نتایج جستجو برای: holocene
تعداد نتایج: 8437 فیلتر نتایج به سال:
32 (Paleo-)climatologists are challenged to identify mechanisms that cause the 33 observed abrupt Holocene monsoon events despite the fact that monsoonal 34 circulation is assumed to be driven by gradual insolation changes. Here we provide 35 proxy and model evidence to show that moisture-advection feedback can lead to a 36 non-linear relationship between sea-surface and continental temperature...
[1] Global upper ocean evolution in the Holocene is studied in two coupled ocean-atmosphere models under orbital forcing conditions at 3, 6, 8, and 11 ka. The annual mean sea surface temperature (SST) changes in the early to mid-Holocene are found to be forced mainly by the annual mean insolation forcing with an overall symmetric response of colder equator (<0.5 C)/warmer high latitudes (<0.4 C...
We present a high-resolution magnesium/calcium proxy record of Holocene sea surface temperature (SST) from off the west coast of Baja California Sur, Mexico, a region where interannual SST variability is dominated today by the influence of the El Niño-Southern Oscillation (ENSO). Temperatures were lowest during the early to middle Holocene, consistent with documented eastern equatorial Pacific ...
Recent speleothem records from the tropics of both hemispheres document a gradual decrease in the intensity of the monsoons in the Northern Hemisphere and increase in the Southern Hemisphere monsoons over the Holocene. These changes are a direct response of the monsoons to precessiondriven insolation variability. With regard to atmospheric methane, this shift should result in a decrease in Nort...
This paper present a high resolution record of paleostorm events in the French Mediterrannean coast over the past 7000 years based on a long sediment core from lagoonal environment in Gulf of Lions. Using a multi-proxies approach on core associating grain size, faunal analysis, with a chronology derived from radiocarbon dates, we reconstruct Mid to Late Holocene history of backbarrier deposits ...
The margin of the Greenland Ice Sheet retreated rapidly during the first few thousand years of the Holocene. During this period of relative warmth, known as the Holocene thermal maximum, ice core records identify a significant short-lived cooling event at approximately 8.4–8.0 ka cal. yr BP (the ‘GH-8.2 event’) associated with a 5–7 1C fall in mean annual air temperature over the centre of the ...
We present fossil pollen data and discuss their climatic interpretations from a 688-cm-long sediment core from Hurleg Lake, a freshwater lake located in the Qaidam Basin on the NE Tibetan Plateau, just beyond the northern limit of the East Asian summer monsoon influence. The reconstruction of the Holocene vegetation and climate history was aided by modern surface pollen analysis. The 14000-yr c...
Magnetic property has been proved to be a sensitive proxy to climate change for both terrestrial and marine sediments. Based on the schedule frame established by AMS 14C dating of foraminifera, detail magnetic analyses were performed for core PC24 sediments at sampling intervals of 2 cm to discuss magnetic sensitivity of marine sediment to climate during Holocene for the northern South China Se...
Given the fact that the estimated present-day carbon storage of Northern Peatlands (NP) is about 300-500 petagram (PgC, 1 petagram = 10 gram), and the NP has been subject to a slow but persistent growth over the Holocene epoch, it is desirable to include the NP in studies of Holocene carbon cycle dynamics. Here we use an Earth system Model of Intermediate Complexity to study the first-order eff...
Although the recent historical period is usually treated as a temporal base-line for understanding patterns of mammal extinction, mammalian biodiversity loss has also taken place throughout the Late Quaternary. We explore the spatial, taxonomic and phylogenetic patterns of 241 mammal species extinctions known to have occurred during the Holocene up to the present day. To assess whether our unde...
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