Regional representation of glaciers in Chandra Basin region,western Himalaya,India     

Pratima Pandey  S. Nawaz Ali  AL. Ramanathan  P.K. Champati ray  G. Venkataraman 《地学前缘(英文版)》2017,8(4):841-850

Hamtah and Chhota Shigri are two nearby, well monitored glaciers of western Himalaya, lying in the same climatic zone and driven by the same climatic conditions. In this study, topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier response. Further, their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the region. Multi sensor and multi temporal remote sensing data have been used to carry out to fulfill the objectives. It is found that being in the same climatic zone, the mean accumulation area ratio of Chhota Shigri is 54% and Hamtah is 11% between 1980 and 2014. In comparison to Hamtah, Chhota Shigri glacier has a small upslope area, low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar radiation. The analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah glacier. Also, the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations.  相似文献   

Historical deposits of Alexandrium catenella resting cysts in the sediments of Queen Charlotte Sound,New Zealand     

AL MacKenzie  S Webber  AM Watts  A Tonks 《新西兰海洋与淡水研究杂志》2016,50(2):195-208

In 2011, a large repository of resting cysts of the toxic dinoflagellate Alexandrium catenella was discovered in the sediments of the Onapua/Opua inlet located off Tory Channel, Queen Charlotte Sound. The inlet is a potential source of infection for other areas, such as the major mussel-growing areas of Port Underwood and Pelorus Sound. This study aimed to establish whether the dinoflagellate was a new arrival in the Sounds or had existed unnoticed in this isolated embayment for some time. Alexandrium catenella cysts were identified to a depth of 20–21?cm within the sediment cores, corresponding to a date estimated by radioisotope (²¹⁰Pb and ¹³⁷Cs) and Pinus radiata pollen distribution to at least the mid 1970s. Over this time span, resident populations of A. catenella have not become established beyond the confines of Queen Charlotte Sound, suggesting it does not pose an imminent threat of doing so unless increasingly intense and prolonged blooms result in more widespread cyst dispersal.  相似文献