Ghent University Academic Bibliography

Advanced

Half-precessional dynamics of monsoon rainfall near the East African Equator

Dirk Verschuren UGent, Jaap S Sinninghe Damsté, Jasper Moernaut UGent, Iris Kristen, Maarten Blaauw, Maureen Fagot UGent, Gerald H Haug, the CHALLACEA project members, Marc De Batist UGent and Hilde Eggermont UGent (2009) NATURE. 462(7273). p.637-641
abstract
External climate forcings—such as long-term changes in solar insolation—generate different climate responses in tropical and high latitude regions. Documenting the spatial and temporal variability of past climates is therefore critical for understanding how such forcings are translated into regional climate variability. In contrast to the data-rich middle and high latitudes, high-quality climate-proxy records from equatorial regions are relatively few, especially from regions experiencing the bimodal seasonal rainfall distribution associated with twice-annual passage of the Intertropical Convergence Zone. Here we present a continuous and well-resolved climate-proxy record of hydrological variability during the past 25,000 years from equatorial East Africa.Our results, based on complementary evidence from seismic-reflection stratigraphy and organic biomarker molecules in the sediment record of Lake Challa near Mount Kilimanjaro, reveal that monsoon rainfall in this region varied at half-precessional (~11,500-year) intervals in phase with orbitally controlled insolation forcing. The southeasterly and northeasterly monsoons that advect moisture from the western Indian Ocean were strengthened in alternation when the inter-hemispheric insolation gradient was at a maximum; dry conditions prevailed when neither monsoon was intensified and modest local March or September insolation weakened the rain season that followed. On sub-millennial timescales, the temporal pattern of hydrological change on the East African Equator bears clear high-northern-latitude signatures, but on the orbital timescale it mainly responded to low-latitude insolation forcing. Predominance of low-latitude climate processes in this monsoon region can be attributed to the low-latitude position of its continental regions of surface air flow convergence, and its relative isolation from the Atlantic Ocean, where prominent meridional overturning circulation more tightly couples low-latitude climate regimes to high-latitude boundary conditions.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
COLLAPSE, INSOLATION, HOLOCENE, CLIMATE, MILLENNIAL-SCALE, ATLANTIC THERMOHALINE CIRCULATION, LAST GLACIAL MAXIMUM, TANZANIA, RECORD, BP
journal title
NATURE
Nature
volume
462
issue
7273
pages
637 - 641
Web of Science type
Article
Web of Science id
000272277900038
JCR category
MULTIDISCIPLINARY SCIENCES
JCR impact factor
34.48 (2009)
JCR rank
1/48 (2009)
JCR quartile
1 (2009)
ISSN
0028-0836
DOI
10.1038/nature08520
language
English
UGent publication?
yes
classification
A1
copyright statement
I have transferred the copyright for this publication to the publisher
id
854368
handle
http://hdl.handle.net/1854/LU-854368
date created
2010-02-06 19:02:09
date last changed
2013-07-03 13:23:52
@article{854368,
  abstract     = {External climate forcings---such as long-term changes in solar insolation---generate different climate responses in tropical and high latitude regions. Documenting the spatial and temporal variability of past climates is therefore critical for understanding how such forcings are translated into regional climate variability. In contrast to the data-rich middle and high latitudes, high-quality climate-proxy records from equatorial regions are relatively few, especially from regions experiencing the bimodal seasonal rainfall distribution associated with twice-annual passage of the Intertropical Convergence Zone. Here we present a continuous and well-resolved climate-proxy record of hydrological variability during the past 25,000 years from equatorial East Africa.Our results, based on complementary evidence from seismic-reflection stratigraphy and organic biomarker molecules in the sediment record of Lake Challa near Mount Kilimanjaro, reveal that monsoon rainfall in this region varied at half-precessional ({\texttildelow}11,500-year) intervals in phase with orbitally controlled insolation forcing. The southeasterly and northeasterly monsoons that advect moisture from the western Indian Ocean were strengthened in alternation when the inter-hemispheric insolation gradient was at a maximum; dry conditions prevailed when neither monsoon was intensified and modest local March or September insolation weakened the rain season that followed. On sub-millennial timescales, the temporal pattern of hydrological change on the East African Equator bears clear high-northern-latitude signatures, but on the orbital timescale it mainly responded to low-latitude insolation forcing. Predominance of low-latitude climate processes in this monsoon region can be attributed to the low-latitude position of its continental regions of surface air flow convergence, and its relative isolation from the Atlantic Ocean, where prominent meridional overturning circulation more tightly couples low-latitude climate regimes to high-latitude boundary conditions.},
  author       = {Verschuren, Dirk and Damst{\'e}, Jaap S Sinninghe and Moernaut, Jasper and Kristen, Iris and Blaauw, Maarten and Fagot, Maureen and Haug, Gerald H and CHALLACEA project members, the and De Batist, Marc and Eggermont, Hilde},
  issn         = {0028-0836},
  journal      = {NATURE},
  keyword      = {COLLAPSE,INSOLATION,HOLOCENE,CLIMATE,MILLENNIAL-SCALE,ATLANTIC THERMOHALINE CIRCULATION,LAST GLACIAL MAXIMUM,TANZANIA,RECORD,BP},
  language     = {eng},
  number       = {7273},
  pages        = {637--641},
  title        = {Half-precessional dynamics of monsoon rainfall near the East African Equator},
  url          = {http://dx.doi.org/10.1038/nature08520},
  volume       = {462},
  year         = {2009},
}

Chicago
Verschuren, Dirk, Jaap S Sinninghe Damsté, Jasper Moernaut, Iris Kristen, Maarten Blaauw, Maureen Fagot, Gerald H Haug, the CHALLACEA project members, Marc De Batist, and Hilde Eggermont. 2009. “Half-precessional Dynamics of Monsoon Rainfall Near the East African Equator.” Nature 462 (7273): 637–641.
APA
Verschuren, D., Damsté, J. S. S., Moernaut, J., Kristen, I., Blaauw, M., Fagot, M., Haug, G. H., et al. (2009). Half-precessional dynamics of monsoon rainfall near the East African Equator. NATURE, 462(7273), 637–641.
Vancouver
1.
Verschuren D, Damsté JSS, Moernaut J, Kristen I, Blaauw M, Fagot M, et al. Half-precessional dynamics of monsoon rainfall near the East African Equator. NATURE. 2009;462(7273):637–41.
MLA
Verschuren, Dirk, Jaap S Sinninghe Damsté, Jasper Moernaut, et al. “Half-precessional Dynamics of Monsoon Rainfall Near the East African Equator.” NATURE 462.7273 (2009): 637–641. Print.