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Lacustrine stable isotope record of precipitation changes in Nicaragua during the Little Ice Age and Medieval climate anomaly

Nathan D. Stansell, Byron A. Steinman, Mark B. Abbott, Michael Rubinov and Manuel Roman-Lacayo
Lacustrine stable isotope record of precipitation changes in Nicaragua during the Little Ice Age and Medieval climate anomaly
Geology (Boulder) (November 2012) 41 (2): 151-154

Abstract

Discerning the influences of the El Nino Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) on drought variability in the tropics during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA) will help to improve our understanding of climate system responses to internal and external forcing. Sediments from Lago El Gancho, Nicaragua, provide an approximately 1400 yr record of water balance (precipitation and evaporation) changes from a region that is sensitive to teleconnected Pacific and Atlantic ocean-atmosphere dynamics. Oxygen isotope values of ostracod carapaces (delta (super 18) O (sub ostracod) ) are consistently low in El Gancho sediments between ca. A.D. 950 and 1250, indicating that wetter conditions prevailed during the MCA, a period of La Nina-like mean state conditions in the tropical Pacific, and a positive mean state of the NAO. The approximately 150 yr period between the MCA and LIA was marked by an abrupt shift to persistently drier conditions at a time of highly variable Pacific sea-surface temperatures, and a transition toward a more negative NAO phase. In sediment from ca. A.D. 1450 to the present, delta (super 18) O (sub ostracod) values increase, suggesting that drier conditions persisted through most of the LIA, a time of a relatively negative NAO phase and El Nino-like mean state conditions in the tropical Pacific. The long-term precipitation trends inferred from the El Gancho data are not entirely consistent with modern associations between precipitation in the circum-Caribbean region and the NAO, suggesting that present-day hydroclimatic shifts resulting from variability in synoptic climate patterns are dissimilar to changes resulting from teleconnected ocean-atmosphere dynamics that operated during the MCA and LIA.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 41
Serial Issue: 2
Title: Lacustrine stable isotope record of precipitation changes in Nicaragua during the Little Ice Age and Medieval climate anomaly
Affiliation: University of Pittsburgh, Department of Geology and Planetary Science, Pittsburgh, PA, United States
Pages: 151-154
Published: 20121113
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 33
Accession Number: 2013-007360
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2013037
Illustration Description: illus. incl. sketch map
N11°55'00" - N11°55'00", W85°55'00" - W85°55'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201305
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