[1] We analyze century-long daily temperature and precipitation records for stations in Europe west of 60°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°E, show a warming for all temperature indices. Winter has, on average, warmed more ($1.0°C/100 yr) than summer ($0.8°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°C for 98th and 95th, but $1.0°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°N, have increased significantly by $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.

No abstract

This article addresses climatic fluctuations in the Czech Republic in the period . On the basis of data collected at 23 climatological stations, the fluctuations in monthly, seasonal, and annual series of selected climate variables, homogenized by means of Standard Normal Homogeneity Test (SNHT) (after Alexandersson), are analysed. With almost unchanging temperature continentality expressed by the Gorczyński index, the annual series of mean air temperature, maximum and minimum temperature, daily temperature range, and sunshine duration all exhibit a rising linear trend, in contrast to dropping trends in relative air humidity, number of days with snow cover, and mean wind speed. There are no pronounced changes in precipitation totals, although their distribution over the course of the year becomes more regular in terms of the Markham seasonality index. Temperature trends, with the exception of autumn, show a clear enhancement since the 1980s; statistically significant rising trends occur for only spring, summer and the year in a good agreement with the Northern Hemisphere series. Linkage to fluctuation in the North Atlantic Oscillation Index (NAOI) is best expressed by the Czech temperature characteristics for January, February, and winter (in similar fashion to that for the number of days with snow cover), which can be ascribed to intensification of the western airflow over Central Europe. On the other hand, linkage to NAOI for precipitation is essentially weaker, because of the role of synoptic processes in influencing the occurrence of precipitation at the regional scale. Better relationships for temperature variables and wind speed are obtained if the Central European Zonal Index (CEZI) is used instead of NAOI as an indicator of circulation patterns in Central Europe.

No abstract

No abstract