Tropospheric absorption and dispersion of millimeter and submillimeter waves

Allen, Kenneth C.; Liebe, Hans J.

doi:10.1109/tap.1983.1143021

Cited by 9 publications

(2 citation statements)

References 6 publications

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“…This assumes that the effects of spatial water vapor variations are small compared with the attenuation due to the spatial cloud liquid water variations. This is consistent with earlier work [Allen and Liebe, 1983] which has shown that at 84 GHz the attenuation by a 20-km path of cloud liquid water 0.1 g m -3 is 3.3 times larger than the attenuation due to same path with 100% relative humidity. The surface emittance e• is estimated from the composite surface emittance values calculated in section 4, and the surface skin temperature, Ts, is assigned the value of the surface air temperature from the in situ sounding.…”

Section: Retrieval Of Cloud Liquid Water Is Attempted Only For 855-gmentioning

confidence: 99%

Passive microwave remote sensing of cloud liquid water over land regions

Jones¹,

Haar²

1990

J. Geophys. Res.

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Techniques for cloud liquid water retrieval over land are developed using data from the Special Sensor Microwave/Imager 85.5 GHz (3.5 mm) channels. To minimize the effect of surface emittance variability on the calculations, the surface emittance was estimated with the aid of surface skin temperature retrievals from the Visible Infrared Spin Scan Radiometer in geosynchronous orbit. The high sensitivity of the 85.5 GHz channels to cloud liquid water allows for the estimation of integrated cloud liquid water based on the microwave brightness temperature depression caused by attenuation and emission of microwave radiation at the colder ambient temperature of the cloud. The method assumes nonscattering radiative processes are dominant, therefore only nonprecipitating cloud liquid water is considered. Integrated cloud liquid water retrievals show good qualitative agreement with other available data sources. Numerical error sensitivity analysis show integrated cloud liquid water error estimates of 0.05-0.50 kg m -2 depending on the contrast of cloud over background. 1. 227-238, 1986. Wu, R., and J. A. Weinman, Microwave radiances from precipitating clouds containing aspherical ice, combined phase, and liquid hydrometeors, J. Geophys. Res., 89, 7170-7178, 1984. Yeh, H., and K. Liou, Remote sounding of cloud parameters from a combination of infrared and microwave channels, J. Clim. Appl. Meteorol., 22,201-213, 1983.

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Section: Retrieval Of Cloud Liquid Water Is Attempted Only For 855-gmentioning

confidence: 99%

Passive microwave remote sensing of cloud liquid water over land regions

Jones¹,

Haar²

1990

J. Geophys. Res.

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“…Perhaps the most useful calculations of atmospheric attenuation have been done by Liebe [1], who used a variant of the Van Vleck-Weisskopf (VVW) [2] equation for the line shapes of water vapor and other atmospheric constituents. It is a common practice in calculating atmospheric attenuation to add a frequency-dependent empirical correction factor to the calculation because none of the analytic line shapes developed thus far give accurate results in the atmospheric window regions.…”

Section: Atmospheric Limitationsmentioning

confidence: 99%

Terahertz Imaging, Millimeter-Wave Radar

McMillan

NATO Security Through Science Series

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The millimeter wave (MMW) band of frequencies extends from 30 GHz to 300 GHz, with some fuzziness on both ends of this spectrum. The terahertz (THz) band extends from about 200 GHz to about 30 THz, despite the fact that the lower frequencies in this range are not strictly 10 12 Hz or higher. These bands are also variously called submillimeter, far-infrared, and near-millimeter. In recent years, there has been some degree of hype associated with the capabilities of systems operating in these bands. Sometimes exorbitant claims have been made relative to the ability of these systems to see through walls, detect buried structures, and detect cancer cells, for example. In this chapter we shall examine some of these clams and assess their validity. We shall find that MMW and THz systems can do some amazing things, some of them not related to the above claims, and that there is substantial promise of even more interesting results. In this chapter we begin by discussing these atmospheric limitations, since they permeate the whole technology of MMW, sub-MMW, and THz technology. We then discuss MMW and THz sources, detectors, optics, and systems in separate sections. Finally, we present some results obtained using sensors operating in these bands. Perhaps the most interesting of these results demonstrate the capability to image objects at resolutions as good as λ/100, where λ is wavelength. These measurements show the connection between this sensor technology and applications to security.

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Atmospheric Remote Sensing in the Microwave Region

Elachi

Zyl

2006

Introduction to the Physics and Techniques of Remote Sensing

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Tropospheric absorption and dispersion of millimeter and submillimeter waves

Cited by 9 publications

References 6 publications

Passive microwave remote sensing of cloud liquid water over land regions

Passive microwave remote sensing of cloud liquid water over land regions

Terahertz Imaging, Millimeter-Wave Radar

Atmospheric Remote Sensing in the Microwave Region

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