Physical Sciences and Mathematics Commons^™

Observations Of Reduced Turbulence And Wave Activity In The Arctic Middle Atmosphere Following The January 2015 Sudden Stratospheric Warming, Colin C. Triplett, Jintai Li, Richard L. Collins, Gerald A. Lehmacher, Aroh Barjatya, David C. Fritts, Et. Al.

Publications

Measurements of turbulence and waves were made as part of the Mesosphere-Lower Thermosphere Turbulence Experiment (MTeX) on the night of 25–26 January 2015 at Poker Flat Research Range, Chatanika, Alaska (65°N, 147°W). Rocket-borne ionization gauge measurements revealed turbulence in the 70- to 88-km altitude region with energy dissipation rates between 0.1 and 24 mW/kg with an average value of 2.6 mW/kg. The eddy diffusion coefficient varied between 0.3 and 134 m²/s with an average value of 10 m²/s. Turbulence was detected around mesospheric inversion layers (MILs) in both the topside and bottomside of the MILs. These …

On The Asymmetry Between Upward And Downward Field-Aligned Currents Interacting With The Ionosphere, A. V. Streltsov

Publications

The paper presents results from the numerical study of the magnetosphere-ionosphere interactions driven by the large-scale electric field in the magnetically conjugate, high-latitude regions of northern and southern hemispheres. Simulations of the two-fluid MHD model demonstrate that these interactions can lead to a generation of a system of small-scale, intense field-aligned currents with a significant difference in size and amplitude between the upward and downward currents. In particular, in both hemispheres, the downward currents (where the electrons are flowing from the ionosphere) become more narrow and intense than the adjacent upward currents. At high latitudes, the field-aligned currents are closely …

On The Existence Of Ionospheric Feedback Instability In The Earth’S Magnetosphere-Ionosphere System, Anatoly V. Streltsov, Evgeny V. Mishin

Publications

The ionospheric feedback instability (IFI) has been considered one of the main generation mechanisms for large-amplitude ultralow frequency waves and small-scale field-aligned currents in the auroral and subauroral regions for more than 40 years. Sydorenko and Rankin (2017, https://doi.org/10.1002/2017GL073415) have recently challenged the very existence of the IFI for any realistic geophysical conditions in the Earth's ionosphere-magnetosphere system. Because this conclusion contradicts numerous theoretical, numerical, and experimental works successfully used IFI to explain and predict results from observations for more than four decades, it deserves special attention. We show that this conclusion is mainly based on the specific ionospheric …

Challenges For Flight Instructors Teaching Weather Information, Robert Thomas, Thomas A. Guinn

Aviation Weather Training Research

• Flight Instructors face a challenge when teaching/learning weather information
• Multiple overlapping resources for aviation weather
• AC takes longer timeframe to update –problem for quick updates of information

Assessing Ga Pilots' Preflight Weather Planning Mental Models, Yolanda Ortiz, Beth Blickensderfer, Thomas A. Guinn

General Aviation Weather Display Interpretation

Purpose, To assess GA Pilots' ability to:

• Obtain the Appropriate Weather Information
• Interpret the Data
• Apply the Information to a Given Flight Route

Interpreting Aviation Weather Products: Follow-Up Study With Aopa Members, Beth Blickensderfer, Thomas A. Guinn, Thomas Bob, Jayde King, Yolanda Ortiz, Nick Defilippis, Quirijn Berendschot, Jacqueline Mcsorley

General Aviation Weather Display Interpretation

Purpose

• Use the questions we developed in Phase I
• Include pilots that are more representative of GA (age, flight hours/experience); Collaborate with AOPA
• Examine: Knowledge about aviation weather products; Differences between levels of flight certificate and/or ratings

Aviation Weather Education: Challenges Using Current Faa Guidance, Thomas A. Guinn, Robert Thomas

Aviation Weather Training Research

Observed Challenges

• Incorrect product information
• Guidance not keeping pace with new products
• Multiple formats of same product
• Potentially unnecessary information
• Missing product information
• Limited focus on interpretation

Momentum Flux Spectra Of A Mountain Wave Event Over New Zealand, Katrina Bossert, David C. Fritts, Christopher J. Heale, Stephen D. Eckermann, John M. C. Plane, Jonathan B. Snively, Bifford P. Williams, Iain M. Reid, Damian J. Murphy, Andrew J. Spargo, Andrew D. Mackinnon

Publications

During the Deep Propagating Gravity Wave Experiment (DEEPWAVE) 13 July 2014 research flight over the South Island of New Zealand, a multiscale spectrum of mountain waves (MWs) was observed. High-resolution measurements of sodium densities were available from ~70 to 100 km for the duration of this flight. A comprehensive technique is presented for obtaining temperature perturbations, T′, from sodium mixing ratios over a range of altitudes, and these T′ were used to calculate the momentum flux (MF) spectra with respect to horizontal wavelengths, λH, for each flight segment. Spectral analysis revealed MWs with spectral power centered at λH of ~80, …

Ultralow Frequency Electrodynamics Of Magnetosphere-Ionosphere Interactions Near The Plasmapause During Substorms, Anatoly V. Streltsov, Evgeny V. Mishin

Publications

Ultra low frequency (ULF) electromagnetic waves have been regularly observed by the CRRES, Cluster, and Van Allen Probes satellites near the plasmapause during substorms. Frequently, the small-scale waves are detected together with a large-scale quasi-stationary electric field collocating with mesoscale plasma flows penetrating into the plasmasphere. These observations suggest that the plasmapause plays an important role in the conversion of the kinetic energy of energetic particles moving toward the Earth from the reconnection site in the magnetotail into a large-scale electric field. The field penetrates along the magnetic field into the ionosphere and generates small-scale, shear Alfvén waves and field-aligned …

On The Short-Term Variability Of Turbulence And Temperature In The Winter Mesosphere, Gerald A. Lehmacher, Miguel F. Larsen, Richard L. Collins, Aroh Barjatya, Boris Strelnikov

Publications

Four mesosphere–lower thermosphere temperature and turbulence profiles were obtained in situ within ∼30 min and over an area of about 100 by 100 km during a sounding rocket experiment conducted on 26 January 2015 at Poker Flat Research Range in Alaska. In this paper we examine the spatial and temporal variability of mesospheric turbulence in relationship to the static stability of the background atmosphere. Using active payload attitude control, neutral density fluctuations, a tracer for turbulence, were observed with very little interference from the payload spin motion, and with high precision (%) at sub-meter resolution. The large-scale vertical temperature structure …

Book Review: Fundamentals Of International Aviation, Alan Bender

International Journal of Aviation, Aeronautics, and Aerospace

Not applicable.

A Diagnostic Metric For Predicting Tropical Cyclone And Mid-Latitude Floods, Jonathon Klepatzki, Shawn M. Milrad

Beyond: Undergraduate Research Journal

This study details a dynamic and thermodynamic metric (i.e., Extreme Flood Index [EFI]) designed to diagnose the frequency and intensity of extreme precipitation events associated with stagnant mid-latitude flow patterns (i.e., Rex blocks). As the global climate warms, rapid Arctic warming may be helping to slow the mid-latitude westerly jet stream, resulting in increased mid-latitude flow stagnation. The combination of long-duration ascent associated with easterly winds and warm moist air increases the severity of extreme precipitation events; as such, the EFI is specifically designed to detect this potent combination of ingredients. In 2013, a Rex block stalled a low-pressure system …

Thermal Removal Of Carbon Dioxide From The Atmosphere: Energy Requirements And Scaling Issues, Ted Von Hippel

Publications

I conduct a systems-level study of direct air capture of CO2 using techniques from thermal physics. This system relies on a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. While technological developments will be required for such a system to operate efficiently, those developments rest on a long history of refrigeration expertise and technology, and they can be developed and tested at modest scale. I estimate that the energy required to remove CO2 via this approach is comparable to direct air capture by other techniques. The …

Error Analysis Of Multi-Needle Langmuir Probe Measurement Technique, Aroh Barjatya, William Merritt

Publications

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.

A Comparison Of Small- And Medium-Scale Gravity Wave Interactions In The Linear And Nonlinear Limits, C. J. Heale, J. B. Snively

Publications

A 2-D numerical model is used to compare interactions between small-scale (SS) (25 km horizontal wavelength, 10 min period) and medium-scale (MS, 250 km horizontal wavelength, 90 min period) gravity waves (GWs) in the Mesosphere and Lower Thermosphere within three different limits. First, the MS wave is specified as a static, horizontally homogeneous ambient atmospheric feature; second, a linear interaction is investigated between excited, time-dependent SS and MS waves, and third, a fully nonlinear interaction at finite amplitudes is considered. It is found that the finite-amplitude wave interactions can cause SS wave breaking aligned with the phase fronts of the …

The General Aviation Pilot Preflight Weather Planning: Weather Products Usability & Limitations, Jayde King, Yolanda Ortiz, Nicholas Defilippis, Thomas A. Guinn, Beth Blickensderfer, Thomas Robert

General Aviation Weather Display Interpretation

Over the last 30 years, a large percentage of weather-related aviation accidents have occurred under General Aviation (GA) operations (FAA, 2010; Fultz & Ashley, 2016; AOPA, 2008).

• Novice Private Pilots VFR into IMC
• High Risk For Incurring Fatality

Aviation Weather Challenges

1. Difficult to interpret Aviation Weather Products
2. Pilot's Decision Making Biases and Errors
3. GA Pilots' Lack of Aviation Weather Experience

Quantitative Examination And Comparison Of Altimetry Rules-Of-Thumb For General Aviation, Thomas A. Guinn

International Journal of Aviation, Aeronautics, and Aerospace

General aviation rules of thumb (ROTs) for density altitude and true altitude are examined and developed. Both ROTs originate from the same basic principle of hydrostatic balance, but differ significantly in the assumptions made regarding the atmospheric temperature profile. While the ROT for DA assumes a standard atmospheric vertical temperature lapse rate, the ROT for true altitude requires information regarding the observed layer-mean temperature of the atmosphere. Since the layer-mean temperature between the aircraft and the surface is typically unknown, it must be inferred from the temperature at a single level by again assuming a linear lapse rate. This method …