华北汛期降水异常与100hPa高度场异常的关系

利用华北17站1951～2000年的逐月降水资料,与前期的100 hPa高度场(1958～1997年)求相关,找到了100 hPa高度场影响华北地区汛期降水的关键影响区为25°～35°N,85°～105°E,对应的关键影响时段为前一年3～5月.然后用SVD方法证实了前一年春季正是与华北汛期降水相关最显著的时段;而所选关键区正是处于一种范围更大的100 hPa高度场空间分布型的关键部位,而华北地区是关键区影响中国东部降水的最显著的区域之一.     

西安地区旱涝气候的长期变化

根据西安丰富的历史旱涝史料,建立了近１５００年旱涝序列,并采用滑动滤波、功率谱分析、谐波分析等方法,对西安地区旱涝气候的长期变化进行分析。     

陆面特征非均一作用参数化及其对区域气候影响的数值模拟试验

本文首先改进了陆地下垫面特征非均一性的次网格尺度参数化方法，然后利用三维地气耦合的区域气候模式，设计一系列值试验，研究了下垫面特征改变对区域气候环境变化的影响，主要分析了陆地表面特征变化对我国苏南附近地区夏季温度化的影响，结果表明采用地下垫面特征非均一作用的次网格尺度参数化方法对于改进数值模拟结果的质量有一定效果。     

Predictability in limited area and global models

Summary Selected small domain LAM forecasts modulated by highly corrugated underlying topography, and driven by different state-of-science outer models suggest that uncertain outer model guidance for LAMs produces large, domain averaged sensitivity. A further literature survey indicates that many LAM forecasts are relatively insensitive to details of the local initial state, and that mesoscales show slight error growth, in contradiction to classical predictability theory. A series of global predictability experiments is presented in order to reconcile the contradiction. The experiments imply that, even in baroclinically unstable atmospheres, the most common sources of local error growth are associated with small uncertainties of the larger spatial scales rather than small uncertainties of the smaller spatial scales. Variable resolution, real-data experiments of barotropic versions of the global model display substantial mesoscale error growth, due principally to the effect of larger scales. The uncertainties possessing largest spatial scale appear as boundary uncertainties in LAMs, and explain the strong boundary sensitivity and weak local initial data sensitivity observed in many LAMs. We infer that accurate depiction of the largest spatial scales is a first order priority for accurate local prediction, and that for the advective portion of the dynamics, errors of the outer model that provides lateral boundary conditions may impose the largest current practical limitation for many LAM predictions.With 10 Figures     

Turbulent fluxes over inhomogeneous landscape

Mesoscale surface turbulent fluxes over a complex terrain surrounded by oceans have been investigated using a 3-D numerical mesoscale model, under conditions with and without synoptic flows. The study indicated that under synoptically calm condition, the allocation and intensity of mesoscale surface turbulent fluxes (MSTFs) were greatly impacted by the thermally forced mesoscale circulation (TFMC) over mesoscale heterogeneous landscape. The max-imum values of sensible (Hs) and latent (LE) heat fluxes were located over the convergent zones and considerably im-pacted by the soil wetness (M), but did not depend strongly on the atmospheric background thermal stability (β0). The simulated results suggested that the sensible heat flux was closely proportional to the square of wind speed in the surface layer. By the action of synoptic flow, the allocation of LE was shifted to downwind, its intensity increased.     

On the evolution of finite-amplitude disturbance to the barotropic and baroclinic quasigeostrophic flows

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东亚地区沙尘气溶胶影响硫酸盐形成的模式评估

利用STEM-II三维区域大气化学模式,耦合沙尘气溶胶表面相过程,研究了1994年3月1日至14日间东亚地区沙尘气溶胶对硫酸盐形成的影响。结果表明,SO2气体在沙尘气溶胶表面上进行的非均相氧化过程是硫酸盐形成的一条重要途径,由这条途径提供的硫酸盐占其总浓度的20%～50%。 并发现在模拟时段,沙尘暴过程主要影响沙尘源地下游的中国东部地区硫酸盐的分布,使得那里的硫酸盐浓度增加60%以上。     

基于GIS的安徽省重大农业气象灾害测评系统

以安徽省重大农业气象灾害的气候规律分析及遥感监测方法的基础,利用地理信息系统技术,设计并建立了省级农业气象灾害测评系统。该系统运用结构化设计原理,根据用户需求及系统建设的基本目标,确定了系统结构及主要功能,以为主要支撑软件,建立了安徽省干旱,洪涝及低温冷害的基本数据库、灾害监测评估模型和应急反应及决策服务系统。     

全球稻谷主产国遥感估产可行性研究

利用NOAA气象卫星的序列资料,对全球稻谷遥感估产的可行性进行了探讨。并以泰国、美国、越南为例,分别对NDVI植被指数与产量进行相关分析,取得良好的应用效果。此外,还应用数理统计方法对全球稻谷的历史产量进行数学模拟,达到较高的拟合精度。