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Radiosonde and ground-based remotely sensed PWV data from the 2004 North Slope of Alaska Arctic Winter Radiometric Experiment. V. Mattioli, E. R. Westwater, D. Cimini, J. S. Liljegren, B. M. Lesht, S. I. Gutman, and F. J. Schmidlin. Submitted to JAOT,10-14-05. Outline.
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Radiosonde and ground-based remotely sensed PWV data from the 2004 North Slope of Alaska Arctic Winter Radiometric Experiment V. Mattioli, E. R. Westwater, D. Cimini, J. S. Liljegren, B. M. Lesht, S. I. Gutman, and F. J. Schmidlin Submitted to JAOT,10-14-05
Outline • Radiosondes launched during the NSA-WVIOP04 experiment • Radiosonde quality control • Analyses of temperature and relative humidity measurements • Comparison of PWV from MWRP, GPS, MWR • PWV day-night differences • Conclusions
Radiosondes launched during the experiment GPS Mark II VAISALA RS90-A 4 times per day at the ARM Duplex (00, 06, 12, 18 UTC) 1 time per day at the ARM “Great White” (00 UTC) Temperature sensor: F-Thermocap (capacitive wire) Humidity sensor: Heated twin-sensor H-Humicap GPS Mark II & Meteolabor “SNOW WHITE” (NASA) 5 at night, 3 during the day Temperature sensor: VIZ short rod thermistor; Humidity sensors: VIZ carbon hygristor; Meteolabor chilled mirror VIZ-B2 (National Weather Service) 2 times per day in Barrow (00, 12 UTC) Temperature sensor: VIZ long rod thermistor; Humidity sensor: VIZ carbon hygristor Dual-radiosonde launches: Vaisala RS90 and Sippican Mark II & Meteolabor Snow White
Dual-sonde launch: Vaisala RS90 and Chilled mirror (2004031101 UTC)
Radiosonde quality control Relative humidity soundings from the Vaisala RS90 launched at the ARM Duplex affected by unrealistic spikes (in general, above 250-200 hPa)
Comparison of temperature measurements VIZ-B2 long rod (NWS-VIZ) vs. Vaisala RS90 capacitive wire (DPLX-RS90) day night
Comparison of relative humidity measurements VIZ-B2 carbon hygristor (NWS-VIZ) vs. Vaisala RS90 twin-sensor thin film capacitor (DPLX-RS90)
Comparison of relative humidity measurements Dual-radiosonde launches at the ARM Duplex: Three humidity sensor: Vaisala RS90 twin-sensor capacitor (DPLX-RS90), VIZ MARK-II carbon hygristor (MK2-CH), Meteolabor Snow White chilled mirror (MK2-SW)
PWV day-night differences day night
Conclusions • Relative humidity soundings from the Vaisala RS90 launched at the ARM Duplex were affected by unrealistic spikes (in general, above 250-200 hPa) • Bias in night-time temperature soundings from the VIZ long rod thermistor for pressures lower than 300 hPa (5ºC at 20 hPa). • RH measurements from the VIZ carbon hygristor (both the NWS-VIZ and the MK2-CH) show an apparent bias with respect to the other sensors above the troposphere (16-20%). Vaisala RS90 and the Snow White chilled mirror have shown good agreement (5% rms). • GPS NRT data in Barrow are affected by a substantial scatter compared to the MWRs. Reprocessing reduced but did not eliminate the scatter. • PWV from the MWRP by using 2 channels (22.235 and 30 GHz) does not provide PWV values with the required accuracy. The use of five channels in the water vapor band provides very good agreement with the MWR (0.034 cm rms) • Diurnal bias of 0.03 cm was found in the PWV radiosonde comparison.Increase the once-a-day sounding at the Great White to twice a day would be of substantial benefit.
Remote sensors Microwave radiometer Profiler (MWRP) five K-band channels (22.235, 23.035, 23.835, 26.235, and 30.0 GHz) and seven V-band channels (51.25, 52.28, 53.85, 54.94, 56.66, 57.29, and 58.8 GHz) Resolution = 0.25 K Accuracy = 0.5 K Microwave radiometer (MWR) Dual-channel: 23.8, 31.4 GHz Resolution = 0.25 K Accuracy = 0.3 K Suominet GPS receiver (SG27) Antenna Type: TRM33429.20+GP Receiver Type: TRIMBLE 4700 GPS data reprocessed by NOAA/Forecast System Laboratory: Software GAMIT; Elevation cut-off 7°; Precise Orbits; 30 min temporal resolution.