ALBERT

Description: Sources and Transformations of Anthropogenic Nitrogen along an Urban River-Estuarine Continuum Michael J. Pennino, Sujay S. Kaushal, Sudhir Murthy, Joel Blomquist, Jeff Cornwell, and Lora Harris Biogeosciences Discuss., doi:10.5194/bg-2016-264,2016 Manuscript under review for BG (discussion: open, 0 comments) The results of this manuscript report the analysis of the fate and transport of wastewater and anthropogenic nitrogen along the Potomac River Estuary, from Washington D.C. to the Chesapeake Bay. In conjunction with a mass balance approach, nitrate isotopes were used to estimate fluxes and trace the sources and transformations N along the estuary. This study shows that estuaries have a large capacity to transform N inputs, but with large seasonal variability due to hydrological extremes.

Description: Boreal fire records in Northern Hemisphere ice cores: A review Michel Legrand, Joseph McConnell, Hubertus Fischer, Eric W. Wolff, Susanne Preunkert, Nathan Chellman, Daiana Leuenberger, Olivia Maselli, Michael Sigl, Simon Schüpbach, and Mike Flannigan Clim. Past Discuss., doi:10.5194/cp-2016-70,2016 Manuscript under review for CP (discussion: open, 0 comments) Here we review previous attempts made to reconstruct past forest fire using chemical signals recorded in Greenland ice. We showed that the Greenland ice records of ammonium, found to be a good fire proxy, consistently indicate changing fire activity in Canada in response to past climatic conditions that occurred since the last 15 000 years including the little ice age and the last large climatic transition.

Description: Tectonothermal evolution in the core of an arcuate fold and thrust belt: the south-eastern sector of the Cantabrian Zone (Variscan belt, north-western Spain) María Luz Valín, Susana García-López, Covadonga Brime, Fernando Bastida, and Jesús Aller Solid Earth, 7, 1003-1022, doi:10.5194/se-7-1003-2016, 2016 The tectonothermal evolution of an area located in the core of the Ibero-Armorican Arc (Variscan belt) has been determined by using the conodont colour alteration index (CAI), Kübler index of illite (KI), the Árkai index of chlorite (AI) and the analysis of clay minerals and rock cleavage. The area is part of the Cantabrian Zone (CZ), which represents the foreland fold and thrust belt of the orogen. It has been thrust by several large units of the CZ, what resulted in the generation of a large number of synorogenic Carboniferous sediments. CAI, KI and AI values show an irregular distribution of metamorphic grade, independent of stratigraphic position. Two tectonothermal events have been distinguished in the area. The first one, poorly defined, is mainly located in the northern part. It gave rise to very-low-grade metamorphism in some areas and it was associated with a deformation event that resulted in the emplacement of the last large thrust unit and development of upright folds and associated cleavage ( S 1 ). The second tectonothermal event gave rise to low-grade metamorphism and cleavage ( S 2 ) crosscutting earlier upright folds in the central, western and southern parts of the study area. The event continued with the intrusion of small igneous rock bodies, which gave rise to contact metamorphism and hydrothermal alteration. This event was linked to an extensional episode due to a gravitational instability at the end of the Variscan deformation. This tectonothermal evolution occurred during the Gzhelian–Sakmarian. Subsequently, several hydrothermal episodes took place and local crenulation cleavage developed during the Alpine deformation.

Description: Microstructures and deformation mechanisms in Opalinus Clay: insights from scaly clay from the Main Fault in the Mont Terri Rock Laboratory (CH) Ben Laurich, Janos L. Urai, and Christophe Nussbaum Solid Earth Discuss., doi:10.5194/se-2016-94,2016 Manuscript under review for SE (discussion: open, 0 comments) Scaly clay is a well-known rock fabric that can develop in tectonic systems and that can alter the physical rock properties of a formation. However, internal microstructure and evolution of this fabric remains poorly understood. We examined the scaly microstructure of progressively faulted Opalinus Clay using optical as well as scanning electron microscopy. We present an evolutionary model for scaly clay that is of interest in the evaluation of Opalinus Clay to host radioactive waste.

Description: Microstructures and deformation mechanisms in Opalinus Clay: insights from scaly clay from the Main Fault in the Mont Terri Rock Laboratory (CH) Ben Laurich, Janos L. Urai, and Christophe Nussbaum Solid Earth Discuss., doi:10.5194/se-2016-94,2016 Manuscript under review for SE (discussion: open, 0 comments) Scaly clay is a well-known rock fabric that can develop in tectonic systems and that can alter the physical rock properties of a formation. However, internal microstructure and evolution of this fabric remains poorly understood. We examined the scaly microstructure of progressively faulted Opalinus Clay using optical as well as scanning electron microscopy. We present an evolutionary model for scaly clay that is of interest in the evaluation of Opalinus Clay to host radioactive waste.

Description: Fixation kinetics of chelated and non-chelated zinc in semi-arid alkaline soils: application to zinc management Theophilus K. Udeigwe, Madeleine Eichmann, and Matthew C. Menkiti Solid Earth, 7, 1023-1031, doi:10.5194/se-7-1023-2016, 2016 Micronutrient fixation leads to the reduction of plant-available portions. This study examined the fixation kinetics of chelated and non-chelated zinc (Zn) in semi-arid soils. About 30 % more Zn was fixed in the non-chelated system in the first 14 days. Slope of change of Zn to Cu (i.e., Cu–Zn) was higher than other micronutrients. Zn fixation kinetics were better described by a power-function model. Tools developed from this study will be used to advance micronutrient management.

Description: Improved MODIS Dark Target Aerosol Optical Depth algorithm over land: Angular effect Correction Yerong Wu, Martin de Graaf, and Massimo Menenti Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-185,2016 Manuscript under review for AMT (discussion: open, 0 comments) In this paper, we developed a new algorithm to improve the retrieval of Aerosol Optical Depth (AOD) over land with satellite measurement, by refining the shape of the spectral surface reflectance to improve the estimated background reflectance in the channel used for AOD retrieval. The results show that the angular effects of the retrievals are largely reduced, including fewer occurrences of negative retrievals. This implies that the users can get more accurate data without angular bias.

Description: Investigation of processes controlling summertime gaseous elemental mercury oxidation at midlatitudinal marine, coastal, and inland sites Zhuyun Ye, Huiting Mao, Che-Jen Lin, and Su Youn Kim Atmos. Chem. Phys., 16, 8461-8478, doi:10.5194/acp-16-8461-2016, 2016 In this study, a state-of-the-art chemical mechanism was incorporated into a box model to investigate the atmospheric Hg cycling in different environments. As a result, for each of the three environments, GOM diurnal cycles of over half the selected cases were reasonably represented by the box model. A realistic model can be a powerful tool, providing important information on atmospheric Hg cycling and implications for policy makers.

Description: Effects of polar stratospheric clouds in the Nimbus 7 LIMS Version 6 data set Ellis Remsberg and V. Lynn Harvey Atmos. Meas. Tech., 9, 2927-2946, doi:10.5194/amt-9-2927-2016, 2016 Emissions from polar stratospheric cloud (PSC) particles affect the retrieved ozone and water vapor from the Limb Infrared Monitor of the Stratosphere (LIMS) satellite experiment. Threshold criteria are applied to the retrieved ozone for the detection and screening of those effects. The PSC effects correlate very well with regions of coldest temperatures (

Description: The 1816 ‘year without a summer’ in an atmospheric reanalysis Philip Brohan, Gilbert P. Compo, Stefan Brönnimann, Robert J. Allan, Renate Auchmann, Yuri Brugnara, Prashant D. Sardeshmukh, and Jeffrey S. Whitaker Clim. Past Discuss., doi:10.5194/cp-2016-78,2016 Manuscript under review for CP (discussion: open, 0 comments) We have used modern weather forecasting tools to reconstruct the dreadful European weather of 200 years ago – 1816 was the ‘year without a summer’; harvests failed, and people starved. We can show that 1816’s extreme climate was caused by the eruption of the Tambora volcano the previous year. This means we have some chance of predicting such extreme summers if they occur in future, though this is still a challenge to today’s forecast models.