Radar in Precipitation Measurements: Where do we Stand

The sources of error in radar estimates of precipitation have been identified and described in the past. Some progress has been made in quantifying the errors. But in order to use radar as a hydrological tool as well as a ground truth for model validation, the structure of these errors must be determined. This question precedes the combination of radar and gages.

The problem is even more critical if we want to incorporate radar reflectivity information in data assimilation. This is a non-trivial task. The importance of the various sources of error is range dependent and it changes with the type of weather. It is also dependent on the characteristics of the radar and the particular orography in which the radar is set up.

Radar composites from continental scale networks, while opening new and exciting possibilities, present new difficulties as well when we are confronted with the need of producing a consistent precipitation map of the entire network.

The discussion will summarize the progress of the last fifteen years. It will emphasize the unresolved old questions as well as the new problems, and the role of the technological advances in solving some of these problems.