Future changes in the climate system could have significant impacts on the natural environment and human activities, which in turn affect changes in the climate system. In the interaction between ...natural and human systems under climate change conditions, land use is one of the elements that play an essential role. On the one hand, future climate change will affect the availability of water and food, which may impact land-use change. On the other hand, human-induced land-use change can affect the climate system through biogeophysical and biogeochemical effects. To investigate these interrelationships, we developed MIROC-INTEG-LAND (MIROC INTEGrated LAND surface model version 1), an integrated model that combines the land surface component of global climate model MIROC (Model for Interdisciplinary Research on Climate) with water resources, crop production, land ecosystem, and land-use models. The most significant feature of MIROC-INTEG-LAND is that the land surface model that describes the processes of the energy and water balance, human water management, and crop growth incorporates a land use decision-making model based on economic activities. In MIROC-INTEG-LAND, spatially detailed information regarding water resources and crop yields is reflected in the prediction of future land-use change, which cannot be considered in the conventional integrated assessment models. In this paper, we introduce the details and interconnections of the submodels of MIROC-INTEG-LAND, compare historical simulations with observations, and identify various interactions between the submodels. By evaluating the historical simulation, we have confirmed that the model reproduces the observed states well. The future simulations indicate that changes in climate have significant impacts on crop yields, land use, and irrigation water demand. The newly developed MIROC-INTEG-LAND could be combined with atmospheric and ocean models to develop an integrated earth system model to simulate the interactions among coupled natural–human earth system components.
A yellow sand transport episode from the Asian continent to Japan and North America which occurred in April 1998 is simulated. A new on‐line dust tracer model coupled with a regional‐scale ...meteorological model is developed and applied to this dust storm episode. The results for two large dust events that started during April 14–15 and 19–20, 1998, have been analyzed and discussed. The first dust storm was trapped in a cutoff vortex developed over the China plain. A modeled 3‐D structure of dust associated with this cutoff vortex agreed with an observed time‐height cross section of dust concentration. Results show that the strong subsidence at the backside of the vortex restricted the dust layer below 3 km level. Model analysis revealed that the second dust event that started during April 19–20 over inland China was the origin of a dust episode reported over North America. The trans‐Pacific dust transport simulation successfully showed the dust onset near the West Coast of North America. Elevation of the dust layer during the long‐range transport was below 3 km. The model is extended to include the transport of an Asian origin anthropogenic tracer over the North Pacific Rim. Both the natural‐origin mineral dust and the Asian‐origin anthropogenic tracer are simultaneously transported even if their emission regions are different.
Using a high‐resolution atmosphere–ocean coupled climate model, responses of the Kuroshio and the Kuroshio Extension (KE) to global warming are investigated. In a climate change experiment with ...atmospheric CO2 concentration ideally increased by 1% year−1, the current velocity of the Kuroshio and KE increases, while the latitude of the Kuroshio separation to the east of Japan does not change significantly. The increase of the current velocity is up to 0.3 m s−1 at 150°E. This acceleration of the Kuroshio and KE is due to changes in wind stress over the North Pacific and consequent spin‐up of the Kuroshio recirculation gyre. The acceleration of the currents may affect sea level along the southern coast of Japan and northward heat transport under global warming.
Ground-state magnetic moments of 30Al and 32Al were measured with the β-NMR method using radioactive-isotope beams spin-polarized in the projectile-fragmentation reaction. Polarization of sizes ...|P|=0.5–1% were obtained in spite of the large numbers of nucleons that are removed from the projectile 40Ar, providing a promising prospect that substantial polarizations are obtained even in fragment nuclei that are far removed from the projectile nucleus. The obtained μ moments, |μexp(Al30)|=3.010(7) μN and |μexp(Al32)|=1.959(9) μN, are in agreement with shell model calculations within the sd valence space, although a reduction in the energy-gap between the sd and pf states is predicted for 32Al in recent theoretical studies.
The first measurement of a magnetic moment of
19N was performed by combining a β-NMR method with a spin-polarized radioactive nuclear beam from the fragmentation reaction. As a result, the
g value ...for the
19N ground state,
g = 0.61 ± 0.03 (preliminary), was obtained. The value was compared with those of
15N and
17N. Contrary to shell-mode predictions that the
g value should increase with increasing number of neutrons in the
sd shell, the obtained
g for
19N
g.s. is significantly smaller than
g(
17N
g.s.) previously obtained.
In order to investigate the interaction between cumulus convection and soil moisture distribution, two‐dimensional numerical experiments using a regional atmospheric model are performed. The model ...roughly resolves each convective cell and represents cloud processes by a microphysics parameterization. Two long‐term (60‐day) integrations with relatively dry and wet conditions are made with the atmosphere‐land system in a quasi‐equilibrium state. Though the initial and boundary conditions are horizontally homogeneous, horizontal contrasts in soil moisture spontaneously develop due to the spotty nature of convective precipitation. When intense soil moisture contrasts develop, they cause surface temperature contrasts through a change in evaporation. As a result, thermally induced local circulations occur in the daytime, with upward branches over the dry and hot regions and downward branches over the wet and cool regions. Most cumulus convection events are initiated by the upward motion of this local circulation over the dry region. They mostly occur in the afternoon (1300–1700 LT), while convection that forms over regions that are wet throughout may occur at any time during the day. The intense precipitation over the dry region “overdamps” the soil moisture contrast, which results in the maintenance of a heterogeneous distribution of soil moisture.
Results from time‐slice ensemble experiments using a T106 AGCM revealed changes in the South Asian summer monsoon resulting from climate change. Model results under global warming conditions ...suggested more warming over land than over the ocean, a northward shift of lower tropospheric monsoon circulation, and an increase in mean precipitation during the Asian summer monsoon. The number of extreme daily precipitation events increased significantly. Increases in mean and extreme precipitation were attributed to greater atmospheric moisture content (a thermodynamic change). In contrast, dynamic changes limited the intensification of mean precipitation. Enhanced extreme precipitation over land in South Asia arose from dynamic changes rather than thermodynamic changes.
Results from time-slice ensemble experiments using a T106 AGCM revealed changes in the South Asian summer monsoon resulting from climate change. Model results under global warming conditions ...suggested more warming over land than over the ocean, a northward shift of lower tropospheric monsoon circulation, and an increase in mean precipitation during the Asian summer monsoon. The number of extreme daily precipitation events increased significantly. Increases in mean and extreme precipitation were attributed to greater atmospheric moisture content (a thermodynamic change). In contrast, dynamic changes limited the intensification of mean precipitation. Enhanced extreme precipitation over land in South Asia arose from dynamic changes rather than thermodynamic changes.
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 MIROC 3.2) 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 degree C is hard to reconcile with the paleoclimate record, and that of greater than 8 degree C seems virtually impossible. Our estimate for the most likely climate sensitivity is in the region of 4.5 degree 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.
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