May 21 - July 30
Examining Polarimetric Characteristics of Electronic Interference in Weather Radar Data
Thong Phan, Valiappa Lakshmanan, and John Krause
What is already known:
- The National Weather Service network of radars has been recently upgraded to dual-polarization radars, allowing quality control algorithms to be implemented.
- Quality Control algorithms can aid in the removal of non-meteorological echoes.
- Automated systems mistakenly forecast electronic interference as precipitation due to its high reflectivity values.
What this study adds:
- Reflectivity values at or greater than 20 dBZ along with RhoHV values greater than 1 could indicate the radar is forecasting a false echo.
- Zdr values of electronic interference occur well below -2dB and above 6 dB.
- Dual-polarization product comparisons other than Z, Zdr ,and RhoHV values of electronic interference must be assessed to find more objective criteria for aiding in the quality control algorithms.
Abstract:
Meteorologists have been able to examine the atmosphere using weather radars to look at what kinds of precipitation have been occurring for many decades. With the recent upgrade to dual-polarization radars (dual-pol) for the WSR-88D (Weather Surveillance Radar 1998 Doppler), meteorologists can now examine the atmosphere with dual-polarization products. These products are: Velocity (V), Reflectivity (Z), Differential Phase on Propagation (PhiDP), Correlation Coefficient (RhoHV), Differential Reflectivity (Zdr), and Spectrum Width (SPW). Though the products are very useful in determining what type of precipitation are in the atmosphere, how large the precipitation event is, and how severe it can be, it picks up many non- meteorological echoes. Electronic interference is a type of non-meteorological echo that has high reflectivity values and is mistakenly forecasted as precipitation by automated systems. This study looks at the reflectivity, differential reflectivity, and correlation coefficient of electronic interference and precipitation to find objective criteria to distinguish a difference between them. The findings are meant to aid in the current quality control algorithm to be more efficient for operational use.