2.1            SWI – Severe Weather Indicator

Concept

The Severe Weather Indicator product (SWI) analyses the radar volume data to detect the following severe weather phenomena:

·      Storm areas and reflectivity cores

·      Mesocyclones and Meso-Anticyclones

·      Regions of divergence and convergence

·      Microbursts

The benefit is that SWI provides the user with an overview of hazardous weather phenomena within one image display. The SWI product needs radar data from a volume scan with Z, V, and W data scanned simultaneously.

For each type of weather phenomena a different kind of symbol is used. The visualization is done using a dynamic overlay onto every top projection product.

Product Definition

The SWI product worksheet consists of four tabs, one for each weather phenomena:

·      Microburst              Þ explained here

·      Storm                     Þ explained in chapter 6.1

·      Mesocyclone         Þ explained in chapter 6.2

·      Con-Divergence    Þ explained in chapter 6.4

The different weather phenomena are derived in different algorithm steps of the SWI product. Storm, Mesocyclone, and Con-Divergence algorithms are independent of each other, which is why they are available as stand-alone products (see corresponding chapters). The Microburst algorithm however is based on the output of the other three algorithms. Therefore, in the following only the Microburst algorithm is explained in detail. For the definition of the other algorithms, please refer to the before-mentioned chapters.