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Past intervals of warming provide the unique opportunity to observe how the East Asia monsoon precipitation response happened in a warming world. However, the available evaluations are primarily limited to the last glacial-to-interglacial warming, which has fundamental differences from the current interglacial warming, particularly in changes in ice volume. Comparative paleoclimate studies of earlier warm interglacial periods can provide more realistic analogs. Here, we present high-resolution quantitative reconstructions of temperature and precipitation from north-central China over the past 800 thousand years. We found that the average precipitation increase, estimated by the interglacial data, was only around one-half of that estimated for the glacialto-interglacial data, which is attributed to the amplification of climate change by ice volume variations. Analysis of the interglacial data suggests an increase in monsoon precipitation of ~100 mm for a warming level of 2°C on the Chinese Loess Plateau. [ABSTRACT FROM AUTHOR]

Chinese loess-paleosol sequences have long been regarded as the continental counterpart of deep-sea sediments in terms of their record of the Quaternary glacial--interglacial cycles. However, absolute chronologies for loess-paleosol sequences older than ca. 130 ka on the Chinese Loess Plateau are scarce. We conducted the first high-resolution luminescence dating, extending back to 350 ka, of the classical Luochuan loess section of the central Chinese Loess Plateau. Bacon age-depth modeling of the luminescence ages was used to obtain an age framework. The results indicate that on orbital timescales, loess accumulation at Luochuan was continuous over the last three glacial--interglacial cycles. The new age framework resolves discrepancies between orbitally tuned age models at several boundaries and provides new evidence supporting the reassignment of the Marine Isotope Stage 8/9 boundary age from 300 ka to ca. 280 ka. Our results also suggest that published astronomical timescales for the loess deposits of the Chinese Loess Plateau over the last ~2.6 m.y. are probably broadly reliable, as are the related regional and global climatic interpretations. [ABSTRACT FROM AUTHOR]

East Asian winter monsoon (EAWM) activity has had profound effects on environmental change throughout East Asia and the western Pacific. Much attention has been paid to Quaternary EAWM evolution, while long-term EAWM fluctuation characteristics and drivers remain unclear, particularly during the late Miocene when marked global climate and Asian paleogeographic changes occurred. To clarify understanding of late Miocene EAWM evolution, we developed a high-precision 9-million-year-long stacked EAWM record from Northwest Pacific Ocean abyssal sediments based on environmental magnetism, sedimentology, and geochemistry, which reveals a strengthened late Miocene EAWM. Our paleoclimate simulations also indicate that atmospheric CO2 decline played a vital role in this EAWM intensification over the Northwest Pacific Ocean compared to other factors, including central Asian orogenic belt and northeastern Tibetan Plateau uplift and Antarctic ice-sheet expansion. Our results expand understanding of EAWM evolution from inland areas to the open ocean and indicate the importance of atmospheric CO2 fluctuations on past EAWM variability over large spatial scales. [ABSTRACT FROM AUTHOR]

Using a combination of particle size analysis, magnetic measurements, scanning electron microscopy and transmission electron microscopy imaging, this study shows that in a wide range of depositional environments, there is a strong link between particle size classes and magnetic response, especially below the upper limit of stable single domain magnetic behaviour. Ferrimagnetic grain assemblages dominated by stable single domain magnetosomes regularly have peak susceptibility and remanence values in coarser grades than do those containing finer-grained, viscous and superparamagnetic secondary magnetic minerals formed during pedogenesis. This effect is despite the fact that there is a one to two orders of magnitude size difference between the particle size boundaries (at 1 or 2 μm) and key domain state transitions (mostly below 0·05 μm). The implications of these results are explored using samples spanning 22 Myr of loess accumulation on the Chinese Loess Plateau. The results from the loess sections, complemented by data from low-temperature magnetic experiments, show that there are subtle distinctions in mean ferrimagnetic grain-size between the Pleistocene and Miocene parts of the record, thus allowing more refined rock magnetic interpretations of the fine-grained ferrimagnetic mineral assemblages arising from the effects of weathering, pedogenesis and possibly diagenesis in the sections studied. [ABSTRACT FROM AUTHOR]

Provides information on a study regarding the importance of trajectory parameters of saltating sand grains in forming the kinetic theory of wind-sand current. Methodology; Theoretical analysis and experimental results; Conclusion.

The North Atlantic jet stream (NAJ) has a profound impact on the climate of the North Atlantic-European sector, especially in winter. Observations show that the winter NAJ (NAJw) has strengthened over the past ~140 yr. However, it remains unclear whether this long-term trend has deviated from the natural variability. Here, we present a 2500-yr-long reconstruction of NAJw strength using high-quality stalagmite δ18O records from southeastern Europe. Our results show that the NAJw weakened during both the Roman Warm Period (300 B.C.- A.D. 200) and the Medieval Warm Period (A.D. 900-1250) but that it has strengthened under anthropogenic warming (since A.D. 1850). This indicates that its current trend has already deviated from the natural variability. The best explanation for this present anomalous trend of NAJw strength is that it was triggered by the appearance of the North Atlantic warming hole under anthropogenic forcing. This anomalous trend suggests that continued global warming may further strengthen the NAJw in the future. [ABSTRACT FROM AUTHOR]

The origin and provenance of eolian sediments such as loess can potentially reveal paleo-air circulation directions that drive temporal changes in climate. The provenance of these deposits has been mostly assessed by detrital zircon U-Pb geochronology and remains debated. Recent studies reveal that constraining sediment provenance using only detrital zircon yields a restricted view of the overall sediment sources, because zircon commonly records high-temperature tectonothermal events and thus only represents a portion of provenance lithologies. We applied a new strategy for constraining the provenance of eolian sediments from the Chinese Loess Plateau--Earth's most extensive loess deposit--by using a multi-proxy (i.e., zircon, monazite and rutile) U/Th-Pb geochronology approach. We show that while zircon U-Pb-Lu-Hf isotopic data cannot conclusively discriminate the potential sources, monazite and rutile grains display dominant U/Th-Pb age peaks in the early Paleozoic, early Mesozoic, and late Cenozoic, mirroring the orogenic episodes of the northeast Tibetan Plateau. Monazite and rutile records also reveal spatial variability in sediment provenance between the western and central parts of the Chinese Loess Plateau, which is potentially affected by dust transport from westerly/northwesterly winds. Our integrated data set provides diagnostic constraints on the dust source, provenance variability, and transportation trajectory of the Chinese Loess Plateau, and highlights the importance of this new approach to provenance study of eolian deposits worldwide. [ABSTRACT FROM AUTHOR]

Recently, the first late Miocene-Pliocene eolian deposits from the western Chinese Loess Plateau have been reported. These deposits would complement the eolian record between Quaternary loess-paleosol sequences and Miocene loess sequences, if their wind-blown origin could be documented. However, although several lines of evidence indicate the eolian origin of this sequence, it is still necessary to address this issue through further efforts. Among these, biological approaches are of particular value. Here we analyze the composition and preservation conditions of mollusk assemblages in the Dongwan section. Our results show that all mollusk fossil individuals are preserved in perfect condition without indicating any reworking. All identifiable mollusk species are terrestrial, and are mostly identical to those identified in the Quaternary loess-paleosol sequences of the Chinese Loess Plateau. Generally, the cold-aridiphilous species are dominant in the loess layers, while thermo-humidiphilous species are mostly encountered in the paleosols. The close similarity of the mollusk record in both the Dongwan late Miocene-Pliocene deposits and the Quaternary loess sequence in the Chinese Loess Plateau supports the supposition that the Dongwan section is a typical loess-paleosol sequence, and is, without any doubt, of wind-blown origin. [ABSTRACT FROM AUTHOR]

We have proposed a method for super-resolution imaging using an interlayer cascaded structure comprising two metamaterial lenses. The metamaterial lenses are designed using the effective medium theory. The lens structures consist of two different planar dielectric films alternated with similar thin metallic films, making a diverging and converging lens. With this two-lens system, an image is formed at the output surface of the lens with subwavelength resolution. We have shown, through numerical simulations and an analytical approach, that an image with resolution nine times smaller than the light wavelength (365 nm) is achievable with this metamaterial lens system. The loss during transmission through the lens system is smaller compared with the hyperlens configuration with a similar design. [ABSTRACT FROM AUTHOR]