 |
| Titel |
An annually-resolved stalagmite tropical cyclone reconstruction from Belize reveals a northward shift in North Atlantic storm track position since 1550 C.E. |
| VerfasserIn |
Lisa Baldini, James Baldini, Jim McElwaine, Amy Frappier, Yemane Asmerom, Kam-biu Liu, Keith Prufer, Harriet Ridley, Victor Polyak, Douglas Kennett, Colin Macpherson, Valorie Aquino, Jaime Awe, Sebastian Breitenbach |
| Konferenz |
EGU General Assembly 2017
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250153950
|
| Publikation (Nr.) |
 EGU/EGU2017-18989.pdf |
|
|
|
|
|
| Zusammenfassung |
| Hurricanes are large-scale atmospheric phenomena that typically produce high volume, high
intensity, and isotopically depleted rainfall. Such storms have the ability to alter the isotopic
composition of the groundwater reservoir, imparting a uniquely negative isotopic fingerprint
to actively growing stalagmites. In regions influenced by the Intertropical Convergence Zone
(ITCZ), large volumes of rainfall delivered during the wet season can obscure the tropical
cyclone (TC) rainfall proxy signal. Coupled annually resolved carbon and oxygen isotope
ratios were used to isolate the low δ18O TC signal from the isotopically more enriched
background rainfall associated with seasonal ITCZ migration. The new composite
stalagmite proxy record yielded a 99.7% significant correlation with the western
Caribbean-filtered HURDAT2 database over the instrumental record based on a
non-parametric bootstrap approach. The new annually-resolved TC reconstruction for the
western Caribbean spans the last 450 years and reveals a peak in western Caribbean TCs at
1650 C.E. and a gradual decline until a marked decrease is observed at the start
of the Industrial Era. Comparison with documentary records of TC occurrence
along the US eastern seaboard reveals a clear pattern of north-eastward TC track
migration since peak Little Ice Age cooling. This pattern is consistent with natural
warming since the Little Ice Age temperature minimum and with anthropogenic
influences after industrialisation. Satellite observations reveal Hadley cell expansion has
occurred over the last three decades and modelling studies implicate rising atmospheric
greenhouse gas concentrations as the driver. Our results suggest that Hadley cell position
and width is a major control on hurricane track position and that future emissions
scenarios (continued rising greenhouse gases coupled with decreasing Northern
Hemisphere aerosol emissions) are likely to increase storm risk to the north-eastern USA. |
|
|
|
|
|
|