分类： 地球科学 >> 地理学 提交时间： 2023-03-19 合作期刊: 《干旱区科学》
摘要：Extreme precipitation events are one of the most dangerous hydrometeorological disasters, often resulting in significant human and socio-economic losses worldwide. It is therefore important to use current global climate models to project future changes in precipitation extremes. The present study aims to assess the future changes in precipitation extremes over South Asia from the Coupled Model Intercomparison Project Phase 6 (CMIP6) Global Climate Models (GCMs). The results were derived using the modified Mann-Kendall test, Sen's slope estimator, student's t-test, and probability density function approach. Eight extreme precipitation indices were assessed, including wet days (RR1mm), heavy precipitation days (RR10mm), very heavy precipitation days (RR20mm), severe precipitation days (RR50mm), consecutive wet days (CWD), consecutive dry days (CDD), maximum 5-day precipitation amount (RX5day), and simple daily intensity index (SDII). The future changes were estimated in two time periods for the 21st century (i.e., near future (NF; 2021–2060) and far future (FF; 2061–2100)) under two Shared Socioeconomic Pathway (SSP) scenarios (SSP2-4.5 and SSP5-8.5). The results suggest increases in the frequency and intensity of extreme precipitation indices under the SSP5-8.5 scenario towards the end of the 21st century (2061–2100). Moreover, from the results of multimodel ensemble means (MMEMs), extreme precipitation indices of RR1mm, RR10mm, RR20mm, CWD, and SDII demonstrate remarkable increases in the FF period under the SSP5-8.5 scenario. The spatial distribution of extreme precipitation indices shows intensification over the eastern part of South Asia compared to the western part. The probability density function of extreme precipitation indices suggests a frequent (intense) occurrence of precipitation extremes in the FF period under the SSP5-8.5 scenario, with values up to 35.00 d for RR1mm and 25.00–35.00 d for CWD. The potential impacts of heavy precipitation can pose serious challenges to the study area regarding flooding, soil erosion, water resource management, food security, and agriculture development.
分类： 地球科学 >> 地质学 提交时间： 2017-08-11 合作期刊: 《古脊椎动物学报》
摘要： This paper describes some micromammal fossils which were excavated from the South Longyadong Cave in the Luonan Basin, eastern Qinling Mountains of Shaanxi Province, central China. The fauna include 15 mammals consisting by Scapanulus oweni, Nasillus andersoni, Uropsilinae gen. et sp. indet., Soriculus sp., Ochotona cf. O. alpina, Belomys parapearsoni, Allocricetus ehiki, Proedromys bedfordi, Allophaiomys deucalion, Eospalax sp., Niviventer preconfucianus, Apodemus asianicus, Apodemus sp., Hystrix brachyura subcristata, Trogontherium cuvieri. Among them, the Nasillus andersoni and the Ochotona cf. O. alpina are the newly discovered fossil species. The fossil assemblage characteristics of newly micromammal faunal is similar to the North Longyadong Cave Fauna, and the geological age should not be later than early Middle Pleistocene. It might be a fauna of late Early Pleistocene. But in recent years, the thermoluminescence age of fossiliferous strata corresponding are 356.6±17.8 kaBP, 273.9±13.7 kaBP and 210.5±10.5 kaBP. The fauna is including both the south and the north animals, the animal combination obviously has the characteristics of the transition between the south and the north of China. 描述了1995~1997年东秦岭山地洛南盆地龙牙南洞洞穴遗址中发掘出土的小哺乳动物化石，包括甘肃鼹Scapanulus oweni, 峨眉鼩鼹Nasillus andersoni, 鼩鼹(属种未定) Uropsilinae gen. et sp. indet., 长尾鼩鼱Soriculus sp., 似高山鼠兔Ochotona cf. O. alpina, 偏皮氏毛耳飞鼠Belomys parapearsoni, 艾克氏异仓鼠Allocricetus ehiki, 沟牙田鼠Proedromys bedfordi, 欧洲异费鼠Allophaiomys deucalion, 始鼢鼠Eospalax sp., 先社鼠Niviventer preconfucianus, 亚洲姬鼠Apodemus asianicus, 姬鼠Apodemus sp., 马来豪猪(华南亚种) Hystrix brachyura subcristata, 居氏大河狸Trogontherium cuvieri等。该动物群同时包括南方型和北方型动物，其动物组合具有明显的南北过渡地带的特征。其中峨眉鼩鼹和似高山鼠兔为新发现的化石种。新发现的小哺乳动物化石组合类似于龙牙北洞，显示出比较古老的性质，时代上多为早更新世晚期或中更新世早期，但龙牙南洞遗址含化石地层对应的热释光(TL)年龄结果分别为(356.6±7.8) kaBP, (273.9±3.7) kaBP和(210.5±0.5) kaBP, 最近新的回授光释光(TT-OSL)测年数据进一步验证了热释光测年结果，获得的地层年代亦为距今40~20万年左右。
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