Aerosol major ion record at Mount Washington

This study examined the seasonal cycles and regional-scale meteorological controls on the chemical properties of bulk aerosols collected from 1999 to 2004 at Mount Washington, the highest peak in the northeastern United States. The concentrations of NH4+ and SO42− peaked during summer months. The pattern for aerosol NO3− was more complicated with relatively high median concentrations characterizing spring and summer months, but with major elevated events occurring during fall, winter, and spring. The seasonal relationship between NH4+ and SO42− indicated that during warmer months a mixture of (NH4)2SO4 and NH4HSO4 was present, while it was mainly the latter in winter. More acidity and higher concentrations of the major species were generally associated with winds from the southwest and west sectors. The highest (≥95th percentile) concentrations of SO42− and NH4+ were associated with air mass transport from major upwind source regions in the Midwest and along the eastern seaboard. The ionic composition and seasonal cycle observed at Mount Washington were similar to those measured at other northeastern sites, but the range and average concentrations were much lower. These differences were exaggerated during wintertime. Included in this paper are several Eulerian case studies of SO2 conversion to SO42− during transit from Whiteface Mountain, New York, to Mount Washington. The calculations suggest a gas-phase SO2 oxidation rate of ∼1–2% per hour and demonstrate the possibility of using these two sites to investigate the chemical evolution of air masses as they move from Midwestern source regions to northern New England

Ducting conditions for electromagnetic wave propagation in tropical disturbances from GPS dropsonde data

In this thesis, more than 13000 vertical profiles from GPS-enabled dropsondes, recorded from 1996 through 2010, were analyzed to determine the characteristics of electromagnetic and electro-optical ducting in the boundary layer, an environmental condition that significantly affects the propagation of radio waves. A radio wave propagation duct is formed when there are significant gradients in the humidity and temperature profiles of the atmosphere. In this study, the frequency of occurrence and the characteristics (height, depth, and strength) of a duct are identified using the temperature and humidity profiles measured by dropsondes. The identified ducts are separated based on duct types occurring in the lower troposphere: surface ducts, surface-based ducts, and elevated ducts. We further separate the duct occurrence based on the location relative to their respective storms. Based on the number of soundings in different types of tropical disturbances, we chose to further analyze duct conditions in hurricanes and tropical storms. The results suggest frequent occurrence of ducting, especially elevated ducts. This result is consistent with previous research of a similar nature. However, no preference of ducting was identified in any quadrant of the storm.http://archive.org/details/ductingcondition1094539041Lieutenant, United States NavyApproved for public release; distribution is unlimited

Cockpit Text Communications: Evaluating the Efficiency and Accuracy

Non-voice data exchanges will become a primary method of communication between pilots and Air Traffic Controllers as the Federal Aviation Administration’s plan for the Next Generation Air Traffic Control System (NextGen) evolves. In support of this communication evolution, pilots will need the most efficient interface tools in order to accurately and quickly exchange text messages with Air Traffic Control. Keyboards, or similar input devices, will be become a necessity in the cockpit. This study aims to investigate and compare the typing speed and accuracy possible using three sizes of two-hand, QWERTY1 keyboards: a full size (100%), a medium size (92%), and a small size (thumb typing home theater PC keyboard) that could be used for aviation data exchanges. Each study participant was administered 15 typing tests having aviation specific content, on each keyboard, including 5 tests of short length, 5 tests of medium length, and 5 tests of long length. The results of this study suggest that in terms of words per minute typing speed, participants using the medium size keyboard had a slightly faster typing speed than with the large keyboard, while the small keyboard produced a considerably slower typing speed than either the medium or large keyboards. In terms of accuracy, participants using the small keyboard had the highest level of accuracy, followed by the medium keyboard, while the least accurate keyboard tended to be the large keyboard. Overall, findings suggest that the optimal size of two-handed, QWERTY keyboard for use in an aircraft cockpit was the medium keyboard

Cockpit Text Communications: Evaluating the Efficiency and Accuracy of Different Keyboards

Non-voice data exchanges will become a primary method of communication between pilots and Air Traffic Controllers as the Federal Aviation Administration’s plan for the Next Generation Air Traffic Control System (NextGen) evolves. In support of this communication evolution, pilots will need the most efficient interface tools in order to accurately and quickly exchange text messages with Air Traffic Control. Keyboards, or similar input devices, will be become a necessity in the cockpit. This study aims to investigate and compare the typing speed and accuracy possible using three sizes of two-hand, QWERTY1 keyboards: a full size (100%), a medium size (92%), and a small size (thumb typing home theater PC keyboard) that could be used for aviation data exchanges. Each study participant was administered 15 typing tests having aviation specific content, on each keyboard, including 5 tests of short length, 5 tests of medium length, and 5 tests of long length. The results of this study suggest that in terms of words per minute typing speed, participants using the medium size keyboard had a slightly faster typing speed than with the large keyboard, while the small keyboard produced a considerably slower typing speed than either the medium or large keyboards. In terms of accuracy, participants using the small keyboard had the highest level of accuracy, followed by the medium keyboard, while the least accurate keyboard tended to be the large keyboard. Overall, findings suggest that the optimal size of two-handed, QWERTY keyboard for use in an aircraft cockpit was the medium keyboard

Risk evaluation with enhaced covariance matrix

We propose a route for the evaluation of risk based on a transformation of the covariance matrix. The approach uses a `potential' or `objective' function. This allows us to rescale data from different assets (or sources) such that each data set then has similar statistical properties in terms of their probability distributions. The method is tested using historical data from both the New York and Warsaw Stock Exchanges.Comment: see urbanowicz.org.p

Spectral aerosol extinction (SpEx): a new instrument for in situ ambient aerosol extinction measurements across the UV/visible wavelength range

We introduce a new instrument for the measurement of in situ ambient aerosol extinction over the 300– 700 nm wavelength range, the spectral aerosol extinction (SpEx) instrument. This measurement capability is envisioned to complement existing in situ instrumentation, allowing for simultaneous measurement of the evolution of aerosol optical, chemical, and physical characteristics in the ambient environment. In this work, a detailed description of the instrument is provided along with characterization tests performed in the laboratory. Measured spectra of NO2 and polystyrene latex spheres (PSLs) agreed well with theoretical calculations. Good agreement was also found with simultaneous aerosol extinction measurements at 450, 530, and 630 nm using CAPS PMex instruments in a series of 22 tests including nonabsorbing compounds, dusts, soot, and black and brown carbon analogs. SpEx measurements are expected to help identify the presence of ambient brown carbon due to its 300 nm lower wavelength limit compared to measurements limited to longer UV and visible wavelengths. Extinction spectra obtained with SpEx contain more information than can be conveyed by a simple power law fit (typically represented by Ångström exponents). Planned future improvements aim to lower detection limits and ruggedize the instrument for mobile operation