Airborne 14-channel microwave radiometer HUTRAD

Hallikainen, M.; Kemppinen, M.; Rautiainen, K.; Pihlflyckt, J.; Lahtinen, J.; Tirri, T.; Mononen, I.; Auer, T.

doi:10.1109/igarss.1996.516963

Cited by 13 publications

(6 citation statements)

References 1 publication

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“…They were installed next to each other on the ice facing the same area but the footprints do not overlap (see Figure S1). The low-frequency system of HUTRAD (Helsinki University of Technology Radiometer) (Hallikainen et al, 1996;Colliander et al, 2007;Lemmetyinen et al, 2009) measures at three frequencies at 6.825, 10.65 and 18.7 GHz, at two orthogonal polarizations H and V. During MOSAiC, HUTRAD had a sampling rate of 1 s, the dataset used here was averaged to 1 minute temporal resolution in order to decrease fluctuations. HUTRAD was observing at a fixed incident angle of 45 • .…”

Section: S4 -Ground-based Radiometer Observationsmentioning

confidence: 99%

Sea ice concentration satellite retrievals influenced by surface changes due to warm air intrusions: A case study from the MOSAiC expedition.

Rückert¹,

Rostosky²,

Huntemann³

et al. 2023

Preprint

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Warm air intrusions over Arctic sea ice can rapidly change the snow and ice surfaceconditions and can alter sea ice concentration (SIC) estimates derived from satellite-based microwave radiometry without altering the true SIC.Here we focus on two warm moist air intrusions that produced surface glazing duringthe Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC)expedition that reached the research vessel Polarstern in mid-April 2020. After theevents, we observe increased SIC deviations between different satellite products,including climate data records, and especially an underestimation of SIC for algorithmsbased on polarization difference.To examine the causes of this underestimation, we use the extensive MOSAiC snowand ice measurements to computationally model the brightness temperatures of thesurface on a local scale. We further investigate the brightness temperatures observedby ground-based radiometers at frequencies 6.9 GHz, 19 GHz and 89 GHz.We show that the drop in the retrieved sea ice concentration of some satellite productscan be attributed to large-scale surface glazing, i.e., the formation of a thin ice crust atthe top of the snowpack, caused by the warming events.Another mechanism affecting satellite products which are mainly based on gradientratios of brightness temperatures, is the interplay of the changed temperature gradientin the snow and snow metamorphism.From the two analyzed climate data record products, one is less affected by thewarming events.The low frequency channels at 6.9 GHz were less sensitive to these snow surfacechanges, which could be exploited in future retrievals of sea ice concentration.

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Section: S4 -Ground-based Radiometer Observationsmentioning

confidence: 99%

Sea ice concentration satellite retrievals influenced by surface changes due to warm air intrusions: A case study from the MOSAiC expedition.

Rückert¹,

Rostosky²,

Huntemann³

et al. 2023

Preprint

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“…The original Helsinki University of Technology Radiometer (HUTRAD) was developed in the 1990's at the Laboratory of Space Technology of the Helsinki University of Technology (Hallikainen et al, 1996). The original system consisted of dual-polarized radiometer receivers at six frequencies (6.8,10.7,18.7,23.8,36.5,and 94 GHz).…”

Section: Hutradmentioning

confidence: 99%

Airborne radiometric measurements at C, X and Ku-Band and�IR imagery

2009

Airborne Radiometric Measurements at C, X and Ku-Band And�IR Imagery

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The airborne campaign CIMREx was initiated by ESA to support the EU Copernicus High Priority Polar Candidate Mission, Copernicus Imaging Microwave Radiometer (CIMR), to sample the sea ice microwave emissions from various sea ice regimes around Svalbard and Greenland. The measurements were carried out with the HUTRAD 2.0 radiometer, refurbished for the purpose of the campaign. HUTRAD measured the brightness temperature from the sea ice at 6.8, 10.65 and 18.7 GHz at vertical and horizontal polarizations, providing basic information on the ability for high-resolution measurements of sea ice concentration and related snow/ice properties for the future CIMR satellite. Refurbishment of HUTRAD was performed as a part of the CIMREx activities by Harp Technologies Ltd. In addition to the sidelooking HUTRAD passive microwave measurements, also infrared and visual imaging was carried out, along with precise aircraft navigation with geodetic GPS and inertial navigation units.The CIMREx campaign took place between February 28-March 11, 2019. The first data were collected during initial transitions from Akureyri, Iceland, via Greenland, to the main campaign site at Svalbard. Three dedicated data collection flights were carried out around Svalbard on March 7 and 8.The work described in this report was done under ESA Contract. Responsibility for the contents resides in the author or organisation that prepared it.

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“…Therefore, multiband microwave radiometers are designed to combine data retrieved from several bands in order to achieve improved measurement. Four examples of multiband microwave radiometers, two airborne and two spaceborne, are mentioned subsequently: The Helsinki University of Technology RADiometer (HUTRAD) for remote sensing is an airborne radiometer which includes a non-imaging subsystem that operates at six frequencies between 6.8 and 94 GHz, with vertically and horizontally polarized channels at each frequency [ 3 ]. The Polarimetric Scanning Radiometer (PSR) is an airborne instrument which operates at 10.7, 18.7, 37, and 89 GHz, and measures the first three modified Stokes’ parameters.…”

Section: Introductionmentioning

confidence: 99%

“…The Helsinki University of Technology RADiometer (HUTRAD) for remote sensing is an airborne radiometer which includes a non-imaging subsystem that operates at six frequencies between 6.8 and 94 GHz, with vertically and horizontally polarized channels at each frequency [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

MERITXELL: The Multifrequency Experimental Radiometer with Interference Tracking for Experiments over Land and Littoral—Instrument Description, Calibration and Performance

Querol

Tarongi

Forte

et al. 2017

Sensors

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MERITXELL is a ground-based multisensor instrument that includes a multiband dual-polarization radiometer, a GNSS reflectometer, and several optical sensors. Its main goals are twofold: to test data fusion techniques, and to develop Radio-Frequency Interference (RFI) detection, localization and mitigation techniques. The former is necessary to retrieve complementary data useful to develop geophysical models with improved accuracy, whereas the latter aims at solving one of the most important problems of microwave radiometry. This paper describes the hardware design, the instrument control architecture, the calibration of the radiometer, and several captures of RFI signals taken with MERITXELL in urban environment. The multiband radiometer has a dual linear polarization total-power radiometer topology, and it covers the L-, S-, C-, X-, K-, Ka-, and W-band. Its back-end stage is based on a spectrum analyzer structure which allows to perform real-time signal processing, while the rest of the sensors are controlled by a host computer where the off-line processing takes place. The calibration of the radiometer is performed using the hot-cold load procedure, together with the tipping curves technique in the case of the five upper frequency bands. Finally, some captures of RFI signals are shown for most of the radiometric bands under analysis, which evidence the problem of RFI in microwave radiometry, and the limitations they impose in external calibration.

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Airborne 14-channel microwave radiometer HUTRAD

Cited by 13 publications

References 1 publication

Sea ice concentration satellite retrievals influenced by surface changes due to warm air intrusions: A case study from the MOSAiC expedition.

Sea ice concentration satellite retrievals influenced by surface changes due to warm air intrusions: A case study from the MOSAiC expedition.

Airborne radiometric measurements at C, X and Ku-Band and�IR imagery

MERITXELL: The Multifrequency Experimental Radiometer with Interference Tracking for Experiments over Land and Littoral—Instrument Description, Calibration and Performance

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