This dataset, collected with the Unmanned Aircraft Systems (UAS) Chromatograph for Atmospheric Trace Species (UCATS), provides atmospheric concentrations of nitrous oxide (N2O), sulfur hexafluoride (SF6), methane (CH4), hydrogen (H2), carbon monoxide (CO), water vapor (H2O), and ozone (O3). The UCATS system is three different instruments in one enclosure: a two-channel chromatograph with electron capture detectors (one measures N2O and SF6, the other measures CH4, H2 and CO), a tunable diode laser instrument for H2O, and a dual-beam O3 photometer.

This dataset provides O2/N2, CO2, Ar/N2, and stable isotope ratios of CO2 measured in flasks collected by the Medusa Whole Air Sampler during airborne campaigns conducted by NASA's Atmospheric Tomography (ATom) mission. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for a systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Flights occurred in each of 4 seasons from 2016 to 2018. Medusa collected 32 cryogenically dried, flow, and pressure-controlled samples per flight. The samples are collected by an automated sampler into 1.5 L glass flasks that integrate over 25 seconds. Medusa provides discretely-sampled comparisons for onboard in situ O2/N2 ratio and CO2 measurements and unique measurements of Ar/N2 and 13C, 14C, and 18O isotopologues of CO2. Medusa flasks are analyzed on a sector-magnet mass spectrometer and a LiCor non-dispersive infrared CO2 analyzer by the Scripps O2 Program at Scripps Institution of Oceanography.

The Halocarbons and other Atmospheric Trace Species (HATS) group aims to quantify the distributions and magnitudes of sources and sinks for atmospheric nitrous oxide and halogen containing compounds. They utilize numerous types of platforms, including ground-based stations, towers, ships, aircraft, and balloons to accomplish their mission. HATS also measures chlorofluorocarbons (CFCs) at its various measurement sites. CFCs are nontoxic, nonflammable chemicals that contains atoms of carbon, chlorine, and fluorine. They are classified as halocarbons which are compounds that contain carbon and halogen atoms. CFCs were used as solvents, refrigerants, and aerosol sprays. While inert in the lower atmosphere, CFCs decompose in the upper atmosphere (stratosphere) with some of the released chlorine becoming active in destroying ozone in the stratosphere. Over time this lead to the creation of the "Ozone Hole" over the Antarctic. Monitoring the amounts of CFCs and other trace gases is important to tracking the growth or recovery of the Ozone Hole. The Chromatograph for Atmospheric Trace Species (CATS) instruments have been in operation at the NOAA baseline observatories (Barrow, AK, Mauna Loa, HI, American Samoa, and South Pole, Antarctica) since 1999. The CATS instrument measure nitrous oxide (N2O), sulfur hexafluoride (SF6), chlorofluorocarbons (CFC-12 (CCl2F2), CFC-11 (CCl3F), and CFC-113 (CCl2F-CClF2)), Halon-1211 (CBrClF2), methyl chloroform (CH3CCl3), and carbon tetrachloride (CCl4). The CATS gas chromatographs are custom built instruments that contain separation columns, flow controllers, an air selection valve, and an electron capture detector; all used for making measurements. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.

TL2CH4NS_8 is the Tropospheric Emission Spectrometer (TES)/Aura Level 2 Methane Nadir Special Observation Version 8 data product. TES was an instrument aboard NASA's Aura satellite and was launched from California on July 15, 2004. Data collection for TES is complete. TES Level 2 data contain retrieved species (or temperature) profiles at the observation targets and the estimated errors. The geolocation, quality, and other data (e.g., surface characteristics for nadir observations) were also provided. L2 modeled spectra were evaluated using radiative transfer modeling algorithms. The process, referred to as retrieval, compared observed spectra to the modeled spectra and iteratively updated the atmospheric parameters. L2 standard product files included information for one molecular species (or temperature) for an entire global survey or special observation run. A global survey consisted of a maximum of 16 consecutive orbits.Nadir observations, which point directly to the surface of the Earth, are different from limb observations, which are pointed at various off-nadir angles into the atmosphere. Nadir and limb observations were added to separate L2 files, and a single ancillary file was composed of data that are common to both nadir and limb files. A Nadir sequence within the TES Global Survey was a fixed number of observations within an orbit for a Global Survey. Prior to April 24, 2005, it consisted of two low resolution scans over the same ground locations. After April 24, 2005, Global Survey data consisted of three low resolution scans. The Nadir standard product consists of four files, where each file is composed of the Global Survey Nadir observations from one of four focal planes for a single orbit, i.e. 72 orbit sequences. The Global Survey Nadir observations only used a single set of filter mix. A Global Survey consisted of observations along 16 consecutive orbits at the start of a two day cycle, over which 4,608 retrievals were performed. Each observation was the input for retrievals of species Volume Mixing Ratios (VMRs), temperature profiles, surface temperature, and other data parameters with associated pressure levels, precision, total error, vertical resolution, total column density, and other diagnostic quantities. Each TES Level 2 standard product reported information in a swath format conforming to the HDF-EOS Aura File Format Guidelines. Each Swath object was bounded by the number of observations in a global survey and a predefined set of pressure levels, representing slices through the atmosphere. Each standard product could have had a variable number of observations depending upon the Global Survey configuration and whether averaging was employed. Also, missing or bad retrievals were not reported. Further, observations were occasionally scheduled on non-global survey days. In general they were measurements made for validation purposes or with highly focused science objectives. Those non-global survey measurements were referred to as “special observations.”A Limb sequence within the TES Global Survey was three high-resolution scans over the same limb locations. The Limb standard product consists of four files, where each file is composed of the Global Survey Limb observations from one of four focal planes for a single orbit, i.e. 72 orbit sequences. The Global Survey Limb observations used a repeating sequence of filter wheel positions. Special Observations could only be scheduled during the 9 or 10 orbit gaps in the Global Surveys, and were conducted in any of three basic modes: stare, transect, step-and-stare. The mode used depended on the science requirement. Each limb observation Limb 1, Limb 2 and Limb 3, were processed independently. Thus, each limb standard product consisted of three sets where each set consisted of 1,152 observations. For TES, the swath object represented one of these sets. Thus, each limb standard product consisted of three swath objects, one for each observation, Limb 1, Limb 2,

This dataset, collected with the Unmanned Aircraft Systems (UAS) Chromatograph for Atmospheric Trace Species (UCATS), provides atmospheric concentrations of nitrous oxide (N2O), sulfur hexafluoride (SF6), methane (CH4), hydrogen (H2), carbon monoxide (CO), water vapor (H2O), and ozone (O3). The UCATS system is three different instruments in one enclosure: a two-channel chromatograph with electron capture detectors (one measures N2O and SF6, the other measures CH4, H2 and CO), a tunable diode laser instrument for H2O, and a dual-beam O3 photometer.

The Halocarbons and other Atmospheric Trace Species (HATS) group aims to quantify the atmospheric burden, and the distributions and magnitudes of sources and sinks for nitrous oxide and other halogen containing compounds. They utilize numerous types of platforms, including ground-based stations, towers, ships, aircraft, and balloons to accomplish their mission. HATS measures chlorofluorocarbons (CFCs) at measurement sites spanning the globe. CFCs are non-toxic, non-flammable chemicals that contain carbon, chlorine, and fluorine atoms. CFCs were used as solvents, refrigerants, and aerosol sprays. While inert in the troposphere, they decompose in the stratosphere to release chlorine for destructive reactions with ozone. This process eventually led to the creation of the "Ozone Hole" over the Antarctic. Monitoring the amounts of CFCs and other trace gases is important, both for tracking the growth and recovery of the Ozone Hole, and because many upward trending trace gases are potent and durable greenhouse gases. Original in-situ sampling electron capture gas chromatographs ("RITS"): The Radiatively Important Trace Species (RITS) program consisted of five stand-alone systems that were used to make in-situ measurements at Barrow, AK (BRW), Mauna Loa, HI (MLO), American Samoa (SMO), South Pole, Antarctica (SPO), and Niwot Ridge, CO (NWR) from 1983 until 2001 when the last of the systems was retired. The RITS systems were replaced by the next-generation CATS systems that have remained operational since then. The RITS systems measured nitrous oxide (N2O), the chlorofluorocarbons CFC-12 (CCl2F2), CFC-11 (CCl3F), and CFC-113 (CCl2F-CClF2, although quality measurements of this gas have been nullified by the lack of stable references during the RITS period), methyl chloroform (CH3CCl3), and carbon tetrachloride (CCl4) once per hour. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.

FIREXAQ_TraceGas_AircraftRemoteSensing_DC8_Data are remotely sensed trace gas measurements conducted onboard the DC8 aircraft during FIREX-AQ. This product features data collected by the DOAS instrument. Data collection for this product is complete.Completed during summer 2019, FIREX-AQ utilized a combination of instrumented airplanes, satellites, and ground-based instrumentation. Detailed fire plume sampling was carried out by the NASA DC-8 aircraft, which had a comprehensive instrument payload capable of measuring over 200 trace gas species, as well as aerosol microphysical, optical, and chemical properties. The DC-8 aircraft completed 23 science flights, including 15 flights from Boise, Idaho and 8 flights from Salina, Kansas. NASA’s ER-2 completed 11 flights, partially in support of the FIREX-AQ effort. The ER-2 payload was made up of 8 satellite analog instruments and provided critical fire information, including fire temperature, fire plume heights, and vegetation/soil albedo information. NOAA provided the NOAA-CHEM Twin Otter and the NOAA-MET Twin Otter aircraft to measure chemical processing in the lofted plumes of Western wildfires. The NOAA-CHEM Twin Otter focused on nighttime plume chemistry, from which data is archived at the NASA Atmospheric Science Data Center (ASDC). The NOAA-MET Twin Otter collected measurements of air movements at fire boundaries with the goal of understanding the local weather impacts of fires and the movement patterns of fires. NOAA-MET Twin Otter data will be archived at the ASDC in the future. Additionally, a ground-based station in McCall, Idaho and several mobile laboratories provided in-situ measurements of aerosol microphysical and optical properties, aerosol chemical compositions, and trace gas species. The Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) campaign was a NOAA/NASA interagency intensive study of North American fires to gain an understanding on the integrated impact of the fire emissions on the tropospheric chemistry and composition and to assess the satellite’s capability for detecting fires and estimating fire emissions. The overarching goal of FIREX-AQ was to provide measurements of trace gas and aerosol emissions for wildfires and prescribed fires in great detail, relate them to fuel and fire conditions at the point of emission, characterize the conditions relating to plume rise, and follow plumes downwind to understand chemical transformation and air quality impacts.

ATTREX-Aircraft_insitu_TraceGas_Measurements are in-situ trace gas measurements collected onboard the Global Hawk Uninhabited Aerial System (UAS) during the Airborne Tropical TRopopause EXperiment (ATTREX) campaign. This collection consists of in-situ trace gas measurements collected by the Diode Laser Hygrometer (DLH), UCATS Gas Chromatograph, Advanced Whole Air Sampler (AWAS), Harvard University Picarro Cavity Ringdown Spectrometer, 2 channel internal path Tunable-Diode Laser (TDL) absorption spectrometer, and Dual-channel Ultraviolet (UV) absorption spectrometer for O3 measurements during the 2011 and 2013 deployments over California, and 2014 deployment over Guam. Data collection is complete.Even though it is typically found in low concentrations, stratospheric water vapor has large impacts on the Earth’s climate and energy budget. Studies have suggested that even relatively small changes in stratospheric humidity may have significant climate impacts and future changes in stratospheric humidity and ozone concentration in response to a changing climate are significant climate feedbacks. Tropospheric water vapor climate feedback is typically well represented in global models. However, predictions of future changes in stratospheric humidity are highly uncertain due to gaps in our understanding of physical processes occurring in the region of the atmosphere that controls the composition of the stratosphere, the Tropical Tropopause Layer (TTL, ~13-18 km). The ability to predict future changes in stratospheric ozone are also limited due to uncertainties in the chemical composition of the TTL. In order to address these uncertainties, the Airborne Tropical Tropopause Experiment (ATTREX) was completed. Instruments during ATTREX provided measurements to trace the movement of reactive halogen-containing compounds and other important chemical species, the size and shape of cirrus cloud particles, water vapor, and winds in three dimensions through the TTL. Bromine-containing gases were measured to improve understanding of stratospheric ozone. ATTREX consisted of four NASA Global Hawk Uninhabited Aerial System (UAS) campaigns deployed from NASA’s Armstrong Flight Research Center (formally Dryden Flight Research Center). Campaigns were deployed over Edwards, CA, Guam, Hawaii, and Darwin, Australia in Boreal summer, winter, fall, and summer, respectively.