Fig. 2

Time series of tropospheric opacities from the MWR and radiosonde data. Black and red open circles indicate the tropospheric opacities calculated from the radiosonde data and those measured with the MWR within ±30 min of the radiosonde observation, respectively. Gray open circles are the differences between the measured and calculated tropospheric opacities, and blue closed circles and error bars denote the monthly mean differences and their standard deviations (±1σ), respectively. Green dash lines indicate the times of the change in the instrumentation described in Table 1