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(1 - 6 of 6)
- Title
- Evaluation of the Hurricane Imaging Radiometer (HIRAD) Brightness Temperatures.
- Creator
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Sahawneh, Saleem, Jones, W Linwood, Mikhael, Wasfy, Wahid, Parveen, Zec, Josko, University of Central Florida
- Abstract / Description
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The Hurricane Imaging Radiometer (HIRAD) is an experimental, airborne, microwave remote sensor that was developed to measure hurricane surface wind speed and rain rate, and thereby, provide data for scientific research and for the next generation operational hurricane surveillance. The object of this dissertation is to develop objective procedures and techniques that can be used to evaluate and characterize the HIRAD brightness temperature (Tb) image product provided by NASA MSFC.First, the...
Show moreThe Hurricane Imaging Radiometer (HIRAD) is an experimental, airborne, microwave remote sensor that was developed to measure hurricane surface wind speed and rain rate, and thereby, provide data for scientific research and for the next generation operational hurricane surveillance. The object of this dissertation is to develop objective procedures and techniques that can be used to evaluate and characterize the HIRAD brightness temperature (Tb) image product provided by NASA MSFC.First, the approach that was developed for geolocation (latitude and longitude) accuracy determination of HIRAD image pixels is presented. Using statistical estimation theory, high-contrast HIRAD imagery are compared with high resolution maps at land/water boundaries, and an error model and measurement results are presented for a variety of pixel locations. Also, a procedure is presented for estimating the HIRAD feature resolution, i.e., the effective spatial resolution (instantaneous field of view, IFOV) in the HIRAD Tb images. Next, the objective technique developed to evaluate HIRAD reconstructed ocean brightness temperature (Tb) images is described and presented. Examples are presented for several ocean scenes, which covers a wide range of ocean wind speed conditions that include Hurricanes. For these cases, surface truth in the form of independent ocean brightness temperatures measurements are obtained by airborne microwave radiometers for comparison.
Show less - Date Issued
- 2017
- Identifier
- CFE0006653, ucf:51221
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006653
- Title
- HURRICANE WIND SPEED AND RAIN RATE RETRIEVAL ALGORITHM FOR THE STEPPED FREQUENCY MICROWAVE RADIOMETER.
- Creator
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Amarin, Ruba, Jones, Linwood, University of Central Florida
- Abstract / Description
-
This thesis presents the development and validation of the Hurricane Imaging Retrieval Algorithm (HIRA) for the measurement of oceanic surface wind speed and rain rate in hurricanes. The HIRA is designed to process airborne microwave brightness temperatures from the NOAA, Stepped Frequency Microwave Radiometer (SFMR), which routinely collects data during NOAA hurricane hunter aircraft flights. SFMR measures wind speeds and rain rates at nadir only, but HIRA will soon be integrated with an...
Show moreThis thesis presents the development and validation of the Hurricane Imaging Retrieval Algorithm (HIRA) for the measurement of oceanic surface wind speed and rain rate in hurricanes. The HIRA is designed to process airborne microwave brightness temperatures from the NOAA, Stepped Frequency Microwave Radiometer (SFMR), which routinely collects data during NOAA hurricane hunter aircraft flights. SFMR measures wind speeds and rain rates at nadir only, but HIRA will soon be integrated with an improved surface wind speed model for expanded utilization with next generation microwave hurricane imagers, such as the Hurricane Imaging Radiometer (HIRad). HIRad will expand the nadir only measurements of SFMR to allow the measurement of hurricane surface winds and rain over a wide swath Results for the validation of HIRA retrievals are presented using SFMR brightness temperature data for 22 aircraft flights in 5 hurricanes during 2003-2005. Direct comparisons with the standard NOAA SFMR empirical algorithm provided excellent results for wind speeds up to 70 m/s. and rain rates up to 50 mm/hr.
Show less - Date Issued
- 2006
- Identifier
- CFE0001313, ucf:47024
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001313
- Title
- Hurricane Imaging Radiometer (HIRAD) tropical rainfall retrievals.
- Creator
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Alasgah, Abdusalam, Jones, W Linwood, Wahid, Parveen, Mikhael, Wasfy, Gong, Xun, Zec, Josko, University of Central Florida
- Abstract / Description
-
The Hurricane Imaging Radiometer (HIRAD) is an airborne passive microwave remote sensor, developed to measure wind speed and rain rate in hurricanes. This dissertation concerns the development of a signal processing algorithm to infer tropical rainfall from HIRAD radiance (brightness temperature, Tb) measurements.The basis of the rain rate retrieval algorithm is an improved forward microwave radiative transfer model (RTM) that incorporates the HIRAD multi-antenna-beam geometry, and uses semi...
Show moreThe Hurricane Imaging Radiometer (HIRAD) is an airborne passive microwave remote sensor, developed to measure wind speed and rain rate in hurricanes. This dissertation concerns the development of a signal processing algorithm to infer tropical rainfall from HIRAD radiance (brightness temperature, Tb) measurements.The basis of the rain rate retrieval algorithm is an improved forward microwave radiative transfer model (RTM) that incorporates the HIRAD multi-antenna-beam geometry, and uses semi-empirical coefficients derived from an airborne experiment that occurred in the Gulf of Mexico off Tampa Bay in 2013. During this flight, HIRAD observed a squall line of thunderstorms simultaneously with an airborne meteorological radar (High Altitude Wind and Rain Profiler, HIWRAP), located on the same airplane. Also, ground based NEXRAD radars from the National Weather Service (located at Tampa and Tallahassee) provided high resolution simultaneous rain rate measurements.Using NEXRAD rainfall as the surface truth input to the HIRAD RTM, empirical rain microwave absorption coefficients were tuned to match the measured brightness temperatures. Also, the collocated HIWRAP radar reflectivity (dBZ) measurements were cross correlated with NEXRAD to derive the empirical HIWRAP radar reflectivity to rain rate relationship. Finally, the HIRAD measured Tbs were input to the HIRAD rain retrieval algorithm to derive estimates of rain rate, which were validated using the independent HIWRAP measurements of rain rate.
Show less - Date Issued
- 2019
- Identifier
- CFE0007775, ucf:52379
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007775
- Title
- DEVELOPMENT OF AN IMPROVED MICROWAVE OCEAN SURFACE EMISSIVITY RADIATIVE TRANSFER MODEL.
- Creator
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El-Nimri, Salem, Jones, W. Linwood, University of Central Florida
- Abstract / Description
-
An electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection...
Show moreAn electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection of published ocean emissivity measurements obtained from satellites, aircraft, field experiments, and laboratory measurements. This dissertation presents the details of methods used in the ocean surface emissivity model development and comparisons with current emissivity models and aircraft radiometric measurements in hurricanes. Especially, this empirically derived ocean emissivity model relates changes in vertical and horizontal polarized ocean microwave brightness temperature measurements over a wide range of observation frequencies and incidence angles to physical roughness changes in the ocean surface, which are the result of the air/sea interaction with surface winds. Of primary importance are the Stepped Frequency Microwave Radiometer (SFMR) brightness temperature measurements from hurricane flights and independent measurements of surface wind speed that are used to define empirical relationships between C-band (4 – 7 GHz) microwave brightness temperature and surface wind speed. By employing statistical regression techniques, we develop a physical-based ocean emissivity model with empirical coefficients that depends on geophysical parameters, such as wind speed, wind direction, sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle.
Show less - Date Issued
- 2010
- Identifier
- CFE0003085, ucf:48323
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003085
- Title
- HURRICANE WIND SPEED AND RAIN RATE MEASUREMENTS USING THE AIRBORNE HURRICANE IMAGING RADIOMETER (HIRAD).
- Creator
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Amarin, Ruba, Jones, W. Linwood, University of Central Florida
- Abstract / Description
-
This dissertation presents results for an end-to-end computer simulation of a new airborne microwave remote sensor, the Hurricane Imaging Radiometer, HIRAD, which will provide improved hurricane surveillance. The emphasis of this research is the retrieval of hurricane-force wind speeds in the presence of intense rain and over long atmospheric slant path lengths that are encountered across its wide swath. Brightness temperature (Tb) simulations are performed using a forward microwave radiative...
Show moreThis dissertation presents results for an end-to-end computer simulation of a new airborne microwave remote sensor, the Hurricane Imaging Radiometer, HIRAD, which will provide improved hurricane surveillance. The emphasis of this research is the retrieval of hurricane-force wind speeds in the presence of intense rain and over long atmospheric slant path lengths that are encountered across its wide swath. Brightness temperature (Tb) simulations are performed using a forward microwave radiative transfer model (RTM) that includes an ocean surface emissivity model at high wind speeds developed especially for HIRAD high incidence angle measurements and a rain model for the hurricane environment. Also included are realistic sources of errors (e.g., instrument NEDT, antenna pattern convolution of scene Tb, etc.), which are expected in airborne hurricane observations. Case studies are performed using 3D environmental parameters produced by numerical hurricane models for actual hurricanes. These provide realistic ÂÂ"nature runsÂÂ" of rain, water vapor, clouds and surface winds from which simulated HIRAD TbÂÂ's are derived for various flight tracks from a high altitude aircraft. Using these simulated HIRAD measurements, Monte Carlo retrievals of wind speed and rain rate are performed using available databases of sea surface temperatures and climatological hurricane atmospheric parameters (excluding rain) as a priori information. Examples of retrieved hurricane wind speed and rain rate images are presented, and comparisons of the retrieved parameters with the numerical model data are made. Statistical results are presented over a broad range of wind and rain conditions and as a function of path length over the full swath.
Show less - Date Issued
- 2010
- Identifier
- CFE0003082, ucf:48330
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003082
- Title
- AN IMPROVED MICROWAVE RADIATIVE TRANSFER MODEL FOR OCEAN EMISSIVITY AT HURRICANE FORCE SURFACE WIND SPEED.
- Creator
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EL-Nimri, Salem, Jones, Linwood, University of Central Florida
- Abstract / Description
-
An electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR),...
Show moreAn electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR), which routinely flys on the National Oceanic and Atmospheric Administration's hurricane hunter aircraft. This thesis presents the methods used in the wind speed model development and validation results for wind speeds up to 70 m/sec. The ocean emissivity model relates changes in measured C-band radiometric brightness temperatures to physical changes in the ocean surface. These surface modifications are the result of the drag of surface winds that roughen the sea surface, produce waves, and create white caps and foam from the breaking waves. SFMR brightness temperature measurements from hurricane flights and independent measurements of surface wind speed are used to define empirical relationships between microwave brightness temperature and surface wind speed. The wind speed model employs statistical regression techniques to develop a physics-based ocean emissivity model dependent on geophysical parameters, such as wind speed and sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle.
Show less - Date Issued
- 2006
- Identifier
- CFE0001312, ucf:47019
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001312
