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7. Glacier and lake level change from TOPEX-series and Cryosat-2 altimeters in Tanggula: Comparison with satellite imagery

Author

Hwang, Cheinway, Wei, Shiang-Hung, Cheng, Yung-Sheng, Abulaitijiang, Adili, Andersen, Ole Baltazar, Chao, Nengfang, Peng, Hsin-Ya, Tseng, Kuo-Hsin, Lee, Jui-Chi, Hwang, Cheinway, Wei, Shiang-Hung, Cheng, Yung-Sheng, Abulaitijiang, Adili, Andersen, Ole Baltazar, Chao, Nengfang, Peng, Hsin-Ya, Tseng, Kuo-Hsin, and Lee, Jui-Chi

Abstract

We detect long-term elevation changes near a glacier terminus and an icefield in Tanggula Mountains from altimeter data from the TOPEX/Poseidon (T/P), Jason-1 (J1), Jason-2 (J2), and Jason-3 (J3) altimeters. An altimeter processing technique is developed for the detection, including waveform retracking, quality data selection, and elevation adjustment. The altimeter-observed glacier thinning is confirmed by the direct elevation differences between the digital elevation models from the satellite missions TanDEM-X and SRTM, and by the glacier area losses from Landsat images. At the two glacier sites, the altimeter-derived elevations show seasonal oscillations, with mean rates of -3.71 ± 0.3 and -3.08 ± 0.20 m year-1 over 1993–2002 (T/P only), and -1.88 ± 0.06 and -1.46 ± 0.07 m year-1 over 1993–2020 (T/P-Jason altimeters), with abnormal changes around the 1997–1998 El Niño. The declining rates suggest that the persistent losses of glaciers in Tanggula Mountains can no longer sustain the large thinning rates. The glacier feeds the nearby Chibuzhang Co lake, and lake level and glacier level changes from Cryosat-2 are consistent with those from the T/P-Jason altimeters. The glacier meltwater contributed to the accelerated rise of the glacier-fed Chibuzhang Co, at a rate of 0.15 ± 0.05 m year-1 over 1993–2002, increasing to 0.42 ± 0.01 m year-1 over 2003–2020. The lake levels of Chibuzhang Co experienced notable drops after the 1997–1998 and 2014–2016 El Niño. The Cryosat-2 result shows the altitude effect of glacier change: the higher the glacier, the less it melts. A repeat altimeter can provide time-lapsed elevation measurements as a virtual glacier station to monitor glacier melt caused by climate change.

Published
2021

11. First analysis of the size-frequency distribution of boulders ≥ 7m on comet 67P

Author

Pajola, Maurizio, Vincent, Jean-Baptiste, Güttler, Carsten, Lee, Jui-Chi, Massironi, Matteo, Bertini, Ivano, Simioni, Emanuele, Marzari, Francesco, Giacomini, Lorenza, Barbieri, Cesare, Cremonese, Gabriele, Naletto, Giampiero, Pommerol, Antoine, El-Maarry, Mohamed Ramy, Besse, Sébastien, Küppers, Michael, La Forgia, Fiorangela, Lazzarin, Monica, Thomas, Nicholas, Auger, Anne-Thérèse, Ip, W.-H., Lin, Zhong-Yi, Sierks, Holger, A'Hearn, M. F., Barucci, Maria Antonella, Bertaux, Jean-Loup, da Deppo, Vania, Davidsson, Björn, de Cecco, M., Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Keller, Horst Uwe, Knollenberg, Jörg, Koschny, Detlef, Kramm, Rainer, Kürt, Ekkehard, Lamy, Philippe, Lara, Luisa M., López-Moreno, José J., Magrin, Sara, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Oklay, Nilda, Preusker, Frank, Rickman, Hans, Rodrigo, Rafael, Scholten, Frank, Tubiana, Cecilia, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Università degli Studi di Trento (UNITN), Department of Industrial Engineering [Padova], Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, and Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR)

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2016

12. Novel Multitemporal Synthetic Aperture Radar Interferometry Algorithms and Models Applied on Managed Aquifer Recharge and Fault Creep

Author

Lee, Jui-Chi

Subjects
Sentinel-1, InSAR Time Series, Atmospheric Delay, Pair Selection, San Andreas Fault, Poroelastic Modeling
Abstract

The launch of Sentinel-1A/B satellites in 2014 and 2016 marked a pivotal moment in Synthetic Aperture Radar (SAR) technology, ushering in a golden era for SAR. With a revisit time of 6–12 days, these satellites facilitated the acquisition of extensive stacks of high-resolution SAR images, enabling advanced time series analysis. However, processing these stacks posed challenges like interferometric phase degradation and tropospheric phase delay. This study introduces an advanced Small Baseline Subset (SBAS) algorithm that optimizes interferometric pairs, addressing systematic errors through dyadic downsampling and Delaunay Triangulation. A novel statistical framework is developed for elite pixel selection, considering distributed and permanent scatterers, and a tropospheric error correction method using smooth 2D splines effectively identifies and removes error components with fractal-like structures. Beyond geodetic technique advancements, the research explores geological phenomena, detecting five significant slow slip events (SSEs) along the Southern San Andreas Fault using multitemporal SAR interferometric time series from 2015-2021. These SSEs govern aseismic slip dynamics, manifesting as avalanche-like creep rate variations. The study further investigates Managed Aquifer Recharge (MAR) as a nature-engineering-based solution in the Santa Ana Basin. Analyzing surface deformation from 2004 to 2022 demonstrates MAR's effectiveness in curbing land subsidence within Orange County, CA. Additionally, MAR has the potential to stabilize nearby faults by inducing a negative Coulomb stress change. Projecting into the future, a suggested 2% annual increase in recharge volume through 2050 could mitigate land subsidence and reduce seismic hazards in coastal cities vulnerable to relative sea level rise. This integrated approach offers a comprehensive understanding of geological processes and proposes solutions to associated risks.

Published
2024

13. The southern hemisphere of 67P/Churyumov-Gerasimenko : Analysis of the preperihelion size-frequency distribution of boulders >= 7m

Author

Pajola, Maurizio, Lucchetti, Alice, Vincent, Jean-Baptiste, Oklay, Nilda, El-Maarry, Mohamed R., Bertini, Ivano, Naletto, Giampiero, Lazzarin, Monica, Massironi, Matteo, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Boudreault, Steve, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjorn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Gicquel, Adeline, Groussin, Olivier, Gutierrez, Pedro J., Guetler, Carsten, Hofmann, Marc, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lee, Jui-Chi, Lin, Zhong-Yi, Lopez Moreno, Jose J., Marzari, Francesco, Michalik, Harald, Mottola, Stefano, Preusker, Frank, Scholten, Frank, Thomas, Nicholas, Toth, Imre, Tubiana, Cecilia, Pajola, Maurizio, Lucchetti, Alice, Vincent, Jean-Baptiste, Oklay, Nilda, El-Maarry, Mohamed R., Bertini, Ivano, Naletto, Giampiero, Lazzarin, Monica, Massironi, Matteo, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Boudreault, Steve, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjorn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Gicquel, Adeline, Groussin, Olivier, Gutierrez, Pedro J., Guetler, Carsten, Hofmann, Marc, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lee, Jui-Chi, Lin, Zhong-Yi, Lopez Moreno, Jose J., Marzari, Francesco, Michalik, Harald, Mottola, Stefano, Preusker, Frank, Scholten, Frank, Thomas, Nicholas, Toth, Imre, and Tubiana, Cecilia

Abstract

Aims. We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 2 May 2015 at a distance of 125 km from the nucleus. The scale of this dataset is 2.3 m/px; the high resolution of the images, coupled with the favorable observation phase angle of 62 degrees, provided the possibility to unambiguously identify boulders >= 7 m on the surface of 67P and to manually extract them with the software ArcGIS. We derived the size-frequency distribution of the illuminated southern hemisphere. Results. We found a power-law index of -3.6 +/- 0.2 for the boulders on the southern hemisphere with a diameter range of 7-35 m. The power-law index is equal to the one previously found on northern and equatorial regions of 67P, suggesting that similar boulder formation processes occur in both hemispheres. The power-law index is related to gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. In addition, the presence of a larger number of boulders per km(2) in the southern hemisphere, which is a factor of 3 higher with respect to the northern hemisphere, suggests that the southernmost terrains of 67P are affected by a stronger thermal fracturing and sublimating activity, hence possibly causing larger regressive erosion and gravitational events.

Published
2016
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14. Aswan site on comet 67P/Churyumov-Gerasimenko : Morphology, boulder evolution, and spectrophotometry

Author

Pajola, Maurizio, Oklay, Nilda, La Forgia, Fiorangela, Giacomini, Lorenza, Massironi, Matteo, Bertini, Ivano, El-Maarry, M. R., Marzari, Francesco, Preusker, Frank, Scholten, Frank, Hoefner, Sebastian, Lee, Jui-Chi, Vincent, Jean-Baptiste, Groussin, Olivier, Naletto, Giampiero, Lazzarin, Monica, Barbieri, Cesare, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Cremonese, Gabriele, Da Deppoll, Vania, Davidsson, Bjoern, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Guettler, Carsten, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kueppers, Michael, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Moreno, Jose J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Thomas, Nicholas, Tubiana, Cecilia, Pajola, Maurizio, Oklay, Nilda, La Forgia, Fiorangela, Giacomini, Lorenza, Massironi, Matteo, Bertini, Ivano, El-Maarry, M. R., Marzari, Francesco, Preusker, Frank, Scholten, Frank, Hoefner, Sebastian, Lee, Jui-Chi, Vincent, Jean-Baptiste, Groussin, Olivier, Naletto, Giampiero, Lazzarin, Monica, Barbieri, Cesare, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Cremonese, Gabriele, Da Deppoll, Vania, Davidsson, Bjoern, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Guettler, Carsten, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kueppers, Michael, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Moreno, Jose J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Thomas, Nicholas, and Tubiana, Cecilia

Abstract

Aims. We provide a detailed morphological analysis of the Aswan site on comet 67P/Churyumov-Gerasimenko (67P). We derive the size-frequency distribution of boulders >= 2 m and correlate this distribution with the gravitational slopes for the first time on a comet. We perform the spectral analysis of this region to understand if possible surface variegation is related to the different surface textures observable on the different units. Methods. We used two OSIRIS Narrow Angle Camera (NAC) image data sets acquired on September 19 and 22, 2014, with a scale of 0.5 m/px. Gravitational slopes derived from the 3D shape model of 67P were used to identify and interpret the different units of the site. By means of the high-resolution NAC data sets, boulders >= 2.0 m can be unambiguously identified and extracted using the software ArcGIS. Coregistered and photometrically corrected color cubes were used to perform the spectral analyses, and we retrieved the spectral properties of the Aswan units. Results. The high-resolution morphological map of the Aswan site (0.68 km(2)) shows that this site is characterized by four different units: fine-particle deposits located on layered terrains, gravitational accumulation deposits, taluses, and the outcropping layered terrain. Multiple lineaments are identified on the Aswan cliff, such as fractures, exposed layered outcrops, niches, and terraces. Close to the terrace margin, several arched features observed in plan view suggest that the margin progressively retreats as a result of erosion. The size-frequency of boulders >= 2 m in the entire study area has a power-law index of -3.9 +0.2/-0.3 (1499 boulders >= 2 m/km(2)), suggesting that the Aswan site is mainly dominated by gravitational events triggered by sublimation and/or thermal insolation weathering causing regressive erosion. The boulder size-frequency distribution versus gravitational slopes indicates that when higher gravitational slope terrains are considered, only

Published
2016
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15. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
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16. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
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17. Gas outflow and dust transport of comet 67P/Churyumov–Gerasimenko

Author

Lai, Ian-Lin, primary, Ip, Wing-Huen, additional, Su, Cheng-Chin, additional, Wu, Jong-Shinn, additional, Lee, Jui-Chi, additional, Lin, Zhong-Yi, additional, Liao, Ying, additional, Thomas, Nicolas, additional, Sierks, Holger, additional, Barbieri, Cesare, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst Uwe, additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria Antonella, additional, Bertaux, Jean-Loup, additional, Bertini, Ivano, additional, Boudreault, Steven, additional, Cremonese, Gabriele, additional, Da Deppo, Vania, additional, Davidsson, Björn, additional, Debei, Stefano, additional, De Cecco, Mariolino, additional, Deller, Jakob, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Groussin, Olivier, additional, Gutiérrez, Pedro J., additional, Güttler, Carsten, additional, Hofmann, Marc, additional, Hviid, Stubbe F., additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kovacs, Gabor, additional, Kramm, J.-Rainer, additional, Kührt, Ekkehard, additional, Küppers, Michael, additional, Lara, Luisa M., additional, Lazzarin, Monica, additional, Lopez Moreno, Josè J., additional, Marzari, Francesco, additional, Naletto, Giampiero, additional, Oklay, Nilda, additional, Shi, Xian, additional, Tubiana, Cecilia, additional, and Vincent, Jean-Baptiste, additional

Published
2016
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18. Geomorphological mapping of comet 67P/Churyumov–Gerasimenko’s Southern hemisphere

Author

Lee, Jui-Chi, primary, Massironi, Matteo, additional, Ip, Wing-Huen, additional, Giacomini, Lorenza, additional, Ferrari, Sabrina, additional, Penasa, Luca, additional, El-Maarry, Mohamed Ramy, additional, Pajola, Maurizio, additional, Lai, Ian-Lin, additional, Lin, Zhong-Yi, additional, Ferri, Francesca, additional, Sierks, Holger, additional, Barbieri, Cesare, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst Uwe, additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria Antonella, additional, Bertaux, Jean-Loup, additional, Bertini, Ivano, additional, Cremonese, Gabriele, additional, Da Deppo, Vania, additional, Davidsson, Björn, additional, Debei, Stefano, additional, De Cecco, Mariolino, additional, Deller, Jakob, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Groussin, Olivier, additional, Gutiérrez, Pedro J., additional, Güttler, Carsten, additional, Hofmann, Marc, additional, Hviid, Stubbe F., additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kovacs, Gabor, additional, Kramm, J.-Rainer, additional, Kührt, Ekkehard, additional, Küppers, Michael, additional, Lara, Luisa M., additional, Lazzarin, Monica, additional, Marzari, Francesco, additional, Lopez Moreno, Josè J., additional, Naletto, Giampiero, additional, Oklay, Nilda, additional, Shi, Xian, additional, Thomas, Nicolas, additional, Tubiana, Cecilia, additional, and Vincent, Jean-Baptiste, additional

Published
2016
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19. Aswan site on comet 67P/Churyumov-Gerasimenko: Morphology, boulder evolution, and spectrophotometry

Author

Pajola, Maurizio, primary, Oklay, Nilda, additional, La Forgia, Fiorangela, additional, Giacomini, Lorenza, additional, Massironi, Matteo, additional, Bertini, Ivano, additional, El-Maarry, M. R., additional, Marzari, Francesco, additional, Preusker, Frank, additional, Scholten, Frank, additional, Höfner, Sebastian, additional, Lee, Jui-Chi, additional, Vincent, Jean-Baptiste, additional, Groussin, Olivier, additional, Naletto, Giampiero, additional, Lazzarin, Monica, additional, Barbieri, Cesare, additional, Sierks, Holger, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst U., additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria A., additional, Bertaux, Jean-Loup, additional, Cremonese, Gabriele, additional, Deppo, Vania Da, additional, Davidsson, Björn, additional, De Cecco, Mariolino, additional, Debei, Stefano, additional, Ferri, Francesca, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Güttler, Carsten, additional, Gutierrez, Pedro J., additional, Hviid, Stubbe F., additional, Ip, Wing-Huen, additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kramm, J.-Rainer, additional, Küppers, Michael, additional, Kürt, Ekkehard, additional, Lara, Luisa M., additional, Lin, Zhong-Yi, additional, Lopez Moreno, Jose J., additional, Magrin, Sara, additional, Michalik, Harald, additional, Mottola, Stefano, additional, Thomas, Nicholas, additional, and Tubiana, Cecilia, additional

Published
2016
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20. The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m

Author

Pajola, Maurizio, primary, Lucchetti, Alice, additional, Vincent, Jean-Baptiste, additional, Oklay, Nilda, additional, El-Maarry, Mohamed R., additional, Bertini, Ivano, additional, Naletto, Giampiero, additional, Lazzarin, Monica, additional, Massironi, Matteo, additional, Sierks, Holger, additional, Barbieri, Cesare, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst U., additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria A., additional, Bertaux, Jean-Loup, additional, Boudreault, Steve, additional, Cremonese, Gabriele, additional, Deppo, Vania Da, additional, Davidsson, Björn, additional, Debei, Stefano, additional, De Cecco, Mariolino, additional, Deller, Jakob, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Gicquel, Adeline, additional, Groussin, Olivier, additional, Gutierrez, Pedro J., additional, Güttler, Carsten, additional, Hofmann, Marc, additional, Höfner, Sebastian, additional, Hviid, Stubbe F., additional, Ip, Wing-Huen, additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kramm, J.-Rainer, additional, Kührt, Ekkehard, additional, Küppers, Michael, additional, La Forgia, Fiorangela, additional, Lara, Luisa M., additional, Lee, Jui-Chi, additional, Lin, Zhong-Yi, additional, Lopez Moreno, Jose J., additional, Marzari, Francesco, additional, Michalik, Harald, additional, Mottola, Stefano, additional, Preusker, Frank, additional, Scholten, Frank, additional, Thomas, Nicholas, additional, Toth, Imre, additional, and Tubiana, Cecilia, additional

Published
2016
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21. Size-frequency distribution of boulders >= 7 m on comet 67P/Churyumov-Gerasimenko

Author

Pajola, Maurizio, Vincent, Jean-Baptiste, Guettler, Carsten, Lee, Jui-Chi, Bertini, Ivano, Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Giacomini, Lorenza, Lucchetti, Alice, Barbieri, Cesare, Cremonese, Gabriele, Naletto, Giampiero, Pommerol, Antoine, El-Maarry, Mohamed R., Besse, Sebastien, Kueppers, Michael, La Forgia, Fiorangela, Lazzarin, Monica, Thomas, Nicholas, Auger, Anne-Therese, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Lopez Moreno, Jose J., Magrin, Sara, Marchi, Simone, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Oklay, Nilda, Preusker, Frank, Scholten, Frank, Tubiana, Cecilia, Pajola, Maurizio, Vincent, Jean-Baptiste, Guettler, Carsten, Lee, Jui-Chi, Bertini, Ivano, Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Giacomini, Lorenza, Lucchetti, Alice, Barbieri, Cesare, Cremonese, Gabriele, Naletto, Giampiero, Pommerol, Antoine, El-Maarry, Mohamed R., Besse, Sebastien, Kueppers, Michael, La Forgia, Fiorangela, Lazzarin, Monica, Thomas, Nicholas, Auger, Anne-Therese, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Lopez Moreno, Jose J., Magrin, Sara, Marchi, Simone, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Oklay, Nilda, Preusker, Frank, Scholten, Frank, and Tubiana, Cecilia

Abstract

Aims. We derive for the first time the size-frequency distribution of boulders on a comet, 67P/Churyumov-Gerasimenko (67P), computed from the images taken by the Rosetta/OSIRIS imaging system. We highlight the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera, NAC. on 5 and 6 August 2014. The scale of these images (2.44-2.03 m/px) is such that boulders >= 7 m can be identified and manually extracted from the datasets with the software ArcGIS. We derived both global and localized size-frequency distributions. The three-pixel sampling detection, coupled with the favorable shadowine of the surface (observation phase angle ranging from 48 to 53), enables unequivocally detecting boulders scattered all over the illuminated side of 67P. Results. We identify 3546 boulders larger than 7 m on the imaged surface (36.4 km(2)), with a global number density of nearly 100/km(2) and a cumulative size-frequency distribution represented by a power-law with index of -3.6 +0.2/-0.3. The two lobes of 67P appear to have slightly different distributions, with an index of -3.5 +0.2/-0.3 for the main lobe (body) and -4.0 +0.31-0.2 for the small lobe (head). The steeper distribution of the small lobe might be due to a more pervasive fracturing. The difference of the distribution for the connecting region (neck) is much more significant, with an index value of -2.2 +0.2/-0.2. We propose that the boulder field located in the neck area is the result of blocks falling from the contiguous Hathor cliff. The lower slope of the size-frequency distribution we see today in the neck area might be due to the concurrent processes acting on the smallest boulders, such as i) disintegration or fragmentation and vanishing through sublimation; ii) uplifting by gas drag and consequent redistribution; and iii) burial beneath a debris blanket. We also derived the cumulative size-frequency distribution per km(2) of loca

Published
2015
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22. Size-frequency distribution of boulders ≥7 m on comet 67P/Churyumov-Gerasimenko

Author

Pajola, Maurizio, primary, Vincent, Jean-Baptiste, additional, Güttler, Carsten, additional, Lee, Jui-Chi, additional, Bertini, Ivano, additional, Massironi, Matteo, additional, Simioni, Emanuele, additional, Marzari, Francesco, additional, Giacomini, Lorenza, additional, Lucchetti, Alice, additional, Barbieri, Cesare, additional, Cremonese, Gabriele, additional, Naletto, Giampiero, additional, Pommerol, Antoine, additional, El-Maarry, Mohamed R., additional, Besse, Sébastien, additional, Küppers, Michael, additional, La Forgia, Fiorangela, additional, Lazzarin, Monica, additional, Thomas, Nicholas, additional, Auger, Anne-Thérèse, additional, Sierks, Holger, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst U., additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria A., additional, Bertaux, Jean-Loup, additional, Deppo, Vania Da, additional, Davidsson, Björn, additional, De Cecco, Mariolino, additional, Debei, Stefano, additional, Ferri, Francesca, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Groussin, Olivier, additional, Gutierrez, Pedro J., additional, Hviid, Stubbe F., additional, Ip, Wing-Huen, additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kramm, J.-Rainer, additional, Kürt, Ekkehard, additional, Lara, Luisa M., additional, Lin, Zhong-Yi, additional, Moreno, Jose J. Lopez, additional, Magrin, Sara, additional, Marchi, Simone, additional, Michalik, Harald, additional, Moissl, Richard, additional, Mottola, Stefano, additional, Oklay, Nilda, additional, Preusker, Frank, additional, Scholten, Frank, additional, and Tubiana, Cecilia, additional

Published
2015
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26. Size-frequency distribution of boulders ≥7 m on comet 67P/Churyumov-Gerasimenko

Author

Da Deppo, Vania, Ip, Wing-Huen, Marzari, Francesco, Scholten, Frank, Preusker, Frank, Besse, Sebastien, Guettler, Carsten, Mottola, Stefano, Barucci, Maria A., Davidsson, Bjoern, De Cecco, Mariolino, Kuert, Ekkehard, La Forgia, Fiorangela, Lopez Moreno, Jose J., Fornasier, Sonia, Hviid, Stubbe F., Cremonese, Gabriele, Lee, Jui-Chi, Bertini, Ivano, Kueppers, Michael, Lazzarin, Monica, Gutierrez, Pedro J., Ferri, Francesca, Lamy, Philippe, Thomas, Nicholas, Lara, Luisa M., Massironi, Matteo, Koschny, Detlef, Auger, Anne-Therese, Vincent, Jean-Baptiste, Knollenberg, Joerg, Debei, Stefano, Groussin, Olivier, Fulle, Marco, Jorda, Laurent, Magrin, Sara, Oklay, Nilda, Bertaux, Jean-Loup, Sierks, Holger, Elmaarry, Mohamed Ramy, Kramm, J. Rainer, Barbieri, Cesare, Keller, Horst U., A'Hearn, Michael F., Pajola, Maurizio, Marchi, Simone, Simioni, Emanuele, Giacomini, Lorenza, Pommerol, Antoine, Tubiana, Cecilia, Lucchetti, Alice, Rickman, Hans, Naletto, Giampiero, Lin, Zhong-Yi, Agarwal, Jessica, Moissl, Richard, Rodrigo, Rafael, and Michalik, Harald

Subjects
13. Climate action, 530 Physics, 500 Science
Abstract

Aims. We derive for the first time the size-frequency distribution of boulders on a comet, 67P/Churyumov-Gerasimenko (67P), computed from the images taken by the Rosetta/OSIRIS imaging system. We highlight the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera, NAC, on 5 and 6 August 2014. The scale of these images (2.44−2.03 m/px) is such that boulders ≥7 m can be identified and manually extracted from the datasets with the software ArcGIS. We derived both global and localized size-frequency distributions. The three-pixel sampling detection, coupled with the favorable shadowing of the surface (observation phase angle ranging from 48° to 53°), enables unequivocally detecting boulders scattered all over the illuminated side of 67P. Results. We identify 3546 boulders larger than 7 m on the imaged surface (36.4 km2), with a global number density of nearly 100/km2 and a cumulative size-frequency distribution represented by a power-law with index of −3.6 +0.2/−0.3. The two lobes of 67P appear to have slightly different distributions, with an index of −3.5 +0.2/−0.3 for the main lobe (body) and −4.0 +0.3/−0.2 for the small lobe (head). The steeper distribution of the small lobe might be due to a more pervasive fracturing. The difference of the distribution for the connecting region (neck) is much more significant, with an index value of −2.2 +0.2/−0.2. We propose that the boulder field located in the neck area is the result of blocks falling from the contiguous Hathor cliff. The lower slope of the size-frequency distribution we see today in the neck area might be due to the concurrent processes acting on the smallest boulders, such as i) disintegration or fragmentation and vanishing through sublimation; ii) uplifting by gas drag and consequent redistribution; and iii) burial beneath a debris blanket. We also derived the cumulative size-frequency distribution per km2 of localized areas on 67P. By comparing the cumulative size-frequency distributions of similar geomorphological settings, we derived similar power-law index values. This suggests that despite the selected locations on different and often opposite sides of the comet, similar sublimation or activity processes, pit formation or collapses, as well as thermal stresses or fracturing events occurred on multiple areas of the comet, shaping its surface into the appearance we see today.

27. The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m

Author

La Forgia, Fiorangela, Hofmann, Marc, Fulle, Marco, Keller, Horst U., Toth, Imre, Agarwal, Jessica, Groussin, Olivier, Lopez Moreno, Jose J., De Cecco, Mariolino, Michalik, Harald, Gutierrez, Pedro J., Höfner, Sebastian, Vincent, Jean-Baptiste, Gicquel, Adeline, Naletto, Giampiero, Fornasier, Sonia, Deppo, Vania Da, Rickman, Hans, Elmaarry, Mohamed Ramy, Koschny, Detlef, Massironi, Matteo, Barucci, Maria A., Thomas, Nicolas, Kramm, J.-Rainer, Scholten, Frank, Bertaux, Jean-Loup, Lara, Luisa M., Lin, Zhong-Yi, Kührt, Ekkehard, Bertini, Ivano, Lamy, Philippe, Mottola, Stefano, Sierks, Holger, Lazzarin, Monica, Lee, Jui-Chi, Oklay, Nilda, Jorda, Laurent, Hviid, Stubbe F., Cremonese, Gabriele, Marzari, Francesco, Debei, Stefano, Pajola, Maurizio, Lucchetti, Alice, Davidsson, Björn, Tubiana, Cecilia, Küppers, Michael, Preusker, Frank, Ip, Wing-Huen, Güttler, Carsten, Boudreault, Steve, Rodrigo, Rafael, Barbieri, Cesare, Knollenberg, Jörg, A’Hearn, Michael F., and Deller, Jakob

Subjects
13. Climate action, 530 Physics, 520 Astronomy, 620 Engineering
Abstract

Aims. We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 2 May 2015 at a distance of 125 km from the nucleus. The scale of this dataset is 2.3 m/px; the high resolution of the images, coupled with the favorable observation phase angle of 62 degrees, provided the possibility to unambiguously identify boulders ≥ 7 m on the surface of 67P and to manually extract them with the software ArcGIS. We derived the size-frequency distribution of the illuminated southern hemisphere. Results. We found a power-law index of -3.6 + 0.2 for the boulders on the southern hemisphere with a diameter range of 7-35 m. The power-law index is equal to the one previously found on northern and equatorial regions of 67P, suggesting that similar boulder formation processes occur in both hemispheres. The power-law index is related to gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. In addition, the presence of a larger number of boulders per km² in the southern hemisphere, which is a factor of 3 higher with respect to the northern hemisphere, suggests that the southernmost terrains of 67P are affected by a stronger thermal fracturing and sublimating activity, hence possibly causing larger regressive erosion and gravitational events.

28. Growth of ZnO Single Crystals by Annealing Sol–Gel-derived Films with PDMS Pre-pressing

Author

Lee, Jui-Chi, Leu, Ing-Chi, and Hon, Min-Hsiung

Abstract

We demonstrate a simple and novel approach for the low-temperature (400 °C) solid-state growth of ZnO micro- and nanorods directly from sol–gel-derived Al-doped ZnO films on silicon substrates without any catalyst. Hot pressing the films by a PDMS pad before annealing has been found to be effective for the creation of ZnO rods. A possible nucleation mechanism of ZnO rods has also been proposed.

Published
2008
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