Detection of the bright band with a vertically pointing k-band radar

Abstract

Quantitative precipitation estimation based on weather radar data suffers from a variety of errors. During stratiform events, a region of enhanced reflectivity, called the bright band, leads to large positive biases in the precipitation estimates when compared with ground measurements. The identification of the bright band is an important step when trying to correct weather radar data for this effect. In this study we investigate three different methods to identify the bright band from profiles measured by a vertically pointing K-Band Micro Rain Radar (MRR). The first tries to fit a piecewise linear function to the profile. The bright band characteristics are then derived from the fitted function parameters. The second uses only reflectivity information, while the third makes additional use of the falling velocity, which is also measured by the MRR. This last method shows the greatest skill in identifying the bright band height, followed by the function fit and the pure reflectivity methods. A comparison with data from a scanning radar shows that the height estimated in this way corresponds well with the bright band features observed in the radar scan.

Keywords

• MRR
• Bright Band
• Vertical Profile of Reflectivity
• Falling Velocity
• Weather Radar