罗甸县春旱特征及成因浅析

根据2006年新颁布实施的《贵州省干旱标准》,利用罗甸县相关气候资料、春旱旱情资料和该县石漠化现状调查、森林资源调查等成果进行综合统计分析。结果表明:春旱是罗甸县发生最为频繁的气象灾害,重级和特重级春旱频率高、前春干旱重于后春干旱、跨季节连旱频繁是其基本特征。该县干旱的成因是该县地理位置、地形地貌、大气环流与生态环境等综合作用的结果,其石漠化较重、森林覆盖率低的北部乡镇春旱要重于石漠化程度较低、森林覆盖率较高的中南部乡镇。     

安顺市春旱情况浅析

运用统计方法对安顺的春旱情况进行分析,得出各种春旱出现的大致机率,并经过初步分析和应用已有的贵州春旱的科研成果,给出安顺市春旱的环流背景和主要影响系统,对今后春旱的预报有一定借鉴作用。     

安顺地区春旱情况初探

运用统计方法对安顺地区的春旱情况进行了研究,得出各种强度春旱型出现的大致机率,对今后春旱的预报有一定借鉴价值。     

近30a黔西南州气象干旱特征分析

该文利用黔西南州8个气象观测站近30 a(1981—2010年)降水资料、干旱灾情和历年气候整编资料,采用贵州省气象干旱标准中的降水距平百分率分析方法和黔西南州气象干旱与降水量的关系,对黔西南州气象干旱的时间和空间分布特征进行分析,结果表明:黔西南州气象干旱时间分布以秋旱和冬旱最多,春旱次之,夏旱最少,空间分布为北少南多。     

玛纳斯河流域春旱指标和规律的分析

通过对玛纳斯河流域春季农业用水的供需状况的分析,从水土平衡角度和从多年水份供应的平均状况,确定了两种春旱指标.对两种指标进行综合评定,确定出玛纳斯河流域春旱综合指标,并对其分布规律进行了分析.最后提出了防御春旱的对策建议.     

吉林省春季干旱成因分析

根据春旱指标,1951-1995年共确定了17个春旱年:1951、1954、1958、1963、1964、1966、1968、1970、1971、1974、1975、1977、1979、1981、1985、1987、1994年,平均2.6年发生一次。本文研究春旱发生的成因,主要研究影响我省春旱的北半球大气环流分布特征和影响系统,认为大气环流异常分布是春旱发生的直接原因。同时,通过对春旱变化规律的分析,厄尔尼诺、太阳活动与春旱的相关分析,地理位置和地形条件对春旱的影响等,认为春旱发生的成因和规律,是上述诸因素共同作用的结果。除些还受当地的土壤保水性能,蒸发量大小,地下水储量和水位高低,人为的因素等影响。因此,春旱灾害是一个复杂的综合因子影响结果。     

鹤壁市春旱动态监测及分析

利用鹤壁市淇县1971～2000年降水、底墒、蒸发资料,建立了适用于对春旱进行实时业务监测的动态模型;根据干旱指数大小确定春旱等级,并通过实例对比分析证实干旱指数在分析干旱动态演变过程中的作用.     

基于MCI干旱综合指数的贵州省干旱时空分布及灾情变化特征

基于贵州省83个国家级气象站1981年1月至2023年3月逐日气象干旱综合指数（Meteorological Drought Composite Index,MCI）及历史干旱灾情资料,从干旱过程演变特征、不合理跃变次数以及干旱日数与干旱灾情的相关性等方面,分析MCI在贵州省的适用性,揭示贵州省干旱时空分布及变化规律,并分析ENSO(El Ni?o-Southern Oscillation)事件对贵州省干旱的影响。结果表明：MCI在贵州省有较好的适用性。贵州西北部、北部及南部等地是干旱多发区,年干旱日数在40 d以上,东南部、西南部及中部一带干旱日数相对较少;西部春旱重、东部夏旱重。1981—2022年,贵州省平均年干旱日数和干旱强度总体呈增加趋势,其中西部增加趋势明显,东部呈减少趋势;秋季和冬季干旱强度呈增加趋势且秋季最明显,春季和夏季则呈减弱趋势。1981—2022年贵州省共发生3次特强、9次强、17次较强区域性干旱过程,一般区域性干旱过程27次,区域性干旱过程的持续天数、平均强度、平均影响面积以及综合强度指数均存在较大波动,总体呈弱增加趋势。贵州省及其9个市（州）1981—202...     

三江平原西部地区春旱对农业的影响

以汤原县为代表 ，分析了三江平原西部地区的春旱特点及成因；研究了不同时段春旱对农业生产的影响，提出了杭春旱的措施。     

北京地区春旱和春季第一场透雨指标的确定

利用北京地区１９５１－１９９５年降水和气温资料,探讨适用于春旱进行实时业务监测的春旱指标和春季第一场透雨的指标,并分析和讨论了指标的特点。     

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.     

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。     

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.     

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.     

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     

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...