贺兰山树轮晚材宽度记录中的降水量变化

通过贺兰山地区树木年轮晚材宽度的研究，建立了贺兰山地区最近250年来的树轮晚材宽度年表。与气象观测记录的相关分析结果表明，树木生长与生长季当年5—7月降水量呈明显的正响应，在此年表的基础上重建了贺兰山地区过去250年来5—7月降水量，发现其具有明显的干湿变化，相对干旱年占总年数的52％，相对湿润年占总年数的35．5％，平年为14．5％，旱灾是该地区主要旱涝灾害。谱分析结果显示该地区5—7月降水有明显的2．6、3．5、21．3年的3个准周期。同时贺兰山地区降水量的变化历史可以反映东亚夏季风的变迁历史。     

基于TRMM卫星资料的渤海降水遥感估算研究

降水是全球能量平衡和水分循环中的关键要素,但海洋区域实时、准确的降水观测资料难以获取,因此,遥感卫星资料在海洋降水及全球能量和水分循环研究领域具有十分重要的应用前景。本文基于1998~2012年6个气象站点(岛屿或海岸带)的实测降水资料,评估TRMM(Tropical Rainfall Measuring Mission)V7版本3B42、3B43两个降水产品对渤海降水量的估算精度,在此基础上,分析并揭示渤海区域年、季和月降水量的时空特征。结果表明:在日尺度,3B42产品对渤海降水量的估算效果总体较差,而在月、年尺度,3B42、3B43产品与实测降水量比较接近,而且,3B43产品的估算精度稍高;总体上,TRMM表现出低估降水的特点,且当实测月降水量大于300 mm时,这种特征尤为显著;1998~2012年,渤海年降水量表现出明显的年际丰枯变化特征,多年均值为631.6 mm;夏季降水量占年降水总量的62.0%,7月是降水量最丰富的月份;空间上,渤海中南部降水量相对较高,而近岸区域降水量相对较低;受大气环流等因素的影响,夏季降水量重心向西北方向偏移,冬季则向东南方向偏移。     

贺兰山过去196年降水的树轮宽度重建及降水变率

贺兰山属于中国北方的半干旱地区,位于东亚夏季风的西北缘。应用贺兰山南段、中段和北段的3组树轮宽度差值年表合成贺兰山树轮宽度年表,应用邻近采样点的贺兰山东坡、山顶和西坡的气象站资料合成贺兰山气象数据。通过贺兰山树轮宽度年表和贺兰山气象数据的线性回归分析,重建了1802—1997年2—7月降水标准化序列,重建方程的方差解释量是46%。计算重建序列的11年滑动平均标准差后,发现存在着3次标准差的突然变化:1908年标准差由前年的0.38增加到当年的0.56,1942年标准差由两年前的0.57增加到当年的0.70,1956年标准差由前年的0.74降低到当年的0.63。小波分析表明,1908年到1949年之间存在显著的11年准周期,1942年出现2年准周期,该2年准周期到1959年彻底消失。1965—1997年,存在由8年向3年过渡的准周期。11年周期对应着太阳活动周期,2年周期对应“准两年脉动”,8年到3年周期与ENSO周期比较一致。故此认为,当太阳活动、“准两年脉动”或ENSO活动增强时,贺兰山地区降水变率一般比较大,年际间降水变得不稳定。     

陕西黄龙树轮年表的建立及其2-3月降水记录

通过两组油松树轮宽度的研究,建立了陕西黄龙地区过去近200 a来的树轮STD、RES、ARS年表,树轮宽度在20世纪20年代有过明显的下降,1929年前后达到年轮宽度最低值,与历史记载的自民国11年以来连续干旱时期相吻合(1922-1932年).经过相关函数、响应函数分析,发现树轮宽度与生长季当年2-3月降水显著正相关,在此基础上设计了转换方程,重建了过去200 年来黄龙地区早春2-3月降水历史,重建序列的解释方差为44.3%(F=16.298,p<0.001).功率谱分析检测到2-3月降水存在7.69、6.90、6.06、5.13、5.00、4.88、4.65、2.02、2.00 年的周期.     

95年来青岛气候变化的分析

根据１８９８—１９９２年青岛年平均温度和降水资料，分析了青岛９５年来的气候变化，指出年平均气温有明显变暖趋势，而降水量变化不显著。分析了年平均温度和降水的气候阶段，还采用信噪比方法检验了９５年来青岛气候突变。利用谱分析方法分析了气温和降水的主要周期。这些结果与北半球和我国近百年的气候变化趋势基本一致。     

红海榄人工幼苗生长特征研究

幼苗期是红海榄种群占据新环境的关键阶段。在北海潮滩对红海榄的人工高密度海上育苗试验显示,1年生红海榄苗生长节律是平均高生长速度为3.7cm.月1,速生期7—10月平均温度27.1℃,生长速度6.75cm.月1;慢生期为12月至次年3月,平均温度16.3℃,平均生长速度0.9cm.月1;中速生长期4—6月和11月平均气温24.7℃,生长速度3.76cm.月1。3年生苗的生长规律表现为第1年高生长增加最快,第2年全株生物量比第一年增加1.4倍,第3年的生长速度较前两年有所减缓,生物量比第2年增加24%。     

淄博60a气温和降水量变化趋势分析

利用1954—2013年淄博观测站平均气温和降水量资料,运用线性拟合、滑动t检验、Mann-Kendall突变检验和小波分析等方法,对气温和降水量的变化特征进行分析。结果表明:年季平均气温均呈上升趋势,其中冬季增暖最明显,年平均气温在1987年发生增温突变。降水量较气温变化复杂,没有明显突变点,总体呈减少趋势,季节变化差异大,表现为春季降水量明显增加,秋季减少。年平均气温主要存在30a和8a左右周期性变化,年降水量主要存在11a和3a左右周期性变化。     

北印度洋季风区海温与中国北方降水

由1958—1977年北印度洋季风区海温资料和华北7个站平均月降水量资料的功率谱、凝聚谱、位相谱分析,并对资料的距平值作7个月周期的带通滤波后发现,1月份(或8月份)北印度洋季风区海温与中国北方(指华北地区)降水有较高的凝聚值和较好的反位相相关,为准半年的振荡关系。     

京津冀地区暖季降水日变化特征分析

使用2007—2017年京津冀地区156个气象站暖季(5—9月)逐小时降水观测数据,根据地形将研究区域分为6个分区,分析各分区降水量季节内变化和日变化特征,结果表明:1)京津冀的多雨区主要位于沿燕山南麓到太行山,存在多个降雨中心。2)各分区降水量季节内特征总体表现为单峰型,即7月降水量最大,7月第3候至8月第4候是主汛期,8月降水量次之,5月最少。3)降水呈夜间多,白天少的特点,7月初之前的前汛期降水多发生在16—21时;主汛期降水呈双峰型,峰值在17—22时,次峰值出现在00—07时; 8月中旬以后的后汛期多夜间降水,峰值多出现在00—08时。4)高原山区多短历时降水,长历时累计降水对季节降水贡献率大值区位于平原地区,而持续性降水贡献率大值位于太行山区和燕山迎风坡的西部。     

广东沿海表层海温的统计分析

根据闸坡、云澳、硇洲3个海洋站的表层海水温度观测资料，统计了3个站的多年月平均海水温度、极值水温及月平均水温分布规律；通过对月平均温度进行能谱分析，得出水温的变化具有显著的年周期；对旬平均温度进行能谱分析，得出水温变化还具有显著的2a周期和2．8个旬的周期变化。     

A note on nearshore wave features: Implications for wave generation

This paper analyses 10 years of wave data from the Mediterranean Spanish (Catalan) coast considering the mean wave climate and storm events from the standpoint of wind-wave momentum transfer and wave prediction. The data, registered by a buoy at about 12 km from the coastline, revealed two main groups of wave storms, with NW and E directions. NW storms correspond to a fetch-limited situation since the intense wind blows from land. Low-pressure centres located over the Mediterranean Sea produce easterly storms. Near the coast the eastern winds from the sea are replaced by NW winds coming from meteorological patterns over northern Spain and south-western France. Wave storms are classified and studied to obtain their main features (including spectral width, wave length, wave age and bimodality) and discussed in terms of wind-wave momentum transfer for operational wave predictions. Observations show a complex coastal wave climate. Fetch-limited storms presented smaller spectral widths while varying wind situations presented larger widths due to the presence of bimodal spectra. These wave features are highly relevant for wind–ocean momentum transfer and, thus, for current and wave predictions. The spectral width proved to be a good indicator of sea complexity and is thus applicable for improved wind drag estimations. A new drag coefficient formulation is proposed, based on existing wind dependent drag expressions, but including also spectral wave properties (a spectral width parameter) that highlights the characteristics of wind-wave generation under pre-existing swell. Such a formulation, once properly validated with field observations, is expected to improve wind-wave predictions.     

AN INVESTIGATION OF FORECASTING THE CROP YIELD WITH SEA SURFACE TEMPERATURE DATA

In this paper, the relationship between the crop yield in three different regions, the northern part of China, the northeast China and Heilongjiang Province, and the monthly mean sea surface temperature (SST) in the northwest Pacific Ocean is analysed preliminarily; the time and space distribution of the sea areas with high value correlation coefficients (HVCC) between the meteorological crop yield (MY) and the monthly mean SST is given; and crop yields in these regions are simulated by the monthly mean SST. Results obtained show that the stabler relationship between the crop yield in some large regions and the monthly mean SST is presented, so that we can forecast the crop yield in these regions using the monthly mean SST of the sea areas with HVCC.     

Consequences of powerful volcanic eruptions according to dendrochronological data

For the first time we identify the peculiarities of the effect of the most powerful (VEI > 5) volcanic eruptions on the regional climate of the Murmansk region on the basis of Kola Peninsula dendrochronological data for a period of more than 560 years. The analysis was based on the tree-ring chronology covering the period from 1445 to 2005. This chronology was derived from Pinus sylvestris samples collected near the northern tree line at Loparskaya station (68°37′ N; 33°14′ E). The data were processed using modern techniques adopted in dendrochronology (cross dating and standardization). We reveal a significant decrease in the radial tree-ring growth over 8 years (on average) after the eruptions; then its value is restored to the normal level. This finding will help evaluate the response of the regional climate system to external climate forcings in this economically important region for Russia.     

气温的天气和气候记忆性特征分析:以济南和青岛为例

气温的天气和气候记忆性特征分析对于提高气候预测水平具有积极意义。利用济南和青岛1961—2020 年逐日、月和年平均气温资料,运用自相关性函数和标准化频率分布分析了上述时间序列的气温记忆性特征和概率分布特征,并利用结构函数法建立了月、年平均气温距平与日平均气温距平之间的分数阶导数关系。结果表明:(1)济南和青岛的月、年平均气温距平呈现不同程度的记忆性特征,其中年平均气温距平相比于月平均气温距平具有更好的记忆性。(2)济南和青岛的月、年平均气温距平与日平均气温距平之间存在分数阶导数关系,济南和青岛相应的月、年尺度阶数分别为0. 529、0. 665 和0. 553、0. 791,两地的月尺度阶数相近,但青岛略大,青岛的年尺度阶数大于济南,即青岛月和年平均气温距平的记忆性大于济南。(3)济南和青岛的月和年平均气温距平相比于日平均气温距平有不同程度的长尾特征,长尾特征反映了极值温度发生的概率。     

福建春季(3～4月)降水异常的特征分析

本文取全省25个代表站1960－1999年3－4月的降水资料和北半球500hPa高度资料、北太平洋海温的月平均资料为素材，首先标定降水的异常指数和异常年例，其次应用小波分析、自相关、功率谱和周期分析等方法揭示降水的演变规律，最后分析异常降水的500hPa环流背景和海温特征，所得结果可为我省春季降水的短期气候预测提供线索。     

常数和变化积雪密度方案诊断计算积雪厚度的敏感性研究

海冰上积雪的分布是影响海冰与大气能量交换以及气候变化的重要因素。当前的CMIP6气候模式（如CESM2和NESM3）采用定常的积雪密度,而专注于模拟雪厚度和密度变化的模式（如SnowModel-LG）则采用经验的变化雪密度公式。对比CryoSat-2卫星观测的积雪厚度发现,从积雪厚度的空间分布与平均值难以判断出变化雪密度对北冰洋积雪厚度模拟产生何种影响,对于变化雪密度模拟积雪厚度的改进及机制有待进一步研究。本文采用随气温、风速等因子变化的雪密度经验公式模型,并利用SNOTEL单站的长时间序列观测资料,对不同影响因子设计如下敏感性实验:A. 考虑所有气象因子的变化雪密度模型;B. 常数雪密度模型;C. 在A中不考虑风对密实化的影响;D. 在A中不考虑气温对密实化的影响。实验A、B、C和D诊断计算的2018年11月1日至2019年5月10日积雪厚度的均方根误差分别为4.2 cm、4.8 cm、25.9 cm和4.2 cm。结果表明,变化雪密度方案A模拟的积雪密度、厚度在平均值上与常数雪密度的结果接近,但其模拟的积雪厚度均方根误差最小,并且能够模拟出积雪厚度在几天到十几天时间尺度上的高频变化,同时减小了这种高频变化对应时段雪厚模拟结果的相对误差,二者具有一定的相关性。此外,还发现气温变化对积雪密实化的影响远小于风。     

Temporal and spatial variability of precipitation in Sweden and its link with the large‐scale atmospheric circulation

The main characteristics of spatial and temporal variability of the precipitation regime in Sweden were studied by using the long‐term monthly precipitation amount (1890‐1990) at 33 stations. The data were filtered by using Empirical Orthogonal Function (EOF) analysis, which provides principal modes of both spatial variability and time coefficient series describing the dominant temporal variability. Canonical correlation analysis (CCA) was used to reveal association between the atmospheric circulation and the characteristics of the climate variability. Statistically significant upward shifts in the mean precipitation have been found during cold months (March, September, November and December) and only a downward shift (less significant) for August. Simultaneous changes in the time series associated to the optimally correlated circulation patterns were found, indicating an important role of the circulation. The circulation patterns are given by the North Atlantic Oscillation (NAO) in March and December and a cyclonic structure centred over southern Scandinavia in September and November. These changes may have induced changes in the mean precipitation seasonality reflected by a shift of the maximum precipitation from August to July (after 1931 for western part and after 1961 for the southeastern coast) and after 1961 to September, October or November for other regions. Combining rotated EOF analysis with cluster analysis, 4 regions with similar climate variability were objectively identified. For these regions the standardised monthly precipitation anomalies were computed. The frequency of the extreme events (very dry/wet and dry/wet months) over 5‐year consecutive intervals was analysed. It has been concluded that extreme wet months were more frequent than extreme dry months over the entire country, especially in the northern and southeastern part.     

Homogenization and trend analysis of 1960–2015 in situ sea surface temperature observations along the coast of China

Sea surface temperature(SST) measurements from 26 coastal hydrological stations of China during 1960–2015 were homogenized and analyzed in this study. The homogenous surface air temperature(SAT) series from meteorological stations which were highly correlated to SST series was used to construct the reference series.Monthly mean SST series were then derived and subjected to a statistical homogeneity test, called penalized maximal t test. Homogenized monthly mean SST series were obtained by adjusting all significant change points which were supported by historic metadata information. Results show that the majority of break points are caused by instrument change and station relocation, which accounts for about 61.3% and 24.2% of the total break points,respectively. The regionally averaged annual homogeneous SST series from the 26 stations shows a warming trend(0.19°C per decade). This result is consistent with that based on the homogenized annual mean SAT at the same region(0.22°C per decade), while the regionally averaged mean original SST series from the same stations shows a much weaker warming of 0.09°C per decade for 1960–2015. This finding suggests that the effects of artificial change points on the result of trend analysis are remarkable, and the warming rate from original SST observations since 1960 may be underestimated. Thus a high quality homogenized observation is crucial for robust detection and assessment of regional climate change. Furthermore, the trends of the seasonal mean homogenized SST were also analyzed. This work confirmed that there was an asymmetric seasonal temperature trends in the Chinese coastal water in the past decades, with the largest warming rate occurring in winter. At last,the significant warming in winter and its relationships to the variability of three large-scale atmospheric modes were investigated.     

未来黄淮海地区夏玉米光温水资源适宜度及灾害风险演变特征

为探索未来气候变化对黄淮海地区农业气候资源和夏玉米气候适宜度及灾害的影响,以黄淮海地区1981—2021年56个农业气象观测站夏玉米生育期观测资料、84个气象站逐日气象要素观测资料及中尺度区域气候模式（Regional Climate Model Version 3,RegCM3）输出的未来气候情景（Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios A1B,IPCC SRES A1B）下黄淮海2022—2100年0.25°×0.25°共897个格点逐日气象资料为基础,分析未来黄淮海地区光温水等农业气候资源演变特征,建立黄淮海夏玉米生长发育气候适宜度模型及气候适宜度灾害指数模型,研究未来气候变化对黄淮海夏玉米气候适宜度的影响特征,预估夏玉米农业气象灾害发生风险及特点。结果表明：（1）2022—2100年黄淮海地区夏玉米生长季热量资源呈明显增加趋势,降水资源总体为微弱上升趋势且阶段性变化明显,光照资源变化趋势不明显。（2）2022—2100年夏玉米全生育期气候适宜度呈总体平稳略有下降波动趋势,并具有一定阶段特征和发育期差异。各生育期相比,播种出苗期气候适宜度相对最差,成熟期最好。（3）全生育期温度适宜度总体呈稳定波动下降趋势,说明未来气候明显变暖趋势对夏玉米生长总体不利;水分适宜度和光照适宜度总体稳定、变化趋势不明显,说明未来水分和光照资源对夏玉米的生长基本有利。（4）由各年代来看,2080年代、2090年代温度适宜度最差,2020年代最好;2030年代水分适宜度最差,2080年代最好;2080年代、2090年代光照适宜度明显偏差,2020年代、2030年代明显偏好。综合来看,2061—2100年期间夏玉米气候适宜度总体偏差,2020年代最好。（5）抽雄吐丝期遭受高温热害风险最大,三叶至七叶期发生旱涝风险最大,播种出苗期发生寡照（连阴雨）风险最大,而成熟期发生各种农业气象灾害风险均最小。（6）2080—2098年期间夏玉米拔节期、抽雄吐丝期、灌浆至乳熟期遭受高温热害的风险大;2031—2035年、2046—2056年播种出苗至拔节期发生阶段性严重旱涝灾害风险等级高。2030年代和2040年代及2026年、2080—2093年播种出苗期出现寡照（连阴雨）的风险较大。