Search NASA⌕ Search

Engineering topics

Claire E Newman

Publications and source records attributed to Claire E Newman.

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Dynamical Core Damping of Thermal Tides in Martian Atmosphere

Atmospheric oscillations with daily periodicity are observed in in-situ near-surface pressure, temperature, and winds observations, and also in remotely sensed temperature and pressure observations of the Martian atmosphere. Such oscillations are interpreted as thermal tides driven by the diurnal cycle of solar radiation and occur at various frequencies, with the most prominent being the diurnal, semidiurnal, terdiurnal and quadiurnal tides. Mars global circulation models reproduce these tides with varying levels of success. Until recently, both the MarsWRF and newly developed MarsMPAS models were able to produce realistic diurnal and semidiurnal tide amplitudes but predicted higher-order mode amplitudes that were significantly weaker than observed. We use linear wave analysis to show that the divergence damping applied within both MarsWRF and MarsMPAS is responsible for suppressing the amplitude of thermal tides with frequency greater than 2 per sol, despite being designed to suppress only acoustic wave modes. Decreasing the strength of the divergence damping in MarsWRF and MarsMPAS allows for excellent prediction of the higher order tidal modes. This finding demonstrates that care must be taken when applying numerical dampers and filters that may eliminate some desired dynamical features in planetary atmospheres.

Yuan Lian↗
NASA NTRS2022

The Dynamic Atmospheric and Aeolian Environment of Jezero Crater, Mars

Despite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars’s ubiquitous dust haze have not been well quantified in situ, with missions lacking either thenecessary sensors and/or a sufficiently active aeolian environment. Perseverance rover’s novel environmental sensors and Jezero crater’s dusty environment remedy this. In Perseverance’s first 216 sols, four convective vortices raised dust locally, while on average four passed the rover daily, over 25% of which were significantly dusty (‘dust devils’). More rarely, dust lifting by non-vortex wind gusts was produced by daytime convection cells advected over the crater by strong upslope winds, which also control aeolian surface features. One such event covered ten times more area than the largest dust devil, suggesting dust devils and wind gusts could raise equal dust.

Claire E Newman↗
NASA NTRS2021

Gravity Wave Observations by the Mars Science Laboratory REMS Pressure Sensor and Comparison with Mesoscale Atmospheric Modeling with MarsWRF

Surface pressure measurements on Mars have revealed a wide variety of atmospheric phenomena. The Mars Science Laboratory Rover Environmental Monitoring Station pressure sensor dataset is now the longest duration record of surface pressure on Mars. We use the first 2580 martian sols, nearly 4 Mars years,of measurements to identify atmospheric pressure waves with periods of tens of minutes to hours using wavelet analysis on residual pressure after the tidal harmonics are removed. We find these waves have a clear diurnal cycle with strongest activity in the early morning and late evening and a seasonal cycle with the strongest waves in the second half of the martian year (Ls= 180-360°). The strongest such waves of the entire mission occurred during the Mars Year 34 global dust storm. Comparable atmospheric waves are identified using atmospheric modeling with the MarsWRF general circulation model in a “nested” high spatial resolution mode. With the support of the modeling, we find these waves best fit the expected properties of inertia-gravity waves with horizontal wavelengths of O(100s) of km. PLAIN LANGUAGE SUMMARY Measuring air pressure from the surface of Mars has revealed a wide variety of atmospheric phenomena. The Curiosity rover's record or surface air pressure is now the longest yet made on Mars.We use the first ~8 years of Curiosity's pressure observations to look for atmospheric waves with periods of tens of minutes to hours. We find these waves have a clear pattern in their daily behavior with the strongest activity in the early morning and late evening and a seasonal cycle with the strongest waves in the second half of the martian year (Northern hemisphere fall and winter). The strongest such waves occurred in 2018 during a global dust storm. We find comparable waves in atmospheric modeling. With the support of modeling, we find these waves best fit the expected properties of buoyancy waves forced by airflow over topography with horizontal wavelengths of 100-1000 km.

Scott D Guzewich↗
NASA NTRS2020

Toward More Realistic Simulation and Prediction of Dust Storms on Mars

Major (regional and global)dust storms dominate weather and climate variability on present-day Mars. Absorption and scattering of visible and IR radiation by dust strongly affect the thermal state of the thin Mars atmosphere, while dust provides condensation nuclei for water and CO2 cloud particles, which also affect radiative fluxes. Global dust storms (GDS) occur ~three times per Mars decade and to date have been observed in only northern fall and winter,when the global circulation is strongest. Tenfold increases in column dust opacity are typical during GDS, with intense vertical motions transporting dust to far higher altitudes than usual. The key processes and feedbacks that produce GDS remain poorly understood, hence current atmospheric models fail to self-consistently simulate observed dust storm activity. This means we have no predictive capability for when GDS may occur, either now or in Mars’s past. And crucially, due to the huge impact of GDS on the atmosphere and surface, our lack of ability to simulate realistic dust storms has major implications for Mars science and exploration: from understanding the present climate (§2.1),to modeling past climates and water cycles (§2.2), to exploring how wind, water, and dust cycles varied over time to interpret geology and assess potential habitability(§2.3), to quantifying and mitigating risks posed to Mars missions (§2.4)

Claire E Newman↗