Vaisala IRIS, User Manual

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The MLHGT product produced by IRIS is a depiction of the melting level heights on a
Cartesian map. The melting level heights are determined on a user defined grid providing an
illustration how the melting level heights changes geographically.
Dual Polarization radar data is used as input along with a priori information. As with other
IRIS products, the
MLHGT product may be animated in time and overlayed with other data
to increase situational awareness of the precipitation structure in the atmosphere.
3.10.1 MLHGT Algorithm
IRIS dual polarization raw volume data is used as input for the MLHGT algorithm. This data
may come from either single PPI , volume, RHI , or sector scans. The algorithm also functions
independently from scan geometry matching data from the scan polar co-ordinate system
to an Earth relative co-ordinate system. However as with any radar observation, a higher
number of elevations in a volume scan provides the best results.
The following figure shows the
MLHGT algorithm flow diagram. The top level illustrates the
radar observation inputs, followed by prior information. The blocks represent consecutive
functional steps. A key qualifier for each step is expressed in parenthesis.
Chapter 3 – Configuring IRIS Products
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