The Network of European World Meteorological Deutscher Meteorological Services Organization Wetterdienst European Climate Support World Climate Data Department Climate Network and Monitoring Programme Monitoring Annual Bulletin on the Climate in WMO Region VI - Europe and Middle East - 2010 ISSN: 1438 – 7522 Internet version: http://www.dwd.de/rcc-cm Editor: Deutscher Wetterdienst P.O. Box 10 04 65, D – 63004 Offenbach am Main, Germany Phone: +49 69 8062 2936 Fax: +49 69 8062 3759 Responsible: Peter Bissolli E-mail: [email protected] Technical assistance: Volker Zins E-mail: [email protected] Acknowledgements: Special thanks go to our colleagues G. Engel, K. Friedrich, G. Müller-Wester- meier and B. Tinz from DWD and M. Kendon from UK Met Office for their valu- able comments and corrections, as well as to our special guest authors A. v. Engelen (ECSN), W. Steinbrecht, H. Claude and U. Köhler (DWD). This bulletin is an extended version of the publication: F. Maier et al., 2011: Regional Climates - Europe, in “State of the climate in 2010”. Bull. Amer. Meteor. Soc., 92 (6), pp. 199-210. The text was compiled on the basis of the monthly bulletins on the climate in WMO Region VI provided by DWD (see URL above), various other climate re- views available at WMO and DWD, additional web information and other con- tributions kindly provided by the RA VI Members. This Bulletin is a product of the WMO RA VI Pilot Regional Climate Centre, Node on Climate Monitoring (RCC-CM). Annual Bulletin on the Climate in WMO Region VI - Europe and Middle East - 2010 The Bulletin is a summary of contributions from the following National Meteorological and Hydrological Services and was co-ordinated by the Deutscher Wetterdienst, Germany Armenia Austria Azerbaijan Belgium Bosnia and Herzegovina Bulgaria Croatia Cyprus Czech Republic Denmark Estonia Finland France Georgia Germany Greece Hungary Iceland Ireland Israel Italy Jordan Kazakhstan Latvia Lithuania Luxembourg Malta Moldova Montenegro Netherlands Norway Poland Portugal Romania Russia Serbia Slovakia Slovenia Spain Sweden Switzerland Turkey Ukraine United Kingdom List of Contents Foreword 5 Outstanding Events and Anomalies 6 Annual Survey 7 Seasonal Survey 43 Seasonal Maps 55 Monthly and Annual Tables 59 Monthly Surveys January 66 February 73 March 79 April 84 May 87 June 92 July 98 August 104 September 112 October 116 November 120 December 127 SPECIAL CONTRIBUTIONS: ECSN Activities Report 2010 135 The Ozone Layer over Central Europe in 2010 139 Sources 141 Annual Bulletin on the Climate in WMO Region VI - 2010 5 Foreword Climate was again a hot topic in 2010, also in RA VI. This time, it was not only the global warming, but also the extreme winter cold spells which attracted much attention from the public. In fact, large parts of Europe experienced a cold and snowy winter 2009/10 and once more an outstandingly cold and snowy December 2010. On the other hand, an extremely long and intense heat wave affected particularly the European part of Russia and neighbouring countries in summer, and mild weather in the Arctic region caused again a very low sea ice extent. It has become clear that the extremely negative values of the Arctic Oscillation were a main contributor to annual climate variability. In this context, the year 2010 showed very clearly that even in a time of global warming, extreme warm and cold periods can still occur repeatedly, which has to be considered when talking about adaptation strategies. In terms of precipitation, some areas were equally affected by repeated extremes, such as flooding in eastern central Europe in May and in August and September. As for storms, we still have not forgotten the storm Xynthia crossing France and Germany in late February 2010. All these examples show that a good co-operation of the national meteorological and hydrological services of our Region in climate issues is essential for monitoring and, as far as possible, forecasting regional climate variability. The development of a Regional Climate Centre (RCC) Network in RA VI is the right step in this direction. I was very pleased to attend the “WMO Workshop on Climate Monitoring including the implementation of climate watch systems in RA VI”, which was jointly organised by the WMO and the Deutscher Wetterdienst (DWD) in Germany in 2010, and where representatives of the members of the RCC-Network and of the National Meteorological and Hydrological Services as well as other interested participants came together. The Network is now in its pilot phase, with the designation procedure in progress. The Annual Bulletin on the Climate in RA VI, which is on its 17th issue this year, continues to be an important backbone within the RCC product suite. Considering the requests of some of our Members to extend our assessments beyond the area of our Region, a global overview of temperature and precipitation anomalies has been added. As in previous years, the Annual Bulletin also presents an extensive summary of all important climate events of 2010 in our Region, compiled from the excellent material provided by many of our Members. Once again, it is a pleasure for me to thank all the Members for their contributions. My special thanks go to the editorial team of DWD, namely Dr Peter Bissolli, for compiling and writing all the texts and Volker Zins for his technical support as well as to all reviewers. I wish you a pleasant reading and hope this Bulletin will be helpful for your work in climatology. Ivan Cacic President of WMO Regional Association VI 6 Annual Bulletin on the Climate in WMO Region VI - 2010 Outstanding Events and Anomalies in 2010 Temperature - Long and intense heat wave in July and August in European Russia and adjacent areas - Cold winter 2009/10 and cold December 2010 in large parts of Europe Precipitation - Several flooding events in eastern central Europe (May, August, September) - Long summer drought periods in central European Russia and in the Middle East - Extensive snow cover in large parts of Europe in winter 2009/10 and in December 2010 Storm - Heavy storm (Xynthia) over south-western, western and central Europe at the end of February 2010 Annual Bulletin on the Climate in WMO Region VI - 2010 7 Annual Survey 1. Atmospheric circulation The main features of the global atmospheric circulation in 2010 were a transition from El Niño to a very strong La Niña and a strongly negative Arctic Oscillation and North Atlantic Oscillation in particular during the cold season in RA VI, associated with the domination of meridional patterns over Europe. 1.1. El Niño / La Niña 2010 started with El Niño conditions stronger than those at the end of 2009. They were most distinct in February and then weakened rapidly in early spring (Fig. 0.1). A typical feature of El Niño is the stronger subtropical jet and a dislocation of the Icelandic low to a far more southerly position, which was very pronounced in February. As a consequence, wet conditions prevailed over Iberia and the Mediterranean in the winter 2009/10, whereas it was cold and dry particularly in northern Europe. In April 2010, the Southern Oscillation index entered into a La Niña phase, which became gradually stronger during the course of the year. Full La Niña conditions had arrived in August 2010. The highest value was achieved in December with 2.9 (standardised), which is also the highest value ever reached in at least 60 years (according to data from NOAA) and was assessed as one of the five strongest La Niña events since the beginning of the 20th century. Nevertheless, the impact on the surface pressure field over the North Atlantic and Europe was masked by a strong negative North Atlantic Oscillation and Arctic Oscillation. Fig. 0.1: Standardised Southern Oscillation index for 2010, as expressed by the difference of stan- dardised sea level pressure anomalies in Tahiti and Darwin (Australia) Source: NOAA, www.cpc.ncep.noaa.gov/data/indices/soi, 8 February 2012 8 Annual Bulletin on the Climate in WMO Region VI - 2010 1.2. Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) The Arctic Oscillation index (Fig. 0.2) was highly negative during the winter months January and February 2010 and once again at the beginning of the next winter in December 2010. This implies that a mainly meridional circulation pattern prevailed in the northern hemisphere during all winter months. As a consequence, there was a strong meridional exchange of Arctic air masses and milder air masses from more southern latitudes. Thus, most of Europe saw colder winter months than normal, whereas the Arctic was relatively mild. During the rest of the year, the AO index was close to zero, implying only weak impact. Averaged over the whole year 2010, however, the pressure gradient between middle and high latitudes of the northern hemisphere decreased compared to 2009. The NAO index was negative during almost the whole year, except July when the index was close to zero. This implied the existence of a stronger-than-normal meridional circulation component over the North Atlantic; westerly airflows from the Atlantic to Europe were quite rare. Annual mean air pressure was up to 10 hPa higher in Greenland and the Icelandic low was dislocated towards Newfoundland while the Azores high was weaker than normal. Sea level pressure in Iceland reached its highest annual average on record since 1823 (1014 hPa). Like the AO, the NAO too had an extremely negative phase in the winter months, when the impact of the NAO on Europe is very strong. Iceland was often dominated by high pressure whereas low pressure prevailed over the Azores, which is the quite the reverse of normal conditions.