www.radartutorial.eu Radar Basics

The Bright Band

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Figure 1: A typical RHI scan for a stratiform event with “Bright Band”

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Figure 1: A typical RHI scan for a stratiform event with “Bright Band”

The Bright Band

The Bright Band can be seen as the very dark region in RHI (Range-Height-Indication) scans (as seen in Figure 1). The power reflected back to the radar is related to the rainfall intensity and therefore radar beams striking this melting layer of snow causes overestimation of precipitation.

Bright Band

Bright Band problems relate to the comparative reflectivity of particular object types (in this case, precipitation). The supporting graphic shows the different stages of precipitation, leading to the bright band effect.

It is normal for precipitation to first form at high levels in the atmosphere. In this region, the temperature is normally below the freezing point of water. The precipitation forms initially as a succession of very small ice crystals which begin to fall towards the earth's surface.

The Bright Band needs to be detected and corrected for. In addition to this, when estimating precipitation intensity, determining which hydrometeors (i.e. Rain and Snow) the beam intersects is crucial to the calculation.

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