Full versus limited versus no steerability

The range of phenomena of the MST radar technique to divide the steerability versus nonsteerability problem into two broad with a third subset that lies between these two limits are studied. Processes that vary on a horizontal scale which are comparable to the area of the probing radar beam can best be fully steerable beams. The use of fixed beam systems would be a long term study of the mean wind field. Orographic effects due to mountain ridges and/or land-sea interfaces demand steerable beams, particularly if the effects are three dimensional in character. In view of their lack of moving parts fixed beam systems are more reliable. It is assumed that the reliability of a system is inversely proportioned to the number of moving parts. This is not a problem for fixed beam systems

Climatology of gravity waves over Poker Flat, Alaska for 1983

An analysis of short-period wind fluctuations over Poker Flat, Alaska, obtained using the Poker Flat mesosphere-stratosphere-troposphere radar is presented. Results are shown for the troposphere and lower stratosphere as well as for the upper mesosphere and lower thermosphere. Contours depict various levels of wind variance (m2s-2). These results pertain only to wind fluctuation periods lying between one and six hours. These particular fluctuations are generally considered to arise primarily from atmospheric gravity waves. Insofar as this is true, the figure thus describes a general climatology of gravity waves at high latitudes

Summary of progress at the Poker Flat Observatory in Alaska

A description of the status of the Poker Flat MST Radar as of early 1983 is included in the 1983 mesosphere-stratosphere-troposphere MST Workshop Proceedings. The Observatory continues to operate in a continuous data-taking mode, except for a three-week planned campaign experiment concurrent with the STATE rocket program during June 1983. Construction of the digital preprocessing system mentioned in the last status report is all but complete. This additional improvement should be operational by late summer. The possibility of steering the array also mentioned in the last status report is being investigated. A project is underway to electronically steer the one-quarter vertical section of the array. Steering will be in finite steps within about + or - 5 deg of vertical. Successful testing of this modification may lead to eventually steering the entire array in this manner. Data analysis of the data base (now more than four years in length) continues with well over one dozen extramural scientific groups participating

Design considerations for high-power VHF radar transceivers: Distributed versus single large transmitter

The factors which enter into the choice of using a single large transmitter versus a number of smaller units in clear-air radar systems are examined. Feedline economics, ease of repair and spare part costs, operating strategy, vulnerability to catastrophic failure, and phase control requirements are considered

Data base management: MSTRAC (keynote paper), part 8

Technical Aspects of MST radars were discussed. The name of the group is MST Radar Coordination (MSTRAC). The geophysical parameters to be included in the sample data tapes were determined. It was suggested that MSTRAC compile a catalog of existing data at each of the facilities. It is found that: (1) there is a community of interested users for MST data; (2) the initial responses from observatories indicates that interest in MSTRAC is not overwhelming, probably because of time involved; and (3) the program needs reassessment

The NOAA TOGA antenna array

The Aeronomy Laboratory recently installed a 100 x 100 meter array antenna with limited beam steering on Christmas Island as a part of the TOGA (Tropical Ocean and Global Atmosphere) program. The array and the associated beam steering and indicating hardware are described

“An Impediment to Those Who Would Walk the Difficult Way”: How St. Francis of Assisi’s Revolution in Catholic Thought Was Built on the Perceived Inferiority of Femininity

St. Francis of Assisi is undoubtedly one of the most famous saints in the Catholic Church. Known for his complete poverty and deep love for the poor and animals, the Little Poor Man of Assisi has become renowned for his way of life and the fraternity he started that has continued for over eight hundred years. In an organization rife with cardinal sin, Francis was in stark contrast with his asceticism and rankless order. However, St. Francis’ entire ideology is built on the Catholic belief that women are inherently inferior to men and dangerous to those following God. Francis used feminine descriptors to denote his inferiority to God and saw relationships with women—platonic and romantic—as the gravest of sins. Despite facing immense challenges in pursuing the saint’s faith, women have been some of the most devout and important Franciscans. St. Francis is deserving of recognition for his humility, care for those who could not care for themselves, and the movement he inspired within the Church; however, the hateful beliefs that drove the saint to his good deeds in the first place must be central in any Franciscan study

Archival of Poker Flat MST radar data

The Poker Flat MST (mesosphere stratosphere troposphere) radar has operated from early 1979 to 1985. The data recorded during that time resides on some 1100 magnetic tapes. A second set containing only the derived parameters of velocity, width and signal to noise of the primary echo at each height, plus the noise spectra, occupies another 250 tapes. While processing to generate the compressed data set does correct some known errors, no attempt has been made to identify or remove spurious echoes. Because the Poker Flat data set is such a unique and valuable resource, a proposal is made to archive the data in forms more useful for analysis. The archived data set would contain only the parameters for significant echoes with contamination from airplanes, unwanted ionospheric returns, frequently aliased Doppler signals and other sources removed. The archived set should be as good or better than the example shown and may occupy only 25 to 50 tapes

Capabilities and limitations of existing MST radars: Poker Flat

Designed as a prototype system to continuously monitor the atmosphere up to approximately 100 km, the Poker Flat MST radar began operating in 1979 at a relatively low sensitivity. In almost continuous operation since then, the system is steadily increasing in sensitivity to its ultimate design characteristics. Current and final parameters are listed. The advantages of its modular design, which uses 64 transmitting modules distributed through the 200 mx 200 m antenna array include: easy maintenance, beam switching using very low power switching, air cooled transmitting tubes, lower feedline costs, and no moving parts. Continuous, uninterrupted operation ( 4 years) and less man-made interference because of the remote location) are other assets. Most disadvantages are related to its not-yet-finished status, climate, moose excursions, and operating expenses

Current status of the Poker Flat MST radar

The change of the Poker Flat, Alaska, Mesosphere-Stratosphere (MST) radar to a configuration to measure gravity-wave momentum flux is discussed