An ice-ocean model study to explore climate change mechanisms in comparison with interannual-to-decadal variability of geochemical tracers

One way to identify the mechanisms that are crucial to Arctic climate change is to use existing data that exhibit interannual-to-decadal variability in the sea ice and ocean interior due to atmospheric forcing. Since around 1960s, valuable geochemical data of the ocean interior, together with atmospheric and sea ice data, have been analyzed and examined in a coupled ice–ocean model with an idealized configuration of the Arctic Basin. This is fundamentally driven by negative salt flux, in addition to atmospheric circulation and cooling. This strategy has a clear advantage over more sophisticated models with higher resolution that require extensive data collections for verification. Around 1990, the dominant atmospheric mode shifted from the Northern Annular Mode (NAM) to the Arctic Dipole Mode (ADM). The variability of sea ice cover was explained by these two modes sequentially and reproduced in the model. In particular, the geochemical fields indicated a movement of the Transpolar Drift Stream due to the NAM and an oscillation of the Pacific water between the Atlantic and Pacific sides due to the ADM. Both these features were reproduced reasonably well by the oceanic tracers in the model, including the time lags of about one third of the oscillation periods. Thus, this strategy can suggest methods and locations for monitoring oceanographic responses to Arctic climate change

Decadal Variability of Circulation in the Arctic Ocean Retrieved From Climatological Data by a Variational Method

[1] An inverse 3D finite-element ocean circulation model has been designed and used to study variability of the Arctic Ocean circulation in the last 4 decades. We obtained stationary model solutions with the temperature and salinity fields close to the ones given by the Environmental Working Group (EWG) [1998] atlas. Transports at the open boundaries, wind forcing and hydrographic fields are treated as unknowns, which are varied to minimize a quadratic cost function subject to model constraints. The inverse problem is solved for 10 gridded hydrographic data sets that were obtained as winter and summer averages of EWG data over each of the 4 decades (1950s to 1980s) and over the whole period of observations (1948-1993) documented in the atlas. The results show that Arctic circulation in the last 4 decades has undergone significant changes, which manifest themselves in (1) 10% reduction of the ventilation rate in the Atlantic sector of the Arctic Ocean; (2) substantial decrease of the advective heat and freshwater import at the lateral boundaries; (3) spinning down of the cyclonic gyre in the northern Greenland sea, which is partly driven by deep convection; and (4) 3400 km(3) increase of the net fresh water storage, with 75% taking place in the Atlantic sector of the Arctic Ocean. Most of these changes are similar to the ones observed on seasonal transition from winter to summer climatologies, and indicate that the Arctic Ocean is experiencing a shift toward a warmer state

Internal microstructure of arrested charnockite and surrounding gneiss from Kurunegala, Sri Lanka

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 国立極地研究所 ３階ラウン

Compositional change of hornblende and biotite during charnockite formation in Sri Lanka

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日（木） 国立極地研究所　2階大会議室前フロ

Antenatal antiarrhythmic treatment for fetal tachyarrhythmias: a study protocol for a prospective multicentre trial

Introduction Several retrospective or single-centrestudies demonstrated the efficacy of transplacentaltreatment of fetal tachyarrhythmias. Our retrospectivenationwide survey showed that the fetal therapy willbe successful at an overall rate of 90%. For fetuseswith hydrops, the treatment success rate will be 80%.However, standard protocol has not been established.The objective of this study is to evaluate the efficacy andsafety of the protocol-defined transplacental treatment offetal tachyarrhythmias. Participant recruitment began inOctober 2010.Methods and analysis The current study is a multicentre,single-arm interventional study. A total of 50 fetuseswill be enrolled from 15 Japanese institutions. Theprotocol-defined transplacental treatment is performed forsingletons with sustained fetal tachyarrhythmia ≥180 bpm,with a diagnosis of supraventricular tachycardia or atrialflutter. Digoxin, sotalol, flecainide or a combination is usedfor transplacental treatment. The primary endpoint isdisappearance of fetal tachyarrhythmias. The secondaryendpoints are fetal death related to tachyarrhythmia,proportion of preterm birth, rate of caesarean sectionattributable to fetal arrhythmia, improvement in fetalhydrops, neonatal arrhythmia, neonatal central nervoussystem disorders and neonatal survival. Maternal, fetal andneonatal adverse events are evaluated at 1 month afterbirth. Growth and development are also evaluated at 18and 36 months of corrected age.Ethics and dissemination The Institutional Review Boardof the National Cerebral and Cardiovascular Center ofJapan has approved this study. Our findings will be widelydisseminated through conference presentations and peerreviewedpublications

Effect of Pictorial Depth Cues, Binocular Disparity Cues and Motion Parallax Depth Cues on Lightness Perception in Three-Dimensional Virtual Scenes

Surface lightness perception is affected by scene interpretation. There is some experimental evidence that perceived lightness under bi-ocular viewing conditions is different from perceived lightness in actual scenes but there are also reports that viewing conditions have little or no effect on perceived color. We investigated how mixes of depth cues affect perception of lightness in three-dimensional rendered scenes containing strong gradients of illumination in depth.Observers viewed a virtual room (4 m width x 5 m height x 17.5 m depth) with checkerboard walls and floor. In four conditions, the room was presented with or without binocular disparity (BD) depth cues and with or without motion parallax (MP) depth cues. In all conditions, observers were asked to adjust the luminance of a comparison surface to match the lightness of test surfaces placed at seven different depths (8.5-17.5 m) in the scene. We estimated lightness versus depth profiles in all four depth cue conditions. Even when observers had only pictorial depth cues (no MP, no BD), they partially but significantly discounted the illumination gradient in judging lightness. Adding either MP or BD led to significantly greater discounting and both cues together produced the greatest discounting. The effects of MP and BD were approximately additive. BD had greater influence at near distances than far.These results suggest the surface lightness perception is modulated by three-dimensional perception/interpretation using pictorial, binocular-disparity, and motion-parallax cues additively. We propose a two-stage (2D and 3D) processing model for lightness perception

Introduction of the session on Global Change

Intenational Symposium "Toward a Sustainable Low Carbon Society -Green New Deal and Global Change-" PartII Global Change. 5 November 2009. Sapporo, Japan

Coupled climate-society modeling of a realistic scenario to achieve a sustainable Earth

A conceptual model was developed to project the global warming for this century. This model incorporated several important factors associated with the climate and society. Under the forcing of anthropogenic carbon dioxide, the climate system is represented by a global mean surface air temperature (SAT) and carbon storage, which is separated into the atmosphere, land and oceans. The SAT rises due to the atmospheric carbon, which is partially absorbed by the terrestrial ecosystem and the ocean. These absorption rates are reduced by the rising SAT. The anthropogenic carbon dioxide is emitted by society, which is described by global energy production (P) and energy efficiency/carbon intensity (E), yielding a rate of P/E. P consists of the energy production per capita (H) and the population (M) in developed countries and regions, P = H 9 M. These society components were set to grow, based on the historical record from the last 50 years, while societal incentives to reduce the growth rate H and to increase E in proportion to the increase in SAT were introduced. It is shown that, among the basic scenarios in the Special Report on Emissions Scenarios (SRES) for this century, medium-level carbon emission—where the growth rate of H is reduced by 30% and E is doubled, with 1 C of warming—could be achieved. Until the end of this century, both the terrestrial ecosystem and the oceans act as sinks. If societal incentives are eliminated, carbon emission approaches the upper limit considered in the SRES scenarios, and the terrestrial ecosystem changes into a source of carbon dioxide. Since H and E are closely related to lifestyle and technology, respectively, individuals in the developed countries are urged to change their lifestyles, and institutions need to develop low-carbon technologies and spread them to developing countries. When society achieves medium-level carbon emission for a couple of centuries, oceanic absorption was found to become more crucial than terrestrial absorption, so oceanic behavior has to be estimated more accurately