Vertical structure of boundary layer convection during cold‐air outbreaks at Barrow, Alaska Journal Article uri icon



  • AbstractBoundary layer convection (BLC) is common over high‐latitude oceans and adjacent coastal regions when a cold airmass becomes exposed to a sufficient fetch of open water. The vertical structure of mixed‐phase BLC clouds and precipitation is examined using the Atmospheric Radiation Measurement Program data set collected at the North Slope of Alaska (NSA) site at Barrow, Alaska. BLC may occur at this location in autumn, when cold air masses originating at higher latitudes advect southward over the still ice‐free coastal waters north of Alaska. This study identifies such BLC and documents its occurrence and characteristics. Instruments used for this study include profiling Ka band radars, a depolarization backscatter profiling lidar, a scanning X band radar, a microwave radiometer, a ceilometer, surface meteorological probes, and radiosondes. Six criteria are applied to objectively identify the BLC events, using data collected between 2004 and 2013. BLC episodes are relatively common at the NSA site, but almost exclusively in the month of October, and most episodes are relatively short, less than 10 h in duration. Liquid water is commonly found in these mixed‐phase BLC clouds, with a typical liquid water path of 150 g/m2, and snowfall rates average ~3 mm h−1 (water equivalent), in some cases over 10 mm h−1, notwithstanding the low cloud echo tops (~1.0–1.5 km). In one rather weak but persistent episode fall speed estimates derived from the profiling Ka band radar indicates the presence of rimed particles, confirming the convective nature of this precipitation.

publication date

  • January 16, 2016

has restriction

  • bronze

Date in CU Experts

  • December 25, 2021 12:22 PM

Full Author List

  • Wang Y; Geerts B; Chen Y

author count

  • 3

Other Profiles

International Standard Serial Number (ISSN)

  • 2169-897X

Electronic International Standard Serial Number (EISSN)

  • 2169-8996

Additional Document Info

start page

  • 399

end page

  • 412


  • 121


  • 1