Water vapor mass mixing ratio profiles from NASA’s Lidar Atmospheric Sensing Experiment (LASE) systemacquired during the Atmospheric Radiation Measurement (ARM)–First International Satellite Cloud ClimatologyProject (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX) are used as a reference tocharacterize upper-troposphere water vapor (UTWV) measured by ground-based Raman lidars, radiosondes, andin situ aircraft sensors over the Department of Energy (DOE) ARM Southern Great Plains (SGP) site in northernOklahoma. LASE was deployed from the NASA DC-8 aircraft and measured water vapor over the ARM SGPCentral Facility (CF) site during seven flights between 27 November and 10 December 2000. Initially, the DOEARM SGP Cloud and Radiation Testbed (CART) Raman lidar (CARL) UTWV profiles were about 5%–7%wetter than LASE in the upper troposphere, and the Vaisala RS80-H radiosonde profiles were about 10% drierthan LASE between 8 and 12 km. Scaling the Vaisala water vapor profiles to match the precipitable water vapor(PWV) measured by the ARM SGP microwave radiometer (MWR) did not change these results significantly.By accounting for an overlap correction of the CARL water vapor profiles and by employing schemes designedto correct the Vaisala RS80-H calibration method and account for the time response of the Vaisala RS80-Hwater vapor sensor, the average differences between the CARL and Vaisala radiosonde upper-troposphere watervapor profiles are reduced to about 5%, which is within the ARM goal of mean differences of less than 10%.The LASE and DC-8 in situ diode laser hygrometer (DLH) UTWV measurements generally agreed to withinabout 3%–4%. The DC-8 in situ frost point cryogenic hygrometer and Snow White chilled-mirror measurementswere drier than the LASE, Raman lidars, and corrected Vaisala RS80H measurements by about 10%–25% and10%–15%, respectively. Sippican (formerly VIZ Manufacturing) carbon hygristor radiosondes exhibited largevariabilities and poor agreement with the other measurements. PWV derived from the LASE profiles agreed towithin about 3% on average with PWV derived from the ARM SGP microwave radiometer. The agreementbetween the LASE and MWR PWV and the LASE and CARL UTWV measurements supports the hypothesesthat MWR measurements of the 22-GHz water vapor line can accurately constrain the total water vapor amountand that the CART Raman lidar, when calibrated using the MWR PWV, can provide an accurate, stable referencefor characterizing upper-troposphere water vapor.
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