排序方式: 共有4条查询结果,搜索用时 0 毫秒
1
1.
针对副热带高压的动力预报模型难以准确构建的困难,基于T106数值预报产品500 hPa位势高度场序列,用经验正交函数(EOF)分解方法对位势场序列进行了时、空分解,引入了动力系统重构思想,以EOF分解的空间模态的时间系数序列作为动力模型变量,用遗传算法全局搜索和并行计算优势,进行了动力模型参数的优化反演,建立了客观合理的非线性动力模型.通过对动力模型积分和EOF的时、空重构,实现了副热带高压的中、长期预报.试验结果表明,本文反演的动力模型的副热带高压预报效果优于常规的数值预报产品,该研究工作为副热带高压等复杂天气系统和要素场预报提供了新的方法思路和技术途径. 相似文献
2.
地表动量和热量输送对全球气候和大气环流变化具有重要影响,Monin-ObukhoV(M-O)相似性函数是计算近地层动量和热量通量的重要手段,获得准确的总体输送系数是提高大气模式模拟能力的关键环节.本文利用锡林郭勒草原2008年春季近地层湍流通量观测资料,对M-O相似性函数进行了修订,拟合出了经验公式,并建立了10 m高度水平风速与动量总体输送系数和感热总体输送系数的关系.研究发现,修订的M-O相似性函数计算的湍流通量与涡旋相关法测量值相比,动量通量低估了10.8%,感热通量高估了6.5%Businger-Dyer通量廓线关系计算的湍流通量与涡旋相关法测量值相比,动量通量低估了37.0%,感热通量高估了16.1%.近地层大气层结不稳定时,动量总体输送系数与10 m高度水平风速满足关系CD=0.009u-0.322,感热总体输送系数与10 m高度水平风速满足CH=0.184U-1.978;近地层大气层结稳定时,总体输送系数与10 m高度水平风速符合对数规律,并随风速增大趋于中性或近中性.修订的M-O相似性函数可显著提高平均梯度观测资料计算草原下垫面湍流通量的准确性;总体输送系数与10 m高度水平风关系的建立.为描述草原下垫面湍流输送特征提供了可靠的参数化方案. 相似文献
3.
NON-LINEAR DYNAMIC MODEL RETRIEVAL OF SUBTROPICAL HIGH BASED ON EMPIRICAL ORTHOGONAL FUNCTION AND GENETIC ALGORITHM 总被引:1,自引:0,他引:1
Aiming at the difficulty of accurately constructing the dynamic model of subtropical high, based on the potential height field time series over 500 hPa layer of T106 numerical forecast products, by using EOF(empirical orthogonal function) temporal-spatial separation technique, the disassembled EOF time coefficients series were regarded as dynamical model variables, and dynamic system retrieval idea as well as genetic algorithm were introduced to make dynamical model parameters optimization search, then, a reasonable non-linear dynamic model of EOF time-coefficients was established. By dynamic model integral and EOF temporal-spatial components assembly, a mid-/long-term forecast of subtropical high was carried out. The experimental results show that the forecast results of dynamic model are superior to that of general numerical model forecast results. A new modeling idea and forecast technique is presented for diagnosing and forecasting such complicated weathers as subtropical high. 相似文献
4.
1