Uwarunkowania cyrkulacyjne ilości całkowitego promieniowania słonecznego docierającego do powierzchni ziemi w Polsce w latach 1986–2015 = Atmospheric circulation determinants of the amount of global solar radiation reaching the land surface in Poland in the years 1986–2015

Abstract

Solar radiation is a key element of the Earth’s climate system and one of the most important variables in the energy balance of the active surface. The inflow of radiant energy to the Earth’s surface depends on the movement (circulation) of the atmosphere and on the associated changes in the amount of aerosols contained in the atmosphere as well as on cloudiness changes (which reduce the inflow of radiation to the Earth’s surface through reflection, dispersion and absorption processes). In that context, the work detailed in this paper had as its main aim a determination of the influence of atmospheric circulation on the amount of global solar radiation reaching the land surface in Poland. The research was based on source material from 1986–2015, originating from meteorological reanalyses and satellite products. Global solar radiation was analysed based on data from CM SAF satellite products, while atmospheric circulation types were designated with the use of modified version of the Lityński’s classification. Mean daily sums of radiation during individual circulation types, during A, 0, C macrotypes and on days with advection from particular directions were presented. Also the spatial distribution of radiation over the area of Poland during individual circulation types was shown. In the analyses special attention was paid to days with extremely large sums of solar radiation (above the 0.95 percentile). The largest daily sums of solar radiation are connected with anticyclonic circulation types, and the smallest ones – with cyclonic types. The largest mean daily sum of solar radiation occurs during south-western anticyclonic circulation, which is related to the significantly expanded Azores High. The smallest daily sums of solar radiation occur during cyclonic types, with advection of air masses from the north and east – in spring during NWC type, in autumn during EC type, in summer and winter during NEC type. The spatial distribution of solar radiation daily sums over the territory of Poland also depends on the circulation type. For most of the year, the circulation types with the northern and eastern components (N-NE-E) are associated with the reduction of the amount of solar radiation from north to south, while the inflow of air masses from the S-SW-W directions favours the reduction of radiation from south to north. Extremely large sums of solar radiation occur most probably during anticyclonic types with advection of air masses from SW, S and SE, and during the advectionless circulation 0A (conditional probability 0.13, 0.13, 0.11 and 0.10 respectively). The paper also demonstrates that the circulation type (i.e. prevailing pressure system) has a greater influence on daily sums of global solar radiation over Poland than the direction of air masses advection. The research results show that atmospheric circulation plays a significant role in determining the amount of solar radiation reaching the land surface in Poland.