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Martin Weissmann, Florian Harnisch, Chun-Chieh Wu, Po-Hsiung Lin, Yoichiro Ohta, Koji Yamashita, Yeon-Hee Kim, Eun-Hee Jeon, Tetsuo Nakazawa, and Sim Aberson

operational Korea Meteorological Administration (KMA) Global Data Assimilation and Prediction System (GDAPS) forecast data (0000 and 1200 UTC) from 1 to 30 September 2008. The WRF model was used for forecasts up to a lead time of 72 h. The horizontal resolution was 30 km (190 × 190 grid points) and the GDAPS (T426L40) global model data were used for initial and boundary conditions. The physics packages included the WSM6 microphysics scheme, the Kain–Fritsch cumulus parameterization scheme, the Noah land

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Hilke S. Lentink, Christian M. Grams, Michael Riemer, and Sarah C. Jones

3). So, when ET takes place over the ocean, the structure of the storm is changing from an almost axisymmetric warm-core cyclone into a frontal cold-core cyclone with extratropical characteristics such as a broadening low-level wind field. Although ET is most common over the ocean ( Evans et al. 2017 ), the transition can take place near land and orography, like Japan, New Zealand, or the U.S. East Coast. When recurving TCs are close to a coastal mountainous area, enhanced precipitation is often

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Florian Harnisch and Martin Weissmann

. 2005 ). Several studies showed that despite the increased use of satellite data in the analysis of numerical weather prediction models, additional dropsonde measurements of key variables such as wind, temperature, and humidity in the environment of TCs can lead to improvements of TC track forecasts of the order of 10%–20% ( Aberson 2003 ; Wu et al. 2007b ; Yamaguchi et al. 2009 ). Despite the average reduction of track forecast errors, single cases occur where additional observations do not

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Gabriel Wolf and Volkmar Wirth

1. Introduction The statistics of midlatitude weather systems show significant deviations from zonal symmetry, especially in the Northern Hemisphere. This zonal asymmetry is at least partly caused by the uneven distribution of continental-scale orography and land–sea distribution (e.g., Swanson 2007 ). Close to the surface the asymmetry is associated with a zonal variation of storm tracks ( Hoskins and Valdes 1990 ; Chang and Orlanski 1993 ). In the upper troposphere it leads to a zonal

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Kirstin Kober and George C. Craig

of moisture and temperature in the atmosphere determines the amount of CAPE and is influenced by several processes, especially in the atmospheric boundary layer. Soil type, land use, orography, and elevation are important because they define properties of the interaction between the land surface and the atmosphere. Several processes contribute to create variability in a convective boundary layer. The heating of surfaces with different heat conduction properties by the sun causes turbulent eddies

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Lisa-Ann Quandt, Julia H. Keller, Olivia Martius, and Sarah C. Jones

supported the formation of the block ( Hong et al. 2011 ; Lau and Kim 2012 ; Schneidereit et al. 2012 ; Trenberth and Fasullo 2012 ). Fig . 1. Timeline providing an overview of the atmospheric blocking event over the European–Russian sector, the heat wave in Russia ( Barriopedro et al. 2011 ), and the extreme precipitation events in Pakistan ( Lau and Kim 2012 ) during summer 2010, as well as the 10-day forecasts used in this study. Two high-impact weather events were associated with this blocking

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Andreas Schäfler, Andreas Dörnbrack, Christoph Kiemle, Stephan Rahm, and Martin Wirth

) water vapor measurements in the tropics and subtropics over the Atlantic Ocean between Europe and Brazil. A mass flux (kg s −1 ) was calculated by Weissmann et al. (2005a) in a shallow stream toward the Alps using Doppler wind lidar (DWL) measurements. The first collocated lidar measurements of wind and water vapor were carried out during the International H 2 O Project (IHOP_2002) with a two-wavelength DIAL and a nonscanning DWL. Kiemle et al. (2007) used these observations to calculate

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Jana Čampa and Heini Wernli

present regions of enhanced cyclone track density and regions of cyclone genesis or lysis (e.g., Whitaker and Horn 1984 ; Hoskins and Hodges 2002 ; Wernli and Schwierz 2006 ). Although using different methods of cyclone identification and tracking, they all found some pronounced features such as the Atlantic and the Pacific storm tracks and a secondary maximum of cyclone frequency over the Gulf of Genoa. Several climatologies also consider other cyclone characteristics such as cyclone size

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Andrea Schneidereit, Silke Schubert, Pavel Vargin, Frank Lunkeit, Xiuhua Zhu, Dieter H. W. Peters, and Klaus Fraedrich

, transients, and large-scale modes may contribute to the long-lasting blocking high on different time scales. Therefore, the present study focuses on the analysis of the interannual time scale using the summer mean to indicate the quasi-stationary wave structure, the synoptic time scale analyzing the mean eddy influence, and the intermediate time scale (~10–60 days) to show the wave train evolution. Besides the atmospheric dynamics, the land surface–atmosphere feedback is an additional factor that could

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Maxi Boettcher and Heini Wernli

of occurrence and intensification of DRWs. The geographical distribution and scenarios of DRW generation are investigated in section 4 . Eventually section 5 focuses in particular on the explosively intensifying systems. Finally, the results are summarized and discussed in section 6 . 2. Data and DRW tracking The data used in this climatological study are operational analyses from the ECMWF for the years 2001–10, interpolated on a 0.6° horizontal grid and available every 6 h. In the vertical

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