Comparison between cross-track and conical scanning microwave window channels near 90 GHz

Wessel, John E.; Boucher, D. J.

doi:10.1109/36.655314

Cited by 9 publications

(2 citation statements)

References 15 publications

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“…These results are not consistent with the suggestion from Wessel and Boucher [1998] that the strength of the water vapor continuum needs to be increased by 9% in MPM89, on the basis of comparison of SSM/I and SSM/T‐2 data over the tropical south Pacific, as I found this model to be unbiased in these conditions. However, Rosenkranz and Barnet [2006] found no significant bias in the Ros03 model when comparing accurate, collocated radiosondes with 150 GHz and 183 GHz observations from the Humidity Sounder for Brazil (HSB) in tropical and midlatitude sites.…”

Section: Discussioncontrasting

confidence: 75%

Aircraft validation of clear air absorption models at millimeter wavelengths (89–183 GHz)

Hewison¹

2006

J. Geophys. Res.

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[1] Measurements with an airborne microwave radiometer are used to validate absorption models in clear air at frequencies used in satellite microwave humidity sounders, such as AMSU-B and MHS. The data set includes 33 profiles of radiometric and in situ observations ranging from the tropics to the high arctic. In cold, dry conditions the MPM and Rosenkranz models were found to underestimate the observed downwelling radiances near the surface in window channels dominated by the water vapor continuum. The models' absorption coefficient is calculated and found to be strongly deficient compared to observations in layers of low specific humidity. For medium humidity, the models' negative bias persists at 89 GHz and becomes statistically significant, but reduces at higher frequencies. Previously, the radiometer calibration had been adjusted to fit modeled radiances during high-level flight; this approach has been revised in the light of these findings and a tip curve method applied. Possible spectroscopic reasons for the models' deficits are suggested, including the underestimation of continuum terms or the extrapolation of oxygen line coupling coefficients to low temperatures. The impacts for operational use of radiative transfer models are discussed.

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Section: Discussioncontrasting

confidence: 75%

Aircraft validation of clear air absorption models at millimeter wavelengths (89–183 GHz)

Hewison¹

2006

J. Geophys. Res.

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“…The polarization state for SSM/T-2 is sometimes given as "unspecified." In some studies ( [29] for instance), SSM/T-2 has been assumed to observe vertical polarization at nadir, whereas horizontal polarization at nadir has been assumed by Wessel and Boucher [30] in their comparison of the SSM/I and SSM/T-2 window channels near 90 GHz. From comparisons between observations and simulations, Burns et al [31] concluded that the instrument is observing the horizontal polarization at nadir and this has been confirmed to them by information from the Aerojet system engineers for the SSM/T-2 project.…”

Section: The Angular Dependence Of the Microwave Land Surface Emimentioning

confidence: 99%

Frequency and angular variations of land surface microwave emissivities: can we estimate SSM/T and AMSU emissivities from SSM/I emissivities?

Prigent

Wigneron²,

Rossow

et al. 2000

IEEE Trans. Geosci. Remote Sensing

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To retrieve temperature and humidity profiles from special sensor microwave/temperature (SSM/T) and advanced microwave sounding units (AMSU), it is important to quantify the contribution of the Earth surface emission. So far, no global estimates of the land surface emissivities are available at SSM/T and AMSU frequencies and scanning conditions. The land surface emissivities have been previously calculated for the globe from the SSM/I conical scanner between 19 and 85 GHz. To analyze the feasibility of deriving SSM/T and AMSU land surface emissivities from SSM/I emissivities, the spectral and angular variations of the emissivities are studied, with the help of ground-based measurements, models, and satellite estimates. Up to 100 GHz, for snow and ice free areas, the SSM/T and AMSU emissivities can be derived with useful accuracy from the SSM/I emissivities. The emissivities can be linearly interpolated in frequency. Based on ground-based emissivity measurements of various surface types, a simple model is proposed to estimate SSM/T and AMSU emissivities for all zenith angles knowing only the emissivities for the vertical and horizontal polarizations at 53 zenith angle. The method is tested on the SSM/T-2 91.655 GHz channels. The mean difference between the SSM/T-2 and SSM/I-derived emissivities is 0.01 for all zenith angles with a root mean squared (RMS) difference of 0.02. Above 100 GHz, preliminary results are presented at 150 GHz based on SSM/T-2 observations and are compared with the very few estimations available in the literature.

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Characterisation of Special Sensor Microwave Water Vapor Profiler (SSM/T-2) radiances using radiative transfer simulations from global atmospheric reanalyses

Kobayashi

Poli

John

2017

Advances in Space Research

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Comparison between cross-track and conical scanning microwave window channels near 90 GHz

Cited by 9 publications

References 15 publications

Aircraft validation of clear air absorption models at millimeter wavelengths (89–183 GHz)

Aircraft validation of clear air absorption models at millimeter wavelengths (89–183 GHz)

Frequency and angular variations of land surface microwave emissivities: can we estimate SSM/T and AMSU emissivities from SSM/I emissivities?

Characterisation of Special Sensor Microwave Water Vapor Profiler (SSM/T-2) radiances using radiative transfer simulations from global atmospheric reanalyses

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