Long-term simulations of the sulfur concentrations over the China, Japan and Korea: A model comparison study

Three comprehensive acid deposition models were used to simulate the sulfur concentrations over northeast Asia over the period covering entire year of 2002, and discussed the aggregated uncertainties and discrepancies of the three models. The participating models are from the countries participating in the project of Longrange Transboundary Air Pollutants in Northeast Asia (LTP): China, Japan and Korea. The Eulerian Model-3/CMAQ (by China), Regional Air Quality Model (RAQM, by Japan), and Comprehensive Acid Deposition Model (CADM, by Korea) were employed by each country with common emissions data established by the administrative agencies of China, Japan and Korea. The episodic simulation results between 1 to 15, March 2002 are also presented, during which aircraft measurements were carried out over the Yellow sea. The episodic results show both a wide short-term variability in simulations against measurements, and maximum concentration differences of 3～5 times among the three models, requiring that further attention before confidence among the three models can be claimed for short-term simulations. However, the year-long cumulative simulations showed almost the same general features, with lower aggregated uncertainties between the three models, produced by the long term integration over northeast Asia.     

云南省冰冻灾害气候区划

通过对1951-2007年云南124个测站的冰冻样本及其对应的气温、风速、相对湿度等数据进行了统计分析,根据冰冻样本概括率和冰冻天气概括率建立了冰冻天气判别式。利用Cressman客观分析方法,对1958-2007年11月～次年4月逐日地面气温、相对湿度和风速进行了1 km×1 km细网格插值,在插值中考虑了气象要素随...     

边界层风廓线仪多普勒频谱高度图综合应用初探

文章介绍了边界层风廓线仪多普勒频谱高度图的原理,并且给出了无降水、有降水、降雪、速度折叠、地物杂波、外界信号干扰等典型的多普勒频谱高度图型。研究发现,多普勒频谱高度图除了可以从中提取测风产品所需的数据外,该在线显示的图形还实时提供了许多其他潜在的气象信息,并可用于：连续监视测站上空天气;提前了解测站上空风的垂直切变;发现并确定降水起始时间;在线估测风向风速;实时判别降水云底高度和0°层的范围;验证和解释风羽剖面图产品中的奇异现象;帮助固定和移动风廓线仪选址;诊断风廓线仪系统故障;评价风廓线仪系统软/硬件性能优劣等。文章指出：深入发掘边界层风廓线仪在降水天气系统中进行高时间密度探测的潜力,使得它可以晴雨两用,对今后将边界层风廓线仪配备到一般气象观测站,提高单站天气监测/预警能力和开展精细化天气预报意义深远。文章还对当前商业化的边界层风廓线仪提出了具体的改进意见,以满足频谱在线分析的需要。     

开花后淹水对小麦旗叶叶肉细胞及产量的影响

选用小麦品种济麦20和泰农18,采用池栽补灌淹水方法,研究开花期及灌浆期3、6、9、12d淹水对小麦旗叶叶肉细胞形态及籽粒产量的影响.开花期淹水,减少叶肉细胞的裂解,延缓了旗叶衰老;灌浆期淹水,则加剧了叶肉细胞的裂解,旗叶的衰老加速.除淹水3d外,两时期6-12 d淹水均引起籽粒产量降低.产量降低的主导因素是粒数的减少,其次是粒重的降低.     

FY-3A MWHS资料的质量控制——以四川“8.19”暴雨为例

FY-3A MWHS微波湿度计辐射率资料空间分辨率高,同化后能有效地提高中尺度系统的数值预报的准确率。但如果不进行质量控制,任由误差大的离群微波资料进入同化系统,将会降低分析场精度,影响预报准确率。本文选取2010年8月17~19日的暴雨个例,应用主成分分析(PCA)方法,找出FY-3A微波湿度计数据中的离群值。结果表明:采用PCA方法,3天的资料总共识别出148个离群值样本,占总数的19.3%,其中通道三离群值占5.5%,通道四离群值占8.2%,通道五占5.4%。去除这些离群值后的MWHS数据总体分布,更靠近数据中心,各EOF方差贡献更加平滑。这说明PCA方法是一种可以抵抗少数离群值对总平均值影响的有效质量控制方法。      

Comparison of three methods for estimating the sea level rise effect on storm surge flooding

Two linear methods, including the simple linear addition and linear addition by expansion, and numerical simulations were employed to estimate storm surges and associated flooding caused by Hurricane Andrew for scenarios of sea level rise (SLR) from 0.15 m to 1.05 m with an interval of 0.15 m. The interaction between storm surge and SLR is almost linear at the open Atlantic Ocean outside Biscayne Bay, with slight reduction in peak storm surge heights as sea level rises. The nonlinear interaction between storm surges and SLR is weak in Biscayne Bay, leading to small differences in peak storm surge heights estimated by three methods. Therefore, it is appropriate to estimate elevated storm surges caused by SLR in these areas by adding the SLR magnitude to storm surge heights. However, the magnitude and extent of inundation at the mainland area by Biscayne Bay estimated by numerical simulations are, respectively, 22–24 % and 16–30 % larger on average than those generated by the linear addition by expansion and the simple linear addition methods, indicating a strong nonlinear interaction between storm surge and SLR. The population and property affected by the storm surge inundation estimated by numerical simulations differ up to 50–140 % from that estimated by two linear addition methods. Therefore, it is inappropriate to estimate the exacerbated magnitude and extent of storm surge flooding and affected population and property caused by SLR by using the linear addition methods. The strong nonlinear interaction between surge flooding and SLR at a specific location occurs at the initial stage of SLR when the water depth under an elevated sea level is less than 0.7 m, while the interaction becomes linear as the depth exceeds 0.7 m.     

云南不同气候带极端气温变化趋势

利用1975-2008年云南6个气候代表站的最高气温、最低气温和平均气温资料,分析了气温序列的变化趋势,探讨了可能的形成原因.结果显示,各代表站的气温总体上呈上升趋势,但气温变化率的大小与其所处的气候带之间没有明显的规律性差异.代表高原气候的香格里拉站其气温增暖趋势最突出,代表北亚热带、中亚热带和南亚热带站点的气温与其有相似的变化趋势,主要表现为最低气温增温速率最大,平均气温次之,最高气温最小,而气温日较差(DTR:Differenceof Temperature Range)有明显减小趋势.温带和北热带代表站气温的变化则有不同的特征,温带的变化表现为最高气温显著上升,最低气温上升速率略小于平均气温的上升速率,DTR变化不显著;北热带的变化表现为平均气温增温速率最大,最低气温次之,最高气温最小,DTR变化不显著.对各站相对暖日、冷日、暖夜、冷夜和霜日的逐年统计分析表明,总体上云南的冷事件在减少,而暖事件增多.     

云南省雷灾特征分析及灾情评估

根据云南省2007 2008年的雷电灾害资料以及地闪资料,分析了云南省16个地级市的雷电灾害分布特征,讨论了雷灾分布与地闪分布的关系,并从雷灾记录中提取了6个灾度指标,通过AHP法(层次分析法)建立灾情评估层次模型和灾度评估方程,计算了云南省522次雷灾的灾度值,用SAS中聚类分析过程将灾度值分为4级,并统计分析了各级雷灾在各地区的分布情况,得出云南雷电灾害中小型雷灾分布较广、出现几率较大,而大型和特大型雷灾发生几率较低、主要集中在昆明和德宏地区.该文结论为区域防雷减灾规划提供了科学依据.     

广西霜日气候变化特征

通过对1951-2012年广西90个气象站霜日分布及变化特征的分析得出:广西霜日具有北多南少与东多西少、而初霜日有北早南晚和终霜日有南早北晚的分布特征,广西霜日存在明显的12a、10a、2a周期震荡。     

回波对消中盲源分离算法的研究与仿真

盲源分离因为可以仅根据接收到的观测信号来估计还原源信号,成为近年来在信号处理领域的研究热点.针对盲源分离中的基于峭度的独立分量分析算法在源信号还原的过程中计算量较大的问题,采用共轭梯度方法对独立分量分析法进行优化,优化后的算法收敛速度更快,稳态误差变小.Matlab仿真实验表明,优化后的独立分量分析算法收敛更快,实际分离效果更好.