MST radar data-base management

Data management for Mesospheric-Stratospheric-Tropospheric, (MST) radars is addressed. An incoherent-scatter radar data base is discussed in terms of purpose, centralization, scope, and nature of the data base management system

Plasma Lines in the Auroral E Layer

The first successful measurements of plasma lines in the auroral E layer were made in January 1976 using the Chatanika incoherent scatter radar. Although they are considerably weaker than the signal from the ion component, the plasma line signals are readily detectable. Typical signal-to-noise ratios were about 4%. In this series of experiments, plasma lines were observed in the interval between 3.8 and 6.0 MHz, which corresponds to phase energies between 0.55 and 1.4 eV. They were found between 98 and 134 km; the derived plasma wave intensities varied between 0.06 and 1.0 eV, and the enhancements between 4 and 30 times the thermal level. There was a marked altitude dependence: the weakest waves were at the lowest altitudes, and the strongest were just below the maximum altitudes. There was no discernible frequency dependence at the lowest altitudes, but at the highest altitudes the lower-frequency plasma waves were stronger. These variations are probably related to the altitude variations of the suprathermal electron spectrum and of the electron temperature

Predator Defense and Host Selection Behavior of Billbugs (Coleoptera: Dryophthoridae)

Billbugs are a complex of weevils that feed on the roots of turfgrass, causing severe damage to the plants. These pests are traditionally managed with applications of insecticides. However, there is a need for non-chemical management tools. Here I investigate billbug behavior in relation to two potential avenues for more sustainable management: using resident predators to suppress billbugs (Chapter II) and selecting specific turfgrasses that resist billbug damage (Chapter III). In Chapter II, I investigate the effects of predator presence and cues associated with their presence on billbug behavior. Though resident predators contribute very little to billbug suppression through directly killing and consuming billbugs, I found that the presence of predators caused billbugs to spend less time feeding and mating, and more time on predator avoidance behaviors. Moreover, predator odor alone induced similar changes, suggesting that adult billbug detect predators using their odor. Although predators do not often directly consume billbugs, their presence may still contribute to billbug suppression. My findings also provide the framework for further investigation of predator chemicals as a potential billbug management tool. In chapter III, I examine adult billbug preferences for water stressed turfgrasses, and turfgrass cultivars with different drought resistance traits. I found that billbugs were more abundant in drier areas, and that billbug damage was higher in turfgrass with low drought resistance. While billbugs did prefer some turfgrasses over others, they did not prefer drought stressed or drought susceptible plants. Drought resistant turfgrasses are available to alleviate drought stress and may generally suffer less billbug damage, however, this does not appear to be a function of repelling adult billbugs. Continued evaluation of the factors that drive billbug preferences among turfgrasses, and turfgrass of traits associated with lower billbug damage could guide cultivar development against two key stressors, drought and billbugs, in the Intermountain West. Overall, my research shows that short term changes in turfgrass management practices, such as conserving the natural predator community and selecting specific types of turfgrass, could assist in billbug management. In the long term, investigation of billbug management using predator chemicals and development of turfgrasses that resist billbug damage could form the basis of sustainable billbug management programs

Understanding multicollinearity between the solar coefficient and linear trend coefficient in ordinary least squares regression.

When doing regression multicollinearity between model variables can be a problem. This is a problem for time and solar coefficients for data sets of mesospheric temperatures spanning one solar cycle or less. This paper focuses on the problem of multicollinearity between the linear term and the solar term in an ordinary least squares regression (OLSR). The multicollinearity between those two terms will change according to the phase of the solar cycle. If solar maximum occurs in the middle of the second half of the data set there is significant negative correlation between them. Conversely, if solar maximum occurs in the middle of the first half of the data set there is significant positive correlation. The optimal phase of the solar cycle relative to the data is for solar max or solar min to occur in the time center of the data set. In that particular case the correlation between the linear and solar coefficients is minimized. When the data set spans approximately 1.3 solar cycles or greater then multicollinearity between the time coefficient and solar coefficient is not an issue. The degree of multicollinearity is independent of the magnitude of the solar response and cooling rate

Patient expectations of surgery outcomes for appearance-altering eye conditions

Conditions affecting the eyes can be associated with impaired vision, social functioning and reduced quality of life. Unsurprisingly, patients with these problems often seek surgery to improve their vision and change their appearance. Elizabeth Jenkinson and Sadie Wickwar consider research suggesting that patients may have differing expectations of outcomes that can be achieved with surgical interventions

Results from an Extremely Sensitive Rayleigh-Scatter Lidar

Rayleigh-Scatter lidar systems effectively use remote sensing techniques to continuously measure atmospheric regions, such as the mesosphere (45-100km) where in situ measurements are rarely possible. The Rayleigh lidar located at the Atmospheric Lidar Observatory (ALO) on the Utah State campus is currently undergoing upgrades to make it the most sensitive of its kind. Here, the important components of these upgrades and how they will effect the study of a particular atmospheric phenomena, atmospheric gravity waves, will be discussed. We will also summarize what has been done to the system during this year to bring us to the threshold of initial operations

The Effects of Large Data Gaps on Estimating Linear Tred in Autocorrelated Data

It is well known that atmospheric data is autocorrelated. Techniques for fitting a model to autocorrelated data without data gaps are well known. However in cases where large data gaps exist the analysis is more challenging. By large data gaps we mean 16-24% of the possible data present. This paper explores the challenges of estimating the correlation coefficient in an autocorrelated data set containing large data gaps and suggests ways to accurately estimate the autocorrelation and linear trend in a signal when such cases arise

An Earlier Lidar Observation of a Noctilucent Cloud above Logan, Utah (41.7º N, 111.8º W)

A Rayleigh-scatter lidar has been operated at the Atmospheric Lidar Observatory (ALO) on the Utah State University (USU) campus (41.7º N, 111.8º W) for the last 11 years. During the morning of 22 June 1995 a noctilucent cloud (NLC) was observed with the lidar, for approximately one hour, well away from the twilight periods when NLCs are visible. This sighting of an NLC at this latitude shows that the first sighting in 1999 [Wickwar et al., 2002] was not a unique occurrence. This 1995 observation differs from the 1999 one in that temperatures could be deduced. The hourly profiles are at least 20 K cooler than the 11-year June climatology for ALO near the NLC altitude. However, the cool temperatures arose because of a major temperature oscillation or wave, not because the whole profile was cooler. These lidar observations were supplemented by OH rotational observations from approximately 87 km, which also showed unusually cold temperatures on this night. While these NLC observations equatorward of 50° may be significant harbingers of global change, the mechanism is more complicated than a simple overall cooling or increase in water vapor

Plasma Line Measurements at Chatanika with High-Speed Correlator and Filter Bank

In the spring and fall of 1978 we made an extensive series of plasma line and correlative observations with the Chatanika incoherent scatter radar. To make these measurements, we greatly modified the radar receiving system. In addition to enlarging the plasma line filter bank the most significant change was the incorporation of a high-speed correlator provided by the French. This was the first use of a correlator in a monostatic radar to obtain the intensity spectra of naturally occurring plasma lines. In this paper we develop the signal-processing theory that we use to obtain the plasma line intensities from these measurements; we also show that these intensities compare well with those obtained from the filter bank. To show the richness of the phenomena and to explore the capabilities of the correlator, we examine a wide variety of spectra that have been enhanced by secondary electrons in the auroral E layer. From the other simultaneous measurements we are able to relate these spectra and their variations to the auroral situation. We also obtained the first measurements in the auroral region of photoelectron-excited plasma lines in the E and F layers. Perhaps most significant, in the plasma line spectra we detected a Doppler shift that we then used to determine the Birkeland current carried by ambient electrons. Although there is a large estimated uncertainty for this first determination, we obtained a downward Birkeland current of 10 μA/m² in the diffuse aurora in what is, most likely, the equatorward portion of the evening sector auroral oval