Non-Precipitation also Known
as Clear-air Echoes
Sunrise/sunset
spikes
Ground
clutter
Anomalous propagation
Radar Calibration and Testing
Wildlife
Chaff
Range
folding
Sea
Breeze Fronts
Wind
Power
Turbines
and "Wind Farms"
How many clear-air echoes can you identify in this animation?
(Note that there is a gap in the time continuity due to KMLB
going down for maintenance). In the 12Z sounding for Cape
Canaveral on November 20 multiple inversions can be seen:
Anomalous Propagation (AP)
Anomalous propagation of radar echoes refers to
meteorological situations where a signal comes back to the
radar antenna even in the absence of
precipitation. In many cases it occurs when atmospheric
conditions are favorable for superrefraction.
The following loop
shows
a
region of AP; note the blue-gray region of echoes that
forms then disappears southeast of Billings, MT. No
precipitation was noted at KBIL, nor were showers or virga
reported to the southeast
KBIL 162056Z 22014KT 10SM
BKN070 04/M08 A3013 RMK AO2 SLP230 ACSL DSNT N-E T00441078 56023
KBIL 161956Z 22015KT 10SM BKN065 04/M07 A3015 RMK AO2 SLP236 ACSL
NE-E T00391072
KBIL 161856Z 22015KT 10SM BKN070 03/M08 A3017 RMK AO2 SLP246 ACSL
W-E T00281083
KBIL 161756Z 22014KT 10SM BKN070 BKN095 01/M09 A3021 RMK AO2
SLP261 T00061089 10006 21039 58003
KBIL 161656Z 21013KT 10SM BKN060 BKN090 M01/M10 A3022 RMK AO2
SLP266 T10061100
KBIL 161556Z 20012KT 10SM BKN095 M02/M09 A3022 RMK AO2 SLP268
T10171094
Visible
satellite images indicated mountain waves, but not
widespread precipitation-producing clouds.
Nearby soundings from North Platte, Nebraska and Rapid City,
South Dakota showed pronounced inversions which could contribute
to supperrefraction.
Another example
of
AP.