Research Summaries

Back Coupled Air Sea Processes and EM Ducting Research (CASPER)

Fiscal Year 2015
Division Graduate School of Engineering & Applied Science
Department Meteorology
Investigator(s) Wang, Qing
Sponsor Office of Naval Research (Navy)
Summary We propose a collaborative research effort, dubbed Coupled Air-Sea Processes and EM Ducting Research (CASPER), to address overarching knowledge gaps related to electromagnetic (EM) wave propagation in coastal Marine Atmospheric Boundary Layers (MABL). The objective is to fully characterize the MABL as an EM propagation environment. The emphases will be on spatial heterogeneities and surface wave/swell effects, both of which contravene underlying assumptions of Monin-Obukhov Similarity Theory (MOST) used in coupled environmental forecast models and evaporative duct models. Furthermore, coastal variability in the elevated trapping layer atop the MABL presents a challenge to forecast models and also causes practical issues in trapping layer interpolation in EM prediction models. These issues are the target of investigation in this project.
Our approach includes theoretical analyses, field measurements, and numerical modeling. Theoretical analyses will guide our field experimental design and data analyses. The field components have two main campaigns: CASPER-East (Duck, NC) and CASPER-West (Southern California). These two campaigns will capture ducting along developing internal boundary layers over inhomogeneous regions near the Gulf Stream, evaporative ducts over warm water and affected by wave/swell, and surface-based and elevated ducts near the MABL top under coastal influence. Each campaign is preceded by a yearlong monitoring effort at respective sites to capture broader range of MABL conditions and associated EM propagation variations. Unique to this project is an optimal combination of platforms and sensors for high-resolution measurements on either side of the air-sea interface away from regions of ship influence, as well as in the higher atmosphere. Also unique to CASPER is the concurrent measurements of MABL turbulence, scalar mixing and detailed range-dependent propagation measurements. The data analyses will address scientific questions related to the three hypotheses relevant to spatial heterogeneity, waves and swell, and novel approaches to EM propagation modeling and signal characterization. We will also analyze data from previous field projects and laboratory experiments to be conducted by our partners to address the above hypotheses. CASPER modeling efforts utilize high-resolution models such as large-eddy-simulations of dynamically coupled air, surface waves and upper ocean, single column and mesoscale models and various propagation modeling approaches. Also explored will be an ensemble approach to EM propagation forecast by introducing variability of the environmental field in propagation models.
Our management approach includes the oversight of an advisory committee with experts in multidisciplinary fields to evaluate project progress and provide constructive advice for future directions. The involvement of scientists from various Navy labs as unfunded collaborators will help establish an efficient transition path of our results to the Navy's operational environmental forecasting models and EM propagation predictions for tactical applications.
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal