An experiment originally done by McElhaney et al. was repeated to obtain additional information about the effects of electrical fields on osteoporosis of disuse. The right femurs of 35 male rats were immobilized in plaster casts. Sixteen rats were treated with transcutaneous electrical fields of 30 Hz and approximately 100 V/cm for periods of 2 or 8 h a day. While the right femurs of the untreated rats were found to be atrophic with respect to the opposite limb, in the treated rats the immobilized femur was made larger than the opposite bone. Longer daily treatments exaggerated this effect. The tumors found in the previous study were not seen in our experiments. Other similarities and differences in the 2 studies are discussed.

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A method has been developed for retrieval of wind velocity profiles from satellite sounder radiances using a neural network technique. Each wind velocity represents a mean value for a layer approximately centred at that standard height or pressure level. The neural network input vector includes sounder radiances from the Geostationary Operational Environmental Satellite (GOES), plus ancillary information such as latitude and longitude. A set of ‘co‐incident’ rawinsonde soundings provide the ‘truth’ data set. In the initial results root mean square errors for the standard levels from 850 to 300 hPa have about the same magnitude as those for current methods such as tracking of moisture features in GOES imagery. As with more traditional methods, the largest root mean square error occurs near the tropopause. Although the results to date appear highly promising, considerable further work is needed before we have an operationally capable technique. Copyright © 2000 Royal Meteorological Society

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A method is presented to obtain normalized high resolution slant path transmittance spectra of the atmosphere. Sample spectra are presented. The spectra are of use in remote sensing applications for various types of atmospheric physics and atmospheric photochemistry research, for validating line parameter compilations, and for modeling slant path radiative transfer. The sample spectra are used to demonstrate improved accuracy of line-by-line transmission models when recently reported water vapor line parameters are substituted for those in the 1986 AFGL line parameter compilation in the region near 1 microm.

Atmospheric propagation tests in support of electro optics system development frequently require measurement of the atmospheric transmission at discrete frequencies or the average transmission for a finite spectral bandwidth. The conditions of the test may require that measurements be made over horizontal or slant paths, or even that a moving source be tracked. In many tests it is also necessary to acquire slant path atmospheric turbulence data. A measure of the transverse coherence length (ro), isoplanatic angle (θo), and/or turbulence structure constant (Cn2) profile, may be required. In order to address these needs, an extremely versatile Mobile Atmospheric Profiling System (MAPS) has been designed and fabricated. Field tests have been under way for several months and a variety of data has been collected.

High resolution atmospheric transmission spectra collected with a Fourier transform instrument sometimes exhibit small systematic shifts in the apparent positions of spectral features. Although small, these shifts result in line shape distortions such as "S-curving" when, in the data reduction, one spectrum must be divided by another. The origin of the shifting is in small residual angular deviations between the laser reference and measurement beams and the mechanical axis of the spectrometer. Thermal distortion of the instrument resulting from temperature gradients that change from spectrum to spectrum during a data acquisition operation are the source of the angular deviation. The authors typically measure spectra under field conditions by using trailer-mounted instruments. The level of temperature control necessary to eliminate shifting is not possible under these conditions. Strategies must be found to reduce or eliminate the effects during processing. The processing method that is explored here is to measure the relative shift between the individual spectra and then to interpolate one of them to the precise spatial frequency values present in the other prior to point-by-point division. Relatively simple interpolation schemes yield significant reduction of the distortion when applied to simulated data, and smaller but still good reduction when applied to measured spectra.