The Advanced Vertical Atmospheric Profiling System (AVAPS) IMPACTS dataset consists of vertical atmospheric profile measurements collected by the Advanced Vertical Atmospheric Profiling System (AVAPS) dropsondes released from the NASA P-3 aircraft during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign. IMPACTS was a three-year sequence of winter season deployments conducted to study snowstorms over the U.S Atlantic Coast (2020-2023). The campaign aimed to (1) Provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution; (2) Examine how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands; and (3) Improve snowfall remote sensing interpretation and modeling to significantly advance prediction capabilities. AVAPS uses a Global Positioning System (GPS) dropsonde to measure atmospheric state parameters (temperature, humidity, wind speed/direction, pressure) and location in 3-dimensional space during the dropsonde’s descent. The AVAPS dataset files are available from January 12, 2020, through February 28, 2023, in ASCII-ict format.

The P-3 Meteorological and Navigation Data IMPACTS dataset is a subset of airborne measurements that include GPS positioning and trajectory data, aircraft orientation, and atmospheric state measurements of temperature, pressure, water vapor, and horizontal winds. These measurements were taken from the NASA P-3 aircraft during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) campaign. Funded by NASA’s Earth Venture program, IMPACTS is the first comprehensive study of East Coast snowstorms in 30 years. The campaign aimed to (1) Provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution; (2) Examine how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands; and (3) Improve snowfall remote sensing interpretation and modeling to significantly advance prediction capabilities. Data are available in ASCII-ict format from January 12, 2020 through February 25, 2022.

The Hurricane and Severe Storm Sentinel (HS3) Global Hawk Advanced Vertical Atmospheric Profiling System (AVAPS) Dropsonde System dataset was collected by the Advanced Vertical Atmospheric Profiling System (AVAPS), built by the National Center for Atmospheric Research (NCAR), which served as the dropsonde system for the Global Hawk aircraft during the HS3 campaign. Goals for HS3 included: assessing the relative roles of large-scale environment and storm-scale internal processes; and addressing the controversial role of the Saharan Air Layer (SAL) in tropical storm formation and intensification as well as the role of deep convection in the inner-core region of storms. AVAPS dropsondes provide in-situ, high-vertical resolution measurements of atmospheric variables including pressure, temperature, humidity, geographic location, and winds, providing a vertical profile of the atmospheric conditions. The raw instrument measurement precision is as follows: pressure +-1.0 hPa, temperature +-0.2 degrees C, wind +-1 ms-1, and humidity +-7 percent. The measured information was transmitted via Iridium or Ku-Band satellite to the ground station where the Global Telecommunications System (GTS) performed additional processing for research and operational purposes.

The Alpha Jet Atmospheric eXperiment (AJAX) is a partnership between NASA's Ames Research Center and H211, L.L.C., facilitating routine in-situ measurements over California, Nevada, and the coastal Pacific in support of satellite validation. The standard payload complement includes rigorously-calibrated ozone (O3), formaldehyde (HCHO), carbon dioxide (CO2), and methane (CH4) mixing ratios, as well as meteorological data including 3-D winds. Multiple vertical profiles (to ~8.5 km) can be accomplished in each 2-hr flight. The AJAX project has been collecting trace gas data on a regular basis in all seasons for over a decade, helping to assess satellite sensors' health and calibration over significant portions of their lifetimes, and complementing surface and tower-based observations collected elsewhere in the region.AJAX supports NASA's Orbiting Carbon Observatory (OCO-2/3) and Japan's Greenhouse Gases Observing Satellite (GOSAT) and GOSAT-2, and collaborates with many other research organizations (e.g. California Air Resources Board (CARB), NOAA, United States Forest Service (USFS), Environmental Protection Agency (EPA)). AJAX celebrated its 200th science flight in 2016, and previous studies have investigated topics as varied as stratospheric-to-tropospheric transport, forest fire plumes, atmospheric river events, long-range transport of pollution from Asia to the western US, urban outflow, and emissions from gas leaks, oil fields, and dairies.

The NCAR Particle Probes IMPACTS dataset consists of data collected from six instruments on the NASA P-3 aircraft, the SPEC Hawkeye Cloud Particle Imager (CPI), the Hawkeye Fast Cloud Droplet Probe (FastCDP), the Hawkeye Two-Dimensional Stereo Probe (Hawkeye2D-S), the SPEC Two-Dimensional Stereo probe (2D-S), and two SPEC High Volume Precipitation Spectrometers (HVPS3). The 2D-S and HVPS3 are two-dimensional optical array probes which record images of particles that travel through their sampling area. The recorded images are then analyzed to produce particle size distributions from 20 microns to 3 centimeters in diameter. The FastCDP is a forward scattering instrument designed to measure the size and concentration of cloud droplets between 2 and 50 microns in diameter. The CPI is a high-resolution imager with a 256-level color depth. No particle concentration estimates have been attempted with the CPI. These data were collected during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign, a three-year sequence of winter season deployments conducted to study snowstorms over the U.S Atlantic coast. IMPACTS aimed to (1) Provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution; (2) Examine how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands; and (3) Improve snowfall remote sensing interpretation and modeling to significantly advance prediction capabilities. Data files are available in netCDF-4 format, as well as browse imagery available in PNG format, from January 18, 2020 through February 26, 2020, and January 14, 2022 through February 25, 2022.

SOLVE1_AircraftRemoteSensing_DC8_LASE_Data is the remotely sensed trace gas data for the DC-8 aircraft collected during the SAGE III Ozone Loss and Validation Experiment (SOLVE) by the Lidar Atmospheric Sensing Experiment (LASE) instrument. Data collection for this product is complete.The SOLVE campaign was a NASA multi-program effort of the Upper Atmosphere Research Program (UARP), Atmospheric Effects of Aviation Project (AEAP), Atmospheric Chemistry Modeling and Analysis Program (ACMAP) and Earth Observing System (EOS) of NASA’s Earth Science Enterprise (ESE). SOLVE’s primary objective was for calibrating and validating the Stratospheric Aerosol and Gas Experiment (SAGE) III satellite measurements, while examining the processes that controlled ozone levels at a mid- to high-latitude range. The major goal of SAGE III was to quantitatively assess ozone loss at high latitudes. SOLVE was a two-phase experiment, the first phase, SOLVE, occurred during the fall of 1999 through the spring of 2000. The second phase, SOLVE II, occurred during the winter of 2003.SOLVE took place in the Arctic high-latitude region during the winter. The polar ozone depletion processes cause by human-produced chlorine and bromine are most active in mid-to-late winter and early spring in the high Arctic. In order to conduct this validation experiment, NASA deployed the NASA ER-2 aircraft and NASA DC-8 aircraft. The ER-2 measured a variety of atmospheric data, including ozone (O3), H2O, CO2, ClONO2, HCl, ClO/BrO, and Cl2O2. The DC-8 aircraft measured ozone, ClO/BrO, and aerosol, among other atmospheric data. SOLVE also utilized balloon platforms, ground-based instruments, and collaborations with the German Aerospace Center’s (DLR) FALCON aircraft equipped with the OLEX Lidar to achieve the mission objectives. Overall, the campaign had 28 flights, with SOLVE featuring 17 total flights among the different aircrafts and SOLVE II featuring 11 flights.

The Autonomous Parsivel Unit (APU) IMPACTS data were collected in support of the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) campaign. The IMPACTS field campaign addressed providing observations critical to understanding the mechanisms of snowband formation, organization, and evolution, examining how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands, and improving snowfall remote sensing interpretation and modeling to significantly advance prediction capabilities. This dataset consists of precipitation data including precipitation amount, precipitation rate, reflectivity in Rayleigh regime, liquid water content, drop diameter, and drop concentration. Data are available in ASCII format from January 15, 2020 through February 29, 2020.

The Alpha Jet Atmospheric eXperiment (AJAX) is a partnership between NASA's Ames Research Center and H211, L.L.C., facilitating routine in-situ measurements over California, Nevada, and the coastal Pacific in support of satellite validation. The standard payload complement includes rigorously-calibrated ozone (O3), formaldehyde (HCHO), carbon dioxide (CO2), and methane (CH4) mixing ratios, as well as meteorological data including 3-D winds. Multiple vertical profiles (to ~8.5 km) can be accomplished in each 2-hr flight. The AJAX project has been collecting trace gas data on a regular basis in all seasons for over a decade, helping to assess satellite sensors' health and calibration over significant portions of their lifetimes, and complementing surface and tower-based observations collected elsewhere in the region. AJAX supports NASA's Orbiting Carbon Observatory (OCO-2/3) and Japan's Greenhouse Gases Observing Satellite (GOSAT) and GOSAT-2, and collaborates with many other research organizations (e.g. California Air Resources Board (CARB), NOAA, United States Forest Service (USFS), Environmental Protection Agency (EPA)). AJAX celebrated its 200th science flight in 2016, and previous studies have investigated topics as varied as stratospheric-to-tropospheric transport, forest fire plumes, atmospheric river events, long-range transport of pollution from Asia to the western US, urban outflow, and emissions from gas leaks, oil fields, and dairies.

PEM-Tropics-B_AircraftRemoteSensing_DC8_LASE_Data is the remotely sensed Lidar Atmospheric Sensing Experiment (LASE) data collected onboard the DC-8 aircraft during the Pacific Exploratory Mission (PEM) Tropics B suborbital campaign. Data collection for this product is complete.From 1983-2001, NASA conducted a collection of field campaigns as part of the Global Tropospheric Experiment (GTE). Among those was PEM, which intended to improve the scientific understanding of human influence on tropospheric chemistry. Part of the PEM field campaigns were focused on the tropical Pacific region (PEM-Tropics) which was recognized as a “very large chemical vessel.” The overarching science objective was to assess the anthropogenic impact on tropospheric oxidizing power. A secondary objective was to investigate the impact of atmospheric sulfur chemistry, including oxidation of marine biogenic emission of dimethyl sulfide (DMS) on aerosol loading and radiative effect, which is of critical importance in the assessment of global climate change. The PEM-Tropics mission was conducted in two phases to contrast the influence of biomass burning in the dry season and the “relatively clean” wet season. The first, PEM-Tropics A, was carried out during the end of the dry season (August-September 1996), and the second, PEM-Topics B, was conducted during the wet season (March-April 1999). To accomplish its objectives, PEM-Tropics enlisted the NASA DC-8 and P-3B aircrafts to carry out longitudinal and latitudinal surveys at various altitudes as well as vertical profile sampling across the Pacific basin. Both aircrafts were equipped with in-situ instruments measuring hydroperoxyl radicals (HOx), ozone (O3), photochemical precursors (including, reactive nitrogen species and non-methane hydrocarbon species), and intermediate products (e.g., hydrogen peroxide (H2O2), formaldehyde (CH2O), and acetic acid (CH3OOH). The P3-B in-situ instrument payload also included a direct measurement of hydroxyl (OH) for both missions, while the OH and hydroperoxyl radical (HO2) measurements were added to DC-8 aircraft for PEM-Tropics B. Taking advantage of its excellent low altitude capability, the P-3B was instrumented with a comprehensive sulfur measurement package and conducted pseudo-Lagragian sampling for evaluating DMS oxidation chemistry, including measurements of DMS, sulfur dioxide (SO2), sulfuric acid (H2SO4), and methylsulfonic acid (MSA) as well as the first airborne measurement of dimethyl sulfoxide (DMSO) during PEM-Tropics B. More importantly, it was the first time that DMS (the source), OH and O3 (primary oxidants), and products (DMSO, MSA, H2SO4, SO2) were measured simultaneously aboard an aircraft in the tropical pacific. These observations, specifically DMSO, presented a substantial challenge to the DMS oxidation kinetics to this day. The DC-8 aircraft was equipped with the Differential Absoprtion Lidar (DIAL) during PEM-Tropics A, and the differential absorption lidars DIAL and LASE during PEM-Tropics B. These lidars provided real-time information for fine tuning the flight tracks to capture sampling opportunities. The lidar data products themselves provide valuable information of vertical profiles of ozone as well as aerosol and water vapor in tropical Pacific Furthermore, both aircrafts were fitted with instruments for aerosol composition and microphysical property measurements. Detailed description related to the motivation, implementation, and instrument payloads are available in the PEM-Tropics A overview paper and the PEM-Tropics B overview paper. Most of the publications based on PEM-Tropics A and B observations are available in the Journal of Geophysical Research special issues: Pacific Exploratory Mission-Tropics A and NASA Global Tropospheric Experiment Pacific Exploratory Mission in the Tropics Phase B: Measurement and Analyses (PEM-Tropics B), while other publications such as Nowak et al. (2001) were published prior to the special issues.

The Automated Surface Observing Systems (ASOS) IMPACTS dataset consists of a variety of ground-based observations during the Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS) field campaign. IMPACTS was a three-year sequence of winter season deployments conducted to study snowstorms over the U.S Atlantic coast. IMPACTS aimed to (1) Provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution; (2) Examine how the microphysical characteristics and likely growth mechanisms of snow particles vary across snowbands; and (3) Improve snowfall remote sensing interpretation and modeling to significantly advance prediction capabilities. This ASOS dataset consists of 176 stations within the IMPACTS domain. Each station provides observations of surface temperature, dew point, precipitation, wind direction, wind speed, wind gust, sea level pressure, and the observed weather code. The ASOS data are available from December 29, 2019 through February 29, 2020 in netCDF-4 format.