Correlations between slant wet delays measured by microwave radiometry

We present an analysis of the correlation between the atmospheric slant wet delays in different directions using data from a microwave radiometer. The correlations between wet delays observed in different directions using different temporal constraints are compared to a model derived from theories of turbulence. The agreement between the model and the radiometer data was good, and the average squared difference between zenith mapped slant wet delays could be predicted with an accuracy of 0.01-0.04 cm². Our analysis shows a large short-term variability which variance has a seasonal dependence of about ±26%, largely depending on the refractivity structure constant C_n. We also demonstrate how the model can be used to characterize the stability of a microwave radiometer.