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Ground Based Tropospheric Profiling With the RPG-HATPRO 14 Channel Filterbank Radiometer

Ground Based Tropospheric Profiling With the RPG-HATPRO 14 Channel Filterbank Radiometer. Thomas Rose,Harald Czekala ( Radiometer Physics GmbH). RPG-TEMPRO. RPG-TEMPRO90. RPG-HATPRO. RPG-HUMPRO. RPG-LWP. 90 GHz. 23.8 GHz. RPG-LWP-U90. 36.5 /31.4 GHz. Microwave Bands.

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Ground Based Tropospheric Profiling With the RPG-HATPRO 14 Channel Filterbank Radiometer

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  1. Ground Based Tropospheric Profiling With the RPG-HATPRO 14 Channel Filterbank Radiometer Thomas Rose,Harald Czekala (Radiometer Physics GmbH)

  2. RPG-TEMPRO RPG-TEMPRO90 RPG-HATPRO RPG-HUMPRO RPG-LWP 90 GHz 23.8 GHz RPG-LWP-U90 36.5/31.4 GHz Microwave Bands Spectral Bands of Operation: Frequencies: Humidity Profiling: 22-31.4 GHz Band (7 channels) Temp. Profiling (Trop.):50-59 GHz Band (7 channels) Temp. Profiling (BL):54-59 GHz Band (4 channels) LWP / IWV:23.8 / 31.4 + 90 GHz

  3. HATPRO Instrument Configuration

  4. HATPRO Meteorological Station Weather Station and Time Reference: Rain Sensor: Provides rain flag for measurement documentation, control of super blower system GPS-Clock: Provides time reference standard for synchronization Humidity Sensor: Provides control of super blower system, documentation Temperature Sensor: Documentation of surface temperature Humidity Sensor Pressure Sensor: Documentation of baro-metric pressure, LN-target calibration Temp. Sensor Optional IR-Radiometer: Cloud base height detection, ceilometer function

  5. HATPRO Rain / Dew Protection System removable dew blower • Removal of dew and rain by: • strong blower system System allows for temperature profiling during rain

  6. RPG-HATPRO Optical Performance temperature profiler humidity profiler 23.8 GHz, HPBW = 3.9°, Sidelobes: <-30 dB (6.5) 55.0 GHz, HPBW = 1.9°, Sidelobes: <-30 dB (4.0)

  7. Thermal Receiver Stabilisation Two stage thermal stabilisation system: Receiver stabilisation: <30 mK over full opera- ting temperature range (-30°C to + 45°C)

  8. RPG-HATPRO Receiver Layout Dual Profiler Direct Detection Filterbank Receivers based on MMIC Technology:

  9. Synthesizer Emission from Heterodyne System Synthesizer emission from a heterodyne profiling radiometer @ 26.4 GHz detected by RPG-HATPRO during radiometer inter-comparison at DWD / Lindenberg, Germany, Sept./Oct. 2005

  10. Synthesizer Emission from Heterodyne System Heterodyne system turned off: RFI disappears. ‘Passive’ radiometers are sometimes not fully passive but emit interference signals in the RF bands.

  11. 55 dB Pre-Amplifier Splitter and Filter Section Boosters and Detectors Video Amps, MUX, 16 Bit ADC Noise Injection Coupler 51- 59 GHz 7 Channel Filterbank Receiver Corrugated Feedhorn Compact Receiver Design

  12. RPG-HATPRO Receiver Allan Variance Receivers obey radiometer formula: or: Tested up to: tint = 1000 sec 30 sec. Integr. Time → ∆T = 0.1 K

  13. 58 GHz Brightness Temp. Noise in BL Mode 6 days time series of BL mode samples @ 58 GHz, 5° elevation (30 seconds integration time), RMS noise = 0.08 K

  14. Two Scanning Modes (Temperature Profiling) 1) Zenith Mode: vertical viewing direction, 51.26 - 58 GHz, 7 channels, used for full troposphere temperature profiles (<= 10 km) 2) Boundary Layer Mode: vertical Resolution: 50 m (<=1000 m) System Requirements: • Elevation scanning: • 5° - 90° requires narrow • beamwidth (2° HPBW), • leads to 250 mm eff. • beam diameter • low noise channels • long integration periods • parallel acquisition of • all channels • - high receiver stability

  15. RMS Errors of Both Observation Modes solid: boundary layer mode (4 channels) dotted: zenith mode (7 channels) dash-dotted: standard deviation of data set (360 samples) zenith mode zenith mode BL mode BL mode σ data

  16. Inversion Full Trop. Temperature Profile in Zenith Mode Full troposphere (zenith) scan. Inversion below 1km is not well resolved (about 1 K).

  17. Same Inversion Measured in BL Mode 6 hours later A B A: Radiosonde (red) and boundary layer scan (blue) profiles at the same time as above. A strong ground inversion of 4K is resolved. B: 6 hours later the inversion has disappeared (12:00).

  18. Boundary Layer Measured in Zenith Mode Zenith observation mode. In the lower 500 m layer the vertical structure is not resolved in detail (Data taken from 24. July to 28. July 2005 in Convective Storms Initiation Project, University of Salford / UK).

  19. Boundary Layer Measured in BL Mode Boundary layer scanning mode. The vertical structure even in the lowest layer <100 m is clearly resolved.

  20. Boundary Layer Profiles Examples RPG-HATPRO, DWD Lindenberg, Sept. 2005

  21. Boundary Layer Profile Examples Benin, West Africa, January 2006 (AMMA)

  22. Development and Decay of Inversions

  23. Development and Decay of Inversions

  24. Verification of BL Measurements RPG-HATPRO at DWD Lindenberg, Sept. 2005 temp. sensors every 10 m meteorological tower (99 m) RPG-HATPRO

  25. Direct Comparision at 10 / 100 m Levels Mast HATPRO

  26. Direct Comparision at 10 / 100 m Levels Mast HATPRO

  27. dry adiabatic lapse rate Direct Comparision at 10 / 100 m Levels HATPRO mast HATPRO mast HATPRO

  28. bias RMS BL HATPRO/Radiosonde Comparison Distance radiosonde launching site ↔ HATPRO: 4 km

  29. BL Mode HATPRO/Radiosonde Comparison

  30. Strong BL Temperature Inversions RPG-HATPRO at DWD Lindenberg, October 2005

  31. BL HATPRO/Radiosonde Comparison

  32. Zenith Mode HATPRO/Radiosonde Comparison

  33. Zenith Mode HATPRO/Radiosonde Comparison

  34. Zenith Mode HATPRO/Radiosonde Comparison

  35. Zenith Mode HATPRO/Radiosonde Comparison RMS bias

  36. HATPRO Humidity Profiling up to 10 km Benin, West Africa, 19. January 2006 (AMMA) 45 kg/m^2 27 kg/m^2

  37. HATPRO Humidity Profiling Comparison with radiosonde data. RMS Error: 0.5 g/m3

  38. LWP / IWV time series High temp. and spatial res. LWP time series for cloud analysis temp. res.: 1 sec., abs. acc.: +/-20 g/m2 ,RMS Noise: +/- 2 g/m2 30 g/m2 (=0.03 mm)

  39. thunderstorms likely thunderstorms likely 50 TTI 30 KI LI KO -2 Stability Indices Retrieval Lifted Index, K-Index, Showalter Index, Total Totals Index, CAPE (derived from 7 oxygen line and 7 water vapour line channels)

  40. Summary • Direct Detection Filterbank Design offers high temporal resolution, optimum radiometric noise performance and high stability • Superior performance of BL mode in the boundary layer has been demonstrated for temperature profiling • High temporal and spatial resolution for LWP cloud observations • Close to 100% duty cycle for all channels • Low cost due to integrated receiver design and in-house fabrication of all RF components

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