Instrumental and spectral parameters: their effect on and measurement by microwave limb sounding of the atmosphere

Pumphrey, Hugh C.; Bühler, Stefan

doi:10.1016/s0022-4073(99)00106-5

Cited by 39 publications

(24 citation statements)

References 12 publications

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“…These results are presented in Fig. 3 together with the values obtained in [1]. It is well seen that the results of the previous measurements also show a large spread of data, and their diagreement is much greater than within the errors mentioned by the authors of [1].…”

supporting

confidence: 64%

“…This ensures high reliability of the obtained values of the molecule constants. Precision measurements of the line broadening of an oxy- Rusk [7], point 2, to Dryagin et al [8], point 3, to Frenkel and Woods [9], point 4, to Hemmi and Straiton [10], point 5, to Ryadov and Furashov [11], point 6, to Bauer et al [12], point 7, to Bauer et al [13], point 8, to Goyette and De Lucia [14], point 9, to Pumphrey and Buehler (MLS) [1], and point 10, to Pumphrey and Buehler (MAS) [1]. For obtaining points 11 and 12, we used the cavity spectrometer and the RAD spectrometer, respectively [15,16].…”

mentioning

confidence: 99%

“…Measurement results for the shift constant δ of the water molecule line near 183 GHz obtained by different research groups (presented in publication year order). Points 1 and 2 were obtained in [1] from measurements by the satelliteborne tools MLS and MAS, respectively, and point 3 obtained from the MAS data differs in the processing technique [1]. Points 1-3 are slightly separated on the horizontal axis for clarity.…”

mentioning

confidence: 99%

“…The shift measurement history of this line is much shorter. The air-pressure shift of this water line was discovered in 2000 during processing of the atmosphere limb sounding data by two tools, the MLS (Microwave Limb Sounder) mounted on the UARS (Upper Atmosphere Research Satellite) and the MAS (Millimeter-wave Atmospheric Sounder) mounted on the Space Shuttle [1]. Two values obtained by the authors of [1] differed twofold, but both indicated the existence of an effect coinciding in sign (and in order of magnitude).…”

mentioning

confidence: 99%

“…Allowance for the pressure shift of the water line significantly impaired the agreement of the calculated and experimental line profiles observed from the satellite. Estimating the case, the authors of [1] concluded that "Some parameters, including frequency shift by pressure, are difficult to measure in a laboratory. We think that the MLS tool can ensure a better measurement of the water-vapor line shift at a frequency of 183 GHz than any laboratory instruments known to us."…”

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confidence: 99%

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Obtaining precise constants of atmospheric lines in the millimeter and submillimeter wavelength ranges

Tretyakov

Golubiatnikov

Паршин

et al. 2008

Radiophys Quantum El

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An important physical problem of supplying the Earth's atmosphere satellite monitoring with precise laboratory measurements of the line constants of atmospheric gases has been resolved. We developed a complex of spectrometers and techniques which improves the accuracy of lineconstant measurements by about an order of magnitude. Systematic errors of measurements do not exceed the statistical ones. Agreement of the results obtained by two different spectrometers improves reliability of the measured constants. Examples of measurements of collisional constants (broadening, shift, and collisional coupling) for the most important diagnostic atmospheric lines of water and oxygen molecules are presented. A number of collisional constants of the molecules are obtained for the first time and some errors of the previous researchers are corrected. The measured parameters have been used for the international projects. Prospects for supplying planned satellite terahertz projects with precise laboratory data are pointed out.1. Global monitoring of the Earth's atmosphere, data acquisition for weather forecast, and prediction of climate variations are fulfilled, in the long run, by microwave radiometric measurements from satellites. Measurement of altitude distributions of the atmospheric temperature and humidity is based on observation of spectral lines of atmospheric gases, primarily water and oxygen molecules. The interpretation of complex profiles of atmospheric lines observed from a satellite requires laboratory measurements of collisional-interaction constants of the corresponding molecule transitions, including broadening, shift, and collisional coupling (interference) of spectral lines. The accuracy of knowledge of the mentioned constants determines the accuracy of retrieved information.Until very recent time, the required accuracy of laboratory measurements of these parameters has not been reached, especially in the millimeter and submillimeter wavelength ranges. For the most important diagnostic line of a water molecule at 183 GHz, the spread of values of the broadening constants measured in different laboratories reached 30%, and the shift constant was not measured in a laboratory at all [1]. The errors of determining the line broadening constants of an oxygen molecule reached up to 25% [2,3]. In this case, if the error of assigning the broadening constant exceeds 5%, it becomes the main in the total error of determining the atmospheric parameters [4]. Improvement of the accuracy of laboratory studies of the atmospheric-line constants is a topical problem in experimental physics, which is of great applied value.2. We developed a complex of spectrometers of the millimeter and submillimeter wavelength ranges with measurement and calibration techniques. As a result, the accuracy was increased by more than one order of magnitude amd the reliability of measurement of all mentioned molecule constants, such as broadening, shift, and collisional coupling of spectral lines, was improved.The complex comprises two types of spect...

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confidence: 64%