Meteorology

In the sky there is more than rain and snow. Other objects can be misinterpreted as rain by a weather radar. The main ones are[10]:


* Birds, especially in period of migration.
* Insects at low altitude.
* Thin metal strips (chaff) dropped by military aircraft to fool enemies.
* Solid obstacles such as mountains, buildings, and aircraft.
* Ground and sea clutter.
* Reflections from buildings if the radar is close enough to a city (called urban spikes).

Each of them has their own characteristics that make it possible to distinguish them to the trained eye but they may fool a layman. It is possible to eliminate some of them with post-treatment of data using reflectivity, Doppler, and polarization data.