Geoscience Reference
In-Depth Information
precipitation amounts surrounding Aosta town indicate values between 16 and 25 mm in 24
hours (yellow patch). According to rain gauges, such amount still represent ~2 dB radar
underestimation: from 12 UTC of November 4 to 12 UTC of November 5, in fact, the gauges
“Aosta Piazza Plouves” (580 m MSL) and “Aosta St. Christophe” (550 m MSL) respectively
measured 44.2 mm and 40.2 mm.
Finally, it is worth noting that the very complex orography causes severe beam shielding:
the radar is practically blind at all ranges in the northern part of the circular surveillance
area while in the southern half-circle weather echoes are only detected in approximately
10% of the 30 km range.
Fig. 3b. 24-hour cumulative rainfall amounts in the north-western part of Italy as seen by the
low-cost X-band radar located near the town of Aosta (from 12 UTC of November 4 to 12
UTC of November 5, 2011). The circular range ring is at 30 km range from the site of the
mini-radar.
