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Method for processing Nb3Sn and other intermetallic compound superconductors produces a twisted, stabilized wire or tube which can be used to wind electromagnetics, armatures, rotors, and field windings for motors and generators as well as other magnetic devices.
An account is given of the results of recent studies of the effect of a spatially sheared wind field on airplane aerodynamics; the wind shear was computed by a modified vortex-lattice computer program, and characterized through the formulation of wind shear aerodynamic coefficients. The magnitude of the aerodynamic effect was demonstrated by computing the change in conventional wing/tail configuration aerodynamics for a fixed flight path through a simulated microburst. A substantial portion of the control authority of the aircraft may be required to counteract the wind shear-induced forces and moments in the microburst environment; both aperiodic and oscillatory instabilities may be generated by shear-dependent dynamic modes.
As part of its program to develop coherent heterodyne detection lidar technology for space, airborne, and ground based applications, the Optical Environment Division of the USAF's Phillips Laboratory developed a compact coherent CO2 TEA lidar system. Although originally conceived as a high altitude balloon borne system, the lidar is presently integrated into a trailer for ground based field measurements of aerosols and wind fields. In this role, it will also serve as a testbed for signal acquisition and processing development for planned future airborne and space based solid state lidar systems. The system has also found significance in new areas of interest to the Air Force such as cloud studies and coherent Differential Absorption Lidar (DIAL) systems.
Doppler line profile measurements of the OI lambda 557.7 nm 'green line' emission, made by the Fabry-Perot interferometer on Dynamics Explorer 2, have provided altitude profiles of the meridional component of the lower thermospheric neutral wind. The wind inversion technique of Nardi has been used to extract the neutral wind profiles from the line-of-sight measurements. Individual lambda 557.7 nm Doppler line profiles and inverted volume-emission-rate and neutral-wind profiles are presented. Neutral wind measurements from the about 120 km altitude level, obtained on multiple orbital passes over the summer hemisphere polar region, have been merged to produce a synthesized averaged 'vector' wind field in geomagnetic coordinates. The wind pattern exhibits a region of anticyclonic vorticity in the daytime sector of the magnetic polar cap. Averaged winds of about 300 m/sec in the equatorial direction are observed in the early morning sector. The satellite winds are in reasonable agreement with the predictions of the NCAR and UCL thermosphere general circulation models, with significant regional discrepancies evident in both magnitude and direction.
A summary of the results of a detailed study of the vertical structure of mesoscale gravity waves conducted during the Cooperative Convective Precipitation Experiment (CCOPE) is presented. Pressure perturbation fields derived from the Doppler wind fields are compared with the vertical structure of eigenfunctions resulting from a solution to the Taylor-Goldstein linear wave equation for an atmosphere whose mean state is described by vertical profiles obtained from a representative CCOPE sounding. An analysis of the potential for shear instability is also performed on all of the soundings taken on this day to assess the representativeness of the one chosen for the linear theoretical analysis.
Effect of a weak interplanetary magnetic field on solar wind-geomagnetic field interaction
The possible production of electric fields parallel to the magnetic field by dynamo winds in the E region is examined, using a jet stream wind model. Current return paths through the F region above the stream are examined as well as return paths through the conjugate ionosphere. The Wulf geometry with horizontal winds moving in opposite directions one above the other is also examined. Parallel electric fields are found to depend strongly on the width of current sheets at the edges of the jet stream. If these are narrow enough, appreciable parallel electric fields are produced.
Convective cold pools are important modulators of the onset and evolution of deep convection in the tropics. This work leverages a dataset derived from the Advanced Scatterometer (ASCAT) satellite instrument by Garg et al. (2020) to quantify seasonal variations in cold pool activity and their relationship to deep convection across tropical ocean basins. The dataset identifies gradient features (GFs) in the surface wind field, which have been shown to serve as reliable proxies for the boundaries of atmospheric cold pools. We examine the relationship between GFs and climatologies of precipitation, column relative humidity (CRH), and bulk vertical wind shear. We also collocate GFs with precipitation and CRH. High GF frequency, precipitation, and CRH coincide in many regions of the tropics, consistent with our understanding of the physical connections between precipitation and cold pool generation. On the other hand, climatological bulk wind shear is often low in convective regions, and there is a weak inverse correlation between GF frequency and bulk wind shear, while our prior expectation might have been that shear promotes cold pool formation. Compared to GF frequency, GF size shows a weaker relationship with the convective environment, with some of the largest GF sizes occurring at lower CRH values for a given rainfall rate. In a few exceptional regions and seasons, such as the Indian Ocean in northern hemisphere summer, the region of greatest precipitation does not coincide with the region of greatest GF frequency. These cases also have very high seasonal mean CRH, suggesting that in these regions cold pool formation is suppressed by reduced evaporation of precipitation.
Atmospheric variability over time scales greater than one month is conceptually simplified and readily recognized from vertical cross-sections of zonal-monthly mean data. The reduction to two dimensions, latitude and height, explicitly eliminates all zonal waves but implicity retains their effects on the thermal-pressure fields and the dynamically related zonal wind fields. This atlas contains 96 examples, spanning all latitudes in both the northern and southern hemispheres and two decades in pressure, from 1000 to 10 mb. Four analyses, representing each month from January 1973 through December 1980, depicts the potential virtual temperature, the observed zonal wind velocity, the virtual temperature and the geostrophic zonal wind velocity. Each variable is contoured at a close interval to facilitate visual estimates of stability and vorticity via their gradients. The analyses are generated and contoured by objective computer methods from just one data source: in situ measurements from the conventional rawin-radiosonde system. Although the analyses are independently made at constant pressure levels (the mandatory levels) the cross-sections are drawn with geopotential height as the ordinate. With this ordinate one can observe the seasonal expansion and contraction of the earth's atmosphere, especially that of the polar stratosphere. Also, the quasi-biannual cycle can be identified and studied directly from successive cross-sections.
During the NOAA/NESDIS 2005 Hurricane Season (HS2005) and the 2006 Winter Experiment, the University of Massachusetts (UMass) installed two instruments on the NOAA N42RF WP-3D research aircraft: the Imaging Wind and Rain Airborne Profiler (IWRAP) and the Simultaneous Frequency Microwave Radiometer (SFMR). IWRAP is a dual-band (C- and Ku), dual-polarized pencil-beam airborne radar that profiles the volume backscatter and Doppler velocity from rain and that also measures the ocean backscatter response. It simultaneously profiles along four separate incidence angles while conically scanning at 60 RPM. SFMR is a C-band nadir viewing radiometer that measures the emission from the ocean surface and intervening atmosphere simultaneously at six frequencies. It is designed to obtain the surface wind speed and the column average rain rate. Both instruments have previously been flown during the 2002, 2003 and 2004 hurricane seasons. For the HS2005, the IWRAP system was modified to implement a raw data acquisition system. The importance of the raw data system arises when trying to profile the atmosphere all the way down to the surface with a non-nadir looking radar system. With this particular geometry, problems arise mainly from the fact that both rain and ocean provide a return echo coincident in time through the antenna s main lobe. This paper shows how this limitation has been removed and presents initial results demonstrating its new capabilities to derive the atmospheric boundary layer (ABL) wind field within the inner core of hurricanes to much lower altitudes than the ones the original system was capable of, and to analyze the spectral response of the ocean backscatter and the rain under different wind and rain conditions.
In this study, satellite observations, in situ measurements, and model simulations are combined to assess the oceanic response to surface wind forcing in the equatorial Pacific. The surface wind fields derived from observations by the spaceborne special sensor microwave imager (SSM/I) and from the operational products of the European Centre for Medium-Range Weather Forecasts (ECMWF) are compared. When SSM/I winds are used to force a primitive-equation ocean general circulation model (OGCM), they produce 3 C more surface cooling than ECMWF winds for the eastern equatorial Pacific during the cool phase of an El Nino-Southern Oscillation event. The stronger cooling by SSM/I winds is in good agreement with measurements at the moored buoys and observations by the advanced very high resolution radiometer, indicating that SSM/I winds are superior to ECMWF winds in forcing the tropical ocean. In comparison with measurements from buoys, tide gauges, and the Geosat altimeter, the OGCM simulates the temporal variations of temperature, steric, and sea level changes with reasonable realism when forced with the satellite winds. There are discrepancies between model simulations and observations that are common to both wind forcing fields, one of which is the simulation of zonal currents; they could be attributed to model deficiencies. By examining model simulations under two winds, vertical heat advection and uplifting of the thermocline are found to be the dominant factors in the anomalous cooling of the ocean mixed layer.
Low-level jets (LLJs) over the Great Plains are well-known for their importance in transporting moisture from the Gulf of Mexico and forming precipitation in the Central US. However, the impact of irrigation practice on LLJs is rarely studied. To understand the irrigation impact on the Great Plains LLJs, the Weather Research and Forecasting (WRF) model is employed with and without an irrigation scheme. The simulated wind field is evaluated against the observed wind from Midlatitude Continental Convective Clouds Experiment (MC3E). The results show that adding irrigation improves the simulated wind, especially at lower altitudes below 800 hPa. Irrigation reduces the LLJ frequency over the Great Plains, mainly by reducing the intense LLJ frequency. The reduced LLJ frequency is caused by the irrigation-induced weakening of meridional wind. The favorable conditions for LLJs have been identified by examining the mechanism associated with LLJs: a ridge-like pattern with weak and calm synoptic-scale conditions in the mid-levels and a strong west-east temperature gradient at lower levels that promote meridional winds. Irrigation-induced cooling leads to a baroclinic pattern with high pressure at lower altitudes over the irrigation region and low pressure in the mid- and upper levels in the downstream region, resulting in a northerly component that hinders the formation of LLJs. Low-level surface cooling also decreases the west-east temperature gradient and hence weakens the thermal wind forcing. The irrigation-induced mid-level low and weaker west-east temperature gradient are responsible for the reduced meridional winds and the reduced LLJ frequencies.
Solar wind speed relation with magnetospheric convective electric field on dusk meridian
Results on large-scale periodic variations of the stratospheric-mesospheric temperature field based on Meteorological Rocket Network (MRN) measurements are reported for a long-term (12-year) mean, the quasi-biennial oscillation (QBO), and the first three harmonics of the annual wave (annual wave, semi-annual wave, and terannual wave or 4-month variation). Station-to-station comparisons are tabulated and charted for amplitude and phase of periodic variations in the temperature field. Masking and biasing factors, such as diurnal tides, solar radiation variations, mean monthly variations, instrument lag, aerodynamic heating, are singled out for attention. Models of the stratosphere will have to account for these oscillations of different periods in the thermal field and related properties of the wind fields, with multilayered horizontal stratification with height taken into account.-
This paper reviews the major theories which have been proposed to explain the remanent magnetism found in the lunar crust. A total of nine different mechanisms for lunar magnetism are discussed and evaluated in light of the theoretical and experimental constraints pertinent to lunar magnetism. It is concluded that none of these theories in their present state of development satisfy all the known constraints. However, the theories which agree best with the present understanding of the moon are meteorite impact magnetization, thermoelectric dynamo field generation, and an early solar wind field.
A concept is presented which can permit turbulence simulation in the vicinity of microbursts. The method involves a large data base, but should be fast enough for use with flight simulators. The model permits any pilot to simulate any flight maneuver in any aircraft. The model simulates a wind field with three-component mean winds and three-component turbulent gusts, and gust variation over the body of an aircraft so that all aerodynamic loads and moments can be calculated. The time and space variation of mean winds and turbulent intensities associated with a particular atmospheric phenomenon such as a microburst is used in the model. In fact, Doppler radar data such as provided by JAWS is uniquely suited for use with the proposed model. The concept is completely general and is not restricted to microburst studies. Reentry and flight in terrestrial or planetary atmospheres could be realistically simulated if supporting data of sufficient resolution were available.
The FGGE/winter-Monex wind data from 850 and 200 mb are used to analyze the short-term teleconnections over the tropical and midlatitude Pacific and monsoonal surges in the winter of 1978-79. The data were taken twice a day, and included the total wind field, the computed rotational and divergent winds, the velocity potential, and the streamfunction. Cold surges were identified from shipboard data over the South China Sea and characterized an increase in the surface northerly wind and a surface pressure differential between Hong Kong and 30 deg N, 115 deg E. Midlatitude baroclinic disturbances triggered the cold surges, which displayed intensities dependent on the strength of the midlatitude anticyclogenesis and the intensity of the East Asia local Hadley cell. Fluctuations in the 200 mb jet streak over Japan indicated changes in eddy behavior over the North Pacific and the intensity of the East Asia local Hadley cell circulation and tropical convection. It was concluded that midlatitude synoptic systems could force equatorial convection that produces remote midlatitude responses.
A method for generating high-resolution wind maps from scatterometer data was developed and tested on synthetic data for the northeast Pacific Ocean. It is shown that, unlike the wind fields generated by current GCMs, the wind maps constructed by this method retain the high spatial resolution of the scatterometer wherever adequate measurements exist. For the NASA scatterometer, this method would produce every 12 hours a wind map with spatial resolution that preserves the small-scale features of the original data over about half the mapped region. Over the rest of the region, maps with somewhat lower resolution and accuracy will be obtained.