The monitoring and prediction of climate-induced variations in crop yields, production and export prices in major food-producing regions have become important to enable national governments in import-dependent countries to ensure supplies of affordable food for consumers. Although the El Niño/Southern Oscillation (ENSO) often affects seasonal temperature and precipitation, and thus crop yields in many regions, the overall impacts of ENSO on global yields are uncertain. Here we present a global map of the impacts of ENSO on the yields of major crops and quantify its impacts on their global-mean yield anomalies. Results show that El Niño likely improves the global-mean soybean yield by 2.1-5.4% but appears to change the yields of maize, rice and wheat by À 4.3 to þ 0.8%. The global-mean yields of all four crops during La Niña years tend to be below normal ( À 4.5 to 0.0%). Our findings highlight the importance of ENSO to global crop production.

Summary An eddy-resolving hindcast experiment forced by daily mean atmospheric reanalysis data covering the second half of the twentieth century was completed successfully on the Earth Simulator. The domain covers quasiglobal from 75 • S to 75 • N excluding arctic regions, with horizontal resolution of 0.1 • and 54 • vertical levels. Encouraged by high performance of the preceding spin-up integration in capturing the time-mean and transient eddy fields of the world oceans, the hindcast run is executed to see how well the observed variations in the low-and midlatitude regions spanning from intraseasonal to decadal timescales are reproduced in the simulation. Our report presented here covers, among others, the El Niño and the Indian Ocean Dipole events, the Pacific and the Pan-Atlantic decadal oscillations, and the intraseasonal variations in the equatorial Pacific and Indian Oceans, which are represented well in the hindcast simulation, comparing with the observations. The simulated variations in not only the surface but also subsurface layers are compared with observations, for example, the decadal subsurface temperature change with narrow structures in the Kuroshio Extension region. Furthermore, we focus on the improved aspects of the hindcast simulation over the spin-up run, possibly brought about by realistic high-frequency daily mean forcing.

An atmosphere-ocean coupled general circulation model known as the Scale Interaction Experiment Frontier version 1 (SINTEX-F1) model is used to understand the intrinsic variability of the Indian Ocean dipole (IOD). In addition to a globally coupled control experiment, a Pacific decoupled noENSO experiment has been conducted. In the latter, the El Niño-Southern Oscillation (ENSO) variability is suppressed by decoupling the tropical Pacific Ocean from the atmosphere. The ocean-atmosphere conditions related to the IOD are realistically simulated by both experiments including the characteristic east-west dipole in SST anomalies. This demonstrates that the dipole mode in the Indian Ocean is mainly determined by intrinsic processes within the basin. In the EOF analysis of SST anomalies from the noENSO experiment, the IOD takes the dominant seat instead of the basinwide monopole mode. Even the coupled feedback among anomalies of upper-ocean heat content, SST, wind, and Walker circulation over the Indian Ocean is reproduced.As in the observation, IOD peaks in boreal fall for both model experiments. In the absence of ENSO variability the interannual IOD variability is dominantly biennial. The ENSO variability is found to affect the periodicity, strength, and formation processes of the IOD in years of co-occurrences. The amplitudes of SST anomalies in the western pole of co-occurring IODs are aided by dynamical and thermodynamical modifications related to the ENSO-induced wind variability. Anomalous latent heat flux and vertical heat convergence associated with the modified Walker circulation contribute to the alteration of western anomalies. It is found that 42% of IOD events affected by changes in the Walker circulation are related to the tropical Pacific variabilities including ENSO. The formation is delayed until boreal summer for those IODs, which otherwise form in boreal spring as in the noENSO experiment.

During 2006 and 2007 boreal fall, two consecutive positive Indian Ocean Dipole (pIOD) events occurred unprecedentedly regardless of the respective El Niño and La Niña condition in the Pacific. These two pIOD events had large climate impacts, particularly in the Eastern Hemisphere. Experimental forecasts using a coupled model show that the two pIOD events can be predicted 3 or 4 seasons ahead. The evolution of the 2006 pIOD is consistent with the large‐scale IOD dynamics, and therefore, it has long‐lead predictability owing to the oceanic subsurface memory in the South Indian Ocean. The 2007 pIOD event, however, is rather weak and peculiar without a long memory from the off‐equatorial ocean. The model has less predictability for this weak event. The results show that seasonal climate anomalies in the Eastern Hemisphere associated with the two pIOD events can be predicted 1–2 seasons ahead. This indicates potential societal benefits of IOD prediction.

Dissipative properties of various kinds of turbulent phenomena are investigated. Two expressions are derived for the rate of entropy increase due to thermal and viscous dissipation by turbulence, and for the rate of entropy increase in the surrounding system; both rates must be equal when the fluid system is in a steady state. Possibility is shown with these expressions that the steady-state properties of several different types of turbulent phenomena (Bénard-type thermal convection, turbulent shear flow, and the general circulation of the atmosphere and ocean) exhibit a unique state in which the rate of entropy increase in the surrounding system by the turbulent dissipation is at a maximum. The result suggests that the turbulent fluid system tends to be in a steady state with a distribution of eddies that produce the maximum rate of entropy increase in the nonequilibrium surroundings.

USAConsumers, including the poor in many countries, are increasingly dependent on food imports 1 and are therefore exposed to variations in yields, production, and export prices in the major food-producing regions of the world. National governments and commercial entities are therefore paying increased attention to the cropping forecasts of major food-exporting countries as well as to their own domestic food production. Given the increased volatility of food markets and the rising incidence of climatic extremes affecting food production, food price spikes may increase in prevalence in future years 2-4 . Here we present a global assessment of the reliability of crop failure hindcasts for major crops at two lead times derived by linking ensemble seasonal climatic forecasts with statistical crop models. We found that moderate-to-marked yield loss over a substantial percentage (26-33%) of the harvested area of these crops is reliably predictable if climatic forecasts are near perfect. However, only rice and wheat production are reliably predictable at three months before the harvest using within-season hindcasts. The reliabilities of estimates varied substantially by crop-rice and wheat yields were the most predictable, followed by soybean and maize. The reasons for variation in the reliability of the estimates included the differences in crop sensitivity to the climate and the technology used by the crop-producing regions. Our findings reveal that the use of seasonal climatic forecasts to predict crop failures will be useful for monitoring global food production and will encourage the adaptation of food systems to climatic extremes.Although global crop monitoring and yield prediction models (e.g., the Global Information and Early Warning System of the FAO 5 and the Famine Early Warning Systems Network 6 ) have been developed, few studies have evaluated the reliability of seasonal climatic forecast-based cropping predictions on a global scale to date. However, global commodity markets are essential to maintaining national food balances and affordable access for consumers, including the poor 7, 8 . Large increases in food prices since 2008, occurring as a result of the widespread drought in crop-export regions in 2008 and 2012, coupled with a transforming food system (i.e., the increasing production of biofuels) increase the importance of being able to anticipate large changes in food production 9-11 . These changes affect both the rural and urban poor who are reliant on imports from the global commodity market to ensure that a sufficient amount of food is available to meet demand.We conducted a global overview of the reliability of crop failure forecasts for maize, rice, wheat, and soybean, which are the principal cereal and legume crops worldwide, providing nearly 60% of all calories produced on croplands 12 . The key question posed was "How reliable is the forecasting of crop failure at lead times that allow such information to be of value to governments and commercial concerns?" Previous work on this topic focus...

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The recent formation of the Kuroshio large meander southeast of the Kii Peninsula during the period from May to July 2004 has been simulated successfully in an eddy‐resolving ocean forecast system (Japanese Coastal Ocean Predictability Experiment). The formation process was examined from the viewpoint of eddy‐Kuroshio interactions using sensitivity experiments that had various initial conditions for eddies in March and May 2004. We confirmed that the large meander does not occur when the trigger meander southeast of the Kyushu Island has small amplitude and that the cyclonic eddy on the offshore side of the Kuroshio contributes to the large meander formation. Our results show that the large amplitude of the trigger meander southeast of Kyushu Island in April 2004 was caused by downstream advection of anticyclonic eddies along the Kuroshio in the East China Sea from east of Taiwan. The results suggest that the successive westward propagation of strong anticyclonic eddies in the subtropical frontal region from 2003 to 2004 was the origin of the formation of the Kuroshio large meander south of Japan in summer 2004.