Damaging Downburst Prediction and Detection Algorithm (DDPDA)
Algorithm Components
SCIT Algorithm
Parameters for each 2D cell component:
Azimuth/Range
Elevation Angle/Height AGL
Mass [bad]
Maximum Reflectivity
Area [bad]
SCIT Threshold
Parameters for each 3D cell:
Azimuth/Range
VIL
Mass [bad]
Height of Center of Mass
Volume [bad]
Core Aspect Ratio
DDPDA derived cell parameters:
Initial Core Height
Initial Max dBZ Height
Core Descent
Max dBZ Descent
Delta (Volume)
Delta (VIL)
Known problems:
Poor cell identification
Poor cell tracking
[Due to the poor quality of cell-based trends in
VCP 21, we need to emphasize the importance of using VCP 11 in highly convective
situations to our users]
[Look at the vertical reflectivity gradient to
find the base of the core]
Effects on DDPDA:
Can create false descending core signatures
Corrupt cell histories (unrealistic discontinuities and data holes)
Recent "fixes":
increased resolution for 2D component identification from 5 dBZ to 2 dBZ
reduced vertical continuity search step threshold to ensure the correct
components are linked in the vertical.
Possible future improvements:
Fill in remaining data holes in the reflectivity field [Lak
had some comments on this -- Lak, could you fill me in again on your proposed
solution? I didnt' quite grasp it the first time...]