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40~30 ka BP在过去被认为是末次冰期的间冰阶,温度稍高,但仍在冰期内.20世纪90年代西昆仑山古里雅冰芯记录研究首次指出,当时气温可能高出现代4℃,即为以前所不知的间冰期.追踪同期湖泊沉积,孢粉与古生物,黄土与沙漠地区古土壤,石灰岩洞穴中石笋,古河道,滨海地区海相沉积等多种记录,集成研究表明,当时青藏高原与西北干旱区有许多淡水大湖,降水量远比现代丰沛,导致外流水系扩大,如青海境内的黄河上游水系形成.暖湿的气候条下,森林分布区向北向西大范围扩展,华南热带喜湿热的陆均松(Dacrydiumsp.)北界移至22°~24°N,表明当时热带气温高于现代2℃左右,降水量也有较大增加.长江下游石笋资料和北方半干旱、半湿润区的植物、古土壤、河道沉积资料均表示降水增加,森林覆盖度大.由于冰川和极地冰盖萎缩,海平面上升,给合若干地区地面沉降,海河下游、长江三角洲和珠江三角洲均出现相当规模的海侵.上述涉及全中国的特殊暖湿环境的形成与地球轨道运行岁差周期变化导致中低纬度日射增强,致使温度升高,季风区与西风带降水量都有显著增加关系密切,而植被改善又对温度和湿度有正反馈作用.
40-30 ka BP was previously considered the interglacial ice stage of the last glacial period, with a slightly higher temperature but still within the ice age. For the first time, studies of the Gurliya ice core recorded in the West Kunlun Mountains in the 1990s showed that the temperature was probably higher than that of the modern age 4 ℃, which was previously unknown in the glacial period.Research on the records of lacustrine sediments, sporopollen and palaeontology, ancient soils in loess and desert areas, stalagmites in limestone caves, marine courses in ancient rivers and coastal areas, At that time, there were many freshwater lakes in the Qinghai-Tibet Plateau and the northwest arid region, with precipitation far more abundant than the modern ones, resulting in the expansion of outflowing water systems such as the upper reaches of the Yellow River in Qinghai. In the warm and humid climates, The northern boundary of Dacrydium sp. In South China tropical hot humid zone moved to 22 ° ~ 24 ° N, indicating that the tropical climate temperature was about 2 ℃ higher than that of the modern time and the precipitation also increased greatly.The stalagmite data in the lower reaches of the Yangtze River and the semi-arid and semi-humid The data of plant, paleosol and channel sediment in the area show that the precipitation is increased and the forest coverage is large, and the sea level rise due to the shrinkage of glaciers and polar ice sheets, the land subsidence in a number of areas, the lower reaches of the Haihe River, the long Delta and Pearl River Delta all experienced significant sea transgression.The formation of special warm and humid environment and the orbit change of Earth orbit during the above-mentioned period lead to the increase of solar radiation in the middle and low latitudes, resulting in the increase of temperature and the increase of both the monsoon and the westerly There is a significant increase in close relationship, while vegetation improvement has positive feedback on temperature and humidity.