2003年气候异常对鱼台水稻生长的影响分析

根据2003年鱼台县气候特点，分析对水稻生长的影响，发现低温连阴雨天气是导致水稻严重减产的主要原因；通过分析水稻产量与气象因子的关系，找出影响水稻生长关键期的气象指标，并探讨相应对策。     

水稻生育期气候指标分析

对黑龙江省近十年水稻农业气象观测资料的分析，得出水稻生育期的分布及变化，发现水稻生育关键为出苗期分蘖期和抽穗期。各生育关键期气象影响指标共１７个。为气象对农业的影响评价，为水稻产量预报提供了依据。     

洋县水稻气候资源统计分析

通过统计分析获得水稻生育期中受气候波动影响的信息，确定水稻生育期间对光、热、水资源需求的关键期，并根据农业气候资源和水稻生物学特性设计水稻计划栽培方案。     

贵州省水稻实时农业气候综合评价方法研究

利用1979～1991年贵州水稻气象与物候观测等资料和数理统计分析方法，研究了水稻实时农业气候综合评价方法。应用该方法对贵州省水稻产量年景进行了验证，结果表明该方法对水稻生产具有较高的实用价值。     

水稻发育进程动态模拟

以水稻的生物学特性为依据，利用田间试验实例资料，建立了水稻发育进程动态模拟模式。实践表明，在其他条件均适宜的情况下，本模式能够较发地反映天气气候条件对水稻发育进程的影响，可用来预测水稻发育期，以指导大田生产管理。     

贵州水稻气象灾害及其对策研究(详细摘要)

水稻是贵州粮食作物中栽培面积最大。总产量最多、单产也最高的作物。建国以来，贵州水稻生产发展较快，总产量由1950年的211．1万吨增至1991年的428．7万吨，增长1倍多，但年际间的产量不稳定。产量波动主要受天气候条件尤以气象灾害影响最大。为此，必须掌握水稻栽培气象灾害发生的规律，采取相应对策与措施，才能减轻灾害造成的损失。本文分析了主要气象灾害对水稻的影响及其发生规律，提出了防灾减灾对策，对减轻灾害所造成的损失及促进水稻高产、稳产、优质、高效具有重要意义。1气象灾吝对水稻的影响1．1干旱1．1．旦春旱主要影响水稻…     

辽阳地区水稻丰歉模糊综合评判方法

运用现代统计学方法和模糊数学理论，普查确定了影响辽阳地区水稻产量的5项气候要素及其各自权重，建立了水稻产量的气候模型，揭示了各单因素对水稻丰歉的模糊关系。通过模糊运算，确立了水稻丰歉农业气候综合影响指标。     

水稻遥感估产的一种方法

该文利用NOAA/AVHRR空间覆盖度宽、资料获取时次多的特点，寻求预测北方一季稻产区水稻产量的最佳时期，利用植被指数建立水稻单产的预报模式，遥感估算水稻种植面积。研究表明，利用卫星遥感手段对水稻进行估产的精度高于常规农业气象模式，又可提高预报时效。     

广西两系杂交稻制种安全期气候

根据两系杂交水稻制种对气象条件的要求，利用广西80多站的气象资料，统计分析了广西各地两系统杂交水稻制种的安全期，提出了广西杂交水稻安全制种应注意的一些气候问题。     

清镇市站街镇K优5号、K优047杂交水稻绝收的调查分析

在对清镇市站街镇2001年K优5号和K优047杂交水稻绝收进行大田调查的基础上，根据水稻的生育特性，对比分析清镇市历年与2001年气候特点，找出了2001年K优5号和K优047杂交水稻绝收原因，为了合理利用光，热，水等气候资源，趋利避害，归纳出清镇水稻生育期气候特点，提出了在引种过程中应注意的问题。     

贵阳市供电量与气象要素的关系及其预测

通过对2000—2003年贵阳市供电量与温度、相对湿度、降水、风速、体感温度、日照时数等气象因子的相关分析研究，发现电量与气象因子的变化有明显的季节性差异，其中温度对供电量的影响最直接，湿度、降水、日照等因子的影响是间接性的，而平均风速对供电量无显著影响。     

2004年中国长江以南地区严重秋旱特征及其同期大气环流异常

利用2004年8～10月的中国160台站降水资料以及NCEP/NCAR再分析资料，分析了2004年秋季发生在中国长江以南地区的严重干旱（简称2004年长江以南秋旱）前兆和发展特征以及秋旱持续期间的东亚大气环流异常。结果表明:2004年长江以南秋旱是以8月在广西境内出现小范围干旱为前兆，9月扩展到长江以南中部地区，10月遍及整个长江以南地区而达到鼎盛的一个发展过程。2004年长江以南秋旱事件的发生、发展和鼎盛期都受到了同期东亚大气环流异常的很大影响:2004年秋季东南亚上空的整层经向水汽输送出现了显著的负异常，说明2004年秋季长江以南地区上空的整层水汽在经向上由南向北的输送减弱而从北向南的输送加强；850 hPa水汽输送的异常加强了从北向南的水汽输送，从而影响了秋旱的发展。结合2004年秋旱持续期间850 hPa 流场异常分析，2004年秋季850 hPa的流场在台湾海峡附近上空出现了一个气旋性的异常环流，它导致了西南水汽及其与越赤道气流和东南水汽的混合气流（10°N～20°N, 135°E～150°E）在向北的输送路径上发生改变，并且此混合气流进入内陆从而加强了大陆上空由北向南的干冷气流，进一步影响了秋旱的发展。通过分析850 hPa等压面上的垂直速度场发现:秋旱同期长江以南地区下沉气流异常，这种天气形势不利于降水的产生。2004年秋季长江以南地区受到了闭合高压——西太平洋副热带高压（简称西太副高）的长期控制，形成少雨的天气。除此之外，中高纬地区脊区前方和槽区的后方易于冷空气的南下输送， 这在很大程度上也促使了秋旱的发展。     

中国沙尘暴时空变化特征及日本、韩国黄沙的源地研究

利用1961～2000年中国681个站的气象实测资料,分析了近40年我国沙尘暴月际时空分布特征.结果表明,中国沙尘暴主要发生区域在青藏高原和北方干旱半干旱地区.12～3月,沙尘暴发生中心集中在青藏高原上,并随时间推移中心向北推移;4～6月在北方的干旱半干旱地区,其中4月是中国沙尘暴发生范围最大的月份;对比中国沙尘暴和日韩黄沙天气的月际分布,推测日韩两国冬季的黄沙大部分应该来源于青藏高原,春季青藏高原也有一定的贡献.由于沙尘暴发生在相差悬殊的不同海拔高度上,特别是在春季,扬起的沙尘在低层随涡旋系统而高层随行星西风向下游传输,可能是日韩观测到沙尘多层结构的重要原因之一.     

Resources of the ionized atmosphere as an aerosol source

The potential resources on the ion-stimulated syntheses effects of aerosol particles of lower troposphere in test sites in the arctic, mountain, arid and forest areas as the function of irradiation time and gas-precursor concentration were experimentally and theoretically evaluated. The dust-free outdoor air was irradiated with an ionization current of 10^− 6 A by α-rays from isotope ²³⁹Pu. The total output of radiolytic aerosols (RA) with a diameter of 3–1000 nm was found to be 0.05–0.1 molecules per 1 eV of absorbed radiation, while the physical upper limit is 0.25–0.4 molecules/eV. In an interval of exposition time from 6 to 800 s (adsorbed energy is 3 · 10¹²–10¹⁴ eV/cm³) the RA mass concentration at different sites was increased from 1–10 to 50–500 μg/m³. According to the liquid chromatography data the major RA material is the H₂O/HNO₃ solution with acid concentration  25%. The used physical model presents new aerosols as a product from small and intermediate ion association through formation of neutral clusters and describes adequately some of the peculiarities in field experiment data. Introducing SO₂, NH₃, and also hydrochloric, nitric and sulphuric acid vapours with concentration 0.1–1 mg/m³ in the irradiated air stimulated an increase of mass aerosol concentration by a factor of 8–30. The mean size also decreased by a factor of 3–5. These facts allowed us to expect that the chemical composition of radiolytic aerosols generated in outdoor air would noticeably differ after addition of the gas-precursors.     

Upper boundary of the bora as a stationary frontal surface

Summary For the inclined stationary internal atmospheric boundary as is the upper boundary of the bora flow down the lee-side slope of an orographic obstacle, the dynamic forces must be appropriately balanced, similar as at the atmospheric frontal surfaces. Starting from this idea, a model for the bora flow conditions was developed. Introducing some special suppositions, the model finally consists of four partial differential equations, which are solved numerically.Numerical experiments with the model by changing parameters such as friction and warm air stratification, as well as initial values of the flow: thickness, velocity, inclination and air mass temperature difference, show interesting results and finings. The shape of upper bora boundary and the distribution of the bora velocity above and downward the slope are graphycally presented, as they develop under the influence of different values of the mentioned parameters.With 5 Figures     

Skill of seasonal hindcasts as a function of the ensemble size

 Forecast skill as a function of the ensemble size is examined in a 24-member ensemble of northern winter (DJF) hindcasts produced with the second generation general circulation model of the Canadian Centre for Climate Modelling and Analysis. These integrations are initialized from the NCEP reanalyses at 6 h intervals prior to the forecast season. The sea surface temperatures that are applied as lower boundary conditions are predicted by persisting the monthly mean anomaly observed prior to the forecast period. The potential predictability that is attributed to lower boundary forced variability is estimated. In lagged-average forecasting, the forecast skill in the first two weeks, which originates predominately from the initial conditions, is greatest for relatively small ensemble sizes. The forecast skill increases monotonically with the ensemble size in the rest of the season. The skill of DJF 500 hPa geopotential height hindcasts in the Northern Hemisphere and in the Pacific/North America sector improves substantially when the ensemble size increases from 6 to 24. A statistical skill improvement technique based on the singular value decomposition method is also more successful for larger ensembles. Received: 22 February 2000 / Accepted: 6 December 2000     

Analysis of the Variations of the Whitecap Fraction as Measured in a Coastal Zone

The whitecap coverage generated by breaking waves plays a major role in the transfer of heat, momentum, water vapour and particles at the air-sea interface. The sea surface covered by whitecaps strongly depends on both the wind and the wave-field characteristics. In particular, in coastal zones, the variations of the whitecap fraction, commonly noted W, differ from open ocean conditions, due to fetch effects, wave-current interactions, bottom influence and irregular coastlines affecting both the wind properties and the wave development. We present an analysis of the whitecap-fraction variations using experimental data acquired during FETCH (Flux, Etat de mer, et Télédétection en Condition de fetcH variable), an experimental campaign that took place in the Gulf of Lion off the French Mediterranean coast in 1998. The data include various conditions of wave development associated with fetch and unsteady effects. The whitecap fraction W was measured using an original image processing technique applied to sea surface photography. Specific relationships between the whitecap fraction and both atmospheric and oceanic parameters are investigated, which confirm the suitability of the friction velocity for modelling W. However, W has also been parameterised using wave-parameter dependent relationships, which is of interest for very short fetches.     

Convective cloud downdrafts as the cause of large blowdowns in the Amazon rainforest

Summary Nelson et al. (1994) report a non-uniform distribution of large (0.33 to 33 km²) blowdowns in the rainforests of Amazonia. Occurrence of such large disturbances in the wet, low wind speed regime of the Amazon Basin cannot be explained by conventional mechanisms such as fire or hurricanes. While downdrafts from deep convective clouds are likely candidates, this paper draws upon meteorological observations from the central Amazon Basin to show that the requisite magnitudes of wind speed can be reached but only under conditions which would explain the observed horizontal distributions of the large blowdowns. Outflow velocities due to density driven downdrafts in the convective clouds are shown from observations to reach 15 m/s and correspond to the propagation velocities of longlived Amazon squall lines. Maintenance over 48 h of these squall lines depends upon the correspondence between the outflow velocity and the propagation velocity. The storms propagate within a basic current moving at 5 m/s, increasing the outflow velocities to 21 m/s. The development of a storm-generated pressure field must be called upon to increase the magnitude of the density and basic currents to more than 30 m/s. Such conditions occur only when the convection is embedded in squall lines which reach their diurnal maximum at locations nearly coincident with the observed locations of the maxima in large blowdowns. The characteristics of the observed blowdowns in terms of orientation, size and shape are consistent with winds derived from the postulated downward moving density currents being deflected and accelerated orthogonally at canopy top and forest floor.The causes and distribution of large blowdowns in the wet, low wind regime of the Amazon rainforest are shown to be important in explaining the disturbance regime of that system. Such disturbances are necessary in maintaining diversity of the system by locally disrupting the canopy, altering levels of incident radiation received at the surface and changing patterns of nutrient cycling, carbon uptake and storage.With 6 Figures     

CMIP5模式对ENSO现象的模拟能力评估

针对参与耦合模式比较计划(CMIP5)的17个海-气耦合模式对20世纪气候的模拟结果,从热带太平洋海表温度和大气海平面气压变化的综合分析角度较详细评估了模式对厄尔尼诺-南方涛动(ENSO)现象的模拟能力。结果表明,这些模式基本上能模拟出ENSO现象的一些主要特征,包括热带太平洋海温的空间分布及其时空演变特征、与海平面气压变化的关联、ENSO周期变化及锁相特征等,但不同模式的模拟结果仍然差异较大。(1)从模拟的热带太平洋年平均海温的偏差来看,多模式集合平均值与观测的均方根误差小于1.0℃,但单个模式的误差相对要大一些。误差较小的为1.2—1.3℃,多数模式在1.6℃以下,但也有个别模式的误差超过2.0℃。(2)从经验正交函数分解结果来看,热带太平洋实测月平均海表温度距平和海平面气压距平的年际尺度变化第1模态主要表现为ENSO变化特征,第2模态反映的是海温的长期变化趋势。只有少数几个CMIP5模式能够再现这种特征,多数模式所模拟的海温距平/海平面气压距平时空变化的第1、第2特征向量分布顺序与观测分析正好相反,ENSO变成了第2模态,趋势成了最主要的模态。尽管如此,所有模式都能模拟出南方涛动变化与热带太平洋海温距平时空变化的密切关联,无论是作为第1还是第2特征模态,所有模式模拟的南方涛动与热带太平洋海温距平时空变化都有密切相关。(3)谱分析结果表明,ENSO现象具有2—7年的周期,其中,4年的周期最明显。大多数模式模拟的ENSO周期在此范围内,但有些模式的主要周期偏短,为2年左右。个别模式的ENSO主要周期为11年,已超出2—7年的范围。(4)多数模式模拟的厄尔尼诺及拉尼娜的峰值出现在冬季(11—2月),与观测基本吻合。另有少数模式模拟的峰值出现在9—10月,比观测略提前。只有个别模式模拟的峰值出现在夏季,与观测相差太大。