Climatic changes in the Urals over the past millennium. An analysis of geothermal and meteorological dataReportar como inadecuado

Climatic changes in the Urals over the past millennium. An analysis of geothermal and meteorological data - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

1 Institute of Geophysics UB RAS 2 Institute of Geology

Abstract : This investigation is based on a study of two paleoclimatic curves obtained in the Urals 51?59° N, 58?61° E: i a ground surface temperature history GSTH reconstruction since 800 AD and ii meteorological data for the last 170 years. Temperature anomalies measured in 49 boreholes were used for the GSTH reconstruction. It is shown that a traditional averaging of the histories leads to the lowest estimates of amplitude of past temperature fluctuations. The interval estimates method, accounting separately for the rock-s thermal diffusivity variations and the influence of a number of non-climatic causes, was used for obtaining the average GSTH. Joint analysis of GSTH and meteorological data bring us to the following conclusions. First, ground surface temperatures in the Medieval maximum during 1100?1200 was 0.38 K higher than the 20th century mean temperature 1900?1960. The Little Ice Age cooling was culminated in 1720 when surface mean temperature was 1.58 K below than the 20th century mean temperature. Secondly, contemporary warming began approximately one century prior to the first instrumental measurements in the Urals. The rate of warming was +0.25K-100years in the 18th century, +1.15 K-100years in the 19th and +0.75 K-100years in the first 80 years of the 20th. Finally, the mean rate of temperature warming increased in final decades of 20th century. An analysis of linear regression coefficients in running intervals of 11, 21 and 31 years, shows that there were periods of warming with almost the same rates in the past, including the 19th century.

Autor: D. Yu. Demezhko - I. V. Golovanova -



Documentos relacionados