Achim Drebs

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

Abstract 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°–70°N, 70°W–50°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...

Trends in Nordic and Arctic Temperature Extremes and Ranges

The national meteorological institutes in the Nordic countries have produced a comprehensive dataset of climatic extreme temperatures (monthly mean daily maximum and minimum, and monthly absolute highest and lowest temperatures) comprising stations from Fenno-Scandia, the Nordic Seas, and Greenland. Mean maximum and minimum temperatures show statistically significant negative trends in western coastal Greenland during the period 1950-95, while over the Nordic Seas and Fenno-Scandia the trends are generally positive. The diurnal temperature range (DTR) is decreasing significantly throughout the study area and is unrelated to regional temperature trends, which show both warming and cooling. The opposite temperature trends between western coastal Greenland and Fenno-Scandia since the 1950s are in accordance with a strengthening of the North Atlantic Oscillation (NAO). However, the simple NAO index fails to explain the decrease of DTR. In Fenno-Scandia, the reliable long-term mean maximum and minimum temperatures show cooling in winter and warming in spring and summer during the period 1910-95. Simultaneously, DTR has been decreasing in all seasons except winter. Most of the decrease has occurred since the 1940s. Atmospheric circulation indices defined by zonal and meridional sea level pressure differences, along with sea level pressure and cloud cover anomalies were used to build a multiple linear regression model for the Fenno-Scandian DTR. During the period 1910-95 the model explains from 53% (winter) to 80% (summer) of the variation in DTR and reproduces the statistically significant decreasing trend on annual level. Cloud cover is the dominant predictor, while circulation provides substantial improvement in explanation.

Hourly test reference weather data in the changing climate of Finland for building energy simulations

Dynamic building energy simulations need hourly weather data as input. The same high temporal resolution is required for assessments of future heating and cooling energy demand. The data presented in this article concern current typical values and estimated future changes in outdoor air temperature, wind speed, relative humidity and global, diffuse and normal solar radiation components. Simulated annual and seasonal delivered energy consumptions for heating of spaces, heating of ventilation supply air and cooling of spaces in the current and future climatic conditions are also presented for an example house, with district heating and a mechanical space cooling system. We provide details on how the synthetic future weather files were created and utilised as input data for dynamic building energy simulations by the IDA Indoor Climate and Energy program and also for calculations of heating and cooling degree-day sums. The information supplied here is related to the research article titled “Energy demand for the heating and cooling of residential houses in Finland in a changing climate” [1].