Reijo Hyvönen

Calculations on the wind climate in northern Finland: the importance of inversions and roughness variations during the seasons

The wind power potential around Pyhatunturi Fell in northern Finland is calculated with WAsP and the Karlsruhe Atmospheric Mesoscale Model (KAMM) using a climatology of the geostrophic wind from the global reanalysis of NCEP/NCAR. The importance of roughness variations between summer and winter due to snow cover and of strong, low-level inversions during winter is investigated. At the position of a telemast on the fell the changing roughness led to an increase in the predicted wind power density of only 1% at 61 m. However, frequent inversions in winter have a major influence on the wind potential on the fell areas. Accounting for them increased the predicted wind power density by 10%–16%, giving better agreement with the observations. As expected, the wind in the plains is reduced during conditions with inversions. The simulations with KAMM were performed for a grid map with a resolution of 350 m. This is too rough to resolve the steep slopes of Pyhatunturi Fell. Therefore the predicted wind speed on the summit is underestimated by up to 15% depending on the wind direction. Copyright

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].

Precipitation and evaporation budgets over the Baltic Proper : Observations and modelling

Precipitation and evaporation budgets over the Baltic Sea were studied in a concerted project called PEP in BALTEX (Pilot study of Evaporation and Precipitation in the Baltic Sea), combining extensive field measurements and modelling efforts. Eddy-correlation-measurements of turbulent heat flux were made on a semi-continuous basis for a 12 month period at four well-exposed coastal sites in the Baltic Proper (the main basin of the Baltic Sea). Precipitation was measured at land-based sites with standard gauges and on four merchant ships travelling between Germany and Finland with the aid of specially designed ship rain gauges (SRGs). The evaporation and precipitation regime of the Baltic Sea was modelled for a 12 month period by applying a wide range of numerical models: the operational atmospheric High Resolution Limited Area Model (HIRLAM, Swedish and Finnish versions), the German atmospheric REgional-scale MOdel, REMO, the operational German Europe Model (only precipitation), the oceanographic model PRO...