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Song-You Hong, Jung Choi, Eun-Chul Chang, Hoon Park, and Young-Joon Kim

1. Introduction At present, global numerical weather prediction models run with horizontal resolutions that cannot typically resolve atmospheric phenomena smaller than about 10–100 km. Many atmospheric processes have shorter horizontal scales than these scales and some of these “subgrid scale” processes interact with one another and affect the larger-scale atmosphere in important ways. Atmospheric gravity waves are one such unresolved process. The dissipation of these waves produces synoptic

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Hui Li, Panmao Zhai, Yang Chen, and Er Lu

atmospheric circulation play important roles in the distribution and maintenance of the monsoon rain belt in China. The study of teleconnection patterns in summer began with Nitta (1987) and Huang and Li (1987) , who proposed the concepts of the East Asia–Pacific (EAP) teleconnection and the Pacific–Japan (P–J) teleconnection—two patterns that are essentially the same. They both pointed out that the relationship between East Asian climate and northwestern Pacific climate is established by

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Roger Rodrigues Torres and Nelson Jesus Ferreira

. Ferreira et al. (1990) identified the occurrence of easterly wave disturbances (EWDs) in the wind field, which propagated westward over the tropical South Atlantic Ocean during the austral autumn and winter. When these disturbances interact with local circulations, low-level convergence increases, causing strong rainfall on the eastern and northern NEB coasts. Although EWDs occur in several tropical regions, they are more frequently observed in the Northern Hemisphere. Therefore, more attention has

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Bo Zhang, Ge Liu, Yuejian Zhu, and Ning Shi

MLRYR during the whole summer, and during each month of the summer season. Blocking is one of the most important atmospheric circulation systems at middle and high latitudes, contributing to weather anomalies over different regions during different seasons, such as large-range cold waves ( Cattiaus et al. 2010 ; Buehler et al. 2011 ; Pfahl and Wernli 2012 ; Ye et al. 2015 ; Brunner et al. 2017 ) and heatwaves ( Dole et al. 2011 ; Matsueda 2011 ; Hoskins and Woollings 2015 ; Horton et al. 2016

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Gui-Ying Yang, Samantha Ferrett, Steve Woolnough, John Methven, and Chris Holloway

simulations was shown to lead to a significant improvement in the representation of equatorial Kelvin waves ( Walters et al. 2017 ). While the atmospheric model version is consistent during this period there was a change from N768 (~17 km) resolution to N1280 (~10 km) resolution in mid-2017; an upgrade to the land surface model in late 2018; and a number of changes to both the data-assimilation system and assimilated observations during the period. The horizontal wind components and geopotential height

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Robert S. Ross, T. N. Krishnamurti, S. Pattnaik, and A. Simon

1. Introduction African easterly waves (AEWs) are known to play a significant role in the development of Atlantic tropical cyclones. Avila et al. (2000) found that on average 62% of all Atlantic tropical depressions develop from AEWs. From June through October of the 1996 season Avila et al. tracked 62 AEWs. Only 12 of these waves developed into tropical depressions, but all 12 of these became named systems. It is evident that a majority of AEWs never develop beyond the wave stage, but that

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Peter A. E. M. Janssen, Björn Hansen, and Jean-Raymond Bidlot

were using modeled wave heights for 1988 obtained from cycle 2 of WAM, while the forcing wind fields were provided by the T106/19L version of the ECMWF atmospheric model. Since 1988 a number of important changes have been introduced in the wind–wave forecasting system at ECMWF. First of all, in September 1991 the resolution of ECMWF’s atmospheric model was doubled in the horizontal and nearly doubled in the vertical. Because of the increased horizontal resolution, one would expect a better

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Russell S. Schneider

December 1987 several long-lived, large-amplitude mesoscale wave disturbances embedded within a rapidly intensifying extratropical cyclone traversed the Midwest and created life-threatening blizzard conditions. Within the wave disturbances, which likely were atmospheric gravity waves, pressure falls of up to 11 mb in 15 min were accompanied by winds in excess of 30 m s-~ (60 kt), cloud-to-ground lightning and heavy snowfall. One of the large-amplitude mesoseate wave disturbances, characterized by a

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Jose-Henrique G. M. Alves, Arun Chawla, Hendrik L. Tolman, David Schwab, Gregory Lang, and Greg Mann

, providing accurate forecasts of wind waves is a critical service toward ensuring the safety of maritime operations in the Great Lakes, with consequences of great importance to the American economy and public safety. Since 1974, marine forecasting in the Great Lakes region has been made in a systematic way following the creation of the National Oceanic and Atmospheric Administration’s (NOAA) Great Lakes Environmental Research Laboratory (GLERL). GLERL developed technology for producing wave forecasts for

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Rosmeri Porfírio da Rocha, Shigetoshi Sugahara, and Reinaldo Bonfim da Silveira

cyclones in the South Atlantic Ocean occurring between April and September 1999. The hindcasts were conducted using the WAVEWATCH III model with surface forcing provided by the 10-m above ground level wind field of the NCEP– NCAR reanalysis. The significant wave height hindcasts were evaluated against altimetry observations from TOPEX. The paper is organized as follows. Section 2 describes the atmospheric and oceanic datasets used in the analysis. A brief meteorological description of the mean

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