重建动力系统方法制作月降水量预报的试验

利用时间滞后延拓相空间的方法，将南京地区一维月降水量资料序列拓展成高维相空间，计算得到降水系统的分维数为３．６，表明该系统是一混沌系统，其自由度最小取４。在具有二次非线性项的假设下求解设定的动力系统程数，建立降水预报方程。预报检验结果表明，利用该方法作局地降水气候预报具有一定的准确度。     

基于多变量相空间重构的局部降水预报

在已有的研究基础上,运用混沌理论中重建动力系统的方法来进行局地降水预测的研究。首先,通过分析降水时序关联维与嵌入相空间轨道的变化规律,探讨该降水时序的混沌动力学特性;接着对月降水量和气温时序进行多变量重构相空间,在相空间内搜索预报向量的k个最优近邻;最后,通过线性回归模型建立相似预报模型,试验结果与实际值吻合较好,证明了方法的有效性。     

咸阳市分县分级降水概率预报方法

通过用大量的经验因子和数值产品相结合,采取预测法、相关法、关联法对预报因子进行多层筛选,既考虑了降水事件发生的有利因素和不利因素,又考虑了降水事件的自身规律性,应用动态预报模型,建立分县降水概率预报方法。     

短期集合预报中定量降水预报集合方法初探

针对短期集合预报中集合平均等方法对极端天气事件预报能力低下的缺陷，提出一种定量降水预报集合方法，简称两步法。该方法首先采用逐级归并法确定集合成员的总体相似度，进而确定集合成员预报场的延伸半径，对各成员的预报场进行修正，然后根据每个成员与其他成员的相似程度，确定各成员的权重系数。这个方法既考虑了集合成员总体的差异性又考虑了降水的概率分布。试验证明，通过上述两步得到的定量降水预报，对提高极端天气事件的预报确率有一定效果。本方法无需历史资料，能很好适应集合成员的改变，实现方便快捷。     

哲盟火灾的气象条件分析及火险预报

文章在分析哲盟火灾与气象条件关系的基础上，建立了火险等级预报方法。该方法既考虑了影响可燃物干燥程度的前期气象要素，特别是无明显降水的持续情况，又考虑了预报日的气象要素，收效较为明显。     

雅安市降水“精细化”预报的动力学基础

雅安市位于四川盆地西缘、青藏高原东麓．兼有“迎风坡”和“喇叭口”的地形特点，降水特多．有“天漏”之称．因此，降水预报在当地显得尤为重要。随着社会的需求．降水预报朝“精细化”发展，是必然的趋势。本文基于“雅安天漏”研究等方面的结果，给出了考虑了系统性降水、热力降水和地形雨的降雨量计算公式。并利用该公式做了“精细化”降水预报方面的尝试。     

资水中下游气象水文预报

以气象要素为依据,以精细化数值天气预报为基础,综合水文预报方法,对资水中下游汛期进行气象水文预报.该方法既考虑了地面积水和降水后的可能来水,又考虑了预报时段内的降水影响,较常规水文预报有更好的使用价值.     

长江中下游旱涝中期预报方法及其业务应用

介绍了双层多因子综合相似的长江中下游旱涝中期预报模型。该模型引入了具有明确动力学和热力学意义的地转西风动量经向输送和经向温度梯度诊断量，同时强调了西太平洋副热带高压对长江中下游夏季降水的关键作用，并考虑了对流层中、低层500hPa高度和850hPa温度的大尺度环流背景场。与过去业务应用的单层相似预报模型相比较，不仅物理意义和天气学含义明确，而且更符合对具有复杂动力和热力机制的降水预报的考虑。5年的预报试验和业务应用结果表明，该方法对长江中下游地区旱涝的中期趋势预报有较好的预报能力。     

湖北省月雨量的相空间投影预报法

考虑到气候系统的非线性特性及有关变量之间的物理关系，应用相空间投影技术来制作月雨量预报。试验表明：该技术对月雨量距平百分率预报的符号相关准确率可达63．8％，对目前的日常长期预报有一定的参考意义。     

集合预报产品释用方法的研究

提出一种动力与统计相结合的集合预报产品的动力统计释用方法，该方法从大尺度大气动力学方程组出发，考虑中期旬尺度的大气环流特征，采用简单的斜压模式，推导出旬降水距平百分率与旬环流形势场的关系，从而建立了旬降水距平百分率预报方程，与相当正压的月降水距平百分率预报方程相比，更符合常规天气预报业务中对实际大气的动力学和天气学意义的考虑，试报结果表明，动力与统计相结合的方法对旬尺度动力延伸集合预报产品的释用具有明显的效果。     

A—B hybrid equation method of nonlinear bifurcation in wave—flow interaction

In this paper, A-B hybrid equation method is given. This method is different not only from high truncated spec-tral method, but also from amplitude evolution method. Dynamic problem in the baroclinic atmosphere may be transferred into complex Lorenz system by means of the method. Therefore, this method is an effective tool for stud-ying nonlinear bifurcation in wave-flow interaction. Meanwhile, it is of advantage to use this method, because it can overcome a lot of difficulties existing in high truncated spectral method and amplitude evolution method.     

基于空间回归的B样条拟合在地面气温资料质量控制中的应用

将B样条拟合算法引入到地面气温资料的质量控制当中,在分析地面气温资料空间相关性的基础上,提出一种基于空间回归的B样条拟合地面气温资料质量控制方法(SRT_BSF方法)。为了检验SRT_BSF方法的有效性及适应性,利用SRT_BSF方法对多个场景地面气温资料进行质量控制,并与反距离加权方法(IDW方法)和空间回归方法(SRT方法)进行比较分析。试验结果表明,SRT_BSF方法相对于IDW方法和SRT方法更能有效地标记出地面气温资料中的存疑数据,同时多组独立案例的分析结果说明SRT_BSF方法具有更好的稳定性和适用性。      

结合中尺度模式物理约束的雷达回波临近外推预报方法研究

研究设计了一种结合中尺度模式物理约束的雷达回波临近智能外推预报方法,该方法在外推预报时效(0—2 h)内即利用中尺度高分辨率模式信息对外推进行约束.首先将模式风场和雷达回波轨迹风场融合成融合风场,然后利用融合风场光流外推形成动力约束外推;并在此基础上利用模式诊断产品和雷达历史资料通过投票回归器集成多种深度学习算法构建回...     

基于微波辐射计和气溶胶激光雷达的边界层高度研究及应用

分别基于微波辐射计温湿度廓线资料的气块法、位温法和比湿法,地面气象资料的罗氏法及气溶胶激光雷达数据的梯度法,计算得出广州地区大气边界层高度,对比分析5种边界层高度结果及其与气象条件、空气质量之间的关系,结合典型大气污染过程分析边界层高度对PM_2.5、O₃浓度的影响。结果显示:（1）利用位温法、气块法、罗氏法、比湿法和梯度法计算得出广州地区平均边界层高度分别为2 207 m、1 239 m、901 m、717 m和660 m,位温法显著高估了广州地区的边界层高度;（2）利用气块法得出的混合层高度日变化能够较好地表征白天大气边界层演变特征,利用气块法和比湿法得出的白天混合层高度与近地面O₃浓度有显著的正相关关系,相关系数在0.5以上,在O₃污染防治中,应同时考虑边界层内垂直输送的影响;（3）利用梯度法得出的边界层高度在污染天气时与PM_2.5浓度的相关性较好,能较好地表现出大气污染情况,在PM_2.5污染天气过程分析中具有较好的应用价值。      

陆地生态系统温室气体排放（吸收）测量方法简评

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Applicability and improvement of different evapotranspiration methods of reference crops in Jiangxi Province

To achieve accurate evaluation of evapotranspiration of reference crops (ET0) in Jiangxi, China, in the absence of systematic climatological data, with reference to the FAO-56 Penman–Monteith (P-M) equation, the Priestley-Taylor (P–T) method, the Makkink method, the Hargreaves-Samani (H–S) method, the Irmak-Allen (I-A) method, the Penman1948 (48PM) method, the Penman-Van Bavel (PVB) method, the Baier-Robertson (B-R) method, the improved Baier-Robertson (M-B-R) method, the Schendel (Sch) method, the Turc method, the Jensen-Haise (J-H) method, and the Brutsaert-Stricker (B-S) method were used to evaluate the daily climatological data collected by 26 weather stations in Jiangxi, China, and 17 weather stations in adjacent provinces. The results were compared with each other and parameter rate determination was conducted. The results indicated that the Turc method exhibited optimized applicability before parameter rate determination and the average root mean square error (R_MSE) and the average normalized root mean square error (N_RMSE) by this method were 0.39 mm/d and 0.157 mm, respectively. However, parameter rate determination led to negligible improvement in accuracy for this method. The Turc method could be directly applied in Jiangxi (except Nanchang). For special distribution of error after parameter rate determination, all methods exhibited significant errors in Northern Jiangxi. Herein, the 48PM method and the B-S method showed good applicability after parameter rate determination and R_MSE and N_RMSE of data by these methods ranged in 0.06 ~ 0.34 mm/d and 0.08 ~ 0.27, 8 ~ 27%, respectively, and their d-indices were close to 1. The annual over-estimations in weather stations in Jiangxi were below 30 mm. In the absence of data about relative humidity and wind speed, the P–T method was an appropriate simplified method for Jiangxi. In this case, α was slightly lower than the default value (1.05 ~ 1.18), R_MSE was within 0.21 ~ 0.66 mm/d, and N_RMSE was within 0.08 ~ 0.308 ~ 30%. Accuracy of R_MSE, d-index, and N_RMSE of data by the P–T method, the I-A method, and the PVB method was consistent with all stations, while that by the Mak method was slightly lower, which could be attributed to severe over-estimation in July and August. R_MSE of the H–S method, the B-R method, the M-B-R method, the J-H method, and the Sch method were above 0.75 mm/d and these methods were not suitable for accurate evaluation of ET0 in Jiangxi, China. The annual ET0 was calculated by various methods (except the 48PM method and the B-S method) exhibited significant variation around 2003. This may be attributed to significant changes in certain meteorological factors over recent years.

     

改进晴空辐射精度的一种处理方法

本文提出在HIRS/2视场中部分有云情况下,由一组相邻视场测值反演晴空辐射的一种方法,并用数值模拟试验对这种方法的精度与Aoki的Q8方法进行了比较,其精度比Aoki的Q8方法有相当大的提高。     

Testing of the bandpass eddy covariance method for a long-term measurement of water vapour flux over a forest

The bandpass eddy covariance method has been used to measure the turbulent flux of scalar quantities using a slow-responsescalar sensor. The method issimilar in principle to the traditional eddy correlation method but includes the estimation of high-frequency components of the flux on the basis of cospectral similarity in the atmospheric surface layer. In order to investigate the performance of the method, measurements of the water vapour flux over a forest with the bandpass eddy covariance method and the direct eddy correlation method were compared. The flux obtained by the bandpass eddy covariance method agreed with that by the eddy correlation method within ±20% for most cases, in spite of a rather slow sensor-response of the adopted hygrometer. This result supports its relevance to a long-term continuous operation, since a stable, low-maintenance,general-purpose sensor canbe utilized for scalar quantities. Oneweak point of the method isits difficulty in principle to measure the correct flux when the magnitude of the sensible heat flux is very small, because the method uses the sensible heat flux as a standard reference for the prediction of undetectable high-frequency components of the scalar flux. An advanced method is then presented to increase its robustness. In the new method, output signals from a slow-response sensor are corrected using empirical frequency-responsefunctions for the sensor,thereby extending the width of the bandpass frequency region where components of the flux are directly measured (not predicted). The advanced method produced correct fluxes for all cases including the cases of small sensible heat flux. The advanced bandpass eddy covariance method is thus appropriate for along-term measurement of the scalar fluxes.     

生态承载力评估方法研究进展

在人类活动越来越多的影响可持续发展的背景下,生态承载力的研究受到了越来越多的关注。本文总结了生态承载力概念演变,介绍了生态承载力主要研究方法:初级生产力法(NPP)、生态足迹法、能值生态足迹法、基于生态系统服务的方法、碳氧平衡法、状态空间法、综合评价法与模型法,并对其优缺点分别进行评述;最后对当前生态承载力研究的不足和未来可能的发展方向进行了综述。     

大气廓线统计反演方法的改进

目前,在由TOVS资料反演大气温度和水汽廓线的业务处理中,使用统计方法。本文探讨了改进现行统计反演方法的途径,并通过数值模拟试验证明,改进的方法与现业务方法相比,反演精度可以有相当犬的改进。