The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru
This paper serves two purposes: to review current ideas about the nature and forcing of decadal to millennial scale precipitation variation in the southern tropics of South America during the late Quaternary and to present a new methodology for the reconstruction of precipitation as applied to a Hol...
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ftunivnebraskali:oai:digitalcommons.unl.edu:geosciencefacpub-1244 2023-11-12T04:22:48+01:00 The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru Baker, Paul A. Fritz, Sherilyn C. Burns, Stephen J. Ekdahl, Erik Rigsby, CAtherine A. 2009-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/geosciencefacpub/243 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1244/viewcontent/Fritz_PCVSASR_2009_Nature_and_Origin__DC_VERSION.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/geosciencefacpub/243 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1244/viewcontent/Fritz_PCVSASR_2009_Nature_and_Origin__DC_VERSION.pdf Papers in the Earth and Atmospheric Sciences paleoclimate precipitation oxygen isotopes tropical South America Earth Sciences text 2009 ftunivnebraskali 2023-10-30T10:44:47Z This paper serves two purposes: to review current ideas about the nature and forcing of decadal to millennial scale precipitation variation in the southern tropics of South America during the late Quaternary and to present a new methodology for the reconstruction of precipitation as applied to a Holocene stable isotopic record of carbonate sediments in a tropical Andean lake, Lago Umayo, Peru. The basic thesis of the first part of the paper is that, although modern instrumental records suffice for deducing climate variability at decadal and shorter time scales, these records cannot adequately characterize the nature and forcing of lower-frequency climate variation. Understanding the nature of multi-decadal to millennial-scale climate variation and the mechanisms of large abrupt climate change is best derived from paleoclimatic time series. Tropical Atlantic sea-surface temperature variation is a significant control on tropical South American paleoclimate at these longer time scales. In the second part of the paper, an original method is presented for quantitatively reconstructing precipitation. This method utilizes the well-known relationship between the stable isotopic composition of precipitation and the amount of precipitation, a relationship that is highly significant in many tropical locales. Due to many simplifying assumptions, the reconstruction should be considered to be tentative. A ~12% increase in precipitation (~570 to 650 mm a–1) at 4750 cal year BP is consistent with the 6% increase in summer insolation at this latitude over the same period. However, the increase in precipitation was neither unidirectional nor gradual. Instead, every 240 years on average, precipitation increased or decreased by at least ~8% for periods lasting on average 100 years. The largest of these events had ~15% positive or negative departures from the long-term mean precipitation. These southern tropical wet events apparently coincided with periods of low sea-surface temperatures in the high-latitude North Atlantic, ... Text North Atlantic University of Nebraska-Lincoln: DigitalCommons@UNL |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
paleoclimate precipitation oxygen isotopes tropical South America Earth Sciences |
spellingShingle |
paleoclimate precipitation oxygen isotopes tropical South America Earth Sciences Baker, Paul A. Fritz, Sherilyn C. Burns, Stephen J. Ekdahl, Erik Rigsby, CAtherine A. The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
topic_facet |
paleoclimate precipitation oxygen isotopes tropical South America Earth Sciences |
description |
This paper serves two purposes: to review current ideas about the nature and forcing of decadal to millennial scale precipitation variation in the southern tropics of South America during the late Quaternary and to present a new methodology for the reconstruction of precipitation as applied to a Holocene stable isotopic record of carbonate sediments in a tropical Andean lake, Lago Umayo, Peru. The basic thesis of the first part of the paper is that, although modern instrumental records suffice for deducing climate variability at decadal and shorter time scales, these records cannot adequately characterize the nature and forcing of lower-frequency climate variation. Understanding the nature of multi-decadal to millennial-scale climate variation and the mechanisms of large abrupt climate change is best derived from paleoclimatic time series. Tropical Atlantic sea-surface temperature variation is a significant control on tropical South American paleoclimate at these longer time scales. In the second part of the paper, an original method is presented for quantitatively reconstructing precipitation. This method utilizes the well-known relationship between the stable isotopic composition of precipitation and the amount of precipitation, a relationship that is highly significant in many tropical locales. Due to many simplifying assumptions, the reconstruction should be considered to be tentative. A ~12% increase in precipitation (~570 to 650 mm a–1) at 4750 cal year BP is consistent with the 6% increase in summer insolation at this latitude over the same period. However, the increase in precipitation was neither unidirectional nor gradual. Instead, every 240 years on average, precipitation increased or decreased by at least ~8% for periods lasting on average 100 years. The largest of these events had ~15% positive or negative departures from the long-term mean precipitation. These southern tropical wet events apparently coincided with periods of low sea-surface temperatures in the high-latitude North Atlantic, ... |
format |
Text |
author |
Baker, Paul A. Fritz, Sherilyn C. Burns, Stephen J. Ekdahl, Erik Rigsby, CAtherine A. |
author_facet |
Baker, Paul A. Fritz, Sherilyn C. Burns, Stephen J. Ekdahl, Erik Rigsby, CAtherine A. |
author_sort |
Baker, Paul A. |
title |
The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
title_short |
The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
title_full |
The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
title_fullStr |
The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
title_full_unstemmed |
The Nature and Origin of Decadal to Millennial Scale Climate Variability in the Southern Tropics of South America: The Holocene Record of Lago Umayo, Peru |
title_sort |
nature and origin of decadal to millennial scale climate variability in the southern tropics of south america: the holocene record of lago umayo, peru |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2009 |
url |
https://digitalcommons.unl.edu/geosciencefacpub/243 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1244/viewcontent/Fritz_PCVSASR_2009_Nature_and_Origin__DC_VERSION.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Papers in the Earth and Atmospheric Sciences |
op_relation |
https://digitalcommons.unl.edu/geosciencefacpub/243 https://digitalcommons.unl.edu/context/geosciencefacpub/article/1244/viewcontent/Fritz_PCVSASR_2009_Nature_and_Origin__DC_VERSION.pdf |
_version_ |
1782337735918354432 |