216
216
Jul 11, 2010
07/10
by
Jack-Chingtse, C
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A midcourse guidance and navigation system for continuous low thrust vehicles was developed. The equinoctial elements are the state variables. Uncertainties are modelled statistically by random vector and stochastic processes. The motion of the vehicle and the measurements are described by nonlinear stochastic differential and difference equations respectively. A minimum time trajectory is defined; equations of motion and measurements are linearized about this trajectory. An exponential cost...
Topics: CLEAR AIR TURBULENCE, JET STREAMS (METEOROLOGY), S WAVES, NONLINEARITY, TROPOPAUSE, TURBULENT...
206
206
Jun 1, 2011
06/11
by
Edquist, Karl T.; Alter, Stephen J
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The proposed Mars Science Laboratory (MSL) mission is intended to deliver a large rover to the Martian surface within 10 km of the target site. This paper presents computational fluid dynamics (CFD) predictions of forebody heating rates for two MSL entry configurations with fixed aerodynamic trim tabs. Results are compared to heating on a 70-deg sphere-cone reference geometry. All three heatshield geometries are designed to trim hypersonically at a 16 deg angle of attack in order to generate...
Topics: ANTARCTIC REGIONS, STRATOSPHERE, WINTER, STRATOSPHERIC WARMING, OZONE DEPLETION, CLIMATE, JET...
712
712
Jun 21, 2010
06/10
by
NON
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Research and development in high temperature test facility
Topics: CLIMBING FLIGHT, DYNAMIC CHARACTERISTICS, FLIGHT PATHS, JET AIRCRAFT, SOARING, AIRSPEED, JET...
310
310
Jun 11, 2011
06/11
by
Gehrels, N.; Cominsky, L. R., et al; Chincarini, G.; Giommi, P.; Mason, K. O.; Nousek, J. A.; Wells, A. A.; White, N. E.; Barthelmy, S. D.; Burrows, D. N.
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The Swift mission: scheduled for launch in early 2004: is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is the first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts per year and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to...
Topics: FLOODS, FLUX DENSITY, JET STREAMS (METEOROLOGY), SOIL MOISTURE, MATHEMATICAL MODELS, EARTH SURFACE,...
A hygrometer for water vapor measurements from an aircraft has been developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on NASA and USAF aircraft. Water vapor measurements were conducted up to 40,000 feet with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of...
Topics: NASA Technical Reports Server (NTRS), AIRBORNE EQUIPMENT, ALUMINUM OXIDES, HYGROMETERS, WATER...
Extratropical eddy distributions in four months typical of the four seasons are treated in terms of temporal mean and temporal r.m.s. values of the geostrophic relative vorticity. The geographical distributions of these parameters at the 300 mb level show that the arithmetic mean fields are highly biased representatives of the extratropical eddy distributions. The zonal arithmetic means of these parameters are also presented. These show that the zonal-and-time mean relative vorticity is but a...
Topics: NASA Technical Reports Server (NTRS), ANNUAL VARIATIONS, JET STREAMS (METEOROLOGY), TROPICAL...
This suite of IDL programs provides identification and comprehensive characterization of the dynamical features of the jet streams in the upper troposphere, the lower stratospheric polar night jet, and the tropopause. The output of this software not only provides comprehensive information on the jets and tropopause, but also gives this information in a form that facilitates studies of observations in relation to the jets and tropopauses.
Topics: NASA Technical Reports Server (NTRS), TROPOPAUSE, JET STREAMS (METEOROLOGY), SCIENTIFIC...
The recent paper in Weather by Young (2014) provided a detailed analysis of an intensive cold front as it passed over the UK on 2223 November 2013. This was an extremely good example of linear convection, as it is described in the paper, or a narrow cold-frontal rainband (NCFR; Hobbs and Biswas, 1979). These features are associated with a low-level jet that lies ahead and parallel to the surface cold front, generating a band of intense but relatively shallow convection (see Koch and Kocin,...
Topics: NASA Technical Reports Server (NTRS), FRONTS (METEOROLOGY), JET STREAMS (METEOROLOGY), RADAR...
247
247
Jun 21, 2010
06/10
by
Rogallo, V. L
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Null-type vacuum microbalance for measuring minute mechanical displacements
Topics: AERODYNAMIC CONFIGURATIONS, WIND TUNNEL MODELS, JET STREAMS (METEOROLOGY), LIFT FANS, VERTICAL...
260
260
May 31, 2011
05/11
by
Jedrich, Nicholas; Zimbelman, Darell; Swift, Walter; Dolan, Franci
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This paper presents a description of the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) Cryo Cooler (NCC), the cutting edge technology involved, its evolution, performance, and future space applications. The NCC is the primary hardware component of the NICMOS Cooling System comprised of the NCC, an Electronics Support Module, a Capillary Pumped Loop/Radiator, and associated interface harnessing. The system will be installed during extravehicular...
Topics: JET STREAMS (METEOROLOGY), MONSOONS, PARAMETERIZATION, POSITIVE FEEDBACK, WATER VAPOR, ATMOSPHERIC...
A relationship is established between relative geostrophic vorticity on an isobaric surface and the Laplacian of the underlying layer-mean temperature. This relationship is used to investigate the distribution of vorticity and baroclinicity in a jet-stream model which is constantly recurrent in the winter troposhere. The investigation shows that the baroclinic and vorticity fields of the extratropical troposphere must be bifurcated with two extrema in the middle and subpolar latitudes. This...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC TEMPERATURE, JET STREAMS (METEOROLOGY), SYNOPTIC...
408
408
May 23, 2011
05/11
by
Freeman, Delma C., Jr.; Talay, Theodore A.; Austin, R. Eugen
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Industry/NASA Reusable Launch Vehicle (RLV) Technology Program efforts are underway to design, test, and develop technologies and concepts for viable commercial launch systems that also satisfy national needs at acceptable recurring costs. Significant progress has been made in understanding the technical challenges of fully reusable launch systems and the accompanying management and operational approaches for achieving a low-cost program. This paper reviews the current status of the Reusable...
Topics: AEROSOLS, OZONE, SULFUR, TROPOPAUSE, TROPOSPHERE, JET STREAMS (METEOROLOGY), STRATOSPHERE, CIRRUS...
Two cases of low-level jet (LLJ) support the hypothesis that the LLJ is an integral part of synoptic-scale cyclogenesis. The appearance of an arch with a row of cumulonimbus is discovered at the front of the LLJ. The inertia oscillations in the LLJ are pointed out as part of the quasi-diurnal variation. A plan for further research by numerical modelling is proposed, which will bring more clarification of the mechanics of the LLJ.
Topics: NASA Technical Reports Server (NTRS), CUMULONIMBUS CLOUDS, CYCLOGENESIS, JET STREAMS (METEOROLOGY),...
Although the albedo of specific belts and zones varies as a function of time, there is evidence that wind maxima may be fixed in latitude. Before considering a standard notation for wind jets, it is necessary to establish a coordinate system within which the nomenclature would be defined. Traditionally, the BAA has used planetographic latitudes; however, this system is based not only on an accurate determination of the polar diameter but also on the assumption that the equipotential surfaces...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, JET STREAMS (METEOROLOGY),...
Four registered channels (0.2 to 4, 6.5 to 7, 10 to 11, and 20 to 23 microns) of the Nimbus 3 Medium Resolution Infrared Radiometer (MRIR) were used to study 24-hr changes in the structure of an extratropical cyclone during a 6-day period in May 1969. Use of a stereographic-horizon map projection insured that the storm was mapped with a single perspective throughout the series and allowed the convenient preparation of 24-hr difference maps of the infrared radiation fields. Single-channel and...
Topics: NASA Technical Reports Server (NTRS), CYCLONES, INFRARED SCANNERS, NIMBUS 3 SATELLITE, TROPICAL...
A mechanism of internal gravity wave generation by jet streams in the troposphere is considered. Evaluations of the energy and pulse of internal gravity waves emitted into the upper atmosphere are given. The obtained values of flows can influence the thermal and dynamic regime of these layers.
Topics: NASA Technical Reports Server (NTRS), GRAVITY WAVES, JET STREAMS (METEOROLOGY), TROPOSPHERE, UPPER...
The Eastern Pacific has the highest frequency of genesis events per unit area of any region worldwide (Elsberry et al 1987). African easterly waves, mesoscale convective systems (MCSs), and topographic effects are thought to play roles in the genesis of tropical cyclones there (Frank and Clark 1980, Velasco and Fritsch 1987, Zehnder 1991, Zehnder and Gall 1991; Farfan and Zehnder 1997). Mozer and Zehnder (1996), using dry, idealized simulations of flow past a large-scale three-dimensional...
Topics: NASA Technical Reports Server (NTRS), TROPICAL STORMS, HURRICANES, MESOSCALE PHENOMENA, JET STREAMS...
227
227
May 29, 2011
05/11
by
Wyss, R. A.; Karasik, B. S.; McGrath, W. R.; Bumble, B.; LeDuc, H
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Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 micrometer in a quasioptical mixer configuration employing twin-slot antennas. The 3-dB EF bandwidth increased from 1.2 GHz for the 0.3 gm long...
Topics: AMAZON REGION (SOUTH AMERICA), BALLOON SOUNDING, TROPICAL REGIONS, DROUGHT, EL NINO, JET STREAMS...
The real-time treatment of interactive realistically varying aerosol in a global operational forecasting system, as opposed to prescribed (fixed or climatologically varying) aerosols, is a very difficult challenge that only recently begins to be addressed. Experiment results from a recent version of the NASA GEOS-5 forecasting system, inclusive of interactive aerosol treatment, are presented in this work. Four sets of 30 5-day forecasts are initialized from a high quality set of analyses...
Topics: NASA Technical Reports Server (NTRS), AEROSOLS, AFRICA, MONSOONS, WEATHER FORECASTING, DUST, JET...
The subsynoptis-scale kinetic energy balance during the Red River Valley tornado outbreak is presented in order to diagnose storm environment interactions. Area-time averaged energetics indicate that horizontal flux convergence provides the major energy source to the region, while cross contour flow provides the greatest sink. Maximum energy variability is found in the upper levels in association with jet stream activity. Area averaged energetics at individual observation times show that the...
Topics: NASA Technical Reports Server (NTRS), CONVECTION, ENERGY TRANSFER, JET STREAMS (METEOROLOGY),...
Total ozone and NO2 were measured aboard a ship in the 40S - 40N latitude band in the Atlantic Ocean in the second half of May 1988. The main features of the latitudinal distributions of total NO2 and ozone are similar. There is seen an increase of total ozone and NO2 from the tropical to subtropical latitudes, strongest in the region of the subtropical jet stream. The fine structure has been revealed in the total ozone and NO2 latitudinal distributions, connected most likely with...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, ATMOSPHERIC COMPOSITION, LATITUDE,...
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.
Topics: NASA Technical Reports Server (NTRS), CLIMATOLOGY, JET STREAMS (METEOROLOGY), MIDDLE ATMOSPHERE,...
The AVE 4 Experiment is described and tabulated rawinsonde data at 25-mb intervals from the surface to 25 mb for the 42 stations participating in the experiment are presented. Soundings were taken between 0000 GMT, April 24 and 1200 GMT, April 25, 1975. The methods of data processing and accuracy are discussed. Synoptic charts prepared from the data are presented, as well as an example of contact data.
Topics: NASA Technical Reports Server (NTRS), METEOROLOGICAL CHARTS, RAWINSONDES, SYNOPTIC METEOROLOGY,...
A quasi-geostrophic numerical model, including friction, radiation, and the observed planetary topography, is applied to the general circulation of the Martian atmosphere in the Southern Hemisphere at latitudes south of about 35 deg. Near equilibrium weather systems developed after about 5 model days. To avoid violating the quasi-geostrophic approximation, only 0.8 of the already smoothed relief was employed. Weather systems and velocity fields are strikingly tied to topography. A 2mb middle...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, MARS ATMOSPHERE, MATHEMATICAL...
Two fundamentally different views of the general circulation of Jovian atmospheres have emerged. According to one view, the observed jet streams at the cloud tops are controlled by the vorticity transfers of small scale eddies generated by planetary wave instabilities within a shallow atmospheric layer. According to the alternate point of view, the zonal jets are surface manifestations of deep interior convection organized into cylindrical motion with axes parallel to the planetary rotation...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, EDDY VISCOSITY, GEOSTROPHIC WIND,...
The formation of a blocking anticyclone over the North Atlantic has been examined over its entire life-CyCle using the Zwack-Okossi (Z-O) equation as the diagnostic tool. This blocking anticyclone occurred in late October and early November of 1985. The data used were provided by the NASA Goddard Laboratory for Atmospheres on a global 2.O degree latitude by 2.5 degree longitudinal grid. The horizontal distribution of the atmospheric forcing mechanisms that were important to 500 mb block...
Topics: NASA Technical Reports Server (NTRS), ANTICYCLONES, ATLANTIC OCEAN, TROPOSPHERE, SYNOPTIC...
Surface and upper-level characteristics of selected meteorological fields are summarized. Two major types of sea level development are described and applied to the cases at hand, with a few storm systems showing characteristics of both types. Aspects such as rapid sea level deepening, coastal frontogenesis, cold air damming, low level jet formation, the development of an S-shaped isotherm pattern, diffluence downwind of a negatively tilted upper level trough axis, upper level confluence and an...
Topics: NASA Technical Reports Server (NTRS), CYCLOGENESIS, FRONTS (METEOROLOGY), ISOTHERMS, SNOW,...
Preliminary results of themomentum flux and flux divergence during a transient episode, as a jet stream moved over the radar are given. The zonal and meridional momentum flux and flux divergences displayed remarkable continuity with altitude in time, increasing in intensity as lee waves and other gravity-wave activity developed while the jet stream approached. The momentum flux values observed compare favorably with aircraft measurements made over similar topography, at least during the early...
Topics: NASA Technical Reports Server (NTRS), GRAVITY WAVES, JET STREAMS (METEOROLOGY), METEOROLOGICAL...
The simulations of climatology and response of the South American summer monsoon (SASM) to the 1997/98 El Nino are investigated using six atmospheric general circulation models. Results show all models simulate the large-scale features of the SASM reasonably well. However, both stationary and seasonal components of the surface pressure are overestimated, resulting in an excessively strong SASM in the model climatology. The low-level northwesterly jet over eastern foothills of the Andes is not...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC GENERAL CIRCULATION MODELS, CLIMATOLOGY, EL NINO,...
During the past several years, research on the structure of extra-tropical jet streams has been carried out with direct measurements with instrumented research aircraft from the National Center for Atmospheric Research (NCAR). These measurements have been used to describe the wind, temperature, turbulence and chemical characteristics of jet streams. A fundamental question is one of assessing the potential value of existing operational numerical forecast models for forecasting the meteorological...
Topics: NASA Technical Reports Server (NTRS), JET STREAMS (METEOROLOGY), METEOROLOGICAL RESEARCH AIRCRAFT,...
Present and future utilization of satellite weather data by commercial aircraft while in flight was assessed. Weather information of interest to aviation that is available or will become available with future geostationary satellites includes the following: severe weather areas, jet stream location, weather observation at destination airport, fog areas, and vertical temperature profiles. Utilization of this information by in-flight aircraft is especially beneficial for flights over the oceans...
Topics: NASA Technical Reports Server (NTRS), IN-FLIGHT MONITORING, METEOROLOGICAL SATELLITES,...
Studies of ageostrophic motion attending jet streaks and convection are examined. Various types of dynamical experiments are carried out with the hybrid isentropic-sigma coordinate model. The effects of vorticity and static stability distributions on the intensity of secondary circulations forced by inertial accelerations as well as the superposition of an amplifying baroclinic wave on the jet streak structure are investigated.
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MODELS, BAROCLINIC INSTABILITY, GEOSTROPHIC WIND,...
Six years of twice daily global analyses were used to create and study a lengthy time series of high temporal resolution angular momentum values. Changes in these atmospheric values were compared to independently determined charges in the rotation rate of the solid Earth. Finally, the atmospheric data was examined in more detail to determine the time and space scales on which variations in momentum occur within the atmosphere and which regions are contributing most to the changes found in the...
Topics: NASA Technical Reports Server (NTRS), ANGULAR MOMENTUM, ATMOSPHERIC CIRCULATION, DAYTIME, EARTH...
Atmospheric structure derived from satellite, multichannel radiance data is used to calculate zonally averaged vertical motions in the wintertime stratosphere of both hemispheres using a heat budget approach. The Northern Hemisphere calculations based on the satellite data are shown to compare favorably with a computation carried out with conventional data, and with results of previous studies. The mean Southern Hemisphere pattern for the month of July 1969 indicates a two-celled structure with...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, NORTHERN HEMISPHERE, SATELLITE...
A review of 15 cases of low level jets (LLJ) which developed in the Great Plains is presented. For 12 out of the 15 cases, a systematic upper level flow pattern was isolated which includes the existence of a trough over the southwest United States and the propagation of upper level jet streaks from the Rocky Mountains toward the Great Plains. This flow pattern is responsible for lee side cyclogenesis or lee side troughing that produces the pressure gradients needed for the development of the...
Topics: NASA Technical Reports Server (NTRS), CYCLOGENESIS, JET STREAMS (METEOROLOGY), TROPOSPHERE,...
Recently, Sassen provided evidence for supercooled water droplets in cirrus uncinus cell heads at temperatures between 40 and -50 C. Chemistry related to volcanic aerosol of stratospheric origin was evoked as an explanation for this phenomenon. Sassen speculated that injections of sulfuric acid droplets into the upper troposphere were accomplished by tropopause folds associated with subtropical jet streams. He also postulated global climatic perturbations due to the effect of these cirrus...
Topics: NASA Technical Reports Server (NTRS), AEROSOLS, CIRRUS CLOUDS, JET STREAMS (METEOROLOGY), SULFURIC...
Despite the fact that the low-level jet of the southern Great Plains (the GPLLJ) of the U.S. is primarily a nocturnal phenomenon that virtually vanishes during the daylight hours, it is one of the most persistent and stable features of the low-level continental flow during the warm-season months, May through August. We have first used significant-level data to validate the skill of the GEOS-1 Data Assimilation System (DAS) in realistically detecting this jet and inferring its structure and...
Topics: NASA Technical Reports Server (NTRS), JET STREAMS (METEOROLOGY), MERIDIONAL FLOW, ANNUAL...
The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place...
Topics: NASA Technical Reports Server (NTRS), ANTARCTIC REGIONS, WINTER, STRATOSPHERIC WARMING, OZONE...
Several research projects were worked on between August 1990 and May 1991. Topics covered included observational and modeling studies of relationships between tropical heat sources and subtropical jet streams, the intraseasonal (30 to 60 day) oscillation near the equator, and precipitation over tropical oceans. Current research activities and plans for the coming year are outlined.
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, HEAT FLUX, HEAT SOURCES, JET STREAMS...
The feasibility of detecting a thin cirrus and clear air turbulence from ERTS MSS data is explored. The result of analyses indicates that a thin cirrus not shown in conventional meteorological satellite picture can be revealed in ERTS MSS picture. It is also found that the core of jet stream can be located with high accuracy from ERTS pictures and the possible area of clear air turbulence can be predicted if the data of the quality of ERTS data are available in real time.
Topics: NASA Technical Reports Server (NTRS), CIRRUS CLOUDS, CLEAR AIR TURBULENCE, JET STREAMS...
The global climatology and understanding of stratospheric aerosols evolving primarily from lidar and satellite measurements is presented. The importance of validation of these remotely sensed data with in situ measurements is also discussed. The advantage of lidar for providing high vertical and horizontal resolution and its independence from a remote source for measurement will become evident with examples of long term lidar data sets at fixed sites and the use of lidar on airborne platforms....
Topics: NASA Technical Reports Server (NTRS), AEROSOLS, ATMOSPHERIC CIRCULATION, OPTICAL RADAR,...
Examples of convection in rotating layers are presented to illustrate how convection can drive global circulations on the Jovian planets. For rapid rotation the convective motions become largely two-dimensional and produce Reynold stresses which drive large scale flows. The initial tendency is to produce a prograde equatorial jet and a meridional circulation which is directed toward the poles in the surface layers. Fully nonlinear numerical simulations for the slowly rotating solar convection...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, CONVECTIVE FLOW, JET STREAMS...
Results from a test to determine the effectiveness of satellite data for helping airlines avoid heavy concentrations of ozone are reported. Information from the Total Ozone Mapping Spectrometer, aboard the Nimbus-7 was transmitted, for use in meteorological forecast activities. The results show: (1) Total Ozone Mapping Spectrometer profile of total ozone in the atmosphere accurately represents upper air patterns and can be used to locate meteorological activity; (2) route forecasting of highly...
Topics: NASA Technical Reports Server (NTRS), AIRLINE OPERATIONS, FLIGHT PLANS, OZONE, OZONOMETRY,...
The internship of the author is examined in detail. The acquisition of the internship, the personnel of the project, the project itself, and the goals associated with it are described. The authors orientation to the internship, the project's operations, and the conclusion of the findings are also described. The overall goal of the project was to determine the effect of convective waves on wind speeds in the middle and upper troposphere, and how these waves affect the general circulation on a...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC BOUNDARY LAYER, ATMOSPHERIC CIRCULATION,...
We have utilized an extensive set of independent British Airways flight data recording wind vector and temperature observations (the Global Aircraft Data Set [GADS] archive) in three ways: (a) as an independent check of operational analyses; (b) as an analysis observing system experiment (OSE) as if the GADS observations were available in real time; and (c) as the corresponding forecast simulation experiment applicable to future operational forecasts. Using a 31 day sample (0000 UTC 20 December...
Topics: NASA Technical Reports Server (NTRS), JET STREAMS (METEOROLOGY), ERRORS, WIND VELOCITY, WEATHER...
Blackwell et al. successfully simulated tropical plumes in a global barotropic model valid at 200 mb. The plume evolved in response to strong equatorial convergence which simulated a surge in the Walker Circulation. The defining characteristics of simulated plumes are: a subtropical jet with southerlies emanating from the deep tropics; a tropical/mid-latitude trough to the west; a convergence/divergence dipole straddling the trough; and strong cross contour flow at the tropical base of the jet....
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, ATMOSPHERIC MODELS, DIVERGENCE, JET...
This research grant was a revised version of an original proposal. The period of the grant was for three years with a six-month no-cost extension; thus, it was from 20 July 1990 to 19 January 1994. The objectives of the grant were to identify periods and locations of active convection centers, primarily over the Southern Hemisphere tropical Indian and Pacific Oceans; determine reasons for any periodic behavior found in the first objective; identify cases where subtropical jets over the South...
Topics: NASA Technical Reports Server (NTRS), AIR WATER INTERACTIONS, ATMOSPHERIC CIRCULATION, ATMOSPHERIC...
Interaction between the mass circulation within a mesoscale convective complex (MCC) and a direct mass circulation in the entrance region of an upper tropospheric polar jet streak was examined within the isentropic structure to investigate mechanisms responsible for linking these two scales of motion. The results establish that latent heating in the MCC modifies the direct mass circulation in the jet streak entrance region through the diabatically induced components of ageostrophic motion...
Topics: NASA Technical Reports Server (NTRS), ADIABATIC CONDITIONS, ATMOSPHERIC CIRCULATION, GEOSTROPHIC...
Initial conditions are designed for numerical simulation of mesocale processes in the atmosphere using the Limited Area Mesoscale Prediction System (LAMPS) model. These initial conditions represent an idealized baroclinic wave in which the transport of water vapor can be simulated. The constructed atmosphere has two homogeneous air masses, polar front, polar jet stream and a stratosphere. All these simulate the basic structure of the earth's atmosphere. The hydrostatic and geostrophic balances...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, MATHEMATICAL MODELS, MESOSCALE...
It is well known that prograde equatorial jet stresses cannot occur in an axisymmetric inviscid fluid, owing to the constraints of local angular momentum conservation. For a viscous fluid, the constraints of mass conservation prevent the formation of any local maximum of absolute angular momentum (m) without a means of transferring m against its gradient (delta m) in the meridional plane. The circumstances under which m can be diffused up-gradient by normal molecular viscosity are derived, and...
Topics: NASA Technical Reports Server (NTRS), ANGULAR MOMENTUM, EDDY VISCOSITY, EQUATORIAL ATMOSPHERE, JET...
