scholarly journals Climate in continental interior Asia during the longest interglacial of the past 500 000 years: the new MIS 11 records from Lake Baikal, SE Siberia

2010 ◽  
Vol 6 (1) ◽  
pp. 31-48 ◽  
Author(s):  
A. A. Prokopenko ◽  
E. V. Bezrukova ◽  
G. K. Khursevich ◽  
E. P. Solotchina ◽  
M. I. Kuzmin ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Regional Climate ◽  
The Holocene ◽  
Proxy Records ◽  
Peak Structure ◽  
Depositional Settings ◽  
Taiga Forest ◽  
Autochthonous Organic Matter ◽  
Study Sites ◽  
High Level

Abstract. A synthesis of paleoclimate responses from Lake Baikal during the MIS 11 interglacial is presented based on proxy records from two drill sites 245 km apart. BDP-99 is located in vicinity of the delta of the major Baikal tributary, whereas the BDP-96 site represents hemipelagic setting distant from riverine influence. The comparison of thicknesses of interglacial intervals in these contrasting depositional settings confirms the extended ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom biostratigraphic record matches that of the BDP-96-2 holostratotype and thus allows establishing establishes robust correlation between the records on the same orbitally-tuned timescale. The first detailed MIS 11 palynological record from the BDP-99 drill core indicates the dominance of boreal conifer (taiga) forest vegetation in the Baikal region throughout the MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The interval ca. 420–405 ka stands out as a "conifer optimum" with abundant Abies sibirica, indicative of climate significantly warmer and less continental than today. The closest Baikal analog to this type of vegetation in the history of the current Holocene interglacial is at ca. 9–7 ka. The warm conifer phase lasted for ca. 15 kyr during MIS 11 interrupted by two millennial-scale cooling episodes at ca. 411–410 and 405–404 ka. Reconstructed annual precipitation of 450–550 mm/yr during the MIS 11 interglacial is by ca. 100 mm higher than during the Holocene; regional climate was less continental with warmer mean temperatures both in summer and in winter. At both drill sites, the two-peak structure of the MIS 11 diatom abundance profiles reflects the orbital signature of precession in the interglacial paleoclimate record of continental Eurasia. MIS 11 interglacial was characterized by the sustained high level of primary production and accumulation of autochthonous organic matter at both study sites. The responses of paleoclimate-sensitive indices in the mineralogy of the MIS 11 sediments in BDP-96-2 are consistent with those during the Holocene. Illitization of secondary clay minerals in the Baikal watershed was an important process, but it appears to have been subdued during the first half of the MIS 11, apparently due to elevated humidity and muted seasonality of regional climate.

scholarly journals Climate in continental interior Asia during the longest interglacial of the past 500 000 years: the new MIS 11 records from Lake Baikal, SE Siberia

2009 ◽  
Vol 5 (4) ◽  
pp. 1951-1988 ◽  
Author(s):  
A. A. Prokopenko ◽  
E. V. Bezrukova ◽  
G. K. Khursevich ◽  
E. P. Solotchina ◽  
M. I. Kuzmin
Keyword(s):  
Lake Baikal ◽  
Regional Climate ◽  
Proxy Records ◽  
Peak Structure ◽  
Depositional Settings ◽  
Taiga Forest ◽  
Autochthonous Organic Matter ◽  
Study Sites ◽  
High Level ◽  
Continental Interior

Abstract. A synthesis of paleoclimate responses from Lake Baikal during the MIS 11 interglacial is presented based on proxy records from two drill sites 245 km apart. BDP-99 is located in vicinity of the delta of the major Baikal tributary, whereas the BDP-96 site represents hemipelagic setting distant from riverine influence. The comparison of thicknesses of interglacial intervals in these contrasting depositional settings confirm the extended ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom biostratigraphic record matches that of the BDP-96-2 holostratotype and thus establishes robust correlation between the records on the same orbitally-tuned timescale. The first detailed MIS 11 palynological record from the BDP-99 drill core indicates the dominance of temperate boreal (taiga) forest vegetation in the Baikal region throughout the MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The interval ca. 420–405 ka stands out as a "conifer optimum" with abundant Abies sibirica, indicative of climate significantly warmer and less continental than today. The closest Baikal analog to this type of vegetation in the current interglacial is at ca. 8–6 ka in the mid-Holocene. The warm conifer phase lasted for ca. 15 ka during MIS 11 interrupted by two millennial-scale cooling episodes. At both drill sites, the two-peak structure of the MIS 11 diatom abundance profiles reflects the orbital signature of precession in the interglacial paleoclimate record of continental Eurasia. MIS 11 interglacial was characterized by the sustained high level of primary production and accumulation of autochthonous organic matter at both study sites. The responses of paleoclimate-sensitive indices in the mineralogy of the MIS 11 sediments in BDP-96-2 are consistent with those during the Holocene. Illitization of secondary clay minerals in the Baikal watershed was an important process, but it appears to have been subdued during the first half of the MIS 11, possibly due to elevated humidity and muted seasonality of regional climate.

The dynamics of Holocene monsoon based on meteoric 10Be at Kunlun Pass on the northeastern Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Peng Chen ◽  
Zhongbo Yu ◽  
Markus Czymzik ◽  
Ala Aldahan ◽  
Jinguo Wang ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Tibet Plateau ◽  
The Holocene ◽  
Proxy Records ◽  
Low Levels ◽  
High Level ◽  
Qinghai Tibet Plateau

<p>Multiple proxy records have been used for the understanding of environmental and climate changes during the Holocene. For the first time, we here measure meteoric <sup>10</sup>Be isotope of sediments from a drill core collected at the Kunlun Pass (KP) on the northeastern Qinghai-Tibet Plateau (NETP) to investigate mositure and atmospheric circulation changes during the Holocene. The <sup>10</sup>Be flux suggests relative low levels in the Early Holocene, followed by a sharp increase to high values at around 4 ka BP (4 ka BP = 4000 years before present). Afterwards, the <sup>10</sup>Be flux remains on a high level during the Late Holocene, but decreases slightly towards today. These <sup>10</sup>Be deposition patterns are compared to moisture changes in regions dominated by the Indian Summer Monsoon (ISM), East Asian Summer Monsoon (EASM), and the Westerlies. Different from the gradual changes in monsoon patterns, the <sup>10</sup>Be data reveal low levels during the Early Holocene until ~4 ka BP when an obvious increase was indicated and a relative high level continues to this day, which is relatively more in agreement with patterns of the Westerlies. This finding provides a new evidence for a shift in the dominant pattern of atmospheric circulation at the KP region from a more monsoonal one to one dominated by the Westerlies. Our results improve the understanding of non-stationary interactions and spatial relevance of the EASM, the ISM and the Westerlies on the Qinghai-Tibet Plateau.</p>

Paleoenvironmental proxy records from Lake Hovsgol, Mongolia, and a synthesis of Holocene climate change in the Lake Baikal watershed

2007 ◽  
Vol 68 (1) ◽  
pp. 2-17 ◽  
Author(s):  
Alexander A. Prokopenko ◽  
Galina K. Khursevich ◽  
Elena V. Bezrukova ◽  
Mikhail I. Kuzmin ◽  
Xavier Boes ◽  
...  
Keyword(s):  
Lake Baikal ◽  
Asian Summer Monsoon ◽  
Vegetation Changes ◽  
Terrestrial Vegetation ◽  
The Holocene ◽  
Proxy Records ◽  
Lake Hovsgol ◽  
Soil Temperatures ◽  
Paleoenvironmental Evolution ◽  
Paleoclimate Records

AbstractHere we discuss paleoenvironmental evolution in the Baikal region during the Holocene using new records of aquatic (diatom) and terrestrial vegetation changes from Hovsgol, Mongolia's largest and deepest lake. We reconcile previous contradictory Baikal timescales by constraining reservoir corrections of AMS dates on bulk sedimentary organic carbon. Synthesis of the Holocene records in the Baikal watershed reveals a northward progression in landscape/vegetation changes and an anti-phase behavior of diatom and biogenic silica proxies in neighboring rift lakes. In Lake Baikal, these proxies appear to be responsive to annual temperature increases after 6 ka, whereas in Lake Hovsgol they respond to higher precipitation/runoff from 11 to 7 ka. Unlike around Lake Baikal, warmer summers between 6 and 3.5 ka resulted in the decline, not expansion, of forest vegetation around Lake Hovsgol, apparently as a result of higher soil temperatures and lower moisture availability. The regional climatic proxy data are consistent with a series of 500-yr time slice Holocene GCM simulations for continental Eurasia. Our results allow reevaluation of the concepts of ‘the Holocene optimum’ and a ‘maximum of the Asian summer monsoon’, as applied to paleoclimate records from continental Asia.

scholarly journals Evaluation of the Consistency of Simultaneously Acquired Sentinel-2 and Landsat 8 Imagery on Plastic Covered Greenhouses

2020 ◽  
Vol 12 (12) ◽  
pp. 2015 ◽  
Author(s):  
Manuel Ángel Aguilar ◽  
Rafael Jiménez-Lao ◽  
Abderrahim Nemmaoui ◽  
Fernando José Aguilar ◽  
Dilek Koc-San ◽  
...  
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Coefficient Of Determination ◽  
Landsat 8 ◽  
Surface Reflectance ◽  
Remote Sensing Techniques ◽  
Image Pairs ◽  
Study Sites ◽  
High Level ◽  
Sentinel 2

Remote sensing techniques based on medium resolution satellite imagery are being widely applied for mapping plastic covered greenhouses (PCG). This article aims at testing the spectral consistency of surface reflectance values of Sentinel-2 MSI (S2 L2A) and Landsat 8 OLI (L8 L2 and the pansharpened and atmospherically corrected product from L1T product; L8 PANSH) data in PCG areas located in Spain, Morocco, Italy and Turkey. The six corresponding bands of S2 and L8, together with the normalized difference vegetation index (NDVI), were generated through an OBIA approach for each PCG study site. The coefficient of determination (r2) and the root mean square error (RMSE) were computed in sixteen cloud-free simultaneously acquired image pairs from the four study sites to evaluate the coherence between the two sensors. It was found that the S2 and L8 correlation (r2 > 0.840, RMSE < 9.917%) was quite good in most bands and NDVI. However, the correlation of the two sensors fluctuated between study sites, showing occasional sun glint effects on PCG roofs related to the sensor orbit and sun position. Moreover, higher surface reflectance discrepancies between L8 L2 and L8 PANSH data, mainly in the visible bands, were always observed in areas with high-level aerosol values derived from the aerosol quality band included in the L8 L2 product (SR aerosol). In this way, the consistency between L8 PANSH and S2 L2A was improved mainly in high-level aerosol areas according to the SR aerosol band.

Middle Holocene environmental reconstruction and climatic inferences through multi-proxy records from Seymareh lake sediments (Zagros Mts., Iran)

2021 ◽  
Author(s):  
Michele Delchiaro ◽  
Giulia Iacobucci ◽  
Francesco Troiani ◽  
Marta Della Seta ◽  
Paolo Ballato ◽  
...  
Keyword(s):  
Sedimentation Rate ◽  
Water Discharge ◽  
Sediment Supply ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The Holocene ◽  
Middle Holocene ◽  
Lake System ◽  
Proxy Records ◽  
The Impact

&lt;p&gt;The Seymareh landslide is the largest rock slope failure (44&amp;#8201;Gm&lt;sup&gt;3&lt;/sup&gt;) ever recorded on the exposed Earth surface. It detached &amp;#8764;10&amp;#8201;ka BP from the northeastern flank of the Kabir-Kuh anticline (Zagros Mts., Iran) originating the natural dam responsible for the formation of a three-lake system (Seymareh, Jaidar, and Balmak lakes, with an area of 259, 46, and 5 km&lt;sup&gt;2&lt;/sup&gt;, respectively). The lake system persisted for &amp;#8764;3000 yr during the Holocene before its emptying phase due to overflow. A sedimentation rate of 21&amp;#8201;mm&amp;#8201;yr&lt;sup&gt;&amp;#8722;1&lt;/sup&gt; was estimated for the Seymareh lacustrine deposits, which increased during the early stage of lake emptying because of enhanced sediment yield from the lake tributaries.&amp;#160;&lt;/p&gt;&lt;p&gt;To reconstruct the climatic and environmental impact on the lake infilling, we reviewed the geomorphology of the basins and combined the results with multi-proxy records from a 30 m thick lacustrine sequence in Seymareh Lake. Major analyses comprise grain size analysis, carbon and oxygen stable isotopes of carbonate-bearing sediments, and X-ray diffraction analysis of clay minerals.&lt;/p&gt;&lt;p&gt;Lake overflowing is largely accepted as the main response to variations in water discharge and sediment supply since the alternation from dry to wet phases enhances sediment mobilization along hillslopes decreasing the accommodation space in the downstream sedimentary basins. In this regard, during the early-middle Holocene, the Seymareh area, as well as the entire Middle East, was affected by short-term climate changes at the millennial-scale, as testified by both paleoecological and archaeological evidence. Indeed, several records from Iranian lakes (i.e., Mirabad, Zeribar, Urmia) well documented the temperature and the moisture conditions of the western Zagros Mountains during the Holocene. During the early Holocene, the precipitation remained low up to 6 ka BP, reaching the driest condition around 8-8.2 ka BP. The impact of this abrupt climate change is evident across West Asia, where the first large villages with domesticated cereals and sheeps disappeared, converting to small hamlets and starting habitat-tracking. As regards the Seymareh area, a more irregular distribution of rainfalls and their increasing seasonality may support rhexistasy conditions, during which the scarce vegetation cover enhances both the hillslope erosion and sedimentation rate in the basins, most likely contributing to the overflow of Seymareh Lake.&amp;#160;&lt;/p&gt;

scholarly journals Level of relics in high-mountain flora of isolated Fisht-Oshten Massif and Chernomorskaya Chain

2019 ◽  
pp. 21-29
Author(s):  
I. N. Timukhin ◽  
B. S. Tuniyev
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
High Mountain ◽  
The West ◽  
The Caucasus ◽  
The Holocene ◽  
Alpine Species ◽  
High Level ◽  
First Time ◽  
Relic Species

For the first time the level of relics of the high-mountain flora of the northwestern edge of the highlands of the Caucasus has been established. The Fisht-Oshten Massif and the Black Sea Chain have a uniquely high level of relics - 51.0% (617 species), with a predominance of Tertiary-relic species - Rt - 41.2% (498 species). The second largest representation is a group of Holocene relics - Rx - 7.3% (88 species), the minimum represented Pleistocene relics - Rg - 2.5% (31 species). The relic level of alpine species is one of the highest in the Caucasus and is 52.8% (338 species). Alpine species also have predominance of Pliocene relics - 46.7% (299 species), the number of glacial relics is 2.5% (16 species), the share of xerothermic relics - 3.6% (23 species). In the preservation of relic species revealed general trends, depending on the remoteness of local flora from the main diaspora on the Fisht-Oshten Massif and the modern area of the meadow belt. These trends persist in Tertiary relics, while other patterns are observed for glacial and Holocene relics. The number of glacial relics fades to the west, most clearly it can be seen in alpine species. The number of Holocene relics as much as possible on the edge areas (Fisht-Oshten Massif and Mt. Semashkho) and minimally on the central peaks of the Black Sea Chain, where the Holocene expansion of xerophyte plants was insignificant.

scholarly journals Evidence of a prolonged drought ca. 4200 yr BP correlated with prehistoric settlement abandonment from the Gueldaman GLD1 Cave, N-Algeria

2015 ◽  
Vol 11 (4) ◽  
pp. 2729-2762 ◽  
Author(s):  
J. Ruan ◽  
F. Kherbouche ◽  
D. Genty ◽  
D. Blamart ◽  
H. Cheng ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Regional Climate ◽  
Faunal Remains ◽  
Human Occupation ◽  
Carbon And Oxygen Isotopes ◽  
Proxy Records ◽  
Prolonged Drought ◽  
The Mediterranean ◽  
Paleoclimate Records ◽  
Settlement Abandonment

Abstract. Middle Holocene cultures have been widely studied round the E-Mediterranean basin in the last 30 years and past cultural activities have been commonly linked with regional climate changes. However, in many cases such linkage is equivocal, in part due to existing climatic evidence that has been derived from areas outside the distribution of ancient settlements, leading to uncertainty from complex spatial heterogeneity in both climate and demography. A few high-resolution well-dated paleoclimate records were recently established using speleothems in the Central and E-Mediterranean basin, however, the scarcity of such records in the western part of the Mediterranean prevents us from correlating past climate evolutions across the basin and deciphering climate–culture relation at fine time scales. Here we report the first decadal-resolved Mid-Holocene climate proxy records from the W-Mediterranean basin based on the stable carbon and oxygen isotopes analyses of two U/Th dated stalagmites from the Gueldaman GLD1 Cave in N-Algeria. Comparison of our records with those from Italy and Israel reveals synchronous (multi) centennial dry phases centered at ca. 5600, ca. 5200 and ca. 4200 yr BP across the Mediterranean basin. New calibrated radiocarbon dating constrains reasonably well the age of rich anthropogenic deposits (e.g., faunal remains, pottery, charcoal) excavated inside the cave, which allows the comparison between in situ evidence of human occupation and of climate change. This approach shows that the timing of a prolonged drought at ca. 4400–3800 yr BP blankets the onset of cave abandonment shortly after ca. 4403 cal yr BP, supporting the hypothesis that a climate anomaly may have played a role in this cultural disruption.

scholarly journals Can Agroforestry Farmers Attain Sustainability? Case of Farmers in Selected Upland Farming Communities in the Philippines

2017 ◽  
Vol 5 (2) ◽  
pp. 101
Author(s):  
Leila Dimayuga Landicho ◽  
Josefina T. Dizon ◽  
Agnes C. Rola ◽  
Maria Ana T. Quinbo ◽  
Rowena DT. Baconguis
Keyword(s):  
Natural Capital ◽  
Household Survey ◽  
The Philippines ◽  
Multiple Cropping ◽  
Research Results ◽  
Farming Communities ◽  
Community Capitals ◽  
Conservation Farming ◽  
Study Sites ◽  
High Level

This article is based on the study which investigated the socioeconomic and biophysical conditions of the upland farming communities in the Philippines; identified the development pathways that were undertaken by the upland farmers; and determined level of sustainability of the upland farming communities on the basis of their development pathways. This article argues that agroforestry farmers in upland farming communities in the Philippines can attain sustainability. This argument is based on the study conducted in the three pilot upland communities of the Conservation Farming Villages program in Albay, Ifugao and Negros Oriental, Philippines. From seven focus group discussions (FGDs) with at least 12 participants per FGD for a total of 147 farmers, and farm household survey of 230 upland farmers, research results indicate that agroforestry farmers in the three study sites were smallholders and were cultivating in areas with marginal conditions. There were five development pathways identified. These are monocropping in contour, multiple cropping in contour, agroforestry, agroforestry with non-farm activities, and multiple cropping/monocropping without contour. With the community capitals framework as the theoretical foundation, analysis indicated that the five development pathways contributed to a high level of social, human and political capitals having mean scores of 0.73, 0.55 and 0.54, respectively; a moderate level of physical, financial and natural capital, with mean scores of 0.23, 0.20 and 0.23, respectively; and a very low level of cultural capital with mean score of -0.08. At the community level, on the other hand, research results revealed that the CFV sites in Ligao, Albay and La Libertad, Negros Oriental have almost similar contributions to the sustainability of the upland farming communities, while Alfonso Lista, Ifugao had the lowest. Thus, institutional arrangements with the farmers’ association and the local government units also played a key role in the sustainability of the upland farming communities. These results imply the need for a holistic and collaborative engagement towards attaining sustainable upland farming communities.

Model Estimates of Global and Regional Climate Changes in the Holocene

2020 ◽  
Vol 490 (1) ◽  
pp. 23-27 ◽  
Author(s):  
I. I. Mokhov ◽  
A. V. Eliseev ◽  
V. V. Guryanov
Keyword(s):  
Climate Changes ◽  
Regional Climate ◽  
The Holocene

scholarly journals High-resolution mineral dust and sea ice proxy records from the Talos Dome ice core

2013 ◽  
Vol 9 (6) ◽  
pp. 2789-2807 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
P. R. Kaufmann ◽  
S. Albani ◽  
C. Barbante ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Transport Model ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Last Interglacial ◽  
The Holocene ◽  
Proxy Records

Abstract. In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the Southern Ocean. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.

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