Effect of insolation variations on vegetations of the Eurasian subarctic during the Holocene

Abstract

Variation of the insolation is one of the global factors which determine the Earth's climate. Multi-periodic variations of the insolation determine the cyclicity of the Earth's climate. The aim of the investigation is the estimation of the insolation variations influence on vegetations of the Urals and West Siberia subarctic during the Holocene. The calculation of insolation in the Eurasian Subarctic for the Holocene is carried out based on the solution La2004 for the long-period evolution of the Earth's orbit. We have estimated the insolation for the latitudes from 55° to 70° N. We have considered the mean daily and mean monthly insolation over 12 ka BP. We assess changes of the insolation in the Eurasian subarctic under the influence of such factor as the topography evolution. The surface topography was analyzed for the recent period (in the Urals and West Siberia) and the Pliocene epoch (in West Siberia). An assessment of the difference in the corresponding digital elevation models showed that the subsidence of the crust took place in West Siberia (the median value of the difference between the digital elevation models was 230.7 m above sea level). The intensity of erosion processes increased in a southerly direction. We have shown that an increase in the number of autumn's months with high insolation correlates with the taiga biome 4 thousand years ago to wider territories than 8 thousand years ago. © Published under licence by IOP Publishing Ltd.