Historiska observationer av temperatur, vegetationsperiodens längd, nederbörd, snö, globalstrålning och geostrofisk vind i Sverige har analyserats. Längden på de tillgängliga tidsserierna varierar mellan de olika variablerna. Det finns dagliga temperaturobservationer från Uppsala så långt tillbaka som 1722, medan startåret för de globalstrålningsmätningar från åtta svenska stationer som analyserats här är så sent som 1983. Klimatindikatorer som baseras på dessa observationer visar att:• Sveriges årsmedeltemperatur har ökat med 1,9 °C jämfört med perioden 1861–1890. • Sveriges årsnederbörd har ökat sedan 1930 från 600 mm/år till nästan 700 mm/år. • Antalet dagar med snötäcke har minskat sedan 1950. • Globalstrålningen har ökat med cirka 10 % sedan mitten av 1980-talet. • Någon förändring av den geostrofiska vinden kan inte fastslås från 1940.De ovan listade förändringarna syftar alla till årliga genomsnitt för hela Sverige. De är statistiskt signifikanta i de flesta fall. Bilden blir mer tvetydig då genomsnitt för olika landsdelar eller säsonger undersöks. Exempelvis är den ökade årsnederbörden mest ett resultat av ökad nederbörd under vinter och höst, medan det inte finns någon tydlig trend för sommar och vår. Det är också generellt sett svårare att fastslå förändringar i extremvärden. Exempelvis finns ingen signifikant trend vad gäller vinterns största snödjup, trots en tydlig minskning i antalet dagar med snötäcke.

Historical Swedish observations of temperature, length of vegetation period, precipitation, snow, global radiation, and geostrophic wind have been analysed. The length of available time series varies among these variables. Whereas there are temperature observations for Uppsala ranging back to 1722 continuous measurements of global radiation at eight Swedish stations start only in 1983. Climate indicators based on these observations show that: • The annual mean temperature for Sweden has increased by 1.9 °C compared to the period 1861• The amount of annual precipitation increased since 1930 from about 600 mm/year to almost 700 mm/year. • The number of days with snow cover has reduced since 1950. • The global radiation increased with circa 10 % since the mid-1980’s. • The geostrophic wind has no clear change pattern since 1940. The listed changes are annual averages for Sweden. These are robust and statistically significant in most cases. The picture is getting more diverse when investigating smaller regions or different seasons instead of annual means. For instance, the increase of precipitation is mainly related to enhanced precipitation during autumn and winter whereas there are no obvious trends in spring and summer. Moreover, changes in extremes are generally harder to identify. For instance, despite the clear negative trend in the number of days with snow cover there is no significant trend for the maximum snow depth. –1890.Denna

Accurate determination of the amount of incoming solar radiation at Earth's surface is important for both climate studies and solar power applications. Satellite-based datasets of solar radiation offer wide spatial and temporal coverage, but careful validation of their quality is a necessary prerequisite for reliable utilization. Here we study the retrieval quality of one polar-orbiting satellite-based dataset (CLARA-A1) and one geostationary satellite-based dataset (SARAH), using in situ observations of solar radiation from the Finnish and Swedish meteorological measurement networks as reference. Our focus is on determining dataset quality over high latitudes as well as evaluating daily mean retrievals, both of which are aspects that have drawn little focus in previous studies. We find that both datasets are generally capable of retrieving the levels and seasonal cycles of solar radiation in Finland and Sweden well, with some limitations. SARAH exhibits a slight negative bias and increased retrieval uncertainty near the coverage edge, but in turn offers better precision (less scatter) in the daily mean retrievals owing to the high sampling rate of geostationary imaging.