NOAA SkyWater radar deployed to northern California in support of HMT-West 2011 and CalWater

The ESRL Physical Sciences Division (PSD) recently deployed a C-band scanning Doppler radar to Lincoln, California in support of field activities associated with HMT-West 2011 and a collaborating project called CalWater. This radar, dubbed "SkyWater", was deployed in the area during the late 1970s and early 1980s as part of the Sierra Cooperative Pilot Project (SCPP). In SCPP, Skywater only produced reflectivity information. Over the past few years, PSD staff have upgraded the radar to provide Doppler capability.

A major thrust of HMT-West 2011 and CalWater is documenting atmospheric rivers (ARs). When they arrive in California, ARs contribute significantly to water supply and flood generation in the state. Although focused research during the last few years has shown linkages between ARs and both regional water supply and extreme precipitation events, there are still questions about how AR-generated precipitation is influenced by California's Sierra Nevada. The strong, concentrated winds blowing along this mountain range, called Sierra barrier jets (SBJs), are a dominant feature of Sierra Nevada storms and impact the way precipitation is distributed. Documentation of the structure of SBJs has provided important insights, but a lack of three-dimensional information hinders understanding of many critical details, such as how far SBJs extend horizontally, how they vary along the Sierra, and how they interact with ARs.

Data from SkyWater will be used in combination with data from NWS operational Doppler radars (KDAX and KBBX) to document the three-dimensional structure and evolution of SBJs. Field activities associated with HMT-West 2011 began on December 1st and will extend into mid-March 2011. Deployment of the Skywater radar at Lincoln is planned to continue into spring 2012.