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124 records · Page 7

Transverse ageostrophic circulations associated with elevated mixed layers

The nature of the frontogenetically forced transverse ageostrophic circulations connected with elevated mixed layer structure is investigated as a first step toward diagnosing the complex vertical circulation patterns occurring in the vicinity of elevated mixed layers within a severe storm environment. The Sawyer-Eliassen ageostrophic circulation equation is reviewed and applied to the elevated mixed layer detected in the SESAME IV data set at 2100 GMT of May 9, 1979. The results of the ageostrophic circulation diagnosis are confirmed and refined by considering an analytic specification for the elevated mixed layer structure.

Keyser, D.↗

A case study of the effects of random errors in rawinsonde data on computations of ageostrophic winds

Data input for the AVE-SESAME I experiment are utilized to describe the effects of random errors in rawinsonde data on the computation of ageostrophic winds. Computer-generated random errors for wind direction and speed and temperature are introduced into the station soundings at 25 mb intervals from which isentropic data sets are created. Except for the isallobaric and the local wind tendency, all winds are computed for Apr. 10, 1979 at 2000 GMT. Divergence fields reveal that the isallobaric and inertial-geostrophic-advective divergences are less affected by rawinsonde random errors than the divergence of the local wind tendency or inertial-advective winds.

Moore, J. T.↗

Results from a limited area mesoscale numerical simulation for 10 April 1979

Results are presented from a nine-hour limited area fine mesh (35-km) mesoscale model simulation initialized with SESAME-AVE I radiosonde data for Apr. 10, 1979 at 2100 GMT. Emphasis is on the diagnosis of mesoscale structure in the mass and precipitation fields. Along the Texas/Oklahoma border, independent of the short wave, convective precipitation formed several hours into the simulation and was organized into a narrow band suggestive of the observed April 10 squall line.

Kalb, M. W.↗

A diagnostic approach to obtaining planetary boundary layer winds using satellite-derived thermal data

The feasibility of using satellite derived thermal data to generate realistic synoptic scale winds within the planetary boundary layer (PBL) is examined. Diagnostic modified Ekman wind equations from the Air Force Global Weather Central (AFGWC) Boundary Layer Model are used to compute winds at seven levels within the PBL transition layer (50 m to 1600 m AGL). Satellite derived winds based on 62 predawn TIROS-N soundings are compared to similarly derived wind fields based on 39 AVE-SESAME II rawinsonde (RAOB) soundings taken 2 h later. Actual wind fields are also used as a basis for comparison. Qualitative and statistical comparisons show that the Ekman winds from both sources are in very close agreement, with an average vector correlation coefficient of 0.815. Best results are obtained at 300 m AGL. Satellite winds tend to be slightly weaker than their RAOB counterparts and exhibit a greater degree of cross-isobaric flow. The modified Ekman winds show a significant improvement over geostrophic values at levels nearest the surface.

Belt, Carol L.↗

Application of satellite data to the variational analysis of the three dimensional wind field

The use of a hybrid vertical velocity algorithm, composed of the kinematic and adiabatic methods of Pettersen (1956), to analyze three-dimensional wind fields is studied. The basic principles and advantages and disadvantages of the adiabatic and kinematic techniques are discussed. The adiabatic method is useful in the clear regions and above the tropopause and the kinematic method is applicable near the surface and in cloudy regions. The effects of a finite difference scheme and the objective analysis of Barnes (1973) on a wind field are investigated. The variational algorithm is evaluated by applying it to SESAME data collected in April 1979.

Chance, Barbara A.↗

Calculation of geopotential and temperature fields from an array of nearly continuous wind observations

The accuracy is studied of temperature estimates derived from the divergence equation when wind observations of various spatial and temporal resolutions and accuracies are available. The basic data set used is the high resolution model data set used by Kuo and Anthes (1984a) in observing systems simulation experiments (OSSE) designed to estimate the errors in heat and moisture budgets (Kuo and Anthes, 1984b) calculated from the AVE-SESAME-1979 spatial observational network. This model data set is modified in ways to simulate wind observations that appear feasible from an operational regional network of wind profilers.

Kuo, Ying-Hwa↗

Grand challenge scientific questions in coupled modeling

Most convective field experiments in the past (e.g., SESAME, CCOPE, CINDE) have attempted to resolve only the immediate scales of moist convection using network arrays that spanned two or three atmospheric scales at most. Furthermore, these scales have been defined more on practical considerations (cost, manpower, etc.) than on a clear understanding of their theoretical significance. Unfortunately, this has precluded a description of the entire life cycle of MCS's and their interaction with larger scale systems, the land surface, and trace species. Fortunately, the following factors now make it possible to attempt to simulate scale contraction processes from the synoptic scale down to the cloud scale, as well as interactions between complex meteorological, land surface, precipitation, chemical, and hydrologic processes with coupled, multiscale models: the availability of new technology to sample meteorological fields at high temporal and spatial resolution over a broad region made possible by the weather observing modernization program; increased computer power and improved numerical approaches to run limited area models with nonhydrostatic precipitation physics so as to explicitly resolve MCS (Mesoscale Convective System) processes; and four dimensional assimilation of non-conventional data to provide dynamically consistent datasets for diagnostic analysis of nonlinear scale-interactive dynamics. Several examples of scale-interactive processes which present grand challenges for coupled, multiscale modeling were presented.

Koch, Steven↗

Science Planning for the TROPIX Mission

The objective of the study grant was to undertake the planning needed to execute meaningful solar electric propulsion missions in the magnetosphere and beyond. The first mission examined was the Transfer Orbit Plasma Investigation Experiment (TROPIX) mission to spiral outward through the magnetosphere. The next mission examined was to the moon and an asteroid. Entitled Diana, it was proposed to NASA in October 1994. Two similar missions were conceived in 1996 entitled CNR for Comet Nucleus Rendezvous and MBAR for Main Belt Asteroid Rendezvous. The latter mission was again proposed in 1998. All four of these missions were unsuccessfully proposed to the NASA Discovery program. Nevertheless we were partially successful in that the Deep Space 1 (DS1) mission was eventually carried out nearly duplicating our CNR mission. Returning to the magnetosphere we studied and proposed to the Medium Class Explorer (MIDEX) program a MidEx mission called TEMPEST, in 1995. This mission included two solar electric spacecraft that spiraled outward in the magnetosphere: one at near 900 inclination and one in the equatorial plane. This mission was not selected for flight. Next we proposed a single SEP vehicle to carry Energetic Neutral Atom (ENA) imagers and inside observations to complement the IMAGE mission providing needed data to properly interpret the IMAGE data. This mission called SESAME was submitted unsuccessfully in 1997. One proposal was successful. A study grant was awarded to examine a four spacecraft solar electric mission, named Global Magnetospheric Dynamics. This study was completed and a report on this mission is attached but events overtook this design and a separate study team was selected to design a classical chemical mission as a Solar Terrestrial Probe. Competing proposals such as through the MIDEX opportunity were expressly forbidden. A bibliography is attached.

Russell, C. T.↗

Intelligent Agent Technology

Open Sesame! is the first commercial software product that learns user's behavior, and offers automation and coaching suggestions to the user. The neural learning module looks for repetitive patterns that have not been automated; when it finds one, it creates an observation and, upon approval, automates the task. The manufacturer, Charles River Analytics, credits Langley Research Center and Johnson Space Center Small Business Innovation Research grants and the time the president and vice president spent at the two centers in the 1970s as being essential to the development of their product line.

Source record↗

The effects of programmed administration of human parathyroid hormone fragment (1-34) on bone histomorphometry and serum chemistry in rats

PTH treatment can result in dramatic increases in cancellous bone volume in normal and osteopenic rats. However, this potentially beneficial response is only observed after pulsatile treatment; continuous infusion of PTH leads to hypercalcemia and bone abnormalities. The purpose of these studies was to determine the optimal duration of the PTH pulses. A preliminary study revealed that human PTH-(1-34) (hPTH) is cleared from circulation within 6 h after sc administration of an anabolic dose of the hormone (80 microg/kg). To establish the effects of gradually extending the duration of exposure to hPTH without increasing the daily dose, we programmed implanted Alzet osmotic pumps to deliver the 80 microg/kg x day dose of the hormone during pulses of 1, 2, and 6 h/day, or 40 microg/kg x day continuously. Discontinuous infusion was accomplished by alternate spacing of external tubing with hPTH solution and sesame oil. After 6 days of treatment, we evaluated serum chemistry and bone histomorphometry. As negative and positive controls, groups of rats received pumps that delivered vehicle only and 80 microg/kg x day hPTH by daily sc injection, respectively. Dynamic and static bone histomorphometry revealed that the daily sc injection and 1 h/day infusion dramatically increased osteoblast number and bone formation in the proximal tibial metaphysis, whereas longer infusion resulted in systemic side-effects, including up to a 10% loss in body weight, hypercalcemia, and histological changes in the proximal tibia resembling abnormalities observed in patients with chronic primary hyperparathyroidism, including peritrabecular marrow fibrosis and focal bone resorption. Infusion for as little as 2 h/day resulted in minor weight loss and changes in bone histology that were intermediate between sc and continuous administration. The results demonstrate that the therapeutic interval for hPTH exposure is brief, but that programmed administration of implanted hormone is a feasible alternative to daily injection as a route for administration of the hormone.

Non-NASA Center↗

Chlorine Partitioning in the Arctic Vortex During Winter 1995 Derived From Submillimeterwave Remote Sensing and in Situ Constituent Measurements

High altitude balloon flights of a combined payload of the Submillimeterwave Limb Sounder and the whole air sampler instruments were performed on 27 January 1995 and 08 March 1995. Both flights were launched from sweden as part of the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME). Results of the first flight suggest that most of the available chlorine had been converted to CLOx in the observed air parcel, while warmer air in the second flight had much more HCl than CLOx.

Arctic vortex stratosphere chlorine remote sensing↗

NASA Science Technology Development Programs for Ocean Worlds Exploration

The exploration of ocean worlds such as Europa and Enceladus supports NASA’s goal to search for life and potentially habitable regions elsewhere in the universe, and further promises to help us understand the origins, evolution, and limits of life on Earth. Over the past several years, NASA’s Planetary Science Division has funded several technology development programs to enable future surface and subsurface missions to ocean worlds. These programs include Instrument Concepts for Europa Exploration (ICEE), Concepts for Ocean Worlds Life Detection Technology (COLDTech), Scientific Exploration Subsurface Access Mechanism for Europa (SESAME), Applied Information Systems Research: Autonomous Robotics Research for Ocean Worlds (AISR:ARROW), and Astrodynamics in Support of Icy Worlds Missions. Tasks selected under these programs include the development of scientific instruments including seismometers, imagers, spectrometers, and organic analyzers, and platform technologies including drills, melt probes, through-ice communications, radiation-hard electronics, and autonomy for surface operations. This paper describes the objectives of each of these programs and provides a summary of the work that has been completed or is underway in each.

technology↗

NASA Science Technology Development Programs for Ocean Worlds Exploration

The exploration of icy satellites such as Europa and Enceladus supports NASA’s goal to search for life and potentially habitable regions elsewhere in the universe, and further promises to help us understand the origins, evolution, and limits of life on Earth. Over the past several years, NASA’s Planetary Science Division has funded several technology development programs to enable future surface and subsurface missions to ocean worlds. These programs include Instrument Concepts for Europa Exploration (ICEE), Concepts for Ocean Worlds Life Detection Technology (COLDTech), Scientific Exploration Subsurface Access Mechanism for Europa (SESAME), Applied Information Systems Research: Autonomous Robotics Research for Ocean Worlds (AISR:ARROW), and Astrodynamics in Support of Icy Worlds Missions. Tasks selected under these programs include the development of scientific instruments including seismometers, imagers, spectrometers, and organic analyzers, and also platform technologies including drills, melt probes, through-ice communications, radiation-hard electronics, and autonomy for surface operations. This paper describes the objectives of each of these programs and provides a summary of the work that has been completed or is underway in each.

science instruments↗

NASA Science Technology Development Programs for Ocean Worlds Exploration

The exploration of ocean worlds such as Europa and Enceladus supports NASA’s goal to search for life and potentially habitable regions elsewhere in the universe, and further promises to help us understand the origins, evolution, and limits of life on Earth. Over the past several years, NASA’s Planetary Science Division has funded several technology development programs to enable future surface and subsurface missions to ocean worlds. These programs include Instrument Concepts for Europa Exploration (ICEE), Concepts for Ocean Worlds Life Detection Technology (COLDTech), Scientific Exploration Subsurface Access Mechanism for Europa (SESAME), Applied Information Systems Research: Autonomous Robotics Research for Ocean Worlds (AISR:ARROW), and Astrodynamics in Support of Icy Worlds Missions. Tasks selected under these programs include the development of scientific instruments including seismometers, imagers, spectrometers, and organic analyzers, and platform technologies including drills, melt probes, through-ice communications, radiation-hard electronics, and autonomy for surface operations. This paper describes the objectives of each of these programs and provides a summary of the work that has been completed or is underway in each.

Nayar, Hari D↗

New equations of state for saturated tuff based on the CHEST model

The CHemical Equilibrium for Saturated Tuff (CHEST) model was originally presented in Ref. 1, with numerical results depicted in Figure 1 and tabulated in Appendix B of that work. The results consisted of specific internal energy as a function of pressure and specific volume, E(P, V), spanning the domain P = 10 –4 – 10 4 kbar and V = 0.17 – 752 cm 3 /g (ρ = 1.33 × 10 –3 – 5.9 g/cm 3 ).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗