In-situ observation of undisturbed surface layer scaler profiles for characterizing evaporative duct properties

Understanding the vertical variations of temperature and humidity in the marine atmospheric surface layer (MASL) is extremely important for naval and civilian applications. In particular, such variations affect the propagation of electromagnetic waves (EM) by forming an evaporation duct. However, direct measurements of these profiles have been difficult from a large ship because of the disturbance introduced by the platform. In this thesis, the design, deployment, and initial data analyses of a marine atmospheric profiling system (MAPS) is introduced. The MAPS is developed as part of the Coupled Air Sea Process and EM ducting Research (CASPER) project. It is capable of making repeated measurements of the lowest tens of meters of the MASL from a small Rigid Hull Inflatable Boat (RHIB), or a small work boat, equipped with a tethered profiling system and a small meteorological mast. For each profiling set at a given location, 10Ð15 profiles were made to allow sufficient samples to derive the mean profile. This thesis discusses the methods for controlling data quality and obtaining the mean profiles from the scattered profiling data. Evaporation duct height and strength are derived and compared to those generated from an evaporation duct model using various input from measurements.http://archive.org/details/insituobservatio1094549369Lieutenant, United States NavyApproved for public release; distribution is unlimited