基于集合经验模态分解的新疆地区温度场预测评估

综合运用经验正交分解法(EOF),集合经验模态分解(EEMD)和最小二乘支持向量机（LS SVM）,构建新疆地区候平均温度距平场预测模型。采用EEMD分别对经过EOF分解得到的前3个模态的时间系数进行分解,对分解得到的结果运用最小二乘支持向量机进行预测并重构得到了各个时间系数的预测结果,将时间系数预测的结果与空间场重构得到了候平均温度距平场的计算结果,在候平均的基础上计算得到了旬平均的结果,在旬平均的基础上计算得到了月平均的结果。通过采用距平相关系数(ACC〖WTBZ〗),预报技巧(SS)〖WTBZ〗和同号率对结果进行评估显示,对于候平均预测,其在前20候内的预测较为理想,平均ACC〖WTBZ〗达到了0.32,平均SS〖WTBZ〗达到了0.70,平均同号率达到了0.80。对于旬平均的预测,其在前10旬内较为理想,10旬以内平均ACC〖WTBZ〗达到了0.50,平均SS〖WTBZ〗达到了0.50,平均同号率达到了0.50。对于月平均的预测,3个月的预测平均ACC〖WTBZ〗达到了0.50,平均SS〖WTBZ〗达到了0.50,平均同号率达到了0.80。3个月内的短期气候预测具有较高的水平。     

深埋长大隧道围岩分类评价的探讨与应用

随着国内外深埋长大隧道规模的增大和工程项目的增多，其围岩分类，评价愈显重要和迫切。深埋长大隧道地质环境条件复杂，施工前期勘探工程量少，控制程度低，勘夺分类，评价极为困难。在总结当前隧道围岩分类，评价方法的基础上，针对其目前存在的问题及不足，结合具体工程探讨了深埋长大隧道围岩分类，评价的实现方法问题。     

夏季中国中东部不同历时降水时空分布特征

利用1961~2012年台站逐时降水资料,分析了夏季中国中东部不同历时降水的主要气候分布和长期变化特征,为深入认识其时空变化规律和形成机理奠定基础。分析结果表明,降水事件的平均历时由南向北呈"短—长—短"分布型,华南和北方地区以6 h以下的短历时降水为主;而中部地区(28°N~37°N)6 h以上长历时降水占总降水量60%以上。随着降水历时的增加,小雨事件(0.1~1.0 mm/h)的发生概率降低,中雨事件(1.1~10.0 mm/h)的发生概率升高;大雨、暴雨事件(10.0 mm/h)更易出现在35°N以南历时偏短的降水事件中。1961~2012年,中国中东部总降水量呈"南升北降"的趋势分布,夏季南方大部分地区降水强度、时数和事件数均呈上升趋势;而北方地区降水时数和事件数显著减少,不过降水强度呈增强趋势。中东部降水历时总体呈上升趋势,尤其以我国长江与黄河之间的中部地区变化最为显著。同时,该地区短历时(1~6 h)降水无显著的年代际转折,长历时(6 h)降水的年代际增加是20世纪70年代末至20世纪90年代初降水增多的主要原因。20世纪90年代初期以来,南方地区降水的年代际增多则是长、短降水共同作用的结果,但超过6 h降水的影响范围更广,且影响中心较短历时降水偏北。     

天津市供水量与气象因子相关分析及预测模型

利用天津市某区2017年逐日、2017年7月逐时供水资料和气象资料,分析日、时供水量的变化特征及其与气象因子的关系,建立基于气象因子的日供水量预测模型。结果表明:夏季供水量最多,秋季、春季的次之,冬季的最少;日供水量存在明显的节假日效应,特别是在春节长假期间供水量下降明显。分析日供水量与气象因子的相关系数发现,除冬季外,日供水量与气温相关性较高,与其他气象因子相关系数季节差异明显。7月供水时变化特征主要受居民工作生活习惯影响,同一时次的供水量与蒸发量、相对湿度和整点气温相关性较高,但有明显的滞后性,13时的气象条件对全天总供水量影响较大。综合以上分析结论,建立多元回归日供水量预测模型。模型预测结果平均误差为1.48%,可作为日供水量预测参考依据。     

Atmospheric Environmental Capacity of SO2 in Winter over Lanzhou in China： A Case Study

The total emission control method based on atmospheric environmental capacity is the most effective in air pollution mitigation. The atmospheric environmental capacities of SO2 on representative days over Lanzhou are estimated using the numerical models RAMS, HYPACT and a linear programming model, according to the national ambient air quality standard of China （NAAQSCHN）. The results show that the fields of meteorological elements and SO2 simulated by the models agree reasonably well with observations. The atmospheric environmental capacity of SO2 over Lanzhou is around 111.7 × 10^3 kg d^-1, and in order to meet the air quality level Ⅱ of the NAAQSCHN, SO2 emissions need to be reduced by 20%.     

临近绿洲的沙漠上空近地面层内水汽输送特征

1991年7月在HEIFE实验区沙漠站进行了一次水汽输送观测实验。观测发现近地面层内比湿廓线常常出现极小值，该极小值高度为零水汽通量面的高度。这个高度以上水汽向下输送，廓线呈逆湿特征，这个高度以下水汽向上输送，廓线呈蒸发特征。沙漠上空近地面层内水汽不是常通量，在一个固定高度上观测到的水汽通量和“潜热通量”不能代表地面的蒸发量和潜热通量。     

呼和浩特站新一代天气雷达疑难报警故障分析

随着新一代天气雷达在内蒙古的布点不断增多,以及应用范围的不断扩大,这对雷达技术保障工作提出了更高的要求。针对呼和浩特站雷达故障个例,探讨如何进行雷达相关部分的原理分析、判断定位和故障排除,并总结了故障排除的方法。     

What controls early or late onset of tropical North Atlantic hurricane season?

The occurrence of first hurricane in early summer signifies the onset of an active Atlantic hurricane season. The interannual variation of this hurricane onset date is examined for the period 1979-2013. It is found that the onset date has a marked interannual variation. The standard deviation of the interannual variation of the onset day is 17.5 days, with the climatological mean onset happening on July 23.A diagnosis of tropical cyclone (TC) genesis potential index (GPI) indicates that the major difference between an early and a late onset group lies in the maximum potential intensity (MPI). A further diagnosis of the MPI shows that it is primarily controlled by the local SST anomaly (SSTA). Besides the SSTA, vertical shear and mid-tropospheric relative humidity anomalies also contribute significantly to the GPI difference between the early and late onset groups.It is found that the anomalous warm (cold) SST over the tropical Atlantic, while uncorrelated with the Niño3 index, persists from the preceding winter to concurrent summer in the early (late) onset group. The net surface heat flux anomaly always tends to damp the SSTA, which suggests that ocean dynamics may play a role in maintaining the SSTA in the tropical Atlantic. The SSTA pattern with a maximum center in northeastern tropical Atlantic appears responsible for generating the observed wind and moisture anomalies over the main TC development region. A further study is needed to understand the initiation mechanism of the SSTA in the Atlantic.     

Estimation of the monthly precipitation predictability limit in China using the nonlinear local Lyapunov exponent

By using the nonlinear local Lyapunov exponent and nonlinear error growth dynamics, the predictability limit of monthly precipitation is quantitatively estimated based on daily observations collected from approximately 500 stations in China for the period 1960–2012. As daily precipitation data are not continuous in space and time, a transformation is first applied and a monthly standardized precipitation index (SPI) with Gaussian distribution is constructed. The monthly SPI predictability limit (MSPL) is quantitatively calculated for SPI dry, wet, and neutral phases. The results show that the annual mean MSPL varies regionally for both wet and dry phases: the MSPL in the wet (dry) phase is relatively higher (lower) in southern China than in other regions. Further, the pattern of the MSPL for the wet phase is almost opposite to that for the dry phase in both autumn and winter. The MSPL in the dry phase is higher in winter and lower in spring and autumn in southern China, while the MSPL values in the wet phase are higher in summer and winter than those in spring and autumn in southern China. The spatial distribution of the MSPL resembles that of the prediction skill of monthly precipitation from a dynamic extended-range forecast system.     

Diurnal and inter-monthly variation of land surface heat fluxes over the central Tibetan Plateau area

Summary The energy and water cycle over the Tibetan Plateau play an important role in the Asian monsoon system, which in turn is a major component of both the energy and water cycles of the global climate system. Using field observational data observed from the GAME/Tibet (GEWEX (Global Energy and Water cycle Experiment) Asian Monsoon Experiment on the Tibetan Plateau) and the CAMP/Tibet (CEOP (Coordinated Enhanced Observing Period) Asia-Australia Monsoon Project (CAMP) on the Tibetan Plateau), some results on the local surface energy partitioning (diurnal variation, inter-monthly variation and vertical variation etc.) are presented in this study.The study on the regional surface energy partitioning is of paramount importance over heterogeneous landscape of the Tibetan Plateau and it is also one of the main scientific objectives of the GAME/Tibet and the CAMP/Tibet. Therefore, the regional distributions and their inter-monthly variations of surface heat fluxes (net radiation flux, soil heat flux, sensible heat flux and latent heat flux) are also derived by combining NOAA-14/AVHRR data with field observations. The derived results were validated by using the ground truth, and it shows that the derived regional distributions and their inter-monthly variations of land surface heat fluxes are reasonable by using the method proposed in this study. Further improvement of the method and its applying field were also discussed.