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| Titel |
Surface thermal perturbations of the recent past at low latitudes – inferences based on borehole temperature data from Eastern Brazil |
| VerfasserIn |
V. M. Hamza, A. S. B. Cavalcanti, L. C. C. Benyosef |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 3, no. 3 ; Nr. 3, no. 3 (2007-08-28), S.513-526 |
| Datensatznummer |
250001078
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| Publikation (Nr.) |
 copernicus.org/cp-3-513-2007.pdf |
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| Zusammenfassung |
| Borehole temperature data from the eastern parts of Brazil has been examined
in an attempt to extract information on surface thermal perturbations of the
recent past at low latitudes. Forward models were employed in the
analysis of temperature logs from 17 localities and, in addition, Bayesian
inverse modeling was carried out for data from 14 selected sites. The model
results have allowed determination of the magnitude as well as the duration
of ground surface temperature (GST) changes in three major geographic zones
of Brazil. Prominent among such changes are the warming episodes that
occurred over much of the subtropical highland regions in the southeastern
parts of Brazil. The present magnitude of GST changes in this region are in
the range of 2 to 3.5°C but have had their beginning during the early
decades of the 20th century. Nearly similar trends are also seen in
temperature-depth profiles of bore holes in the subtropical humid zones of
the interior and coastal areas of southern Brazil. The data from semi arid
zones of northeast Brazil also indicate occurrence of surface warming events
but the magnitudes are in the range of 1.4 to 2.2°C while the duration
of the warming event is larger, extending back into the last decades of the
19th century. There are indications that changes in both climate and
vegetation cover contribute to variations in GST. Thus the magnitudes of GST
variations are relatively large in localities which have undergone changes
in vegetation cover. Also there are indications that GST changes are
practically insignificant in areas of tropical rain forest. Another
important result emerging from model studies is that the climate was
relatively cooler during the 17th and 18th centuries. The climate
histories, deduced from geothermal data, are found to be consistent with
results of available meteorological records in southern Brazil. Comparative
studies also indicate that the magnitudes and duration of recent climate
changes in southern and eastern Brazil are similar to those found in other
continental areas such as North America, Asia and Europe. |
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