Miguel Angel de Pablo

Episodic flood inundations of the northern plains of Mars

Throughout the recorded history of Mars, liquid water has distinctly shaped its landscape, including the prominent circum-Chryse and the nnorthwestern slope valleys outflow channel systems, and the extremely flat northern plains topography at the distal reaches of these outflow nchannel systems. Paleotopographic reconstructions of the Tharsis magmatic complex reveal the existence of an Europe-sized Noachian ndrainage basin and subsequent aquifer system in eastern Tharsis. This basin is proposed to have sourced outburst floodwaters that sculpted the noutflow channels, and ponded to form various hypothesized oceans, seas, and lakes episodically through time. These floodwaters decreased nin volume with time due to inadequate groundwater recharge of the Tharsis aquifer system. Martian topography, as observed from the Mars nOrbiter Laser Altimeter, corresponds well to these ancient flood inundations, including the approximated shorelines that have been proposed nfor the northern plains. Stratigraphy, geomorphology, and topography record at least one great Noachian-Early Hesperian northern plains nocean, a Late Hesperian sea inset within the margin of the high water marks of the previous ocean, and a number of widely distributed nminor lakes that may represent a reduced Late Hesperian sea, or ponded waters in the deepest reaches of the northern plains related to minor nTharsis- and Elysium-induced Amazonian flooding.

Curiosity's rover environmental monitoring station: Overview of the first 100 sols

In the first 100 Martian solar days (sols) of the Mars Science Laboratory mission, the Rover Environmental Monitoring Station (REMS) measured the seasonally evolving diurnal cycles of ultraviolet radiation, atmospheric pressure, air temperature, ground temperature, relative humidity, and wind within Gale Crater on Mars. As an introduction to several REMS-based articles in this issue, we provide an overview of the design and performance of the REMS sensors and discuss our approach to mitigating some of the difficulties we encountered following landing, including the loss of one of the two wind sensors. We discuss the REMS data set in the context of other Mars Science Laboratory instruments and observations and describe how an enhanced observing strategy greatly increased the amount of REMS data returned in the first 100 sols, providing complete coverage of the diurnal cycle every 4 to 6 sols. Finally, we provide a brief overview of key science results from the first 100 sols. We found Gale to be very dry, never reaching saturation relative humidities, subject to larger diurnal surface pressure variations than seen by any previous lander on Mars, air temperatures consistent with model predictions and abundant short timescale variability, and surface temperatures responsive to changes in surface properties and suggestive of subsurface layering.

Observations and preliminary science results from the first 100 sols of MSL Rover Environmental Monitoring Station ground temperature sensor measurements at Gale Crater

We describe preliminary results from the first 100 sols of ground temperature measurements along the Mars Science Laboratorys traverse from Bradbury Landing to Rocknest in Gale. The ground temperature data show long-term increases in mean temperature that are consistent with seasonal evolution. Deviations from expected temperature trends within the diurnal cycle are observed and may be attributed to rover and environmental effects. Fits to measured diurnal temperature amplitudes using a thermal model suggest that the observed surfaces have thermal inertias in the range of 265–375u2009J m−2 K−1 s−1/2, which are within the range of values determined from orbital measurements and are consistent with the inertias predicted from the observed particle sizes on the uppermost surface near the rover. Ground temperatures at Gale Crater appear to warm earlier and cool later than predicted by the model, suggesting that there are multiple unaccounted for physical conditions or processes in our models. Where the Mars Science Laboratory (MSL) descent engines removed a mobile layer of dust and fine sediments from over rockier material, the diurnal temperature profile is closer to that expected for a homogeneous surface, suggesting that the mobile materials on the uppermost surface may be partially responsible for the mismatch between observed temperatures and those predicted for materials having a single thermal inertia. Models of local stratigraphy also implicate thermophysical heterogeneity at the uppermost surface as a potential contributor to the observed diurnal temperature cycle.

Recent Warming and Cooling in the Antarctic Peninsula Region has Rapid and Large Effects on Lichen Vegetation

The Antarctic Peninsula has had a globally large increase in mean annual temperature from the 1951 to 1998 followed by a decline that still continues. The challenge is now to unveil whether these recent, complex and somewhat unexpected climatic changes are biologically relevant. We were able to do this by determining the growth of six lichen species on recently deglaciated surfaces over the last 24 years. Between 1991 and 2002, when mean summer temperature (MST) rose by 0.42u2009°C, five of the six species responded with increased growth. MST declined by 0.58u2009°C between 2002 and 2015 with most species showing a fall in growth rate and two of which showed a collapse with the loss of large individuals due to a combination of increased snow fall and longer snow cover duration. Increased precipitation can, counter-intuitively, have major negative effects when it falls as snow at cooler temperatures. The recent Antarctic cooling is having easily detectable and deleterious impacts on slow growing and highly stress-tolerant crustose lichens, which are comparable in extent and dynamics, and reverses the gains observed over the previous decades of exceptional warming.

Geology of the Ariadnes Basin, NE Eridania quadrangle, Mars – 1:1Million

Here we present a 1:1,000,000 geological map of the Ariadnes basin (31–38° S, 170–179° E) (Mars), which is one of the topographic depressions located between Terra Sirenum and Terra Cimmeria in the Martian highlands. This basin is diverse, both in terms of morphology and mineralogy, and it is a site of major interest to study the chronological boundary between the Noachian and Hesperian periods (∼3.71u2005Ga). However, a detailed map of the area has not yet been published. The map described in this paper was produced through the analysis of recent images and topographic data that allow the definition of the geologic units with unprecedented detail. We distinguished eight units and diverse tectonic and geomorphic features. We also examined the regional stratigraphy by age determination using crater counting in order to constrain the geological history of the Ariadnes basin. The map provides a basis for which later analyses can build understanding of the regional paleoenvironment.

Active layer monitoring in Antarctica: an overview of results from 2006 to 2015

Monitoring of active layer thawing depth and active layer thickness (ALT), using mechanical pronging and continuous temperature data logging, has been undertaken under the Circumpolar Active Layer ...