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EVALUATION OF A MICROWAVE RADIATIVE TRANSFER MODEL FOR CALCULATING SATELLITE BRIGHTNESS TEMPERATURE
Title
EVALUATION OF A MICROWAVE RADIATIVE TRANSFER MODEL FOR CALCULATING SATELLITE BRIGHTNESS TEMPERATURE.
Creator
Thompson, Simonetta, Jones, Linwood, University of Central Florida
Abstract / Description
Remote sensing is the process of gathering and analyzing information about the earth's ocean, land and atmosphere using electromagnetic "wireless" techniques. Mathematical models, known as Radiative Transfer Models (RTM), are developed to calculate the observed radiance (brightness temperature) seen by the remote sensor. The RTM calculated brightness temperature is a function of fourteen environmental parameters, including atmospheric profiles of temperature, pressure and moisture, sea...
Show moreRemote sensing is the process of gathering and analyzing information about the earth's ocean, land and atmosphere using electromagnetic "wireless" techniques. Mathematical models, known as Radiative Transfer Models (RTM), are developed to calculate the observed radiance (brightness temperature) seen by the remote sensor. The RTM calculated brightness temperature is a function of fourteen environmental parameters, including atmospheric profiles of temperature, pressure and moisture, sea surface temperature, and cloud liquid water. Input parameters to the RTM model include data from NOAA Centers for Environmental Prediction (NCEP), Reynolds weekly Sea Surface Temperature and National Ocean Data Center (NODC) WOA98 Ocean Salinity and special sensor microwave/imager (SSM/I) cloud liquid water. The calculated brightness temperatures are compared to collocated measurements from the WindSat satellite. The objective of this thesis is to fine tune the RadTb model, using simultaneous environmental parameters and measured brightness temperature from the well-calibrated WindSat radiometer. The model will be evaluated at four microwave frequencies (6.8 GHz, 10.7 GHz, 18.7 GHz, and 37.0 GHz) looking off- nadir for global radiance measurement.
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Date Issued
2004
Identifier
CFE0000318, ucf:46280
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000318
Engineering Evaluation of Multi-beam Satellite Antenna Boresight Pointing using Land/Water Crossings
Title
Engineering Evaluation of Multi-beam Satellite Antenna Boresight Pointing using Land/Water Crossings.
Creator
May, Catherine, Jones, W, Mikhael, Wasfy, Wahid, Parveen, University of Central Florida
Abstract / Description
The Microwave Radiometer (MWR) on the Aquarius/SAC-D mission measures microwave radiation from earth and intervening atmosphere in terms of brightness temperature (Tb). It takes measurements in a push-broom fashion at K (23.8GHz) and Ka (36.5 GHz) band frequencies using two separate antenna systems, each producing eight antenna beams. Pre-launch knowledge of the alignment of these beams with respect to the space-craft is used to geolocate the antenna footprints on ground. As a part of MWR's...
Show moreThe Microwave Radiometer (MWR) on the Aquarius/SAC-D mission measures microwave radiation from earth and intervening atmosphere in terms of brightness temperature (Tb). It takes measurements in a push-broom fashion at K (23.8GHz) and Ka (36.5 GHz) band frequencies using two separate antenna systems, each producing eight antenna beams. Pre-launch knowledge of the alignment of these beams with respect to the space-craft is used to geolocate the antenna footprints on ground. As a part of MWR's on-orbit engineering check-out, the verification of MWR's pointing accuracy is discussed here. The technique used to assess MWR's pointing involved comparing the radiometer image of land with high-resolution maps. When the beam's instantaneous field of view (IFOV) passes over a land water boundary, the brightness temperature changes from a radiometrically hot land scene to a radiometrically cold ocean scene. This (")step-function(") change in brightness temperature provides a very sensitive way to characterize the mispointing error of the MWR sensor antenna footprints. This thesis describes the algorithm used for the MWR geolocation calibration. MWR sensor observed boundaries are determined by the absolute maximum Tb slope location. A system of linear equations is produced for each sensor observed land/water crossing to determine the true intersection of the MWR track with the coastline. The observed and expected boundary locations are compared by means of an error distance. Results, presented for all eight beams of the three MWR channels, show that the mispointing error (standard deviations) are overall less than 15 km from the true coastline.
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Date Issued
2012
Identifier
CFE0004245, ucf:49523
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004245
HURRICANE WIND SPEED AND RAIN RATE RETRIEVAL ALGORITHM FOR THE STEPPED FREQUENCY MICROWAVE RADIOMETER
Title
HURRICANE WIND SPEED AND RAIN RATE RETRIEVAL ALGORITHM FOR THE STEPPED FREQUENCY MICROWAVE RADIOMETER.
Creator
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.
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Date Issued
2006
Identifier
CFE0001313, ucf:47024
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001313
An Emissive Antenna Correction for The Tropical Rainfall Measuring Mission Microwave Imager (TMI)
Title
An Emissive Antenna Correction for The Tropical Rainfall Measuring Mission Microwave Imager (TMI).
Creator
Alquaied, Faisal, Jones, W Linwood, Mikhael, Wasfy, Wei, Lei, Zec, Josko, Wilheit, Thomas, University of Central Florida
Abstract / Description
This dissertation deals with the radiometric calibration of a satellite microwave radiometer known as the TRMM Microwave Imager (TMI), which operated on NASA's Tropical Rainfall Measuring Mission (TRMM). This multi-frequency, conical-scanning, passive microwave, remote sensor measures the earth's blackbody emissions (brightness temperature, Tb) from a low earth orbit and covers the tropics ((&)#177;35(&)deg; latitude). The original scientific objective for TRMM's 3-year mission was to measure...
Show moreThis dissertation deals with the radiometric calibration of a satellite microwave radiometer known as the TRMM Microwave Imager (TMI), which operated on NASA's Tropical Rainfall Measuring Mission (TRMM). This multi-frequency, conical-scanning, passive microwave, remote sensor measures the earth's blackbody emissions (brightness temperature, Tb) from a low earth orbit and covers the tropics ((&)#177;35(&)deg; latitude). The original scientific objective for TRMM's 3-year mission was to measure the statistics of rainfall in the tropics. However, the mission was quite successful, and TRMM was extended for greater than 17 years to provide a long-term satellite rain measurements, which has contributed significantly to the study of global climate change.A significant part of the extended TRMM mission was the establishment of a constellation of satellite radiometer that provide frequent global rainfall measurements that enable severe storm warnings for operational hazard forecast by the international weather community. TRMM played a key role by serving as the radiometric calibration standard for the TRMM constellation microwave radiometers.The objective of this dissertation is to improve the radiometric calibration of TMI and to provide to NASA a new robust, physics-based algorithm for the legacy data processing of the TRMM brightness temperature data product, which will be called TMI 1B11 V8. Moreover, the results of this new procedure have been validated using the double difference techniques with the Global Precipitation Mission Microwave Imager (GMI), which is the replacement satellite mission to TRMM.
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Date Issued
2017
Identifier
CFE0006711, ucf:51900
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006711
Hurricane Imaging Radiometer (HIRAD) tropical rainfall retrievals
Title
Hurricane Imaging Radiometer (HIRAD) tropical rainfall retrievals.
Creator
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.
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Date Issued
2019
Identifier
CFE0007775, ucf:52379
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007775
Brightness Temperature Calibration of SAC-D/Aquarius Microwave Radiometer (MWR)
Title
Brightness Temperature Calibration of SAC-D/Aquarius Microwave Radiometer (MWR).
Creator
Biswas, Sayak, Jones, W, Georgiopoulos, Michael, Wahid, Parveen, Wilheit, Thomas, University of Central Florida
Abstract / Description
The Aquarius/SAC-D joint international science mission, between the NationalAeronautics and Space Administration (NASA) of United States and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE), was launched on a polar-orbiting satellite on June 10, 2011. This mission of discovery will provide measurements of the global sea surface salinity, which contributes to understanding climatic changes in the global water cycle and how these variations inuence the general...
Show moreThe Aquarius/SAC-D joint international science mission, between the NationalAeronautics and Space Administration (NASA) of United States and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE), was launched on a polar-orbiting satellite on June 10, 2011. This mission of discovery will provide measurements of the global sea surface salinity, which contributes to understanding climatic changes in the global water cycle and how these variations inuence the general ocean circulation. The Microwave Radiometer (MWR), a three channel Dicke radiometer operating at 23.8 GHz H-Pol and 36.5 GHz V-(&) H-Pol provided by CONAE, will complement Aquarius (NASA's L-band radiometer/scatterometer) by providing simultaneous spatially collocated environmental measurements such as water vapor, cloud liquid water, surface wind speed, rain rate and sea ice concentration.This dissertation focuses on the overall radiometric calibration of MWR instrument.Which means establishing a transfer function that relates the instrument output to the antenna brightness temperature (Tb). To achieve this goal, the dissertation describes a microwave radiative transfer model of the instrument and validates it using the laboratory and thermal-vacuum test data. This involves estimation of the losses and physical temperature profile in the path from the receiver to each antenna feed-horn for all the receivers. As the pre-launch laboratory tests can only provide a simulated environment which is very different from the operational environment in space, an on-orbit calibration of the instrument is very important. Inter-satellite radiometric cross-calibration of MWR using the Naval Research Laboratory's multi-frequency polarimetric microwave radiometer, WindSat, on board the Coriolis satellite is also an important part of this dissertation. Cross-calibration between two different satellite instruments require normalization of Tb's to account for the frequency and incidence angle dierence between the instruments. Also inter-satellite calibration helps to determine accurate antenna pattern correction coefficients and other small instrument biases.
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Date Issued
2012
Identifier
CFE0004200, ucf:49033
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004200
INTER-SATELLITE MICROWAVE RADIOMETER CALIBRATION
Title
INTER-SATELLITE MICROWAVE RADIOMETER CALIBRATION.
Creator
Hong, Liang, Jones, W. Linwood, University of Central Florida
Abstract / Description
The removal of systematic brightness temperature (Tb) biases is necessary when producing decadal passive microwave data sets for weather and climate research. It is crucial to achieve Tb measurement consistency among all satellites in a constellation as well as to maintain sustained calibration accuracy over the lifetime of each satellite sensor. In-orbit inter-satellite radiometric calibration techniques provide a long term, group-wise solution; however, since radiometers operate at...
Show moreThe removal of systematic brightness temperature (Tb) biases is necessary when producing decadal passive microwave data sets for weather and climate research. It is crucial to achieve Tb measurement consistency among all satellites in a constellation as well as to maintain sustained calibration accuracy over the lifetime of each satellite sensor. In-orbit inter-satellite radiometric calibration techniques provide a long term, group-wise solution; however, since radiometers operate at different frequencies and viewing angles, Tb normalizations are made before making intermediate comparisons of their near-simultaneous measurements. In this dissertation, a new approach is investigated to perform these normalizations from one satellite's measurements to another. It uses Taylor's series expansion around a source frequency to predict Tb of a desired frequency. The relationship between Tb's and frequencies are derived from simulations using an oceanic Radiative Transfer Model (RTM) over a wide variety of environmental conditions. The original RTM is built on oceanic radiative transfer theory. Refinements are made to the model by modifying and tuning algorithms for calculating sea surface emission, atmospheric emission and attenuations. Validations were performed with collocated WindSat measurements. This radiometric calibration approach is applied to establish an absolute brightness temperature reference using near-simultaneous pair-wise comparisons between a non-sun synchronous radiometer and two sun-synchronous polar-orbiting radiometers: the Tropical Rain Measurement Mission (TRMM) Microwave Imager (TMI), WindSat (on Coriolis) and Advanced Microwave Scanning Radiometer (AMSR) on Advanced Earth Observing System –II (ADEOSII), respectively. Collocated measurements between WindSat and TMI as well as between AMSR and TMI, within selected 10 weeks in 2003 for each pair, are collected, filtered and applied in the cross calibration. AMSR is calibrated to WindSat using TMI as a transfer standard. Accuracy prediction and error source analysis are discussed along with calibration results. This inter-satellite radiometric calibration approach provides technical support for NASA's Global Precipitation Mission which relies on a constellation of cooperative satellites with a variety of microwave radiometers to make global rainfall measurements.
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Date Issued
2008
Identifier
CFE0002003, ucf:47626
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002003
RAIN RATE ALGORITHM FOR AQUARIUS/SAC-D MICROWAVE RADIOMETER
Title
RAIN RATE ALGORITHM FOR AQUARIUS/SAC-D MICROWAVE RADIOMETER.
Creator
Menzerotolo, Rosa, Jones, W. Linwood, University of Central Florida
Abstract / Description
Microwave radiometers are used to measure blackbody microwave emissions emitted by natural targets. Radiative transfer theory provides a well founded physical relationship between the atmosphere and surface geophysical parameters and the brightness temperature measured by these radiometers. The atmospheric brightness temperature is proportional to the integral of the microwave absorption of water vapor, oxygen, and liquid water between the top of the atmosphere and the surface. Inverse...
Show moreMicrowave radiometers are used to measure blackbody microwave emissions emitted by natural targets. Radiative transfer theory provides a well founded physical relationship between the atmosphere and surface geophysical parameters and the brightness temperature measured by these radiometers. The atmospheric brightness temperature is proportional to the integral of the microwave absorption of water vapor, oxygen, and liquid water between the top of the atmosphere and the surface. Inverse radiative transfer models use to retrieve the water vapor, cloud liquid and oxygen content in the atmosphere are very well known; however, the retrieval of rain rate in the atmosphere is still a challenge. This project presents a theoretical basis for the rain rate retrieval algorithm, which will be implemented in the Aquarius/SAC-D Microwave Radiometer (MWR). This algorithm was developed based on the radiative transfer model theory for a single layer atmosphere using four WindSat channels. Transmissivity due to liquid water (rain and cloud liquid water) is retrieved from the four channel brightness temperatures, and a statistical regression is performed to relate the rain rate, rain physical temperature and rain height to the liquid water transmissivities at 24 GHz and 37 GHz. Empirical validation results are presented using the WindSat radiometer observations.
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Date Issued
2011
Identifier
CFE0003571, ucf:48911
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003571
On-orbit Inter-satellite Radiometric Calibration of Cross-track Scanning Microwave Radiometers
Title
On-orbit Inter-satellite Radiometric Calibration of Cross-track Scanning Microwave Radiometers.
Creator
Ebrahimi, Hamideh, Jones, W Linwood, Mikhael, Wasfy, Wahid, Parveen, Wang, James, Wilheit, Thomas, University of Central Florida
Abstract / Description
This dissertation concerns the development of an improved algorithm for the inter-satellite radiometric calibration (XCAL) for cross track scanning microwave radiometers in support of NASA's Global Precipitation Mission (GPM). This research extends previous XCAL work to assess the robustness of the CFRSL (")double difference(") technique for sounder X-CAL. In this work, using a two-year of observations, we present a statistical analysis of radiometric biases performed over time and viewing...
Show moreThis dissertation concerns the development of an improved algorithm for the inter-satellite radiometric calibration (XCAL) for cross track scanning microwave radiometers in support of NASA's Global Precipitation Mission (GPM). This research extends previous XCAL work to assess the robustness of the CFRSL (")double difference(") technique for sounder X-CAL. In this work, using a two-year of observations, we present a statistical analysis of radiometric biases performed over time and viewing geometry. In theory, it is possible to apply the same X-CAL procedure developed for conical-scanning radiometers to cross-track scanners; however the implementation is generally more tedious. For example, with the cross-track scan angle, there is a strong response in the observed Tb due to changes in the atmosphere slant path and surface emissivity with the Earth incidence angle. For ocean scenes this is trivial; however for land scenes there is imperfect knowledge of polarized emissivity. However, for the sounder channels the surface emissivity is not the dominant component of top-of-the-atmosphere Tb, which is a mitigating factor. Also, cross-track scanners introduce changes in the radiometer antenna observed polarization with scan angle. The resulting observation is a mixture of un-polarized atmospheric emissions and vertical and horizontal polarized surface emissions. The degree of polarization mixing is known from geometry; however, reasonable estimates of the surface emissivity are required, which complicate over land comparisons. Finally, the IFOV size monotonically increases over the cross-track scan. Thus, when inter-comparing cross-track scanning radiometers, it will be necessary to carefully consider these effects when performing the double difference procedure.
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Date Issued
2016
Identifier
CFE0006453, ucf:51411
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006453
CONAE MicroWave Radiometer (MWR) Counts to Brightness Temperature Algorithm
Title
CONAE MicroWave Radiometer (MWR) Counts to Brightness Temperature Algorithm.
Creator
Ghazi, Zoubair, Jones, W Linwood, Wei, Lei, Mikhael, Wasfy, Wu, Thomas, Junek, William, Piepmeier, Jeffrey, University of Central Florida
Abstract / Description
This dissertation concerns the development of the MicroWave Radiometer (MWR) brightness temperature (Tb) algorithm and the associated algorithm validation using on-orbit MWR Tb measurements. This research is sponsored by the NASA Earth Sciences Aquarius Mission, a joint international science mission, between NASA and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE). The MWR is a CONAE developed passive microwave instrument operating at 23.8 GHz (K-band) H-pol...
Show moreThis dissertation concerns the development of the MicroWave Radiometer (MWR) brightness temperature (Tb) algorithm and the associated algorithm validation using on-orbit MWR Tb measurements. This research is sponsored by the NASA Earth Sciences Aquarius Mission, a joint international science mission, between NASA and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE). The MWR is a CONAE developed passive microwave instrument operating at 23.8 GHz (K-band) H-pol and 36.5 GHz (Ka-band) H- (&) V-pol designed to complement the Aquarius L-band radiometer/scatterometer, which is the prime sensor for measuring sea surface salinity (SSS). MWR measures the Earth's brightness temperature and retrieves simultaneous, spatially collocated, environmental measurements (surface wind speed, rain rate, water vapor, and sea ice concentration) to assist in the measurement of SSS.This dissertation research addressed several areas including development of: 1) a signal processing procedure for determining and correcting radiometer system non-linearity; 2) an empirical method to retrieve switch matrix loss coefficients during thermal-vacuum (T/V) radiometric calibration test; and 3) an antenna pattern correction (APC) algorithm using Inter-satellite radiometric cross-calibration of MWR with the WindSat satellite radiometer. The validation of the MWR counts-to-Tb algorithm was performed using two years of on-orbit data, which included special deep space calibration measurements and routine clear sky ocean/land measurements.
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Date Issued
2014
Identifier
CFE0005496, ucf:50366
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005496
AN IMPROVED MICROWAVE RADIATIVE TRANSFER MODEL FOR OCEAN EMISSIVITY AT HURRICANE FORCE SURFACE WIND SPEED
Title
AN IMPROVED MICROWAVE RADIATIVE TRANSFER MODEL FOR OCEAN EMISSIVITY AT HURRICANE FORCE SURFACE WIND SPEED.
Creator
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.
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Date Issued
2006
Identifier
CFE0001312, ucf:47019
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001312
AN OCEAN SURFACE WIND VECTOR MODEL FUNCTION FOR A SPACEBORNE MICROWAVE RADIOMETER AND ITS APPLICATION
Title
AN OCEAN SURFACE WIND VECTOR MODEL FUNCTION FOR A SPACEBORNE MICROWAVE RADIOMETER AND ITS APPLICATION.
Creator
Soisuvarn, Seubson, Jones, W. Linwood, University of Central Florida
Abstract / Description
Ocean surface wind vectors over the ocean present vital information for scientists and forecasters in their attempt to understand the Earth's global weather and climate. As the demand for global wind velocity information has increased, the number of satellite missions that carry wind-measuring sensors has also increased; however, there are still not sufficient numbers of instruments in orbit today to fulfill the need for operational meteorological and scientific wind vector data. Over the...
Show moreOcean surface wind vectors over the ocean present vital information for scientists and forecasters in their attempt to understand the Earth's global weather and climate. As the demand for global wind velocity information has increased, the number of satellite missions that carry wind-measuring sensors has also increased; however, there are still not sufficient numbers of instruments in orbit today to fulfill the need for operational meteorological and scientific wind vector data. Over the last three decades operational measurements of global ocean wind speeds have been obtained from passive microwave radiometers. Also, vector ocean surface wind data were primarily obtained from several scatterometry missions that have flown since the early 1990's. However, other than SeaSat-A in 1978, there has not been combined active and passive wind measurements on the same satellite until the launch of the second Advanced Earth Observing Satellite (ADEOS-II) in 2002. This mission has provided a unique data set of coincident measurements between the SeaWinds scatterometer and the Advanced Microwave Scanning Radiometer (AMSR). AMSR observes the vertical and horizontal brightness temperature (TB) at six frequency bands between 6.9 GHz and 89.0 GHz. Although these measurements contain some wind direction information, the overlying atmospheric influence can easily obscure this signal and make wind direction retrieval from passive microwave measurements very difficult. However, at radiometer frequencies between 10 and 37 GHz, a certain linear combination of vertical and horizontal brightness temperatures causes the atmospheric dependence to be nearly cancelled and surface parameters such as wind speed, wind direction and sea surface temperature to dominate the resulting signal. This brightness temperature combination may be expressed as ATBV-TBH, where A is a constant to be determined and the TBV and TBH are the brightness temperatures for the vertical and horizontal polarization respectively. In this dissertation, an empirical relationship between the AMSR's ATBV-TBH and SeaWinds' surface wind vector retrievals was established for three microwave frequencies: 10, 18 and 37 GHz. This newly developed model function for a passive microwave radiometer could provide the basis for wind vector retrievals either separately or in combination with scatterometer measurements.
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Date Issued
2006
Identifier
CFE0001493, ucf:47088
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001493
SIMULATION OF BRIGHTNESS TEMPERATURES FOR THE MICROWAVE RADIOMETER ON THE AQUARIUS/SAC-D MISSION.
Title
SIMULATION OF BRIGHTNESS TEMPERATURES FOR THE MICROWAVE RADIOMETER ON THE AQUARIUS/SAC-D MISSION.
Creator
Khan, Salman, Jones, W. Linwood, University of Central Florida
Abstract / Description
Microwave radiometers are highly sensitive receivers capable of measuring low levels of natural blackbody microwave emissions. Remote sensing by satellite microwave radiometers flying on low-earth, polar orbiting, satellites can infer a variety of terrestrial and atmospheric geophysical parameters for scientific and operational applications, such as weather and climate prediction. The objective of this thesis is to provide realistic simulated ocean brightness temperatures for the 3-channel...
Show moreMicrowave radiometers are highly sensitive receivers capable of measuring low levels of natural blackbody microwave emissions. Remote sensing by satellite microwave radiometers flying on low-earth, polar orbiting, satellites can infer a variety of terrestrial and atmospheric geophysical parameters for scientific and operational applications, such as weather and climate prediction. The objective of this thesis is to provide realistic simulated ocean brightness temperatures for the 3-channel Microwave Radiometer (MWR), which will be launched in May 2010 on the joint NASA/CONAE Aquarius/SAC-D Mission. These data will be used for pre-launch geophysical retrieval algorithms development and validation testing. Analyses are performed to evaluate the proposed MWR measurement geometry and verify the requirements for spatial/temporal sampling. Finally, a preliminary study is performed for the post-launch inter-satellite radiometric calibration using the WindSat polarimetric radiometer on the Coriolis satellite.
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Date Issued
2009
Identifier
CFE0002821, ucf:48074
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002821