A5091647418- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Spaceflight effects on biology
- Space Science and Extraterrestrial Life
- Atmospheric and Environmental Gas Dynamics
- Scientific Research and Discoveries
- Space exploration and regulation
- Geology and Paleoclimatology Research
- Solar and Space Plasma Dynamics
- Gas Dynamics and Kinetic Theory
- Ionosphere and magnetosphere dynamics
- Aeolian processes and effects
- Light effects on plants
- Atmospheric aerosols and clouds
- Spacecraft and Cryogenic Technologies
- Methane Hydrates and Related Phenomena
- Tropical and Extratropical Cyclones Research
- Meteorological Phenomena and Simulations
- Spacecraft Design and Technology
- Radiative Heat Transfer Studies
- Climate change and permafrost
- Nuclear Issues and Defense
- Statistical and numerical algorithms
- Geophysics and Sensor Technology
Ames Research Center
2012-2022
Planetary Systems (United States)
2022
San Jose State University
1996-2007
University of Alaska Fairbanks
2003
Search for Extraterrestrial Intelligence
2000
University of Reading
2000
University Foundation
2000
Stanford University
2000
George Washington University
1998
University of Arizona
1998
The Mars Global Surveyor (MGS) z -axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared only three previous such structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large response at mid-northern latitudes, increasing altitude pressure surfaces there by as much 8 kilometers indicating strong global storm. Throughout MGS mission, density...
The NASA Ames Mars General Circulation Model is used to interpret selected results from the Pathfinder atmospheric structure instrument/meteorology (ASI/MET) experiment. present version of model has an improved soil thermal model, a new boundary layer scheme, and correction for non‐local thermodynamic equilibrium effects at solar wavelengths. We find good agreement with ASI/MET entry data if dust observed site assumed be distributed throughout lowest five six scale heights. This implies that...
Abstract We provide a preliminary interpretation of the Rover Environmental Monitoring Station (REMS) pressure data from first 100 Martian solar days (sols) Mars Science Laboratory mission. The sensor is performing well and has revealed existence phenomena undetected by previous missions that include possible gravity waves excited evening downslope flows, relatively dust‐free convective vortices analogous in structure to dust devils, signatures indicative circulation induced Gale Crater its...
We examined the effects of summer warmth on leaf area index (LAI), total aboveground phytomass (TAP), and normalized difference vegetation (NDVI) across Arctic bioclimate zone in Alaska extrapolated our results to circumpolar Arctic. Phytomass, LAI, within homogeneous areas acidic nonacidic soils were regressed against (SWI) at 12 climate stations northern (SWI = sum mean monthly temperatures greater than 0°C). SWI varies from 9°C Barrow 37°C Happy Valley. A 5°C increase is correlated with...
We describe and document the physics packages in legacy NASA/Ames Mars Global Climate Model, present simulations of seasonal water cycle how it compares with observations, assess role radiatively active clouds on planetary eddies, discuss strengths weakness model implication for future efforts. The we include treatment surface properties, ground temperature model, boundary layer scheme, sublimation physics, cloud microphysics, use a moment method tracer transport, semi-interactive dust...
The vertical propagation of nonmigrating (i.e., longitude‐dependent or non–Sun‐synchronous) solar diurnal and semidiurnal tides into the thermosphere Mars is investigated through numerical simulation. waves are generated in NASA Ames general circulation model (MGCM) radiative, topographic, nonlinear processes using a comprehensive physics package including cycle. At an altitude near 70 km, zonal wave number decompositions tidal fields performed, each component extended from to 250 km linear...
Mariner 9 and Viking spacecraft observations provided evidence for planetary-scale, wavelike disturbances in the Mars winter atmosphere. Possible sources of wave activity are dynamical instabilities, example, barotropic / or baroclinic instabilities. Other candidate forced. quasi-stationary planetary waves—waves that arise predominantly via zonally asymmetric surface properties. The authors attempt to model aspects activity, focusing on forced waves representative wintertime atmospheres...
Mars Global Surveyor performed a series of radio occultation experiments in December 1998, resulting 36 profiles the neutral atmosphere late northern spring ( L s = 74.1°–77.3°). The measurements are confined latitude (64.6°–67.2°N) and local time (0321–0418), but their distribution longitude is fairly uniform. We used least squares spectral analysis to characterize zonal structure constructed longitude‐height cross sections both temperature geopotential. Zonal variations exceed 12 K near...
A 3D global circulation model is adapted to the atmosphere of Venus explore nature planet's atmospheric superrotation. The employs full meteorological primitive equations and simplified forms for diabatic other nonconservative forcings. It therefore economical performing very long simulations. To assess equilibration occurrence superrotation, climate run 10,000–20,000 day integrations at 4° × 5° latitude‐longitude horizontal resolution, 56 vertical levels (denoted L56). sensitivity these...
A Mars GCM is utilized to investigate dust lifting and organization associated with extratropical cyclogenesis frontal waves. The model applied at high resolution in simulations related Mars' cycle. single synoptic weather event examined ascertain lifting, transport convergence/divergence of by large‐scale cyclonic/anticyclonic systems, the sub‐synoptic waves that ensue. Low‐ high‐pressure cores develop, travel eastward remain mostly confined within seasonal CO 2 polar cap. bulk occurs...
We present a study that is motivated by population of water ice clouds in the Hellas Basin has been observed MARs Color Imager (MARCI) instrument on Mars Reconnaissance Orbiter (MRO) to persist throughout majority Northern Hemisphere (NH) summer. Although are at very low opacities NH spring, they noticeably thicken after Ls 60° and continue do so until their peak optical thickness attained ~120°. They dissipate rapidly from 120° 150°, only southern side basin indistinguishable polar hood...
Abstract C. Leovy (personal communication, 2007) speculated that two stable climate states on early Mars could have resulted from interactions between the dust and CO 2 cycles. In one state, a highly active cycle would prevent atmospheric collapse, in second, collapsed atmosphere not maintain an cycle. An initial assessment of this idea is presented based general circulation model parameter study. A range global loadings, ice albedos, obliquities are investigated to explore conditions which...
Planetary‐scale longitudinal variations in density observed by the Mars Global Surveyor accelerometer 125 km region can be qualitatively reproduced NASA Ames general circulation model 80 altitude region, but only when locations having specific local times are used analysis. If results averaged over all times, high‐altitude nearly disappear, leaving a small stationary wave 1 pattern, consistent with theory and previous modeling studies. This analysis suggests that wavelike structures result...