Humidity And Temperature PROfilers


RPG’s profiling radiometers are mainly used to derive vertical profiles of atmospheric temperature and humidity (RPG-HATPRO). The infrared radiometer extension allows to cloud base height and ice cloud detection.The radiometer series covers high-resolution temperature profiling of the boundary layer and low-humidity applications. All models of the series provide accurate total amounts of atmospheric water vapor and cloud liquid cloud. RPG radiometers are stand-alone systems for automated weather-station use under nearly all environmental conditions.  A variety of retrieval algorithms (custom designed and global standard algorithms) can be selected.


Meteorological observations, Numerical Weather Prediction (NWP), forecasting, now-casting, climate monitoring, aviation meteorology, astronomy, geodesy.


Two bands, 22-31 GHz (7 channel filter bank humidity profiler and LWP radiometer) and 51-58 GHz (7 channel filter bank temperature profiler)

Retrieved data types:

  • vertical profiles of atmospheric temperature
  • vertical profile of atmospheric humidty (relative and absolute humidity)
  • Liquid Water Path (LWP)
  • Integrated Water Vapor (IWV)
  • wet delay
  • dry delay
  • stability indices

This system is very similar to the RPG-LWP liquid water path (two channel) radiometer: Only the receiver systems vary, housing and additional sensors are basically the same.


Different model types of profiling radiometers are available.

Model Frequencies Applications


22.24 – 31.4 GHz,
51.0 – 58.0 GHz
Humidity + temperature profiles (high precision in boundary layer), clouds, IWV, LWP, stability


51.0 – 58.0 GHz, 183.31 GHz
(6 DSB-channels to ±7.5 GHz)
Like HATPRO, but for Low-humidity (high altitudes, cold environments, PWV < 3 mm)
TEMPRO 51.0 – 58.0 GHz Temperature profiles, Boundary layer temperature profiling
HUMPRO 22.24 – 31.4 GHz Humidity profiles, clouds, IWV, LWP


183.31 GHz (6 DSB-channels up to ±7.5 GHz) Low-Humidity high-precision profiles (clouds: limited accuracy)
Parameter Specification
Humidity profile performance
(zenith and along track)
Vertical resolution: 200 m (range 0-2000 m)
                               400 m (range 2000-5000 m)
                               800 m (range 5000-10000 m)
Accuracy: 0.3 g/m3 maximum bias typical (abs. humidity)
0.1 g/m3 RMS typical (absolute hum.)
                 5% RMS (rel. humidity)
Temperature profile performance
(zenith and along track)
Vertical resolution:
BL-Mode:    30 m (range 0-1200 m)
Z-Mode:    200 m (range 1200-5000 m)
                 400 m (range 5000-10000 m)
Accuracy: 0.25 K RMS (range 0-500 m)
                 0.50 K RMS (range 500-1200 m)
                 0.75 K RMS (range 1200-4000 m)
                 1.00 K RMS (range 4000-10000 m)
Liquid water profile performance
(only with IR radiometer option)
Vertical resolution:
250 m (range 0-2000 m)
300 m (range 2000-5000 m)
500 m (range 5000-10000 m)


cloud base height: 50 m (range 0-300 m)
                            100 m (range 300-1000 m)
                            200 m (range 1000-3000 m)
                            400 m (range 3000-5000 m)
                            600 m (range5000-10000 m)
density: 0.03 g/m3 RMS
Threshold: 50 g/m2 LWP
Only single layer clouds are modelled
IR radiometer option 9.6-11.5 µm band, accuracy 1 K, noise: 0.2 K RMS
LWP Accuracy: ± 20 g/m2, Noise: 2 g/mRMS
IWV Accuracy: ± 0.2 kg/m2 RMS, Noise: 0.05 kg/mRMS
Full sky IWV and LWP maps (only with azimuth positioner)
350 points in 6 minutes rapid scanning
Satellite tracking mode
(only with azimuth positioner option)
Determines wet/dry delay, atmospheric attenuation and humidity profiles along line of sight for all visible GPS / Galileo satellites in a single scan (2 minutes)

scanning with RINEX navigation file or direct GPS vector reading from GPS clock

Channel centre frequencies K-Band: 22.24 GHz, 23.04 GHz, 23.84 GHz, 25.44 GHz, 26.24 GHz, 27.84 GHz, 31.4 GHz

V-Band: 51.26 GHz, 52.28 GHz, 53.86 GHz, 54.94 GHz, 56.66 GHz, 57.3 GHz, 58.0 GHz

Channel bandwidth 2000 MHz @ 58.0 GHz, 1000 MHz @ 57.3 GHz, 600 MHz @ 56.66 GHz, 230 MHz @ all other
System noise temperatures <400 K typical for  22.2 – 31.4 GHz profiler <600 K typical for  51.4 – 58.0 GHz profiler
Radiometric resolution K-Band: 0.10 K RMS,
V-Band: 0.15 K RMS (at 1 sec int. time)
Absolute brightness temperature accuracy
0.5 K
Radiometric range 0-800 K
Absolute calibration with internal ambient & external cold load
Internal calibration gain: with internal noise standard

gain + system noise: ambient temperature target + noise standard

abs. cal. of  humidity profiler: sky tipping calibration

Receiver and antenna thermal stabilization Stability better than 0.03 K over full operating temperature range
Gain nonlinearity error correction Automatic, four point method
Brightness calculation based on exact Planck radiation law
Integration time ≥ 0.4 seconds for each channel, user selectable
Sampling rate for profiles ≥ 1 sec, user selectable
Rain / fog mitigation system Highly efficient blower system (130 Watts), hydrophobic coated microwave transparent window, 1.8 kW heater module preventing formation of dew under fog conditions
Environmental Sensors On a 1-meter mast attached to the radiometer:

  • Temperature, pressure, relative humidity
  • Wind speed, wind direction
Data interface / rate Ethernet (TCP/IP)
Instrument control (external PC) Windows™ System with Ethernet interface
Instrument control (internal) Embedded PC, controls all internal calibrations, data acquisition, data file backup on 10 GB flash memory, control of azimuth positioner, communication with host, can run measurements independently from host PC
Housekeeping all system parameters, calibration history documentation
Retrieval algorithms neural network, linear /nonlinear regression algorithms
Optical resolution HPBW (frequency dependent): 3.0° – 4.2° for water vapour, 1.8° – 2.2° for temperature profiler
Side-lobe level <-30dBc
Pointing range / resolution Elevation: 0° to 180° (0.15° steps), full s/w control
Azimuth (optional): 0° to 360° (0.1° steps), full s/w control
Pointing speed 45°/sec (elevation), 40°/sec (azimuth, optional)
Operating temperature range -40°C to +45°C
Power consumption <120 Watts average, 350 Watts peak for warming-up (without dew blower heater), blower: 130 Watts max.
Lightning protection Power line: circuit breakers

Data line: Fibre optics cable (max. length: 1400 m)

Input voltage 90-230 V AC, 50 to 60 Hz
Weight 60 kg (without dew blower)
Dimensions 63 × 36 × 90cm3
Weather station Lufft WS600-UMB
  • Network capability through Ethernet Interface
  • Optical resolution: HPBW (frequency dependent): 3.0°-4.2° for water vapor, 1.8°-2.2° for temperature profiler.
  • Radiometric resolution: K-Band: 0.10 K RMS, V-Band: 0.15 K (at 1 sec integration time).
  • High repetition rate: filter bank receiver produces one atmospheric profile per second
  • Absolute system stability: 0.5 K
  • Receiver and antenna thermal stabilization: < 0.02 K
  • Operating temperature range: –40°C to +45°C
  • Automatic rain-mitigation system: hydrophobic coating and strong blower for rain, heater module with 1.8 kW preventing formation of dew and fog condensation on radome
  • Integrated PC on-board
  • Comprehensive operating software included (free updates)
  • Full internal retrieval algorithm, retrieval data and raw data output
  • GPS clock and receiver
  • Additional external meteorological sensors: barometric pressure, humidity, temperature, wind (direction and speed), rain rate
  • IR-radiometer option for cloud base height detection and ice cloud detection
  • Azimuth positioner option for full sky scanning (350 samples in less than 6 minutes)
  • North-alignment by software feature (sun-tracking plus GPS, only with azimith positioner)
  • Fiber-optics data cable to connect radiometer to controlling host PC (maximum length 1600 m)
  • Customized retrieval software available
  • Stand alone operation
  • Data storage and backup on-board, power-failure safe-guard
  • Low maintenance (6 months intervall for absolute calibration using LN2)
  • Power supply: 100 – 240 V AC (at 47 – 63 Hz)
  • Power consumption: <120 W average, 350 W peak during warm-up, blower 130 W maximum.
  • Weight: 60 kg (without dew blower)
  • Dimensions: 63 × 40 × 90 cm (H × W × L, without stand)
  • Low cost!