2010-06-28 Matti Leskinen

Insect migrations towards NE

Time of the radar images is in UTC (EET-2, EEST-3). Radar elevation angle 0.5 degrees.

Plumes from Estonian islands and tips of the coastline, aphids maybe, smoke probably not. Similar plumes can be spotted starting from the islands near the Finnish coast.

Reflectivity 06:00

Reflectivity 06:15

Reflectivity 06:30

Reflectivity 06:45

Reflectivity 07:15

Reflectivity 07:45

Radial velocity 07:45

Unambiguous range (+/- 8 m/s) is a bit too small, but about 7 to 10 m/s flow from SW can be estimated.
Near Estonia the plumes orient more towards north, and radial velocity is smaller as well. This feature is probably caused by the fact that in the beginning insects fly lower, but the radar has no problems in detecting them.

Differential reflectivity 07:45

In practice the main cloud of insects at the Finnish coastline has collective orientation along SE-NW axis. The plumes over the sea can not be said to be anything different, the scatterers look much flattened (horizontally elongated).

Matti.Leskinen@helsinki.fi