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  • METEOROLOGY AND CLIMATOLOGY  (354)
  • FLUID MECHANICS AND HEAT TRANSFER  (331)
  • 1990-1994
  • 1980-1984  (680)
  • 1955-1959  (5)
  • 1935-1939
  • 1925-1929
  • 1983  (680)
  • 1957  (5)
  • 1938
  • 1929
Collection
Keywords
Years
  • 1990-1994
  • 1980-1984  (680)
  • 1955-1959  (5)
  • 1935-1939
  • 1925-1929
Year
  • 1
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    Joint Airport Weather Studies (AWS) project (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The joint airport weather studies (JAWS) project is discussed. The major objectives of the JAWS Project are a fundamental description of the phenomenon, a determination of the hazard potential and a definition of a protection and warning system, all of which are relative to low level wind shear. Aspects of the low level wind shear phenomenon. The principal focus, however, is the microburst. The microburst is fundamentally a rather simple atmospheric flow. It is a downdraft that, upon approaching the surface, spreads out horizontally, producing a diverging radial flow in all directions. For any direction that an aircraft flies through the microburst, it will first encounter increasing head winds; then the remnants of the downdraft; and then, increasing tail wind.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 85-95
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  • 2
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    Lightning strike experience in the NASA F-106B storm hazards program (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A heavily instrumented F-106B aircraft was flown in thunderstorms to gather data for characterizing lightning at aircraft operating altitudes. Conventional weather finding techniques are supplemented with UHF lightning mapping radar to select the most active storm cells and the most likely altitude for obtaining direct lightning strikes to the airplane. One hundred seventy-six strikes were obtained in a 3 year period, mostly at an altitude of above 25,000 feet.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 63-65
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  • 3
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    Wind shear and vortex wake research in UK, 1982 (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A wind shear and vortex wake and their impact on aircraft were investigated. The systems and advice to help pilots, and rational scientific methods to assist in advising certification authorities and those interested in improving flight safety were developed. Wind Shear and Vortex Wakes are related, they are both invisible enemies of aircraft in the form of large disturbances in the atmosphere, both cause major accidents. Problems of building wakes at airports are is considered. Research on wind shear was initiated by the American FAA following the Boston, New York and Denver accidents to civil airliners. This resulted in: useful advice to pilots about wind shear; better attempts by the meteorologists at forecasting wind shear conditions; and useful ideas for wind shear measurement and warning systems. Three major research tasks are outstanding: (1) Worldwide measurements to give reliable estimates of probability and details of the forms of large wind shears; (2) Developments of real time wind shear measuring systems for ground or airborne use; and (3) Establishing relationships between measured wind shear and the potential hazard to an aircraft, or class of aircraft.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 66-83
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  • 4
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    Marked surface inversions and wind shear: A safety risk for departing aircraft (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Marked surface inversions occur most frequently in dry continental climates, where low atmospheric humidity allows heat transfer by long wave thermal radiation. In the northern latitudes, surface inversions reach their maximum intensity during the winter, when the incoming Sun's radiation is negligible and radiative cooling is dominant during the long nights. During winter, air mass boundaries are sharp, which causes formation of marked surface inversions. The existence of these inversions and sharp boundaries increase the risk of wind shear. The information should refer to marked inversions exceeding a temperature difference of 10 deg C up to 1000 feet. The need to determine the temperature range over which he information is operationally needed and the magnitude of the inversion required before a notification to pilots prior to departure is warranted are outlined.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 61-62
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  • 5
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    A cursory glance at results from NASA's B-57B gust gradient program (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Gust Gradient Program is a data intensive effort involving tripple Doppler radar, a surface weather station mesonet and other aircraft. The Joint Airport Weather Studies was utilized to gain additional data. The data were used to fill in the gap in turbulence modeling.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 38-42
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  • 6
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    GEM: Statistical weather forecasting procedure (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The objective of the Generalized Exponential Markov (GEM) Program was to develop a weather forecast guidance system that would: predict between 0 to 6 hours all elements in the airways observations; respond instantly to the latest observed conditions of the surface weather; process these observations at local sites on minicomputing equipment; exceed the accuracy of current persistence predictions at the shortest prediction of one hour and beyond; exceed the accuracy of current forecast model output statistics inside eight hours; and be capable of making predictions at one location for all locations where weather information is available.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 42-44
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  • 7
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    Department of Defense meteorological and environmental inputs to aviation systems (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Recommendations based on need, cost, and achievement of flight safety are offered, and the re-evaluation of weather parameters needed for safe landing operations that lead to reliable and consistent automated observation capabilities are considered.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 19-20
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  • 8
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    Aviation weather services (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The primary responsibilities of the National Weather Service (NWS) are to: provide warnings of severe weather and flooding for the protection of life and property; provide public forecasts for land and adjacent ocean areas for planning and operation; and provide weather support for: production of food and fiber; management of water resources; production, distribution and use of energy; and efficient and safe air operations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 14-16
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  • 9
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    Federal Aviation Administration weather program to improve aviation safety (1983)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The implementation of the National Airspace System (NAS) will improve safety services to aviation. These services include collision avoidance, improved landing systems and better weather data acquisition and dissemination. The program to improve the quality of weather information includes the following: Radar Remote Weather Display System; Flight Service Automation System; Automatic Weather Observation System; Center Weather Processor, and Next Generation Weather Radar Development.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Marshall Space Flight Center Proc.: 6th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 21-25
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  • 10
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    Solution adaptive grid generation (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 651-68
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  • 11
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    Navier-Stokes solution for quasi-three dimensional flow (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 329-33
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  • 12
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    Vectorized, implicit Navier-Stokes solver for 2-D incompressible flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 273-31
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  • 13
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    Clebsch velocity decomposition for rotational conical flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 183-19
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  • 14
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    Influence of convection on the growth of crystals from solution (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: This is a review of the influence of convection on the growth of crystals from solution. The growth rate is increased by convection up to the point where interface kinetics becomes rate controlling. Compositional inhomogeneity and morphological instability (inclusion formation) are probably worse for gentle convection than for either no convection or for vigorous stirring. Stirring, particularly of crystal suspensions, can cause an orders of magnitude increase in the rate of formation of new crystals. This is called 'secondary nucleation'.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Crystal Growth (ISSN 0022-0248); 65; 133-142
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  • 15
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    A case study of the sensitivity of forecast skill to data and data analysis techniques (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A series of experiments have been conducted to examine the sensitivity of forecast skill to various data and data analysis techniques for the 0000 GMT case of January 21, 1979. These include the individual components of the FGGE observing system, the temperatures obtained with different satellite retrieval methods, and the method of vertical interpolation between the mandatory pressure analysis levels and the model sigma levels. It is found that NESS TIROS-N infrared retrievals seriously degrade a rawinsonde-only analysis over land, resulting in a poorer forecast over North America. Less degradation in the 72-hr forecast skill at sea level and some improvement at 500 mb is noted, relative to the control with TIROS-N retrievals produced with a physical inversion method which utilizes a 6-hr forecast first guess. NESS VTPR oceanic retrievals lead to an improved forecast over North America when added to the control.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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  • 16
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    Effect of high latitude filtering on NWP skill (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An assessment is made of the extent to which polar filtering may seriously affect the skill of latitude-longitude NWP models, such as the U.S. Navy's NOGAPS, or the GLAS fourth-order model. The limited experiments which have been completed to date with the 4 x 5-deg, 9-level version of the latter model indicate that the high latitude filter currently in operation affects its forecasting skill very little, with only one exception in which the use of the PG filter significantly improved forecasting.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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  • 17
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    The production of turbulent stress in a shear flow by irrotational fluctuations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Attention is given to the way in which external turbulence affects an initially turbulence-free region in which there is a mean velocity gradient. External turbulence induces irrotational fluctuations in the sheared region which interact with the shear to produce rotational velocity fluctuations and mean Reynolds stresses. Since the actual front between the initial external turbulence and the shear flow is a randomly contorted surface, the turbulence near the front is intermittent, and is presently included in the form of a simple statistical model. In wind tunnel tests, turbulent shear stress was found to grow from zero to significant values in the interaction region. Observed stress magnitude and extent agrees with predictions, and it is concluded that turbulent stresses can be produced by irrotational fluctuations in a region of mean shear.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 137; 307-329
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  • 18
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    Thunderstorm cloud top observations using satellite stereoscopy (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The present investigation has as objective to take a detailed look at the intense squall line over Oklahoma on May 2-3, 1979, using GOES stereoscopy combined with GOES infrared data. The synoptic situation and data sources are considered along with the stereoscopically observed cloud top ascent rates. Cloud top observations of intense thunderstorms are discussed, taking into account a contouring technique, the interpretation of infrared cloud top temperature patterns, and small-scale structure and its variability. It is found that GOES IR cloud top temperatures grossly underestimate the actual cloud top height observed stereoscopically, especially for immature storms. It is difficult to define growing storms below about 10 km in the GOES infrared data.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1949-196
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  • 19
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    Viscous thermocapillary convection at high Marangoni number (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A liquid, contained in a quarter plane, undergoes steady motion due to thermocapillary forcing on its upper boundary, a free surface separating the liquid from a passive gas. The rigid vertical sidewall has a strip whose temperature is elevated compared with the liquid at infinity. A boudnary-layer analysis is performed that is valid for large Marangoni numbers M and Prandtl numbers P. It is found that the Nusselt number N for the horizontal heat transport satisfies N proportional to min (M to the 1 2/7/power, M to the 1 1/5/power, M to the 1 1/10/power) Generalizations are discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 135; 175-188
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  • 20
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    Transport and the seasonal variation of ozone (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The transport mechanisms responsible for the seasonal behavior of total ozone are deduced from the comparison of model results to stratospheric data. The seasonal transport is dominated by a combination of the diabatic circulation and transient planetary wave activity acting on a diffusively and photochemically determined background state. The seasonal variation is not correctly modeled as a diffusive process. The buildup of total ozone at high latitudes during winter is dependent upon transient planetary wave activity of sufficient strength to cause the breakdown of the polar vortex. While midwinter warmings are responsible for enhanced ozone transport to high latitudes, the final warming marking the transition from zonal mean westerlies to zonal mean easterlies is the most important event leading to the spring maximum. The final warming is not followed by reacceleration of the mean flow; so that the ozone transport associated with this event is more pronounced than that associated with midwinter warmings.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Pure and Applied Geophysics (ISSN 0033-4553); 121; 5-6,
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  • 21
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    Conservation laws of wave action and potential enstrophy for Rossby waves in a stratified atmosphere (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The evolution of wave energy, enstrophy, and wave motion for atmospheric Rossby waves in a variable mean flow are discussed from a theoretical and pedagogic standpoint. In the absence of mean flow gradients, the wave energy density satisfies a local conservation law, with the appropriate flow velocity being the group velocity. In the presence of mean flow variations, wave energy is not conserved, but wave action is, provided the mean flow is independent of longitude. Wave enstrophy is conserved for arbitrary variations of the mean flow. Connections with Eiiassen-Palm flux are also discussed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Pure and Applied Geophysics (ISSN 0033-4553); 121; 5-6,; 917-946
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  • 22
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    A parameterization of the absorption in the 15 micron CO2 spectral region with application to climate sensitivity studies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A technique for quantifying the absorption that takes place in the 15 micron CO2 band in the atmosphere is developed as a function of the scaled CO2 content. A spectrally averaged transmission function is defined and a scaling approximation for the absorption coefficient is calculated, as is the width of the absorption band. An assessment is made of the accuracies of the parameterized atmospheric transmittance and cooling rate. The resulting radiation parameterization is applied in a climate sensitivity study. The model is concluded useful in examining atmospheres with a variable CO2 content, with the highest accuracies being available in the troposphere and the lower stratosphere. CO2 doubling the earth's atmosphere is projected to cause a 20 percent warming in the surface temperatures and a 30 percent warming for the tripling of the CO2 content, provided the spectral range for CO2 absorption is extended from 580-760 to 540-800/cm.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; 2183-219
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  • 23
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    The southern oscillation and long-range forecasting of the summer monsoon rainfall over India (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Indian summer monsoon rainfall and the Darwin pressure anomalies are examined for the 81-year period 1901-81. It is found that the tendency of the Darwin pressure anomaly before the monsoon season is a good indicator of the monsoon rainfall anomaly. During the 81-year period, there were only two instances (1901, 1941) when a negative tendency of winter (December, January, February) to spring (March, April, May) Darwin pressure anomaly was followed by a monsoon rainfall anomaly of less than minus one standard deviation; and only three instances (1916, 1933, 1961) when a positive tendency was followed by a rainfall anomaly of more than one standard deviation. Therefore, if the Darwin pressure anomaly during March, April and May is below normal, and if the Darwin seasonal pressure anomaly has been falling, a non-occurrence of drought over India can be predicted with a very high degree of confidence. Similarly, above normal Darwin pressure during March, April and May, and increasing seasonal pressure anomaly is a good indicator of the non-occurrence of very heavy rain over India.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1830-183
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  • 24
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    Stagnation-point ablation of carbonaceous flat disks. II Experiment (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Six flat-disk models made of carbon-carbon and carbon-phenolic materials were launched in an argon-filled track-range facility to test ablation characteristics in a radiation-dominated, massive-blowing environment. The shock standoff distances deduced from the shadowgraphs agree with theoretical predictions during the earlier portion of the flight, while the wall temperatures determined by the image-converter photographs agree with predictions during the later portion. The measured surface recessions exceed the calculated values by about 60 percent for carbon-phenolic and 30 percent for carbon-carbon. The discrepancies are attributed to spallation. The measured char thicknesses agree with theoretical predictions.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 21; 1748-175
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  • 25
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    Continuation in a parameter - Experience with viscous and free surface flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of modifications in continuation methods applied to obtain solutions to the Navier-Stokes systems of equations for incompressible, two-dimensional, steady flows are reported. It is shown that parameter continuation permits prediction of accurate, initial estimates for iterative processing of nonlinear finite difference and finite element equations of motions. The new parameter steps are derived from values of the preceding parameter steps. The accuracy of the estimates is ensured with appropriate choices of the step size. The continuation predictor/iterative corrector is demonstrated to trace the branches of parameter space along which steady flow states are found, and techniques are available for tracing multiply branching paths. The techniques are applied to solving the Navier-Stokes equations for flow through a rotating square channel, the formation of a falling liquid curtain, and gyrostatic equilibria of rotating cylindrical drops.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 26
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    Modeling of transient two-component flow using a four-point implicit method (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The four-point, centered implicit scheme that is extensively used in open channel flow simulation is shown to be applicable to rapid and slow pressure transient problems in conduits with nearly single phase and two-phase flows. It is only necessary to choose the proper weighting factor value, theta, of the Courant number. For rapid pressure transients such as waterhammer, the implicit method can yield reasonable results with limited numerical dispersion and attenuation if theta is only slightly greater than the critical value of 0.5. For slower pressure gradients in single and two-phase flows, reasonable numerical solutions may be achieved for Courant number values as high as 20.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 27
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    The utilization of Nimbus-7 SMMR measurements to delineate rainfall over land (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Approaches for developing an improved passive microwave technique to delineate rain from wet land surfaces are considered, and an investigation is conducted with the objective to study the application of these ideas with empirical data. The investigation includes a statistical analysis of Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) 37.0, 18.0, and 10.7 GHz data. The possibility was assessed to make use of the 18.0 and 10.7 GHz channels in order to reduce the ambiguities found in the 37.0 GHz radiometer data for differentiating rainfall areas from wet land surfaces. It was found, however, that none of the SMMR channels could differentiate rain from wet or dry land when surface temperatures were less than 15 C. It appears that an improved rainfall-over-land detection technique could be developed by two different methods, utilizing both satellite infrared and multifrequency dual polarized passive microwave data.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 1753-176
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  • 28
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    Light extinction by aerosols during summer air pollution (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In order to utilize satellite measurements of optical thickness over land for estimating aerosol properties during air pollution episodes, the optical thickness was measured from the surface and investigated. Aerosol optical thicknesses have been derived from solar transmission measurements in eight spectral bands within the band lambda 440-870 nm during the summers of 1980 and 1981 near Washington, DC. The optical thicknesses for the eight bands are strongly correlated. It was found that first eigenvalue of the covariance matrix of all observations accounts for 99 percent of the trace of the matrix. Since the measured aerosol optical thickness was closely proportional to the wavelength raised to a power, the aerosol size distribution derived from it is proportional to the diameter (d) raised to a power for the range of diameters between 0.1 to 1.0 micron. This power is insensitive to the total optical thickness. Changes in the aerosol optical thickness depend on several aerosol parameters, but it is difficult to identify the dominant one. The effects of relative humidity and accumulation mode concentration on the optical thickness are analyzed theoretically, and compared with the measurements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 1694-170
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  • 29
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    The production of turbulent stress in a shear flow by irrotational fluctuations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper examines, both theoretically and experimentally, the effect produced by irrotational fluctuations, associated with a nearby turbulent field, in a region where the turbulence is initially very low but where there is a mean shear. Calculations are based on rapid distortion theory and experiments use linearized hot wire anemometers in an open circuit wind tunnel. Turbulent shear stress is observed to grow from zero to significant values in the interaction region. The magnitude and extent of this observed shear stress agree reasonably well with predictions of the analysis, when intermittency effects are included. It is concluded that turbulent stresses can be produced by irrotational fluctuations in a region of mean shear and that this effect can be estimated using rapid distortion theory if the overall strain ratio is not large.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 30
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    A modified Dodge algorithm for the parabolized Navier-Stokes equations and compressible duct flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A revised version of Dodge's split-velocity method for numerical calculation of compressible duct flow was developed. The revision incorporates balancing of mass flow rates on each marching step in order to maintain front-to-back continuity during the calculation. The (checkerboard) zebra algorithm is applied to solution of the three dimensional continuity equation in conservative form. A second-order A-stable linear multistep method is employed in effecting a marching solution of the parabolized momentum equations. A checkerboard iteration is used to solve the resulting implicit nonlinear systems of finite-difference equations which govern stepwise transition. Qualitative agreement with analytical predictions and experimental results was obtained for some flows with well-known solutions. Previously announced in STAR as N82-16363
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Fluids (ISSN 0271-2091); 3; 493-506
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    An analysis of the 'Blizzard of '88' (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The analysis of the blizzard, an intense cyclone that was accompanied by unusually heavy snowfall, high winds, and cold temperatures, is carried out using a collection of detailed surface weather observations. It follows the cyclone from its genesis along a slow-moving frontal system through its rapid development and occlusion along the Middle Atlantic and southern New England coasts. Unusual aspects of the cyclone are discussed. Among these are the limited areal extent of heavy snow accumulations, the establishment of very cold air across western New England and the Middle Atlantic states, a persistent stationary front zone across central New England that separated frigid continental air from maritime air, and the slow movement and rapid warming associated with the decay of the storm.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 64; 1258-127
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  • 32
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    Stratospheric water vapor variability for Washington, DC/Boulder, CO - 1964-82 (1983)
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    Publication Date: 2011-08-18
    Description: Measurements for Washington, DC and Boulder, CO are combined to provide a time series of midlatitude stratospheric water vapor data for the period 1964-82. The mean concentration for the data period is shown to be nearly constant with altitude for the low stratospheric layer between 16-22 km with a mass mixing ratio for the layer of 2.5-2.6 ppmm. Above 22 km the mixing ratio increases slightly with altitude. Evident in the 60 mb level time series is an annual cycle, a quasi-biennial cycle and a long-term nonlinear trend. The quasi-biennial cycle in water vapor at midlatitudes is consistent with variations in tropical stratosphere zonal winds and temperature and total ozone and suggests a modulation of the Hadley cell circulation. The long-term trend shows mixing ratio increasing during the 1960s and decreasing in the 1970s after 1972.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; 2157-216
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    A satellite stereoscopic technique to estimate tropical cyclone intensity (1983)
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    Publication Date: 2011-08-18
    Description: The techniques used to obtain the mean equivalent temperature of the eye wall for Hurricanes Frederic (1979) and Allen (1980) using GOES satellite IR and stereoscopic observations are described. The eye wall is the area of greatest convection near the center of the storm, and is bounded by the inner radius around the eye and the outer radius bounding the area of inner core convection. The stereoscopic capability afforded by the GOES West and East spacecraft permits simultaneous, two-view imagery of a tropical cyclone, yielding height measurement accuracies of 0.5 km and horizontal accuracies as small as 1 km. An airborne lidar unit was used to verify the height measurements made of Hurricane Frederic. At the same time, the GOES East Visible IR Spin Scan Radiometer (VISSR) provided the mean wall temperatures from the release of latent heat. The trials aided in identifying the assumptions and consequent inaccuracies introduced into the temperature sounding data during analysis. The satellite data is concluded useful for monitoring changes in storm intensity.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 1599-161
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  • 34
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    Accuracy of approximations to the Navier-Stokes equations (1983)
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    Publication Date: 2011-08-18
    Description: The systems of truncated differential equations that have been proposed to reduce the complexity and large computational costs of solutions to the full Navier-Stokes equations are considered. These systems are computationally efficient and capture all the physically relevant behavior. The systems follow a certain hierarchy: (1) the classical boundary-layer equations with specified edge properties (usually the streamwise pressure distribution); (2) the coupled boundary-layer/inviscid equations; (3) the so-called thin-layer equations that discard streamwise diffusion; and (4) the Navier-Stokes equations. Consideration is given to each of these approximations applied to an incompressible, laminar-separating flow at low and moderate Reynolds numbers. It is pointed out that for any flow or region of flow for which viscous-inviscid interaction effects are small, classical boundary-layer equations will provide a satisfactory description of the viscous flow at a fraction of the computational cost of any higher approximations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 21; 1759
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  • 35
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    Growth of Goertler vortices in compressible boundary layers along curved surfaces (1983)
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    Publication Date: 2011-08-19
    Description: An investigation of the growth of the three-dimensional, counter-rotating, longitudinal type vortices is considered in two-dimensional laminar compressible boundary-layer flow. The basic approximation of the disturbance equations that includes the terms due to boundary layer growth is considered and solved numerically. These terms are shown to have large local effects near the neutral stability region. The study shows that the instability of the boundary layer with respect to the three-dimensional vortices sets in at higher Goertler number as Mach number increases. Also the maximum amplitude ratio of the vortices is reduced by about 20 percent as Mach number increases from 0 to 5.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Engineering and Applied Sciences (ISSN 0191-9539); 2; 3, 19; 213-238
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  • 36
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    Future research contributions of the VAS (1983)
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    Publication Date: 2011-08-18
    Description: The VAS data which are used for studying and predicting numerous meteorological phenomena are discussed. These phenomena include severe local storm antecedent conditions, the formative stages of tropical cyclones, the definition of upper tropospheric circulation features, and as input to synoptic scale prediction models.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 49-50
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    Some potential research applications of GOES/VAS data in meteorology (1983)
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    Publication Date: 2011-08-18
    Description: The understanding and utilization of radiance data from the VAS instrument for meteorological purposes which requires an extensive and organized research plan whose ultimate goal is to provide quantitative measurements of the structure/dynamics of the atmosphere is outlined. The unique multispectral VAS data are potentially useful in almost all aspects of meteorology but have immediate applications in the mesoscale and severe storm research area since measurements are available over regional areas at time intervals of less than 1 hour. The higher priority research applications of VAS data pertaining to the interpretation and utilization of the passive VAS radiance measurements for mesoscale and severe-storm research are reviewed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 51-52
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    VAS applications at Colorado State University (1983)
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    Publication Date: 2011-08-18
    Description: The application of the VAS program is outlined. The initial assessments of VAS radiometer and satellite performance were satisfactory; and VAS operations were smoothly carried out by the NESS SOCC and associated processing and retransmission facilities. The availability of advanced image processing systems, previous studies with the geosynchronous European Space Agency Meteorological Satellite (Meteosat), and the polar orbiter multichannel radiance data enabled the progress of the application. The VAS data are implemented as these data are received in the real time VISSR mode, and as dwell sounding (DS) and multispectral imaging (MSI) radiances on magnetic tapes.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 45-47
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  • 39
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    AVE/VAS experiment: Ground truth network (1983)
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    Publication Date: 2011-08-18
    Description: The visible/infrared spin scan radiometer (VISSR) atmospheric sounder (VAS) rawinsonde field program is discussed. Specific items covered include: planning, personnel requirements and training, operational requirement and procedures, sounding times and dates, methods of data processing, data inventory, and status of data processing.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 37-38
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  • 40
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    AVE/VAS experiment: Synoptic summary and preliminary results (1983)
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    Publication Date: 2011-08-18
    Description: The AVE/VAS ground truth field experiment was conducted during the Spring of 1982 severe storms and weather research program. The experiment consisted of acquiring correlative ground truth measurements of rawinsonde data, corresponding to the time and space resolutions of VAS sounding data. The objectives of the AVE/VAS experiment are: (1) to acquire four dimensional data sets of the actual atmospheric structure down to the mesoscale; (2) to provide measurements for quantitative comparisons between ground based and VAS-derived atmospheric parameters; (3) to evaluate the impact of VAS data on diagnostic analysis of structural features and dynamical processes important to the development of mesoscale phenomena; (4) to evaluate the impact of VAS data on numerical model simulations, nowcasting, and other mesoscale forecasting systems.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 39-43
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  • 41
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    Correlation of 3 hour radiosonde data with coincident Nimbus-7 total ozone measurements (1983)
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    Publication Date: 2011-08-18
    Description: A special network exercise supporting the VAS demonstration is reported. The second near-real time total ozone mapping spectrometer (TOMS) activity involving out of sequence processing of Nimbus-7 data over the United States and Europe is presented. The ozone data maps were used by airlines to search for regions of clear air turbulence and by an aircraft data gathering program, for synoptic upper air and tropopause height analyses. The TOMS total ozone levels are correlated with radiosonde tropopause height for testing the ability of TOMS data to give independent satellite measurements of tropopause height.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 31
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  • 42
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    VAS temperature retrievals for NASA special network observations of 6 March 1982 (1983)
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    Publication Date: 2011-08-18
    Description: VAS retrieval capability was studied. A mesoscale event consisting of a rapidly moving temperature perturbation with strong horizontal wind shear but shallow vertical extent occurred over Texas. The mesoscale event passed through the special radiosonde network and was documented with three hourly measurements. The event occurred behind a cold frontal cloud band during clear conditions. The event was accompanied by large skin temperature changes as the day progressed. This combination allows the testing of two important aspects of the retrieval algorithms with minimal cloud contamination and good ground truth. The first aspect concerns the horizontal and vertical resolving power of the retrievals and the second aspect concerns sensitivity to the boundary term. The NASA special network radiosonde is proven to be useful. It is demonstrated that: the VAS is capable, of delineating a mesoscale, normal retrieval procedure has the deficiency of oversmoothing, but this can be corrected, to document first quess dependence, and a superior data set to evolve better techniques for treating the surface boundary problem.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 33-36
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    Evaluation of the effect of VAS data on some NMC analyses and forecasts (1983)
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    Publication Date: 2011-08-18
    Description: The effect of visible/infrared atmospheric sounder (VAS) data on the limited area fine mesh model (LFM) analysis forecast system were examined. The VAS data obtained from the Pacific geostationary satellite are valuable for LFM analysis because temperatures from the polar orbiting satellite over the east Pacific are received too late for 1200 GMT LFM analysis. Because the VISSR has only infrared channels, retrievals are possible only in regions with little or no cloudiness.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 27-28
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  • 44
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    Use of the VAS water vapor imagery to analyze upper-level flow patterns (1983)
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    Publication Date: 2011-08-18
    Description: Infrared (IR) channels which are available and are developed for operational use were examined. The Visible Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS) was launched. This instrument has a radiometer consisting of the standard visible channel detectors and six thermal detectors that detect IR radiation in 12 spectral bands. Any one of the 11 new IR channels can be substituted for the standard 11.5 micro m window channel when the satellite is operating in the standard VISSP mode and provides data in image form through the GOES distribution system.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 29-30
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  • 45
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    Specifying heights and velocities of cloud motion from geostationary sounding data (1983)
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    Publication Date: 2011-08-18
    Description: Data from the geostationary Visible Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS) for assigning simultaneous heights and velocities of cloud motion winds were processed. The following two techniques are discussed: The technique which delivers qualitative height assignments from imagery; and which uses the radiometric information contained in the VAS data to calculate quantitative heights.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 25-26
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    VAS operational procedures and results at the Kansas City Satellite Field Services Station (1983)
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    Publication Date: 2011-08-18
    Description: An operational assessment of VAS data by using a Man-computer Interactive Data Access System (McIDAS) terminal linked by a 9600 band telephone line is discussed. Seven hours of VAS data were processed and edited daily. Data was scheduled 16 hours a day, 7 days a week; however, during this time period there were very few days with 16 hours of data to evalute. The McIDAS terminal, which has 10 display frames and 5 graphics, provide access to the sounding data processed. These data are processed using two procedures. The dwell sounding data are generated by using all 12 spectral channels with a spin budget of 39. To provide coverage for most of the United States, soundings are made starting at 18 minutes after the hour from approximately 49 deg N to 36 deg N and at 48 minutes after the hour from 36 deg N to 26 deg N. The dwell imaging mode uses 11 channels but the spin budge is 17. With the reduced spin budget, retrievals can be made at 18 or 48 minutes after the hour for approximately 44 deg N to 27 deg N. With these constraints a schedule, of data sets was proposed to use the schedule and how the data set could be used are shown.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 21-24
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  • 47
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    VAS assessment status and preliminary results (1983)
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    Publication Date: 2011-08-18
    Description: The VAS soundings, produced in real time on an hourly basis, consistently delineate the areas of the country where intense convective weather will occur several hours in advance of the severe weather developments. This conclusion is based on the daily experience gained. An objective method of forecasting the probability of severe weather for 100 kilometer square areas of the United States from the VAS soundings was presented. An example sequence of these probability forecasts and the subsequent observed severe weather is included.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Goddard Space Flight Center VISSR Atmospheric Sounder (VAS) Res. Rev.; p 17-19
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  • 48
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    The inference of tropical cyclone dynamics using GOES VISSR/VAS data (1983)
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    Publication Date: 2011-08-18
    Description: The sequence of events observed during tropical cyclone Emily, was suggested as a possible mechanism for cyclogenesis. Geostationary Operational Environmental Satellite (GOES) East VISSR/VAS sensors were used. The VISSR visible imagery obtained every 15 minutes was used to define the low tropospheric cyclonic vortex and upper tropospheric horizontal convergence. The VAS water vapor (channels 9 and 10) and carbon dioxide (channels 3 and 4) channels were used to infer upper and middle tropospheric subsidence by monitoring the Adiabatic compressional drying and warming, respectively, occurring within this layer. Evidence of an existing lower tropospheric cyclonic vortex was seen. The satellite derived wind vectors (length of vector is proportional to wind velocity, where the strongest winds were approximately 35 knots) are superimposed on the GOES visible image of tropical storm Emily. Vectors and low level clouds depict the center of the cyclonic vortex immediately south of the large convective cell in the center of the image. Upper tropospheric cloud tracers and rawinsonde reports along the Eastern United States suggest that the southwesterly environmental upper atmospheric flow is converging with the outflow from the convective cell north of the vortex.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 13-16
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    Analysis of multispectral data using an unsupervised classification technique: Application to VAS (1983)
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    Publication Date: 2011-08-18
    Description: A statistical classification method based on clustering of multidimensional histograms was applied to several channels of the VAS multispectral imagery. The method automatically discriminates and classifies atmospheric ground features such as cloud types, atmospheric moisture patterns, ocean, or ground. Such a clustering method has the advantage of forming natural data groupings, without a priori classification. Clusters are not limited by straight lines or plane surfaces as is the case in threshold methods. The method was applied to simultaneous full resolution images from channels 8 (11.2 micron), 10 (6.7 micron), and 12 (3.9 micron). Twenty image segments of 64 by 64, 12 image segments of 128 by 128, and 4 image segments of 254 by 254 picture elements were analyzed. In addition, normal VISSR mode images at 1800, 1830, and 2000 GMT were used to identify the classes. The gray levels measured along a scan line and the result of the classification scheme (dashed curves) for the three channels investigated are shown. Each point of the image is affected to a class. Each class is identified by a center of gravity that is represented by a vector in the three dimensional space of gray levels.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 11-12
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    Use of the VAS for analysis of a prethunderstorm environment (1983)
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    Publication Date: 2011-08-18
    Description: The information content of the VAS radiances can be converted to meteorological parameters useful for analyzing a severe weather environment. The method by which the VAS variances are converted to vertical profiles of temperature, dewpoints, and equivalent potential temperature involves a basic regression technique using the most local radiosonde data available for establishing a correlation matrix. The results indicate that mesoscale features apparent within images of the radiances can be converted to usable temperature and moisture fields using regression when surface temperature and dewpoint observations are included within the total data base. In addition, results indicate that surface data are very important for better defining lower tropospheric structure that the VAS radiances alone cannot properly resolve. Analyses of these retrievals distinctly show mesoscale structure in the temperature and moisture fields derived with VAS radiances collected every 3 hours, and 0000 GMT. The retrievals capture the moisture structure. More important, convective instability is clearly detected immediately before the onset of convection. The results indicate that the VAS is capable of providing valuable mesoscale information suitable for analyzing a preconvective environment that is generally clear.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 9
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    Diagnosing convective instability using VAS data (1983)
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    Publication Date: 2011-08-18
    Description: The utility of combining visible and various infrared images from the VAS to produce a forecasting tool, that can be available on a near real time basis, to predict severe weather development is shown. Areas where dry air in the midtroposphere overlays substantial moisture at low levels are used to diagnose mesoscale regions that have the potential for being convectively unstable before the onset of severe convection. Specifically, 6.7 micron water vapor imagery, used for isolating regions of substantial midlevel dryness, are combined with images of low level clouds or with split-window low level moisture images to delineate regions that have the potential for convective instability. In areas where scattered low level clouds are present, computer generated, color image combinations are used to isolate those warm, low level clouds that are in potential convectively unstable environments from clouds that exist under a deeply moist atmosphere. In clear regions, the split window technique is used for delineating areas of substantial boundary layer moisture. These images are again computer overlayed by the midlevel dryness to produce a color coded image of potential convective instability.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 7
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  • 52
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    Low-level water vapor fields from the VAS split-window channels at 11 and 12 microns (1983)
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    Publication Date: 2011-08-18
    Description: Originally, the VAS split window channels were designed to use the differential water vapor absorption between 11 and 12 microns to estimate sea surface temperature by correcting for the radiometric losses caused by atmospheric moisture. It is shown that it is possible to reverse the procedure in order to estimate the vertically integrated low level moisture content with the background surface (skin) temperature removed, even over the bright, complex background of the land. Because the lower troposphere's water vapor content is an important factor in convective instability, the derived fields are of considerable value to mesoscale meteorology. Moisture patterns are available as quantitative fields (centimeters of precipitable water) at full VAS resolution (as fine as 7 kilometers horizontal resolution every 15 minutes), and are readily converted to image format for false color movies. The technique, demonstrated with GOES-5, uses a sequence of split window radiances taken once every 3 hours from dawn to dusk over the Eastern and Central United States. The algorithm is calibrated with the morning radiosonde sites embedded within the first VAS radiance field; then, entire moisture fields are calculated at all five observation times. Cloud contamination is removed by rejecting any pixel having a radiance less than the atmospheric brightness determined at the radiosonde sites.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 5-6
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    System description (1983)
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    Publication Date: 2011-08-18
    Description: The VAS, carried onboard the GOES 4 and 5 satellites, is a radiometer with 8 visible channel detectors and 6 thermal detectors that detect infrared radiation in 12 spectral bands. A filter wheel in front of the detector is used to achieve the spectral selection. The spatial resolution is 0.9 kilometer in the visible and 7 or 14 kilometers in the infrared depending on the detector used. Full Earth disk coverage is accomplished by spinning in the west to east direction at 100 rpm and by stepping a scan mirror from north to south. Additional VAS instrument characteristics are summarized. The VAS has three operating modes: the operational VISSR mode, the multispectral imaging (MSI) mode, and the dwell sounding (DS) mode. The operational VISSR mode is used by NOAA/NESS for its operational products, which include a visible picture and an 11 micrometer infrared (channel 8) picture at half hour intervals. The other modes are VAS unique. The MSI mode combines the operational VISSR capability (visible plus infrared window) with two additional spectral channels to provide half hourly full Earth disk imagery of atmospheric water vapor, temperature, and cloud distribution. The DS mode is used primarily for sounding to obtain the temperature and moisture profiles. In this mode, multiple spins on the same scan line in a given band are averaged to obtain the required signal to noise ratio for sounding.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: VISSR Atmospheric Sounder (VAS) Res. Rev.; p 1-3
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    Clear-sky radiative characteristics of South America derived from geostationary satellite data (1983)
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    Publication Date: 2011-08-18
    Description: Estimates of clear-sky albedo and equivalent blackbody temperatures derived from the Geostationary Operational Environment Satellite are presented. Regional clear-sky albedo over South America at noon ranged from 10 to 22 percent during November 1978 and February 1979, mean clear-sky albedo over the continent remained fairly constant at about 12.4 percent. A slight seasonal decrease in albedo found in a number of large river valleys is attributed to seasonal flooding. The average clear-sky albedo varied diurnally by factors of 2.0 and 2.3 from the value at noon over desert and vegetated areas, respectively. The mean regional clear-sky equivalent blackbody temperature ranged from 283 to 295 K.
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    Diurnal cloud variations over South America and the southeastern Pacific (1983)
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    Publication Date: 2011-08-18
    Description: The changing distributions of cloud cover are of particular importance in understanding the general circulation patterns of the Southern Hemisphere, whose prediction is hampered by the sparse sampling of physical qualities. In near-tropical areas, the diurnal solar heating cycle is noted to be directly responsible for many of the observed weather patterns. Among the atmosphere's familiar responses to this heating cycle are afternoon thunderstorms over tropical land areas and the 'burnoff' of morning fog or low stratus near coastal margins. Attention is given to these aspects of the atmospheric adjustment to the daily solar cycle in terms of regional scale mean cloudiness over part of the Southern Hemisphere.
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    FGGE forecast impact studies in the Southern Hemisphere (1983)
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    Details
    Publication Date: 2011-08-18
    Description: The purpose of this paper is to quantify the impact of the FGGE SOS on the GLAS analyses and forecasts in the Southern Hemisphere, and to evaluate the relative importance of its components, and in particular, the impact of the loss of surface buoys. This discussion is limited to the forecast impact of the FGGE system upon a region between 28 deg S and 56 deg S, 50 deg W-80 W which includes essentially the southern cone of South America. Although forecast skill is verified against the NMC analysis, which used only VTPR but no TIROS-N data in the Southern Hemisphere, enough conventional data exists over this region to avoid biased verifications.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Large amplitude stationary Rossby waves in the southern hemisphere - Observations and theory (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Further observational evidence is presented for the existence of large amplitude short stationary waves during the month of January, 1979 in the lee side of South America. These waves are noted not to have been produced by either topography or CISK; their cause was probably related to stronger tropical convective heating over the Amazon and central Pacific during January. This source of stationary forcing was associated with the weaker easterlies and stronger westerlies in the topics, which allowed free propagation of the energy from the stationary forcing into the extratropics.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Persistent anomalies of the Southern Hemisphere circulation (1983)
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    Publication Date: 2011-08-18
    Description: The persistent features of large anomalies have been examined and the locations of blocking in the Southern Hemisphere were determined. The data set used here contains daily maps of 500 mb geopotential heights for 100 months (June 1, 1972 to Nov. 30, 1980) covering from 10S to 90S. The seasonal cycle was defined as a 8 year mean and the 8th (annual) and 16th (semiannual) Fourier components of the time series at each grid point. Anomalies were defined as the difference between the total field and the seasonal cycle for each grid point.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    The simulation of the seasonal cycle of the Southern Hemispheric circulation by the GLAS Seasonal Cycle Model and a comparison to observations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The general circulation of the Southern Hemisphere is quite different from that of the Northern Hemisphere in many important ways. These include the barotropic nature of the stationary waves and the presence of a strong barotropic component to the mean zonal wind, the lack of a strong seasonal dependence of the transient eddies, and the dominant role played by eddies with periods less than 10 days compared to longer period fluctuations. Such differences attest to the importance of the altered nature of the orographic and thermal land-sea forcings in the Southern Hemisphere compared to the Northern Hemisphere. Some of the important features of the Southern Hemisphere circulation as simulated by the GLAS Seasonal Cycle Model (SCM) are presented. The geographical patterns of local variability and their seasonal shifts in the SCM are discussed and compared to observations.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Satellite data - Analysis techniques and applications to meteorology (1983)
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    Publication Date: 2011-08-18
    Description: The history of meteorological satellites is traced, together with current instrumental and data analysis capabilities. Photographs taken from rockets launched in the late 1950s encouraged placing spacecraft such as the Nimbus I in sunsynchronous orbit beginning in 1964, and eventually the GOES, GMS, TIROS and Meteosat spacecraft into GEO in the 1970s. Visible, UV, IR and microwave sensors provide data on cloud patterns, wind fields, vertical temperature and humidity profiles and the surface temperature. Corrections have been developed in the data analyses programs to account for the atmospheric effects on upwelling radiation, fractional cloudiness, cloud-top heights and cloud contamination factors.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Cumulus clouds - Early aircraft observations and entrainment hypotheses (1983)
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    Publication Date: 2011-08-18
    Description: The history of cumulus research in the decade following World War II is reviewed in the perspective of the new ideas and advances made during the subsequent generation. Emphasis is placed upon pioneering aircraft measurements, evidence for entrainment, the early model attempts and their attendant controversies.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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  • 62
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    Cumulus role in tropical circulations (1983)
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    Publication Date: 2011-08-18
    Description: The present investigation is concerned with the effects of cumulus clouds upon their surroundings, and the interaction of the cumulus scale of motion with the larger scales of motion in the tropics. Charney and Eliassen (1964) have conducted a study of the growth of the hurricane depression and proposed the CISK (Conditional Instability of the Second Kind) mechanism. The CISK concept was used in several of the pioneering models of hurricanes and tropical disturbances. Since the 1960's, the CISK concept has been generalized and extended. However, the feedback between convection and the large-scale flow is still positive. In the present investigation the philosophy is extended to a negative feedback which contributes to the stability (mainly in direction) of the trade winds. Attention is given to the classical Ekman layer and early CISK, cumulus momentum transports, the role of cumuli in the trade-wind moisture and heat budgets, the trade wind model, and the equatorial trough and hot tower hypothesis.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Finite element calculation of buoyancy-driven convection near a melt/solid phase boundary (1983)
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    Publication Date: 2011-08-18
    Description: Two iterative schemes based on the mixed finite element method are developed for analyzing steady natural convection in a melt adjacent to its solid phase. The simplest method decouples the calculation of the field variables and the shape of the melt/solid interface into two interlocked iterations that are performed successively. The second method uses Newton's iteration to solve simultaneously for both types of unknowns and has a quadratic convergence rate. Results for a model problem of melt and solid in a cylindrical ampoule show the Newton algorithm to be a factor of three more efficient.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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    Variational global analysis of satellite temperature soundings (1983)
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    Publication Date: 2011-08-18
    Description: A variational spherical harmonic analysis is developed for the production of global geopotential height and geostropic wind fields from the TIROS-N spacecraft's temperature sounding profiles. This scheme is based on Tykhonov's (1964) regularization method, and the smoothing parameter is determined by cross validation. The scheme is noted to be stable and computationally efficient, and it does not depend on a priori information. Its applications to three-dimensional temperature retrievals and to four-dimensional spectral analyses are illustrated.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    The effect of spatial resolution on the simulation of upper-tropospheric frontogenesis using a sigma-coordinate primitive equation model (1983)
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    Publication Date: 2011-08-18
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    An evaluation of the synoptic- and mesoscale predictability of the Mesoscale Atmospheric Simulation System (MASS 2.0) model (1983)
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    Publication Date: 2011-08-18
    Description: A report is presented regarding the synoptic- and mesoscale predictive capabilities of a regional-scale numerical weather prediction model known as the Mesoscale Atmospheric Simulation System (MASS, Version 2.0). The development of this model has been discussed by Kaplan et al. (1982). An evaluation of the performance of MASS 2.0 is based on the study of a sample of approximately thirty 12 h and 24 h forecasts of atmospheric flow patterns over the U.S. during spring and early summer of 1982. A description of model systems is provided, and synoptic-scale evaluation methods are considered along with aspects of mesoscale evaluation methodology, examples of coherent mesoscale information provided by MASS 2.0, the results of a diagnostic study of mesoscale convective systems (MCS), and the results of a limited real-time forecast experiment.
    Keywords: METEOROLOGY AND CLIMATOLOGY
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    Multiple-grid convergence acceleration of viscous and inviscid flow computations (1983)
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    Publication Date: 2011-08-18
    Description: A multiple-grid algorithm for use in efficiently obtaining steady solution to the Euler and Navier-Stokes equations is presented. The convergence of a simple, explicit fine-grid solution procedure is accelerated on a sequence of successively coarser grids by a coarse-grid information propagation method which rapidly eliminates transients from the computational domain. This use of multiple-gridding to increase the convergence rate results is substantially reduced work requirements for the numerical solution of a wide range of flow problems. Computational results are presented for subsonic and transonic inviscid flows and for laminar and turbulent, attached and separated, subsonic viscous flows. Work reduction factors as large as eight, in comparison to the basic fine-grid algorithm, were obtained. Possibilities for further performance improvement are discussed. Previously announced in STAR as N83-21847
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Applied Mathematics and Computation (ISSN 0096-3003); 13; 375-398
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    A statistical examination of Nimbus-7 SMMR data and remote sensing of sea surface temperature, liquid water content in the atmosphere and surface wind speed (1983)
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    Publication Date: 2011-08-18
    Description: Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) brightness temperature measurements over the global oceans have been examined with the help of statistical and empirical techniques. Such analyses show that zonal averages of brightness temperature measured by SMMR over the oceans on a large scale are primarily influenced by the water vapor in the atmosphere. Liquid water in the clouds and rain, which has a much smaller spatial and temporal scale, contributes substantially to the variability of the SMMR measurements within the latitudinal zones. The surface wind not only increases the surface emissivity, but through its interactions with the atmosphere produces correlations in the SMMR brightness temperature data that have significant meteorological implications. It is found that a simple meteorological model can explain the general characteristics of the SMMR data. With the help of this model, methods to infer over the global oceans, the surface temperature, liquid water content in the atmosphere, and surface wind speed are developed. Monthly mean estimates of the sea surface temperature and surface winds are compared with the ship measurements. Estimates of liquid water content in the atmosphere are consistent with earlier satellite measurements. Previously announced in STAR as N83-19187
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 2023-203
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    The impact of conventional surface data upon VAS regression retrievals in the lower troposphere (1983)
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    Publication Date: 2011-08-18
    Description: Surface temperature and dewpoint reports are added to the infrared radiances from the VISSR Atmospheric Sounder (VAS) in order to improve the retrieval of temperature and moisture profiles in the lower troposphere. The conventional (airways) surface data are combined with the twelve VAS channels as additional predictors in a ridge regression retrieval scheme, with the aim of using all available data to make high resolution space-time interpolations of the radiosonde network. For one day of VAS observations, retrievals using only VAS radiances are compared with retrievals using VAS radiances plus surface data. Temperature retrieval accuracy evaluated at coincident radiosonde sites shows a significant impact within the boundary layer. Dewpoint retrieval accuracy shows a broader improvement within the lowest tropospheric layers. The most dramatic impact of surface data is observed in the improved relative spatial and temporal continuity of low-level fields retrieved over the Midwestern United States. Previously announced in STAR as N83-27522
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; 1853-187
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    The parameterization of the planetary boundary layer in the UCLA general circulation model - Formulation and results (1983)
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    Publication Date: 2011-08-18
    Description: A planetary boundary layer (PBL) parameterization for general circulation models (GCMs) is presented. It uses a mixed-layer approach in which the PBL is assumed to be capped by discontinuities in the mean vertical profiles. Both clear and cloud-topped boundary layers are parameterized. Particular emphasis is placed on the formulation of the coupling between the PBL and both the free atmosphere and cumulus convection. For this purpose a modified sigma-coordinate is introduced in which the PBL top and the lower boundary are both coordinate surfaces. The use of a bulk PBL formulation with this coordinate is extensively discussed. Results are presented from a July simulation produced by the UCLA GCM. PBL-related variables are shown, to illustrate the various regimes the parameterization is capable of simulating.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; 2224-224
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    NASA's AVE/VAS program (1983)
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    Publication Date: 2011-08-18
    Description: A discussion is presented concerning the Atmospheric Variability Experiment (AVE) which was conducted during the spring of 1982 as part of NASA's Visible and Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS) demonstration. The AVE/VAS Ground Truth Field Experiment is examined in detail, which comprised the obtaining of rawinsonde observations during various meteorological conditions on four different days when VAS data were obtained. These experiments were performed over 24 hr periods in a mesoscale network of 24 National Weather Service rawinsonde sites and 13 NASA and NOAA special sites. The VAS, operating as a part of the GOES satellite system, was employed to provide two-dimensional cloud mapping capability during each of the AVE/VAS experiment periods. Among the goals of this AVE/VAS program, in addition to management of the acquisition and processing of the data, were to perform the research and development needed to produce data products from VAS radiances, to validate the data, and to assess the impact of the data on mesoscale meteorological forecasting and research requirements.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: American Meteorological Society, Bulletin (ISSN 0003-0007); 64; July 198
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  • 72
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    Atmospheric temperatures near the tropical tropopause Temporal variations, zonal asymmetry and implications for stratospheric water vapor (1983)
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    Publication Date: 2011-08-18
    Description: Analysis of temperature measurements obtained over an eight-year period in the vicinity of the low-latitude tropopause confirms the existence of longitude regions which are consistently colder by approximately 2-3 K than elsewhere in the tropics. These temperature differences, however, are confined to a layer of thickness 3-5 km centered on the tropopause. The lowest monthly mean temperatures observed at the colder stations yield saturation mixing ratios that are consistent with the range of measured stratospheric water vapor. Examination of the daily variations in temperature at a given station reveals a more complex pattern than indicated by the monthly averages. On many days temperatures at the colder longitudes correspond to water vapor abundances that are less than observed in the stratosphere despite the favorable comparison of the monthly means. The results point to the need for a series of water vapor soundings at selected longitudes and times in order to define the extent to which the tropical tropopause controls the stratospheric water vapor abundance.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; July 198
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    Relative frequency and diurnal variation of high cold clouds in the tropical Atlantic and Pacific (1983)
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    Publication Date: 2011-08-18
    Description: The percentage of cold clouds less than or equal to 240 K was tabulated from Nimbus-5 data in 2 deg latitude-longitude squares over tropical oceans in the North Atlantic and Pacific for day (1130 LST) and night (2330 LST). The maximum percentage and amplitude of the diurnal variation are in the eastern Atlantic and Pacific. Day percentages are higher than at night in the entire 6-10 deg N belt of the Atlantic. Weaker night maxima are to the north and south of this belt. In the Pacific, the distribution of day and night predominance is more variable.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; June 198
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    Interannual variability and predictability of 500 mb geopotential heights over the Northern Hemisphere (1983)
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    Publication Date: 2011-08-18
    Description: The interannual variability of monthly mean 500 mb heights in a 15-year sample of observed data is compared to the variance expected from sampling errors associated with high-frequency fluctuations using the analysis of variance approach. The monthly mean 'signal' stands out significantly from the 'noise' over a substantial fraction of the Northern Hemisphere during the winter. The expected spectrum of variance at very low frequencies is assumed to be white at frequencies lower than per (30 days) rather than the per (96 days) cutoff used by Madden. This difference is justified by observing that the effective time between independent samples T(0) is relatively insensitive to changes in the maximum lag over which the local autocorrelation is integrated to calculate T(0). Further non-randomness in the variance of 500 mb heights is evidenced by the correlation between monthly mean height and contemporaneous daily variability.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; June 198
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  • 75
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    Upper-level structure of Oklahoma tornadic storms on 2 May 1979. II - Proposed explanation of 'V' pattern and internal warm region in infrared observations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; July 198
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  • 76
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    Upper-level structure of Oklahoma tornadic storms on 2 May 1979. I - Radar and satellite observations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; July 198
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    Numerical simulation of the atmospheric response to equatorial Pacific sea surface temperature anomalies (1983)
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    Publication Date: 2011-08-18
    Description: There exists observational and modeling evidence to the effect that sea surface temperature (SST) anomalies in the equatorial Pacific have a significant effect upon wintertime climate in the Pacific/North American sector of the hemisphere. In connection with the emergence of a more definitive observational basis for designing general circulation model (GCM) experiments to investigate the atmospheric response to equatorial SST anomalies, it was recommended to conduct a series of GCM experiments. The present study involves a series of extended (1-2 month) integrations.Attention is given to a review of previous GCM experiments, the plan for the present study, the general circulation model and its simulation of the winter and summer circulation described by Shukla et al. (1981), tropical precipitation, upper level flow, low-level circulation and temperature, and the tropical tropospheric temperature.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; July 198
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    The shape, propagation and mean-flow interaction of large-scale weather systems (1983)
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    Publication Date: 2011-08-18
    Description: In investigations concerned with obtaining an understanding of the general circulation of the atmosphere, the determination of the role of the large-scale eddies presents a special problem. In the present study,attention is given to a theory which, in some ways, provides an extension of the Eliassen-Palm flux concept so that it can be applied in particular to the time-averaged three space dimension problem. Particular emphasis is given to the understanding of the feedback of the eddies onto the mean flow. However, the behavior of the eddies themselves is also discussed. It is shown that, in simple situations, the anisotropic eddy horizontal velocity correlation tensor implies the shape and propagation of eddies and the feedback of the eddies onto the mean flow.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; July 198
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    Effect of variable thermal conductivity on isotherms in Bridgman growth (1983)
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    Publication Date: 2011-08-18
    Description: A change in thermal conductivity associated with melting or solidification can have a profound influence on the isotherms near the solidification interface if the material is being directionally solidified in an ampoule whose walls carry a substantial portion of the heat. This analysis was prompted by a recent discovery that the thermal conductivity of Hg(1-x)CD(x)Te increased dramatically as the material is heated above the solidus curve. An illustrative example is shown in which the sample is approximated as an infinite cylinder with constant but diffferent thermal properties in the solid and melt. The boundary conditions are fixed on the surface by a conductive ampoule in a two-zone Bridgman furnace with an adiabatic region separating the two zones. The effect of the adiabatic zone in this case is to intensify the curvature of the interface rather than to lessen it.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Crystal Growth (ISSN 0022-0248); 61; Apr
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  • 80
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    Analysis of coolant entrance boundary shape of porous region to control cooling along exit boundary (1983)
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    Publication Date: 2011-08-18
    Description: A cooled porous region has a plane surface exposed to a specified spatially varying heat flux. The coolant leaves the region through this surface, and it is desired to control the flow distribution to maintain a specified uniform surface temperature. This is accomplished by having the coolant entrance surface shaped to provide in the region the necessary variation of path length and, hence, flow resistance. The surface shape at the coolant entrance is found by solving a Cauchy boundary value problem. An exact solution is obtained that will deal with a wide variety of heating distributions for both two- and three-dimensional shapes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASME, Transactions, Journal of Heat Transfer (ISSN 0022-1481); 105; Aug. 198
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    The geologic record of climatic change (1983)
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    Publication Date: 2011-08-18
    Description: Major results from paleoclimatic investigations are investigated, and background material is included. The time interval surveyed extends from the formation of the earth 4.6 billion years ago to the development of the instrumental record. Previously announced in STAR as N82-33946
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Reviews of Geophysics and Space Physics (ISSN 0034-6853); 21; May 1983
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  • 82
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    Efficient three-dimensional global models for climate studies - Models I and II (1983)
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    Publication Date: 2011-08-18
    Description: Climate modeling based on numerical solution of the fundamental equations for atmospheric structure and motion permits the explicit modeling of physical processes in the climate system and the natural treatment of interactions and feedbacks among parts of the system. The main difficulty concerning this approach is related to the computational requirements. The present investigation is concerned with the development of a grid-point model which is programmed so that both horizontal and vertical resolutions can easily be changed. Attention is given to a description of Model I, the performance of sensitivity experiments by varying parameters, the definition of an improved Model II, and a study of the dependence of climate simulation on resolution with Model II. It is shown that the major features of global climate can be simulated reasonably well with a horizontal resolution as coarse as 1000 km. Such a resolution allows the possibility of long-range climate studies with moderate computer resources.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review (ISSN 0027-0644); 111; April 19
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    A model to determine open or closed cellular convection (1983)
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    Publication Date: 2011-08-18
    Description: The horizontal asymmetry of cellular convection is demonstrated to be detectable by consideration of the vertical asymmetry of the driving force. A two-dimensional numerical model for convection in an internally heated and cooled fluid is presented, based on equations for the conservation of temperature and vorticity. Attention is focused on the steady-state finite-amplitude solutions for fixed Rayleigh number, Prandtl number, and aspect ratio. Temperature in the model corresponds to potential temperature under dry conditions and the equivalent potential temperature under saturated conditions. Slowly varying convection driven by asymmetric boundary fluxes is expressed in terms of steady-state convection driven by an asymmetric internal heat source. It is shown that heating near the ground produces open convection patterns where most of the fluid is descending, while cooling near the top of the flow leads to closed cellular patterns with a preponderance of ascending fluid. Extension of the model to three dimensions is indicated.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; March 19
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    Annual cycle and spatial spectra of earth emitted radiation at large scales (1983)
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    Publication Date: 2011-08-18
    Description: Monthly averaged, resolution enhanced global distributions of the earth's emitted radiation, as measured by the Nimbus-6 Earth Radiation Budget (ERB) wide field of view radiometers, have been analyzed for 1 year of data from July 1975 to June 1976. These distributions are expressed in terms of spherical harmonic coefficients, and time and space variability of the emitted radiation field is studied in terms of these coefficients. The average annual distribution accounts for 78 percent of the space-time power, and the annual cycle accounts for 17 percent of the power. Spatial variations over the globe are described in terms of degree variance, and longitudinal variations are described in terms of spectral power as a function of latitude. The longitudinal spectra were found to vary strongly with time.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of the Atmospheric Sciences (ISSN 0022-4928); 40; April 19
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    Numerical solutions for spin-up from rest in a cylinder (1983)
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    Publication Date: 2011-08-18
    Description: A set of three-dimensional flow-field data for the region around a cylinder impulsively spun-up from rest was derived with a numerical model based on the Navier-Stokes equations. Laser-Doppler anemometer data in the azimuthal direction was employed to test the model predictions, and data was developed for a flowfield with Ekman numbers from 9.18/1,000,000 to 9.18/10,000. The contributions of inviscid and viscous terms were determined as functions of radius and time. It was found that immediately after start-up viscous diffusion is the dominant factor, which is replaced by nonlinear radial advection. The Coriolis force dominates in the later stages of spin-up. The inward radial flow is a maximum near the front, where the vertical velocity is small, but features strong radial gradients, as it does at the edge of the Ekman layer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 127; Feb. 198
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    Procedure for generating ground wind environments for Shuttle liftoff studies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Ground-wind environments for Monte Carlo simulations of Space Shuttle liftoff at KSC are developed. Input parameters include randomly selected 18.3-m-altitude peak wind speed (from which mean wind profile and turbulence intensity are calculated), randomly selected mean wind direction, and longitudinal and lateral turbulence components obtained from the Shuttle-simulation turbulence tapes (SSTT: Tatom et al., 1982). The steps in the simulation of turbulence time histories and horizontal wind fields are listed. It is found that separate statistical analysis of each hour-season pair, applying data on the time fraction of occurrence of peak winds and wind directions at KSC, will be necessary to interpret simulation results consistently.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4560); 20; July-Aug
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  • 87
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    Profiling atmospheric water vapor by microwave radiometry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Journal of Climate and Applied Meteorology (ISSN 0733-3021); 22; May 1983
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  • 88
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    Diagnostic analysis and spectral energetics of a blocking event in the GLAS climate model simulation (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A synoptic and spectral analysis of a blocking event is presented, with attention given to the temporal evolution, maintenance, and decay of the block. The GLAS numerical climate model was used to generate a blocking event by the introduction of SST anomalies. Wavenumbers 2 and 3 became stationary around their climatological locations, and their constructive interference produced persistent blocking ridges over the west coast of North America and the other over western Europe. Time variations of the kinetic and potential energies and energy conversions during the blocking were performed. Spectrally filtered Hovmoller diagrams were developed for the winter of 1976-77, and showed that long waves were stationary over most of the interval, which featured severe weather conditions.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: Monthly Weather Review; 111; Jan. 198
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  • 89
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    The evolution of Tollmien-Schlichting waves near a leading edge (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The method of matched asymptotic expansions is used to study the generation of Tollmien-Schlichting waves by free-stream disturbances incident on a flat-plate boundary layer. Near the leading edge, the motion is governed by the unsteady boundary-layer equation, while farther downstream it is governed (to lowest order) by the Orr-Sommerfeld equation with slowly varying coefficients. It is shown that there is an overlap domain where the Tollmien-Schlichting wave solutions to the Orr-Sommerfeld equation and appropriate asymptotic solutions of the unsteady boundary-layer equation match, in the matched-asymptotic-expansion sense. The analysis explains how long-wavelength free-stream disturbances can generate Tollmien-Schlichting waves of much shorter wavelength. It also leads to a set of scaling laws for the asymptotic structure of the unsteady boundary layer.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics; 127; Feb. 198
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  • 90
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    Variability of rainfall over small areas (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A preliminary investigation was made to determine estimates of the number of raingauges needed in order to measure the variability of rainfall in time and space over small areas (approximately 40 sq miles). The literature on rainfall variability was examined and the types of empirical relationships used to relate rainfall variations to meteorological and catchment-area characteristics were considered. Relations between the coefficient of variation and areal-mean rainfall and area have been used by several investigators. These parameters seemed reasonable ones to use in any future study of rainfall variations. From a knowledge of an appropriate coefficient of variation (determined by the above-mentioned relations) the number rain gauges needed for the precise determination of areal-mean rainfall may be calculated by statistical estimation theory. The number gauges needed to measure the coefficient of variation over a 40 sq miles area, with varying degrees of error, was found to range from 264 (10% error, mean precipitation = 0.1 in) to about 2 (100% error, mean precipitation = 0.1 in).
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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  • 91
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    Sparger system for MMH-helium vents (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The 1983 NASA(ASEE Summer Faculty Fellowship Research Program Research Reports; 17 p
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  • 92
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    An analysis of cryotrap heat exchanger performance test data (400 area) and recommendations for a system to handle Apollo RCS engines (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The current arrangement of a Platecoil heat exchanger which uses LN2 on the inside of parallel tubes, in counter flow to the test cell engine exhaust gases which are drawn through a box surrounding the plates by the existing vacuum blowers is examined. As a result of inadequate performance and special test data it was decided to redesign the system to accommodate an Apollo RCS engine.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: The 1983 NASA(ASEE Summer Faculty Fellowship Research Program Research Reports; 15 p
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  • 93
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    Accuracy of vertical velocity determination (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Typical wind spectra taken at Poker Flat, Alaska, using the vertically oriented antenna show velocities of 10's of cm to meters per second and spectral widths winds of 0.5 to 1 m/s. The potential errors in such measurements can be broken down into three categories: (1) those due to instrumental parameters and data processing, (2) those due to specular returns from non-horizontal surfaces, and (3) those due to other physical effects. Error analysis in vertical velocity measurement is further discussed.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 227-231
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  • 94
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    Jet stream related observations by MST radars (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: An overview of the jet stream and its observation by MST radar is presented. The climatology and synoptic and mesoscale structure of jet streams is briefly reviewed. MST radar observations of jet stream winds, and associated waves and turbulence are then considered. The possibility of using a network of ST radars to track jet stream winds in near real time is explored.
    Keywords: METEOROLOGY AND CLIMATOLOGY
    Type: International Council of Scientific Unions Middle Atmosphere Program, Vol. 9; p 12-21
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  • 95
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    Jet array impingement heat transfer characteristics (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Two dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. In addition to the crossflow which originates from the jets following impingement, an initial crossflow is present which approaches the array through an upstream extension of the channel. The configurations considered are intended to model the impingement cooled midchord region of gas turbine airfoils in cases where an initial crossflow is also present. A major objective is determination of the effect of initial crossflow air temperature relative to jet array air temperature on impingement surface heat fluxes.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center Turbine Eng. Hot Sect. Technol. (HOST); p 117-128
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    Coolant passage heat transfer with rotation. A progress report on the computational aspects (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Turbine airfoils are subjected to increasingly higher heat loads which escalate the cooling requirements in order to satisfy life goals for the component materials. If turbine efficiency is to be maintained, however, cooling requirements should be as low as possible. To keep the quantity of cooling air bounded, a more efficient internal cooling scheme must be developed. One approach is to employ airfoils with multipass cooling passages that contain devices to augment internal heat transfer while limiting pressure drop. Design experience with multipass cooling passage airfoils has shown that a surplus of cooling air must be provided as a margin of safety. This increased cooling air leads to a performance penalty. Reliable methods for predicting the internal thermal and aerodynamic performance of multipass cooling passage airfoils would reduce or eliminate the need for the safety margin of surplus cooling air. The objective of the program is to develop and verify improved analytical methods that will form the basis for design technology which will result in efficient turbine components with improved durability without sacrificing performance. The objective will be met by: (1) establishing a comprehensive experimental data base that can form the basis of an empirical design system; (2) developing computational fluid dynamic techniques; and (3) analyzing the information in the data base with both phenomenological modeling and mathematical modeling to derive a suitable design and analysis procedure.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center Turbine Eng. Hot Sect. Technol. (HOST); p 111-116
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    A Study of Accretion in Compact Sources: Disk Precession and Jet Helicity (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-11
    Description: The effect of adiabatic expansion on the propagation and growth of helical twisting on a supersonic jet is investigated. Cooling of the jet material increases the jet's Mach number and increases the jet's density relative to that of the external medium. This has the effect of decreasing the maximum rate of growth and increasing the maximally unstable wavelength relative to the jet's radius. Propagation effects cause the wavelength of helical waves to change at a rate different from that of the maximally unstable wavelength with the result that the characteristic wavelength of helical twisting is not equal to this wavelength. The most rapidly growing helical wave will have a wavelength as much as a factor of 2 different from the instantaneous maximally unstable wavelength.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 39 p
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  • 98
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    A Numerical Investigation of the Multiple Vortex Phenomenon: Vortex Number and Structure as a Function of Swirl Ratio (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-12
    Description: A numerical investigation of the multiple vortex phenomenon (MVP) for tornado like flows is conducted to determine the conditions for when a vortex becomes unstable and divides into smaller subsidiary vortices, as well as to determine the structure of these vortices. A three dimensional numerical model developed by Rotunno (1983) is utilized which has been demonstrated to successfully simulate MVP with properties observed both in natural as well as laboratory tornado like vortices. The MVP is generated for several swirl ratio conditions in order to determine the number of vortices generated for those flow configurations. These results are then compared to experimental measurements to validate the numerical model. The number of vortices produced is consistent with observational results made in the Purdue tornado vortex chamber. Furthermore, horizontal and vertical cross sections are taken through the vortices to determine the structure of MVP. Preliminary results indicate that tangential velocities within these smaller asymmetric vortices increase by 20% over values observed in a single axisymmetric vortex at the same swirl ratio.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 28 p
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  • 99
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    A comparative study of time-marching and space-marching numerical methods (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Menees (1981) has conducted an evaluation of three different flowfield codes for the Jupiter entry conditions. However, a comparison of the codes has been made difficult by the fact that the three codes use different solution procedures, different computational mesh sizes, and a different convergence criterion. There are also other differences. For an objective evaluation of the different numerical solution methods employed by the codes, it would be desirable to select a simple no-blowing perfect-gas flowfield case for which the turbulent models are well established. The present investigation is concerned with the results of such a study. It is found that the choice of the numerical method is rather problem dependent. The time-marching and the space-marching method provide both comparable results if care is taken in selecting the appropriate mesh size near the body surface.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal; 21; Jan. 198
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    Airborne operation of an infrared low-level wind shear prediction system (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 06, p. 921, Accession no. A82-17810)
    Keywords: METEOROLOGY AND CLIMATOLOGY
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