putation of the photolysis rates, a scheme was adopted that accurately describes photolysis at large solar zenith angles

In 2011, the German Federal Ministry of Transport, Building and Urban Development laid the foundation of the Hans-Ertel Centre for Weather Research [Hans-Ertel-Zentrum für Wetterforschung (HErZ)] in order to better connect fundamental meteorological research and teaching at German universities and atmospheric research centers with the needs of the German national weather service Deutscher Wetterdienst (DWD). The concept for HErZ was developed by DWD and its scientific advisory board with input from the entire German meteorological community. It foresees core research funding of about €2,000,000 yr−1 over a 12-yr period, during which time permanent research groups must be established and DWD subjects strengthened in the university curriculum. Five priority research areas were identified: atmospheric dynamics and predictability, data assimilation, model development, climate monitoring and diagnostics, and the optimal use of information from weather forecasting and climate monitoring for the benefit of society. Following an open call, five groups were selected for funding for the first 4-yr phase by an international review panel. A dual project leadership with one leader employed by the academic institute and the other by DWD ensures that research and teaching in HErZ is attuned to DWD needs and priorities, fosters a close collaboration with DWD, and facilitates the transfer of fundamental research into operations. In this article, we describe the rationale behind HErZ and the road to its establishment, present some scientific highlights from the initial five research groups, and discuss the merits and future development of this new concept to better link academic research with the needs and challenges of a national weather service.

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During the EASOE campaign measurements have been performed in March at Ny‐Ålesund (79°N, 11°E) by high resolution FTIR spectroscopy to derive the vertical column amounts of ClONO2. For the first part of this period the polar vortex was found to be situated above Ny‐Ålesund. The measurements give ClONO2 zenith column amounts of about 3.9×1015 mol cm−2 outside the polar vortex, much higher than midlatitude values for an undisturbed atmosphere. Inside the vortex strong variabilities with burdens between 2.8 and 6.8×1015 mol cm−2 were observed. These high values might be explained by the reaction of ClO with NO2 and the relatively warm stratosphere ensuring that the ClONO2 so formed remains in the gas phase.

IntroductionThe meteorological conditions in hilly terrain are characterized by the formation of secondary circulation systems, which exhibit typical periodic daily variations [Atkinson, 1981]. In addition, a mixing layer develops over hilly terrain, which is subject to strong time and spatial variations over the day [de Wekker, 1995

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Zenith column amounts of N2O, CH4, CFC‐12, O3, HNO3, ClONO2, HCl, and HF were measured by ground‐based FTIR spectrometers at Kiruna in November 1991 and from January to March 1992, and in January and March 1992 in Sondre Stromfjord, Greenland. They were correlated to the dynamical situation of the stratosphere and interpreted in terms of chemical processes, with respect to the position of the vortex, the stratospheric temperatures, and the trajectories of the air masses for the last ten days. One of the most remarkable results is the increasing ClONO2 burden from the end of January to mid‐March, reaching the extremely high value of 7.2 × 1015 molec./cm².