Version 4 is the current version of the data set. Older versions are no longer available and have been superseded by Version 4.These data are a part of MEaSUREs 2012 projects. The particular project, "Multi-Decadal Sulfur Dioxide Climatology from Satellite Instruments", is expected to produce SO2 Earth Science Data Record by means of combining measurements from backscatter Ultraviolet (BUV), thermal infrared (IR) and microwave (MLS) instruments on multiple satellites. The data represent best estimates of the volcanic and anthropogenic contribution to global atmospheric SO2 concentrations. Since SO2 is the major precursor of sulfate aerosol, which has climate and air quality impact, SO2 measurements will contribute to better understanding of the sulfate aerosol distributions and its atmospheric impact."The released data file is a long-term database of volcanic SO2 emission derived from ultraviolet satellite measurements from October 31, 1978, to present.Data are in a table format in simple ASCII format:Column Descriptions:Column 1 = Name of volcano.Column 2 = Latitude of volcano.Column 3 = Longitude of volcano.Column 4 = Altitude of volcano (km).Column 5 = Eruption year.Column 6 = Eruption month of year.Column 7 = Eruption day of month.Column 8 = Eruption style: exp = explosive, eff = effusive.Column 9 = Eruption volcanic explosivity index (nd = no data or undetermined).Column 10 = Observed plume altitude (km) where known.Column 11 = Estimated plume altitude (km) above vent: 10 km for explosive, 5 km for effusive.Column 12 = Measured SO2 mass in kilotons (= 1000 metric tons).

Version 4 is the current version of the data set. Older versions are no longer available and have been superseded by Version 4. These data are a part of MEaSUREs 2012 projects. The particular project, "Multi-Decadal Sulfur Dioxide Climatology from Satellite Instruments", is expected to produce SO2 Earth Science Data Record by means of combining measurements from backscatter Ultraviolet (BUV), thermal infrared (IR) and microwave (MLS) instruments on multiple satellites. The data represent best estimates of the volcanic and anthropogenic contribution to global atmospheric SO2 concentrations. Since SO2 is the major precursor of sulfate aerosol, which has climate and air quality impact, SO2 measurements will contribute to better understanding of the sulfate aerosol distributions and its atmospheric impact." The released data file is a long-term database of volcanic SO2 emission derived from ultraviolet satellite measurements from October 31, 1978, to present. Data are in a table format in simple ASCII format: Column Descriptions: Column 1 = Name of volcano. Column 2 = Latitude of volcano. Column 3 = Longitude of volcano. Column 4 = Altitude of volcano (km). Column 5 = Eruption year. Column 6 = Eruption month of year. Column 7 = Eruption day of month. Column 8 = Eruption style: exp = explosive, eff = effusive. Column 9 = Eruption volcanic explosivity index (nd = no data or undetermined). Column 10 = Observed plume altitude (km) where known. Column 11 = Estimated plume altitude (km) above vent: 10 km for explosive, 5 km for effusive. Column 12 = Measured SO2 mass in kilotons (= 1000 metric tons).

The NARSTO_SOS_SC_UPSTATE_PM25_COMPOSITION data were collected during July 2001 and January of 2002 to elucidate the seasonal variability of the aerosols. Samples were collected at a rural location in South Carolina, beginning and ending at midnight in order to associate each sampling event with a calendar day. In all, 40 samples per month were collected (including blanks).The purpose of the study was to determine experimentally the concentration and chemical composition of fine particulate matter (PM2.5, particles with a diameter less than 2.5 um) in South Carolina. The collection of PM2.5 samples on Teflon filters was carried out using a cyclone-based system. Ion chromatography analysis for anions and cations was performed, as well as x-ray fluorescence (XRF) analysis for crustal metals. PM2.5 samples on quartz filters were also collected in order to determine the organic and elemental carbon (EC/OC) particle concentration.The average concentration for PM2.5 during July of 2001 was 20.85 mg/m3. The major components of the aerosol were organic compounds (38.5%) and sulfates (34.7%). During January of 2002, the average concentration for PM2.5 was 9.4 mg/m3. Again, the major components of the aerosol were organic compounds (64.1%) and sulfates (21.9%).NARSTO (formerly North American Research Strategy for Tropospheric Ozone) is a public/private partnership, whose membership spans government, the utilities, industry, and academe throughout Mexico, the United States, and Canada. The primary mission is to coordinate and enhance policy-relevant scientific research and assessment of tropospheric pollution behavior; activities provide input for science-based decision-making and determination of workable, efficient, and effective strategies for local and regional air-pollution management. Data products from local, regional, and international monitoring and research programs are available.

SCAR_B_UWC131A data are Smoke/Sulfates, Clouds and Radiation Experiment in Brazil data from instruments on board the University of Washington C131A aircraft in Native format.Smoke/Sulfates, Clouds and Radiation - Brazil (SCAR-B) data include physical and chemical components of the Earth's surface, the atmosphere and the radiation field collected in Brazil with an emphasis in biomass burning.The objectives for the SCAR mission are: to advance our knowledge of how the physical, chemical and radiative processes in our atmosphere are affected by sulfate aerosol and smoke from biomass burning; to improve our expertise at remotely sensing smoke, water vapor, clouds, vegetation and fires; and to assess the effects of deforestation and biomass burning on tropical landscapes.From 17 August to 20 September 1995, the University of Washington's (UW) Cloud and Aerosol Research Group, with its Convair C-131A research aircraft, participated in an intensive field study of smoke emissions from various types of biomass burning over a large area of Brazil. This included 29 flights to collect measurements and photographs.

TL2SUMS_8 is the Tropospheric Emission Spectrometer (TES)/Aura Level 2 Atmospheric Temperatures Limb 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 contains 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, over which 3,200 retrievals were performed. 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 consists of observations along 16 consecutive orbits at the start of a two day cycle, over which 3,200 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 wa 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 is employed. Also, missing or bad retrievals were not reported. The organization of data within the Swath object was based on a superset of the Upper Atmosphere Research Satellite (UARS) pressure levels that was used to report concentrations of trace atmospheric gases. The reporting grid was the same pressure grid used for modeling. There were 67 reporting levels from 1211.53 hPa, which allowed for very high surface pressure conditions, to 0.1 hPa, about 65 km. In addition, the products reported values directly at the surface when possible or at the observed cloud top level. Thus in the Standard Product files each observation could potentially contain estimates for the concentration of a particular molecule at 67 different pressure levels within the atmosphere. However, for most retrieved profiles, the highest pressure levels were not observed due to a surface at lower pressure or cloud obscuration. For pressure levels corresponding to altitudes below the cloud top or surface, where measurements were not possible, a fill value was applied.To minimize the duplication of information between the individual species standard products, data fields common to each species (such as spacecraft coordinates, emissivity, and other data fields) have been collected into a separate standard product, termed the TES L2 Ancillary Data product (ESDT short name: TL2ANC). Users of this product should also obtain the Ancillary Data product.

SCAR_B_AERONET data are Smoke, Clouds and Radiation Brazil (SCARB) Aerosol Robotic Network (AERONET) data for aerosol characterization.Smoke/Sulfates, Clouds and Radiation - Brazil (SCAR-B) data include physical and chemical components of the Earth's surface, the atmosphere and the radiation field collected in Brazil with an emphasis in biomass burning.The objectives for the SCAR mission are: to advance our knowledge of how the physical, chemical and radiative processes in our atmosphere are affected by sulfate aerosol and smoke from biomass burning; to improve our expertise at remotely sensing smoke, water vapor, clouds, vegetation and fires; and to assess the effects of deforestation and biomass burning on tropical landscapes.AERONET (AErosol RObotic NETwork) is an optical ground based aerosol monitoring network and data archive supported by NASA's Earth Observing System and expanded by federation with many non-NASA institutions. The network hardware consists of identical automatic sun-sky scanning spectral radiometers owned by national agencies and universities. Data from this collaboration provides globally distributed near real time observations of aerosol spectral optical depths, aerosol size distributions, and precipitable water in diverse aerosol regimes. The data undergo preliminary processing (real time data), reprocessing (final calibration ~6 mo. after data collection), quality assurance, archiving and distribution from NASA's Goddard Space Flight Center master archive and several identical data bases maintained globally. The data provide algorithm validation of satellite aerosol retrievals and as well as characterization of aerosol properties that are unavailable from satellite sensors.

SCAR_A_ER2_MAS data are Sulfates, Clouds and Radiation America (SCARA) NASA ER2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS) Data in Hierarchical Data Format (HDF).Smoke/Sulfates, Clouds and Radiation - America (SCAR-A) data include physical and chemical components of the Earth's surface, the atmosphere and the radiation field collected in the eastern part of the United States with an emphasis in air pollution.The primary objective of the SCAR-A experiment was to help scientists characterize the the relationship between sulfate particles and clouds' reflective properties. Sulfate aerosols are believed to provide condensation nuclei, resulting in smaller, more numerous droplets within a cloud. SCAR-A was the first in a series of experiments. It was was followed by the SCAR-C experiment conducted over California in 1994. A third experiment, SCAR-B was conducted in Brazil during August and September 1995. The MODIS Airbourne Simulator (MAS) is a modified Daedalus Wildfire scanning spectrometer which flies on a NASA ER-2 and provides spectral information similar to that provided by the Moderate Resolution Imaging Spectroradiometer (MODIS), launched on Terra (EOS AM-1) in 1999 and Aqua (EOS PM-1) in 2002. The MAS spectrometer acquires high spatial resolution imagery in the wavelength range of 0.55 to 14.3 microns. A total of 50 spectral bands are available in this range, and the digitizer can be configured to collect data from any 12 of these bands. The digitizer was configured with four 10-bit channels and seven 8-bit channels. The MAS spectrometer was mated to a scanner subassembly which collected image data with an IFOV of 2.5 mrad, giving a ground resolution of 50 meters from 20000 meters altitude, and a cross track scan width of 85.92 degrees. The data granules were written using the self documenting file storage format provided through the netCDF interface routines included in the HDF libraries.

Version 3 is the current version of the data set. Older versions will no longer be available and have been superseded by Version 3.The goal of this data set is to create and archive a Level 2 SO2 Earth Science Data Record (ESDR) from backscatter Ultraviolet (BUV) measurements from Total Ozone Mapping Spectrometer (TOMS) flown on NASA's Nimbus - 7 satellite in 1978-1993. We apply TOMS ozone team calibration techniques and consistent MEaSUREs SO2 (MS_SO2) algorithm, to obtain the best measurement-based ESDR of volcanic and anthropogenic SO2 masses and emissions. As part of the NASA's Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, the Goddard Earth Science (GES) Data and Information Data Center (DISC) has released a new SO2 Earth System Data Record (ESDR), TOMSN7SO2, re-processed using new 4 UV wavelength bands MS_SO2 algorithm that spans the full Nimbus 7 data period. TOMSN7SO2 is a Level 2 orbital swath product, which will be used to study the fifteen-year SO2 record from the Nimbus-7 TOMS and to expand the historical database of known volcanic eruptions. Sulfur Dioxide (SO2) is a short-lived gas primarily produced by volcanoes, power plants, refineries, metal smelting and burning of fossil fuels. Where SO2 remains near the Earth s surface, it is toxic, causes acid rain, and degrades air quality. Where SO2 is lofted into the free troposphere, it forms aerosols that can alter cloud reflectivity and precipitation. In the stratosphere, volcanic SO2 forms sulfate aerosols that can result in climate change.