We describe the behaviour of 23 dynamical ocean-atmosphere models, in the context of comparison with observations in a common framework. Fields of tropical sea surface temperature (SST), surface wind ...stress and upper ocean vertically averaged temperature (VAT) are assessed with regard to annual mean, seasonal cycle, and interannual variability characteristics. Of the participating models, 21 are coupled GCMs, of which 13 use no form of flux adjustment in the tropics. The models vary widely in design, components and purpose: nevertheless several common features are apparent. In most models without flux adjustment, the annual mean equatorial SST in the central Pacific is too cool and the Atlantic zonal SST gradient has the wrong sign. Annual mean wind stress is often too weak in the central Pacific and in the Atlantic, but too strong in the west Pacific. Few models have an upper ocean VAT seasonal cycle like that observed in the equatorial Pacific. Interannual variability is commonly too weak in the models: in particular, wind stress variability is low in the equatorial Pacific. Most models have difficulty in reproducing the observed Pacific 'horseshoe' pattern of negative SST correlations with interannual Nino3 SST anomalies, or the observed Indian-Pacific lag correlations. The results for the fields examined indicate that several substantial model improvements are needed, particularly with regard to surface wind stress.
For rubber-modified epoxy adhesives with high rubber content, stable crack propagation is observed under mode I loading. In such a situation, a further increase in rubber content not only extends the ...plastic zone in front of the crack tip, but also promotes the formation and growth of voids in the adhesive layer. To clarify the effect of a further increase in rubber content on crack initiation and propagation behavior, fracture toughness tests were conducted under mode I loading using adhesively bonded double cantilever beam (DCB) and compact tension (CT) specimens: these specimens were used for evaluating the crack growth resistance and fracture toughness in the initial stage of crack propagation, respectively. Stable behavior in crack growth was observed for adhesives with rubber contents of both 10 and 14
wt%. The crack growth resistance of the adhesive with 14
wt% rubber was higher than that with 10
wt%, whereas in the initial stage of crack propagation the energy release rate for 10
wt% rubber was higher than that for 14
wt%. The crack growth behavior of the DCB specimen was discussed on the basis of Gurson’s model. The estimated R-curve agreed well with the experimental result in the initial stage of crack propagation, although the difference between estimated and experimental plots increased with crack growth.
An ensemble of twenty four coupled ocean-atmosphere models has been compared with respect to their performance in the tropical Pacific. The coupled models span a large portion of the parameter space ...and differ in many respects. The intercomparison includes TOGA (Tropical Ocean Global Atmosphere)-type models consisting of high-resolution tropical ocean models and coarse-resolution global atmosphere models, coarse-resolution global coupled models, and a few global coupled models with high resolution in the equatorial region in their ocean components. The performance of the annual mean state, the seasonal cycle and the interannual variability are investigated. The primary quantity analysed is sea surface temperature (SST). Additionally, the evolution of interannual heat content variations in the tropical Pacific and the relationship between the interannual SST variations in the equatorial Pacific to fluctuations in the strength of the Indian summer monsoon are investigated. The results can be summarised as follows: almost all models (even those employing flux corrections) still have problems in simulating the SST climatology, although some improvements are found relative to earlier intercomparison studies. Only a few of the coupled models simulate the El Nino/Southern Oscillation (ENSO) in terms of gross equatorial SST anomalies realistically. In particular, many models overestimate the variability in the western equatorial Pacific and underestimate the SST variability in the east. The evolution of interannual heat content variations is similar to that observed in almost all models. Finally, the majority of the models show a strong connection between ENSO and the strength of the Indian summer monsoon.
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Dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes the endogenous nitric oxide synthase inhibitors NG‐monomethyl‐L‐arginine and NG, NG‐dimethy‐L‐arginine to citrulline, was ...identified by Western blotting in rat and human tissue homogenates.
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S‐2‐amino‐4(3‐methylguanidino)butanoic acid (4124W) inhibited the metabolism of 14C‐NG‐monomethyl‐L‐arginine to 14C‐citrulline by rat liver homogenates (IC50 416 ± 66μm; n = 9), human cultured endothelial cells (IC50 250 ± 34 μm; n = 9)and isolated purified dimethylarginine dimethylaminohydrolase.
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Addition of 4124W to culture medium increased the accumulation of endogenously‐generated NG, NG‐dimethy‐L‐arginine in the supernatant of human cultured endothelial cells from 3.1 ± 0.3 to 5 ± 0.7 μm (n=15; P < 0.005).
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4124W (1 μm‐1 mM) had no direct effect on endothelial nitric oxide synthase activity but caused endothelium‐dependent contraction of rat aortic rings (1 mM 4124W increased tone by 81.5 ± 9.6% of that caused by phenylephrine 100 nM). This effect was reversed by L‐arginine (100 μm). 4124W reversed endothelium‐dependent relaxation of human saphenous vein (19.2 ± 6.7% reversal of bradykinin‐induced relaxation at 1 mM 4124W).
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These data suggest that inhibition of dimethylarginine dimethylaminohydrolase increases the intracellular concentration of NG, NG‐dimethyl‐L‐arginine sufficiently to inhibit nitric oxide synthesis. Inhibiting the activity of DDAH may provide an alternative mechanism for inhibition of nitric oxide synthases and changes in the activity of DDAH could contribute to pathophysiological alterations in NO generation.
The Decadal Climate Prediction Project (DCPP) is a coordinated multi-model investigation into decadal climate prediction, predictability, and variability. The DCPP makes use of past experience in ...simulating and predicting decadal variability and forced climate change gained from the fifth Coupled Model Intercomparison Project (CMIP5) and elsewhere. It builds on recent improvements in models, in the reanalysis of climate data, in methods of initialization and ensemble generation, and in data treatment and analysis to propose an extended comprehensive decadal prediction investigation as a contribution to CMIP6 (Eyring et al., 2016) and to the WCRP Grand Challenge on Near Term Climate Prediction (Kushnir et al., 2016). The DCPP consists of three components. Component A comprises the production and analysis of an extensive archive of retrospective forecasts to be used to assess and understand historical decadal prediction skill, as a basis for improvements in all aspects of end-to-end decadal prediction, and as a basis for forecasting on annual to decadal timescales. Component B undertakes ongoing production, analysis and dissemination of experimental quasi-real-time multi-model forecasts as a basis for potential operational forecast production. Component C involves the organization and coordination of case studies of particular climate shifts and variations, both natural and naturally forced (e.g. the “hiatus”, volcanoes), including the study of the mechanisms that determine these behaviours. Groups are invited to participate in as many or as few of the components of the DCPP, each of which are separately prioritized, as are of interest to them.The Decadal Climate Prediction Project addresses a range of scientific issues involving the ability of the climate system to be predicted on annual to decadal timescales, the skill that is currently and potentially available, the mechanisms involved in long timescale variability, and the production of forecasts of benefit to both science and society.
A coupled ocean-atmosphere climate model is used to depict changes in precipitation characteristics around Japan in the 21st century. A comparison between high (T106 atmosphere) and medium (T42) ...resolution versions for the present-day climate shows that the higher resolution version better represents not only the mean but also the frequency distribution of precipitation. The climate projection for the 21st century by the high resolution version shows that mean precipitation increases more than 10% in 100 years from the present, especially in warm seasons. Increases in frequencies of non-precipitating and heavy (≥30 mm day-1) rainfall days and decrease in relatively weak (1-20 mm day-1) rainfall days are significant.
There is growing interest in the field of decadal climate prediction, supported by observational evidence of natural decadal climate variations with significant regional impacts, and evidence of ...potential skill from idealized predictability studies and pioneering attempts at predictions obtained by initializing climate models with observations. A synthesis of the current state of observed decadal climate variability (DCV) characteristics and some examples of DCV impacts on climate on land is given. Aspects of DCV arising either from internal climate variability or from natural external forcing were described. The potential predictability from these sources, and also from the influence of anthropogenic external forcing is considered. As this new area of climate science is at an early stage, a number of significant challenges need to be addressed if practical prediction systems capable of producing credible projections at regional scales for use by scientists, stakeholders and planners are to be provided and summary of these challenges is given.
The broad climatological features associated with the Asian monsoon circulation, including its mean state and intraseasonal and interannual variability over the Indian subcontinent, as simulated in ...the CCSR/NIES coupled A–O GCM in its control experiment are presented in this paper. The model reproduces the seasonal cycle as well as basic observed patterns of key climatic parameters, in spite of some limitations in simulation of the monsoon rainfall. While the seasonality in rainfall over the region is well simulated and the simulated area-averaged monsoon rainfall is only marginally higher than the observed rainfall, the peak rainfall is simulated to be about two-thirds of the observed precipitation intensity over central India. The transient experiments performed with the model following the four SRES 'Marker' emission scenarios, which include revised trends for all the principal anthropogenic forcing agents for the future, suggest an annual mean area-averaged surface warming over the Indian subcontinent to range between 3.5 and 5.5°C over the region during 2080s. During winter, India may experience between 5 and 25% decline in rainfall. The decline in wintertime-rainfall over India is likely to be significant and may lead to droughts during the dry summer months. Only a 10 to 15% increase is projected in area-averaged summer monsoon rainfall over the Indian subcontinent. The date of onset of summer monsoon over India could become more variable in future.
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