[1] We investigate the potential of radio links such as employed by commercial cellular communication companies to monitor path-averaged rainfall. We present an analysis of data collected using two 38-GHz links during eight rainfall events over a 2-month period (October-November 2003) during mostly stratiform rainfall in the Netherlands. Comparisons between the time series of rainfall intensities estimated using the radio links and those measured by a nearby rain gauge and a composite of two C band weather radars show that the dynamics of the rain events is generally well captured by the radio links. This shows that such links are potentially a valuable addition to existing methods of rainfall estimation, provided the uncertainties related to the reference signal level, signal level resolution, wet antenna attenuation, and temporal sampling can be resolved.

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Outflow experiments, in combination with inverse modeling techniques, offer a time‐efficient way to simultaneously determine retention and hydraulic conductivity functions. Using outflow data only in the objective function, and applying the optimization algorithm of Marquardt's maximum neighborhood, the multistep outflow method results in unique estimates of the retention and hydraulic conductivity functions. For the same experimental conditions the one‐step outflow method often yields nonunique solutions. For the Mualem‐van Genuchten expression of the soil hydraulic functions, four parameters (α, n, Ks and λ) were estimated for a medium‐textured soil. Fixation of λ negatively affects the estimation of K(h). The reference curve as derived by similar media scaling corresponded with curves derived by the direct averaging of soil hydraulic functions, and with those obtained by optimization of the mean outflow for a set of 20 soil samples.

[1] The suitability of a 27-GHz microwave link for measuring path-averaged precipitation is investigated. Theoretical analyses show that the specific attenuation of an electromagnetic signal at this frequency varies nearly linearly with the rainfall intensity, which is ideal for line-integrating instruments. The dependence of this relation on the drop size distribution and on the temperature is small, so that uncertainties in these variables do not play large roles in the estimation of rainfall intensity. Data from an experiment with a 4.89-km microwave link and a line configuration of seven tipping bucket rain gauges are used to test whether this instrument is indeed suitable for the estimation of path-averaged rainfall. Results from this experiment show that the attenuation due to wet antennas can have a significant effect on the retrieved rainfall intensity. However, when a two-parameter wet antenna correction function is applied to the link data, comparisons with the rain gauge data show that the instrument is indeed well suited for the measurement of path-averaged rainfall.