ALBERT

Description: 252 transient drops in atmospheric pressure, likely caused by passing convective vortices, were detected by the REMS instrument during the first Martian year of the Mars Science Laboratory (MSL) landed mission. These events resembled the vortex signatures detected by the previous Mars landers Pathfinder and Phoenix, however the MSL observations contained fewer pressure drops greater than 1.5 Pa and none greater than 3.0 Pa. Apparently these vortices were generally not lifting dust since only one probable dust devil has been observed visually by MSL [Moores et al., 2015]. Since ample dust seems to be present on the surface [Arvidson et al., 2014], the obvious explanation for this is the smaller number of strong vortices with large central pressure drops. The annual variation in the number of detected convective vortices followed approximately the variation in Dust Devil Activity (DDA) predicted by the MarsWRF numerical climate model. This result does not prove, however, that the amount of dust lifted by dust devils would depend linearly on DDA, as is assumed in several numerical models of the Martian atmosphere, since dust devils are only the most intense fraction of all convective vortices on Mars, and the amount of dust that can be lifted by a dust devil depends on its central pressure drop. Sol-to-sol variations in the number of vortices were usually small. However, on one sol a sudden increase in vortex activity, related to a dust storm front, was detected.

Description: Key Points A microwave oven method achieved solubilization of silicate rock powders in up to 4 h. The digestion conditions inhibit the precipitation of fluorides. Recoveries of investigated trace elements were mostly satisfactory, but a few specific exceptions require further investigation. The complete dissolution of representative test portions of powdered rock samples for the determination of the mass fractions of trace elements by ICP‐MS relies either on aggressive and time‐consuming acid digestions or fusion/sintering with appropriate fluxes. Here, we evaluate a microwave oven dissolution method that employs a solution of NH4HF2 and HNO3. The entire procedure occurs in a closed vessel system and takes up to 4 h. In hundreds of digestions, the precipitation of fluorides was never observed. Replicate decomposition of 100 mg of twenty‐one international reference materials (RMs) of igneous rocks, and also one of a shale presented mostly satisfactory recoveries of forty‐one trace elements. Important exceptions were Zr and Hf in G‐2 and GSP‐2 (mean recoveries of ca. 70%), although for four other felsic rock RMs, the digestion was complete. For ultramafic rock RMs, we present Cr results that indicate quantitative dissolution of Cr‐bearing phases. We discuss the findings and conclude that advances in sample preparation of geological materials for instrumental analysis would benefit from a better understanding of how specific characteristics, such as composition and crystallinity of certain minerals, may affect their reactivity.

Description: Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and (18)O/(16)O in water and (13)C/(12)C, (18)O/(16)O, (17)O/(16)O, and (13)C(18)O/(12)C(16)O in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Webster, Chris R -- Mahaffy, Paul R -- Flesch, Gregory J -- Niles, Paul B -- Jones, John H -- Leshin, Laurie A -- Atreya, Sushil K -- Stern, Jennifer C -- Christensen, Lance E -- Owen, Tobias -- Franz, Heather -- Pepin, Robert O -- Steele, Andrew -- MSL Science Team -- Achilles, Cherie -- Agard, Christophe -- Alves Verdasca, Jose Alexandre -- Anderson, Robert -- Anderson, Ryan -- Archer, Doug -- Armiens-Aparicio, Carlos -- Arvidson, Ray -- Atlaskin, Evgeny -- Aubrey, Andrew -- Baker, Burt -- Baker, Michael -- Balic-Zunic, Tonci -- Baratoux, David -- Baroukh, Julien -- Barraclough, Bruce -- Bean, Keri -- Beegle, Luther -- Behar, Alberto -- Bell, James -- Bender, Steve -- Benna, Mehdi -- Bentz, Jennifer -- Berger, Gilles -- Berger, Jeff -- Berman, Daniel -- Bish, David -- Blake, David F -- Blanco Avalos, Juan J -- Blaney, Diana -- Blank, Jen -- Blau, Hannah -- Bleacher, Lora -- Boehm, Eckart -- Botta, Oliver -- Bottcher, Stephan -- Boucher, Thomas -- Bower, Hannah -- Boyd, Nick -- Boynton, Bill -- Breves, Elly -- Bridges, John -- Bridges, Nathan -- Brinckerhoff, William -- Brinza, David -- Bristow, Thomas -- Brunet, Claude -- Brunner, Anna -- Brunner, Will -- Buch, Arnaud -- Bullock, Mark -- Burmeister, Sonke -- Cabane, Michel -- Calef, Fred -- Cameron, James -- Campbell, John -- Cantor, Bruce -- Caplinger, Michael -- Caride Rodriguez, Javier -- Carmosino, Marco -- Carrasco Blazquez, Isaias -- Charpentier, Antoine -- Chipera, Steve -- Choi, David -- Clark, Benton -- Clegg, Sam -- Cleghorn, Timothy -- Cloutis, Ed -- Cody, George -- Coll, Patrice -- Conrad, Pamela -- Coscia, David -- Cousin, Agnes -- Cremers, David -- Crisp, Joy -- Cros, Alain -- Cucinotta, Frank -- d'Uston, Claude -- Davis, Scott -- Day, Mackenzie -- de la Torre Juarez, Manuel -- DeFlores, Lauren -- DeLapp, Dorothea -- DeMarines, Julia -- DesMarais, David -- Dietrich, William -- Dingler, Robert -- Donny, Christophe -- Downs, Bob -- Drake, Darrell -- Dromart, Gilles -- Dupont, Audrey -- Duston, Brian -- Dworkin, Jason -- Dyar, M Darby -- Edgar, Lauren -- Edgett, Kenneth -- Edwards, Christopher -- Edwards, Laurence -- Ehlmann, Bethany -- Ehresmann, Bent -- Eigenbrode, Jen -- Elliott, Beverley -- Elliott, Harvey -- Ewing, Ryan -- Fabre, Cecile -- Fairen, Alberto -- Farley, Ken -- Farmer, Jack -- Fassett, Caleb -- Favot, Laurent -- Fay, Donald -- Fedosov, Fedor -- Feldman, Jason -- Feldman, Sabrina -- Fisk, Marty -- Fitzgibbon, Mike -- Floyd, Melissa -- Fluckiger, Lorenzo -- Forni, Olivier -- Fraeman, Abby -- Francis, Raymond -- Francois, Pascaline -- Freissinet, Caroline -- French, Katherine Louise -- Frydenvang, Jens -- Gaboriaud, Alain -- Gailhanou, Marc -- Garvin, James -- Gasnault, Olivier -- Geffroy, Claude -- Gellert, Ralf -- Genzer, Maria -- Glavin, Daniel -- Godber, Austin -- Goesmann, Fred -- Goetz, Walter -- Golovin, Dmitry -- Gomez Gomez, Felipe -- Gomez-Elvira, Javier -- Gondet, Brigitte -- Gordon, Suzanne -- Gorevan, Stephen -- Grant, John -- Griffes, Jennifer -- Grinspoon, David -- Grotzinger, John -- Guillemot, Philippe -- Guo, Jingnan -- Gupta, Sanjeev -- Guzewich, Scott -- Haberle, Robert -- Halleaux, Douglas -- Hallet, Bernard -- Hamilton, Vicky -- Hardgrove, Craig -- Harker, David -- Harpold, Daniel -- Harri, Ari-Matti -- Harshman, Karl -- Hassler, Donald -- Haukka, Harri -- Hayes, Alex -- Herkenhoff, Ken -- Herrera, Paul -- Hettrich, Sebastian -- Heydari, Ezat -- Hipkin, Victoria -- Hoehler, Tori -- Hollingsworth, Jeff -- Hudgins, Judy -- Huntress, Wesley -- Hurowitz, Joel -- Hviid, Stubbe -- Iagnemma, Karl -- Indyk, Steve -- Israel, Guy -- Jackson, Ryan -- Jacob, Samantha -- Jakosky, Bruce -- Jensen, Elsa -- Jensen, Jaqueline Klovgaard -- Johnson, Jeffrey -- Johnson, Micah -- Johnstone, Steve -- Jones, Andrea -- Joseph, Jonathan -- Jun, Insoo -- Kah, Linda -- Kahanpaa, Henrik -- Kahre, Melinda -- Karpushkina, Natalya -- Kasprzak, Wayne -- Kauhanen, Janne -- Keely, Leslie -- Kemppinen, Osku -- Keymeulen, Didier -- Kim, Myung-Hee -- Kinch, Kjartan -- King, Penny -- Kirkland, Laurel -- Kocurek, Gary -- Koefoed, Asmus -- Kohler, Jan -- Kortmann, Onno -- Kozyrev, Alexander -- Krezoski, Jill -- Krysak, Daniel -- Kuzmin, Ruslan -- Lacour, Jean Luc -- Lafaille, Vivian -- Langevin, Yves -- Lanza, Nina -- Lasue, Jeremie -- Le Mouelic, Stephane -- Lee, Ella Mae -- Lee, Qiu-Mei -- Lees, David -- Lefavor, Matthew -- Lemmon, Mark -- Lepinette Malvitte, Alain -- Leveille, Richard -- Lewin-Carpintier, Eric -- Lewis, Kevin -- Li, Shuai -- Lipkaman, Leslie -- Little, Cynthia -- Litvak, Maxim -- Lorigny, Eric -- Lugmair, Guenter -- Lundberg, Angela -- Lyness, Eric -- Madsen, Morten -- Maki, Justin -- Malakhov, Alexey -- Malespin, Charles -- Malin, Michael -- Mangold, Nicolas -- Manhes, Gerard -- Manning, Heidi -- Marchand, Genevieve -- Marin Jimenez, Mercedes -- Martin Garcia, Cesar -- Martin, Dave -- Martin, Mildred -- Martinez-Frias, Jesus -- Martin-Soler, Javier -- Martin-Torres, F Javier -- Mauchien, Patrick -- Maurice, Sylvestre -- McAdam, Amy -- McCartney, Elaina -- McConnochie, Timothy -- McCullough, Emily -- McEwan, Ian -- McKay, Christopher -- McLennan, Scott -- McNair, Sean -- Melikechi, Noureddine -- Meslin, Pierre-Yves -- Meyer, Michael -- Mezzacappa, Alissa -- Miller, Hayden -- Miller, Kristen -- Milliken, Ralph -- Ming, Douglas -- Minitti, Michelle -- Mischna, Michael -- Mitrofanov, Igor -- Moersch, Jeff -- Mokrousov, Maxim -- Molina Jurado, Antonio -- Moores, John -- Mora-Sotomayor, Luis -- Morookian, John Michael -- Morris, Richard -- Morrison, Shaunna -- Mueller-Mellin, Reinhold -- Muller, Jan-Peter -- Munoz Caro, Guillermo -- Nachon, Marion -- Navarro Lopez, Sara -- Navarro-Gonzalez, Rafael -- Nealson, Kenneth -- Nefian, Ara -- Nelson, Tony -- Newcombe, Megan -- Newman, Claire -- Newsom, Horton -- Nikiforov, Sergey -- Nixon, Brian -- Noe Dobrea, Eldar -- Nolan, Thomas -- Oehler, Dorothy -- Ollila, Ann -- Olson, Timothy -- de Pablo Hernandez, Miguel Angel -- Paillet, Alexis -- Pallier, Etienne -- Palucis, Marisa -- Parker, Timothy -- Parot, Yann -- Patel, Kiran -- Paton, Mark -- Paulsen, Gale -- Pavlov, Alex -- Pavri, Betina -- Peinado-Gonzalez, Veronica -- Peret, Laurent -- Perez, Rene -- Perrett, Glynis -- Peterson, Joe -- Pilorget, Cedric -- Pinet, Patrick -- Pla-Garcia, Jorge -- Plante, Ianik -- Poitrasson, Franck -- Polkko, Jouni -- Popa, Radu -- Posiolova, Liliya -- Posner, Arik -- Pradler, Irina -- Prats, Benito -- Prokhorov, Vasily -- Purdy, Sharon Wilson -- Raaen, Eric -- Radziemski, Leon -- Rafkin, Scot -- Ramos, Miguel -- Rampe, Elizabeth -- Raulin, Francois -- Ravine, Michael -- Reitz, Gunther -- Renno, Nilton -- Rice, Melissa -- Richardson, Mark -- Robert, Francois -- Robertson, Kevin -- Rodriguez Manfredi, Jose Antonio -- Romeral-Planello, Julio J -- Rowland, Scott -- Rubin, David -- Saccoccio, Muriel -- Salamon, Andrew -- Sandoval, Jennifer -- Sanin, Anton -- Sans Fuentes, Sara Alejandra -- Saper, Lee -- Sarrazin, Philippe -- Sautter, Violaine -- Savijarvi, Hannu -- Schieber, Juergen -- Schmidt, Mariek -- Schmidt, Walter -- Scholes, Daniel -- Schoppers, Marcel -- Schroder, Susanne -- Schwenzer, Susanne -- Sebastian Martinez, Eduardo -- Sengstacken, Aaron -- Shterts, Ruslan -- Siebach, Kirsten -- Siili, Tero -- Simmonds, Jeff -- Sirven, Jean-Baptiste -- Slavney, Susie -- Sletten, Ronald -- Smith, Michael -- Sobron Sanchez, Pablo -- Spanovich, Nicole -- Spray, John -- Squyres, Steven -- Stack, Katie -- Stalport, Fabien -- Stein, Thomas -- Stewart, Noel -- Stipp, Susan Louise Svane -- Stoiber, Kevin -- Stolper, Ed -- Sucharski, Bob -- Sullivan, Rob -- Summons, Roger -- Sumner, Dawn -- Sun, Vivian -- Supulver, Kimberley -- Sutter, Brad -- Szopa, Cyril -- Tan, Florence -- Tate, Christopher -- Teinturier, Samuel -- ten Kate, Inge -- Thomas, Peter -- Thompson, Lucy -- Tokar, Robert -- Toplis, Mike -- Torres Redondo, Josefina -- Trainer, Melissa -- Treiman, Allan -- Tretyakov, Vladislav -- Urqui-O'Callaghan, Roser -- Van Beek, Jason -- Van Beek, Tessa -- VanBommel, Scott -- Vaniman, David -- Varenikov, Alexey -- Vasavada, Ashwin -- Vasconcelos, Paulo -- Vicenzi, Edward -- Vostrukhin, Andrey -- Voytek, Mary -- Wadhwa, Meenakshi -- Ward, Jennifer -- Weigle, Eddie -- Wellington, Danika -- Westall, Frances -- Wiens, Roger Craig -- Wilhelm, Mary Beth -- Williams, Amy -- Williams, Joshua -- Williams, Rebecca -- Williams, Richard B -- Wilson, Mike -- Wimmer-Schweingruber, Robert -- Wolff, Mike -- Wong, Mike -- Wray, James -- Wu, Megan -- Yana, Charles -- Yen, Albert -- Yingst, Aileen -- Zeitlin, Cary -- Zimdar, Robert -- Zorzano Mier, Maria-Paz -- New York, N.Y. -- Science. 2013 Jul 19;341(6143):260-3. doi: 10.1126/science.1237961.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. chris.r.webster@jpl.nasa.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23869013" target="_blank"〉PubMed〈/a〉

Description: The first in situ investigation of an active dune field on another planetary surface occurred in 2015-2016 when the MSL Curiosity rover investigated the Bagnold Dunes on Mars. HIRISE images show clear seasonal variations that are in good agreement with atmospheric model predictions of intra-annual sand flux and migration directions that together indicate that the campaign occurred during a period of low wind activity. Curiosity surface images show that limited changes nevertheless occurred, with movement of large grains, particularly on freshly exposed surfaces, two occurrences of secondary grain flow on the slip face of Namib Dune, and a slump on a freshly exposed surface of a large ripple. These changes are seen at sol-to-sol time scales. Grains on a rippled sand deposit and unconsolidated dump piles show limited movement of large grains over a few hours during which mean friction speeds are estimated at 0.3 - 0.4 m s -1 . Overall, the correlation between changes and peak REMS winds is moderate, with high wind events associated with changes in some cases, but not in others, suggesting that other factors are also at work. The distribution of REMS 1 Hz wind speeds show a tail up to the 20 m s -1 , showing that even higher speed winds occur. Non-aeolian triggering mechanisms are also possible. The low activity period at the dunes documented by Curiosity provides clues to processes that dominated in the Martian past under conditions of lower obliquity.

Description: We have developed a chemical mechanism describing the tropospheric degradation of chlorine-containing very short-lived substances (VSLS). The scheme was included in a global atmospheric model and used to quantify the stratospheric injection of chlorine from anthropogenic VSLS ( ) between 2005 to 2013. By constraining the model with surface measurements of chloroform (CHCl 3 ), dichloromethane (CH 2 Cl 2 ), tetrachloroethene (C 2 Cl 4 ), trichloroethene (C 2 HCL 3 ) and 1,2-dichloroethane (CH 2 ClCH 2 Cl), we infer a 2013 mixing ratio of 123 parts per trillion (ppt). Stratospheric injection of source gases dominates this supply, accounting for ~83% of the total. The remainder comes from VSLS-derived organic products, phosgene (COCl 2 , 7%) and formyl chloride (CHClO, 2%), and also hydrogen chloride (HCl, 8%). Stratospheric increased by ~52% between 2005-2013, with a mean growth rate of 3.7 ppt Cl/yr. This increase is due to recent and ongoing growth in anthropogenic CH – the most abundant chlorinated VSLS not controlled by the Montreal Protocol.

Description: We investigated the millennial variability (1000 AD-2000 AD) of global Biogenic Volatile Organic Compound (BVOC) emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene and sesquiterpene and Lund-Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission trends were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have significant short-term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr −1 (13% and 19% less than during 1750–1850 and 1000–1200, respectively) and LPJ-GUESS emissions were 323 TgC yr −1 (15% and 20% less than during 1750–1850 and 1000–1200, respectively). Monoterpene emissions were 89 TgC yr −1 (10% and 6% higher than during 1750–1850 and 1000–1200, respectively) in MEGAN, and 24 TgC yr −1 (2% higher and 5% less thanduring 1750–1850 and 1000–1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr −1 (10% and 4% higher than during 1750–1850 and 1000–1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.