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Michael C. Coniglio, James Correia Jr., Patrick T. Marsh, and Fanyou Kong

1. Introduction Planetary boundary layer (PBL) schemes that parameterize vertical turbulent fluxes of heat, moisture, and momentum in the atmosphere are required in current operational numerical weather prediction (NWP) models because their grid spacing is coarse relative to the spatial and temporal scales of turbulence. This includes convection-allowing NWP models because the horizontal length scales of the largest eddies are typically smaller than the grid spacing (1–4 km). Uncertainty and

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Pengyuan Li, Gang Fu, Chungu Lu, Dan Fu, and Shuai Wang

. 2006 ; Gao et al. 2007 ), climatology ( S. Zhang et al. 2009 ), and large-scale environmental factors ( Li et al. 2011 ). However, the detailed formation mechanism of fogs over the YS has not been discussed sufficiently, especially for situations in which low-level jets (LLJs) come into play. Fogs over the YS typically form under a stably stratified atmosphere. The vertical mixing process triggered mainly by the turbulence in the stably stratified atmosphere may be the dominant process in the

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Nicholas A. Bond and Gabriel A. Vecchi

. J. Climate , 13 , 793 – 820 . 10.1175/1520-0442(2000)013<0793:EPEITW>2.0.CO;2 Horel, J. H. , and Wallace J. M. , 1981 : Planetary scale atmospheric phenomenon associated with the Southern Oscillation. Mon. Wea. Rev. , 109 , 813 – 829 . 10.1175/1520-0493(1981)109<0813:PSAPAW>2.0.CO;2 Hoskins, B. J. , and Karoly D. J. , 1981 : The steady linear response of a spherical atmosphere to thermal and orographic forcing. J. Atmos. Sci. , 38 , 1179 – 1196 . 10

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Paul J. Roebber, James M. Frederick, and Thomas P. DeFelice

, Third Symp. on Atmospheric Turbulence and Air Quality, Raleigh, NC, Amer. Meteor. Soc., 46–49. ——, 1979: High resolution models of the planetary boundary layer. Advances in Environmental Science and Engineering, J. R. Pfafflin and E. N. Ziegler, Eds., Gordon and Breach, 50–85. ——, 1997: Turbulence and Diffusion in the Atmosphere: Lectures in Environmental Sciences. Springer-Verlag, 185 pp. Bosart, L. F., and F. Sanders, 1981: The Johnstown flood of July 1977:A long-lived convective system

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Xu Zhang, Yuhua Yang, Baode Chen, and Wei Huang

, the total flux from the two components remains approximately unchanged regardless of resolution, but contributions from the resolved and parameterized components may vary greatly (with the latter decreasing with an increase in resolution). Assuming that the subgrid-scale flux due to turbulence mixing is negligible above the planetary boundary layer, the total flux for a conservative variable or water species φ can be decomposed into flux owing to the resolved grid-mean flow and flux due to

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Dongliang Wang, Xudong Liang, Ying Zhao, and Bin Wang

1. Introduction One of the main problems in the numerical prediction of tropical cyclones (TCs) is the difficulty in specifying the dynamical and thermodynamical structures of the atmosphere near the TC center and in the surrounding environment because of sparse conventional observations over the ocean. Even with increased satellite and radar data, the use of bogus vortices in the analysis of an operational numerical TC prediction model is often adopted in order to improve the TC representation

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John A. Knaff, Thomas A. Cram, Andrea B. Schumacher, James P. Kossin, and Mark DeMaria

) easterly winds and colder-than-average temperatures at 200 hPa, 3) a specific range (25.4°–28.5°C) of sea surface temperatures (SSTs) with small variations along the storm track, and 4) a lack of 200-hPa relative eddy flux convergence due to interactions with the environmental flow. Weak easterly shear is hypothesized to promote the symmetric nature of AHs by canceling the effect of vertical wind shear induced by the vortex interacting with gradients of planetary vorticity. With respect to maximum wind

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Robert R. Gillies, Shih-Yu Wang, and Marty R. Booth

-simulated westward-propagating, planetary-scale fluctuations with approximately three-week periods. Mon. Wea. Rev. , 127 , 2324 – 2345 . 10.1175/1520-0493(1999)127<2324:OAGSWP>2.0.CO;2 Lockhart, W. M. , 1943 : A winter fog in the interior. Characteristic Weather Phenomena of California, MIT Meteorological Papers, Vol. 1, No. 2, 11–20 . Madden, R. A. , and Julian P. R. , 2005 : Historical perspective. Intraseasonal Variability in the Atmosphere–Ocean Climate System, K.-M. Lau and D. E. Waliser

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Xiaohui Shi, Xiangde Xu, and Chungu Lu

, Huang et al. (2007) suggested that the winter stationary planetary wave played an important role in the variation of the East Asian winter monsoon. Some synoptic studies for China winter snowstorms began to occur in the 1970s. Wang and Xu (1979) first investigated China’s Inner Mongolia “77.10” extraordinary snowstorm. They proposed a “north ridge–south trough” antiphased conceptual model for snowstorms in northern China. Gong and Li (2001) analyzed the relationship between Inner Mongolian

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David R. Bright and Steven L. Mullen

, and are therefore well suited for parameterizing the effects of large eddies in an unstable, convective PBL. Local schemes have been extended to third order, while nonlocal schemes have been limited to first order ( Garratt 1992 ). See Stull (1988 , chapter 6) for a mathematically based discussion on turbulent closure. c. Planetary boundary layers in complex terrain Anticipating changes in the structure of the PBL is further complicated by vertical growth into a layer of the free atmosphere

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