Geoscience Reference
In-Depth Information
brought in fully programmable signal processor and replaced the analogue receiver with the
digital receiver. In 2009 the NWS started the process of converting the radars to dual
polarization which should be accomplished by mid 2013.
The number of radars used continuously for operations is 159 and there are two additional
radars for other use. One is for supporting changes in the network brought by infusion of
new science or caused by deficiencies in existing components (designated KCRI in Norman,
OK). The evolution involves both hardware and software and the update in the former are
typically made annually. The other (designated KOUN in Norman, OK, USA) is for research
and development. Therefore its configuration is more flexible allowing experimental
changes in both hardware and software.
Conference articles and presentation about the WSR-88D and its data abound and there are
few descriptions of its basic hardware. Very recent improvements are summarized by
Saxion & Ice (2011) and a look into the future is presented in Ice & Saxion (2011). Yet only
few journal articles describing the system have been published. The one by Heiss et al.
(1990) presents hardware details from the manufacturer's point of view. The paper by Crum
et al. (1993) describes data and archiving and the one by Crum & Alberty (1993) contain
valuable information about algorithms. The whole No. 2 issue of Weather and Forecasting
(1998), Vol. 13 is devoted to applications of the WSR-88D with a good part discussing
products that use Doppler information. A look at the network with the view into the future
is summarized by Serafin & Wilson (2000).
As twenty years since deployment of the last WSR-88D is approaching there are concerns
about future upgrades and replacements. High on the list is the Multifunction Phased Array
Radar (MPAR). At its core is a phased array antenna wherein beam position and shape are
electronically controlled allowing rapid and adaptable scans. Thus, observations of weather
(Zrnic et al., 2007) and tracking/detecting aircraft for traffic management and security
purposes is proposed (Weber et al., 2007). Another futuristic concept is exemplified in
proposed networks for Cooperative Adaptive Sensing of the Atmosphere (CASA) consisting
of low power 3 cm wavelength phased array radars (McLaughlin et al., 2009).
Very few topics on weather radar have been written and most include Doppler
measurements. Here I list some published within the last 20 years. The one by Doviak &
Zrnic (2006) primarily concentrates on Doppler aspects and contains information about the
WSR-88D. The topic by Bringi & Chandrasekar (2001) emphasizes polarization diversity and
has sections relevant to Doppler. Role of Doppler radar in aviation weather surveillance is
emphasized in the topic by Mahapatra (1999). The compendium of chapters written by
specialists and edited by Meishner (2004) concentrates on precipitation measurements but
has chapters on Doppler principles as well as application to severe weather detection. Radar
for meteorologists (Rinehart, 2010) is equally suited for engineers, technicians, and students
who will enjoy its easy writing style and informative content.
2. Basic radar
The surveillance range, time, and volumetric coverage are routed in practical considerations
of basic radar capabilities and the size and lifetimes of meteorological phenomena the radar
is supposed to observe. This is considered next.
