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Joseph Egger and H-D. Schilling

1 MARCH 1984 JOSEPH EGGER AND H.-D. SCHILLING 779Stochastic Forcing of Planetary Scale Flow JOSEPH EGGER AND H.-D. SCHILLINGMeteorologisches Institut der Universitiit Miinchen, Munich, FRG(Manuscript received and in final form 12 October 1983) ABSTRACT Using geopotential height observations we analyze the fluctuations of the barotropic

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Leong Wai Siu and Kenneth P. Bowman

) demonstrated the importance of diabatic heating in simulating the NAMA using a mesoscale numerical model. Chao and Chen (2001) asserted that land–sea contrasts and orography are important for simulating the North American monsoon. Other thermal forcings may also be important. The heaviest North American monsoon precipitation is located along the Sierra Madre Occidental in northwestern Mexico; however, the heaviest precipitation in the western Hemisphere (WH) falls in the equatorial Pacific and Atlantic

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R. J. Haarsma and J. D. Opsteegh

Utrecht, Utrecht, The Netherlands (Manuscript received 12 October 1988, in final form I0 April 1989) We have investigated the nonlinear steady-state response of a barotropic model to an estimate of the observedanomalous tropical divergence forcing for the El Nifio winter of 1982/83, The 400 mb climatological fl0w wasmade a forced solution of the model by adding a relaxation forcing. The Rayleigh friction coefficient (~-~ -- 20days) was chosen such that this solution is marginally stable. The

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Andrew J. Majda, Boris Gershgorin, and Yuan Yuan

1. Introduction The low-frequency response to changes in external forcing or other parameters for various components of the climate system is a central problem of contemporary climate change science. Examples include the response of the mean and variance of the low-frequency teleconnection patterns of the atmosphere in addition to more familiar functions such as the mean temperature response in a global warming scenario. Leith (1975) suggested that if the climate system satisfied a suitable

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Edwin K. Schneider, Lennart Bengtsson, and Zeng-Zhen Hu

between the simulated and observed low-pass evolution of the wintertime NAO index, including a positive trend, at least for the mid-1960s through the mid-1990s. Rodwell et al. (1999) relate this resemblance to forcing by North Atlantic SST anomalies (SSTAs) and find no evidence for tropical forcing. Hoerling et al. (2001) find the forcing from the extratropics and the tropical Atlantic to be small and therefore attribute the resemblance in the low-frequency behavior and trend of an index closely

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Mauro Dall’Amico and Joseph Egger

noise forcing as a data basis ( section 3 ). Systematic variations of grid size, time series length, sampling interval, and the number of variables are conducted in section 4 in order to study their effect on how well the EME reproduces the dynamics of the studied system. The conclusions are outlined in section 5 . The results of this part of the paper provide guidelines for the application of this methodology to any problem in (and beyond) the atmospheric sciences. Real data of limited length

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J. C. Alpert and S. K. Avery

OCTOBER 19~3 J.C. ALPERT, M. A. GELLER AND S. K. AVERY 2467'The Response of Stationary Planetary Waves to Tropospheric Forcing~ J. C. ALPERT AND M. A. GELLERLaboratory for Planetary Atmospheres, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 S. K. AVERY2Department of Electrical Engineering, University of Illinois, Urbana 61801(Manuscript received 2 February 1983, in final

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Steven L. Mullen

VOL. 44, NO. 1 JOURNAL OF THE ATMOSPHERIC SCIENCES I JANUARY 1987 Transient Eddy Forcing of Blocking Flows STEVEN L. MULLEN* National Center for Atmospheric Research,** Boulder, CO 80307 (Manuscript received 2 January 1986, in final form 1 July 1986) ABSTRACT The net forcing of blocking flows by transient eddies having synoptic time scales is examined within

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Brian F. Farrell and Petros J. Ioannou

1. Introduction A comprehensive understanding of the dynamics of linear systems is fundamental to physical science and, while linear systems arise in a wide variety of contexts, in this work we have in mind the particular examples of the dynamics of perturbations to the tangent linear forecast and data assimilation error systems. Among important problems in dynamical system theory is understanding the response of a linear system to forcing distributed in time. In the context of linear forecast

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Le Kuai, Run-Lie Shia, Xun Jiang, Ka Kit Tung, and Yuk L. Yung

period of the QBO averages about 28 months but is known to have interannual variations of a few months about the average. While it is not surprising for this phenomenon arising from wave–mean flow interaction to have a variable period, the possibility that it could be affected by external forcing such as the 11-yr solar cycle (SC) is intriguing. Using radiosonde data from the Free University of Berlin (FUB) near the equator at 45 hPa between 1956 and 1996, Salby and Callaghan (2000) found that the

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