Daily mean sea level pressure reconstructions for the European-North Atlantic region for the period 1850-2003.

The development of a daily historical European-North Atlantic mean sea level pressure dataset (EMSLP) for 1850-2003 on a 5 latitude by longitude grid is described. This product was produced using 86 continental and island stations distributed over the region 25 degrees-70 degrees N, 70 degrees W-50 degrees E blended with marine data from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS). The EMSLP fields for 1850-80 are based purely on the land station data and ship observations. From 1881, the blended land and marine fields are combined with already available daily Northern Hemisphere fields. Complete coverage is obtained by employing reduced space optimal interpolation. Squared correlations (r(2)) indicate that EMSLP generally captures 80%-90% of daily variability represented in an existing historical mean sea level pressure product and over 90% in modern 40-yr European Centre for Medium-Range Weather Forecasts Re-Analyses (ERA-40) over most of the region. A lack of sufficient observations over Greenland and the Middle East, however, has resulted in poorer reconstructions there. Error estimates, produced as part of the reconstruction technique, flag these as regions of low confidence. It is shown that the EMSLP daily fields and associated error estimates provide a unique opportunity to examine the circulation patterns associated with extreme events across the European-North Atlantic region, such as the 2003 heat wave, in the context of historical events

Indices for daily temperature and precipitation extremes in Europe analyzed for the period 1901-2000

We analyze century-long daily temperature and precipitation records for stations in Europe west of 60 degrees E. A set of climatic indices derived from the daily series, mainly focusing on extremes, is defined. Linear trends in these indices are assessed over the period 1901-2000. Average trends, for 75 stations mostly representing Europe west of 20 degrees E, show a warming for all temperature indices. Winter has, on average, warmed more (similar to 1.0 degrees C/100 yr) than summer (similar to 0.8 degrees C), both for daily maximum (TX) and minimum (TN) temperatures. Overall, the warming of TX in winter was stronger in the warm tail than in the cold tail (1.6 and 1.5 degrees C for 98th and 95th, but similar to 1.0 degrees C for 2nd, 5th and 10th percentiles). There are, however, large regional differences in temperature trend patterns. For summer, there is a tendency for stronger warming, both for TX and TN, in the warm than in the cold tail only in parts of central Europe. Winter precipitation totals, averaged over 121 European stations north of 40 degrees N, have increased significantly by similar to 12% per 100 years. Trends in 90th, 95th and 98th percentiles of daily winter precipitation have been similar. No overall long-term trend occurred in summer precipitation totals, but there is an overall weak (statistically insignificant and regionally dependent) tendency for summer precipitation to have become slightly more intense but less common. Data inhomogeneities and relative sparseness of station density in many parts of Europe preclude more robust conclusions. It is of importance that new methods are developed for homogenizing daily data