IWRAP: the Imaging Wind and Rain Airborne Profiler for remote sensing of the ocean and the atmospheric boundary layer within tropical cyclones

Fernandez, D.E.; Kerr, Emma; Castells, Anna Martí i; Carswell, J.; Frasier, Stephen J.; Chang, Paul; Black, Peter G.; Marks, Frank D.

doi:10.1109/tgrs.2005.851640

Cited by 40 publications

(16 citation statements)

References 19 publications

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“…IWRAP is a conically scanning dual‐polarized (H and V polarizations) dual‐frequency (C‐ and Ku‐band) airborne Doppler radar that measures Doppler velocity and reflectivity profiles from precipitation as well as ocean surface backscatter at 15‐ to 150‐m resolution simultaneously at four different incidence angles (approximately 30, 35, 40 and 50 degrees) [ Fernandez et al , 2005]. Figure 1 illustrates the measurement technique employed by this instrument.…”

Section: Instrumentation and Processing Methodsmentioning

confidence: 99%

“…For the first time, dual‐polarized C‐ and Ku‐band (roughly 5.3 and 13.5 GHz, respectively) ocean surface NRCS measurements were simultaneously collected with the UMass Imaging Wind and Rain Airborne Profiler (IWRAP), a high‐resolution dual‐band dual‐polarized conically scanning airborne Doppler radar. This radar was designed to study the ocean surface backscatter at low to extreme wind conditions, to analyze the impact of rain on the backscatter measurements, and to study the inner core of TCs [ Fernandez et al , 2005]. In this paper we present coincident vertical and horizontal polarized, high‐resolution C‐ and Ku‐band NRCS observations of ocean surface wind speed events from 25 to 65 m s −1 in absolutely precipitation free areas and at several incidence angles.…”

Section: Introductionmentioning

confidence: 99%

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Dual‐polarized C‐ and Ku‐band ocean backscatter response to hurricane‐force winds

et al. 2006

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[1] Airborne ocean backscatter measurements at C-and Ku-band wavelengths and H and V polarizations at multiple incidence angles obtained in moderate to very high wind speed conditions (25-65 m s À1 ) during missions through several tropical cyclones are presented. These measurements clearly show that the normalized radar cross sections (NRCS) response stops increasing at hurricane-force winds for both frequency bands and polarizations except for high incidence angles at C-band and H polarization. The results also show the mean NRCS departing from a power law behavior for all the presented frequency bands, polarizations, and incidence angles, suggesting a reduction in the drag coefficient. The overall flattening of the azimuthal response of the NRCS is also very apparent in all cases. A new set of geophysical model functions (GMFs) at C-and Kuband are developed from these direct ocean backscatter observations for ocean surface winds ranging from 25 to 65 m s À1. The developed GMFs provide a much more accurate characterization of the NRCS versus wind speed and direction, and their implementation in operational retrieval algorithms from satellite-based scatterometer observations would result in better wind fields. The differences between these measurements and other currently available GMFs, such as QuikSCAT, NSCAT2, CMOD4, and CMOD5, are reported. The implementation of these GMFs in retrieval algorithms will result in better wind fields from satellite-based scatterometers measurements.

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Section: Instrumentation and Processing Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dual‐polarized C‐ and Ku‐band ocean backscatter response to hurricane‐force winds

et al. 2006

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“…We argue in Section 2.3 that this fact does not completely mitigate non-wind sources of T b . As there is more frequent radio frequency interference (RFI) on the lower channels due to other instruments installed on some of the aircraft (e.g., the Imaging Wind and Rain Airborne Profiler [15]), we choose the reference channel to be the highest-frequency channel. The ε f model used in this manuscript is formulated as:…”

Section: Wind Speed Gmfmentioning

confidence: 99%

Stepped Frequency Microwave Radiometer Wind-Speed Retrieval Improvements

et al. 2019

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With the operational deployment of the *SFMR, hurricane reconnaissance and research aircraft provide near real-time observations of the 10 m ocean-surface wind-speed both within and around tropical cyclones. Hurricane specialists use these data to assist in determining wind radii and maximum sustained winds—critical parameters for determining and issuing watches and warnings. These observations are also used for post-storm analysis, model validation, and ground truth for aircraft- and satellite-based wind sensors. We present observations on the current operational wind-speed and rain-rate *SFMR retrieval procedures in the tropical cyclone environment and propose suggestions to improve them based on observed wind-speed biases. Using these new models in the *SFMR retrieval process, we correct an approximate 10% low bias in the wind-speed retrievals from 15 m / s –45 m / s with respect to *GPS dropwindsondes. In doing so, we eliminate the rain-contaminated wind-speed retrievals below 45/ h at tropical storm- and hurricane-force speeds present in the current operational model. We also update the *SFMR *RTM to include recent updates to smooth-ocean emissivity and atmospheric opacity models. All corrections were designed such that no changes to the current *SFMR calibration procedures are required.

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“…The Imaging Wind and Rain Airborne Profiler (IWRAP), initially described in [5], is a dual-frequency conicallyscanning Doppler radar developed by the Microwave Remote Sensing Laboratory at the University of Massachusetts (MIRSL) that is routinely installed on the National Oceanic and Atmospheric Administration's (NOAA) WP-3D research aircraft. IWRAP is primarily designed to study the signature of the ocean surface under wind forcing.…”

Section: Experiments Descriptionmentioning

confidence: 99%

Airborne Dual-Polarization Observations of the Sea Surface NRCS at C-Band in High Winds

Sapp

Frasier

Dvorsky

et al. 2013

IEEE Geosci. Remote Sensing Lett.

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Airborne dual-polarization observations of seasurface normalized radar cross-section (NRCS) were conducted over the North Atlantic during Jan-Feb 2011. Observations were made using the University of Massachusetts' Imaging Wind and Rain Airborne Profiler (IWRAP) radar system installed on the National Oceanic and Atmospheric Administration's (NOAA) WP-3D research aircraft during several winter storm events to determine the high-wind response of the sea-surface NRCS for both horizontal and vertical polarizations. During the flights, the aircraft performed several constant-roll circle maneuvers to allow collection of NRCS over a range of incidence angles. We find consistency with prior reports in the polarization ratio observed at moderate incidence angles at the winds encountered. For larger incidence angles, we observe a measurable decrease in polarization ratio with increasing wind speed.

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IWRAP: the Imaging Wind and Rain Airborne Profiler for remote sensing of the ocean and the atmospheric boundary layer within tropical cyclones

Cited by 40 publications

References 19 publications

Dual‐polarized C‐ and Ku‐band ocean backscatter response to hurricane‐force winds

Dual‐polarized C‐ and Ku‐band ocean backscatter response to hurricane‐force winds

Stepped Frequency Microwave Radiometer Wind-Speed Retrieval Improvements

Airborne Dual-Polarization Observations of the Sea Surface NRCS at C-Band in High Winds

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