Overview of the Conical Microwave Imager/Sounder development for the NPOESS program

Gasster, Samuel D.; Flaming, G.M.

doi:10.1109/igarss.1998.702874

Cited by 11 publications

(4 citation statements)

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“…First, it is widely accepted that the ocean surface spectrum should vary as for large values of ; it is advantageous to remove this dependency through use of the ocean curvature spectrum, defined as Next it is noted that the functions have a dependence on frequency which can be factored out by defining (8) with the resulting functions depending on frequency only through Using these ideas and re-writing the second order change in brightnesses from a flat surface ( ) in terms of yields (9) where (10) (11) and the new functions have no explicit dependence on frequency. Note that the above equation shows that the effect of changes in frequency is simply to modify i.e., to modify the ocean length scale which is weighted by a particular value of assuming that remains constant with changes in frequency.…”

Section: Simplification Of Spm/ssamentioning

confidence: 99%

“…The success of these studies has resulted in plans for a polarimetric radiometer to be included in the NPOESS series of satellites [8]. Analytical and numerical models for the calculation of ocean surface polarimetric thermal emission have also been developed [9]- [13], primarily through application of standard surface scattering approximate methods to calculate surface emissivity using Kirchhoff's law.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of the small slope approximation for ocean polarimetric thermal emission

Johnson

Zhang

1999

IEEE Trans. Geosci. Remote Sensing

110

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Analytical models for ocean surface polarimetric thermal emission based on the small perturbation method (SPM) have shown success in matching brightness temperature azimuthal variations from aircraft based measurements. It has also been shown that use of the small perturbation method for calculation of surface emissivity results in a series in surface slope, not surface height, so that the method remains accurate for large height surface emission even when it fails for the corresponding scattering calculations. This paper presents a detailed analysis of the SPM/small slope approximation (SPM/SSA) for ocean surface polarimetric thermal emission, and investigates the extent to which varying ocean surface length scales contribute to brightness temperature zeroth and second azimuthal harmonics. It is found that ocean waves of lengths both comparable to and much greater than the electromagnetic wavelength can contribute to these harmonics, depending on the extent to which the ocean surface spectral model places asymmetry in these length scales. In addition, the SPM/SSA is approximated for the contributions of both very long and very short ocean length scales compared to the electromagnetic wavelength, and it is found that both long and short wave contributions can be expressed in simple equations involving either standard or modified ocean surface slope variances.Index Terms-Microwave readiometry, passive remote sensing.

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Section: Simplification Of Spm/ssamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical study of the small slope approximation for ocean polarimetric thermal emission

Johnson

Zhang

1999

IEEE Trans. Geosci. Remote Sensing

110

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“…Five instruments are considered in this example, namely: a) an L-band polarimetric radiometer that we call LRADIO, based on the design of NASA's SMAP mission (Entekhabi, 2010); b) an L-band synthetic aperture radar (LSAR), also based on an instrument on the SMAP mission (Entekhabi, 2010); c) an X-band polarimetric radiometer (XRADIO), based on NPOESS/CMIS (Gasster & Flaming, 1998); d) an infrared multispectral radiometer (IR) based on NPOESS/VIIRS (Welsch & Swenson, 2001); e) a hypothetical P-band polarimetric synthetic aperture radar (PSAR), such as the one proposed for BIOMASS (Heliere et al, 2009). The characteristics (mass, power, data rate, performance) that we assumed for these instruments are provided in the Appendix.…”

Section: Instrument Descriptionmentioning

confidence: 99%

A rule-based method for scalable and traceable evaluation of system architectures

2014

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Despite the development of a variety of decision-aid tools for assessing the value of a conceptual design, humans continue to play a dominant role in this process. Researchers have identified two major challenges to automation, namely the subjectivity of value and the existence of multiple and conflicting customer needs. A third challenge is however arising as the amount of data (e.g., expert judgment, requirements, and engineering models) required to assess value increases. This brings two challenges. First, it becomes harder to modify existing knowledge or add new knowledge into the knowledge base. Second, it becomes harder to trace the results provided by the tool back to the design variables and model parameters. Current tools lack the scalability and traceability required to tackle these knowledge-intensive design evaluation problems. This work proposes a traceable and scalable rule-based architecture evaluation tool called VASSAR that is especially tailored to tackle knowledge-intensive problems that can be formulated as configuration design problems, which is demonstrated using the conceptual design task for a laptop. The methodology has three main steps. First, facts containing the capabilities and performance of different architectures are computed using rules containing physical and logical models. Second, capabilities are compared with requirements to assess satisfaction of each requirement. Third, requirement satisfaction is aggregated to yield a manageable number of metrics. An explanation facility keeps track of the value chain all along this process. This paper describes the methodology in detail, and discusses in particular different implementations of preference functions as logical rules. A full-scale example around the design of Earth observing satellites is presented.

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“…Models for predicting rough surface brightness temperatures are critical for interpreting measurements from ground, air, or space based radiometric systems. Rough surface effects are particularly important in observations of the sea, and remote sensing of sea wind speed and direction is directly related to emission properties of the sea rough surface [24][25][26][27][28][29]. Rough surface effects are also important in remote sensing of soil moisture and sea ice properties.…”

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confidence: 99%

Higher ORDER Emission Model Study of Bi-sinusoidal Surface Brightness Temperatures

Johnson¹

2002

PIER

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Models for microwave thermal emission from a rough surface are currently of interest due to the goal of improved sea surface wind vector retrievals from polarimetric brightness temperature measurements. Models based on either a small slope approximation or on a physical optics approach have been proposed and have shown some success in matching observations. Both of these models involve series solutions, but computation of higher order terms typically is difficult, particularly for multi-scale sea surface models. Knowledge of higher order term contributions, however, would assist in understanding the limitations of the low-order methods applied in practice. In this paper, higher order results from both the small slope and physical optics methods are studied and compared for a simple bi-sinusoidal surface model (i.e. height profile = A sin(2πx Px) sin(2πy Py), where P x and P y are the surface periods in the x and y directions, respectively). Results show both methods to provide good predictions for moderate slope "large scale" surfaces (i.e. periods large compared to the observing electromagnetic wavelength) when shadowing and multiple scattering effects are negligible, while only the small slope theory correctly predicts emission from "small scale" profiles. The influence of both shadowing and multiple scattering effects is examined, and the "binary" shadowing behavior used in the physical optics method is suggested as a source of larger errors observed as shadowing effects increase.

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Overview of the Conical Microwave Imager/Sounder development for the NPOESS program

Cited by 11 publications

References 1 publication

Theoretical study of the small slope approximation for ocean polarimetric thermal emission

Theoretical study of the small slope approximation for ocean polarimetric thermal emission

A rule-based method for scalable and traceable evaluation of system architectures

Higher ORDER Emission Model Study of Bi-sinusoidal Surface Brightness Temperatures

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