Sunshine duration and its variability in the main ridge of the Karkonosze Mountains in relation to with atmospheric circulation

摘要: Sunshine duration analysis was based on a series of measurements spanning the period from 1901 to 2014 for Śniezka (1603 m a.s.l.) and 1961 2000 Szrenica (1362 m a.s.l.). The average annual sunshine (SD) is 1423.0 h, which among lowest values in Poland. On average, main ridge Karkonosze range receives 31% potential terms: 25% December 36% August May. changes recorded point existence two cycles: short one approx. 2–4 years long 60 years. former most probably reflects rhythm atmospheric circulation North Atlantic (North Oscillation), while latter impact ocean associated with AMO (Atlantic Multidecadal Oscillation) mechanism. Annual SD totals years 1901–2014 exhibit slight trend an increase 2.5 h/10 years, rate during winter quarter many times higher than other seasons. Average monthly differences between are positive all months year difference being 10 11 h. This means that radiation conditions more favourable range, lies at altitude 200 250 m lower. daily durations only shorter those macro-types advection south.