Collaborative Research: Lidar and Modeling Applications from the Precision Atmospheric Marine Boundary Layer Experiment (PreAMBLE) Dataset

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The Precision Atmospheric Marine Boundary Layer Experiment (PreAMBLE) was a field study conducted from 17 May to 17 June 2012 based out of Point Mugu, CA. The central focus was to evaluate atmospheric dynamics associated with the atmospheric marine boundary layer near Point Conception and the California Bight. Airborne measurements were used to evaluate three major topics of research: the coastal jet near Point Conception, the Catalina eddy, and the initiation of coastally trapped wind reversals. PreAMBLE was highly successful and all major goals specified in the original proposal have been completed and published. Three unanticipated outcomes from PreAMBLE have prompted additional research. These include the sheer volume of unique and high quality data obtained, the unanticipated utility of the data collected by the cloud lidar, and the disappointing performance of operational and case-specific numerical simulations. Of the 15 research flights, only five have been required to address key issues from the original proposal. The current project for the remaining ten cases combined with the previous analyses will enable 1) a more comprehensive evaluation of the marine boundary layer characteristics within the Santa Barbara Channel such as height, temperature, and the horizontal pressure field, 2) examine the role of topography in forcing changes in marine boundary layer structure and cloud characteristics near Point Buchon, 3) analysis of marine layer structure, aerosol origin, and fine-scale structure based on the upward- and downward-pointing cloud lidars, and 4) critically evaluate the performance and capability of the Weather Research and Forecasting model in simulating the dynamics, thermodynamics, and cloud cover within the Santa Barbara Channel and near-coastal Pacific Ocean just west of Point Arguello.Intellectual Merit: Airborne measurements of the lower atmosphere offshore of southern California are rare since they are difficult to obtain, which makes the PreAMBLE dataset extremely valuable. Important characteristics of the complicated system near Point Conception and the Santa Barbara Channel have been revealed through case studies. Current conceptual models of the dynamics must make assumptions and neglect more complicated issues. These observations allow a critical examination of many of the assumptions. A synthesis of all of the flights during PreAMBLE will provide the community with information on the variability of the fine-scale features and quantify deviations between all cases. Contributions will be made in identifying the relative roles of forcing such as offshore flow and interaction with a complex boundary layer under different conditions. Not only will conceptual models of the dynamics be refined, but a critical examination of the numerical models will be conducted.Broader Impacts: The near-coastal environment near Point Conception and the Santa Barbara Channel continue to be of strategic importance. Meteorological phenomena in the marine boundary layer have prompted several major research efforts during the past two decades. Data collected as part of the PreAMBLE field study are among the few airborne measurements taken within this region and are essential for validation of previous conceptual models and provide a hard test for numerical simulations. This project will offer an opportunity for graduate student training in the observational aspects of atmospheric science, a focus that was identified as a key element for the June 2009 Advanced Study Program Colloquium. As with previous field experiments, graduate students from the University of Kansas and the University of Wyoming will become exposed to aircraft datasets and novel applications. The University of Wyoming King Air is a national facility that is available to the entire meteorological community. Advances in aircraft observation techniques including applications of lidar will promote further use by other scientists.