The Air Force Global Weather Central operational boundary-layer model

A limited-area seven-layer physical-numerical model for the lower tropospheric region (surface - 1600m) is described. The grid interval, approximately 190km, is half that of the standard numerical weather-prediction grid used in the hemispheric free atmospheric operational model at the Air Force Global Weather Central (AFGWC). This model is an integral part of the complete AFGWC meso-scale (sub-synoptic) numerical analysis and prediction system and is used to provide greater horizontal and vertical resolution in both numerical analyses and forecasts.Important features of this boundary-layer model include: a completely automated objective analysis of input data; the transport of heat and moisture by three-dimensional wind flow; latent heat exchange in water substance phase changes; and eddy fluxes of heat and water vapor.Input data are conventional synoptic surface and upper air reports. Other operational AFGWC prediction models provide input in the form of horizontal wind components at the upper boundary and an estimate of cloudiness above the boundary layer. Forecasts for the lower boundary and surface layer are empirically derived. Despite some approximations which broadly simplify the real planetary boundary-layer processes, operational use for highly weather-sensitive Air Weather Service support indicates that the model is capable of producing accurate detailed forecasts for periods of up to 24h.A modified version of this paper was presented at the IUGG-IAMAP-AMS conference on Planetary Boundary Layers at Boulder, Colo., 18–21 March, 1970, and at the 5th annual Congress of the Canadian Meteorological Society, at Macdonald College, 12–14 May, 1971.     

Magneto-elastic waves and disturbances in initially stressed conducting media: II

Summary The paper is concerned with the investigation of the magneto-elastic waves and disturbances in initially stressed conducting media. Firstly, (a) the steady state response to moving loads in a magneto-elastic initially stressed conducting medium under an uniaxial tension has been discussed. Secondly, (b) the Lamb's problem corresponding to a line load suddenly applied in a magneto-elastic initially stressed conducting half-space bounded by a plane under uniaxial tension has been investigated. The final results obtained in both cases are in agreement with the corresponding classical problems when the initial tension is zero and the magnetic field is absent.     

Electromagnetic propagation in an idealized earth crust waveguide,part I

Summary The electromagnetic mode characteristics for the earthcrust waveguide are considered. The formulation allows for any depth-conductivity profile, but the specific results are only for a homogeneous sub-surface waveguide region with a finitely conducting lower layer and a perfectly conducting upper layer. Attenuation rates of the order of 1 dB/km are possible for operating frequencies of 20 kHz or lower if the crystalline rock in the waveguide has conductivities less than 10^–6 mhos per meter.     

Steady state hodographs in a baroclinic boundary layer

If the steady-state geostrophic wind vector varies exponentially with height in the planetary boundary layer, calculated hodographs of the 24-hour mean wind resemble the classic Ekman spiral distorted by thermal effects. For such an assumed distribution, Lettau's (1967) conclusion that the effects of thermal influence on the steady-state boundary-layer winds can be linearly superimposed on the effects of internal friction is justified.The minimum value of the cross-isobar angle of the surface wind for a given magnitude of the thermal wind vector occurs when that vector points about 345° to the right of the surface geostrophic wind vector and the maximum value occurs when it points at an azimuth of about 120° relative to the surface geostrophic wind vector. The range of values of the cross-isobar angle is almost directly proportional to the magnitude of the thermal wind vector.Hodographs resulting from the assumed variation of the geostrophic wind have approximately the same shape as 24-hour mean hodographs at two locations over the Great Plains.This work is part of a thesis submitted to the University of Wisconsin in partial fulfillment of the requirements for the Ph.D. Degree, written under the supervision of Professor H. Lettau, Department of Meteorology.     

Interpretation of vertical gravity and magnetic profiles

Summary Methods have been developed by quantitatively interpreting gravity and magnetic data in vertical bore-holes or shafts for geological bodies that can be approximated by spheres and cylinders. Master diagrams that can be directly used by the interpreter are provided.     

Th-228/Th-232 and Pb-210 geochronologies in marine and lake sediments

Two dating techniques, applicable to coastal marine and lacustrine sediments over periods ranging from years to a century, evolve from the natural radioactive series: Th-228/ Th-232 from the Th-232 series and Pb-210 from the U-238 series.There is an excess of Th-228 over and above that supported by the parents Th-232 or Ra-228 in such deposits. The amounts of Th-232-supported and Ra-228-supported Th-228 are similar, indicating that both radium and thorium isotopes are removed from solution in these coastal zones quite rapidly after introduction or formation. The radium isotopes are probably transferred from the overlying waters to the sediments via phytoplankton, where they are reportedly enriched. In the surface levels of the deposits analyzed, there is nearly an order of magnitude more unsupported than supported Th-228. This excess Th-228 can be used both for dating purposes over time periods of the order of a decade and as permissive evidence that the uppermost levels of the deposit were obtained during the coring operation. Preliminary results from several lakes indicate the possibility that Th-228/Th-232 geochronologies are held by their sediments.Average rates of accumulation of lake sediments have been obtained from decreases in Pb-210 activity as a function of depth, although surface layers of the deposits may not have been recovered in the coring operation. Finally, Pb-210 geochronologies have been extended from varved to unvarved marine sediments.     

Electricity consumption patterns within cities: application of a data-driven settlement characterization method

ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.     

Observations of the infrared FeXIII lines in the solar corona of 12 November, 1966

The purpose of this paper is to report on some intensity measurements of the Fe xiii lines at 10 747 Å and 10 798 Å made during the total eclipse of 12 November, 1966. Infrared spectra were taken of the solar corona at a dispersion of 90 Å per mm, using an RCA image converter and spectrograph aboard the NASA CV 990 aircraft off the coast of southern Brazil. The spectra have been reduced to equivalent width in terms of the coronal continuum and values derived for different points in the corona.The observed equivalent widths of the lines lie in the range 10 to 30 Å for the 10 747 line and 5 to 12 Å for the 10 798 line. The ratio of these equivalent widths is found to vary from 2.3 in the inner corona to 6 at a point 1.36 solar radii from the center of the Sun.The above results are discussed in terms of the excitation mechanisms involved in producing the lines. In particular, the results are compared with the recent theoretical calculations of Chevalier and Lambert, who are the first to include the effects of proton collisions in the excitation of the 3p ^{2 3} P levels of Fexiii. Our observations are consistent with an electron density of 4 × 10⁸ in the inner corona; a value which compares favorably with those derived by other observers from the strength of the K continuum. These are, to our knowledge, the first eclipse observations of the infrared Fe xiii lines which indicate that proton collisions are important in the excitation of the coronal lines. The coronal abundance of iron is estimated from the equivalent width of the 10 747 line, and in common with other observers we find an overabundance as compared to the photospheric abundance by a factor of 10.     

The magnetic properties of solar surges

High resolution on- and off-band Hα filtergrams of disk solar surges obtained with the Vacuum Tower Telescope of the Sacramento Peak Observatory have been compared to magnetic data.

1. Surges constitute clusters of very fine dark (sometimes bright) filaments where each thread connects to an Ellerman bomb brightening. If the magnetic map reveals the existence of a satellite polarity as defined by Rust (1968), the bomb(s) lies over it.
2. Although a large fraction of surges is not associated with clearly detectable satellite polarities, events are strongly favored in regions of evolving magnetic features, characterized by dimensions of about 10 000 km and significant flux change over a period of less than a day. A flux change rate of 3 × 10¹⁵ Mx s^?1 has been measured along at least three homologous bomb-surge events in a satellite of region MW 18594. Surges appear to be related to rising flux of one polarity into a region of stronger opposite flux.
3. The trajectories of surges are matched by magnetic lines of force computed in the current-free approximation.