Sensing the earth's atmosphere with occultation satellites

Lusignan, B. B.; Modrell, G.; Morrison, Alastair; Pomalaza, J.; Ungar, Steven G.

doi:10.1109/proc.1969.7000

Cited by 40 publications

(21 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Approximately at the same time Fischbach (1965) and Lusignan et al (1969) proposed the use of the same technique for the sounding of the Earth's atmosphere. Later the concept of the RO sounding was analyzed in many publications (e.g., Murray and Rangaswamy 1975;Murray 1977;Rangaswamy 1976;Gurvich et al 1982;Gurvich and Sokolovskiy 1985;Gorbunov 1988), and tested experimentally from the Salyut-7 space station (Volkov et al 1987;Grechko et al 1987).…”

Section: Radio Occultation Measurementmentioning

confidence: 99%

Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Luntama¹,

Kirchengast²,

Borsche³

et al. 2008

Bulletin of the American Meteorological Society

105

View full text Add to dashboard Cite

show abstract

Section: Radio Occultation Measurementmentioning

confidence: 99%

Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Luntama¹,

Kirchengast²,

Borsche³

et al. 2008

Bulletin of the American Meteorological Society

105

View full text Add to dashboard Cite

show abstract

“…The excess Doppler shift can also be expressed in terms of the angle of _._ refraction of the ray from its direction in the vacuum. According to Lusignan et al [1969], the horizontal component of the gradient of reft'activity normal to the occultation plane defined by the source, the receiver, and the Earth center (Figure 1) has very little effect on the rays, so that the bending remains principally dominated by the gradients in the plane of occultafion. Although sounding generally integrates information in two directions, along the limb and across it as a result of the receiver's motion around its orbit, the resulting atmospheric profiles are generally credited to a singl• direction, i.e., at the vertical of the ray perigee.…”

Section: Paper Number 96rs03599mentioning

confidence: 99%

Effect of periodic horizontal gradients on the retrieval of atmospheric profiles from occultation measurements

Belloul¹,

Hauchecorne²

1997

Radio Science

View full text Add to dashboard Cite

Abstract. Spherical symmetry is generally assumed during the retrieval process of atmospheric prof'des from occultation measurements. The existence of periodic horizontal gradients, occurring on scales comparable to the distances traveled by the rays around their tangent point, is produced by gravity waves. These waves can introduce density perturbations of up to 1 or 2 % in amplitude and affect the retrieved parameters accordingly. We show the consequences of ignoring these gradients in the retrieved refractivity profiles when spherical symmetry is assumed. We f'md that only the waves, with horizontal wavelengths close to the horizontal distance that rays travel in their f'mal 6 or 8 km in the vertical before they are tangent in the atmosphere, will have an influence on the retrieved profiles by introducing a phase delay in the local prof'de of the retrieved refractivity. The horizontal wavelength of these waves corresponds to the minimum horizontal resolution associated with the retrieved profiles. We also find that smaller scale waves do not have any significant impact on the retrieved prof'des, as their contribution cancels out by averaging through the periodic perturbation, while waves with very long horizontal wavelengths are in good agreement with a local spherical symmetry assumption.

show abstract

“…The planetary explorations have stimulated the theoretical study of its potential application to the Earth's atmosphere (Phinney and Anderson 1968;Lusignan et al 1969). However, until recently RO studies of Earth's atmosphere did not receive serious consideration, primarily because of the prohibitive cost of space-borne transmitters with stable clocks and the insufficient accuracy of satellite positioning.…”

Section: Introductionmentioning

confidence: 99%

Inversion and Error Estimation of GPS Radio Occultation Data

Kuo

Wee

Sokolovskiy

et al. 2004

Journal of the Meteorological Society of Japan

389

353

View full text Add to dashboard Cite

In this paper, we describe the GPS radio occultation (RO) inversion process currently used at the University Corporation for Atmospheric Research (UCAR) COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) Data Analysis and Archive Center (CDAAC). We then evaluate the accuracy of RO refractivity soundings of the CHAMP (CHAllenging Minisatellite Payload) and SAC-C (Satellite de Aplicaciones Cientificas-C) missions processed by CDAAC software, using data primarily from the month of December 2001. Our results show that RO soundings have the highest accuracy from about 5 km to 25 km. In this region of the atmosphere, the observational errors (which include both measurement and representativeness errors) are generally in the range of 0.3% to 0.5% in refractivity. The observational errors in the tropical lower troposphere increase toward the surface, and reach @3% in the bottom few kilometers of the atmosphere. The RO observational errors also increase above 25 km, particularly over the higher latitudes of the winter hemisphere. These error estimates are, in general, larger than earlier theoretical predictions. The larger observational errors in the lower tropical troposphere are attributed to the complicated structure of humidity, superrefraction and receiver tracking errors. The larger errors above 25 km are related to observational noise (mainly, uncalibrated ionospheric effects) and the use of ancillary data for noise reduction through an optimization procedure. We demonstrate that RO errors above 25 km can be substantially reduced by selecting only low-noise occultations.Our results show that RO soundings have smaller observational errors of refractivity than radiosondes when compared to analyses and short-term forecasts, even in the tropical lower troposphere. This difference is most likely related to the larger representativeness errors associated with the radiosonde, which provides in situ (point) measurements. The RO observational errors are found to be comparable with or smaller than 12-hour forecast errors of the NCEP (National Centers for Environmental Prediction) Aviation (AVN) model, except in the tropical lower troposphere below 3 km. This suggests that RO observations will improve global weather analysis and prediction. It is anticipated that with the use of an advanced signal tracking technique (open-loop tracking) in future missions, such as COSMIC, the accuracy of RO soundings can be further improved.

show abstract

Sensing the earth's atmosphere with occultation satellites

Cited by 40 publications

References 9 publications

Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Effect of periodic horizontal gradients on the retrieval of atmospheric profiles from occultation measurements

Inversion and Error Estimation of GPS Radio Occultation Data

Contact Info

Product

Resources

About