石羊河流域1960～2009年参考蒸散量与蒸发皿蒸发量变化特征

以石羊河流域5个气象站点1960～2009年逐日气象资料为基础,从估算模型和统计角度计算分析了该流域参考蒸散量及蒸发皿蒸发量的变化趋势和变化原因。结果表明：过去50 a石羊河流域蒸散发呈增加趋势,个别站点达极显著水平（p＜0．01）,1960～2009年和1970～2009年不同时段的选择对分析结果有一定的影响。估算模型理论分析认为桑斯威特法计算的参考蒸散量变率主要由气温决定,蒸发皿蒸发量和彭曼蒙蒂斯公式计算的参考蒸散量变化则是辐射、气温、风速及空气饱和差共同作用的结果,而相关分析和突变检验的分析结果验证了上述结论,并得出过去50 a石羊河流域蒸发皿蒸发量和彭曼蒙蒂斯公式计算的参考蒸散量变化的主要决定因素是空气饱和差。     

安康水库蓄水前后上游气候变化特征

利用陕西省安康水库上游气象站点的月及日降水、气温、蒸发等气候资料,分析了安康水库蓄水前后上游流域气候变化特征。分析结果表明,年降水量呈逐年代减少趋势,年平均温度呈增暖趋势,年蒸散量呈减少趋势;蓄水后年及主汛期降水量、雨日、暴雨日数、极端强降水概率、蒸散量均比蓄水前减少,平均气温比蓄水前升高,其中冬季升温幅度最大;主汛期和年降水量、平均气温蓄水前后差异显著,冬季蒸散量蓄水前后差异显著。近45年来汉江径流量呈下降趋势,降水对径流影响显著。     

1966—2015年天山南北坡空气湿度差异及其影响因素

利用天山地区近50年(1966—2015年)逐日气象资料,采用Mann-Kendall趋势检验法研究了天山南北坡相对湿度(RH)的时空变化特征,分析了天山南北坡RH对平均气温、降水量、平均风速、参考蒸散量、日照时数的敏感性,并探讨了引起RH变化的主导因素。结果表明：(1)整个天山地区RH变化有略微上升的趋势但不显著,北坡RH总体呈下降趋势,南坡RH总体呈上升趋势。(2) RH空间分布呈自北向南递减趋势,南北坡全年及春季以下降趋势为主,而夏、秋、冬三季均以上升趋势为主,且南坡变化趋势的显著性高于北坡。(3) RH对风速、气温、日照时数及参考蒸散量均为负敏感,对降水量为正敏感。北坡RH对各气象因子的敏感程度依次为日照时数>参考蒸散量>风速>气温>降水量,南坡敏感程度依次为日照时数>风速>参考蒸散量>气温>降水量。空间分布上,仅降水量敏感系数高值区位于北坡伊犁河谷,其余要素敏感系数高值区均位于南坡。(4)参考蒸散量是影响天山地区RH变化的主导因子,整个天山地区参考蒸散发贡献率较高,日照时数贡献率高值区集中于北坡伊犁河谷,风速、降水量、气温贡献率高值区均集中于南坡克孜勒苏地区。     

乌鲁木齐河流域参考作物蒸散量时空变化特征

根据乌鲁木齐河流域5个气象站近30a的地面气象观测资料.应用1998年FAO最新推荐的Penman-Monteith公式计算了各月参考作物蒸散量ETo,在此基础上,分析了ETo的月际和年际变化特征,并探讨了各气候要素和海拔高度与ETo的相关关系。结果表明,乌鲁木齐河流域ETo空间变化较大。从山前冲洪积平原的人工绿洲区到高寒地带的乌鲁木齐河源头ETo多年平均值呈明显递减趋势,平均垂直递减率为17.3mm.（100m）-1;30a来,流域各站的年参考作物蒸散量ETo均呈递减趋势,递减速率为-0.05mm.a-1～-5.21mm.a-1;ETo与平均气温、平均最高气温、平均最低气温、空气相对湿度、风速、日照时数、降水量和小型蒸发皿蒸发量均具有较好的相关性;造成近30a乌鲁木齐河流域参考作物蒸散量呈递减趋势的气候原因是：气温、空气相对湿度升高和降水增多以及风速、日照时数减小等气候变化综合作用的结果。     

吉林省参考作物蒸散量的时空变化特征及影响因素

基于吉林省50个气象站1960—2014年逐日最高气温、最低气温、日照时数、风速数据,采用Penman-Monteith算法,计算各站逐日参考作物蒸散量,进而计算各站及全省四季和年平均参考作物蒸散量,利用数理统计方法,结合地理信息系统软件,分析参考作物蒸散量的时空变化特征及主要气候影响因子。结果表明:近55 a,吉林省年平均参考作物蒸散量为876 mm,年参考作物蒸散量呈显著下降趋势(p <0. 01);空间分布差异显著,由东南向西北逐级递增,56%的站点呈显著下降趋势(p <0. 05)。参考作物蒸散量夏季最大、春季次之、冬季最小,且均呈下降趋势,但只有春季的下降趋势显著(p <0. 01);春、夏、秋、冬季与年平均参考作物蒸散量在空间分布上基本一致,但气候倾向率为负值以及通过显著性检验的站点数依次减少。全省四季和年参考作物蒸散量均与降水呈显著负相关,与日照时数、风速、最高气温呈显著正相关;其中年、春、夏、秋季与气温日较差以及春、夏、秋季与平均气温也呈显著正相关;冬季与最低气温、平均气温呈显著正相关;而典型站点参考作物蒸散量各季节影响因素及影响大小略有差异,各气象因子的共同作用导致了参考作物蒸散量的变化。     

1961-2010年青海高原蒸发皿蒸发量变化及其对水资源的影响

利用1961-2010年青海省气象观测资料,分析了青海高原近50年蒸发皿蒸发量的时空分布特征和变化趋势,并采用偏相关及主成分分析法,探讨了青海高原蒸发皿蒸发量变化的气候成因及其对水资源的影响。结果表明：近50 a来青海高原蒸发皿蒸发量呈显著下降趋势,它是热力、水分、动力因子综合作用的结果,在三类因子中,动力及水分因子对蒸发皿蒸发量的影响较大,而热力因子相对较小;区域分析表明,影响东部农业区和柴达木盆地蒸发量的主导因子是平均风速和相对湿度,三江源区为相对湿度,而唐古拉山区为气温日较差。通过分析黄河上游可能蒸散量与地表水资源的关系发现,蒸散量对地表水资源的负效应十分显著,其中夏季蒸散量对于平均流量的影响最为显著,而秋季平均流量对蒸散量的响应最为敏感。     

近10年来黄河上游气候及水资源变化特征分析

利用黄河上游地区13个气象台站1961—2014年气温、降水量及唐乃亥水文站资料,分析了该地区年气温、降水量、蒸散量等气候要素及流量的变化特征。研究表明:2001—2014年黄河上游地区年平均气温持续升高,升温速率明显大于1961—1986年、1987—2000年;年降水量均呈显著增多趋势,年降水量变化的空间分布河曲下游增多趋势明显,年降水量近10年增加速率大于1961—1986年、1987—2000年;蒸散量变化不明显;近10年年流量呈显著增加趋势,增幅大于1961—1986年、1987—2000年,丰水年增加,枯水年减少。     

澄碧河水库上游流域气候变化特征及其影响分析

运用数理统计方法,对广西澄碧河水库上游流域气候变化特征进行分析,结果表明:水库降水量的变化以减少为主,春季、秋季和主汛期降水量的减幅均较大;平均气温均呈显著增高趋势,其中冬季增幅最大;蒸散量的变化均呈减少趋势.并探讨了气候变化对澄碧河水库上游流域的影响,总体来看,弊大于利;提出了水库应对气候变化的若干措施和建议.     

黄河源区陆面蒸散量的时空分布特征研究

基于修正的Penman-Monteith（P-M）模型,利用1980~2020年黄河源区的气象台站观测数据和陆-气间水热交换观测试验数据,计算出该区域的陆面参考蒸散量,分析了黄河源区蒸散量的时空演变特征,探讨了影响黄河源区蒸散量变化的原因。结果表明:（1）修正的P-M模型能较准确地估算黄河源区的参考蒸散量,与实际观测的相关系数在0.85以上。（2）黄河源区的蒸散量总体呈上升趋势,但在20世纪80年代中期和90年代中期均呈显著减少趋势;近年来,中部和西部地区的蒸散量呈减少趋势,而东部地区的蒸散量呈增加趋势。（3）黄河源区年蒸散量呈自东向西减小的分布特征,东、中、西部地区分别为473.5~516.0mm、437.6~473.5mm和386.3~437.6mm;四季蒸散量差异明显,夏季最大,春季和秋季次之,冬季最小。（4）黄河源区蒸散量随温度、风速和日照时数的增加而增大,随相对湿度和降水量的增大而减小。      

1960—2009年北京地区城市化背景下蒸发皿蒸发量的时空变化

利用1960—2009年北京地区20个气象台站的观测资料,分析了北京城区和郊区蒸发皿蒸发量的季节和年际变化趋势和特点,并探讨了城市化对北京地区局地气候的影响。结果表明:近50 a北京地区蒸发量有明显减小趋势,城区和郊区变化趋势分别为-88.1 mm/10a和-76.0 mm/10a。受城市化影响,北京城区蒸发量的变化主要与降水、日照时数、最低气温、气温日较差和平均风速的变化有关;郊区蒸发量的变化主要受相对湿度、日照时数、平均风速和空气饱和差的变化影响。总体而言,相对湿度、日照时数、最低气温、气温日较差和平均风速的变化对北京地区蒸发量的变化有显著影响。     

加强业务管理提高测报质量

我局从1999～2003年,测报工作连续4年未出现错情,在此期间共有1个250个班,9个百班无错通过上级业务部门验收.在仪器保管、使用、维护上符合要求,对外报送的各种表、簿都能做好出门合格.     

Quantifying the uncertainty of the annular mode time scale and the role of the stratosphere

The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998–2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.     

由中国历史气候记录对季风导致唐朝灭亡说的质疑

2007年1月4日杂志发表了Yancheva等10人的题为"Influence of the intertropical convergence zone on the East-Asian monsoon"(热带辐合带对东亚季风的影响)的论文[1],这是德国波兹坦地学研究中心气候动力与沉积学科的主管豪格(G.H.Haug)率领的科研小组的一项成果,认为是季风的变化引起的长期干旱导致了唐朝的灭亡.     

On the forecast of the onset and end of the convective season in the Amazon

Summary ?Some features of the climate system that can be considered predictors of the onset and end of the convective season over the Amazon were identified using one-month lag correlations and field composites. The fields analyzed were sea surface temperature (SST), outgoing long-wave radiation (OLR), vertical velocity and upper tropospheric winds. Warm (cold) anomalies in the SST in the tropical North Atlantic and the Caribbean Sea tend to be associated with delayed (early) onsets. Likewise, there is a tendency towards a delayed (early) end of the convective season with cold (warm) anomalies in these ocean regions. In addition, the SST in the cold tongue region of the equatorial Pacific is negatively, though weakly correlated with the onset date. The signal of this SST is more evident in the case of the end date, which is earlier with respect to its mean date in most of El Ni?o cases. The convective activity intensity itself conditions the onset and the end of the convective season, as it is evidenced by the behavior of the OLR and the vertical velocity fields. The more (less) intense the convective activity over South America during the preceding month, the earlier the onset and the later the end of the convective season on the Amazon region. The prediction of the onset and end dates of the convective season in the Amazon region was explored using a simple multiple regression technique based on the variables that have shown precursor signals with respect to these dates. The correlation coefficient between the predicted and the observed onset date is 0.81, and in the case of the end date, it is 0.76. The skill to predict early, delayed and normal categories was high, since in more than two thirds of the cases the category was successfully predicted, and there were no predictions of categories opposed to those observed. Received July 23, 2001; revised February 22, 2002; accepted April 26, 2002     

Comparing the theoretical versions of the Beaufort scale, the T-Scale and the Fujita scale

2005 is the bicentenary of the Beaufort Scale and its wind-speed codes: the marine version in 1805 and the land version later. In the 1920s when anemometers had come into general use, the Beaufort Scale was quantified by a formula based on experiment. In the early 1970s two tornado wind-speed scales were proposed: (1) an International T-Scale based on the Beaufort Scale; and (2) Fujita's damage scale developed for North America. The International Beaufort Scale and the T-Scale share a common root in having an integral theoretical relationship with an established scientific basis, whereas Fujita's Scale introduces criteria that make its intensities non-integral with Beaufort. Forces on the T-Scale, where T stands for Tornado force, span the range 0 to 10 which is highly useful world wide. The shorter range of Fujita's Scale (0 to 5) is acceptable for American use but less convenient elsewhere. To illustrate the simplicity of the decimal T-Scale, mean hurricane wind speed of Beaufort 12 is T2 on the T-Scale but F1.121 on the F-Scale; while a tornado wind speed of T9 (= B26) becomes F4.761. However, the three wind scales can be uni-fied by either making F-Scale numbers exactly half the magnitude of T-Scale numbers [i.e. F′half = T / 2 = (B / 4) − 4] or by doubling the numbers of this revised version to give integral equivalence with the T-Scale. The result is a decimal formula F′double = T = (B / 2) − 4 named the TF-Scale where TF stands for Tornado Force. This harmonious 10-digit scale has all the criteria needed for world-wide practical effectiveness.     

准两年振荡对大气中微量气体分布的影响

NCAR的包含化学、辐射、动力相互作用的两维模式（SOCRATES）移植回国后进行了初步的模拟试验,用以研究某些对环境问题重要的微量气体的化学、辐射、动力传输过程。在不考虑极地平流层云和气溶胶表面非均相化学等情况下,模式积分多年,计算结果稳定,模拟的风场、温度场显示出正常的季节变化,模拟的微量气体分布与卫星实测资料对照,结果也比较一致。为了探讨热带平流层风场的准两年周期振荡（QBO）对平流层微量气体分布的影响,我们做了QBO强迫的数值试验,即在模式中加入QBO强迫,并与不考虑QBO强迫的模拟结果对比。结果表明,QBO与其相关的次级环流所引起动力输送的变化,使平流层微量气体分布发生变化。     

Analysis of the Characteristics of the Low-level Jets in the Middle Reaches of the Yangtze River during the Mei-yu Season

Here, we analyze the characteristics and the formation mechanisms of low-level jets(LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts(ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets(BLJs) concentrated at heights of 900–1200 m.The BLJs occur most frequently at 230...     

流场配置及地形对西南低涡形成的动力作用

本文采用定常二层模式讨论较小地形及高、低层流场配置对西南低涡形成的动力作用。指出了西南低涡的形成是与盆地、河谷以及其上气流分层有关的一种定常态.在上、下为西风分层时期,低层的浅薄暖湿西风有利于西南低涡的形成.在上、下为东、西风分层时期,上层浅薄东风亦有利于西南低涡的形成.小型的凸起山脉对西南低涡的形成没有作用.