This dataset provides Level 1 (L1) remotely sensed differential absorption optical depth (DAOD) measurements made through the Multi-Functional Fiber Laser Lidar (MFLL; Harris Corporation) during airborne campaigns in Summer 2016, Winter 2017, Fall 2017, and Spring 2018 conducted over central and eastern regions of the United States for the Atmospheric Carbon and Transport (ACT-America) project. DAOD were measured at 0.1 second frequency during flights of the C-130 Hercules aircraft at altitudes up to 8 km with MFLL. The MFLL is a set of Continuous-Wave (CW) lidar instruments consisting of an intensity modulated multi-frequency single-beam synchronous-detection Laser Absorption Spectrometer (LAS) operating at 1571 nm for measuring the column amount of CO2 number density and range between the aircraft and the surface or to cloud tops, and surface reflectance and a Pseudo-random Noise (PN) altimeter at 1596 nm for measuring the path length from the aircraft to the scattering surface and/or cloud tops. The MFLL was onboard all ACT-America seasonal campaigns, except Summer 2019. Complete aircraft flight information, interpolated to the 0.1 second column CO2 reporting frequency, are included, but not limited to, latitude, longitude, altitude, and attitude. Data users should note that a Level 2 (L2) MFLL data product is available (related dataset) that contains all data variables (plus the column-average CO2) included in this L1 MFLL data product but has undergone additional processing and calibrations and is recommended for most use cases.

This dataset reports continuous atmospheric measurements of CO2 from two receptor sites and three boundary sites in and around Boston, Massachusetts, USA, that were combined with high-resolution CO2 emissions estimates and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to estimate regional CO2 emissions from September 2013 to December 2014. The HYSPLIT model followed an ensemble of 1,000 particles released at the urban CO2 measurement sites backward in time based on wind fields and turbulence from the North American Mesoscale Forecast System (NAM) at 12-km resolution to the boundary CO2 measurement sites to derive footprint values and CO2 enhancements expected from the prior emissions based on the Anthropogenic Carbon Emissions System (ACES) inventory and the urban-Vegetation Photosynthesis Respiration Model (urbanVPRM). This dataset contains three sets of data products: (1) observed hourly mean CO2 observations for two urban receptor sites in Boston, MA (Boston University (BU) and Copley Square (COP)), (2) observed hourly mean CO2 and calculated vertical profiles (50 - 5000 m) for three boundary sites around Boston including Harvard Forest at Petersham, MA (HF), Canaan, NH (CA), and Martha's Vineyard, MA (MVY), and modeled mean boundary CO2 concentrations for particles released from BU and COP, and (3) particle trajectory files including footprint values and CO2 enhancements above boundary CO2 concentrations from the HYSPLIT model.

This dataset provides Level 1 (L1) remotely sensed differential absorption optical depth (DAOD) measurements made through the Multi-Functional Fiber Laser Lidar (MFLL; Harris Corporation) during airborne campaigns in Summer 2016, Winter 2017, Fall 2017, and Spring 2018 conducted over central and eastern regions of the United States for the Atmospheric Carbon and Transport (ACT-America) project. DAOD were measured at 0.1 second frequency during flights of the C-130 Hercules aircraft at altitudes up to 8 km with MFLL. The MFLL is a set of Continuous-Wave (CW) lidar instruments consisting of an intensity modulated multi-frequency single-beam synchronous-detection Laser Absorption Spectrometer (LAS) operating at 1571 nm for measuring the column amount of CO2 number density and range between the aircraft and the surface or to cloud tops, and surface reflectance and a Pseudo-random Noise (PN) altimeter at 1596 nm for measuring the path length from the aircraft to the scattering surface and/or cloud tops. The MFLL was onboard all ACT-America seasonal campaigns, except Summer 2019. Complete aircraft flight information, interpolated to the 0.1 second column CO2 reporting frequency, are included, but not limited to, latitude, longitude, altitude, and attitude. Data users should note that a Level 2 (L2) MFLL data product is available (related dataset) that contains all data variables (plus the column-average CO2) included in this L1 MFLL data product but has undergone additional processing and calibrations and is recommended for most use cases.

The Global Greenhouse Gas Reference Network for the Carbon Cycle and Greenhouse Gases (CCGG) Group is part of NOAA'S Earth System Research Laboratory (ESRL) in Boulder, CO. The Reference Network measures the atmospheric distribution and trends of the three main long-term drivers of climate change, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as carbon monoxide (CO) which is an important indicator of air pollution. The Reference Network measurement program includes continuous in-situ measurements at 4 baseline observatories, also known as global background sites, and 8 tall towers, as well as flask-air samples collected by volunteers at over 50 additional sites, also known as regional background sites, and from small aircraft. The air samples are returned to ESRL for analysis where measurements of about 55 trace gases are done. NOAA's Global Greenhouse Gas Reference Network maintains the World Meteorological Organization international calibration scales for CO2, CH4, CO, N2O, and SF6 in air. The measurements of the Global Greenhouse Gas Reference Network serve as a comparison with measurements made by many other international laboratories, and with regional studies. They are widely used in studies inferring space-time patterns of emissions and removals of greenhouse gases that are optimally consistent with the atmospheric observations. They serve as an early warning for climate "surprises". The measurements are also helpful for the ongoing evaluation of remote sensing technologies. Tall Tower Measurements: ESRL's Global Monitoring Division (GMD) began making measurements from tall towers in the 1990s in order to extend long-term carbon-cycle gas monitoring to continental areas. Existing television, radio and cell phone towers are utilized as sampling platforms for continuous in-situ sampling of CO2 and other atmospheric trace gases, including carbon monoxide (CO) in the continental boundary layer. The measured data are baseline levels, trends, and causes of variability of atmospheric gases that have the potential to affect global climate. The tall tower sites are part of the North American Carbon Program and are a primary data source for ESRL's Carbon Tracker CO2 data assimilation system. The historic data set is from 8 tall towers. The ongoing data set is contingent upon the observation sites that are still in use going forward. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.

The data is for the companion paper: ZH Levine et al., The detection of carbon dioxide leaks using quasi-tomographic laser absorption spectroscopy, Atmospheric Measurement Techniques, in press (to appear 2016). The data include measurements carbon dioxide in the atmosphere in a field in Ft. Wayne, Indiana as well as simulations of such measurements.

The data is for the companion paper: ZH Levine et al., The detection of carbon dioxide leaks using quasi-tomographic laser absorption spectroscopy, Atmospheric Measurement Techniques, in press (to appear 2016). The data include measurements carbon dioxide in the atmosphere in a field in Ft. Wayne, Indiana as well as simulations of such measurements.

CAL_LID_L2_333mMLay-Standard-V4-20 is the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) Lidar Level 2 1/3 km Merged Layer, Version 4-20 data product. Data for this product was collected using the CALIPSO Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument. Data collection for this product is ongoing. CALIPSO was launched on April 28, 2006 to study the impact of clouds and aerosols on the Earth's radiation budget and climate. It flies in the international A-Train constellation for coincident Earth observations. The CALIPSO satellite comprises three instruments, CALIOP, Imaging Infrared Radiometer (IIR), and Wide Field Camera (WFC). CALIPSO is a joint satellite mission between NASA and the French Agency, CNES.

CAL_LID_L2_05kmALay-Standard-V4-21 is the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Lidar Level 2 5 km Aerosol Layer Data, Version 4-21 data product. This data product was collected using the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) instrument. The version of this product was changed from 4-20 to 4-21 to account for a change in the operating system of the CALIPSO production cluster. Data collection for this product is ongoing. Within the Lidar Aerosol Layer Product there are two general classes of data:- Column Properties (including position data and viewing geometry), and Layer Properties, the lidar layer products consist of a sequence of column descriptors, each one of which is associated with a variable number of layer descriptors. The column descriptors specify the temporal and geophysical location of the column of the atmosphere through which a given lidar pulse travels. Also included in the column descriptors are indicators of surface lighting conditions, information about the surface type, and the number of features (e.g., aerosol layers) identified within the column. CALIPSO was launched on April 28, 2006 and continues to collect data necessary to study the impact of clouds and aerosols on the Earth's radiation budget and climate . It flies in the international A-Train constellation for coincident Earth observations. The CALIPSO satellite comprises three instruments, CALIOP, Imaging Infrared Radiometer (IIR), and Wide Field Camera (WFC). CALIPSO is a joint satellite mission between NASA and the French Agency, CNES.

The Global Greenhouse Gas Reference Network for the Carbon Cycle and Greenhouse Gases (CCGG) Group is part of NOAA'S Earth System Research Laboratory (ESRL) in Boulder, CO. The Reference Network measures the atmospheric distribution and trends of the three main long-term drivers of climate change, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as carbon monoxide (CO) which is an important indicator of air pollution. The Reference Network measurement program includes continuous in-situ measurements at 4 baseline observatories (global background sites) and 8 tall towers, as well as flask-air samples collected by volunteers at over 50 additional regional background sites and from small aircraft. The air samples are returned to ESRL for analysis where measurements of about 55 trace gases are done. NOAA's Global Greenhouse Gas Reference Network maintains the World Meteorological Organization international calibration scales for CO2, CH4, CO, N2O, and SF6 in air. The measurements of the Global Greenhouse Gas Reference Network serve as a comparison with measurements made by many other international laboratories, and with regional studies. They are widely used in studies inferring space-time patterns of emissions and removals of greenhouse gases that are optimally consistent with the atmospheric observations. They serve as an early warning for climate "surprises". The measurements are also helpful for the ongoing evaluation of remote sensing technologies. Observatory Measurements: NOAA/ESRL/GMD operates four staffed atmospheric baseline observatories from which numerous measurements of greenhouse gases are conducted. These baseline observatories, also known as global background sites, are located in Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; and South Pole, Antarctica. The measured data are baseline levels, trends, and causes of variability of atmospheric gases that have the potential to affect global climate. These observatories were established in order to provide a sampling of the most remote air on the planet so that the true "background atmosphere" could be monitored. GMD first began continuous in-situ measurements of CO2 at these observatories in 1973, and added CH4 and CO measurements in the 1980's. The ongoing data set is contingent upon the baseline observatories that are still in use going forward. A subset of Observatory Measurements for only carbon dioxide (CO2) taken from Observatories is archived separately with digital object identifiers (DOIs) for each of the four observation stations listed above. The observations run from 1973 through the end of 2016. The main portion of this agreement is for the enhanced "version" of the more encompassing dataset for all of the different types of observation platforms and gases. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.

The Global Greenhouse Gas Reference Network for the Carbon Cycle and Greenhouse Gases (CCGG) Group is part of NOAA'S Earth System Research Laboratory (ESRL) in Boulder, CO. The Reference Network measures the atmospheric distribution and trends of the three main long-term drivers of climate change, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as carbon monoxide (CO) which is an important indicator of air pollution. The Reference Network measurement program includes continuous in-situ measurements at 4 baseline observatories (global background sites) and 8 tall towers, as well as flask-air samples collected by volunteers at over 50 additional regional background sites and from small aircraft. The air samples are returned to ESRL for analysis where measurements of about 55 trace gases are done. NOAA's Global Greenhouse Gas Reference Network maintains the World Meteorological Organization international calibration scales for CO2, CH4, CO, N2O, and SF6 in air. The measurements of the Global Greenhouse Gas Reference Network serve as a comparison with measurements made by many other international laboratories, and with regional studies. They are widely used in studies inferring space-time patterns of emissions and removals of greenhouse gases that are optimally consistent with the atmospheric observations. They serve as an early warning for climate "surprises". The measurements are also helpful for the ongoing evaluation of remote sensing technologies. The CCGG cooperative air sampling network effort began in 1967 at Niwot Ridge, Colorado. Today, the network is an international effort which includes regular discrete samples from the NOAA ESRL/GMD baseline observatories, cooperative fixed sites, and commercial ships. Air samples are collected approximately weekly from a globally distributed network of sites. Samples are analyzed for Carbon Dioxide (CO2), Methane (CH4), Carbon Monoxide (CO), Hydrogen Gas (H2), Nitrous Oxide (N2O), and Sulfur Hexafluoride (SF6); and by INSTAAR for the stable isotopes of CO2 and CH4 and for many volatile organic compounds (voc) such as ethane (C2H6), ethylene (C2H4) and propane (C3H8). Measurement data are used to identify long-term trends, seasonal variability, and spatial distribution of carbon cycle gases. Through the Big Earth Data Initiative (BEDI), ESRL/GMD has taken their data collection and converted files into NetCDF-4, a self-describing format.