Search Publications

Characteristics of the Basal Interface of the Martian South Polar Layered Deposits
DOI: 10.1029/2021GL093631 Bibcode: 2021GeoRL..4893631K

Plaut, Jeffrey J.; Khuller, Aditya R.

We expand on previous studies of the South Polar Layered Deposits' (SPLD) basal interface using data acquired by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) to obtain detailed maps of elevation, topography, and reflected radar power. Using these maps, we derive the thickness (ranging from 0 to 3.7 km) and volume of the…

2021 Geophysical Research Letters
MEx 18
Configuration of the Earth's Magnetotail Current Sheet
DOI: 10.1029/2020GL092153 Bibcode: 2021GeoRL..4892153A

Lin, Yu; Zhang, Xiao-Jia; El-Alaoui, Mostafa +7 more

The spatial scale and intensity of Earth's magnetotail current sheet determine the magnetotail configuration, which is critical to one of the most energetically powerful phenomena in the Earth's magnetosphere, substorms. In the absence of statistical information about plasma currents, theories of the magnetotail current sheets were mostly based on…

2021 Geophysical Research Letters
Cluster 18
Evolution of the Horizontal Winds in Jupiter's Great Red Spot From One Jovian Year of HST/WFC3 Maps
DOI: 10.1029/2021GL093982 Bibcode: 2021GeoRL..4893982W

de Pater, Imke; Wong, Michael H.; Simon, Amy A. +3 more

We measured the horizontal winds in Jupiter's Great Red Spot (GRS) using data from the WFC3/UVIS instrument on board the Hubble Space Telescope (HST). The data cover 11 epochs from 2009 to 2020. Long-term monotonic trends in size and shape previously noted from the visible cloud appearance are paralleled by changes in the high-speed ring around th…

2021 Geophysical Research Letters
eHST 17
Ultralow Frequency Waves in Driving Jovian Aurorae Revealed by Observations From HST and Juno
DOI: 10.1029/2020GL091579 Bibcode: 2021GeoRL..4891579P

Grodent, Denis; Bonfond, Bertrand; Wei, Yong +6 more

Large scale electrical currents and Alfvénic waves are the two main drivers responsible for producing planetary aurorae. The relative contribution of each process is a central question in terrestrial auroral science, and poorly understood for other planets due to the relatively rare opportunity of in situ spacecraft measurements. Here, we present …

2021 Geophysical Research Letters
eHST 17
First Detection and Thermal Characterization of Terminator CO2 Ice Clouds With ExoMars/NOMAD
DOI: 10.1029/2021GL095895 Bibcode: 2021GeoRL..4895895L

Vandaele, Ann Carine; Stolzenbach, Aurélien; Aoki, Shohei +16 more

We present observations of terminator CO2 ice clouds events in three groups: Equatorial dawn, Equatorial dusk (both between 20°S and 20°N) and Southern midlatitudes at dawn (45°S and 55°S east of Hellas Basin) with ESA ExoMars Trace Gas Orbiter's Nadir and Occultation for MArs Discovery instrument. CO2 ice abundance is retrie…

2021 Geophysical Research Letters
ExoMars-16 16
Causes of Jets in the Quasi-Perpendicular Magnetosheath
DOI: 10.1029/2021GL093173 Bibcode: 2021GeoRL..4893173K

Kajdič, Primož; Raptis, Savvas; Blanco-Cano, Xóchitl +1 more

Magnetosheath jets are currently an important topic in the field of magnetosheath physics. It is thought that 97% of the jets are produced by the shock rippling at quasi-parallel shocks. Recently, large statistical studies of magnetosheath jets have been performed, however, it is not clear whether rippling also produces jets found downstream of qu…

2021 Geophysical Research Letters
Cluster 16
Delta Deposits on Mars: A Global Perspective
DOI: 10.1029/2021GL094271 Bibcode: 2021GeoRL..4894271D

Hauber, E.; Breuer, D.; De Toffoli, B. +1 more

Deltas have long been considered a constraining element to reconstruct the water level of an ancient ocean that may have once occupied the northern lowlands of Mars, and recently this hypothesis started to be challenged. We investigate this hypothesis and present a global inventory of fan-shaped features showing typical deltaic traits across the e…

2021 Geophysical Research Letters
MEx 14
Probing the Atmospheric Cl Isotopic Ratio on Mars: Implications for Planetary Evolution and Atmospheric Chemistry
DOI: 10.1029/2021GL092650 Bibcode: 2021GeoRL..4892650L

Vandaele, Ann Carine; Aoki, Shohei; Liuzzi, Giuliano +22 more

Following the recent detection of HCl in the atmosphere of Mars by ExoMars/Trace Gas Orbiter, we present here the first measurement of the 37Cl/35Cl isotopic ratio in the Martian atmosphere using a set of Nadir Occultation for MArs Discovery (NOMAD) observations. We determine an isotopic anomaly of −6 ± 78‰ compared to Earth …

2021 Geophysical Research Letters
ExoMars-16 12
New Results on the Direct Observations of Thermal Radio Emission from a Solar Coronal Mass Ejection
DOI: 10.1029/2020GL091048 Bibcode: 2021GeoRL..4891048R

Ramesh, R.; Kumari, A.; Kathiravan, C. +2 more

We report observations of thermal emission from the frontal structure of a coronal mass ejection (CME) using data obtained with the Gauribidanur RAdioheliograPH simultaneously at 80 and 53 MHz on May 1, 2016. The CME was due to activity on the far side of the Sun, but near its limb. No nonthermal radio burst activity was noticed. This provided an …

2021 Geophysical Research Letters
SOHO 11
A Long Term Study of Mars Mesospheric Clouds Seen at Twilight Based on Mars Express VMC Images
DOI: 10.1029/2020GL092188 Bibcode: 2021GeoRL..4892188H

Hueso, R.; Sánchez-Lavega, A.; Titov, D. +5 more

We present the first systematic study of clouds observed during twilight on Mars. We analyze images obtained by the Visual Monitoring Camera on Mars Express between 2007 and 2020. Using an automated retrieval algorithm, we found 407 cases of clouds observed at twilight, in which the geometry of the observations allows to derive the minimum altitud…

2021 Geophysical Research Letters
MEx 10