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M. Haeffelin, S. Crewell, A. J. Illingworth, G. Pappalardo, H. Russchenberg, M. Chiriaco, K. Ebell, R. J. Hogan, and F. Madonna

instruments to monitor physical processes in the atmospheric column. A large research community of observation experts and climate modelers was funded to exploit the observation data. Similar atmospheric profiling observation facilities associated with large scientific communities emerged in Europe at the end of the 1990s. Several European initiatives were triggered or encouraged through bilateral collaborations between U.S. and European Union (EU) scientists or through participation of EU scientists in

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Thomas J. Galarneau Jr.,, Lance F. Bosart, and, and Anantha R. Aiyyer

Abstract

The pioneering large-scale studies of cyclone frequency, location, and intensity conducted by Fred Sanders prompt similar questions about lesser-studied anticyclone development. The results of a climatology of closed anticyclones (CAs) at 200, 500, and 850 hPa, with an emphasis on the subtropics and midlatitudes, is presented to assess the seasonally varying distribution and hemispheric differences of these features. To construct the CA climatology, a counting program was applied to twice-daily 2.5° NCEP–NCAR reanalysis 200-, 500-, and 850-hPa geopotential height fields for the period 1950–2003. Stationary CAs, defined as those CAs that were located at a particular location for consecutive time periods, were counted only once.

The climatology results show that 200-hPa CAs occur preferentially during summer over subtropical continental regions, while 500-hPa CAs occur preferentially over subtropical oceans in all seasons and over subtropical continents in summer. Conversely, 850-hPa CAs occur preferentially over oceanic regions beneath upper-level midocean troughs, and are most prominent in the Northern Hemisphere, and over midlatitude continents in winter.

Three case studies of objectively identified CAs that produced heal waves over the United States, Europe, and Australia in 1995, 2003, and 2004, respectively, are presented to supplement the climatological results. The case studies, examining the subset of CAs than can produce heat waves, illustrate how climatologically hot continental tropical air masses produced over arid and semiarid regions of the subtropics and lower midlatitudes can become abnormally hot in conjunction with dynamically driven upper-level ridge amplification. Subsequently, these abnormally hot air masses are advected downstream away from their source regions in conjunction with transient disturbances embedded in anomalously strong westerly jets.

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Harold E. Brooks, Charles A. Doswell III, Xiaoling Zhang, A. M. Alexander Chernokulsky, Eigo Tochimoto, Barry Hanstrum, Ernani de Lima Nascimento, David M. L. Sills, Bogdan Antonescu, and Brad Barrett

’s forecasting was the source for some important developments in statistical verification of his forecasts ( Murphy 1996 ). By the end of the period leading up to 1917, the first efforts at a systematic understanding of what we now know as synoptic meteorology were undertaken at the so-called Bergen School, founded in 1917. That year also is marked by the publication of Wind- und Wasserhosen in Europa ( Wegener 1917 ), a compilation of known European tornadoes throughout history and a summary of previous

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Robert G. Ellingson, Robert D. Cess, and Gerald L. Potter

intercomparison studies to the establishment of ARM, a summary of each of the studies and their findings is provided below. 2. ICRCCM The Intercomparison of Radiation Codes used in Climate Models (ICRCCM) resulted from the unification of independent U.S. and European projects begun almost simultaneously in 1982. Frederick Luther initiated a comparison study of longwave radiative transfer models for the DOE’s Carbon Dioxide Research Division. In Europe, Yves Fouquart and Jean-Francois Gelyn proposed a model

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Maike Ahlgrimm, Richard M. Forbes, Jean-Jacques Morcrette, and Roel A. J. Neggers

1. Introduction The European Centre for Medium-Range Weather Forecasts (ECMWF) is one of the leading centers in operational global numerical weather prediction (NWP) and provides forecasts for days to monthly and seasonal time scales across a range of resolutions. Parameterization of subgrid physical processes are a key part of the model [the Integrated Forecast System (IFS)] and, for global application, must be appropriate for all meteorological regimes and regions across a wide range of

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Thomas P. Ackerman, Ted S. Cress, Wanda R. Ferrell, James H. Mather, and David D. Turner

needed to be done to promote the use of ARM data in the parameterization problem and that ARM science funding could not be stretched much further. One largely unexpected development that occurred in the late 1990s was the use of ARM data for evaluation of weather forecasting models, led particularly by the European Center for Medium-Range Weather Forecasts (ECMWF). After consultation with leadership at the National Centers for Environmental Prediction (NCEP) and ECMWF, ARM decided to fund a

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Sue Ellen Haupt, Steven Hanna, Mark Askelson, Marshall Shepherd, Mariana A. Fragomeni, Neil Debbage, and Bradford Johnson

large cities. Other European scholars including Kratzer (1937 , 1956 ) supported Horton’s observations, and Landsberg (1956) further affirmed the hypothesis. A landmark set of experiments, including the Metropolitan Meteorological Experiment (METROMEX; Braham 1981 ; Changnon 1981 ), executed in the 1970s confirmed that cities modify the spatiotemporal distribution of rainfall. However, Lowry (1998) challenged some of the underlying findings and experimental designs. In response to Lowry

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David M. Schultz, Lance F. Bosart, Brian A. Colle, Huw C. Davies, Christopher Dearden, Daniel Keyser, Olivia Martius, Paul J. Roebber, W. James Steenburgh, Hans Volkert, and Andrew C. Winters

arrival of Carl-Gustaf Rossby to the United States in 1926, the ascent to leadership of the Bureau by Bergen-trained Francis Reichelderfer in 1938, and the subsequent birth of meteorology programs at U.S. universities during World War II helmed by Bergen-trained academics, polar-front theory established stronger roots within the U.S. meteorological community ( Bornstein 1981 ; Namias 1981 , 1983 ; Newton and Rodebush Newton 1999 ). Similarly, resistance occurred in Europe. The United Kingdom also

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Stanley G. Benjamin, John M. Brown, Gilbert Brunet, Peter Lynch, Kazuo Saito, and Thomas W. Schlatter

continental Europe except not-plotted decrypted data per Lewis (1985 )], one from the Germans (no data over the British Isles), and one from a recent reanalysis by the European Centre for Medium-Range Weather Forecasts (ECMWF). All three showed a low in the North Sea, but the Allies had additional upstream observations and had earlier predicted that a gap would occur on 6 June with less cloud cover and wind. Even among the three Allied forecasting subteams (Met Office including Petterssen, Royal Navy

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J. Bühl, S. Alexander, S. Crewell, A. Heymsfield, H. Kalesse, A. Khain, M. Maahn, K. Van Tricht, and M. Wendisch

on a global scale with active remote sensing methods ( Zhang et al. 2010 ). Both satellites were put into the same orbit, one following the other with a distance of about a hundred kilometers or 17 s. They were embedded into NASA’s afternoon constellation (A-Train) of satellites. The new satellite Earth Clouds, Aerosols and Radiation Explorer (EarthCARE; Illingworth et al. 2015 ) of the European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) to be launched in 2018 will

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