Interpolation of Daily Global Solar Radiation with Thin Plate Smoothing Splines

Summary Thin plate smoothing splines incorporating topographic dependence were used to interpolate daily global solar radiation in the Bavarian forest ecosystem monitoring network, with the degree of data smoothing determined by minimizing the generalized cross validation. A simple cross validation method was used to discuss the spatial distribution of mean relative errors at 18 forest climate stations. The results show that, from this network 14%–30% mean relative errors can be expected for most of these forest climate stations in summer, and 20%–30% mean relative errors can be found at a few of forest climate stations in winter. Time-averaging can reduce these interpolation errors. In this network a mean relative error of 10% can be expected for weekly and biweekly mean solar radiation at most of forest climate stations in summer. Large errors are related to low radiation amount under heavy cloud cover. Mean relative errors increase as daily global solar radiation decreases. Received April 20, 1999 Revised January 20, 2000     

Accuracy of temperature and precipitation reproduction in Russia with global climate archives

Four climate archives at the regular grid points organized on the basis of interpolation and model reanalysis of observational data are considered. The regional differences between the air temperature and precipitation fields are estimated, the comparison with the observational data at 455 weather stations over the Russian territory and adjacent countries is considered. It is noted that global archives give biased estimates of the monthly and seasonal precipitation amount, annual mean air temperature and temperature sums of the warm and cold seasons. The maps of errors of climate characteristics for each of the archives are calculated and compiled, probable reasons for poor accuracy are analyzed.     

1961—2020年乌鲁木齐市气候舒适度变化[*]

基于乌鲁木齐市及其周边9个气象站1961-2020年气候资料以及综合气候舒适度指数模型,采用统计学方法和ArcGIS的精细化空间插值技术对近60a气候舒适度时空变化进行分析。结果表明,乌鲁木齐市气候舒适度及其变化具有明显的区域性和季节性差异:（1）气候舒适度指数的年内变化,平原地带呈双峰双谷的“M”型,山区为单峰单谷的“∩”型。（2）受气温升高、相对湿度增大、风速减小、日照时数减少的综合影响,近60a平原地带春、秋、冬季气候舒适度指数显著（P=0.05）增大,夏季显著减小;山区夏、秋季气候舒适度指数显著增大,冬、春季变化不明显。（3）近30a（199l-2020年）较前30a(196l-1990年),春季和秋季平原地带气候较舒适区海拔上限升高了100-150m,山区气候较不舒适区和不舒适区向高海拔抬升了50-100m;夏季北部平原气候较舒适区海拔上限升高了100-150m,山前倾斜平原至中山带的气候舒适区向高海拔抬升了约100m,高山带气候较不舒适区和不舒适区也向高海拔抬升并压缩了50-100m;冬季虽气候舒适度指数有所增大,但全市属于气候不舒适区的状况未发生改变。     

Differences between true mean daily, monthly and annual air temperatures and air temperatures calculated with three equations: a case study from three Croatian stations

Differences between true mean daily, monthly and annual air temperatures T0 [Eq. (1)] and temperatures calculated with three different equations [(2), (3) and (4)] (commonly used in climatological practice) were investigated at three main meteorological Croatian stations from 1 January 1999 to 31 December 2011. The stations are situated in the following three climatically distinct areas: (1) Zagreb-Gri? (mild continental climate), (2) Zavi?an (cold mountain climate), and (3) Dubrovnik (hot Mediterranean climate). T1 [Eq. (2)] and T3 [Eq. (4)] mean temperatures are defined by the algorithms based on the weighted means of temperatures measured at irregularly spaced, yet fixed hours. T2 [Eq. (3)] is the mean temperature defined as the average of daily maximum and minimum temperature. The equation as well as the time of observations used introduces a bias into mean temperatures. The largest differences occur for mean daily temperatures. The calculated daily difference value from all three equations and all analysed stations varies from ?3.73 °C to +3.56 °C, from ?1.39 °C to +0.79 °C for monthly differences and from ?0.76 °C to +0.30 °C for annual differences.     

基于DEM的新疆克州气候要素空间分布模拟

摘要: 根据新疆克州及其周边13个气象台站1961-2010年的历史气候资料,采用基于DEM的空间插值技术对该地区年平均气温、降水量和日照时数等气候要素的空间分布进行了模拟分析。结果表明：（1）经验证,该方法对克州年平均气温等主要气候要素的空间分布模拟效果较好,精度较高;（2）新疆克州年平均气温的空间分布总体呈现“平原高,山区低”的特点;年降水量呈现“北部多,南部少;山区多,平原少”的空间分布格局;年日照时数的空间分布总体呈现“高山带多,中、低山带和山前倾斜平原少”的特征。     

Mountain–valley precipitation differences in the northern Alps: an exemplary high-resolution modeling study

This paper investigates the dependence on environmental conditions of altitudinal precipitation differences in the northern Alps, based on high-resolution numerical simulations with the MM5 model for a selected region in the Bavarian Alps (Zugspitze mountain and surrounding valley stations). Three exemplary precipitation events representing climatological regimes with different orographic enhancement characteristics are selected. After validating the MM5 precipitation fields against the available surface observations, the model results are used to analyse the interactions of atmospheric dynamics and cloud microphysics with the local orography. The first two cases (19–22 March 1997, 05–09 February 1999) are characterized by a strong northwesterly or northerly flow, associated with large precipitation differences between the mountain and the surrounding valley stations. For these cases, the model results indicate a dominance of the classical seeder–feeder mechanism, with strong orographic lifting generating dense orographic clouds over each individual mountain ridge, which in turn intensify precipitation. The related surface precipitation maxima can be found near the mountain peaks or somewhat in the lee due to hydrometeor drifting. The third case (05–07 December 1992) represents conditions with relatively small (i.e. below climatological average) precipitation differences between the Zugspitze and the surrounding valley stations. For this event, the model results indicate that relatively weak ambient winds at and below Alpine crest level (700 hPa) were primarily responsible for the lack of substantial precipitation enhancement. Precipitation was nevertheless moderately intense because of strong frontal lifting at higher levels. In all three cases, the agreement between simulated and observed precipitation patterns is so high that there is good reason to expect that mountain–valley precipitation differences will be quantitatively predictable for nonconvective events once a sufficiently high model resolution is computationally affordable.     

Dependence of the agcm climatology on the method of prescribing surface boundary conditions and its climatological implication

By using IAP 9L AGCM, two sets of long-term climatological integration have been per-formed with the two different interpolation procedures for generating the daily surface boundary conditions. One interpolation procedure is the so-called “traditional” scheme, for which the daily surface boundary conditions are obtained by linearly interpolating between the observed monthly mean values, however the observed monthly means cannot be preserved after interpolation. The other one is the “new” scheme, for which the daily surface boundary conditions are obtained by linearly interpolating between the "artificial" monthly mean values which are based on, but are dif-ferent from the observed ones, after interpolating with this new scheme, not only the observed monthly mean values are preserved, the time series of the new generated daily values is also more consistent with the observation. Comparison of the model results shows that the differences of the globally or zonally averaged fields between these two integrations are quite small, and this is due to the compensating effect between the different regions. However, the differences of the two patterns (the global or regional geographical distributions), are quite significant, for example, the magni-tude of the difference in the JJA mean rainfall between these two integrations can exceed 2 mm/day over Asian monsoon regions, and the difference in DJF mean surface air temperature can also exceed 2oC over this region. The fact that the model climatology depends quite strongly on the method of prescribing the daily surface boundary conditions suggests that in order to validate the climate model or to predict the short-term climate anomalies, either the " new* interpolation scheme or the high frequency surface boundary conditions (e.g., daily or weekly data instead of the monthly data) should be introduced. Meanwhile, as for the coupled model, the daily coupling scheme between the different component cli?mate models (e.g., atmospheric and oceanic general circulation models) is preferred in order to partly eliminate the “climate drift” problem which may appear during the course of direct coupling.     

A daily temperature dataset over China and its application in validating a RCM simulation

This paper describes the construction of a 0.5°×0.5°daily temperature dataset for the period of 1961- 2005 over mainland China for the purpose of climate model validation. The dataset is based on the in- terpolation from 751 observing stations in China and comprises 3 variables: daily mean,minimum,and maximum temperature.The"anomaly approach"is applied in the interpolation.The gridded climatology of 1971-2000 is first calculated and then a gridded daily anomaly for 1961-2005 is added to the climatologY to o...     

气候变化对新疆哈密瓜种植气候区划的影响

基于新疆101个气象台站1961-2013年逐日平均气温、最高气温、最低气温和日照时数资料,采用线性趋势分析、累积距平、保证率分析以及ArcGIS空间插值方法,分析影响哈密瓜种植的关键气候因子（日平均气温稳定≥15℃日数、≥20℃光温指数以及6-8月平均气温日较差）时空变化特征,并结合各气候因子突变前、后的变化特征,研究了气候变化对新疆不同熟型哈密瓜最佳种植区、次佳种植区和不宜种植区分布区域及其面积的影响。结果表明：新疆≥15℃日数、≥20℃光温指数、6-8月平均气温日较差的空间分布表现为“南疆多、北疆少,东部多、西部少,平原和盆地多、山区少”的特点。近53年,新疆≥15℃日数以2.493 d/10a的倾向率显著增多（P＜0.001）,≥20℃光温指数以0.06/10a的倾向率显著增大（P＜0.001）,6-8月平均气温日较差以-0.249℃/10a的倾向率显著（P＜0.001）减小,各要素还分别于1997年和1987年发生了突变。新疆哈密瓜种植气候可分为4个大区和7个亚区。受气候变化的影响,1997年后较其之前,新疆中、晚熟哈密瓜最佳种植区明显扩大,次佳种植区有所减小;早熟哈密瓜适宜种植区以及哈密瓜不宜种植区也不同程度地减小。     

典型温带针阔叶混交林碳收支对温度的响应特征

森林生态系统是一个庞大的碳储备系统,在当前气候变暖条件下,温度变化会对森林生态系统的碳收支过程产生重要影响。该文选择长白山温带针阔混交林森林生态系统（CBS）作为研究对象,利用多年通量及小气候观测资料分析该生态系统碳收支过程对温度的响应特征,结果显示该温带森林碳交换的季节变化特征十分明显。生态系统总初级生产力GPP、生态系统呼吸R_e和净生态系统碳交换NEE在2003—2008年的月平均变化显示,碳收支3个组分最大值均出现在夏季,GPP最大值出现在7月,R_e最大值主要出现在8月,NEE负方向的最大值主要出现在6月或7月,表现为碳吸收。在日尺度和月尺度对温度的响应上,GPP和R_e都是随温度（气温和5 cm土壤温度）呈显著的指数升高形式。在日尺度上和月尺度上, NEE对气温的响应皆是分段线性形式,先是随气温的上升而正向增大,表现为碳排放;当超过临界温度,随气温的继续上升而负值增大,表现为碳吸收。根据温度、GPP、R_e以及NEE的季节的变化,每年达到最大的GPP、R_e以及NEE的最适温度均不同,这表明了在气温变化的背景下,生态系统的最适温度也在随之改变,也表明了不考虑其它因素的影响,在气候变暖的背景下,长白山针阔混交林森林生态系统的GPP、R_e随气温的升高增大,而NEE随气温的升高而减小。     

Spatial Interpolation of Daily Precipitation in China: 1951--2005

Climate research relies heavily on good quality instrumental data; for modeling efforts gridded data are needed. So far, relatively little effort has been made to create gridded climate data for China. This is especially true for high-resolution daily data. This work, focuses on identifying an accurate method to produce gridded daily precipitation in China based on the observed data at 753 stations for the period 1951--2005. Five interpolation methods, including ordinary nearest neighbor, local polynomial, radial basis function, inverse distance weighting, and ordinary kriging, have been used and compared. Cross-validation shows that the ordinary kriging based on seasonal semi-variograms gives the best performance, closely followed by the inverse distance weighting with a power of 2. Finally the ordinary kriging is chosen to interpolate the station data to a 18 km×18 km grid system covering the whole country. Precipitation for each 0.5o×0.5o latitude-longitude block is then obtained by averaging the values at the grid nodes within the block. Owing to the higher station density in the eastern part of the country, the interpolation errors are much smaller than those in the west (west of 100oE). Excluding 145 stations in the western region, the daily, monthly, and annual relative mean absolute errors of the interpolation for the remaining 608 stations are 74%, 29%, and 16%, respectively. The interpolated daily precipitation has been made available on the internet for the scientific community.     

基于动态时间规整的气温日值数据二次插补

气温作为研究气候演变最基础的物理量,其日值序列的完整性和准确性对于气候分析与评估工作有着重要意义。近些年随着大量无人值守地面加密自动气象站的布设,不断出现随机站点和随机长度这种双随机特点的气象资料序列缺失,给气候分析和业务应用造成了不小的障碍。针对现有气象数据插补方案的不足,提出了一种全新的基于动态时间规整(dynamic time warping,DTW)的气温日值数据二次插补方法。该方法采用了一种实时的插补策略,主要技术内容包括:1)利用一元线性回归方程将原始气温观测时间序列分解出拟合直线和残差曲线,并将二者重构组成新的气温序列;2)给出了气温插补区的定义和插补条件;3)提出了利用动态时间规整方法计算站点间距离的新模式。利用山东省2021年的气温实况数据对该方法进行了双随机检验,检验结果表明:该方法可以满足日平均气温、日最高气温和日最低气温数据的插补需求;在插补流程中采用DTW距离测度和二次插补的组合方法,其插补效果优于目前常见的基于站点地理临近关系的组合方法;该方法对地形有一定的敏感性,平原或丘陵地区的插补效果要优于山地地区。     

博州近45年气温变化特征分析

用博州4个气象站1960～2004年的月平均气温资料,分析了博州3个气候区域近45a来的气温变化特征.结果表明：45a来博州地区气候逐渐变暖,特剐是上世纪80年代中期以来增温尤为明显,中部博河河谷区及东部平原增温幅度明显大于博州山区.博州山区的夏季气温略有下降.上世纪60年代异常冷冬、凉夏事件最多,80年代异常冷暖事件最少.     

重庆山地区域气象要素空间插值方法对比

利用重庆地区1999年和2018年气象数据, 分别采用薄盘光滑样条、协同克里金、普通克里金、反距离加权4种方法, 从年和月两种尺度对气温、降水、太阳总辐射三个要素进行空间插值; 采取交叉验证方法, 用MAE、MRE、RMSE评估插值精度, 确定各要素最优插值方法。结果表明: 气温和太阳总辐射最优插值方法为薄盘光滑样条, 降水为反距离加权; 插值精度上气温、太阳总辐射高值月份优于低值月份, 降水则相反, 但三个要素均表现出年尺度优于月尺度。MRE检验表明, 插值精度为气温>太阳总辐射>降水, 1999年年尺度插值精度分别为1.86%、4.60%、6.87%, 月尺度插值精度分别为2.79%、5.82%、17.42%;2018年太阳总辐射年、月尺度插值精度分别为3.03%、4.88%, 区域站加密后气温、降水年尺度插值精度分别为2.03%、11.20%, 月尺度对应插值精度分别为3.20%、23.14%。     

柴达木盆地近40a气候变化及其对农业影响的研究

利用柴达木盆地6个代表站逐日平均气温、逐月降水资料以及逐日最低气温资料。对盆地40a来的气候变化特征进行分析。同时分析了气候变化对农业生产的影响。为充分利用变化了的农业气候资源。减少不利因素带来的影响提出了对策和建议。     

大气污染对太行山中部地区地表风的影响

为了研究大气污染对太行山中部地区地表风的影响,我们对阳泉、榆社(高山站),石家庄、邢台(平原站)4个站点1966~2005年间的能见度、近地面温度、近地面风速数据进行了统计计算与趋势分析。结果显示:在平原站能见度相对山坡站下降更加明显的背景下,平原站的近地面温度、近地面风速、850hPa风速都呈下降趋势;而山坡站的近地面温度、近地面风速呈上升趋势。分析表明:(1)由于气溶胶的辐射效应与冷却效应,抑制了垂直通量的上下传输,致使平原站下午的近地面气温呈下降趋势,平原站和高山站的地表风速呈相反的变化趋势。(2)平原站850hPa (与高山站高度相近)风速呈现下降趋势,印证了高山站的近地面风速增加是气溶胶的辐射效应减弱了垂直能量交换造成的。      

A simple method of computing the variation of annual precipitation over mountainous terrain

A method for computing the distribution of annual precipitation for mountainous areas is presented. As a pilot study, the South Thompson River basin in British Columbia is examined. In addition to data from climatological (valley) stations, annual precipitation is estimated for snow course (mountain) locations from the water equivalent of the snowpack on April 1.An equation for the dependence of precipitation amount on orography is derived from simple physical considerations. Regression equations based on this are then computed and the calculated precipitation is checked with runoff data. A basic predictor is the mean vertical water vapor transport through a horizontal unit area due to flow over undulating terrain. This depends on the average slope of a region 3 deg long by 2 deg lat centered on each grid point. The transport at the earth's surface has a simple correlation coefficient with the combined valley and mountain precipitation data of 0.76. When the transport is computed at the mean cloud base (taken as 1800 m above sea-level), the correlation coefficient rises to 0.87.     

西藏冰湖溃决灾害事件极端气候特征

以1960年以来西藏境内已有记载的27次冰湖溃决灾害事件作为研究对象,基于西藏国家气象站点长时间序列（有效记录至今）日气温和日降雨数据,计算得到16个极端气温指数和6个极端降雨指数。通过主成分变换,提取综合极端气温指数和综合极端降雨指数,并进行历史（10年内对比）极端气候特征对比,获得冰湖溃决灾害发生当年及当月极端气候状态,结果表明西藏冰湖溃决灾害发生期（当年及当月）极端气候特征显著,反映极端气候状态对于激发西藏冰湖溃决灾害发生的重要贡献,具体表现为：(1) 67%（18次）的冰湖溃决事件发生当年综合极端气温指数和综合极端降雨指数均大于前期50%年份的综合极端气候指数,其中,13次灾害发生当年极端气候异常水平超过前期70%年份;(2)已有灾害暴发月份记载的25次冰湖溃决事件中,19次冰湖溃决事件发生当月极端气候指数异常偏高,11次冰湖溃决事件发生当月极端气温和极端降水均大于75%往年同期综合极端气候指数;(3)部分灾害事件如扎日错（1981年6月)、龙纠错溃决（2000年8月）等,灾害发生当年极端气温状态低于往年,而暴发当月综合极端气温指数和综合极端降雨指数均大于历史同期水平,表现为加剧状态;(4)所有冰湖溃决灾害发生当月的综合极端气温指数均高于往年同期指数,表明短历时极端气温事件对高原冰湖溃决灾害形成具有重要影响。     

月尺度气温可预报性对资料长度的依赖及可信度

利用全国518个站1960—2011年逐日气温观测资料和160个站1983—2012年月尺度气温客观预测数据,基于非线性局部Lyapunov指数和非线性误差增长理论,研究中国区域月尺度气温可预报性期限对资料序列长度的依赖性。结果表明:气温可预报性期限对资料序列的长度有一定程度的依赖性,在西北、东北及华中地区尤为明显。平均而言,45年的资料序列长度才能够得到稳定合理的可预报性期限。为了验证气温可预报期限计算结果的可信度,将月尺度气温的可预报性期限与客观气候预测方法的预报评分技巧进行对比,发现两者结果非常一致。其中,由观测资料得到的1月气温的可预报性期限明显低于7月,1月客观气候预测方法的预报评分技巧也明显低于7月,且1月 (7月) 预报评分的空间分布型与1月 (7月) 气温可预报性期限的空间分布型较为一致。因此,利用非线性局部Lyapunov指数和台站逐日观测资料分析气温的可预报性期限结果是可信的。     

城市化对长沙市两气象站气温记录的影响

为深入认识城市对其附近气象站气温的影响,采用位于长沙市区东部和西部两个气象观测站的2007-2009年的逐日气温、风向和风速资料,结合地表覆盖特征数据,对比分析了两站气象记录差异,并通过改进的城市影响指数模型估算了气温资料中的城市影响偏差。分析显示：（1）2007-2009年东、西气象站逐月平均气温（T_mean）、最高气温（T_max）和最低气温（T_min）差异很大,最大差异分别可达0.90℃、0.83℃和1.34℃;（2）受城市及风向的影响,两气象站的逐月城市影响指数（K）差异较大,东、西站平均K值分别为2.01和1.50,年内同一台站的K值存在季节变化规律;（3）两站逐月△K与△T之间存在极显著正相关关系;（4）东、西两站2007年T_mean中的城市增温最大,分别达0.63℃和0.45℃。城市附近气象站气温记录受城市规模、风向和风速等因素影响明显,在分析长历时气候变化特征和利用站点记录数据进行空间分析时,有必要对气温数据进行订正。