Hurricane Wind Speed Measurements in Rainy Conditions Using the Airborne Hurricane Imaging Radiometer (HIRAD)

Amarin, Ruba; Jones, W. Linwood; El-Nimri, Salem; Johnson, James W.; Ruf, Christopher S.; Miller, Timothy L.; Uhlhorn, Eric W.

doi:10.1109/tgrs.2011.2161637

Cited by 24 publications

(9 citation statements)

References 10 publications

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“…The HIRAD concept was based upon simultaneously obtaining brightness temperature images of the hurricane at several widely-spaced microwave frequencies, which allows for the retrieval of both ocean wind speed (WS) and rain rate (RR). Before the hardware development and flight testing of HIRAD, theoretical studies were performed that demonstrated that accurate WS and RR retrievals were possible in the presence of expected random instrument T b measurement errors [1,[3][4][5]. However, for a number of reasons, the proof of concept for the HIRAD remote sensor has yet to come to fruition.…”

Section: Rain Impact On Retrievalsmentioning

confidence: 99%

“…The HIRAD forward RTM was developed by Amarin [1,5] and El-Nimiri [13,14] to calculate the brightness temperature at the HIRAD antenna aperture based on the push-broom line-of-sight (LOS) measurement geometry ( Figure 2) that input environmental parameters from the atmosphere and the ocean surface, as shown in Figure 7. The scene brightness temperature (T app ) at the top of the atmosphere (TOA) is the scalar sum of three T b components along the HIRAD antenna beam LOS, namely: the upwelling atmospheric emission (T up ), the ocean surface emission (T sur ), and the downwelling atmospheric emission that is specularly reflected at the ocean surface.…”

Section: Hirad Rtmmentioning

confidence: 99%

“…This paper describes the first experimental validation of a forward microwave radiative transfer model (RTM) for ocean scenes with strong tropical precipitation that was developed for the airborne Hurricane Imaging Radiometer [1]. Prior to this paper, this RTM has been used to simulate multi-frequency brightness temperature observations for the HIRAD airborne measurement geometry over hurricanes.…”

Section: Introductionmentioning

confidence: 99%

“…HIRAD RTM geometry with separate upwelling (blue) and downwelling (red) paths from Amarin[1].Remote Sens. 2019, 11, 2650 8 of 22…”

mentioning

confidence: 99%

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Validation of the Hurricane Imaging Radiometer Forward Radiative Transfer Model for a Convective Rain Event

et al. 2019

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The airborne Hurricane Imaging Radiometer (HIRAD) was developed to remotely sense hurricane surface wind speed (WS) and rain rate (RR) from a high-altitude aircraft. The approach was to obtain simultaneous brightness temperature measurements over a wide frequency range to independently retrieve the WS and RR. In the absence of rain, the WS retrieval has been robust; however, for moderate to high rain rates, the joint WS/RR retrieval has not been successful. The objective of this paper was to resolve this issue by developing an improved forward radiative transfer model (RTM) for the HIRAD cross-track viewing geometry, with separated upwelling and specularly reflected downwelling atmospheric paths. Furthermore, this paper presents empirical results from an unplanned opportunity that occurred when HIRAD measured brightness temperatures over an intense tropical squall line, which was simultaneously observed by a ground based NEXRAD (Next Generation Weather Radar) radar. The independently derived NEXRAD RR created the simultaneous 3D rain field “surface truth”, which was used as an input to the RTM to generate HIRAD modeled brightness temperatures. This paper presents favorable results of comparisons of theoretical and the simultaneous, collocated HIRAD brightness temperature measurements that validate the accuracy of this new HIRAD RTM.

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Section: Rain Impact On Retrievalsmentioning

confidence: 99%

Section: Hirad Rtmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…HIRAD RTM geometry with separate upwelling (blue) and downwelling (red) paths from Amarin[1].Remote Sens. 2019, 11, 2650 8 of 22…”

mentioning

confidence: 99%

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Validation of the Hurricane Imaging Radiometer Forward Radiative Transfer Model for a Convective Rain Event

et al. 2019

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“…Surface wind speeds for the cold calibration targets are taken from dropsondes, with wind speeds less than 7 m s −1 . A fixed atmospheric profile of temperature, water vapor, and cloud liquid water is taken from idealized numerical simulations of hurricanes described by Amarin et al (2012). At HIRAD’s C-band frequencies, sensitivity to realistic variations in these atmospheric profiles is small (Smith 1982; Tsang et al 1977) compared to the instrument’s measurement error.…”

Section: Hirad Data Processing and Scene Constructionmentioning

confidence: 99%

Assimilating Global Wave Model Predictions and Deep-Water Wave Observations in Nearshore Swell Predictions

Cecil

Biswas

2017

Journal of Atmospheric and Oceanic Technology

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Surface wind speed retrievals have been generated and evaluated using Hurricane Imaging Radiometer (HIRAD) measurements from flights over Hurricane Joaquin, Hurricane Patricia, Hurricane Marty, and the remnants of Tropical Storm Erika, all in 2015. Procedures are described here for producing maps of brightness temperature, which are subsequently used for retrievals of surface wind speed and rain rate across a ~50 km wide swath for each flight leg. An iterative retrieval approach has been developed to take advantage of HIRAD’s measurement characteristics. Validation of the wind speed retrievals has been conducted, using 636 dropsondes released from the same WB-57 high altitude aircraft carrying HIRAD during the Tropical Cyclone Intensity (TCI) experiment. The HIRAD wind speed retrievals exhibit very small bias relative to the dropsondes, for winds tropical storm strength (17.5 m s−1) or greater. HIRAD has reduced sensitivity to winds weaker than tropical storm strength, and a small positive bias (~2 m s−1) there. Two flights with predominantly weak winds according to the dropsondes have abnormally large errors from HIRAD, and large positive biases. From the other flights, root mean square differences between HIRAD and the dropsonde winds are 4.1 m s−1 (33%) for winds below tropical storm strength, 5.6 m s−1 (25%) for tropical storm strength winds, and 6.3 m s−1 (16%) for hurricane strength winds. Mean absolute differences for those categories are 3.2 m s−1 (25%), 4.3 m s−1 (19%), and 4.8 m s−1 (12%), with bias near zero for tropical storm and hurricane strength winds.

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A new algorithm for sea-surface wind-speed retrieval based on the L-band radiometer onboard Aquarius

Wang

Zhang²,

Fan³

2014

Chin. J. Ocean. Limnol.

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Hurricane Wind Speed Measurements in Rainy Conditions Using the Airborne Hurricane Imaging Radiometer (HIRAD)

Cited by 24 publications

References 10 publications

Validation of the Hurricane Imaging Radiometer Forward Radiative Transfer Model for a Convective Rain Event

Validation of the Hurricane Imaging Radiometer Forward Radiative Transfer Model for a Convective Rain Event

Assimilating Global Wave Model Predictions and Deep-Water Wave Observations in Nearshore Swell Predictions

A new algorithm for sea-surface wind-speed retrieval based on the L-band radiometer onboard Aquarius

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