- Microwave Remote Sensing Instruments
Microwave Scintillometer RPG-MWSC-160
The microwave scintillometer RPG-MWSC-160 provides latent and sensible heat flux observations within the atmospheric surface layer, when it is conbined with an optical Large Aperture Scintillometer (LAS).
In 2014 Radiometer Physics GmbH (RPG) released the first commercially available microwave scintillometer RPG-MWSC-160. It was designed for combined operation with an optical Large Aperture Scintillometer (LAS) to observe sensible and latent heat fluxes at the same time.
Areas of Application
Measurement of sensible heat flux and evapotranspiration (latent heat flux) significant for:
- Water management
- Forest fire warning
- Weather forecasting
- Radiation budget studies
|Frequency||160.8 GHz (λ=1.86 mm)|
|Radiated Power||maximum power: >25 mW, 50 dB attenuator|
|Antenna Type||Cassegrain with 300 mm aperture|
|Antenna Gain||52 dB|
|Beam Width||0.45° FWHM|
|Detection Bandwidth||10 kHz|
|Gain Stability||> 2.0 × 10-5|
|Temperature Stability||< 0.03 K (two-stage control)|
|Power Supply||12 V DC|
|Power Sonsumption||max. 50 W (per unit), 20 W typical (receiver), 15 W typical (transmitter)|
|Output Data|| |
Level 0: 1 kHz digital raw data for RPG-MWSC-160 and LAS; housekeeping data
Level 1: (co)variances of the combined MWSC/LAS system
Level 2: structure parameters; sensible and latent heat fluxes (with weather station)
|Type of installation||Line of sight Tx/Rx system (transmit/receive)|
|Baseline Length||500 m to 10 km|
The RPG-MWSC-160 prototype was developed by RPG and Wageningen University
(The Netherlands) within the OMS (Optical and Microwave Scintillation) project. The RPG-MWSC-160 uses hardware developments from space projects.
- High frequency (160.8 GHz) for good co-spectrum with LAS
- Large aperture (300 mm) provides small beam width
- Tunable power level (max. >25 mW) allows path length between 500 m and 10 km
- Low weight (~10 kg) and power consumption (~20 W)
Retrieved data types:
- Structure parameters Cn2 of the turbulent surface layer
- Sensible and latent heat fluxes (in combination with an optical Large Aperture Scintillometer (LAS))
RPG-MWSC-160 was tested in mid-latitude continental climate. It was operated in combination with two LAS systems over a long signal path between two measurement towers with an observation height of approximately 45 m. The setup is characterized by inhomogeneous landscape with patches of woodland, lakes and crops. The combined scintillometer measurements provide heat fluxes with a Bowen ratio around 1. Measurements are in good agreement with Eddy-Covariance (EC) station data.
Measurement time series for a long path over heterogeneous landscape (September 8, 2013, Germany). Left: refractive index structure parameters for RPG-MWSC-160, optical LAS, and for the signal covariance (COV) of both instruments (OMS method, Lüdi et al. ). Right: estimates of path integrated sensible heat flux H and latent heat flux LvE. Circles give measurements from a Eddy Covariance station (EC).
In July 2014 the re-design of the RPG-MWSC-160 prototype was tested in combination with a LAS (Kipp&Zonen® Mk-II) and RPG’s operating software. Data processing now includes surface sensor data from the integrated external weather station (Lufft® WS600-UMB). A one hour time series of heat fluxes under variable cloudiness is given below. Observations were performed over a dry rapeseed field.
Power spectra, raw signals and variances are continuously displayed.
Correlation coefficient RTQ and heat fluxes H and LvE.