NASA Scientific and Technical Aerospace Reports

20040074206 Arizona Univ., Tucson, AZ, USA
The Abundance and Isotopic Composition of Hg in Extraterrestrial Materials
Lauretta, D. S.; [2004]; 5 pp.; In English
Contract(s)/Grant(s): NAG5-11355; No Copyright; Avail: CASI; A01, Hardcopy
During the past three year grant period we made excellent progress in our study of the abundances and isotopic
compositions of Hg and other volatile trace elements in extraterrestrial materials. As part of my startup package I received
funds to construct a state-of-the-art experimental facility to study gas-solid reaction kinetics. Much of our effort was spent
developing the methodology to measure the abundance and isotopic composition of Hg at ultratrace levels in solid materials.
In our first study, the abundance and isotopic composition of Hg was determined in bulk samples of the Murchison (CM) and
Allende (CV) carbonaceous chondrites. We have continued our study of mercury in primitive meteorites and expanded the
suite of meteorites to include other members of the CM and CV chondrite group as well as CI and CO chondrites. Samples
of the CI chondrite Orgueil, the CM chondrites Murray, Nogoya, and Cold Bokkeveld, the CO chondrites Kainsaz, Omans,
and Isna, and the CV chondrites Vigarano, Mokoia, and Grosnaja were tested. We have developed a thermal analysis ICP-MS
technique and applied it to the study of a suite of thermally labile elements (Zn, As, Se, Cd, In, Sn, Sb, Te, Hg, Au, Tl, Pb,
and Bi) in geologic materials as well.
Derived from text
Mercury (Metal); Meteoritic Composition; Abundance; Isotope Ratios
20040074237 NASA Goddard Space Flight Center, Greenbelt, MD, USA
Feasibility of Sensing Tropospheric Ozone with MODIS 9.6 Micron Observations
Prabhakara, C.; Iacovazzi, R., Jr.; Moon-Yoo, Jung; [2004]; 2 pp.; In English; AGU Fall 2003 Meeting, 8-12 Dec. 2003, San
Francisco, CA, USA; No Copyright; Avail: Other Sources; Abstract Only
With the infrared observations made by the Moderate Resolution Imaging Spectrometer (MODIS) on board the
EOS-Aqua satellite, which include the 9.73 micron channel, a method is developed to deduce horizontal patterns of
tropospheric ozone in cloud free conditions on a scale of about 100 km. It is assumed that on such small scale, at a given
instant, horizontal changes in stratospheric ozone are small compared to that in the troposphere. From theoretical simulations
it is found that uncertainties in the land surface emissivity and the vertical thermal stratification in the troposphere can lead
to significant errors in the inferred tropospheric ozone. Because of this reason in order to derive horizontal patterns of
tropospheric ozone in a given geographic area a tuning of this method is necessary with the help of a few dependent cases.
After tuning, this method is applied to independent cases of MODIS data taken over Los Angeles basin in cloud free conditions
to derive horizontal distribution of ozone in the troposphere. Preliminary results indicate that the derived patterns of ozone
resemble crudely the patterns of surface ozone reported by EPA.
Author
MODIS (Radiometry); Ozone; Troposphere; Earth Surface; Satellite Observation; Detection
92
SOLAR PHYSICS
Includes solar activity, solar flares, solar radiation and sunspots. For related information see 93 Space Radiation.
20040068144 Stanford Univ., CA, USA
Simulation of Multiple Shocks in the Solar Atmosphere using a High-Order Shock-Capturing Scheme
Bryson, Steve; Kosovichev, A.; Levy, Doron; January 2004; 1 pp.; In English; SIAM 2004 Annual Meeting, 12 - 16 Jul. 2004,
Portland, OR, USA; No Copyright; Avail: Other Sources; Abstract Only
We present a simulation of shock phenomena in the solar atmosphere using high-order shock capturing central-upwind
schemes, based on the Euler equation in gravity. These simulations use observation-based initial conditions, with results
matching observation. Various difficulties are highlighted, including very high gradients in the initial data, multiple scales, and
initialization in hydrostatic equilibrium. We focus on the design of algorithms to address these problems, as well as the
interaction with observational data.
Author
Solar Atmosphere; Computerized Simulation; Shock Waves; Upwind Schemes (Mathematics)
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