论文部分内容阅读
利用1979-2009年NCEP/CFSR全球大气边界层高度(PBLH)、感热通量月平均资料,运用多种统计方法,探讨了东亚地区大气边界层高度和感热通量的变化特征,并研究了两个要素场之间的相互关系.结果表明:夏季大气边界层高度东部增高、西部降低,而冬季则与夏季相反.夏季青藏高原地区感热有减少的趋势,其余地区以增加为主;冬季东部地区及新疆西部感热减少,其余地区感热增加.夏季奇异值分析第一模态表明青藏高原地区的感热通量减少时,相应地区的PBLH降低;内蒙古东部和东北地区的感热增加时,相应地区的PBLH增加.该空间型在一定程度上反映了青藏高原、内蒙古东部及东北地区,PBLH变化主要受地表加热影响,且年代际变化显著.夏季奇异值分析第二模态表明当青藏高原南侧、华北的感热增加(减少)时,相应地区的PBLH升高(降低),该空间型年际变化较显著,一定程度上反映了大气边界层高度及感热在高原主体及其南侧分布的差异.冬季奇异值分析第一模态主要表现为在我国东西部反相变化的分布;冬季奇异值分析第二模态表现为华北和华东地区与其余地区反相相关的分布.冬季两个空间型均具有一定的年代际变化特征.在青藏高原及其南侧和西北干旱半干旱区部分地区,PBLH变化主要受地表加热的影响,而在东部季风区,感热变化仅是影响PBLH变化的因素之一.“,”By using the monthly global planetary boundary layer height (PBLH) and sensible heat reanalysis data provided by the NCEP/CFSR,utilizing different statistical methods,the trend of the planetary boundary layer height and sensible heat are discussed.The relationships of PBLH and sensible heat have been studied with singular value decomposition (SVD).The results are showed as following.The trend of PBLH in summer increased in the east of eastern Asia,but decreased in the west of the region.The trend of PBLH in winter increased in the west of eastern Asia,but decreased in the east of the eastern Asia.In summer,the trend of sensible heat decreased in the Qinghai-Xizang Plateau but increased in the other regions.The trend of sensible heat in winter decreased in the Xinjiang region and the east of China,but increased in the east of the eastern Asia.In summer,the first mode of singular vectors (SVD1) is founded when the sensible heat reduced in the Qinghai-Xizang Plateau;the PBLH in the corresponding region reduced.When the sensible heat increased in the east of Inner Mongolia and the northeast China,the PBLH in the corresponding regions increased.The SVD1 is characteristic of interdecadal variation.For the SVD1,to a certain extent,the changes of PBLH in the Tibet Plateau,Eastern Inner Mongolia and Northeast China are mainly influenced by the surface heating.The SVD2 in summer shows when the sensible heat increased (or reduced) in the north of China and the south side of Qinghai-Xizang Plateau,the PBLH in the corresponding regions increased (or reduced).The SVD2 in summer is characteristic of interannul variation.This mode shows the difference of both PBLH and sensible heat in the region of the south side of the Qinghai-Xizang Plateau and that in the main body of the Qinghai-Xizang Plateau.In winter,the SVD1 shows the out-of-phase distribution between the regions of east of eastern Asia and west of eastern Asia.The SVD2 in winter shows the out-of-phase distribution between the both of the North and East China regions and the other regions.Those two of modes in winter are characteristic of interdecadal variations.In the region of the Qinghai-Xizang Plateau and its south side,and the arid and semi-arid region of northwest China,the PBLH changes are mainly influenced by surface heating,but in the eastern monsoon regions,the change of sensible heat is only one of the factors affecting the change of PBLH.