北京地面气温可预报性及缺测资料恢复的研究

利用１９５１－１９９０年期间北京地面气温资料作未来气温预测可预报性及缺测气温资料恢复的研究，对单月序列使用自回归、选阶自回归、逐步回归和预测残差最小逐步回归及对多月序列使用后两种模型等６种方案进行试验。结果表明，多月序列使用残差最小逐步回归模型有最好的可预报性，且预报方程具有较高的稳定性。本文使用该方案还对１８４１－１９５０年期间的缺测气温资料进行恢复。     

夏季降水量与气温资料的恢复试验

该文对我国汛期降水量和气温缺测资料及资料均一性恢复的方法进行试验研究。对单个气候地区（东北区），以及全国6个气候地区用逐步回归和逐步判别方法进行缺测1～5年恢复试验。对东北地区内所有站点的试验表明，逐步判别分析方法比逐步回归分析方法恢复效果好些；选择邻站用判别分析方法建立的恢复模型，效果更好。全国气候地区试验表明，选择邻站的判别分析方法有较好的恢复效果。     

上海地区最高气温资料的恢复试验

对上海最高气温1924～2001年期间的缺测资料进行了恢复试验,以期通过该个例的研究,探讨我国台站历史资料集中缺测或中断序列的恢复、插补的一般方法.选取使用上海气象观测站的相邻若干台站的最高气温资料,分别用回归分析法、判别分析法和偏最小二乘法,对上海站相应期间缺测资料进行逐年逐月的恢复,并利用交叉检验的均方误差作为恢复效果的评判.结果发现对缺测资料恢复的总效果以偏最小二乘法为最好,因此选用该方法作为资料恢复的主要方法.恢复过程为每次仅恢复某月份、某测站、某年份的缺测资料,恢复后的估计值作为观测值使用,再进行其它缺测资料恢复的新资料集,如此反复地进行,以近期资料开始,逐步向前期资料延拓.这样做的目的是为了使得和后续的观测资料直接连接.     

用逐步回归方法建立前汛期降水量的预报方程

根据新会1971～2003年降水、气温、日照资料，利用相关分析方法挑选因子，然后用逐步回归方法对因子进行筛选，去除次要的，保留最主要的因子，从而建立新会前汛期降水量预报方程。     

中国近50a气候变化复杂性分析

分析了我国气温和降水量变化的兰帕尔－齐夫复杂度空间分布特征，结果表明，平均而言，我国平均气温和降水量变化的复杂度约为10－11，小于随机序列的复杂度13，年平衡气温变化序列的复杂度最小，秋季平均气温变化序列的复杂度最大，季节和年平均气温序列的复杂度小于月平均气温变化序列的复杂度，月总降水量变化序列的复杂度为西部，北部大于南部和东部，我国东南沿海地区气候要素变化的复杂度最大。     

利用车贝雪夫多项式进行资料缺测插补的研究

使用一维车贝雪夫多项式展开进行历史年降水量和月平均气温各种缺测情况下资料的插补试验，在迭代计算过程中，还对理想初值的两种临界迭代次数选取方案和迭代终值法进行了大量的试验。结果表明，一般情况下迭代终值计算精度较高，旱涝年则理想初值拟合结果更好一些；一年缺测插补精度高于连续多年缺测；双向插补计算结果优于单独使用顺序或逆序插补结果。     

基于PC-CCA方法的气象场资料插补试验

引入主成分典型相关分析（ＰＣ－ＣＣＡ）方法建立缺测气象要素场序列的插补模式,对区域性气象场序列（以长江流域月气温距平场为例）各种时空缺测分布型态作插补试验。结果表明,当插补场站网分布型取包含子场在内的混合站网时,建模样本量达２５年就可有最优插补精度,且性能稳定,效果优良。尤其当距平符号单一且大尺度分量占优势时,插补精度随缺测场变化很小     

气候资料缺测插补方法的对比研究

采用均生函数正交筛选（ＭＧＦ）和一维车贝雪夫多项式展开（ＣＰ）进行了年降水量各种缺测情况下资料的插补试验，并计算各种统计量，结果表明：无论何种缺测ＭＧＦ法拟合或插补精度一般高于ＣＰ法，尤其对连续多年缺测和序列一开始便连续缺测更为明显；同一种方法１ａ缺测拟会精度高于多年缺测，连续４—５ａ缺测但在序列中处于不同的位置拟合结果差别不大，但多段同时缺测拟合精度低于一段缺测.     

海南省4～6月降水类型及其年际变化

1前言本文用主分量分析法作海南省18个测站1954～1990年4～6月降水类型及其年际变化的分析。资料取自《广东省地面气象年鉴》、《广东地面气候资料》和《中国降水资料》。个别缺测资料用比值法、Wild法或直线回归方程作订正和延长。2海南省4～6月降水的统计分析从图正可见，等降水量线呈由中部向沿海递减的趋势。琼中、保亭为最大降水量中心，降水量达600mm；定安地区也有一降水量大值中心。最小降水量区出现在西南部沿海的干旱区，其降水量在30Omm以下。根据降水量分布和表1可知，海南4～6月降水变率比较大，最大变率中心出现在白沙、万宁…     

铜川市月气候预测方法

通过统计铜川单站53a历史气候,用Spss11.5对铜川站历史各项气象要素与各月平均气温、降水量进行相关性分析,找出前期各气象要素与预报月的降水、气温相关性好的因子,用逐步回归方法进行模拟,得出铜川站的月平均降水、气温预报模型,用可视化语言Visual Basic 6.0程序设计中的Adodc数据库技术方法,分别建立了铜川站的月降水、平均气温预测因子数据库,63个相关性较好的因子进入模型,实现自动预测,并以Datagrib表格显示预测结果和预测因子组合。从近三年预测结果看,降水距平百分率在20%以内的准确率为30.6%;气温预报误差在1℃以内的准确率为50.0%。需要在实际业务中进一步检验,找出预报和实况的误差关系。     

MDERF产品在贵州月气候预测中的释用

基于MDERF(Monthly Dynamic Extension Range Forecast)模式输出500hPa位势高度场资料和贵州各月干旱综合指数、降水和气温等历史样本,利用秩序回归降尺度法,研究该方法对贵州月干旱综合指数、降水和气温的预报技巧和预测效果.结果表明:该方法从穷尽所有因子组合中选出彼此独立的3个最佳组合因子共同作为预报因子,从而增强可预报性;模型5 a回报试验和2007年8月试报结果表明该方法在实际预测业务中的应用潜力;各气候要素多年的距平相关系数评分比较稳定,其中月干旱综合指数、降水距平百分率、气温距平全年平均距平相关系数评分分别为0.14、0.15和0.14;各气候要素中月气温预报的Pc最高,平均为73%.综合分析表明,该方法在月动力延伸预报产品对贵州月气候要素预测释用中具有较好的应用前景.     

Influence of ENSO and the South Atlantic Ocean on climate predictability over Southeastern South America

We perform a systematic study of the predictability of surface air temperature and precipitation in Southeastern South America (SESA) using ensembles of AGCM simulations, focusing on the role of the South Atlantic and its interaction with the El Niño-Southern Oscillation (ENSO). It is found that the interannual predictability of climate over SESA is strongly tied to ENSO showing high predictability during the seasons and periods when there is ENSO influence. The most robust ENSO signal during the whole period of study (1949–2006) is during spring when warm events tend to increase the precipitation over Southeastern South America. Moreover, the predictability shows large inter-decadal changes: for the period 1949–1977, the surface temperature shows high predictability during late fall and early winter. On the other hand, for the period 1978–2006, the temperature shows (low) predictability only during winter, while the precipitation shows not only high predictability in spring but also in fall. Furthermore, it is found that the Atlantic does not directly affect the climate over SESA. However, the experiments where air–sea coupling is allowed in the south Atlantic suggest that this ocean can act as a moderator of the ENSO influence. During warm ENSO events the ocean off Brazil and Uruguay tends to warm up through changes in the atmospheric heat fluxes, altering the atmospheric anomalies and the predictability of climate over SESA. The main effect of the air–sea coupling is to strengthen the surface temperature anomalies over SESA; changes in precipitation are more subtle. We further found that the thermodynamic coupling can increase or decrease the predictability. For example, the air–sea coupling significantly increases the skill of the model in simulating the surface air temperature anomalies for most seasons during period 1949–1977, but tends to decrease the skill in late fall during period 1978–2006. This decrease in skill during late fall in 1978–2006 is found to be due to a wrong simulation of the remote ENSO signal that is further intensified by the local air–sea coupling in the south Atlantic. Thus, our results suggest that climate models used for seasonal prediction should simulate correctly not only the remote ENSO signal, but also the local air–sea thermodynamic coupling.     

TMI降水结构的反演算法和最佳分辨率选取个例试验

利用热带降雨测量卫星（TRMM）的微波成像仪（TMI）和星载测雨雷达（PR）资料,选取了2003年出现在西北太平洋亚洲季风区的热带气旋ETAU（T0310）,采用间接对数组合方案建立了多频道线性回归算式,对4种不同分辨率（0．1°、0．2°、0．25°、0．5°）进行了TMI反演降水试验。结果表明,间接对数组合法能够较好地表征降水区的范围和强度分布,且反演结果稳定,是由微波亮温资料反演洋面降水的一种较为理想方法。采用0．2°和0．25°分辨率反演降水效果相对较好,具有实际应用价值,能对降水的宏观特征做出一定的指示。本文结果对于利用卫星微波遥感资料反演降水的研究具有一定参考价值。     

STABILITY AND POTENTIAL PREDICTABILITY OF ANNUAL PERCIPITATION OVER CHINA

The precipitation is a primary element which directly affects the agricultural production of thecountry with one fifth of the world population.With the economic development the water resourcestress is getting greater.In this paper,based on the data at 162 stations selected evenly over Chinafrom 1960 to 1991 the stability and potential predictability of annual precipitation have been stud-ied.The eastern and southern parts of the country having abundant precipitation enjoy more stableprecipitation.The north and northwest parts of the country where the precipitations are deficienthave unstable precipitations.The potential predictability approximates to the ratio of the estimatedinterannual variance to the climatic noise.Generally the annual precipitation over China is poten-tially predictable.In the area between the Huanghe River and Changjiang River and the east ofnortheastern China the potential predictability is the lowest in the country.In the north and north-west of the country the potential predictability is greater.The southeastern coast has relatively lowvalues of potential predictability.Also,the method of estimating climatic noise of annual precipita-tion has been discussed from the idea of Yamamoto et al.(1985)in order to estimate the potentialpredictability.     

Hindcast skill and predictability for precipitation and two-meter air temperature anomalies in global circulation models over the Southeast United States

This paper presents an assessment of the seasonal prediction skill of current global circulation models, with a focus on the two-meter air temperature and precipitation over the Southeast United States. The model seasonal hindcasts are analyzed using measures of potential predictability, anomaly correlation, Brier skill score, and Gerrity skill score. The systematic differences in prediction skill of coupled ocean–atmosphere models versus models using prescribed (either observed or predicted) sea surface temperatures (SSTs) are documented. It is found that the predictability and the hindcast skill of the models vary seasonally and spatially. The largest potential predictability (signal-to-noise ratio) of precipitation anywhere in the United States is found in the Southeast in the spring and winter seasons. The maxima in the potential predictability of two-meter air temperature, however, reside outside the Southeast in all seasons. The largest deterministic hindcast skill over the Southeast is found in wintertime precipitation. At the same time, the boreal winter two-meter air temperature hindcasts have the smallest skill. The large wintertime precipitation skill, the lack of corresponding two-meter air temperature hindcast skill, and a lack of precipitation skill in any other season are features common to all three types of models (atmospheric models forced with observed SSTs, atmospheric models forced with predicted SSTs, and coupled ocean–atmosphere models). Atmospheric models with observed SST forcing demonstrate a moderate skill in hindcasting spring-and summertime two-meter air temperature anomalies, whereas coupled models and atmospheric models forced with predicted SSTs lack similar skill. Probabilistic and categorical hindcasts mirror the deterministic findings, i.e., there is very high skill for winter precipitation and none for summer precipitation. When skillful, the models are conservative, such that low-probability hindcasts tend to be overestimates, whereas high-probability hindcasts tend to be underestimates.     

中国区域月平均温度和降水的模式可预报性分析

基于中国台站降水和温度观测资料、中国气象局国家气候中心月动力延伸预报的回算和预测结果讨论了中国区域月平均温度和降水模式可预报性的时空变化特征。文中以持续性预报来表征中国区域月平均温度和降水受外强迫影响下的可预报性,持续性预报技巧存在明显的年际和年代际变化特征;春末夏初和秋季预报评分相对偏低;在中国区域气候变暖和平均降水强度极值增加的背景下,温度的持续性预报评分有明显提高,降水的持续性预报略有下降。月动力延伸预报对月降水和温度的预报能力也存在明显的年际和年代际变化特征;与持续性预报相比,月动力延伸温度预报总体优于持续性预报,降水预报在初春略差,温度预报在8月相对最低。近20余年,月动力延伸预报相对于持续性预报的温度和降水的均方根误差技巧均大于零,其年际变化表现为模式对降水的预测略有提高。两种预报评估结果的空间分布分析表明月动力延伸预报达到显著性水平的正相关区域总体上比持续性预报的范围大,并基本涵盖了持续性预报的高相关区。原因是可预测信息部分来源于外强迫异常的影响,部分来源于对大气内部动力过程的模拟。     

Variability and predictability of Northeast China climate during 1948–2012

In this work, authors examine the variabilities of precipitation and surface air temperature (T2m) in Northeast China during 1948–2012, and their global connection, as well as the predictability. It is noted that both the precipitation and T2m variations in Northeast China are dominated by interannual and higher frequency variations. However, on interdecadal time scales, T2m is shifted significantly from below normal to above normal around 1987/1988. Statistically, the seasonal mean precipitation and T2m are largely driven by local internal atmospheric variability rather than remote forcing. For the precipitation variation, circulation anomalies in the low latitudes play a more important role in spring and summer than in autumn and winter. For T2m variations, the associated sea surface pressure (SLP) and 850-hPa wind (uv850) anomalies are similar for all seasons in high latitudes with significantly negative correlations for SLP and westerly wind anomaly for uv850, suggesting that a strong zonal circulation in the high latitudes favors warming in Northeast China. The predictability of precipitation and T2m in Northeast China is assessed by using the Atmospheric Model Inter-comparison Project type experiments which are forced by observed sea surface temperature (SST) and time-evolving greenhouse gas (GHG) concentrations. Results suggest that T2m has slightly higher predictability than precipitation in Northeast China. To some extent, the model simulates the interdecadal shift of T2m around 1987/1988, implying a possible connection between SST (and/or GHG forcing) and surface air temperature variation in Northeast China on interdecadal time scales. Nevertheless, the precipitation and T2m variations are mainly determined by the unpredictable components which are caused by the atmospheric internal dynamic processes, suggesting low predictability for the climate variation in Northeast China.