scholarly journals Spatial and temporal sea-surface temperatures in the eastern equatorial Pacific over the past 150 kyr

2006 ◽  
Vol 33 (13) ◽  
Author(s):  
Keiji Horikawa ◽  
Masao Minagawa ◽  
Masafumi Murayama ◽  
Yoshihisa Kato ◽  
Hirofumi Asahi
Keyword(s):  
Equatorial Pacific ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
The Past ◽  
Surface Temperatures ◽  
Eastern Equatorial Pacific

Cooling and freshening of the eastern equatorial Pacific over the last 2000 years

2020 ◽  
Author(s):  
Gerald Rustic ◽  
Athanasios Koutavas ◽  
Thomas Marchitto
Keyword(s):  
Stable Isotope ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Equatorial Pacific ◽  
Sea Surface ◽  
Eastern Pacific ◽  
Ice Age ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Eastern Equatorial Pacific

<p>Sea surface temperatures in the eastern equatorial Pacific exert powerful influence on the climate beyond the tropics through strong atmosphere-ocean coupling. Records of eastern Pacific sea surface temperatures are of vital importance for identifying the linkages between short-term climate variability and long-term climate trends. Here we reconstruct eastern equatorial Pacific sea surface temperature and salinity from paired trace metal and stable isotope analyses in foraminifera from a sediment core near the Galápagos Islands. Sea surface temperatures are correlated with reconstructed Northern and Southern hemisphere temperature records suggesting a common origin. We propose that this temperature signal originates in the extra-tropics and is transmitted to the eastern Pacific surface via its source waters. We find exceptions to this cooling during the Little Ice Age and during the last century, where notable sea surface temperature increases are observed. We calculate δ<sup>18</sup>O<sub>sw </sub>from paired stable isotope and trace element analyses and derive salinity, which reveals a significant trend toward fresher surface waters in the eastern equatorial Pacific. The overall trend toward cooler and fresher sea surface conditions is consistent with longer-term trends from both the Eastern and Western Pacific.</p>

Beyond Sea Surface Temperatures: a Holistic Approach to Addressing Pliocene Tropical Conditions

2020 ◽  
Author(s):  
Heather L. Ford ◽  
Natalie Burls ◽  
Deepak Chandan ◽  
Jonathan LaRiviere ◽  
Alexey Fedorov ◽  
...  
Keyword(s):  
Equatorial Pacific ◽  
Warm Period ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Eastern Equatorial Pacific ◽  
Equatorial Thermocline ◽  
Temperature Records ◽  
Subsurface Temperatures ◽  
Sst Gradient

<p>The tropical Pacific thermocline structure is critical to tropical sea surface temperatures (SSTs) and variability. During the mid-Pliocene warm period (~3 Ma), the zonal SST gradient was reduced due to relatively warm SST in the Eastern Equatorial Pacific; we call this mean state “El Padre.” How did the equatorial thermocline contribute to this reduced zonal SST gradient? Here we summarize published Mg/Ca (surface and subsurface dwelling foraminifera) and alkenone records and generate new SST estimates from Mg/Ca and alkenones. The subsurface dwelling <em>Globorotalia tumida</em> Mg/Ca-based temperature records from the eastern and western equatorial Pacific show mid-Pliocene warm period subsurface temperatures warmer than today; El Padre included a basin-wide thermocline that was relatively warm, deep, and weakly tilted. We compare the published and newly generated SST and subsurface temperature records to the Pliocene Modeling Intercomparison Project (PlioMIP1) and show that few models capture the magnitude and spatial pattern suggested by the temperature records. Those models that do corroborate the temperature records have warm subsurface temperatures in the Eastern Equatorial Pacific that dynamically link to warm SSTs in the cold tongue. This highlights the need to accurately model thermocline dynamics and mid-latitude conditions, where equatorial thermocline waters originate, in order to gain an understanding of the underlying processes that explain the mid-Pliocene warm period.</p>

scholarly journals Thirty thousand years of vegetation development and climate change in Angola (Ocean Drilling Program Site 1078)

2008 ◽  
Vol 4 (2) ◽  
pp. 107-124 ◽  
Author(s):  
L. M. Dupont ◽  
H. Behling ◽  
J.-H. Kim
Keyword(s):  
Rain Forest ◽  
Vegetation History ◽  
First Record ◽  
Dry Forest ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Miombo Woodlands ◽  
Vegetation Development ◽  
The Past ◽  
Surface Temperatures

Abstract. ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant.

Increasing aridity over the past 223 years in the Nepal Himalaya inferred from a tree-ring δ18O chronology

The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 809-817 ◽  
Author(s):  
Masaki Sano ◽  
R Ramesh ◽  
MS Sheshshayee ◽  
R Sukumar
Keyword(s):  
Tree Ring ◽  
Summer Monsoon ◽  
Function Analysis ◽  
Monsoon Season ◽  
Sea Surface ◽  
Drought Severity ◽  
Sea Surface Temperatures ◽  
Nepal Himalaya ◽  
The Past ◽  
Surface Temperatures

A tree-ring δ18O chronology of Abies spectabilis from the Nepal Himalaya was established to study hydroclimate in the summer monsoon season over the past 223 years (ad 1778–2000). Response function analysis with ambient climatic records revealed that tree-ring δ18O was primarily controlled by the amount of precipitation and relative humidity during the monsoon season (June–September). Since tree-ring δ18O was simultaneously correlated with temperature, drought history in the monsoon season was reconstructed by calibrating against the Palmer Drought Severity Index (PDSI). Our reconstruction that accounts for 33.7% of the PDSI variance shows a decreasing trend of precipitation/moisture over the past two centuries, and reduction of monsoon activity can be found across different proxy records from the Himalaya and Tibet. Spatial correlation analysis with global sea surface temperatures suggests that the tropical oceans play a role in modulating hydroclimate in the Nepal Himalaya. Although the dynamic mechanisms of the weakening trend of monsoon intensity still remain to be analyzed, rising sea surface temperatures over the tropical Pacific and Indian Ocean could be responsible for the reduction of summer monsoon.

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