December 09, 2002: Light Stratiform Precipitation with embedded Non-meteorological Scatterers Author: Pam Heinselman, CIMMS/OU Last Updated: 9 April 2003

Forecast/Weather:

On 9 December 2002, light stratiform precipitation develops ahead of an approaching shortwave trough in the westerlies. Non-meteorological scatterers are embedded within this precipitation, mostly in areas southwest and southeast of KOUN. Characteristics of ZDR (high) and RhoHV (moderate) associated with these non-meteorological scatterers suggest that they *may be* chaff.

Radar Operations:

Start time: 15:24 12/09/02 UTC (09:24 12/09/02 local time)
Stop time: 23:53 12/09/02 UTC (17:53 12/09/02 local time)

Radar/Operational Status:

Hydrometeor Classification Algorithm: Cold season

Operational Delivery:

Not applicable.

Snapshots:Two examples of non-meteorological scatterers embedded in stratiform echo (Figs. 1-4, 5-8)

Figure 1: The radar reflectivity image at 18:50 UTC 9 December 2002 indicates light stratiform precipitation over central Oklahoma, but no non-meteorological scatterers.	Figure 2: Areas of high differential reflectivity are embedded in precipitation signal southwest and southeast of KOUN at 18:50 UTC 9 December 2002.
Figure 3: Correlation coefficients colocated with areas of high differential reflectivity range from 0.7 - 0.93, values which *may* indicate with chaff.	Figure 4: The hydrometeor classification algorithm identifies non-meteorological scatterers as snow at 18:50 UTC 9 December 2002.

Figure 5: The radar reflectivity image at 22:59 UTC 9 December 2002 indicates light stratiform precipitation over central Oklahoma, but no non-meteorological scatterers.	Figure 6: An area of high differential reflectivity 75-100 km south-southeast of KOUN indicates non-meteorological scatterers at 22:59 UTC 9 December 2002.
Figure 7: Correlation coefficients colocated with the area of high differential reflectivity south-southeast of KOUN range from 0.7 - 0.93, values which may indicate chaff.	Figure 8: The hydrometeor classification algorithm identifies non-meteorological scatterers as a mix of stratiform precipitaiton and biological scatterers at 22:59 UTC 9 December 2002.