http://www.sciencedirect.com/science/article/pii/S167498711400108X

We present three 3D numerical models of deep subduction where buoyant material from an oceanic plateau and a plume interact with the overriding plate to assess the influence on subduction dynamics,trench geometry,and mechanisms for plateau accretion and continental growth.Transient instabilities of the convergent margin are produced,resulting in:contorted trench geometry;trench migration parallel with the plate margin;folding of the subducting slab and orocline development at the convergent margin;and transfer of the plateau to the overriding plate.The presence of plume material beneath the oceanic plateau causes flat subduction above the plume,resulting in a "bowed" shaped subducting slab.In plateau-only models,plateau accretion at the edge of the overriding plate results in trench migration around the edge of the plateau before subduction is re-established directly behind the trailing edge of the plateau.The plateau shortens and some plateau material subducts.The presence of buoyant plume material beneath the oceanic plateau has a profound influence on the behaviour of the convergent margin.In the plateau + plume model,plateau accretion causes rapid trench advance.Plate convergence is accommodated by shearing at the base of the plateau and shortening in the overriding plate.The trench migrates around the edge of the plateau and subduction is re-established well behind the trailing edge of the plateau,effectively embedding the plateau into the overriding plate.A slab window forms beneath the accreted plateau and plume material is transferred from the subducting plate to the overriding plate through the window.In all of the models,the subduction zone maintains a relatively stable configuration away from the buoyancy anomalies within the downgoing plate.The models provide a dynamic context for plateau and plume accretion in Phanerozoic accretionary orogenic systems such as the East China Orogen and the Central Asian Orogen(Altiads),which are characterised by accreted ophiolite complexes with diverse geochemical affinities,and a protracted evolution of accretion of exotic terranes including oceanic plateau and terranes with plume origins.     

Colloidal Stability and Toxicity of Gold Nanoparticles and Gold Chloride on <Emphasis Type="Italic">Chlamydomonas reinhardtii</Emphasis>

Here we have examined interactions of gold nanoparticles differing in primary particle size and coating with the green algae Chlamydomonas reinhardtii as function of the colloidal stability of the particles in the experimental media used for toxicity studies. Interactions of dissolved Au³⁺ ions with algae were also examined. Included endpoints were photosynthetic yield and algal growth. Morphological and structural effects were examined microscopically and by flow cytometry. The results indicate no significant toxicity of gold nanoparticles to C. reinhardtii. Analysis of published data suggests toxicity of gold nanoparticles on algal growth to relate rather to particular coatings than to the gold core.     

Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed,Reanalysis and Regional Climate Model Data

This study investigates the recent near-surface temperature trends over the Antarctic Peninsula.We make use of available surface observations,ECMWF’s ERA5 and its predecessor ERA-Interim,as well as numerical simulations,allowing us to contrast different data sources.We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km(PWRF-45)and 15 km(PWRF-15)spatial resolutions for the period 1991?2015.In addition,we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain(~50 km)for further comparisons.Results show that there is a marked windward warming trend except during summer.This windward warming trend is particularly notable in the autumn season and likely to be associated with the recent deepening of the Amundsen/Bellingshausen Sea low and warm advection towards the Antarctic Peninsula.On the other hand,an overall summer cooling is characterized by the strengthening of the Weddell Sea low as well as an anticyclonic trend over the Amundsen Sea accompanied by northward winds.The persistent cooling trend observed at the Larsen Ice Shelf station is not captured by ERA-Interim,whereas hindcast simulations indicate that there is a clear pattern of windward warming and leeward cooling.Furthermore,larger temporal correlations and lower differences exhibited by PWRF-15 illustrate the existence of the added value in the higher spatial resolution simulation.     

A Validation of CloudSat and CALIPSO's Temperature,Humidity, Cloud Detection,and Cloud Base Height over the Arctic Marine Cryosphere

Abstract

This study presents a semi‐analytic non‐iterative solution for the Monin‐Obukhov similarity equations under unstable surface conditions. The solution is represented in terms of the non‐dimensional Monin‐Obukhov stability parameter z/L. This parameter is given as a function of the bulk Richardson number and other surface parameters including the heat and momentum roughness lengths which are generally assumed to be different in this formulation. The proposed formulations give results that are both quantitatively and qualitatively consistent with the fully iterated numerical solution for a wide range of surface parameters.