Hurricane Kinetic Energy Spectra from In Situ Aircraft Observations

Since the pioneering paper by Nastrom and Gage on aircraft-derived power spectra, significant progress has been made in understanding the wavenumber distribution of energy in Earth’s atmosphere and its implications for the intrinsic limits of weather forecasting. Improvements in tropical cyclone intensity predictions have lagged those of global weather forecasting, and limited intrinsic predictability may be partially responsible. In this study, we construct power spectra from aircraft data of over 1200 missions carried out by the National Oceanic and Atmospheric Administration (NOAA) and Air Force Reserve Command (AFRC) Hurricane Hunters. Each mission is parsed into distinct flight legs, and legs meeting a specified set of criteria are used for spectral analysis. Here, we produce power spectra composites for each category of the Saffir–Simpson scale, revealing a systematic relationship between spectral slope and storm intensity. Specifically, as storm intensity increases, we find that 1) spectral slope becomes steeper across scales from 10 to 160 km and 2) the transition zone where spectral slope begins to steepen shifts downscale.

The Use of Voice and Head-Tracking for Hands-Free Human-Computer Interaction

This Practitioner Paper discusses the second in a series of studies examining the Voice Head Integrated Control (VHIC) suite, which combines use of voice commands and a head-tracking device as an alternative to the mouse and keyboard. This VHIC system is currently being investigated as a hands-free interface for accessing digitized aircraft technical manuals. The present study was conducted to validate the voice command vocabulary and provide an initial evaluation of the VHIC hardware. Aircraft maintainers from the 445th C-141 Air Force Reserve Unit served as subjects. The current study made use of the fully functioning VHIC system, complete with head-tracking and voice recognition capabilities. User strategies followed on-screen interface characteristics and the user's experience level with computers. Several error categories were tracked and subjective feedback was collected. A series of recommendations are presented which address the strategic application of the VHIC system in an aircraft maintenance environment.