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每年夏天,各地都会举办各种形式的夏令营。其中,到大自然广阔天地去的生物夏令营最受广大青少年的欢迎,也最符合夏令营的初衷。因为夏令营的初衷就是让学生在紧张学习一学年,并且在完成升级或毕业考试之后,利用夏天草木生长最为茂盛葳蕤、鸟虫活动最为活跃密集、天气最为适合等条件,让学生投身大自然的怀抱。在那里,他们可以从自然界学到很多书本上学不到的鲜活知识; 相似文献
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Numerical simulation of the dual-core structure of the Bohai Sea cold bottom water in summer 总被引:1,自引:0,他引:1
Regional Ocean Modeling Systems (ROMS 3.0) and the k-ε turbulence closure scheme has been applied to investigating the seasonal evolution of the thermsocline in the Bohai Sea. The simulation re- produces the stratifications lasting from early April to early September and reveals the existence of marked Asymmetric Dual-Core Cold Bottom Water (ADCCBW) in the south and north depression basin respectively under the thermocline. The bottom temperature in the north depression is about 1--4℃ lower than that in the south depression basin which is in good agreement with observations. Model results suggest that the local bathymetry characteristics and inhomogeneous net heat flux due to the latitude difference are the major cause for the early formation of the ADCCBW. Numerical Lagrangian drifter experiments support the finding that the ADCCBW is maintained throughout the stratification periods by the inflow of cold bottom water from the northern Yellow Sea and deep channel in the western side of Liaodong Peninsula. The inflow cold water contributes to the north depression basin distinctively larger than to the south one. Tidal mixing enhances the bottom temperature asymmetry between the two basins. 相似文献
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难道夏天提前到来了?明明才五月初,许多地方的气温却已经达到30℃,热得人们恨不得直接穿上短袖衫。千万别急!五月,依据气候规律,我国大多数地区都还处在暮春时段,日最高气温可达30℃,但日平均气温却只有20℃左右,常常是"早晚凉,中午热",并没有达到气候意义上的夏季标准,因此不能当真正的夏天来对待。 相似文献
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