Nearly all aspects of marine atmospheric boundary layer (MABL) structure variability are strongly influenced by vertical and horizontal gradients in water vapor, temperature and turbulent mixing magnitude and structure that are controlled in part by atmospheric inversions. Practically, inversions create trapping or sharp discontinuities in atmospheric refractive index, influence aerosol hygroscopic growth and scintillation, and determine many of the properties of marine boundary layer clouds. To date, the fundamental physics and dynamics of clouds and its relationship to inversion lifecycle have not been fully connected to the regulation of energy exchange between the 1) ocean mixed layer, 2) atmospheric mixed layer, and 3) free troposphere. Such an understanding is required to understand where and when air-sea interaction assumptions and numerical parameterizations break down, leading towards work to improve prediction of maritime boundary layer structure and clouds.
This DRI will focus on the linchpin problem of how cloud related atmospheric exchange and radiation processes regulate the inversion lifecycle and affect coupled marine boundary layer and ocean processes. Two international field campaign components in different inversion environments are planned (with alternative domestic environments identified as fallbacks). Research ship and aircraft time leveraging ONR’s Code 321 UNOLS Research Facilities support will be used and refined with the MAGPIE PI team.
Objective
The objective of this proposal is to understand the physical mechanisms that control the evolution of the marine atmospheric boundary layer inversion top and, in turn, provide a conceptual theory of how inversions, aerosol/cloud particulates, and moisture fluxes interact as a holistic system to modulate the atmospheric and ocean surface/boundary layers. This topic seeks to produce new understanding of how small-scale and rapidly evolving boundary layer variability produce larger scale structures (e.g., cloud patterns) that can foster predictability in physics parameterizations and numerical modeling. Specific science questions include:
- How well does a static “one dimensional” profile of atmospheric properties (e.g., via a radiosonde vertical profile) represent the dynamic volumetric structure of the MABL’s water vapor and aerosol fields? Can that dynamic structure be accurately represented in large eddy simulations and parameterized in mesoscale modeling?
- How do warm, moist, and aerosol laden air parcels originating near the surface travel through the boundary layer, clouds and exchange with the free troposphere? How do cloud processes (condensation, entrainment/detrainment, radiation) influence MABL motions down to the ocean’s surface and feed back into air/sea interaction?
- How do the MABL clouds self-organize (e.g., cloud streets, convective liens/ filaments, decoupled layers & altocumulus) and modulate inversions and gradients? How are clouds physically linked to the top of the MABL and air/sea interaction at the ocean’s surface layer? How do clouds link the boundaries of the boundary layer?
Expected outcomes on fundamental principles include:
- Improved physical understanding of the cause and/or effect role of clouds in modulating boundary layer physics and dynamics, including air-sea energy exchange.
- New insight on the relationship between maritime cloud physics/properties and the complex combination of radiative, dynamic, microphysical and diffusion processes that foster the lower troposphere inversion.
- An understanding of how improvements in cloud physics can lead to better representation of the fundamental inhomogeneity in the properties and processes of the marine boundary layer.
- Production of a dataset suitable for model validations, leading to improvement of the forecast skills of high-resolution coupled models for boundary layer and cloud processes.
Request for Planning Letters
The first step in the DRI process is for prospective investigators to prepare planning letters. The purpose of the planning letters is to allow investigators to submit a short (three pages maximum) summary of their ideas on this topic for ONR to evaluate, provide technical feedback and indicate whether a full proposal would have a reasonable chance of success.
While the main window for lead proposals has closed, ONR will continue to consider supplemental or applied research projects. Refer to the current Marine Meteorology Planning Letter guidelines and indicate your desire to work with the MAGPIE project and team. Please note "MAGPIE Planning Letter ‘Your Last Name’" in your email subject line. If you do not receive acknowledged receipt within 10 days, please follow-up with a resend.
All planning letters should be submitted by email to the ONR Marine Meteorology team: Josh Cossuth (joshua.h.cossuth.civ@us.navy.mil), Kate Mulreany (katherine.l.mulreany.civ@us.navy.mil), and Dan Eleuterio (daniel.p.eleuterio.civ@us.navy.mil).