Dale A. Lawrence - US grants

This project investigates combined visual and haptic (touch) interfaces to display multi-dimensional data generated by computer models of physical systems. The focus is on data features that are difficult to convey visually, such as scalar data which fills volumes, vector fields, and tensor fields. First, tests are conducted to better understand the perception of haptic rendering elements: virtual surfaces and constraints, forces and torques, and mechanical impedances. Second, new haptic rendering modes are developed which can convey multi- dimensional data via combinations of haptic rendering elements. These modes are tested using representative visualization problems in fluid dynamics, electromagnetics, and solid mechanics. Third, visualization puzzles are developed which quantify the perceptual added value of haptic rendering modes. Both cooperative and complementary visual/haptic rendering are explored. The project seeks to discover synergistic rendering modes which produce understanding more easily than visual rendering alone. An improved visual/haptic interface enables intuitive debugging of computer models, efficient visualization of modeling results, and improved physical understanding. Such a capability benefits the conduct of scientific research in many fields, the design and analysis of engineered systems, and the education of future scientists and engineers.

Proposal # HRD-0095944
Institution: University of Colorado at Boulder
Principal Investigators: Lucy Y. Pao, Dale A. Lawrence, and
Howard Kramer
Title: "Haptic Interfaces for Spatial Learning"

ABSTRACT

This project will explore the use of haptic (touch) interfaces, in concert with conventional visual and audio interfaces, to enhance communication and learning of spatial concepts in science and engineering. Graphical means of expressing spatial concepts provide the most clear and concrete representation of spatial ideas, but are often the most difficult for people to use. In contrast to existing approaches that use only vision, the project will seek non-visual means of expressing and communicating spatial ideas and data. The approach also differs from recent attempts to reproduce 2D visual graphs or pictures as 2D haptic or tactile artifacts for the visually impaired. Such approaches depend on projections of 3D objects onto viewing planes, a technique that is only marginally accessible to blind people.

Technology exists that can enable people to draw effectively in 3D without depending on vision or vision-like projections of the 3D object or idea. The project will explore the integration of a 6 degree of freedom (DOF) haptic interface with new software tools that produce a variety of direct 3D drawing capabilities, including the capability to instantly review and correct the concept as it is created. Investigators will explore the benefits of non-visual (haptic and audio) feedback for drawing. We believe non-visual interaction with drawing tools can make graphical representations of spatial constructs, relationships, and ideas much easier to generate and share, promoting clearer discourse in fields that depend on spatial concepts. The ability to create precise 3D drawings would provide a mode of communication for visually impaired people opening new opportunities in fields that require an ability to communicate using spatial representations.

The technology to be developed and test consists of a desktop workstation that provides capability for visual, audio, and haptic interaction with computer-generated spatial constructs. The tools will consist of software programs that allow users to easily draw in 3-dimensions with visual, haptic, and audio feedback. A suite of rendering/drawing modes will also be developed to enable users to create and interpret 3-dimensional objects or drawings.

The existing visual/haptic interface facility at the University of Colorado will be augmented with audio capabilities similar to those currently used in the University of Colorado Assistive Technology Lab. This augmented workstation will be used as a testbed during years 1 and 2 of the project, where work will focus on the development and testing of particular modes of drawing and rendering spatial objects and data, and of particular pedagogic approaches to learning spatial concepts. The resulting rendering modes will be evaluated by students with learning and/or visual impairments as well as non-impaired students who are interested in science and engineering.

Proposal Number: 0427947
PI: Kamran Mohseni
Institution: University of Colorado, Boulder
Title: ITR - Loosely Cooperating Micro Air Vehicle Networks for Toxic Plume Characterization

Abstract:

Release of contaminants in urban areas can lead to severe public health consequences. This project develops an integrated Sensor Flock to enable rapid characterization of toxic plumes for contamination prediction and source location. A Sensor Flock consists of semi-autonomous micro air vehicles (MAVs) transporting miniature toxin sensors throughout the atmosphere above populated areas, networked to a base station providing toxin dispersion modeling and flock supervision, using novel lightweight, real-time, data-reactive wireless information routing. MAV platforms lower manufacturing costs, reduce risks of collision damage, and reduce visibility and noise that might create public alarm.

The concept of Information Energy is introduced to tightly integrate advances in three interdisciplinary areas: aerodynamics, networking, and control. This enables high-quality information products from the Sensor Flock, using relatively simple individual vehicles. The MAVs are designed based on biomimetic principles of bat flight to enable exceptional flight performance. Vehicle control is based on a hierarchical information energy formulation, producing simple gradient-descent guidance laws on each vehicle, but with well-understood flock clustering behavior toward regions of high-quality data. The behavior of data-driven routing in each of the following three communication scenarios is investigated: inter-MAV exchange of high-quality data for flock convergence; MAV-to-ground collection of sensor data; and ground-to-MAV command and control.

Existing disciplinary courses at CU Boulder are enriched with results from this work, expanding student multidisciplinary exposure. A summer Aerobotics program enables local high school students to participate in a design/build/fly competition integrating computer science and aerospace engineering.

Funds are provided for the development, testing, and deployment of a low-cost laser profiling system that can be operated onboard small unpiloted aerial vehicles (UAVs), and that is capable of serving as a component of a widely distributed and long-term monitoring and observation program, such as may be established for the International Polar Year. As part of this development, data analyses sufficient to test the ability to extract basic sea-ice parameters, such as roughness and freeboard, from laser profiles flown over the Arctic sea ice near Barrow, Alaska will be included. Using basic analysis techniques such as comparisons of roughness with other data sets (MODIS ice products and satellite SAR and scatterometer imagery), these data should suffice to yield substantial insights into variations in ice conditions. While the focus of this effort is on improved understanding of sea ice, the proposed laser profiling system and analysis techniques are applicable to many other research uses, e.g. mapping changes in ice sheets and glaciers, vegetation canopy studies, monitoring shoreline change, and surveying ocean wave heights.

[unreadable] DESCRIPTION (provided by applicant): [unreadable] Lung cancer is the leading cause of cancer deaths in the United States, causing more deaths than breast, prostate and colorectal cancer combined. Some progress has been made in reducing lung cancer mortality, however, progress has been slow and hampered by the lack of effective early detection strategies. New, cost-effective techniques are needed to screen, localize, sample, and treat suspicious lesions. Bronchoscopy is a proven method of visualizing the airways of the lung and performing biopsies of suspicious tissue. While the bronchoscope has proven to be a very valuable tool, it has not yet lived up to its full potential since its size precludes access to more than half of the lung. In response to the current limitations of bronchoscopy, Rose Biomedical Development Corporation and its partner the University of Colorado, propose developing and testing the MicroFlex Scope, an innovative 1 mm diameter, highly dexterous extension of current bronchoscopes to support early detection of lung cancer in a greater area of the lung. The team proposes developing and testing the technology during the Phase I proof of concept. In Phase II, the prototype scope will be built and in vivo testing conducted. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Chronic sinusitis affects approximately 33 million Americans each year, and has become one of the most prevalent chronic diseases. Because of its-persistent nature, chronic sinusitis is a significant cause of morbidity and represents considerable expense to the health care system. In 2001, approximately 200,000 sinus surgeries were performed in the U.S. Access, visualization, and surgical technique all factor into patient safety and the ability to minimize complications in this challenging anatomical area with close proximity to sensitive orbital and cerebral structures. Currently, endoscopes, and related instrumentation do not provide the flexibility to access, directly visualize, and effectively perform sensitive procedures in all sinus structures. Rose Biomedical Development Corporation (RBDC), and its partners at the University of Colorado, propose developing and testing the MicroFlex Scope (MFS), an innovative 3 mm diameter, highly dexterous scope that would extend access to all areas of the nasal sinuses for direct visualization and treatment. The MFS will allow safe navigation and direct visualization through the highly flexible and dexterous MicroFlex technology. It will facilitate accurate diagnostics, effective tissue sampling and sinus treatment through MFS's actively-controlled tip with enhanced controllability supporting 360x of freedom via actuators in the ultra-flexible tip.

DESCRIPTION (provided by applicant): MicroFlex technology will provide unprecedented flexibility and controllability for the tip of endoscopes, enabling minimally invasive surgery in previously inaccessible spaces, direct visualization of structures there, and fine tool manipulation capabilities for diagnostic, therapeutic and surgical procedures. MicroFlex combines innovations in actuation, sensing, control and assembly to produce a 3mm diameter digitally or robotically controlled endoscope more flexible and controllable than those currently available. This project will use technology proven in the Phase I study to fabricate and functionally test MicroFlex prototypes for sinus diagnosis and surgery. MicroFlex prototypes will be assembled and tested in the laboratory for force and motion capabilities, a control manipulative and associated control electronics and software will be developed, and rhinologists will test the integrated system in cadavers for function and usability. Since the MicroFlex tip is controlled by temperature change in internal actuator elements, thermal effects on surrounding tissue will be assessed in detail, including advanced engineering models for temperature distribution and live animal testing for thermal damage. Sterilization robustness and effectiveness of a prototype device will also be tested. MicroFlex technology, fabrication processes and prototypes will be refined by integrating input from practicing sinus surgeons, engineers with expertise in medical product design, and prospective Phase III manufacturing partners and suppliers of complementary navigation and visualization technology. Potential Phase III manufacturing partners will be identified and utilized for Phase II prototype components, where possible, to accelerate the commercialization process. MicroFlex Tools to Improve Sinus Diagnostics and Surgery

Planning Grant for an I/UCRC for Unmanned Aircraft Systems

0968950 Brigham Young University; Tim McLain
0968991 University of Colorado at Boulder; Brian Argrow

The Center for Unmanned Aircraft Systems (CUAS) will investigate and develop new algorithms, architectures, and operational procedures for unmanned aircraft systems. Brigham Young University (BYU) and the University of Colorado at Boulder (UCB) are collaborating to establish the proposed center, with BYU as the lead institution.

Since the development of UAS is critical to national security CUAS aims to be the focal point for storing and disseminating information about UAS of all sizes, from micro to large. The proposed Center has identified some of the challenges to overcome in order to establish UAS dominance in the US. The research led by the Center will lead to new concepts, technologies, insights, and tools for UAS. BYU and UCB plan to use the NSF planning grant fund to hold a meeting with prospective industrial partners to establish the proposed Center?s organizational framework, and to establish research projects of greatest relevance.

The broader impacts of the Center include curriculum design, community outreach and training the next generation of UAS researchers. BYU and UCB will work with industry and government sponsors to provide opportunities to students to work on high-impact, cutting-edge research. The Center also plans to attract women and under-represented minority groups as students in the Center.

This is a 3-year project to undertake experimental and theoretical studies of Kelvin-Helmholtz Instability (KHI) dynamics and their implications for turbulence and mixing in the Earth atmosphere. KHI is known to occur throughout the lower atmosphere as well as the mesosphere and lower thermosphere (MLT) and to contribute significantly to the dynamics. In addition, KHI evolution affects VHF Doppler radar wind measurement errors by producing strong, persistent layering and a systematic tilting of refractive index surfaces on scales comparable to VHF radar Bragg scales. This project addresses both of these aspects. Observations will be performed at the Jicamarca Radio Observatory (JRO) in Peru, which provides an exceptional combination of sensitivity and resolution throughout the lower atmosphere and the MLT. High range resolution and sensitivity at mid-tropospheric heights provided by the SOUSY Radar (at JRO), coupled with concurrent, quantitative, high-resolution, in situ measurements made using a newly developed unmanned aerial system, named the micro-autonomous vehicle (MAV), will provide an unsurpassed assessment of both high resolution KHI dynamics and radar measurement errors. The relatively high-resolution and higher-power capability provided by the powerful JRO transmitter and large antenna array will then extend the SOUSY results into the MLT. Finally, these observations will be used to initialize a series of numerical assessments of KHI radar backscatter and associated dynamical parameters using a new capability to perform direct numerical simulations (DNS) to characterize, and guide corrections of, measurement errors accompanying these dynamics for general flow conditions.

The inaccuracies in radar wind measurements from KHI is a limiting factor in understanding atmospheric dynamics on essentially all scales of motion, including: mean motions, wind shears, large-scale tidal and planetary wave activity, smaller-scale gravity wave dynamics, and small-scale instabilities and turbulence-generating processes. The results from this project, therefore, will improve practically all applications of VHF radar observations to great benefit of the scientific community as well as weather and climate modeling applications. The project also will result in improved quantitative understanding of interactions between waves and instability dynamics that drive motions throughout the atmosphere and at all scales. This will lead to better parameterization of small-scale dynamics in weather and climate models.

DESCRIPTION (provided by applicant): MicroFlex Technology for Early Detection of Lung Cancer Project Summary MicroFlex technology will provide unprecedented flexibility and controllability for bronchoscopes, enabling minimally invasive bronchoscopy to reach previously inaccessible peripheral bronchi and provide direct visualization and tool manipulation capabilities for diagnostic and therapeutic procedures. MicroFlex technology combines innovations in actuation, sensing, control and assembly to produce an ultra-slim digitally controlled bronchoscope more flexible and controllable than currently possible. This technology promises to improve detection, for example of early-stage lesions, and provide more accurate diagnoses to improve cure rates for lung cancer and other lung diseases. This project will refine technology proven in the Phase I study to design, fabricate and functionally test novel 1mm diameter actively-guided MicroFlex Tool prototypes for bronchoscopy procedures. A lung-specific MicroFlex device will be developed, built and tested in the laboratory for force and motion capabilities, a control manipulative and associated control electronics and software will be developed, and pulmonologists will test the integrated system in-vivo in animals for function and usability. Since MicroFlex tools are controlled by temperature change in internal actuators, thermal effects of contacting bronchial epithelial tissue will be studied for thermal tissue damage and validation of thermal control models. Effectiveness of a prototype MicroFlex device including a Guide Catheter and MicroFlex Tool will be evaluated in accessing peripheral sites down to a 1mm bronchiole diameter, visualizing tissue, placing markers and performing tissue sampling. MicroFlex technology, fabrication processes and prototypes will be refined by integrating input from experienced bronchoscopists, engineers with expertise in medical product design, and prospective Phase III manufacturing partners and suppliers of complementary technology. Potential Phase III manufacturing partners will be identified and utilized for Phase II prototype components, where possible, to accelerate the commercialization process.

I/UCRC for Unmanned Aircraft Systems (UAS)

1161036 Brigham Young University; Tim McLain
1161029 University of Colorado at Boulder; Eric Frew

The Center for Unmanned Aircraft Systems (CUAS) will investigate and develop new algorithms, architectures, and operational procedures for unmanned aircraft systems. Brigham Young University (BYU) and the University of Colorado at Boulder (UCB) are collaborating to establish the proposed center, with BYU as the lead institution.

The development of UAS is critical to national security, and CUAS aims to be the focal point for discovery and disseminating information about UAS of all sizes, from micro to large. The proposed Center has identified some of the challenges to overcome in order to establish UAS dominance in the US. The research led by the Center will lead to new concepts, technologies, insights, and tools for UAS; and will facilitate the transfer of these ideas to industry. The proposed center will contribute to the advancement of the UAS community through cutting-edge, industrially relevant research at the center's universities and by training the next generation of technical leaders inn the UAS field.

The broader impacts of the Center include curriculum design, community outreach and training the next generation of UAS researchers. BYU and UCB will work with industry and government sponsors to provide opportunities to students to work on high-impact, cutting-edge research relevant to industry and government labs. The Center also plans to attract women and under-represented minority groups as students in the Center. The center plans to have a significant impact on UAS curriculum through course design, textbooks, laboratory exercises, and senor design experiences.

The vertical structure of the free atmosphere under stable conditions from very low altitudes into the stratosphere and above is often characterized by thin, strongly stable, non-turbulent "sheets" separated by thicker, more weakly stratified, and often turbulent "layers". The occurrence and morphology of "sheet-and-layer" (S&L) structures in the free atmosphere are believed to be governed by larger-scale wind shears, gravity waves (GWs) at various frequencies, local S&L instability dynamics, turbulence and mixing, and their interactions.

S&L structures have been known for several decades to play important roles in optical and radiowave propagation and in transport and mixing of heat, momentum, and constituents. There is also evidence that these small-scale flow features can have important implications for larger-scale dynamics, including instabilities and momentum transport accompanying GWs propagating to higher altitudes. However, little progress has been made in understanding the underlying dynamics or addressing the roles of instabilities and turbulence, the interactions among them, or the consequences of these flows for transport and mixing. In particular, the sources, morphologies, and statistics of intermittent turbulence events in stable stratification, and their dependence on environmental conditions remain to be defined observationally (e.g., instability character and statistics of S&L thicknesses, turbulence structure parameters and scales, and mechanical and thermal energy dissipation rates).

Our lack of understanding of these dynamics to date can largely be attributed to observational and computational challenges in capturing the relevant atmospheric structures and dynamics with sufficient spatial and temporal resolution. The research program IDEAL, Instabilities, Dynamics, and Energetics accompanying Atmospheric Layering will conduct ground-based and in-situ measurements and associated modeling combined to quantify these processes and provide key insights into S&L dynamics and effects throughout the stratified atmosphere. The IDEAL will perform measurements either at Dugway Proving Ground (DPG) in Utah or at Camp Guernsey Joint Training Center (CG) in Wyoming, where restricted airspace is already assured.

Intellectual Merit:
For the first time, the dynamics underlying ubiquitous S&L structures in the free troposphere will be observed with multiple, coordinated, high-resolution, in-situ sensors together with the integrated sounding radar profiler and radiosondes from ~50 m to 4 km. Guidance and interpretation of the observations will be aided by high-resolution DNS, enabling identification of key dynamics and evaluation of theories and models of stratified turbulence, mixing, and transport.

Broader Impacts:
A more quantitative understanding of S&L dynamics in the stably stratified atmosphere will contribute to parameterization of their implications for transport and mixing and improve predictive capabilities of relevance to many research communities. These include applications as diverse as pollution and fugitive emission impacts, micro-climate forecasting, and aviation safety. The project will train two graduate students in state-of-the-art studies in atmospheric science, aerospace engineering, and computational fluid dynamics. Measurement technologies and techniques developed in this work will benefit future field research campaigns and regulatory compliance mandates.

The Center for Unmanned Aircraft Systems (C-UAS) addresses the issues common to the unmanned aircraft system (UAS) industry that limit widespread application across national security, scientific, civil, and commercial domains. Research within the UAS industry is driven by both technical gaps existing for specific high-value applications and the current under-developed regulatory framework that is needed for integration of UAS into the national airspace. The full value of unmanned aircraft systems, especially for a broad range of scientific and civil applications, cannot be realized without significant multidisciplinary research efforts such as those proposed here. Toward that goal, C-UAS investigates and develops new algorithms, architectures, and operational procedures for unmanned aircraft systems. The center contributes to the advancement of the state of the art for UAS through its research at the center's universities and by training graduate students in areas supporting the advancement of UAS.

The research pursued in C-UAS has potential application to unmanned aircraft of all sizes. The primary focus of research activities, however, is on small unmanned aircraft systems (SUAS), which feature aircraft with wingspans in the 1 ft to 8 ft range. C-UAS university sites have distinguished themselves with their experimental flight test demonstrations on these smaller platforms. The research interests and needs of industry in the area of UAS align well with the skills, knowledge, and background of the university participants in the center. Research focus areas for the University of Colorado Boulder site can be described in terms of (1) technical areas and (2) application areas. Technical topic areas in which the University of Colorado has particular strength and interest include: (i) Airborne communication networks and network-enabled autonomy (e.g., methods for routing data through mobile ad-hoc networks and for accessing dispersed computing), (ii) environmental sensing (e.g., novel sensor development and planning algorithms for targeted observation of environmental phenomena), (iii) human-autonomy interaction (e.g., natural language interfaces and humans-as-sensor models for communication of spatial information), (iv) assured autonomy and user trust (e.g., measures of machine self-confidence and assessment of their impact on user trust), (v) UAS traffic management (e.g., investigating the impact of weather on small UAS operations), and (vi) guidance and control with in complex winds (e.g., implementing control algorithms for wind gust disturbance rejection or for energy harvesting). Application topic areas in which the University of Colorado has particular strength and interest include: (i) Atmospheric science with emphasis on severe weather, (ii) Cooperative distributed sensor fusion and target tracking, and (iii) Search and rescue. Specific research projects proposed by University of Colorado faculty members in these technical and application areas are selected annually by the Industry Advisory Board (IAB).

This study will use an emerging technology, unmanned aircraft systems, to collect measurements with the goal of improving weather and climate models of the Arctic system. It is part of the international MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) program, an extensive field effort to freeze an icebreaker into sea ice for an entire year to serve as a research platform for a comprehensive study of the atmosphere, ocean and ice system in the high Arctic. The unique and potentially transformative aspect of this project is that unmanned aircraft collect data at small spatial and temporal scales, providing new information about variability in temperature, humidity, and winds. In addition, direct measurements of these variables over breaks in the sea ice have been very limited to date. Therefore, this study will address a significant source of error in our current ability to forecast how energy is transferred between the atmosphere and underlying ice and sea surface. Together with information from collaborating scientists participating in the MOSAiC field effort, the investigators will evaluate a series of hypotheses related to the performance of model simulations of key processes over the central Arctic Ocean. The investigators will also give pubic lectures at schools and other venues, capitalizing on interest and excitement in use of new technology though use of videos and photos of the unmanned aircraft systems. They will support training for early career scientists by involving graduate students and postdoctoral scientists.

The investigators will deploy an unmanned aircraft system to measure atmospheric temperature, winds, and humidity, as well as surface albedo. Flights will take place from mid-winter (February) through late summer (August) to capture variable conditions in both the atmosphere and sea ice surface and will include routine profiling of the lower atmosphere, spatial mapping of thermodynamic quantities and surface albedo, and mapping of the lower atmospheric structure over leads. This data will be evaluated with measurements of the atmosphere, ocean and ice collected by other scientists as part of the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) project to address hypotheses related to the performance of modeling tools in simulating key processes over the central Arctic Ocean. These include questions about sub-grid scale variability of atmospheric and surface parameters and its influence on model-simulated surface energy budget; the influence of leads in the sea ice on energy transfer from the ocean to the atmosphere and how models represent this transfer; and the importance of vertical resolution in simulation of the Arctic atmosphere and its impact on the simulation of clouds and the surface energy budget. The investigators will compare observations from unmanned aerial systems to a variety of simulations, ranging from global products to fully-coupled regional simulations completed using the Regional Arctic System Model (RASM) to detailed single-column and 2D modeling at high resolution.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Understanding the temperature structure of the upper ocean in the Arctic is very important for properly simulating the formation and melt of sea ice in climate and weather models. The presence (or absence) is important for a variety of activities, including shipping, energy exploration and hunting by native populations. Therefore, forecasting the presence of ice at shorter timescales is critically needed. Sea ice additionally has a controlling influence on climate by acting as a bright surface capable of reflecting sunlight back to space, thereby highlighting a need to accurately forecast it on decadal time scales. A significant source of errors in forecasts at all scales is the ability to predict to what extent mixing of the upper ocean occurs and how this mixing helps to eliminate gradients in temperature and salinity that might change the rate of ice formation or melt. An important item to understand is to what extent atmospheric winds, which we generally forecast relatively well, contribute to this upper-oceanic mixing through the transfer of energy between the atmosphere and ocean. This project will support the collection of key measurements necessary to help inform the improvement of weather and climate models to support prediction of sea ice at a variety of time scales.

In this study, an unmanned aircraft system will be deployed to provide measurements of atmospheric temperature, winds and humidity. This information will be used together with information from surface buoys and ice imagery to understand atmosphere-ocean energy transfer during the fall freeze-up period. Specifically, this work will help to address questions related to the role of the presence of sea ice in energy transfer and how that role is simulated in numerical models, the extent to which mechanisms supporting transfer vary at small spatial scales and how those are handled in today?s state of the art modeling tools, and the importance of vertical resolution of models in accurately capturing this energy transfer. Measurements will be compared to high-resolution models that couple the atmosphere, ice and ocean together into single simulations. Flights will take place from northern Alaska in September and October of 2018 and will interface with a broader effort (the Stratified Ocean Dynamics of the Arctic, or SODA, project) to understand the upper ocean in this part of the world. Additionally, this work will interface with the ongoing Year of Polar Prediction, providing extra connections to the modeling communities who can benefit from these measurements.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

The project seeks funding to investigate atmospheric turbulence generation. Shear layers in the atmosphere, where a layer slides over another, can result in instabilities that are commonly seen in thin cloud layers and resemble a series of ocean waves breaking on a beach. These instabilities, called Kelvin-Helmholtz instabilities, cause turbulence and mixing throughout the atmosphere and the oceans where shears are strong. Spacing between these “billows” can vary in the atmosphere from a few meters near the ground to 10 km or larger at altitudes as high as 100 km. Those seen in clouds usually have spacings (or wavelengths) from a few hundred meters to a km or so. The turbulence and mixing when these billows “break” influence the atmospheric structure and weather, especially near the ground, but their effects are not described well in weather prediction models. This research will explore a new type of instability causing breaking and turbulence that was recently discovered in thin clouds at very high altitudes that the research team expects to occur at all altitudes, and to significantly increase the turbulence and mixing due to these processes. If shown to occur for a wider range of conditions, this would significantly influence our ability to model the atmosphere near the ground and improve weather prediction that impacts all of us. The same instabilities occur in the oceans and are expected to also improve prediction of ocean circulations and structure when these processes are more fully understood. The project will involve a graduate student and a postdoctoral researcher experience in state-of-the-art modeling and super-computing.

New observations of thin Polar Mesospheric Clouds and airglow layers at high altitudes (~80-90 km) have revealed the occurrence of a new type of instability leading to turbulence arising from mis-aligned Kelvin-Helmholtz (KH) billows accompanying variable geophysical forcing. These instabilities arise due to interactions among adjacent KH billow cores, rather than within single billows, and initial modeling of these dynamics have shown them to be much stronger, and to lead to much more intense turbulence, than occur in their absence. These dynamics arise from interactions between KH billow cores and large-scale vortex tubes that are excited where KH billows are mis-aligned or discontinuous due to initial conditions. Initial modeling employing direct numerical simulations that enable quantitative assessments of these dynamics, their stronger instabilities, and their more intense turbulence suggest that they may also cause enhanced turbulence and mixing in regions, and for conditions, in which turbulence was not previously expected. The research team believes that these enhanced KH billow dynamics are likely to be widespread and that they will allow us to update how these dynamics are modeled, enabling improved weather prediction, and of similar responses in the oceans. Because KH instabilities also play significant roles of other fields of physics, specifically magnetospheric physics and astrophysics, the benefits of this research may prove to be very broad.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.