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Ed R. Westwater (1) , Domenico Cimini (2) , Vinia Mattioli (3) ,

The 2004 North Slope of Alaska Arctic Winter Radiometric Experiment: Overview and Highlights. Ed R. Westwater (1) , Domenico Cimini (2) , Vinia Mattioli (3) , Al Gasiewski (4) , Marian Klein (2) , Vladimir Leuski (2) , and Jim Liljegren (5)

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Ed R. Westwater (1) , Domenico Cimini (2) , Vinia Mattioli (3) ,

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  1. The 2004 North Slope of Alaska Arctic Winter Radiometric Experiment: Overview and Highlights Ed R. Westwater(1), Domenico Cimini(2), Vinia Mattioli(3) , Al Gasiewski(4), Marian Klein(2), Vladimir Leuski(2), and Jim Liljegren(5) (1) Cooperative Institute for Research in Environmental Sciences, University of Colorado/NOAA-Environmental Technology Laboratory, 325 Broadway ,Boulder, CO 80305, USA, Tel. +1-303-497-6527, Email: Ed.R.Westwater@noaa.gov (2) Cooperative Institute for Research in Environmental Sciences, University of Colorado/NOAA-Environmental Technology Laboratory, 325 Broadway ,Boulder, CO 80305, USA (3)Dipartimento di Ingegneria Elettronica e dell'Informazione, Università di Perugia via G. Duranti 93, 06125 Perugia, Italy, (4) NOAA-Environmental Technology Laboratory, 325 Broadway , Boulder, CO 80305, USA (5) DOE/Argonne National Laboratory, Bldg 203, 9700 South Cass Avenue, Argonne, IL 60439, USA MicroRad2006 San Juan, Puerto Rico

  2. MOTIVATION • Moisture and clouds in the cold, dry polar regions play key roles in climate feedback • Development of accurate Radiative Transfer models requires accurate measurement of water vapor • The accuracy of Radiosonde-derived humidity is difficult to access in arctic environments • Both Microwave Radiometers and GPS are not sensitive to precipitable water vapor amounts (PWV < 3 mm) • Radiometers operating near 183.31 GHz offer greatly-enhanced sensitivity to vapor MicroRad2006 San Juan, Puerto Rico

  3. The Arctic Winter Radiometric Experiment WVIOP2004 • Period: March 9-April 9 2004 • Location: ARM NSA, Barrow, Alaska • Instruments: • Dual channel Microwave Radiometer (MWR) • 12-channel Microwave Radiometer Profiler (MWRP) • 25-channel Ground-based Scanning Radiometer (GSR) • GPS receiver • 6-hourly radiosonde launches at 3 sites (4 kinds of humidity sensors) GSR MWRP MWR MicroRad2006 San Juan, Puerto Rico

  4. GOALS OF EXPERIMENTNORTH SLOPE OF ALASKAMarch 9-April 9 2004 ● Compare microwave vs. millimeterwave radiometric response to low amounts of water vapor and arctic clouds ● Obtain data for forward model radiative transfer studies at frequencies ranging from 22.235 to 340 GHz: radiosonde soundings; IR, radar and lidar for cloud identification; well-calibrated radiometers ● Demonstrate new NOAA radiometric receiver and calibration technology (see presentation by Cimini et al., this conference) MicroRad2006 San Juan, Puerto Rico

  5. WVIOP2004 Time series of meteorological variables MicroRad2006 San Juan, Puerto Rico

  6. WVIOP2004 Time series of brightness temperatures 10 mm 340 GHz 183±7 GHz 183±16 GHz 89 GHz 22.2 GHz 31.4 GHz MicroRad2006 San Juan, Puerto Rico

  7. Tb response to PWV during clear-sky 340 GHz 183±7 GHz 183±16 GHz 89 GHz 22.2 GHz 31.4 GHz MicroRad2006 San Juan, Puerto Rico

  8. Tb response to LWP during cloudy-sky MicroRad2006 San Juan, Puerto Rico

  9. PWV sensitivity for MW- and mm-wave channels (PWV<1.5 mm) After Racette et al.* WVIOP2004 (measured) MicroRad2006 San Juan, Puerto Rico 0.5<PWV<1.5 mm 0.8<PWV<1.5 mm *simulations based on Rosenkranz 1998 model

  10. Tb response to LWP during cloudy-sky MicroRad2006 San Juan, Puerto Rico

  11. LWP sensitivity for MW- and mm-wave channels (0.0<LWP<0.5 mm) MicroRad2006 San Juan, Puerto Rico

  12. 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 MicroRad2006 San Juan, Puerto Rico

  13. Comparison of temperature measurements VIZ-B2 long rod (NWS-VIZ) vs. Vaisala RS90 capacitive wire (DPLX-RS90) day night MicroRad2006 San Juan, Puerto Rico

  14. Comparison of relative humidity measurements VIZ-B2 carbon hygristor (NWS-VIZ) vs. Vaisala RS90 twin-sensor thin film capacitor (DPLX-RS90) MicroRad2006 San Juan, Puerto Rico

  15. Water Vapor Weighting Functions for Microwave Radiometric Profiler MicroRad2006 San Juan, Puerto Rico

  16. Comparison of Measured vs. Calculated Brightness Temperature at 22.235 GHz DPLX RAOBS LILJ04 NWS RAOBS LILJ04 MicroRad2006 San Juan, Puerto Rico

  17. FORWARD MODEL AND RADIOSONDE COMPARISONS:INPUT TO MODELS = T, RH, AND P FROM RADIOSONDESCLEAR SKIES DETERMINED FROM MWRP IR ModelsRadiosondes ●Liebe 1987 ● Vaisala RS90 (Dplx) ●Liebe 1993 ● Chilled mirror ● Rosenkranz (1998) ● VIZ (NASA) ● Rosenkranz (2003) ● Vaisala RS90 (GW) ● Liljegren (2005) ● VIZ(NWS) MicroRad2006 San Juan, Puerto Rico

  18. Comparison of Tb forward models for a Chilled Mirror Humidity Sensor MicroRad2006 San Juan, Puerto Rico

  19. MicroRad2006 San Juan, Puerto Rico

  20. Summary and conclusions Mm- and submm-wavelength channels offer greatly-enhanced sensitivity to PWV and LWP in Arctic conditions Comparing the sensitivity to low PWV with respect to 23.8 GHz: 183±16, 183±7, 183±3, 183±1 GHz show 11, 25, 54, 69 times larger sensitivity, respectively 340 GHz shows 33 times larger sensitivity Comparing the sensitivity to low LWP with respect to 31.4 GHz: 89 GHz shows 3.3 times larger sensitivity to LWP 183±15 GHz shows 4.1 times larger sensitivity to LWP Due to the non-linear response, non-linear retrieval techniques are being developed for mm- and sub mm-wave observations (Cimini et al.) At the climatically important location of Barrow, Alaska, the climate records based on NWS radiosondes are incorrect in the upper troposphere-lower stratosphere MicroRad2006 San Juan, Puerto Rico

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