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S. Manabe R. T. Wetherald P. C. D. Milly T. L. Delworth R. J. Stouffer 《Climatic change》2004,64(1-2):59-76
It has been suggested that, unless a major effort is made, the atmospheric concentration of carbon dioxide may rise above four times the pre-industrial level in a few centuries. Here we use a coupled atmosphere-ocean-land model to explore the response of the global water cycle to such a large increase in carbon dioxide, focusing on river discharge and soil moisture. Our results suggest that water is going to be more plentiful in those regions of the world that are already `water-rich'. However, water stresses will increase significantly in regions and seasons that are already relatively dry. This could pose a very challenging problem for water-resource management around the world. For soil moisture, our results indicate reductions during much of the year in many semi-arid regions of the world, such as the southwestern region of North America, the northeastern region of China, the Mediterranean coast of Europe, and the grasslands of Australia and Africa. In some of these regions, soil moisture values are reduced by almost a factor of two during the dry season. The drying in semi-arid regions is likely to induce the outward expansion of deserts to the surrounding regions. Over extensive regions of both the Eurasian and North American continents in high and middle latitudes, soil moisture decreases in summer but increases in winter, in contrast to the situation in semi-arid regions. For river discharge, our results indicate an average increase of ～ 15% during the next few centuries. The discharges from Arctic rivers such as the Mackenzie and Ob' increase by much larger fractions. In the tropics, the discharges from the Amazonas and Ganga-Brahmaputra also increase considerably. However, the percentage changes in runoff from other tropical and many mid-latitude rivers are smaller. 相似文献
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Ken-Ichi Manabe 《Quaternary Research》1977,7(3):372-379
Paleomagnetic measurements have been carried out on 103 specimens taken at about 15 cm intervals in a sea cliff exposing the marine terrace formation. Secondary components were removed by partial demagnetization in a peak field of 200 Oe. Two short reversed magnetozones are recognized. Geological and biostratigraphical evidence indicates that they are equivalent to the Blake event, which was first reported by Smith and Foster (1969) (Science 163, 565–567) from the North Atlantic deep-sea cores. The present result suggests a split nature for the Blake Event. 相似文献
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The temporal variability of soil wetness and its interactions with the atmosphere were studied using a general circulation model of the atmosphere. It was found that time series of soil wetness computed by the model contain substantial amounts of variance at low frequencies. Long time-scale anomalies of soil moisture resemble the red noise response of the soil layer to white noise rainfall forcing. The dependence of the temporal variability of soil moisture on potential evaporation and precipitation is discussed. 相似文献
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Irimajiri Y. Manabe T. Ochiai S. Masuko H. Yamagami T. Saito Y. Izutsu N. Kawasaki T. Namiki M. Murata I. 《Geoscience and Remote Sensing Letters, IEEE》2006,3(1):88-92
A balloon-borne superconducting submillimeter-wave limb-emission sounder (BSMILES) was developed to observe thermal emission lines from stratospheric minor constituents. BSMILES carries a 300-mm-diameter offset parabolic antenna, a 624-639-GHz superconductor-insulator-superconductor (SIS) receiver, a three-axis fiber-optical gyroscope, and an acousto-optical spectrometer. BSMILES was launched from the Pacific Coast of Japan. All systems operated properly and emission line spectra of stratospheric gases, such as O/sub 3/, HCl, HO/sub 2/, and O/sub 3/ isotopes were measured. The system noise temperature in double sideband (DSB) during the flight was less than 460 K over the observing bandwidth with a best value of 330 K that is 11 times as large as the quantum limit (11h/spl nu//k/sub B/). After the observation, the gondola splashed down in the Pacific Ocean and was retrieved. Almost all instruments were waterproofed, and it has been proved that they are reusable. 相似文献
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The influence of continental ice,atmospheric CO2, and land albedo on the climate of the last glacial maximum 总被引：1，自引：0，他引：1
The contributions of expanded continental ice, reduced atmospheric CO2, and changes in land albedo to the maintenance of the climate of the last glacial maximum (LGM) are examined. A series of experiments is performed using an atmosphere-mixed layer ocean model in which these changes in boundary conditions are incorporated either singly or in combination. The model used has been shown to produce a reasonably realistic simulation of the reduced temperature of the LGM (Manabe and Broccoli 1985b). By comparing the results from pairs of experiments, the effects of each of these environmental changes can be determined.Expanded continental ice and reduced atmospheric CO2 are found to have a substantial impact on global mean temperature. The ice sheet effect is confined almost exclusively to the Northern Hemisphere, while lowered CO2 cools both hemispheres. Changes in land albedo over ice-free areas have only a minor thermal effect on a global basis. The reduction of CO2 content in the atmosphere is the primary contributor to the cooling of the Southern Hemisphere. The model sensitivity to both the ice sheet and CO2 effects is characterized by a high latitude amplification and a late autumn and early winter maximum.Substantial changes in Northern Hemisphere tropospheric circulation are found in response to LGM boundary conditions during winter. An amplified flow pattern and enhanced westerlies occur in the vicinity of the North American and Eurasian ice sheets. These alterations of the tropospheric circulation are primarily the result of the ice sheet effect, with reduced CO2 contributing only a slight amplification of the ice sheet-induced pattern. 相似文献
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The sensitivity of the global climate is essentially determined by the radiative damping of the global mean surface temperature
anomaly through the outgoing radiation from the top of the atmosphere (TOA). Using the TOA fluxes of terrestrial and reflected
solar radiation obtained from the Earth radiation budget experiment (ERBE), this study estimates the magnitude of the overall
feedback, which modifies the radiative damping of the annual variation of the global mean surface temperature, and compare
it with model simulations. Although the pattern of the annually varying anomaly is quite different from that of the global
warming, the analysis conducted here may be used for assessing the systematic bias of the feedback that operates on the CO2-induced warming of the surface temperature. In the absence of feedback effect, the outgoing terrestrial radiation at the
TOA is approximately follows the Stefan-Boltzmann’s fourth power of the planetary emission temperature. However, it deviates
significantly from the blackbody radiation due to various feedbacks involving water vapor and cloud cover. In addition, the
reflected solar radiation is altered by the feedbacks involving sea ice, snow and cloud, thereby affecting the radiative damping
of surface temperature. The analysis of ERBE reveals that the radiative damping is weakened by as much as 70% due to the overall
effect of feedbacks, and is only 30% of what is expected for the blackbody with the planetary emission temperature. Similar
feedback analysis is conducted for three general circulation models of the atmosphere, which was used for the study of cloud
feedback in the preceding study. The sign and magnitude of the overall feedback in the three models are similar to those of
the observed. However, when it is subdivided into solar and terrestrial components, they are quite different from the observation
mainly due to the failure of the models to simulate individually the solar and terrestrial components of the cloud feedback.
It is therefore desirable to make the similar comparison not only for the overall feedback but also for its individual components
such as albedo- and cloud-feedbacks. Although the pattern of the annually-varying anomaly is quite different from that of
global warming, the methodology of the comparative analysis presented here may be used for the identification of the systematic
bias of the overall feedback in a model. A proposal is made for the estimation of the best guess value of climate sensitivity
using the outputs from many climate models submitted to the Intergovernmental panel on Climate Change. 相似文献
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Tetsuya Nishikawa Yutaka Hori Satoshi Nagai Kazutaka Miyahara Yukinobu Nakamura Kazuhiro Harada Minoru Tanda Takehiko Manabe Kuninao Tada 《Estuaries and Coasts》2010,33(2):417-427
Long-term monitoring of water quality and phytoplankton was conducted at 19 sampling stations in Harima-Nada, eastern Seto Inland Sea, Japan for 35 years from 1973 to 2007. There were two significant long-term changes, an increase in winter water temperatures of 0.042°C year?1, and a decrease in dissolved inorganic nitrogen (DIN) from about 10 μM in the 1970s to ~5 μM in the late 1990s due to the reduction in nutrient inputs. DIN concentrations and total phytoplankton cell density were both higher during the 1970s to the early 1980s and then exhibited a significant decrease in the mid 1980s and remained relatively constant thereafter. Diatoms were the dominant phytoplankton group (>90%) over the 35-year period, and there was a dramatic shift from Skeletonema dominance (~70%) to Chaetoceros in the mid 1980s. This shift in diatom species may be attributed to differences in the life cycle of Skeletonema and Chaetoceros and the response to the decrease in DIN concentration. 相似文献
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Amirhomayoun Saffarzadeh Takayuki Shimaoka Hirofumi Nakayama Takao Hanashima Kentaro Yamaguchi Kazutoshi Manabe 《Natural Hazards》2017,88(3):1273-1295
The potential impacts of tsunamis along the Catalan Coast (NW Mediterranean) are analysed using numerical modelling. The region is characterized by moderate to low seismic activity and by moderate- to low-magnitude earthquakes. However, the occurrence of historical strong earthquakes and the location of several active offshore faults in front of the coast suggest that the possibility of an earthquake-triggered tsunami is not negligible although of low probability. Up to five faults have been identified to generate tsunamis, being the highest associated possible seismic magnitudes of up to 7.6. Coastal flooding and port agitation are characterized using the Worst-case Credible Tsunami Scenario Analysis approach. The results show a multiple fault source contribution to tsunami hazard. The shelf dimensions and the existence of submerged canyons control the tsunami propagation. In wide shelves, waves travelling offshore may become trapped by refraction causing the wave energy to reach the coastline at some distance from the origin. The free surface water elevation increases at the head of the canyons due to the sharp depth gradients. The effects of potential tsunamis would be very harmful in low-lying coastal stretches, such as deltas, with a high population concentration, assets and infrastructures. The Ebro delta appears to be the most exposed coast, and about the 20% of the delta surface is prone to flooding due to its extremely low-lying nature. The activity at Barcelona port will be severely affected by inflow backflow current at the entrance of up to 2 m/s. 相似文献