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天气现象霜形成的有利条件和观测技巧 总被引:1,自引:0,他引:1
根据多年的地面气象观测经验和资料统计分析,对有利于形成天气现象"霜"的天气条件及观测环境进行综合分析,归纳总结出一些冬季观测霜的技巧。当测站受寒潮或强冷空气影响时,过程中期(云层消散1-2 d后)最易出现霜;一般情况下,干枯的草面上比生长着的草面上更易形成霜;背风处比迎风处易形成霜。观测时要重点查看背风处及低洼处的草面,尤其是干草面是否有霜形成;夜间可用手电筒照看草面,若有霜,草面上会有一些闪闪发亮的现象,再用手触摸草面,会有一种发硬的感觉。天亮后至日出前,要全面查看一遍观测场及视区内的近地物体上是否有霜,以避免日出后轻霜快速融化而漏记录霜。 相似文献
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Cyanothece sp. 113 is a unicellular, aerobic, diazotrophic and photosynthetic marine cyanobacterium. The optimal medium for exopolysaccharide yield by the strain was 70.0 g/L of NaCl, and 0.9 g/L of MgSO4 based on the modified F/2 medium for cultivation of marine algae. The optimal cultivation condition for exopolysaccharide yield by this cyanobacterial strain was 29°C, aeration, and continuous illumination at 86.0 μE/M2/S. Under the optimal conditions, over 18.4 g/L of exopolysaccharide was produced within 12 days. This was so far the highest exopolysaccharide yield produced with strains of Cyanothece sp. obtained. 相似文献
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