295 research outputs found
NATURAL VARIABILITY OF THE ATLANTIC MERIDIONAL OVERTURNING CIRCULATION IN THE INMCM3.0 MODEL
No full textNatural variability of the Atlantic Meridional Overturning Circulation (AMOC) in a 720-year pre-industrial simulation from the coupled climate model INMCM3.0 is analyzed. In the model, AMOC has the strongest spectral maximum at a period of 15 years. On the basis of a 5-year running mean AMOC index it is shown that the transition from negative to positive AMOC phase corresponds with high water density at 35-60N and low density at 15-25N, while during the positive
AMOC phase, density anomalies are weaker. A correspondence between the positive AMOC phase and positive Arctic Oscillation is identified. Positive, negative and delayed feedbacks between AMOC and surface heat and fresh water fluxes, and heat and salinity transport in the ocean are studied. The meridional oceanic fresh water flux is found to be mainly responsible for a positive feedback, while the meridional heat flux is a main factor for a delayed negative feedback for the AMOC variability
Mid Latitude Extreme Precipitation under future changed climate
No full textPrecipitation patterns under global warming scenario are statistically analyzed for the Mediterranean and North Europe areas. Simulation data from the global coupled atmosphere-ocean model INMCM.3 are used and compared with obervations.
Changes in intensity, frequency, duration and amount of precipitation due to different IPCC scenarios are investigated.
Furthermore we analyze the precipitation patterns for the better understanding of the hydrologic cycle, including a statistical analysis of precipitation extreme events
Anomaly of surface density 10<sup>−2</sup> kg m<sup>−3</sup> in January 1995 with respect to January 1979–2008 in SODA
No full text<p><strong>Figure 5.</strong> Anomaly of surface density 10<sup>−2</sup> kg m<sup>−3</sup> in January 1995 with respect to January 1979–2008 in SODA.</p> <p><strong>Abstract</strong></p> <p>Data from a 500-year preindustrial control run of climate model INMCM4 show distinct climate variability in the Arctic and North Atlantic with a period of 35–50 years. The variability can be seen as anomalies of upper ocean density that appear in the Arctic and propagate to the North Atlantic. The density gradient in a northeast–southwest direction alternates with the density gradient in a northwest–southeast direction. A positive density anomaly in the Arctic is associated with a positive salinity anomaly, a positive surface temperature anomaly and a reduction of sea ice in the Barents and Kara Seas. The nature of the variability is a vertical advection of density by thermal currents similar to that proposed in Dijkstra <em>et al</em> (2008 <em>Phil. Trans. R. Soc.</em> A <strong>366</strong>). The cycle of model variability shows that after a negative anomaly of density in the northwest Atlantic, one should expect warming in the Arctic in 5–10 years. The ensemble of decadal predictions with climate model INMCM4 starting from 1995 shows that warming in the western Arctic and especially in the Barents Sea observed in 1996–2010 can be reproduced by eight of ten ensemble members. Arctic climate predictability in this case is associated with a proposed mechanism of a 35–50 year North Atlantic–Arctic oscillation.</p
Some limit theorems for -pairwise negative quadrant dependent random variables
Get PDFsummary:The authors first establish the Marcinkiewicz-Zygmund inequalities with exponent () for -pairwise negatively quadrant dependent (-PNQD) random variables. By means of the inequalities, the authors obtain some limit theorems for arrays of rowwise -PNQD random variables, which extend and improve the corresponding results in [Y. Meng and Z. Lin (2009)] and [H. S. Sung (2013)]. It is worthy to point out that the open problem of [H. S. Sung, S. Lisawadi, and A. Volodin (2008)] can be solved easily by using the obtained inequality in this paper
A composite of the difference of ocean current anomalies, cm s<sup>−1</sup> at 0 and 100 m for year −10 (top) and year 0 (bottom)
No full text<p><strong>Figure 4.</strong> A composite of the difference of ocean current anomalies, cm s<sup>−1</sup> at 0 and 100 m for year −10 (top) and year 0 (bottom).</p> <p><strong>Abstract</strong></p> <p>Data from a 500-year preindustrial control run of climate model INMCM4 show distinct climate variability in the Arctic and North Atlantic with a period of 35–50 years. The variability can be seen as anomalies of upper ocean density that appear in the Arctic and propagate to the North Atlantic. The density gradient in a northeast–southwest direction alternates with the density gradient in a northwest–southeast direction. A positive density anomaly in the Arctic is associated with a positive salinity anomaly, a positive surface temperature anomaly and a reduction of sea ice in the Barents and Kara Seas. The nature of the variability is a vertical advection of density by thermal currents similar to that proposed in Dijkstra <em>et al</em> (2008 <em>Phil. Trans. R. Soc.</em> A <strong>366</strong>). The cycle of model variability shows that after a negative anomaly of density in the northwest Atlantic, one should expect warming in the Arctic in 5–10 years. The ensemble of decadal predictions with climate model INMCM4 starting from 1995 shows that warming in the western Arctic and especially in the Barents Sea observed in 1996–2010 can be reproduced by eight of ten ensemble members. Arctic climate predictability in this case is associated with a proposed mechanism of a 35–50 year North Atlantic–Arctic oscillation.</p
Status of the ITER Divertor IVT procurement
No full textThe Ansaldo Nucleare (ANN) Prototype manufacturing is under completion. The stainless steel support structure was manufactured by Walter Tosto (Italy) and the Plasma Facing Units (PFUs) were manufactured by ENEA (Italy) by diffusion bonding between the CuCrZr pipe and the W monoblocks equipped with a pure Cu compliance layer (Hot Radial Pressing, HRP). This paper presents some of the learnings of the Inner Vertical Target (IVT) Prototype manufacturing and provides the main results of the dimensional control tests. The outcomes of the PFUs High Heat Flux (HHF) testing performed in the ITER Divertor Test Facility (IDTF) in Efremov institute, Saint Petersburg (Russia) are presented as well
Lower bounds for average sample size and efficiency of sequential selection procedures
Get PDFIn this paper we establish lower bounds for average sample size in procedures for selecting a population with the largest value of scalar parameter, when the given probability of the correct solution is guaranteed. In construction of bounds we use universal bounds of Volodin and Malyutov [I. N. Volodin, Theory Probab. Appl., 24 (1979), pp. 120-129], [M. B. Malyutov, Izv. Vyssh. Uchebn. Zaved. Mat., 1983, no. 11, pp. 19-41 (in Russian)]. The obtained results are applied to the estimation of efficiency of the Bechhofer selection procedure [R. E. Bechhofer, Ann. Math. Statist., 25 (1954), pp. 16-39] and sequential modification of it [S. C. Kao and T. L. Lai, Comm. Statist. A-Theory Methods, 9 (1980), pp. 1657-1676], [R. E. Bechhofer, J. Kiefer, and M. Sobel, Sequential Identification and Ranking Procedures, with Special Reference to Koopman-Darmois Populations, University of Chicago Press, Chicago, 1968]. ©2013 Society for Industrial and Applied Mathematics
A composite of the anomalies of surface density 10<sup>−2</sup> kg m<sup>−3</sup> (left) and near-surface air temperature, <em>K</em> (right), for year −10, −5, 0, 5 and 10
No full text<p><strong>Figure 2.</strong> A composite of the anomalies of surface density 10<sup>−2</sup> kg m<sup>−3</sup> (left) and near-surface air temperature, <em>K</em> (right), for year −10, −5, 0, 5 and 10.</p> <p><strong>Abstract</strong></p> <p>Data from a 500-year preindustrial control run of climate model INMCM4 show distinct climate variability in the Arctic and North Atlantic with a period of 35–50 years. The variability can be seen as anomalies of upper ocean density that appear in the Arctic and propagate to the North Atlantic. The density gradient in a northeast–southwest direction alternates with the density gradient in a northwest–southeast direction. A positive density anomaly in the Arctic is associated with a positive salinity anomaly, a positive surface temperature anomaly and a reduction of sea ice in the Barents and Kara Seas. The nature of the variability is a vertical advection of density by thermal currents similar to that proposed in Dijkstra <em>et al</em> (2008 <em>Phil. Trans. R. Soc.</em> A <strong>366</strong>). The cycle of model variability shows that after a negative anomaly of density in the northwest Atlantic, one should expect warming in the Arctic in 5–10 years. The ensemble of decadal predictions with climate model INMCM4 starting from 1995 shows that warming in the western Arctic and especially in the Barents Sea observed in 1996–2010 can be reproduced by eight of ten ensemble members. Arctic climate predictability in this case is associated with a proposed mechanism of a 35–50 year North Atlantic–Arctic oscillation.</p
Lower bounds for average sample size and efficiency of sequential selection procedures
No full textIn this paper we establish lower bounds for average sample size in procedures for selecting a population with the largest value of scalar parameter, when the given probability of the correct solution is guaranteed. In construction of bounds we use universal bounds of Volodin and Malyutov [I. N. Volodin, Theory Probab. Appl., 24 (1979), pp. 120-129], [M. B. Malyutov, Izv. Vyssh. Uchebn. Zaved. Mat., 1983, no. 11, pp. 19-41 (in Russian)]. The obtained results are applied to the estimation of efficiency of the Bechhofer selection procedure [R. E. Bechhofer, Ann. Math. Statist., 25 (1954), pp. 16-39] and sequential modification of it [S. C. Kao and T. L. Lai, Comm. Statist. A-Theory Methods, 9 (1980), pp. 1657-1676], [R. E. Bechhofer, J. Kiefer, and M. Sobel, Sequential Identification and Ranking Procedures, with Special Reference to Koopman-Darmois Populations, University of Chicago Press, Chicago, 1968]. ©2013 Society for Industrial and Applied Mathematics
A non-invasive capacitive sensor strip for aerodynamic pressure measurement
Get PDFThis paper presents a capacitive pressure sensor strip implemented in general purpose printed circuit board (PCB) technology based on a thin 3D structure composed of polyimide, woven glass reinforced epoxy resin (FR4) and metal layers. Multiphysics finite elements method (FEM) simulations have been performed over the proposed structure in order to develop a time-dependent electrical and mechanical model that can be easily used to tailor the characteristics to the application. The device targets a wide class of fluid dynamics applications, being non-invasive, comformable and smart for placement. The device simulations are herein validated by experimental wind tunnel measurements and compared with figures obtained on a wing profile by conventional electromechanical pressure transducers. This approach is one of the first example of fully embedding and electronically controlled fluid flow monitoring apparatus that could be used in replacement of state of the art mechanical systems
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