A relatively high‐resolution (T106) atmospheric general circulation model (AGCM) was used to simulate the present‐day climate with two different assumptions in cumulus parameterization. While the two ...runs show comparable performance for the annual mean precipitation, one shows much better agreement with satellite‐based analysis data for the extreme daily precipitation than the other. Accumulation of convectively available potential energy is shown to be important for more realistic intensities of extreme precipitation. This demonstrates that the performance of an AGCM for extreme precipitation is strongly dependent on cumulus parameterization even when the resolution of the model is as high as 1°, but can be reasonably good with an adequate choice of cumulus parameterization. A time‐slice doubled CO2 experiment was also conducted with the better version of the model. Though the global mean percentage change is larger for extreme precipitation than for the annual mean, this relation is found to vary regionally.
It is now widely recognized that climate change affects multiple sectors in virtually every part of the world. Impacts on one sector may influence other sectors, including seemingly remote ones, ...which we call “interconnections of climate risks.” While a substantial number of climate risks are identified in the Intergovernmental Panel on Climate Change Fifth Assessment Report, there have been few attempts to explore the interconnections between them in a comprehensive way. To fill this gap, we developed a methodology for visualizing climate risks and their interconnections based on a literature survey. Our visualizations highlight the need to address climate risk interconnections in impact and vulnerability studies. Our risk maps and flowcharts show how changes in climate impact natural and socioeconomic systems, ultimately affecting human security, health, and well‐being. We tested our visualization approach with potential users and identified likely benefits and issues. Our methodology can be used as a communication tool to inform decision makers, stakeholders, and the general public of the cascading risks that can be triggered by climate change.
Plain Language Summary
The paper demonstrates in a most holistic manner how climate change can generate various risks and how they are actually interconnected. Based on a literature survey using the Intergovernmental Panel on Climate Change Fifth Assessment Report, we identified 91 climate risks and 253 causal relationships among them and graphically drew such interconnected risks. We found that changes in the climate system impact the natural and socioeconomic system, influencing ultimately human security, health, and well‐being. This indicates that climate change can trigger a cascade of impacts across sectors. Our findings point to the need to address the climate risk interconnections in impact and vulnerability studies. We tested our visualization approach with potential users and identified likely benefits and issues. The implications of our study go beyond science. Our study is useful to inform stakeholders of a broad yet fresh perspective of climate risks that have not been presented before.
Key Points
The paper developed a methodology for visualizing how climate change can generate various risks and how they can be interconnected
We identified 91 climate risks and 253 causal relationships among them based on a literature survey and graphically presented the interconnected risks
We found that changes in the climate system impact natural and socioeconomic systems, ultimately influencing human security, health, and well‐being
In the present study we investigate the performance of climate models which contributed to the past 3 Intergovernmental Panel for Climate Change (IPCC) assessment reports for the Gangetic West Bengal ...region of east India (6° × 6°). Analysing present-day seasonal rainfall and temperature over the domain, we compare the results of the models (from the 6 modelling centres common to the second, third and fourth assessment reports—SAR, TAR and AR4, respectively) in order to judge to what extent these global models have improved on a regional scale. Metrics for model evaluation are not yet firmly established in the literature, so in this paper we compare and contrast the results from a number of different statistics used in previous studies. We also analyse the impact of topography on the results obtained for the AR4 models. We find that most models improved from SAR to AR4, although there is some variation in this result depending on seasons, variables and on which statistical methods are used in the analysis. The multi-model mean of the 6 models improves from SAR to TAR to AR4. The overall best performance in this region in the AR4 is the Japanese model, MIROC, but the best model in terms of improving skill from SAR to AR4 is the GFDL model from the United States. Correcting for errors in the model topographies produced an overall improvement of spatial patterns and error statistics, and greatly improves the performance of 1 model (CGCM) which has poor topography, but does not affect the ranking of the other models.
Two versions of a coupled atmosphere‐ocean general circulation model (GCM) with different climate sensitivities are tested on global cooling following the Pinatubo volcanic eruption to investigate ...the validity of high climate sensitivities. The higher‐sensitivity version, with climate sensitivity of 6.3 K for doubled CO2 forcing, overestimates cooling due to the volcanic eruption, whereas the lower‐sensitivity version (4.0 K) produces results consistent with observations. A simple scheme for climate feedback analysis is devised and it is found that the difference between the two versions is attributed to cloud‐albedo feedback. This validation method is expected to provide additional constraints on climate sensitivity and possibly lead to reduced uncertainties in climate prediction.
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.
Spin-orbit torque (SOT) is an emerging technology that enables the efficient manipulation of spintronic devices. The initial processes of interest in SOTs involved electric fields, spin-orbit ...coupling, conduction electron spins, and magnetization. More recently, interest has grown to include a variety of other processes that include phonons, magnons, or heat. Over the past decade, many materials have been explored to achieve a larger SOT efficiency. Recently, holistic design to maximize the performance of SOT devices has extended material research from a nonmagnetic layer to a magnetic layer. The rapid development of SOT has spurred a variety of SOT-based applications. In this article, we first review the theories of SOTs by introducing the various mechanisms thought to generate or control SOTs, such as the spin Hall effect, the Rashba-Edelstein effect, the orbital Hall effect, thermal gradients, magnons, and strain effects. Then, we discuss the materials that enable these effects, including metals, metallic alloys, topological insulators, 2-D materials, and complex oxides. We also discuss the important roles in SOT devices of different types of magnetic layers, such as magnetic insulators, antiferromagnets, and ferrimagnets. Afterward, we discuss device applications utilizing SOTs. We discuss and compare three- and two-terminal SOT-magnetoresistive random access memories (MRAMs); we mention various schemes to eliminate the need for an external field. We provide technological application considerations for SOT-MRAM and give perspectives on SOT-based neuromorphic devices and circuits. In addition to SOT-MRAM, we present SOT-based spintronic terahertz generators, nano-oscillators, and domain-wall and skyrmion racetrack memories. This article aims to achieve a comprehensive review of SOT theory, materials, and applications, guiding future SOT development in both the academic and industrial sectors.
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.
We use a recently-developed efficient probabilistic estimation technique to estimate the sensitivity of the Earth’s temperature to a doubling of atmospheric carbon dioxide. The method is based on the ...ensemble Kalman filter which we apply to the CCSR/NIES/FRCGC AGCM (the atmospheric component of MIROC3.2) at T21L20 resolution coupled to a slab ocean. The method combines prior beliefs about the model, with observational data, to simultaneously estimate 25 model parameters in an efficient and objective manner. We perform a sensitivity analysis to investigate the effect of different assumptions regarding model error, since this is a necessarily subjective input which has not yet been well characterised. We attempt to validate the resulting ensembles against out-of-sample data by comparing their hindcasts of the Last Glacial Maximum (LGM) to paleoclimate proxy data, and demonstrate through this that our ensembles of simulations are probably biased towards too high a sensitivity. Within the framework of our single-model ensemble experiment, we show that climate sensitivity of much greater than 6°C is hard to reconcile with the paleoclimate record, and that of greater than 8°C seems virtually impossible. Our estimate for the most likely climate sensitivity is in the region of 4.5°C. Although these results are reasonably consistent with the most widely accepted estimates of climate sensitivity, they disagree with some recent research which has suggested a significant probability of sensitivities well in excess of these values. These results suggest that paleoclimatic evidence could provide a useful, albeit imprecise, constraint on ensemble forecasts of future climate change.
In climate change projections, inter-model differences in cloud feedback have been identified as the largest source of uncertainty. The source terms of the cloud condensate tendency equation (CCTD) ...are expected to be useful diagnostics to better understand the different cloud responses to a CO2 increase in GCMs. To demonstrate the idea, analysis of the CCTD response to CO2 doubling is presented using two versions of a climate model with different climate sensitivities of 6.2°C ('HS'version) and 4.1°C ('LS'version). The model's response to CO2 doubling is characterized with a marked difference in the cloud feedback between the two versions, which is consistent with the cloud response in the southern middle latitudes: cloud decreases in the HS version and increases in the LS version. Analysis of the source terms reveals that the difference in cloud response is attributable to the ice sedimentation process. The results also suggest the importance of the vertical cloud ice profile which controls the ice sedimentation response to a CO2 increase, indicating the potential for providing constraints on the aspect of cloud feedback.
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