ASPECANDL

ARM Support for the Plains Elevated Convection at Night Experiment: Doppler Lidar Operations

1 June 2015 - 1 July 2015

Lead Scientist: David Turner

Observatory: SGP

The Plains Elevated Convection at Night (PECAN) experiment was a large field campaign that was supported by the NSF with contributions from NOAA, NASA, and DOE. The overarching goal of the PECAN experiment was to improve the understanding and simulation of the processes that initiate and maintain convection and convective precipitation at night over the central portion of the US Great Plains. These goals were important since: (a) a large fraction of the yearly precipitation in the Great Plains comes from nocturnal convection, (b) nocturnal convection in the Great Plains is most often decoupled from the ground and is thus forced by other phenomena aloft (e.g., propagating bores, frontal boundaries, low level jets), (c) there is a relative lack of understanding how these disturbances initiate and maintain nocturnal convection, and (d) this lack of understanding greatly hampers the ability of numerical weather and climate models to simulate nocturnal convection well which leads to significant uncertainties in predicting the onset, location, frequency, and intensity of convective cloud systems and associated weather hazards over the Great Plains. The ARM program provided a Doppler lidar that was deployed with one of the mobile PECAN Integrated Sounding Array (PISA) stations (M-PISA #3). Each PISA station had remote sensing instruments that were able to profile temperature, humidity, and winds throughout the boundary layer and lower troposphere at high time resolution (~5-min). The detailed characterization of the thermodynamic and kinematic evolution of the boundary layer across the experimental domain by the 6 fixed PISAs and the 4 mobile PISAs greatly enhanced the rest of the observational datasets, which included fixed and mobile 3-D scanning precipitation radars, mobile mesonet systems, clear air and storm penetrating aircraft, and mobile radiosonde launching systems. This experiment was tightly coupled with the ARM Support for PECAN experiment.