Radar Images
IMAGes from METEOROLOGICal radar of teolo and Concordia Sagittaria (ARPAV), and FOSSALON (OSMER)
|
RADAR SITE
|
BASE Section Corrected Intensity (dBZ)
|
PPI 1.5° Corrected Intensity (dBZ)
|
 |
 |
|
| CONCORDIA SAGITTARIA |  |
 |
Vertical Maximum Intensity (dBZ) |
Surface Rainfall Total (mm) |
|
FOSSALON |
 |
 |
The images of Radar in Teolo and Concordia Sagittaria represent with different colors, the extimation of intensity of precipitation phenomena. The measure represented in the maps is the reflectivity, that is the fraction of energy reflected by hydrometeora and returning to the Radar Antenna. The unity used for the reflectivity is the Decibel, also called dBz. To give an idea we can consider that 23 dBz are equivalent to 1 millimeter/hour for precipitation intensity; the intensity will double every 5 dBz. In case of thunderstorms the reflectivity increases to values like 50 dBz, but can exceed 60 dBz in presence of hail. Two kind of images are available, with range (radius) of 125 and 250 km respectively.
The Radar map from the site of Fossalon di Grado (VMI, acronym of Vertical Maximum Intensity) represents the maximum reflectivity value present on the vertical of every point. The VMI can be used for a general monitoring, because it allows to distinguish very well the areas in which occour important phenomena and to classify them basing on their typology (fronts, convective systems, etc). The riflectivity Z is directly correlated to the density, and therefore to the content of water, of the cloud. Values of Z over 10-15 dBZ usually (but not necessarily) mean a precipitation at the ground. The precipitation becames intense in the areas where the reflectivity is over 40 dBZ and very intense when the values reach and come through the 50 dBZ (typically in correspondence to storms).
