) simulations to: (1) evaluate AERMOD's accuracy in predicting observed, near-field dispersion of VOCs in Garfield County, CO and (2) predict concentration fields, as a function of emission rate, for dispersion of a hypothetical compound under a range of local meteorological conditions at a site with terrain similar to that observed in Garfield County. While not perfectly designed for prediction of the short-term concentration fields measured in the study, AERMOD did a reasonable job predicting the observed extent of dispersion across several field experiments. Moreover, emission rate ranges determined by activity type in this study can be used in a wide range of future simulations with AERMOD or other models to simulate downwind concentration fields relevant to understanding potential local health and air quality impacts associated with well development activities in Garfield County.
Open Access
Cross-Track Infrared Sounder (CrIS) Peroxyacetyl Nitrate (PAN) and Carbon Monoxide (CO) retrievals for the 2018 wildfire season over the western U.S.
(Colorado State University. Libraries, 2021) Juncosa Calahorrano, Julieta Fernanda
We use new peroxyacetyl nitrate (PAN) observations from the Cross-Track Infrared Sounder (CrIS) on the Suomi National Polar-orbiting Partnership satellite to investigate PAN over the western U.S. during the summer 2018 North American wildfire season. This period coincides with the Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN). When combined with favorable background conditions, the resolution and sensitivity of CrIS is sufficient to observe PAN production in plumes. CrIS PAN normalized excess mixing ratios (NEMRs) in the Pole Creek Fire increase from 0.2% to 0.4% within 3-4 hours of physical aging, consistent with NEMRs calculated from WE-CAN observations. CrIS is also able to detect PAN and CO enhancements in plumes that have been transported hours to days downwind. On average for the study period, 24-56% of PAN in the free troposphere during the afternoon over the western U.S. can be attributed to fires.
Open Access
Data associated with "Assessing Rain Drop Breakup Parameterizations using Disdrometer Observations"
(Colorado State University. Libraries, 2022) Saleeby, Stephen; Dolan, Brenda; Bukowski, Jennie
An intercomparison of rain drop mean diameter frequency distribution (RDFD) is performed for numerical simulations of precipitating cloud systems using an array of models and microphysics schemes. This includes results from the Regional Atmospheric Modeling System (RAMS) double-moment microphysics, the Hebrew University Cloud Model bin microphysics (HUCM) interfaced to the RAMS parent model, and the Weather Research and Forecasting Model (WRF) with the Thompson, Morrison, Double Moment 6-Class (WDM6), and National Severe Storm Laboratory (NSSL) double-moment schemes. Simulations are examined with respect to the rain drop size distribution (DSD) volume-number mean diameter (Dm) and intercept parameter (Nw). When compared to a suite of disdrometer observations, the RDFD resulting from each microphysics scheme exhibits varying degrees of mean drop size constraints and peaks in the frequency distribution of Dm. A more detailed investigation of the peaked RDFD from the RAMS simulations suggests that the parameterization of rain drop collisional breakup can impose strong limitations on the evolution of simulated drop growth. As such, a summary and comparison of the drop breakup parameterizations among the forementioned microphysics schemes is presented. While some drop breakup parameterizations are adjusted toward the observations by modifying the threshold diameter for the onset of breakup, this study explores the use of a modified maximum breakup efficiency. This method permits the parameterization to retain its threshold breakup diameter, while limiting the strength of drop breakup and permitting a broader range of drop sizes. As a result, the simulated mean drop sizes are in better agreement with observations.
Open Access
Data associated with "Constraining aerosol phase function using dual-view geostationary satellites"
(Colorado State University. Libraries, 2021) Bian, Qijing; Kreidenweis, Sonia; Chiu, J. Christine; Miller, Steven D.; Xu, Xiaoguang; Wang, Jun; Kahn, Ralph A.; Limbacher, James A.; Remer, Lorraine A.; Levy, Robert C.
Passive satellite observations play an important role in monitoring global aerosol properties and helping quantify aerosol radiative forcing in the climate system. The quality of aerosol retrievals from the satellite platform relies on well-calibrated radiance measurements from multiple spectral bands, and the availability of appropriate particle optical models. Inaccurate scattering phase function assumptions can introduce large retrieval errors. High-spatial resolution, dual-view observations from the Advanced Baseline Imagers (ABI) on board the two most recent Geostationary Operational Environmental Satellites (GOES), East and West, provide a unique opportunity to better constrain the aerosol phase function. Using dual GOES reflectance measurements for a dust event in the Gulf of Mexico in 2019, we demonstrate how a first-guess phase function can be reconstructed by considering the variations in observed scattering angle throughout the day. Using the reconstructed phase function, aerosol optical depth retrievals from the two satellites are self-consistent and agree well with surface-based optical depth estimates. We evaluate our methodology and reconstructed phase function against independent retrievals made from low-Earth-orbit multi-angle observations for a different dust event in 2020. Our new aerosol optical depth retrievals have a root-mean-square-difference of 0.019– 0.047. Furthermore, the retrievals between the two geostationary satellites for this case agree within about 0.059±0.072, as compared to larger discrepancies between the operational GOES products at times, which do not employ the dual-view technique.
Open Access
Data associated with "Convective distribution of dust over the Arabian Peninsula: the impact of model resolution"
(Colorado State University. Libraries, 2020) Bukowski, Jennie; van den Heever, Sue
Along the coasts of the Arabian Peninsula, convective dust storms are a considerable source of mineral dust to the atmosphere. Reliable predictions of convective dust events are necessary to determine their effects on air quality, visibility, and the radiation budget. In this study, the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) is used to simulate a 2016 summertime dust event over the Arabian Peninsula and examine the variability in dust fields and associated vertical transport due to the choice of convective parameterization and explicit versus parameterized convection. Simulations are run at 45 km and 15 km grid spacing with multiple cumulus parameterizations, and are compared to a 3 km simulation that permits explicit convective processes. Five separate cumulus parameterizations at 15 km grid spacing were tested to quantify the spread across different parameterizations. Finally, the impact these variations have on radiation, specifically aerosol heating rates is also investigated. On average, in these simulations the explicit case produces higher quantities of dust than the parameterized cases in terms of dust uplift potential, vertical dust concentrations, and vertical dust fluxes. Major drivers of this discrepancy between the simulations stem from the explicit case exhibiting higher surface windspeeds during convective activity, lower dust emission wind threshold velocities due to drier soil, and more frequent, stronger vertical velocities which transport dust aloft and increase the atmospheric lifetime of these particles. For aerosol heating rates in the lowest levels, the shortwave effect prevails in the explicit case with a net cooling effect, whereas a longwave net warming effect is present in the parameterized cases. The spread in dust concentrations across cumulus parameterizations at the same grid resolution (15 km) is an order of magnitude lower than the impact of moving from parameterized to explicit convection. We conclude that tuning dust emissions in coarse resolution simulations can only improve the results to first-order and cannot fully rectify the discrepancies originating from disparities in the representation of convective dust transport.
Open Access
Data associated with "Environmental controls on tropical sea breeze convection and resulting aerosol redistribution"
(Colorado State University. Libraries, 2020) Park, Jungmin Minnie; van den Heever, Susan C.; Igel, Adele L.; Grant, Leah D.; Johnson, Jill S.; Saleeby, Stephen M.; Miller, Steven D.; Reid, Jeffery S.
Sea breeze fronts propagate inland from the coastline, driving convective initiation and aerosol redistribution. Forecasting sea breezes is challenging due to uncertainties in the initial conditions, as well as the covariance and interaction of various meteorological and surface parameters. Using the Regional Atmospheric Modeling System (RAMS) coupled to an interactive land-surface model, we conduct an ensemble of 130 idealized cloud-resolving simulations by simultaneously perturbing six atmospheric and four surface parameters describing the initial conditions. To identify the key parameters impacting the inland characteristics and the intensity of the sea breeze convection in a tropical rainforest, we apply statistical emulation and variance-based sensitivity analysis techniques. This study extends a previous study which explored the impacts of various parameters on sea breeze characteristics in arid environments devoid of moist convection. Wind speed is identified as the main contributor to the inland extent, similar to the arid environment study. However, the relative impacts of surface properties on the inland extent are less significant in the moist environment where land-surface heating can be suppressed via moist convective processes and vegetation-atmosphere interactions. Two sea breeze-initiated convection regimes are also identified: shallow and deep. Over the shallow regime, where convective available potential energy (CAPE) is limited, the inversion layer strength is the primary control of the convective intensity. Over the deep regime, boundary layer temperature exerts a robust control over the CAPE and hence the convective intensity. The potential vertical redistribution of aerosols is closely related to the convective intensity.
Open Access
Data Associated with "The Key Role of Cloud-Climate Coupling in Extratropical Sea Surface Temperature Variability"
(Colorado State University. Libraries, 2021) Boehm, Chloe; Thompson, David W.J.
Cloud radiative effects have long been known to play a key role in governing the mean climate. In recent years, it has become clear that they also contribute to climate variability in the tropics. Here we build on recent work and probe the role of cloud radiative effects in extratropical sea-surface temperature (SST) variability. The impact of cloud radiative effects on climate variability is explored in ‘cloud-locking’ simulations run on an Earth System Model. The method involves comparing the output from two climate simulations: one in which clouds are coupled to the atmospheric circulation and another in which clouds are prescribed and thus decoupled from the flow. The results reveal that coupling between cloud radiative effects and the atmospheric circulation leads to widespread increases in the amplitudes of extratropical SST variability from monthly to decadal timescales. Notably, the amplitude of monthly to decadal variability over both the North Atlantic and North Pacific oceans is between ~25-40% larger when clouds are coupled to the circulation. The increases are consistent with the ‘reddening’ of cloud shortwave radiative effects that arises when clouds interact with the large-scale circulation. The results suggest that a notable fraction of observed Northern Hemisphere sea-surface temperature variability - including that associated with North Pacific and North Atlantic decadal variability - is due to cloud-circulation coupling.
Open Access
Data associated with the manuscript Using TES retrievals to investigate PAN in North American biomass burning plumes
(Colorado State University. Libraries, 2017) Fischer, Emily V.; Zhu, Liye; Payne, Vivienne H; Brey, Steven
Peroxyacyl nitrate (PAN) is a critical atmospheric reservoir for nitrogen oxide radicals, and it plays a lead role in their redistribution in the troposphere. We analyze new Tropospheric Emission Spectrometer (TES) PAN observations over North America during July 2006 to 2009. Using aircraft observations from the Colorado Front Range, we demonstrate that TES can be sensitive to elevated PAN in the boundary layer (~750 hPa) even in the presence of clouds. In situ observations have shown that wildfire emissions can rapidly produce PAN, and PAN decomposition is an important component of ozone production in smoke plumes. We identify smoke-impacted TES PAN retrievals by co-location with NOAA Hazard Mapping System (HMS) smoke plumes. Depending on the year, 15 – 32 % of cases where elevated PAN is identified in TES observations (retrievals with DOF > 0.6) overlap smoke plumes during July. Of all the retrievals attempted in July 2006 to July 2009, the percent associated with smoke is 18%. A case study of smoke transport in July 2007 illustrates that PAN enhancements associated with HMS smoke plumes can be connected to fire complexes, providing evidence that TES is sufficiently sensitive to measure elevated PAN several days downwind of major fires. Using a subset of retrievals with TES 510 hPa carbon monoxide (CO) > 150 ppbv, and multiple estimates of background PAN, we calculate enhancement ratios for tropospheric average PAN relative to CO in smoke-impacted retrievals. Most of the TES-based enhancement ratios fall within the range calculated from in situ measurements.
Open Access
Data associated with “Adapting the COSP Radar Simulator to Compare GCM Output and GPM Precipitation Radar Observations”
(Colorado State University. Libraries, 2021) Riley Dellaripa, Emily M.; Funk, Aaron; Schumacher, Courtney; Bai, Hedanqiu; Spangehl, Thomas
Comparisons of precipitation between general circulation models (GCMs) and observations are often confounded by a mismatch between model output and instrument measurements, including variable type and temporal and spatial resolution. To mitigate these differences, the radar-simulator Quickbeam within the Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulator Package (COSP) simulates reflectivity from model variables at the sub-grid scale. This work adapts Quickbeam to the dual-frequency Precipitation Radar (DPR) onboard the Global Precipitation Measurement (GPM) satellite. The longer wavelength of the DPR is used to evaluate moderate-to-heavy precipitation in GCMs, which is missed when Quickbeam is used as a cloud radar simulator. Latitudinal and land/ocean comparisons are made between COSP output from the Community Atmospheric Model version 5 (CAM5) and DPR data. Additionally, this work improves the COSP sub-grid algorithm by applying a more realistic, non-deterministic approach to assigning GCM grid box convective cloud cover when convective cloud is not provided as a model output. Instead of assuming a static 5% convective cloud coverage, DPR convective precipitation coverage is used as a proxy for convective cloud coverage. For example, DPR observations show that convective rain typically only covers about 1% of a 2°grid box, but that the median convective rain area increases to over 10% in heavy rain cases. In our CAM5 tests, the updated sub-grid algorithm improved the comparison between reflectivity distributions when the convective cloud cover is provided versus the default 5% convective cloud cover assumption.
Open Access
Data associated with “Direct Radiative Effects in Haboobs”
(Colorado State University. Libraries, 2021) Bukowski, Jennie; van den Heever, Sue
Convective dust storms, or haboobs, form when strong surface winds loft loose soils in convective storm outflow boundaries. Haboobs are a public safety hazard and can cause a near instantaneous loss of visibility, inimical air quality, and contribute significantly to regional dust and radiation budgets. Nevertheless, reliable predictions of convective dust events are inhibited by a lack of understanding regarding the complex and non-linear interactions between density currents, or convective cold pools, and dust radiative effects. In this paper, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is utilized to simulate the effect dust radiation interactions have on a long-lived haboob case study that spans three distinct radiative regimes: day (high shortwave), evening (low shortwave), and night (longwave only). A sophisticated algorithm is used to track and identify the numerous convective cold pool boundaries in the simulations and assemble statistics that represent the impact of dust radiative effects. To first order, dust scattering of shortwave radiation in the day leads to a colder, dustier, and faster moving convective cold pool. In the transition period of early evening, the shortwave effects diminish while longwave dust absorption leads to warmer, slower density currents that loft less dust as they propagate onward. At night, the haboob is again warmer due to dust absorption, but gustier in the more stable nocturnal surface layer, leading to enhanced dust emissions.
Open Access
Data behind Figures in "Peroxy acetyl nitrate (PAN) measurements at northern midlatitude mountain sites in April: a constraint on continental source–receptor relationships"
(Colorado State University. Libraries, 2018) Fiore, Arlene M.; Fischer, Emily V.; Milly, George P.; Pandey Deolal, Shubha; Wild, Oliver; Jaffe, Dan; Staehelin, Johannes; Clifton, Olivia E.; Bergmann, Dan; Collins, William; Dentener, Frank; Doherty, Ruth M.; Duncan, Bryan N.; Fischer, Bernd; Gilge, Stefan; Hess, Peter G.; Horowitz, Larry W.; Lupu, Alexandru; MacKenzie, Ian; Park, Rokjin; Ries, Ludwig; Sanderson, Michael G.; Schultz, Martin G.; Shindell, Drew T.; Steinbacher, Martin; Stevenson, David S.; Szopa, Sophie; Zellweger, Christoph; Zeng, Guang
Abundance-based model evaluations with observations provide critical tests for the simulated mean state in models of intercontinental pollution transport, and under certain conditions may also offer constraints on model responses to emission changes. We compile multiyear measurements of peroxy acetyl nitrate (PAN) available from five mountaintop sites and apply them in a proof-of-concept approach that exploits an ensemble of global chemical transport models (HTAP1) to identify an observational "emergent constraint". In April, when the signal from anthropogenic emissions on PAN is strongest, simulated PAN at northern midlatitude mountaintops correlates strongly with PAN source–receptor relationships (the response to 20 % reductions in precursor emissions within northern midlatitude continents; hereafter, SRRs). This finding implies that PAN measurements can provide constraints on PAN SRRs by limiting the SRR range to that spanned by the subset of models simulating PAN within the observed range. In some cases, regional anthropogenic volatile organic compound (AVOC) emissions, tracers of transport from different source regions, and SRRs for ozone also correlate with PAN SRRs. Given the large observed interannual variability in the limited available datasets, establishing strong constraints will require matching meteorology in the models to the PAN measurements. Application of this evaluation approach to the chemistry– climate models used to project changes in atmospheric composition will require routine, long-term mountaintop PAN measurements to discern both the climatological SRR signal and its interannual variability.
Open Access
Data collected during the pilot campaign of the citizen-enabled aerosol measurements for satellites (CEAMS) network in northern Colorado
(Colorado State University. Libraries, 2019) Ford, Bonne; Pierce, Jeffrey R.; Wendt, Eric; Long, Marilee; Jathar, Shantanu; Mehaffy, John; Tryner, Jessica; Quinn, Casey; van Zyl, Lizette; L'Orange, Christian; Miller-Lionberg, Daniel; Volckens, John
These measurement data were collected by participants using the Aerosol Mass and Optical Depth (AMOD) sampler during a pilot campaign for the Citizen-Enabled Aerosol Measurements for Satellites (CEAMS) network in Fall/Winter 2017 in northern Colorado. Data include multi-wavelength aerosol optical depth, filter mass and composition, and optical particle mass concentrations (for a subset of the files).
Open Access
Data for "The convection connection: how ocean feedbacks affect tropical mean moisture and MJO propagation."
(Colorado State University. Libraries, 2019) DeMott, Charlotte; Klingaman, Nicholas P.; Tseng, Wan-Ling; Burt, Melissa A.; Gao, Yingxia; Randall, David A.
Open Access
Data for Temporal and spatial variability of ammonia in urban and agricultural regions of northern Colorado, United States
(Colorado State University. Libraries, 2017) Li, Yi; Thompson, Tammy M.; Van Damme, Martin; Chen, Xi; Benedict, Katherine B.; Shao, Yixing; Day, Derek; Boris, Alexandra; Sullivan, Amy P.; Ham, Jay; Whitburn, Simon; Clarisse, Lieven; Coheur, Pierre-François; Collett, Jeffrey
Concentrated agricultural activities and animal feeding operations in the northeastern plains of Colorado represent an important source of atmospheric ammonia (NH3) that contributes to regional fine particle formation and to nitrogen deposition to sensitive ecosystems in Rocky Mountain National Park (RMNP) located ~ 80 km to the west. In order to better understand temporal and spatial differences in NH3 concentrations in this source region, weekly concentrations of NH3 were measured at 14 locations during the summers of 2010 to 2015 using Radiello passive NH3 samplers. Weekly (biweekly in 2015) average NH3 concentrations ranged from 2.66 μg/m3 to 42.7 μg/m3 with the highest concentrations near large concentrated animal feeding operations (CAFOs). The annual summertime mean NH3 concentrations were stable in this region from 2010 to 2015, providing a baseline against which concentration changes associated with future changes in regional NH3 emissions can be assessed. Vertical profiles of NH3 were also measured on the 300 m Boulder Atmospheric Observatory (BAO) tower throughout 2012. The highest NH3 concentration along the vertical profile was always observed at the 10 m height (annual average concentration of 4.63 μg/m3), decreasing toward the surface (4.35 μg/m3) and toward higher altitudes (1.93 μg/m3). Seasonal changes in the steepness of the vertical concentration gradient were observed, with the sharpest gradients in cooler seasons when thermal inversions restricted vertical mixing of surface-based emissions. The NH3 spatial distributions measured using the passive samplers are compared with NH3 columns retrieved by the Infrared Atmospheric Sounding Interferometer (IASI) satellite and concentrations simulated by the Comprehensive Air quality Model with extensions (CAMx), providing insight into the regional performance of each. The satellite comparison adds to a growing body of evidence that IASI column retrievals of NH3 provide very useful insight into regional variability in atmospheric NH3, in this case even in a region with strong local sources and sharp spatial gradients. The CAMx comparison indicates that the model does a reasonable job simulating NH3 concentrations near sources but tends to underpredict concentrations at locations farther downwind. Excess NH3 deposition by the model is hypothesized as a possible explanation for this trend.
Open Access
Data for the article The evolution of biomass-burning aerosol size distributions due to coagulation: dependence on fire and meteorological details and parameterization
(Colorado State University. Libraries, 2016) Pierce, Jeffrey; Sakomoto, Kimiko
This study calculated the evolution of aerosol size distributions in biomass burning plumes and is used the publication Sakamoto et al., 2016. In this repository we include the SAM-TOMAS input and output data that we used to build our emulator and simple fits. We also include the emulator code, which was also included in the supplementary material of our paper.

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