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1.
Tatsuya?IwataEmail author Yoshiko?Shinomura Yuta?Natori Yasumasa?Igarashi Rumi?Sohrin Yoshimi?Suzuki 《Journal of Oceanography》2005,61(4):721-732
We investigated the water structure and nutrient distribution in the Suruga Bay from April 2000 to July 2002, especially the Offshore Water, which occupies a large part of the bay. The maximum salinity in the upper 200 m varied between 34.49 and 34.71, indicating a temporal change in the influence of Kuroshio Water on the Offshore Water. Seasonal variation in nutrient concentrations was largest from surface to 50 m. On the other hand, the variance in nutrient concentrations within each season was largest in the subsurface layer of 100–300 m in spring, summer and fall. In the Offshore Water, the change of nutrients was negatively correlated with that of salinity in each season. This suggests that an increasing intrusion of saline water brings about a lower nutrient concentration in the Offshore Water. Likewise, negative correlations were observed between the change of the maximum salinity and chlorophyll a (Δ [chl.a-int])/nutrients integrated in the upper 200 m. Δ[chl.a-int] was significantly correlated with the changes of nitrate and phosphorus, but there were no significant correlations between Δ[chl.a-int] and the change of silicate. These results suggest that the concentrations of chlorophyll a and nutrients in the Offshore Water were decreased due to the increasing intrusion of Kuroshio Water. The Offshore Water is likely to be related to the regulation of primary production by nitrate. 相似文献
2.
Mingyu Wu Quanming Lu Martin Volwerk Rumi Nakamura Tielong Zhang 《Astrophysics and Space Science》2018,363(2):22
In this paper, with the in-situ observations from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes we report a wavy dipolarization front (DF) event, where the DF has different magnetic structures and electron distributions at different \(y\) positions in the Geocentric Solar Magnetospheric (GSM) coordinates. At \(y \sim2.1R_{E}\) (\(R_{E}\) is the radius of Earth), the DF has a relatively simple structure, which is similar to that of a conventional DF. At \(y \sim3.0R_{E}\), the DF is revealed to have a multiple DF structure, where the plasma exhibits a vortex flow. Such a wavy DF could be the results of the interchange instability. The different structure of such a wavy DF at different sites has a great effect on electron acceleration. Fermi acceleration can occur at the site of the DF with a simple or multiple DF structure, while betatron acceleration as a local process has the contribution to energetic electrons only at the site of the DF with a simple structure. 相似文献
3.
Past and future polar amplification of climate change: climate model intercomparisons and ice-core constraints 总被引:1,自引:0,他引:1
V. Masson-Delmotte M. Kageyama P. Braconnot S. Charbit G. Krinner C. Ritz E. Guilyardi J. Jouzel A. Abe-Ouchi M. Crucifix R. M. Gladstone C. D. Hewitt A. Kitoh A. N. LeGrande O. Marti U. Merkel T. Motoi R. Ohgaito B. Otto-Bliesner W. R. Peltier I. Ross P. J. Valdes G. Vettoretti S. L. Weber F. Wolk Y. Yu 《Climate Dynamics》2006,27(4):437-440
4.
Studies of climate change 6,000 years before present using atmospheric general circulation models (AGCMs) suggest the enhancement
and northward shift of the summer Asian and African monsoons in the Northern Hemisphere. Although enhancement of the African
monsoonal precipitation by ocean coupling is a common and robust feature, contradictions exist between analyses of the role
of the ocean in the strength of the Asian monsoon. We investigated the role of the ocean in the Asian monsoon and sought to
clarify which oceanic mechanisms played an important role using three ocean coupling schemes: MIROC, an atmosphere–ocean coupled
general circulation model [C]; an AGCM extracted from MIROC coupled with a mixed-layer ocean model [M]; and the same AGCM,
but with prescribed sea surface temperatures [A]. The effect of “ocean dynamics” is quantified through differences between
experiments [C] and [M]. The effect of “ocean thermodynamics” is quantified through differences between experiments [M] and
[A]. The precipitation change for the African and Asian monsoon area suggested that the ocean thermodynamics played an important
role. In particular, the enhancement of the Asian monsoonal precipitation was most vigorous in the AGCM simulations, but mitigated
in early summer in ocean coupled cases, which were not significantly different from each other. The ocean feedbacks were not
significant for the precipitation change in late summer. On the other hand, in Africa, ocean thermodynamics contributed to
the further enhancement of the precipitation from spring to autumn, and the ocean dynamics had a modest impact in enhancing
precipitation in late summer. 相似文献
5.
Estimation of specific yields of individual litho-units in a terrain with multiple litho-units: A water balance approach 总被引:1,自引:0,他引:1
Ranjan Kumar Ray Arunangshu Mukherjee Rumi Mukherjee 《Journal of the Geological Society of India》2014,84(2):221-226
In a terrain with more than one litho-unit, the traditional water balance approach provides a single spatially averaged specific yield. A methodology is proposed here, which can be applied to estimate specific yields of individual litho-units in such terrains. This approach is demonstrated here considering two watersheds, which are covered partly by limestone and partly by sandstone. Watershed wise specific yields were estimated using a traditional water balance method. The specific yields thus obtained are the volume-weighted averages of the specific yields of the individual litho-units in the watersheds. Based on the volumes of aquifers desaturated and the watershed wise specific yield values, a set of two linear equations in two variables was formulated. These linear equations were solved to get the specific yields of the individual litho-units. Specific yields of sandstone (Chandarpur Group) and limestone (Charmuria Formation) units in the study area were thus estimated to be 0.004 and 0.037 respectively. 相似文献
6.
Though several alternatives/modifications to the Piper diagram are available, the Piper diagram is still the most common way of representing chemical analyses. The present note shows how to reproduce the Piper trilinear diagram in rectangular coordinates retaining all the essential features of the trilinear diagram. In this form, it can be generated using commonly used graphics packages without requiring specialized software. A sample data set of six samples from Gurur watershed, Chhattisgarh, India, was used to illustrate the method. The patterns of points produced in the trilinear Piper diagram and the reproduced Piper diagram in rectangular coordinates are essentially identical. 相似文献
7.
Maisa Rojas Patricio Moreno Masa Kageyama Michel Crucifix Chris Hewitt Ayako Abe-Ouchi Rumi Ohgaito Esther C. Brady Pandora Hope 《Climate Dynamics》2009,32(4):525-548
The Southern Hemisphere westerly winds are an important component of the climate system at hemispheric and global scales.
Variations in their intensity and latitudinal position through an ice-age cycle have been proposed as important drivers of
global climate change due to their influence on deep-ocean circulation and changes in atmospheric CO2. The position, intensity, and associated climatology of the southern westerlies during the last glacial maximum (LGM), however,
is still poorly understood from empirical and modelling standpoints. Here we analyse the behaviour of the southern westerlies
during the LGM using four coupled ocean-atmosphere simulations carried out by the Palaeoclimate Modelling Intercomparison
Project Phase 2 (PMIP2). We analysed the atmospheric circulation by direct inspection of the winds and by using a cyclone
tracking software to indicate storm tracks. The models suggest that changes were most significant during winter and over the
Pacific ocean. For this season and region, three out four models indicate decreased wind intensities at the near surface as
well as in the upper troposphere. Although the LGM atmosphere is colder and the equator to pole surface temperature gradient
generally increases, the tropospheric temperature gradients actually decrease, explaining the weaker circulation. We evaluated
the atmospheric influence on the Southern Ocean by examining the effect of wind stress on the Ekman pumping. Again, three
of the models indicate decreased upwelling in a latitudinal band over the Southern Ocean. All models indicate a drier LGM
than at present with a clear decrease in precipitation south of 40°S over the oceans. We identify important differences in
precipitation anomalies over the land masses at regional scale, including a drier climate over New Zealand and wetter over
NW Patagonia. 相似文献
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