Geothermal paleoclimate observatory in Eastern Europe |
|
|
Wednesday, 23 November 2011 | by
This e-mail address is being protected from spambots. You need JavaScript enabled to view it
| Hits : 2910 |
|
Abstract of the lecture.
Reconstruction of the past climate changes by inversion of the present-day subsurface temperature-depth profiles measured in deep boreholes has established as one of the proxy methods in paleoclimate research in the last two decades.
The temperature-depth profiles obtained by precise temperature logging in boreholes several hundred metres to 2 - 3 km deep can be used to reconstruct the ground surface temperature history on the time scale of several past centuries up to the last glacial/Holocene transition, respectively.
Heat conduction, considered in the reconstruction technique as the only mechanism of
the heat transport in rocks, is definitely not the only heat transfer mechanism in soil. The reconstructed ground surface temperature histories are therefore temporal changes of the ground temperature at the upper boundary of the heat conduction domain, which begins somewhere in the soil - bedrock transition zone. The long-term relationship between the soil and surface air temperatures is therefore the key issue in interpreting the results in terms of the long-term climatic variability. Meteorological factors like precipitation, cloudiness, wind, soil moisture, thickness and duration of the snow cover and environmental factors like a type of a vegetation cover are suspected to influence appreciably the air-soil temperature difference.
In order to explore this relationship, the long-term monitoring of the air-ground temperature coupling has been launched at the campus of the Institute of Geophysics in Prague (50_ 02’ 27" N, 14_ 28’ 39" E, 274 m a.s.l.) in 1993. The air- soil-bedrock temperature observations were complemented by the soil temperature monitoring under different types of surface (grass, sand, bare soil, asphalt) at the depths of 2, 5, 10, 20 and 50 cm, as well as by air temperatures at 5 cm above each of the surface types and at 2 m above the background grass surface in 2003.
The results of this eight year monitoring indicate that the annual mean of the soil – air temperature difference depends strongly on the type of the surface – grass, sand, bare soil, asphalt – and amounts up to 4 – 5 °C. The inter-annual variations of the difference for the given surface are smaller, typically about 1 °C. This variance is of the same order as the amplitude of the long-term observed and/or estimated surface temperature changes. However, the observational period of eight years is too short to detect any statistically relevant trend and to prove or falsify the assumption that on the decadal scale the annual mean of the difference is constant.
Jan Safanda, Institute of Geophysics Prague, Czech Academy of Sciences
Local : CLAV, Anfiteatro 1 - 23 de Novembro 2011 - 14:30h
Error: Your php install does not support GD.
This is a requirement for FBoxBot |
Location :
Error: Your php install does not support GD.
This is a requirement for FBoxBot Contact :
Error: Your php install does not support GD.
This is a requirement for FBoxBot |
Error: Your php install does not support GD.
This is a requirement for FBoxBot |
Back
JEvents v1.5.4
Copyright © 2006-2010
|