AP Filtering
AP
is perplexing for radar analysis. The beam can super-refract (over-arc
towards the ground) in inversion situations or sub-refract (under-arc
towards the key) in super-adiabatic conditions, giving:
Basic URP reflectivity products have no AP suppression. Doppler
reflectivities do; echoes with zero radial velocity are filtered out.
This remains an imperfect solution.
- fictitious echoes
- fictitious cells
- incorrect values for features like hail or echo tops
Attempts are being made to
nowcast the beam height and identify AP in real time, but the results
have been mixed. How this is being done is beyond the scope of this
course.