Jung-Rack Kim

Selection of the landing site in Isidis Planitia of Mars probe Beagle 2

This paper describes selection and characterization of the landing site for the Mars 2004 Beagle 2 mission. The site is within Isidis Planitia between 10°–12°N, 266°–274°W, centered at 11.6°N, 269.5°W. This is at low elevation (-3600 to -3900 m MOLA), is flat (MOLA RMS slope = 0.57°), radar data suggest a smoother surface at decimeter to meter scales than the Pathfinder site and it has a moderate rock abundance (2–17%, mean 11%). In addition to this, Isidis shows evidence for concentration and remobilization of volatiles. In particular, the basin contains conical landforms. We favor models involving the formation of tuff cones during magma-ice interaction. Structures identified as dykes in MOC images may be remnants of magma conduits. The pattern of bulk thermal inertia in Isidis (higher values of 500 Jm-2s-0.5K-1 around the SW-S-E margin decreasing toward the center and north) suggests that an influx of sediment spread from the Noachian areas around the southern half of the basin over the basin floor. The coarse, higher thermal inertia material was deposited closest to the sediment source. The variable state of erosion of the tuff cones suggests that they formed intermittently over a long period of time during Amazonian and possibly Hesperian epochs. Geologically recent resurfacing of Isidis has also occurred by aeolian processes, and this is shown by a deficit in impact craters <120 m diameter. The proportion of rocky material is predicted to be slightly less than the Viking and Pathfinder sites, but there will probably be more duricrust.

Late Noachian to Hesperian climate change on Mars: Evidence of episodic warming from transient crater lakes near Ares Vallis

[1] The Ares Vallis region is surrounded by highland terrain containing both degraded and pristine large impact craters that suggest a change in climate during the Late Noachian-Early Hesperian, from warmer, wetter conditions to colder, dryer conditions. However, the regional occurrence of Hesperian-age crater outlet channels indicates that this period on Mars was characterized by episodic climate fluctuations that caused transient warming, facilitating the stability of liquid water at the surface. An extensive survey of the morphology and topography of 75 impact basins in the region indicates that of the largest degraded craters, 4 were identified with single outlet channels that suggest the former presence of water infill. These basins lack inlets indicating that water influx was likely derived from sapping of groundwater. A comparison of measured crater rim heights to modeled rim heights suggests that the bulk of the depth/diameter reduction on these craters was the result of infilling, possibly by sediments. Crater statistics indicate that crater degradation and infill occurred during a short 200 Ma interval in the Late Noachian, from 3.8 Ga to 3.6 Ga. Craters that formed after 3.6 Ga exhibit a near-pristine morphology. Our results support the hypothesis of rapid climate change at the end of the Noachian period. However, geologic relationships between the crater outlet channels and Ares Vallis indicate that drainage occurred only after the period of intense crater modification, during the Hesperian (3.5-2.9 Ga). This suggests a delay between the time of infill of the craters and the time of drainage.

Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars

On Earth, permafrost thawing is linked to climate warming. Similarly, on Mars, permafrost degradation, described from mid-latitude and equatorial settings, is likely linked to global or regional climate change. Putative thermokarst depressions identified on Mars are widely considered to be the result of sublimation, evaporation, or thawing of an ice-rich substrate. The possibility that the depressions formed by melting of permafrost to create alas-like lakes has been recently proposed, but is controversial, owing to the lack of primary evidence for liquid filling the depressions. Here we use high-resolution Mars Reconnaissance Orbiter Context Camera images and derived topographic data to characterize possible thermokarst terrain in Ares Vallis. The terrain comprises subcircular to irregular, flat-floored rimless topographic depressions that occur at varying elevations. We report the discovery of narrow channels connecting thermokarst-like depressions that provide evidence for the previous presence of ponded liquid water. Crater counts on these surfaces indicate resurfacing that is likely related to flood deposition of water-saturated sediments in Ares Vallis during the Hesperian (ca. 3.6–3.0 Ga). We infer that thermokarst lakes formed after flooding by thawing of ice within the sediments during transient warm periods in the Hesperian, a time previously considered to be too cold to permit ice thaw.

Retreat of a giant cataract in a long-lived (3.7-2.6 Ga) martian outflow channel

We describe the evolution of an similar to 600-m-deep tributary outflow channel to Ares Vallis, Mars. High-resolution topography, image analysis, and crater statistics indicate that this tributary canyon developed by the upstream migration of a large, similar to 300-m-tall cataract during multiple flood events that span similar to 1 b.y. of Mars history (3.7-2.6 Ga). Issuing from Hydapsis Chaos, these floods were initiated at a similar time and occurred over a similar time range to flooding in Ares Vallis, suggesting a potential regional control on flood initiation and chaos formation. In addition, we provide evidence that cataract retreat and significant incision within the tributary canyon occurred only after a series of downcutting events within Ares Vallis. Topography data and crater statistics taken from the floor of Ares Vallis indicate an similar to 300 m base-level drop that coincides temporally with an Early Amazonian (ca. 2.6 Ga) flood event and cataract formation within the tributary canyon. The results both confirm the hypothesis of long-term, multiple flood events within martian outflow channels and demonstrate the influence of base-level change on their incision.

Tree and building detection in dense urban environments using automated processing of IKONOS image and LiDAR data

The automated detection and reconstruction of artificial structures, larger than 10 m2 in area using high resolution satellite images and Light Detection and Ranging (LiDAR) data through 3-dimensional shapes and/or 2-dimensional boundaries is described here. Additionally, it is demonstrated how individual tree crowns have been detected with more than 90% accuracy in very dense urban environments from very high-resolution images and range data. Pre-existing machine vision algorithms and techniques were modified and updated for this particular application to building detection within dense urban areas. All products from such procedures have not only been demonstrated with a significant areal coverage but have also been quantitatively assessed against manually obtained and third party mapping data. Accuracies of around 85% have been achieved for building detection and almost 95% for tree crown detection.

Mechanisms and timescales of fluvial activity at Mojave and other young Martian craters

Mojave Crater, and five other relatively young Late Hesperian to Amazonian-age Martian craters exhibit channelized alluvial fans that are sourced from bedrock-eroded catchments. These catchments emerge from the crests of sloping surfaces, suggesting a formation mechanism that involved precipitation. The evidence for fluvial activity at all six craters is restricted to their interiors and the immediate surrounding regions. Detailed mapping at Mojave reveals the highest density of channels, catchments and fans interior to the crater. Similar landforms are identified outside of the crater, but not beyond ~200 km from the rim. Irregular pits on the floor of Mojave, interpreted as degassing structures from hot impact melt, directly superpose several fan surfaces, and partly destroy the fan toes. This suggests that sediment was mobilized immediately after crater formation, while the crater was still hot. Based on the patterns and timing of channel-fan development at all six craters we favor several hypotheses for the precipitation mechanism: (1) snowfall and melt on young, hot impact craters, (2) impact plume precipitation, and (3) degassing of volatiles from impact melt terrain. Scenario (1) suggests a different global or regional climate relative to modern conditions, requiring equatorial and midlatitude snowfall accumulation. Scenarios (2) and (3) do not necessarily require unique climate conditions, as water may have been mobilized from the target or the impactor.

Implementation of Martian virtual reality environment using very high-resolution stereo topographic data

Topography over terrestrial or other planetary surfaces is an important base data for virtual reality construction. In particular, with inaccessible topography such as the Martian surface, virtual reality provides great value not only for public interaction but also for scientific research. For the latter application, since field surveys are essential for the geological and geomorphological researches, the virtual reality environment created based on verified topographic products provides an alternative solution for planetary research. The performance of virtual reality implementation over a planetary surface can be assessed by two major factors: (1) The geodetically controlled base topographic products, such as DTM and ortho-image, and (2) Technological integration of topographic products into virtual reality software and hardware. For the first aspect, the multi-resolution stereo analysis approach has already provided a solid basis so that specific topographic data sets over testing areas were generated by the hierarchical processor. To address the second problem, a parallel processor with multiple screen display combining 3D display software was employed in this research. As demonstrated in this paper, the constructed Martian virtual environment showed highly detailed features over the Athabasca Valles (one of former potential Mars Exploration Rover landing sites) and Eberswalde crater (one of the main original landing candidates for the NASAs rover mission scheduled to launch in late 2011). The employment of such virtual reality environments is expected to be a powerful simulator after integrating a 3D Martian model, engineering and environment constraints for Martian geological and geomorphic researches including landing site selection and rover navigation.

Toward generalized planetary stereo analysis scheme—Prototype implementation with multi-resolution Martian stereo imagery

Stereo analysis of orbital imagery is highly valuable for scientific research in planetary surface. Thus, the processing of planetary stereo imagery has been progressed with various approaches and resulted in a series of uncontrolled topographic products. In order to fully utilize the data derived from image systems carried on various planetary orbiters, the generalized algorithms of stereo image processing and Digital Terrain Model (DTM) extraction have been developed. Based on Kim and Muller’s approach (2009), the algorithms were updated employing the feed-forwarded model-based matcher and the generic sensor model. It is a sort of iterative stereo procedure delivering the reference data to next stage for 3D zoom-up. Thus the system is capable of processing various stereo data sets with the generic approach and achieves stable photogrammetric accuracy of resultant DTMs. To demonstrate the potential of this stereo processing routine, the DTMs obtained from various Mars orbital images covering some sample test sites were processed with the prototype processor. As the result, the processed DTMs clearly illustrated detailed geological features and high agreement with the height spots of Mars Obiter Laser Altimeter (MOLA). It was proved that the overall processing strategy in this paper was effective and the topographic products were accurate and reliable.

Investigation of Potential Volcanic Risk from Mt. Baekdu by DInSAR Time Series Analysis and Atmospheric Correction

Mt. Baekdu is a volcano near the North Korea-Chinese border that experienced a few destructive eruptions over the course of its history, including the well-known 1702 A.D eruption. However, signals of unrest, including seismic activity, gas emission and intense geothermal activity, have been occurring with increasing frequency over the last few years. Due to its close vicinity to a densely populated area and the high magnitude of historical volcanic eruptions, its potential for destructive volcanic activity has drawn wide public attention. However, direct field surveying in the area is limited due to logistic challenges. In order to compensate for the limited coverage of ground observations, comprehensive measurements using remote sensing techniques are required. Among these techniques, Differential Interferometric SAR (DInSAR) analysis is the most effective method for monitoring surface deformation and is employed in this study. Through advanced atmospheric error correction and time series analysis, the accuracy of the detected displacements was improved. As a result, clear uplift up to 20 mm/year was identified around Mt. Baekdu and was further used to estimate the possible deformation source, which is considered as a consequence of magma and fault interaction. Since the method for tracing deformation was proved feasible, continuous DInSAR monitoring employing upcoming SAR missions and advanced error regulation algorithms will be of great value in monitoring comprehensive surface deformation over Mt. Baekdu and in general world-wide active volcanoes.

Land Cover Analysis with High-Resolution Multispectral Satellite Imagery and Its Application for the CO2 Flux Estimation

The global warming caused by CO2 greenhouse effect becomes a world wide critical issue nowadays. In order to make suitable and sustainable policies for fully managing and monitoring the CO2 emission and reduction, the identification of CO2 volume and spatial distribution is highly crucial for the local environmental authorities. Therefore, an indirect measurement method using land cover classes and their CO2 emission estimation per unit area driven from the sample survey or statistical analysis was proposed in this chapter. To prove the feasibility, Boryeong and Yoengi cities in South Korea were selected as the two test sites, and CO2 emission maps covering these areas were produced using the proposed method. One of the key factors for a successful mapping of CO2 emission was to produce an accurate land cover map over the test site. To achieve this, the Rapideye satellite imagery with characteristics of high-resolution and multispectral was chosen as the main data source for land cover analysis. Together with the SPOT satellite images and GIS land-use data, the accurate land cover map was created. The emission ratio of each land cover type was subsequently applied on the land cover map to produce CO2 emission map and also estimate the total CO2 flux.