Steven Reising | Colorado State University (original) (raw)

Papers by Steven Reising

This paper presents a model of the Stokes vector emission from the ocean surface. The ocean surfa... more This paper presents a model of the Stokes vector emission from the ocean surface. The ocean surface is described as an ensemble of facets with Cox and Munk's Gram-Charlier slope distribution. The study discusses the impact of different up-wind and cross-wind rms slopes, skewness, peakedness, foam cover models and atmospheric effects on the azimuthal variation of the Stokes vector, as well as the limitations of the model. Simulation results compare favorably, both in mean value and azimuthal dependence, with SSWI data at 53" incidence angle and with JPL's WINDRAD measurements at incidence angles from 30" to 65", and at wind speeds from 2.5 to 11 d s . "

In the past few years, dramatic experimental evidence has emerged, showing that tropospheric ligh... more In the past few years, dramatic experimental evidence has emerged, showing that tropospheric lightning discharges modify the mesosphere and the lower ionosphere through heating and ionization, producing gamma-ray bursts and optical emissions known as red sprites, blue jets, and elves. These transient electrodynamic coupling processes may have long-term effects such as chemical changes, persistent heating of ionospheric electrons, and increased production of mesospheric and stratospheric nitrogen oxides (NO y ). In order to assess the regional and global effects of the intense electrodynamic coupling of thunderstorms to the middle atmosphere, the occurrence rate of Sprites needs to be known over large areas of the Earth. Since continuous optical monitoring of Sprite occurrence on large spatial scales is not practical, a continuous proxy indicator for Sprite occurrence is needed.

This paper describes the deployment of a fully polarimetric K-band radiometer in the Rough Evapor... more This paper describes the deployment of a fully polarimetric K-band radiometer in the Rough Evaporation Duct (RED) experiment, which was conducted during August and September of 2001. The calibration of the four Stokes parameters is described, along with a comparison of the measurements with results of both the Klein-Swift and Ellison et al. sea surface dielectric models. The purpose of the experiment was to improve physical forward models of the ocean surface emission in order to improve wind vector retrieval algorithms. 0-7803-7930-6/$17.00 (C) 2003 IEEE

Expanding concentric rings of gravity waves were observed on the night of 11 May 2004 by the all-... more Expanding concentric rings of gravity waves were observed on the night of 11 May 2004 by the all-sky OH imager at Yucca Ridge Field Station (40.7°N, 104.9°W) near Fort Collins, Colorado. The pattern was observed for about 1.5 hours, with the rings encompassing nearly 360° for the first 30 minutes. The centers of the rings were observed at the geographic locations of two convective plumes. We measure the horizontal wavelengths and periods of these gravity waves as functions of both radius and observation time. The observations compare favorably with predictions from a ray-tracing program using the internal gravity wave dispersion relation with assumed zero wind. Since all the 5 events of concentric patterns among 760 nights of image were observed in May or late August/early September, we hypothesize that the weak mean background zonal wind near equinoxes is a necessary condition for gravity waves excited from convective overshoots near the tropopause to be observed as concentric ring...

WindSat, the first polarimetric microwave radiometer on orbit, and the NPOESS Conical Microwave I... more WindSat, the first polarimetric microwave radiometer on orbit, and the NPOESS Conical Microwave Imager/Sounder,

Successful naval operations require excellent knowledge of the ocean wind speed and direction. In... more Successful naval operations require excellent knowledge of the ocean wind speed and direction. In addition, the global ocean wind vector is a key element for weather forecasting and for climate and oceanography studies. WindSat, a satellite-borne multifrequency polarimetric microwave radiometer developed by the Naval Research Laboratory, has demonstrated the ability to remotely sense the global ocean wind vector from space.1 The wind direction signal measured by WindSat is about two orders of magnitude smaller than the background scene, and only a little larger than the radiometer noise floor. Therefore, any small uncertainties in the geophysical model used to retrieve the wind direction will introduce errors in the retrieved wind vector. One such uncertainty is the contribution of sea foam on the wind direction signal. Down-looking radiometers, such as WindSat, receive energy emitted from the ocean surface and the atmosphere. The energy from the ocean surface, quantified as the bri...

Quantitative precipitation forecasting is limited by the paucity of observations of water vapor i... more Quantitative precipitation forecasting is limited by the paucity of observations of water vapor in the troposphere. In particular, severe storms have been observed to develop in regions of strong and rapidly evolving moisture gradients. Conventional measurements of water vapor density profiles are obtained using in-situ probes on-board weather balloons, including radiosondes. These in-situ profile measurements have high vertical resolution, but have severe limitations in both temporal and spatial sampling. Lidars use differential absorption techniques to estimate water vapor with comparable resolution to that of radiosonde observations. However, lidars are expensive, and their operation is limited to clear-sky conditions due to the high opacity of clouds at optical wavelengths. Inversion of brightness temperatures measured by upward- looking, ground-based microwave radiometers allows the estimation of vertical profiles with high temporal resolution in both clear and cloudy condition...

Critical microwave component and receiver technologies are under development to reduce the risk, ... more Critical microwave component and receiver technologies are under development to reduce the risk, cost, volume, mass, and development time for a high-frequency microwave radiometer needed to enable wet-tropospheric correction in the coastal zone and over land as part of the NRC Decadal Survey-recommended Surface Water and Ocean Topography (SWOT) Mission. Current satellite ocean altimeters include a nadir-viewing, co-located 18-37 GHz multi-channel microwave radiometer to measure wet-tropospheric path delay. However, due to the area of the instantaneous fields of view on the surface at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. Addition of higher-frequency microwave channels to the Jason-class radiometers on the recommended SWOT mission will improve retrievals in coastal regions and enable retrievals over land. Specifically, high-frequency window channels at 92, 130 and 166 GHz are optimum for wet path delay retriev...

Currently, wet-tropospheric path delay measurements over inland water and coastal areas are extre... more Currently, wet-tropospheric path delay measurements over inland water and coastal areas are extremely sparse. They are generally limited to twice-per-day radiosonde launches and a small number of ground-based GPS or radiometer path delay measurements, as well as radar measurements of phase delay to a small number of fixed targets on the ground. Knowledge of the wet-tropospheric path delay is necessary for next-generation high-resolution altimeters, such as the Surface Water and Ocean Topography (SWOT) mission, in formulation and planned for launch in 2020. SWOT has two major science objectives. First, the oceanographic objective is to characterize ocean mesoscale and sub-mesoscale circulation with horizontal resolution of 10 km and order of 1 cm height precision. Second, the hydrological objective is to provide global height measurements of inland surface water bodies with area of greater than 250 square meters and flow rate of rivers with width greater than 100 m. Wet-tropospheric ...

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015

ABSTRACT Atmospheric profiles of water vapor and temperature can be estimated using appropriate r... more ABSTRACT Atmospheric profiles of water vapor and temperature can be estimated using appropriate retrieval algorithms based on radiometric measurements and atmospheric statistics. Radiometric measurements at multiple frequencies contribute information to profile retrieval, although at some frequencies the information they provide can be highly correlated with that at other frequencies due to similar sensitivities to changes in atmospheric pressure, temperature, and water vapor mixing ratio as a function of altitude. The goal for profile retrieval is to obtain as many independent measurements as possible, both to maximize the vertical resolution and to minimize the retrieval error of the profile. The goal of this study is to determine sets of frequencies in the range from 10 to 200 GHz that provide the largest amount of mutually independent information on water vapor and temperature profiles from ground and airborne instruments for clear sky measurements. Results of such a study are important and useful for frequency selection and design of microwave and millimeter-wave radiometers for humidity and temperature profiling. A branch and bound feature selection algorithm has been used to determine sets of frequencies between 10 and 200 GHz that have the greatest number of degrees of freedom (DOF) for water vapor and temperature retrieval. In general, it has been found that the frequency ranges of 20-23, 85-90, and 165-200 GHz are useful for water vapor profile retrieval, whereas the frequency ranges of 55-65 and 116-120 GHz are useful for temperature profile retrieval. Finally, an analysis has been performed to determine the impact of measurement uncertainty on the number of DOF of measurement and also on the vertical resolution. It was also found that vertical resolution is directly related to the number of DOF.

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015

2012 IEEE/MTT-S International Microwave Symposium Digest, 2012

ABSTRACT The recent introduction of 35-nm gate length InP MMIC low-noise amplifiers has enabled s... more ABSTRACT The recent introduction of 35-nm gate length InP MMIC low-noise amplifiers has enabled significant advances in Earth remote sensing. These low-noise amplifiers achieve 2-dB and 3-dB noise figure at 180 GHz and 90 GHz, respectively, at room temperature. For Earth remote sensing using ocean surface altimeters, the design of new millimeter-wave radiometers is motivated by the fact that these missions include nadir-viewing, co-located 18–37 GHz microwave radiometers to measure wet-tropospheric path delay. However, due to the substantial area of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. In addition, conventional microwave radiometers do not provide wet-path delay over land. For a maximum antenna aperture size on Earth observation satellites, the addition of higher-frequency millimeter-wave (90–170 GHz) radiometers to current Jason-class radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to increase the potential for over-land retrievals.

ABSTRACT Tropospheric water vapor plays a key role in the prediction of convective storm initiati... more ABSTRACT Tropospheric water vapor plays a key role in the prediction of convective storm initiation, precipitation and extreme weather events. Conventionally, water vapor profiles are derived from dewpoint and temperature measurements using instrumented weather balloons, including radiosondes. These balloons take approximately one hour to measure from surface to tropopause, and transmitter-sensor packages cannot be reused. Such in-situ measurements provide profiles with very high vertical resolution but with severe limitations in temporal and spatial coverage. Raman lidars use active optical techniques to provide comparable vertical resolution and measurement accuracy to radiosondes. However, these lidars are bulky and expensive, and their operation is limited to clear-sky conditions due to the high optical opacity of clouds. Microwave radiometers provide path-integrated water vapor and liquid water with high temporal resolution during nearly all weather conditions. If multiple frequencies are measured near the water vapor resonance, coarse vertical profiles can be obtained using statistical inversion. Motivated by the need for improved temporal and spatial resolutions, a network of elevation and azimuth scanning radiometers is being developed to provide coordinated volumetric measurements of tropospheric water vapor. To realize this network, two Miniaturized Water Vapor profiling Radiometers (MVWR) have been designed and fabricated at Colorado State University. MWVR is small, light-weight, consumes little power and is highly stable. To reduce the mass, volume, cost and power consumption as compared to traditional waveguide techniques, MWVR was designed based on monolithic microwave integrated-circuit technology developed for the wireless communication and defense industries. It was designed for network operation, in which each radiometer will perform a complete volumetric scan within a few minutes, and overlapping scans from multiple sensors will be combined tomographically to retrieve the 3D water vapor field as a function of time. In this paper we report new, collocated measurements from a zenith-looking MWVR and a five-channel Radiometrics profiler during REFRACTT (Refractivity Experiment For H2O Research And Collaborative Operational Technology Transfer) led by NCAR during the summer of 2006.

This paper presents a model of the Stokes vector emission from the ocean surface. The ocean surfa... more This paper presents a model of the Stokes vector emission from the ocean surface. The ocean surface is described as an ensemble of facets with Cox and Munk's Gram-Charlier slope distribution. The study discusses the impact of different up-wind and cross-wind rms slopes, skewness, peakedness, foam cover models and atmospheric effects on the azimuthal variation of the Stokes vector, as well as the limitations of the model. Simulation results compare favorably, both in mean value and azimuthal dependence, with SSWI data at 53" incidence angle and with JPL's WINDRAD measurements at incidence angles from 30" to 65", and at wind speeds from 2.5 to 11 d s . "

In the past few years, dramatic experimental evidence has emerged, showing that tropospheric ligh... more In the past few years, dramatic experimental evidence has emerged, showing that tropospheric lightning discharges modify the mesosphere and the lower ionosphere through heating and ionization, producing gamma-ray bursts and optical emissions known as red sprites, blue jets, and elves. These transient electrodynamic coupling processes may have long-term effects such as chemical changes, persistent heating of ionospheric electrons, and increased production of mesospheric and stratospheric nitrogen oxides (NO y ). In order to assess the regional and global effects of the intense electrodynamic coupling of thunderstorms to the middle atmosphere, the occurrence rate of Sprites needs to be known over large areas of the Earth. Since continuous optical monitoring of Sprite occurrence on large spatial scales is not practical, a continuous proxy indicator for Sprite occurrence is needed.

This paper describes the deployment of a fully polarimetric K-band radiometer in the Rough Evapor... more This paper describes the deployment of a fully polarimetric K-band radiometer in the Rough Evaporation Duct (RED) experiment, which was conducted during August and September of 2001. The calibration of the four Stokes parameters is described, along with a comparison of the measurements with results of both the Klein-Swift and Ellison et al. sea surface dielectric models. The purpose of the experiment was to improve physical forward models of the ocean surface emission in order to improve wind vector retrieval algorithms. 0-7803-7930-6/$17.00 (C) 2003 IEEE

Expanding concentric rings of gravity waves were observed on the night of 11 May 2004 by the all-... more Expanding concentric rings of gravity waves were observed on the night of 11 May 2004 by the all-sky OH imager at Yucca Ridge Field Station (40.7°N, 104.9°W) near Fort Collins, Colorado. The pattern was observed for about 1.5 hours, with the rings encompassing nearly 360° for the first 30 minutes. The centers of the rings were observed at the geographic locations of two convective plumes. We measure the horizontal wavelengths and periods of these gravity waves as functions of both radius and observation time. The observations compare favorably with predictions from a ray-tracing program using the internal gravity wave dispersion relation with assumed zero wind. Since all the 5 events of concentric patterns among 760 nights of image were observed in May or late August/early September, we hypothesize that the weak mean background zonal wind near equinoxes is a necessary condition for gravity waves excited from convective overshoots near the tropopause to be observed as concentric ring...

WindSat, the first polarimetric microwave radiometer on orbit, and the NPOESS Conical Microwave I... more WindSat, the first polarimetric microwave radiometer on orbit, and the NPOESS Conical Microwave Imager/Sounder,

Successful naval operations require excellent knowledge of the ocean wind speed and direction. In... more Successful naval operations require excellent knowledge of the ocean wind speed and direction. In addition, the global ocean wind vector is a key element for weather forecasting and for climate and oceanography studies. WindSat, a satellite-borne multifrequency polarimetric microwave radiometer developed by the Naval Research Laboratory, has demonstrated the ability to remotely sense the global ocean wind vector from space.1 The wind direction signal measured by WindSat is about two orders of magnitude smaller than the background scene, and only a little larger than the radiometer noise floor. Therefore, any small uncertainties in the geophysical model used to retrieve the wind direction will introduce errors in the retrieved wind vector. One such uncertainty is the contribution of sea foam on the wind direction signal. Down-looking radiometers, such as WindSat, receive energy emitted from the ocean surface and the atmosphere. The energy from the ocean surface, quantified as the bri...

Quantitative precipitation forecasting is limited by the paucity of observations of water vapor i... more Quantitative precipitation forecasting is limited by the paucity of observations of water vapor in the troposphere. In particular, severe storms have been observed to develop in regions of strong and rapidly evolving moisture gradients. Conventional measurements of water vapor density profiles are obtained using in-situ probes on-board weather balloons, including radiosondes. These in-situ profile measurements have high vertical resolution, but have severe limitations in both temporal and spatial sampling. Lidars use differential absorption techniques to estimate water vapor with comparable resolution to that of radiosonde observations. However, lidars are expensive, and their operation is limited to clear-sky conditions due to the high opacity of clouds at optical wavelengths. Inversion of brightness temperatures measured by upward- looking, ground-based microwave radiometers allows the estimation of vertical profiles with high temporal resolution in both clear and cloudy condition...

Critical microwave component and receiver technologies are under development to reduce the risk, ... more Critical microwave component and receiver technologies are under development to reduce the risk, cost, volume, mass, and development time for a high-frequency microwave radiometer needed to enable wet-tropospheric correction in the coastal zone and over land as part of the NRC Decadal Survey-recommended Surface Water and Ocean Topography (SWOT) Mission. Current satellite ocean altimeters include a nadir-viewing, co-located 18-37 GHz multi-channel microwave radiometer to measure wet-tropospheric path delay. However, due to the area of the instantaneous fields of view on the surface at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. Addition of higher-frequency microwave channels to the Jason-class radiometers on the recommended SWOT mission will improve retrievals in coastal regions and enable retrievals over land. Specifically, high-frequency window channels at 92, 130 and 166 GHz are optimum for wet path delay retriev...

Currently, wet-tropospheric path delay measurements over inland water and coastal areas are extre... more Currently, wet-tropospheric path delay measurements over inland water and coastal areas are extremely sparse. They are generally limited to twice-per-day radiosonde launches and a small number of ground-based GPS or radiometer path delay measurements, as well as radar measurements of phase delay to a small number of fixed targets on the ground. Knowledge of the wet-tropospheric path delay is necessary for next-generation high-resolution altimeters, such as the Surface Water and Ocean Topography (SWOT) mission, in formulation and planned for launch in 2020. SWOT has two major science objectives. First, the oceanographic objective is to characterize ocean mesoscale and sub-mesoscale circulation with horizontal resolution of 10 km and order of 1 cm height precision. Second, the hydrological objective is to provide global height measurements of inland surface water bodies with area of greater than 250 square meters and flow rate of rivers with width greater than 100 m. Wet-tropospheric ...

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015

ABSTRACT Atmospheric profiles of water vapor and temperature can be estimated using appropriate r... more ABSTRACT Atmospheric profiles of water vapor and temperature can be estimated using appropriate retrieval algorithms based on radiometric measurements and atmospheric statistics. Radiometric measurements at multiple frequencies contribute information to profile retrieval, although at some frequencies the information they provide can be highly correlated with that at other frequencies due to similar sensitivities to changes in atmospheric pressure, temperature, and water vapor mixing ratio as a function of altitude. The goal for profile retrieval is to obtain as many independent measurements as possible, both to maximize the vertical resolution and to minimize the retrieval error of the profile. The goal of this study is to determine sets of frequencies in the range from 10 to 200 GHz that provide the largest amount of mutually independent information on water vapor and temperature profiles from ground and airborne instruments for clear sky measurements. Results of such a study are important and useful for frequency selection and design of microwave and millimeter-wave radiometers for humidity and temperature profiling. A branch and bound feature selection algorithm has been used to determine sets of frequencies between 10 and 200 GHz that have the greatest number of degrees of freedom (DOF) for water vapor and temperature retrieval. In general, it has been found that the frequency ranges of 20-23, 85-90, and 165-200 GHz are useful for water vapor profile retrieval, whereas the frequency ranges of 55-65 and 116-120 GHz are useful for temperature profile retrieval. Finally, an analysis has been performed to determine the impact of measurement uncertainty on the number of DOF of measurement and also on the vertical resolution. It was also found that vertical resolution is directly related to the number of DOF.

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015

2012 IEEE/MTT-S International Microwave Symposium Digest, 2012

ABSTRACT The recent introduction of 35-nm gate length InP MMIC low-noise amplifiers has enabled s... more ABSTRACT The recent introduction of 35-nm gate length InP MMIC low-noise amplifiers has enabled significant advances in Earth remote sensing. These low-noise amplifiers achieve 2-dB and 3-dB noise figure at 180 GHz and 90 GHz, respectively, at room temperature. For Earth remote sensing using ocean surface altimeters, the design of new millimeter-wave radiometers is motivated by the fact that these missions include nadir-viewing, co-located 18–37 GHz microwave radiometers to measure wet-tropospheric path delay. However, due to the substantial area of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. In addition, conventional microwave radiometers do not provide wet-path delay over land. For a maximum antenna aperture size on Earth observation satellites, the addition of higher-frequency millimeter-wave (90–170 GHz) radiometers to current Jason-class radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to increase the potential for over-land retrievals.

ABSTRACT Tropospheric water vapor plays a key role in the prediction of convective storm initiati... more ABSTRACT Tropospheric water vapor plays a key role in the prediction of convective storm initiation, precipitation and extreme weather events. Conventionally, water vapor profiles are derived from dewpoint and temperature measurements using instrumented weather balloons, including radiosondes. These balloons take approximately one hour to measure from surface to tropopause, and transmitter-sensor packages cannot be reused. Such in-situ measurements provide profiles with very high vertical resolution but with severe limitations in temporal and spatial coverage. Raman lidars use active optical techniques to provide comparable vertical resolution and measurement accuracy to radiosondes. However, these lidars are bulky and expensive, and their operation is limited to clear-sky conditions due to the high optical opacity of clouds. Microwave radiometers provide path-integrated water vapor and liquid water with high temporal resolution during nearly all weather conditions. If multiple frequencies are measured near the water vapor resonance, coarse vertical profiles can be obtained using statistical inversion. Motivated by the need for improved temporal and spatial resolutions, a network of elevation and azimuth scanning radiometers is being developed to provide coordinated volumetric measurements of tropospheric water vapor. To realize this network, two Miniaturized Water Vapor profiling Radiometers (MVWR) have been designed and fabricated at Colorado State University. MWVR is small, light-weight, consumes little power and is highly stable. To reduce the mass, volume, cost and power consumption as compared to traditional waveguide techniques, MWVR was designed based on monolithic microwave integrated-circuit technology developed for the wireless communication and defense industries. It was designed for network operation, in which each radiometer will perform a complete volumetric scan within a few minutes, and overlapping scans from multiple sensors will be combined tomographically to retrieve the 3D water vapor field as a function of time. In this paper we report new, collocated measurements from a zenith-looking MWVR and a five-channel Radiometrics profiler during REFRACTT (Refractivity Experiment For H2O Research And Collaborative Operational Technology Transfer) led by NCAR during the summer of 2006.