Rainfall Over Land (con’t)
Rainfall detection via scattering 85/89 GHz:
- TB depressions indicate possible rain
- Larger the depression, heavier rain
- Proper rain/no-rain threshold to minimize noise
- Scattering Index=f(TB19,TB22)-TB85
Rain Rate - radar tuned; RR = a SI b
Accuracy and limitations:
- Instantaneous rate +/- 50%
- Summer season rain/no-rain most reliable
- “W. Coast” land systems problematic:
- maritime air mass/less ice/smaller precipitation particles?
- Single SI-RR used (ie, global “Z-R” relationship)
- Melting snow in winter and spring seasons
- False moderate rain rates
- “Stationary”