Brian M. Argrow - US grants

CTS-9902126
Brian Argrow/University of Colorado Boulder

Dense gases represent a fluid medium that displays novel properties, e.g. a rare faction shock wave, and potentially important technological attribute. Rankine cycle engines that exploit the non-classical behavior of these dense fluids are one example of the latter. The PI and his collaborators have carried out important initial investigations of these phenomena. The present award is to permit their construction and operation of a shock tube that will be used to investigate negative non-linearity in a single-phase vapor and to examine the properties of a rare faction shock wave.

Dense gases exhibit thermodynamic properties and gas dynamics behavior that can be significantly different from the low density (sp. gr. 10 -3) gases that are normally encountered. The proposed workshop will provide a welcome opportunity to permit a wide range of researchers to interact and to clarify the issues of consensus and the issues to which attention should be directed.

The project will develop an Arctic-capable aerosonde, design an instrument package for it, field test the instruments, and collect data in the Barrow, AK vicinity. The aerosonde is an autonomous aircraft that that builds on a design of a smaller platform that has flown in the Arctic. The improved aerosonde will be more robust and have increased navigational as well scientific instrumentation than its predecessor. The improved aerosonde will be able to fly over land and sea ice in order to make measurements of surface and near-surface properties that play a role in redistribution of heat in climate feedback systems. The remotely operated aerosonde also allows measurements to be made without the need of humans entering a very dangerous environment, particularly during the most hazardous time of the year. The aeorsonde will add an important access capability to Arctic research for a wide variety of atmospheric and surface properties studies.

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.

A field experiment will be conducted to probe an atmospheric airmass boundary with simultaneous dual-Doppler radars and in-situ sampling with a small Unmanned Vehicle System (UAS). The primary purpose is to develop techniques that will allow the fusing of weather radar data with UAS telemetry to navigate a small unmanned aircraft (UA) to a region of interest that is identified and tracked with weather radar. In addition to the technical challenges, the experiment must also address the evolving Federal Aviation Administration regulations to integrate small UAS into the National Airspace System (NAS).

Intellectual Merit:

This research activity will demonstrate the ability to navigate a small UA with an atmospheric sensor package into a transient mesoscale atmospheric phenomenon. Data from Colorado State University's NSF-sponsored CHILL and Pawnee radars will be fused with UAS telemetry to navigate the UA to a pre-existing atmospheric airmass boundary where in-situ data will be collected while the UA is controlled from its mobile ground station. This effort leverages technologies and experience developed at the University of Colorado's Research and Engineering Center for Unmanned Vehicles (RECUV). Atmospheric scientists from the University of Nebraska, Lincoln will direct the navigation and interpret the data.

Broader Impact:

The research program has the potential to add a valuable data acquisition tool for mesoscale dynamic meteorology and potentially provide an instrument that can provide thermodynamic data in regions of severe convective storms that have been difficult to sample. This potentially could lead to better storm forecasts.

This effort will create a new organization, Engineering for American Communities (EFAC) at the University of Colorado at Boulder to involve students in community-based projects for service learning. The role of EFAC, which in concept is a derivative of Engineers Without Borders, is to provide innovative and reasonably-priced design services for local, low-income customers aimed at creating significant impact on lives while being extremely affordable ? costing less than a single day?s pay. The products either result directly in an improved quality of life or provide customers with tools and solutions that might allow them to earn more money and attain a higher standard of living. This project represents an opportunity to conduct groundbreaking engineering education research to fully understand the impacts of altruistic engineering on student learning and attitudes, including commitment to engineering as a career. It integrates design for affordability throughout the K-16 engineering curriculum. Its ramifications will be assessed with a multitude of metrics, layered repeatedly throughout design activities. The investigation will develop an understanding of how participation in these activities changes student attitudes towards engineering, what students learn from participation, and whether the social context provided by these design activities may differentially recruit and retain students who have not traditionally been attracted to engineering.

The EFAC program provides powerful academic experiences for students in the University of Colorado at Boulder?s College of Engineering and Applied Science and its partner K-12 institutions, while building community with people in urban Denver and rural Colorado. This project seeks to discover how altruistic engineering affects a diverse audience of students and how to better prepare engineering students to meet the needs of a changing society. This model is replicable at almost any American university, where either an urban or a rural customer focus is within easy reach of its engineering students. It generates an opportunity to help U.S. citizens living below the poverty line, provides an innovative and unique learning situation for engineering students, and lays the framework for large-scale engineering education research with a cross-disciplinary set of set of researchers, teachers and learners.

The University of Colorado is establishing a Distributed Center for STEM Education Research and Transformation that integrates education projects across the campus. The Center addresses the three themes outlined in the National Academy of Science report "Rising Above the Gathering Storm". These are: (1) Teachers in K-12 education (10,000 Teachers, 10 Million Minds), (2) Research (Sowing Seeds), and (3) Higher Education (Best and Brightest). This Distributed Center involves eight traditional departments in three colleges and schools, including: Education, Life Sciences, Mathematics, Physical Sciences, and Engineering. Existing education projects being integrated into the center include: ADVANCE (Increasing the Participation and Advancement of Women in Academic Science and Engineering Careers); Course Curriculum and Laboratory Improvement projects; Robert Noyce Teaching Scholarship project; Integrative Graduate Education and Research Traineeship projects; and Research and Evaluation on Education in Science and Engineering projects.

The purpose of this project is to develop and utilize unmanned aircraft systems (UAS) to obtain critical meteorological observations aloft in the rear flank region of supercell thunderstorms. This is a pilot project with the initial emphasis being on the system development and obtaining experience in utilizing such systems in severe storm environments. If the pilot development project is successful, the Principal Investigators intend to participate in the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX 2). The investigators will utilize the expertise in unmanned aircraft operations of the University of Colorado to develop a system that is sufficiently safe to obtain a Certificate of Authorization for operation from the Federal Aviation Administration. Observations will be used to evaluate specific hypotheses related to the baroclinic generation of vorticity at the rear of the supercell updraft, and subsequent reorientation of that vorticity into the observed counter-rotating low-level vortices. The cyclonic member of this pair appears often to be the antecedent tornadic vortex.

Intellectual Merit
Supercell tornadogenesis is the result of a complex series of processes. Evidence suggests that the vorticity in a tornado originates as horizontal vorticity between the supercell updraft and a trailing rear flank downdraft (RFD). The RFD, in turn, appears to be partially the result of small-scale precipitation structures unique to supercells: the hook echo and/or a narrow descending reflectivity core. In some supercells, the vorticity generated between the major vertical drafts is drawn upward in the updraft, leading to arched vortex lines and associated counter-rotating vortices in the rear flank gust front convergence zone. Under certain conditions, that appear to be governed by the degree of negative buoyancy in the RFD, tornadogenesis can occur in the vicinity of the cyclonic member of the counter-rotating pair.

Broader Impacts
An important goal of this work is that it will contribute to the development of a rapidly-deployable mesoscale and stormscale UAS sensing system. The system will be suitably designed to greatly reduce regulatory hurdles to its future deployment. Important knowledge will be gained on technical and regulatory issues that will allow future deployments of UAS for weather research.

Collected observations will improve understanding of RFD buoyancy and tornado cyclone genesis. This information may lead to improvements in the tornado warning process via the diagnosis of rear-flank precipitation morphology and hydrometeor structure using Doppler radars with dual-polarization diversity capability. Further, it is anticipated that RFD buoyancy can be estimated through knowledge of the low-level thermodynamic stratification. Eventually, it is likely that operational meteorologists can make much better discriminations between potentially tornadic and non-tornadic supercells.

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.

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.

This award will provide funding for participation in a small field project making use of unmanned aircraft systems (UAS) for atmospheric observations. UASs are attractive platforms for atmospheric scientists due to their ability to fly into regions where other observation systems can?t, such as under the base of a supercell thunderstorm. This award will allow researchers the opportunity to compare four different small UASs and their instrument payloads. This work has broader impact through the development and testing of new technologies which will help to improve the understanding of atmospheric processes and the capability to forecast weather and climate.

The project will take place at the Boulder Atmospheric Observatory (BAO) in Colorado. The four UASs will be flown near the instrumented BAO tower and also in the range of the Colorado State University CHILL radar and the Texas Tech University Ka-band mobile radar. This will allow the researchers the opportunity to compare the UASs against proven, ground-based measurements. The second step will be to fly all four of the UASs on a target of interest, such as a cloud or a thunderstorm. The data will be used to refine the current systems and as a benchmark for the development of future systems.

This project addresses the development of self-deploying aerial robotic systems that will enable new in-situ atmospheric science applications. Fixed-wing aerial robotic technology has advanced to the point where platforms fly persistent sampling missions far from remote operators. Likewise, complex atmospheric phenomena can be simulated in near real-time with increasing levels of fidelity. Furthermore, cloud computing technology enables distributed computation on large, dynamic data sets. Combining autonomous airborne sensors with environmental models dispersed over multiple communication and computation channels enables the collection of information essential for examining the fundamental behavior of atmospheric phenomena. The aerial robotic system proposed here will close significant capability gaps in conventional platform's abilities to collect the data necessary to answer a wide range of scientific questions. The motivating application for this work is improvement in the accuracy and lead-time of tornado warnings.

The proposed project draws on techniques in the areas of robotics, unmanned systems, networked control, wireless communication, active sensing, and atmospheric science to realize the vision of bringing cloud robotics to the clouds. The autonomous self-deploying aerial robotic systems is comprised of multiple robotic sensors and distributed computing nodes including: multiple fixed-wing unmanned aircraft, deployable Lagrangian drifters, mobile Doppler radar, mobile command and control stations, distributed computation nodes in the field and in the lab, a net-centric middleware connecting the dispersed elements, and an autonomous decision-making architecture that closes the loop between sensing in the field and new online numerical weather prediction tools.

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).

Storm-generated boundaries are the focal point for tornadogenesis. As such, a more complete understanding of boundary and gust front structure in supercells is required to advance understanding of the processes responsible for supporting or obstructing the concentration of near-surface rotation. Targeted Observation by Radars and UAS of Supercells (TORUS) aims to improve the conceptual model of supercells by explicating the relationship of storm-generated boundaries and coherent structures within storm outflow to the generation/amplification of near-surface rotation. New insight will be enabled through coordinated and tightly-focused deployments of new and established remote-sensing and in-situ instruments tasked to collect thermodynamic and kinematic observations both aloft and at the surface.

Intellectual Merit:
Hypothesized mechanisms for tornadogenesis move beyond a focus on just the canonical rear-flank and forward-flank gust fronts and also address the role of boundaries and coherent structures recently revealed in observational and numerical analyses of supercell tornadoes. Accurate identification of these roles will advance the frontiers of knowledge and transform the conceptual model of supercells. Overarching objectives are to 1) expose the 4D character of these boundaries and coherent structures, 2) relate the 4D character of these boundaries and coherent structures to the thermodynamics and kinematics of supercell outflow, 3) associate boundary and coherent structure characteristics to ensuing contraction or failed contraction of near-surface vertical vorticity beneath low-level mesocyclones, and 4) and relate these characteristics to the ambient conditions within which storms reside.

The TORUS field campaign will be executed across 42 days of deployments spanning two spring seasons (May-June 2019 and 2020) over an operations domain covering ~1,300,000 km2 of the central US. Observing platforms involved in TORUS include four unmanned aircraft systems, two mobile Ka-band radars, seven mobile mesonets, one mobile X-band radar, and one mobile sounding systems. Assets will be deployed to focus data collection in different parts of storms.

Broader Impacts:
TORUS will promote teaching, training, and learning by involving ~40 students in the project's field deployments. At least three graduate students will use the data collected during the TORUS field deployments for their thesis research. Undergraduate students will also have opportunities to use TORUS data for mentored research projects. TORUS data will be integrated into undergraduate and graduate courses taught by the PIs. TORUS research will also provide students the opportunity to attend and present at national conferences in atmospheric science and aerospace engineering. TORUS will enhance infrastructure for research and education by codifying collaborations between the University of Nebraska-Lincoln, Texas Tech University, the National Severe Storms Laboratory, and the University of Colorado-Boulder and by supporting the refinement of cutting-edge instrumentation. Results from TORUS will be broadly disseminated in an effort to enhance scientific and technological understanding. This will include publication in peer-reviewed journals, presentations to local and regional groups (e.g., K-12 schools, museums, etc.), and seminars at participating institutions and elsewhere. Direct interaction with the operational forecasting community will also be sought (e.g., via local National Weather Service Forecast Offices) so that these results can be expediently and effectively disseminated to operational forecasters.

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.

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.

This project will conduct innovative integration of robotics technologies to create Marsupial Aerial Robot Teams (MARTs) whereby small uninhabited aircraft systems (i.e. drones) carry smaller aircraft to provide observations of the atmosphere. Effective advanced warning systems enabled by the data collected by MARTs could drastically reduce the loss of life and damage caused by severe weather. Aerial robotic systems operating in places too dangerous for humans or expensive single-vehicle systems will need to reason over detailed models and large amounts of data. This project will create and deploy a team of robots that will be like an autonomous airborne meteorologist performing online targeted forecasting.

MARTs achieve the National Robotics Initiative’s goal to promote the integration of robots to the benefit of humans. This project will develop an autonomous airborne meteorologist that consists of teams of aerial robots connected to dispersed users and computing resources. The effort embodies the theme of innovative integration of robotic technologies by advancing current practices through new fundamental algorithms integrated, deployed, and evaluated on marsupial aerial robot teams. Integrated robotic technologies include: i.) air-launched pseudo-Lagrangian drifters; ii.) ensemble sensitivity analysis for autonomous targeted observation; iii.) algorithms that solve online continuous-domain partially-observable Markov decision processes (POMDPs); iv.) parallelized path planning in uncertain flows; and v.) a dispersed autonomy architecture for marsupial aerial robot teams.

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.