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Observations of tropospheric phase scintillations at 5 GHz on vertical paths
Author(s) -
Armstrong J. W.,
Sramek R. A.
Publication year - 1982
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs017i006p01579
Subject(s) - troposphere , radiometry , environmental science , remote sensing , doppler effect , spacecraft , phase (matter) , interferometry , range (aeronautics) , microwave , very long baseline interferometry , noise (video) , geodesy , physics , geology , meteorology , optics , astronomy , materials science , quantum mechanics , composite material , image (mathematics) , artificial intelligence , computer science
We report here observations of tropospheric phase fluctuations at 5 GHz on the near‐vertical paths relevant to a number of astronomical and geophysical measurements. Using the Very Large Array near Socorro, New Mexico, the spatial structure function of phase was measured in the scale size range 1–35 km. The 23 data sets reported here were taken over a 2.5‐year interval. During 15 observing sessions there is a clear detection of tropospheric phase fluctuation, while only upper limits can be constructed on the remaining 8 days. The measured structure functions vary as (baseline) x , with the average value of x being 1.4. Where comparisons with other microwave observations (e.g., water vapor radiometry) are possible, there is reasonably good agreement in both the level and shape of the power spectrum of these tropospheric phase fluctuations. Some implications of these observations for precision Doppler tracking of spacecraft and geodesy/radio interferometry observations are discussed. Although the level of these tropospheric scintillations is highly time variable, very low frequency gavitational radiation searches using Doppler tracking of distant spacecraft will have, if uncalibrated, tropospheric propagation noise at a typical level Δƒ/ƒ∼ 5 × 10 −15 for 1000‐s integration times.