W. Linwood Jones

University of Central Florida | UCF · Department of Electrical Engineering & Computer Science

The objective of the Hurricane Imaging Radiometer (HIRAD) is to produce wide-swath images of hurricane wind and rain fields during a single pass from a high-altitude aircraft. This instrument could be a prototype for the next generation of airborne hurricane remote sensors that operate on NOAA/USAF surveillance flights over named storms and hurrica...

This paper deals with the validation of rain rate and wind speed measurements from the High-Altitude Wind and Rain Airborne Profiler (HIWRAP), which occurred in September 2013 when the NASA Global Hawk unmanned aerial vehicle passed over an ocean rain squall line in the Gulf of Mexico near the North Florida coast. The three-dimensional atmospheric...

This paper presents the results of the first characterization of coincident Ku- and Ka-band ocean surface normalized radar cross section measurements at earth incidence angles 0°–18° using one year of wide swath Global Precipitation Measurement (GPM) mission dual frequency precipitation radar (DPR) data. Empirical geophysical model functions were d...

In this paper, we demonstrate the feasibility of remote sensing of ocean vector wind (OVW) from the Global Precipitation Measurement (GPM) satellite. By combining its active normalized radar cross section (σ0 ), and passive microwave brightness temperature (Tbs) measurements, ocean surface wind vectors were retrieved and validated by comparison wit...

This paper presents TRMM microwave imager (TMI) main reflector new physical temperatures (Tphy) look-up tables to produce next version of TMI brightness temperature products (GPM V07 Tbs). A modified and improved radiative transfer theory (RTM) based approach was used to determine the new physical temperatures (Tphy) for entire TRMM lifetime. New b...

This article presents a novel ocean vector wind(OVW) retrieval algorithm for remote sensing of ocean winds, using the precipitation radar (PR) and tropical rainfall measurement mission (TRMM) microwave imager (TMI) that operated for >17 years on the TRMM observatory. In this study, the wind speed and anisotropic wind direction (WD) characteristics...

The National Aeronautics and Space Administration’s (NASA) Precipitation Measurement Missions (PMMs) include two earth satellite missions, namely, the Tropical Rainfall Measuring Mission (TRMM, 19972015) and the Global Precipitation Measurement (GPM, 2014present). To generate a consistent multi-decadal brightness temperature (Tb) record that spans...

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 retrieva...

This paper presents a novel ocean vector wind (OVW) retrieval using the Precipitation Radar (PR) anisotropic backscatter signature and the TRMM Microwave Imager (TMI) linearly polarized Tb measurements, both on board of the Tropical Rainfall Measuring Mission (TRMM) satellite. In this paper, the modified 2nd Stokes parameter (weighted difference of...

In this paper, we describe the development of Geophysical Model Functions (GMF) for remote sensing of ocean vector winds using the Precipitation Radar (PR) and TRMM Microwave Imager (TMI) that operated for > 17 years on the Tropical Rainfall Measurement Mission (TRMM) observatory. Wind speed and anisotropic wind direction characteristics of the oce...

When oceanic rainfall occurs, it creates a vertical salinity profile that is fresher at the surface. This freshwater lens is mixed downward by turbulent diffusion, dissipating over a few hours until the upper layer (1–5 m depth) becomes well mixed. Thus, there will be a transient bias between the in situ bulk salinity and the satellite-measured sea...

Conventional satellite intercalibration for microwave imaging radiometers involves a linear two-point calibration approach, over cold ocean scenes and warm ends of the scene brightness temperatures, traditionally over tropical rain forest. Unfortunately, this approach ignores the possibility of non-linear radiometer transfer function, which is ofte...

This paper discusses the intersatellite radiometric calibration for microwave sounders in support of NASA's Global Precipitation Measurement (GPM) mission. This paper is an extension of previous GPM Intersatellite Calibration Working Group work, which assesses the robustness of the Central Florida Remote Sensing Laboratory "double difference" techn...

In this paper, we describe a Monte Carlo technique to simulate the active and passive remote sensor observations (normalized ocean radar backscatter, σ° and brightness temperatures, Tb) and to estimate the resulting wind direction retrieval accuracy. A critical part of the simulation was to calculate the satellite/sensor geometry for each point alo...

Within the microwave remote sensing community, simulations have traditionally been used to estimate the system geophysical parameter measurement performance • This Monte Carlo study is a work-in-progress, and simulations have been performed for only one-day • Nevertheless, preliminary MLE results for WS > 10 m/s are quite encouraging • WD measureme...

This paper describes a novel ocean vector wind (OVW) retrieval algorithm that uses Ku-band Precipitation Radar (PR) and the multi-frequency TRMM Microwave Imager (TMI), both on board the Tropical Rainfall Measuring Mission (TRMM) satellite. The basis of this algorithm is the anisotropic nature of ocean backscatter (sig-0) and brightness temperature...

The National Aeronautics and Space Administration (NASA) has always included data reprocessing as a major component of every science mission. A final reprocessing is typically a part of mission closeout (known as phase F). The Tropical Rainfall Measuring Mission (TRMM) is currently in phase F, and NASA is preparing for the last reprocessing of all...

This paper describes the technical approach to generate homogeneous warm brightness temperature scene binary mask over the earth for the intercalibration of microwave imagers. The objective is to identify homogeneous desert scenes as targets in radiometric intercalibration of multisource multisensor systems such as Global Precipitation Measurement...

The NASA Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) has produced a 17-plus-year time-series of calibrated microwave radiances that have remarkable value for investigating the effects of the Earth's climate change over the tropics. Recently, the Global Precipitation Measurement (GPM) Inter-Satellite Radiometric Calibration (XC...

RapidScat is a National Aeronautics and Space Administration (NASA) Ku-Band scatterometer that was operated onboard the International Space Station between September 2014 and August 2016 when the mission effectively ended after an irrecoverable instrument failure. A unique non-Sun-synchronous orbit facilitated global contiguous geographical samplin...

The Hurricane Imaging Radiometer (HIRAD) is an airborne microwave radiometer developed to provide wide-swath hurricane surface wind speed and rain rate imagery for scientific research. This letter presents a geometric evaluation of the brightness temperature (Tb) images produced by HIRAD for high-contrast land/water targets. Methodologies used to v...

This paper discusses the radiometric calibration of millimeter sounder radiometers, on polar orbiter satellites in the NASA Global Precipitation Mission (GPM) constellation; and presents radiometric bias results. Because the Tropical Rainfall Measurement Mission (TRMM) operated for over 17 years, it is important to combine the TRMM and the GPM prec...

The Tropical Rainfall Measuring Mission (TRMM), launched in late November 1997 into a low earth orbit, produced the longest satellite-derived precipitation time series of 17 years. During the second half of this mission, a collection of cooperative weather satellites, with microwave radiometers, was combined to produce a 6-h tropical precipitation...

The Global Precipitation Measurement (GPM) mission is a constellation-based satellite mission designed to unify and advance precipitation measurements using both research and operational microwave sensors. This requires consistency in the input brightness temperatures (Tb), which is accomplished by intercalibrating the constellation radiometers usi...

A common practice in radiometric inter-calibration of two sensors is to compare the observed brightness temperature (T b) with a simulated T b using a forward radiative transfer model (RTM) and input geophysical parameters. Although comparison of microwave sounders show a good radiometric consistency , when the measurements are used in a numerical...

This paper presents recent results of an investigation into the transient effects of oceanic rainfall on the profile of near-surface salinity. Based upon research conducted with the NASA/CONAE Aquarius/SAC-D mission, it was determined that the primary rain impact was to dilute the sea surface salinity (SSS), which was accurately captured by the Aqu...

Satellite precipitation measurements began a new era with the commissioning of the new Global Precipitation Measurements Microwave Imager (GMI) in March 2014. For the previous 17 years, the Tropical Rainfall Measurements Mission (TRMM) Microwave Imager (TMI), operating in a non-sun-synchronous orbit, served as the radiometric transfer standard for...

A robust XCAL double difference (DD) approach for radiometric calibration has been successfully applied between the TRMM Microwave Imager, TMI, (previous calibration transfer standard for NASA's Precipitation Measuring Mission) and a number of precipitation measuring radiometers in polar sun-synchronous orbits. Now that the TRMM Mission has ended (...

The Argentinian Itenerant Tower Radiometer (RATI from its spanish acronym) its an L Band polarimetric radiometer developed by the IAFE Remote Sensing Group and CFRLS (Florida, US). It was designed to calibrate and validate radiometric satellite observations and remote sensing products. In this work, instrument main characteristics and the thermal c...

By its end of mission in 2015, the Tropical Rainfall Measuring Mission (TRMM) far exceeded its three-year design life, providing over 17 years of invaluable Earth observations. This paper details how a previously undiscovered source of calibration error for the TRMM Microwave Imager (TMI) has been recently detected and how a simple mitigation techn...

Earth observing satellite microwave radiometers have been in use since the 1960's providing geoscientists invaluable insight into the complex interaction of the atmosphere, ocean and land in the climate of our planet. Such key instruments must be vetted of any calibration issues so as to provide the utmost accurate and stabilized dataset for scient...

The newest innovation to passive microwave remote sensing technology is the inclusion of noise diodes for radiometric calibration of total power radiometers. Instead of the usual two-point calibration using passive black body sources, now there are four-calibration noise levels, which allow system nonlinearities to be corrected. Conventional approa...

Remote sensing of salinity using satellite-mounted microwave radiometers provides new perspectives for studying ocean dynamics and the global hydrological cycle. Calibration and validation of these measurements is challenging because satellite and in situ methods measure salinity differently. Microwave radiometers measure the salinity in the top fe...

This paper provides the description of an ocean wind speed retrieval algorithm developed for the SAC-D/Aquarius microwave radiometer’s (MWR). Empirical model coefficients are derived using MWR brightness temperature at 36.5 GHz H- and V-pol with collocated numerical weather prediction (NWP) model estimates of oceanic and atmospheric environmental p...

Aquarius (AQ)/SAC-D is a joint National Aeronautics and Space Administration (NASA)/Comisión Nacional de Actividades Espaciales (CONAE; Argentine Space Agency) Earth Sciences satellite mission to measure global sea surface salinity (SSS), using a L-band radiometer/scatterometer that measures ocean brightness temperature (Tb) and radar backscatter (...

http://www.nap.edu/catalog/21729/a-strategy-for-active-remote-sensing-amid-increased-demand-for-radio-spectrum

The effect of rain on surface salinity stratification is analyzed to develop a rain roughness correction scheme to reduce the uncertainty of Aquarius sea surface salinity (SSS) retrieved under rainy conditions. Rain freshwater inputs may cause large discrepancies in salinity measured by Aquarius at 1–2 cm within the surface and the calibration refe...

The Aquarius/SAC-D, International Earth Science Satellite Mission, is a collaboration between NASA and the Argentine Space Agency (Comision Nacional de Actividades Espaciales, CONAE) that was launched on June 10, 2011 to provide scientists with monthly global maps of sea surface salinity (SSS) to understand the Earth’s hydrological cycle and to inv...

The microwave radiometer (MWR) is a Dicke radiometer on board of the Aquarius (AQ)/SAC-D satellite. It was developed by Argentine space agency, Comisión Nacional De Actividades Espaciales (CONAE), and operates at 23.8 and 36.5 GHz frequencies. After MWR initially turned on, the first brightness temperature ([Formula: see text]) measurements were ob...

NASA's Global Hawk aircraft (AV1)has two microwave sensors: the passive Hurricane Imaging Radiometer (HIRAD), and the active High-altitude Imaging Wind and Rain Airborne Profiler(HIWRAP). Results are presented for a rain measurement validation opportunity that occurred in 2013, when the AV1 flew over a tropical squall-line that was simultaneously o...

The European Space Agency’s soil moisture ocean salinity (SMOS) satellite was launched in 2009 to measure land soil moisture and sea surface salinity (SSS). It carries an L-band microwave imaging radiometer that measures brightness temperatures that are used to produce global ocean salinity (OS) maps every three days. Similar maps are obtained with...

At RF/microwave frequencies below 10 GHz, the atmosphere is considered transparent except for cases of extreme rain events. Moreover, scattering effects from rain drops are generally negligible, and the calculations of extinction coefficients are primarily liquid water absorption. In convective rain events (thunderstorms), larger rain drop sizes wo...

The first step in radiometric inter-calibration is to ascertain the self-consistency and reasonableness of the observed brightness temperature (Tb) for each individual sensor involved. One of the widely used approaches is to compare the observed Tb with a simulated Tb using a forward radiative transfer model (RTM) and input geophysical parameters a...