Measurments of attenuation and refractive dispersion due to atmospheric water vapor at 80 and 240 GHz

Manabe, Tetsuya; Furuhama, Yoji; Ihara, T.; Saito, Shinji; Tanaka, Hiromochi; Ono, Akira

doi:10.1007/bf01041347

Cited by 13 publications

(13 citation statements)

References 7 publications

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“…Our measurement of 70 ± 10% x 10 −6 is consistent with 61 x 10 −6 for the early 9.2, 24 and 72 GHz measurements at 20 °C and 10 mm Hg (9.9 g/m 3 ) [1][2][3]. A field, line-of-sight measurement over an open 810 m outdoor path measured the refractivity difference between two sources of 80 GHz and 240 GHz, by measuring the differential phase delay [4]. Compared to the above frequency independent value of 61 x 10 −6 [1-3], the relatively small difference observed was between 1.15 x 10 −6 and 1.25 x 10 −6 for different daily temperatures with a water vapor density of 10 g/m 3 [4].…”

Section: Experimental Measurementssupporting

confidence: 81%

“…A field, line-of-sight measurement over an open 810 m outdoor path measured the refractivity difference between two sources of 80 GHz and 240 GHz, by measuring the differential phase delay [4]. Compared to the above frequency independent value of 61 x 10 −6 [1-3], the relatively small difference observed was between 1.15 x 10 −6 and 1.25 x 10 −6 for different daily temperatures with a water vapor density of 10 g/m 3 [4]. This measurement is consistent with a constant or slowing varying refractivity.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…The refractivity of water vapor is composed of two parts, a slowly-varying almost frequency-independent part, applicable from microwaves up to THz, into the infrared and the visible, and a strongly frequency-dependent part together with strong absorption in the water vapor rotational spectrum from 0.2 to 10 THz. Measurements of the refractivity of water vapor have been made at microwave [1,2], mmwave [3,4], far-infrared (THz) [5], infrared [6,7], and optical frequencies [8]. Previously, until the results described here, all measurements of the refractivity of water vapor, determined the sum of both parts.…”

Section: Introductionmentioning

confidence: 99%

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Time domain measurement of the THz refractivity of water vapor

Yang¹,

Mandehgar²,

Grischkowsky³

2012

Opt. Express

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Section: Experimental Measurementssupporting

confidence: 81%

Section: Experimental Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time domain measurement of the THz refractivity of water vapor

Yang¹,

Mandehgar²,

Grischkowsky³

2012

Opt. Express

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“…where L is the interval between the transmitter and the receiver. The phase difference ( ) between both radio waves, which is based on 245Ð52 GHz, is defined by the following equation (Manabe et al, 1985;Radio Wave Division, 1986):…”

mentioning

confidence: 99%

“…In Equations (3), (5) and (6), the interval (L) is 1Ð86 km, the following equation (Manabe et al, 1985;Radio Wave Division, 1986) is the lead:…”

mentioning

confidence: 99%

Measurement of atmospheric water vapour on the ground's surface by radio waves

Kishii

Kuzuha

Sugita

et al. 2001

Hydrological Processes

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Abstract:Water vapour in the atmosphere and various meteorological phenomena are essential to the understanding of the mechanism of the water cycle. However, it is very difficult to observe water vapour in the atmosphere because the quantities are usually observed at a single point not over long intervals or in a specific plane or volume. Accordingly, the use of radio waves is considered to be necessary to observe water vapour. Radio waves can be transmitted over long intervals and across large areas, and generally speaking, the characteristics of radio waves change due to material in the atmosphere, especially water vapour. Usually absorption is used to observe the quantity of water vapour. But the relationship between absorption and the quantity of water vapour is not linear, so we try to utilize the phase difference between two radio waves as an alternative method. First, the relationship between the phase delay and the water vapour was induced by a physical equation and the resulting phase delay was found to be proportional to the quantity of water vapour. Furthermore, the phase difference between two separate points was observed by use of two radio waves in the field, specifically 84 GHz and 245 GHz. For reference and comparison, water vapour density in the atmosphere was simultaneously observed by meteorological observation. As a result, the density of the water vapour was found to be proportional to the phase difference between the two radio waves. The result also shows that this method is able to measure the diurnal changes in water vapour density in each season.

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Refractive index of water vapor in infrared windows

Hill¹,

Lawrence

1986

Infrared Physics

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Measurments of attenuation and refractive dispersion due to atmospheric water vapor at 80 and 240 GHz

Cited by 13 publications

References 7 publications

Time domain measurement of the THz refractivity of water vapor

Time domain measurement of the THz refractivity of water vapor

Measurement of atmospheric water vapour on the ground's surface by radio waves

Refractive index of water vapor in infrared windows

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