COPS Workshop, February 2008 Long-term water vapour comparison at the ARM Mobile Facility S. Crewell, U. Löhnert, S. Kneifel (U Cologne) D. Turner (U Wisconsin)

COPS Workshop, February 2008 Instrumentation at AMF  Radiosondes  IfT Lidar  Microwave Radiometers - MWRP 12ch. - HATPRO - Scanning (Köln) - MWRLOS 2ch. - MWRHF - DPR  GPS Vertical profiles MWRP MWRLOS MWRHF HATPRO DPHASE Integrated Water Vapor (IWV)

COPS Workshop, February 2008 Data Set SourceOrg.Description tt Operation COSMO-DEDWDModel analysis/fore-cast at 3x3 gpoints 15 min04/01-12/ 31 RS-92ARMRadiosonde profiles 919 quality checked 4 / day04/01-12/ 31 GPSGFZ15 min, 93%15 min04/19-12/31 2CHARMStandard ARM dual channel radiometer 20 s04/ /31 MWRPARM12 freqs1 s04/ /31 MWRHFARM90/150 GHz1 s06/20-12/31 HATPROUKölnscanning 14 freqs04/20-12/31 DPRUKölndual pol at 150 GHz1s05/02-10/05 LidarIfTRamanCOPS MSGFUBIWV 3x3 grid15 min04/01-12/31

COPS Workshop, February 2008 Microwave Signatures standard atmosphere liquid water path LWP=250 gm -2 temperature profile humidity profile ν / GHz °91250

COPS Workshop, February 2008 TB Intercomparison Difference in gas absorption from MonoRTM - Rosenkranz 22 GHz water vapor line continuum at higher freqs

COPS Workshop, February 2008 Water vapour during COPS Water on Radome

COPS Workshop, February 2008 Water vapour during COPS 15 min values new best estimate by D. Turner

COPS Workshop, February 2008 Water vapour during COPS agreement between GPS and microwave is worse compared to other sites

COPS Workshop, February 2008 Radiosonde intercomparison Only 12 UTC launches G

COPS Workshop, February 2008 Radiosonde Dry Bias 0 UTC6 UTC12 UTC18 UTCAll N RS - GPS RS - Profiler RS - 2 ch AMF April to June Bias/Std. Deviation in Integrated Water Vapor in kg m -2

COPS Workshop, February 2008 Scanning Microwave Observations COPS: Azimuth scans every 15 min - fixed elevation angle (30°) - 355°- rotation with 5° resolution - beamwidth: HATPRO: ~4-2°, IR: ~1° - scan duration about 5 Min. Integrated Water Vapor (IWV), liquid water path (LWP) and IR-Temperatur along slant path for each azimuth angle

COPS Workshop, February 2008 Exmple: 14 July deg azimuth scans  Morning strong asymmetry of the humidity field  Noon strong humidity reduction of about 5 kgm -2 (in zenith)  13:00-14:30 UTC Convection in the North West  after 15:00 humidity increase see Poster by S. Kneifel

COPS Workshop, February 2008 Summary and Outlook  Water vapour absorption Poorly known at higher microwave frequencies  calibration analysis  Integrated Water Vapor  consistent analysis of all COPS microwave radiometers (calibration, filtering, quality flags, retrieval algorithms..)  Profiles  intercomparisons with IfT Lidar, DLR aircraft lidar  Spatial variabiity More than 10 % variabilty in IWV (see Poster by Kneifel  further analysis of volume scans