The ORNL DAAC recently released an update to the following Atmospheric Tomography Mission (ATom) dataset by Apel, E.C., et al. (2021):
ATom: In Situ Atmospheric Water Vapor from the Diode Laser Hygrometer, Version 2
This dataset provides the concentrations of water measured by the Diode Laser Hygrometer (DLH) flown on the NASA DC-8 during the ATom 1-4 campaigns from 2016 - 2018. The DLH measures the water vapor in the atmosphere by wavelength modulated differential absorption spectroscopy of an isolated rovibrational line. The measurements include water vapor mixing ratio in parts-per-million-by-volume (ppmv) and relative humidity in percent. Relative humidity, both with respect to liquid water and with respect to ice, are quantities derived from measurements of water vapor mixing ratio as well as ambient temperature and pressure.
This Version 2 of this dataset. In Version 2, there are two updated files from 2016-08-12 (DLH-H2O-20Hz_DC8_20160812_R2.ict and DLH-H2O_DC8_20160812_R3.ict). No other files have changed. For addition details see Section 8. Dataset Revisions with the dataset User Guide documentation.
The Atmospheric Tomography Mission (ATom) is a NASA Earth Venture Suborbital-2 mission to study the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Around-the-world flights were conducted in each of four seasons between 2016 and 2018.
Additional data from ATom and other relevant links can be found on the ORNL DAAC's ATom Project Page.
Citation: Diskin, G.S., and J.P. DiGangi. 2021. ATom: In Situ Atmospheric Water Vapor from the Diode Laser Hygrometer, Version 2. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1937