Ice cores recovered from polar ice sheet received and preserved sulfuric acid fallout from explosive volcanic eruptions. DT263 ice core was retrieved from an east Antarctic location. The ice core is dated using a combination of annual layer counting and volcanic time stratigraphic horizon as 780 years (1215-1996 A.D.). The ice core record demonstrates that during the period of approximately 1460-1800 A.D., the accumulation is sharply lower than the levels prior to and after this period. This period coincides with the most recent neoglacial climatic episode, the "Little Ice Age (LIA)", that has been found in numerous Northern Hemisphere proxy and historic records.The non-sea-salt 2 4 SO − concentrations indicate seventeen volcanic events in DT263 ice core. Compared with those from previous Antarctic ice cores, significant discrepancies are found between these records in relative volcanic flux of several well-known events. The discrepancies among these records may be explained by the differences in surface topography, accumulation rate, snow drift and distribution which highlight the potential impact of local glaciology on ice core volcanic records, analytical techniques used for sulfate measurement, etc. Volcanic eruptions in middle and high southern latitudes affect volcanic records in Antarctic snow more intensively than those in the low latitudes.
[1] Chemical analysis of a shallow (82.5 m) ice core from a location (DT263) in the essentially unexplored area of Princess Elizabeth Land, East Antarctica, has been used to construct a continuous, high-resolution 780-year (AD 1207(AD -1996 glaciochemical record. During the twentieth century, snow accumulation rates and concentrations of chemical species in snow appear to be stable with short-term variations, indicating relatively stable and warm climatic conditions. The period of AD 1450-1850 in this record is characterized by sharply reduced snow accumulation rates and decreased concentrations of several chemical species that suffer postdepositional losses linked to very low accumulation rates. These characteristics are consistent with colder climatic conditions and suggest that this is likely a neoglacial episode. The timing of this episode coincides with the Little Ice Age (LIA), a relatively cold period in the Northern Hemisphere between the beginning of the fifteenth century and the end of the nineteenth century. Evidence in ice core and sedimentary records also indicates neoglacial conditions in some Southern Hemisphere locations during the general time frame of LIA. The DT263 record, along with a few published ice core records, points to the existence of an LIA-type climatic episode in Antarctica between the fifteenth century and the twentieth century. However, other Antarctic ice core records show no such evidence. Together, these records highlight the regional differences in Holocene climate variations in Antarctica. The DT263 record suggests that colder and drier conditions prevailed during the LIA time period at the eastern Indian Ocean sector of East Antarctica.
ABSTRACT. An ice core was extracted from the Zangser Kangri (ZK) ice field in the northern Tibetan Plateau (NTP), a location with limited instrumental and proxy records. In this paper, we present a continuous high-resolution dust concentration time series spanning the period AD 1951-2008 to investigate variations in atmospheric dust loading over the NTP. The results show that atmospheric dust loading exhibited significant decadal variations, with two periods of high dust loading (AD 1959-67 and AD 1979-89) and three periods of relatively low loading (AD 1951-58, AD 1968-78 and AD 1990-2008). The variability of atmospheric dust loading was related to wind speed at 500 hPa over the dust source regions. The winter Arctic Oscillation (AO) index showed a significant negative correlation with the annual dust concentration, implying a possible connection between the winter AO and the atmospheric dust loading over the NTP.
China is by far the world's largest producer and consumer of electricity. To reduce carbon emissions, the State Grid of China has deployed a project to transport energy resources from West China to East China through extra-high-voltage transmission lines. In the Loess Plateau, a broad region subjected to severe soil erosion and environmental sensitivity, the safety of transmission lines has been frequently threatened by natural hazards such as landslides and ground subsidence. However, building a monitoring network covering all the transmission lines to provide timely early warnings is prohibitively expensive, particularly for sparsely inhabited areas. Based on the large-scale coverage of Sentinel-1 SLC images in IW TOPS mode, we utilized persistent scatterer interferometry to measure the ground target movements along transmission lines with millimeter accuracy. Three regions of interest were selected to reflect the different environmental conditions from the south to north of the Yan'an Region. The displacement variations were compared and evaluated at three spatial scales (region, route, local) from October 2018 to November 2019. On the regional scale, the deformation variation decreased from the south (-35.51 -28.59 mm/yr) to north (-19.48 -20.18 mm/yr), which was significantly different as determined by ANOVA and can be attributed to the impacts of water-induced subsidies and human activities. On the local scale, the results showed that the deformation rate was less than 10.4 mm/yr, which suggested a stable status for the experimental line sections. The application of advanced InSAR technologies has bright prospects in smart grid implementation.
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