Interferometric measurement of tropospheric phase fluctuations at 22 GHz on antenna spacings of 27 to 540 m

Phase fluctuations at 22 GHz introduced by tropospheric events were measured by observing cosmic compact radio sources with the Nobeyama millimeter-wave array on antenna spacings of 27 to 540 m. The observed interferometer phases were used to derive Allan standard deviations of phase fluctuations. The standard deviations had good relations to antenna spacing as a function, . The exponent derived from the observations in February distributed around 5/6 as expected from the Kolmogorov turbulence model, but was smaller than 5/6 from the observations in May. Time domain spectra of also imply that atmospheric structures (such as moist air, clouds, precipitation, etc.) have seasonal variations. Meteorological parameters monitored at the height of 20 m did not show good correlations to .