太湖小时尺度水面蒸发特征及3种模型模拟效果对比

小时尺度水面蒸发可影响水面大气边界层热力和动力结构,分析湖泊小时尺度水面蒸发主要影响因素,选取准确模拟其特征的蒸发模型,将有助于改善流域天气预报和空气质量预报.基于太湖避风港站2012—2013年通量、辐射和气象观测数据,分析太湖小时尺度水面蒸发主要影响因子和3个模型(传统质量传输模型、Granger and Hedstrom经验模型、DYRESM模型)的模拟效果.结果表明:影响太湖小时尺度水面蒸发的主要因子为水气界面水汽压差和风速的乘积,而非净辐射.传统质量传输模型、Granger and Hedstrom经验模型、DYRESM模型模拟值与全年实测值的一致性系数分别为0.92、0.87和0.89,均方根误差分别为28.35、41.58和38.26 W/m~2.传统质量传输模型对太湖小时尺度水面蒸发的日变化和季节动态模拟效果最佳,其夜间模拟相对误差小于3%,除秋季外,其他季节的模拟绝对误差均小于4 W/m~2.Granger and Hedstrom经验模型系统性地高估太湖潜热通量,在大气较为稳定的午后(高估22~32 W/m~2)和冬季(高估72%)高估最为明显,模拟效果最差.DYRESM模型也系统地高估太湖潜热通量,模拟效果居中.考虑水汽交换系数随风速的变化特征将有助于改善传统质量传输模型和DYRESM模型对太湖小时尺度水面蒸发的模拟精度.     

基于空间一致性的双套站数据选取方法探索

国家级台站自动气象站双套运行后,将双套站产生的多套数据处理为一套数据的算法成为双套站投入业务运行前必须解决的重要问题。文章从数据"热备份"角度提出了基于空间一致性的主备法,在此基础上进一步从统计学基本原理以及保证数据连续角度提出了基于空间一致性的差值订正合成法两种数据处理算法。利用安徽省休宁站逐小时气温资料对两种算法结果的完整性和差异性进行了评估,评估使用的方法包括缺测率、差值均值、差值标准差、差值的一致率、超差率和粗差率等。评估结果表明:算法均能很好地保证数据的完整性;算法结果均与"真值"较为接近,基本能够反映大气真实情况,基于差值订正的"合成法"结果更优。最后利用新疆库车、安徽安庆等5个台站资料对算法涉及到的空间一致性方法进行了评估,结果表明该方法总体效果较好,尤其在相对湿度、气压和气温上具有很好的判别效果,而风速可能受局地地形或参考站选取影响效果略差。     

Impacts of human interventions on the seasonal and nodal dynamics of the M2 and K1 tidal constituents in Lingdingyang Bay of the Zhujiang River Delta,China

Natural and human-induced changes may exert considerable impacts on the seasonal and nodal dynamics of M₂ and K₁ tidal constituents. Therefore, quantifying the influences of these factors on tidal regime changes is essential for sustainable water resources management in coastal environments. In this study, the enhanced harmonic analysis was applied to extract the seasonal variability of the M₂ and K₁ tidal amplitudes and phases at three gauging stations along Lingdingyang Bay of the Zhujiang River Delta. The seasonal dynamics in terms of tidal wave celerity and amplification/damping rate were used to quantify the impacts of human-induced estuarine morphological alterations on M₂ and K₁ tidal hydrodynamics in inner and outer Lingdingyang Bay. The results show that both tidal amplification/damping rate and wave celerity were considerably increased from the pre-anthropogenic activity period (Pre-AAP) to the post-anthropogenic activity period (Post-AAP) excepting the tidal amplification/damping rate in outer Lingdingyang Bay, and the variations in outer Lingdingyang Bay was larger than those in inner Lingdingyang Bay. The alterations in these two parameters were more significant in flood season than in dry season in both inner and outer Lingdingyang Bay. The seasonal variability of M₂ and K₁ tidal amplitudes were further quantified using a regression model accounting for the 18.61-year lunar nodal modulation, where this study observes a considerable alteration in M₂ constituent owing to human interventions. During the Post-AAP, the M₂ amplitudes at the downstream station were larger than those that would have occurred in the absence of strong human interventions, whereas the opposite was true for the upstream station, leading to a substantial decrease in tidal amplification in outer Lingdingyang Bay. However, it is opposite in inner Lingdingyang Bay. The underlying mechanism can be primarily attributed to channel deepening and narrowing caused by human interventions, that resulted in substantial enlargement of the bay volume and reduced the effective bottom friction, leading to faster wave celerity and stronger amplified waves.     

Selected trace metals (As,Cd and Hg) distribution and contamination in the coastal wetland sediment of the northern Beibu Gulf,South China Sea

Contamination with As, Cd and Hg, their spatial and temporal distribution are reported from the coastal wetland sediments of the northern Beibu Gulf, South China Sea. The content of As, Cd, Hg and TOC in surface sediments is 8.1 ± 5.8 μg g^?1, 0.08 ± 0.14 μg g^?1, 0.034 ± 0.028 μg g^?1 and 0.45 ± 0.39%, respectively. The mean sedimentation rates are 0.93–1.37 cm year^?1 during 1920s to 2008 determined by ²¹⁰Pb and ¹³⁷Cs dating in three cores. The vertical profiles of As, Cd and Hg content in the cores retrieved from Qin and Nanliu River estuaries show increasing trends during 1985–2008 due to anthropogenic impact caused by local economic development. Locally the surface sediments have potential ecological risk of As to benthos according to the NOAA sediment quality guidelines.     

汞观测中干扰因素的研究

本文通过实验及机理的分析研究表明：１．测汞仪气路中硅胶管对汞的的吸附水平受其本身温度的影响。温度升高，吸附汞的能力下降，释放其吸附汞的速度加快。在一定的温度下，硅胶管存在一个管内吸附汞与通过其中的气体中汞的释放和吸附的平衡；２．观测室温度的变化，除通过影响仪器气路（如硅胶管等）的温度百而影响观测结果外，主要是影响观测测室内壁汞进入空气的量，而影响空气汞本底，严重时可引起本底值值发生数十位的变化；３     

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Web空间数据编辑中数据一致性保护机制

对当前三种Web空间数据编辑中数据冲突解决方案进行了比较,并提出了在Internet环境下采用版本管理机制进行多用户空间数据编辑,防止编辑过程中数据冲突的发生,尽可能维护空间数据的完整性和一致性,实现了空间数据的远程更新和多用户地图编辑的并发更新。     

海底天然气水合物的饱和度预测技术

海底天然气水合物的储量主要取决于水合物的分布面积、水合物稳定带的厚度、沉积层的孔隙度及水合物的饱和度 (或充填率 )等 ,其中水合物在沉积物孔隙中的饱和度对其储量的估计具有重要意义。目前很难通过原地直接测量来获得这种饱和度数据 ,一般根据地球化学或地球物理方法取得。水合物饱和度预测技术主要有 :利用岩心孔隙水氯离子浓度、地球物理测井、地震波速度等间接手段。每一种技术都不是完善的 ,而海底含水合物的沉积物又是一个复杂的系统 ,在预测中应根据实际情况选择比较合适的方法 ,并尽量选择一种以上的方法或模型作多方法校正     

近50年安徽省太阳总辐射的时空变化特征

采用1961—2010年安徽省辐射观测数据和常规气象要素观测资料,建立了太阳总辐射的气候学计算方法;进而推算了安徽省各地太阳总辐射,并采用趋势分析、突变检验和小波分析等方法研究了其时空变化特征。结果表明:以理论天文辐射为起始值所建立的全省统一公式,能够较好的拟合安徽省月尺度的太阳总辐射值。根据公式推算的安徽省各地太阳总辐射资源的丰富程度以3级为主,空间分布呈北多南少的特征,季节分布为夏多冬少单峰型,但在梅雨期存在波谷。近50年来安徽省各地太阳总辐射量基本呈一致的减少趋势,全省平均下降趋势为每10年减少0.31 MJ·m-2·d-1,近年来辐射下降趋缓。安徽省太阳总辐射在20世纪80年代初存在一次突变现象;近50年总辐射量以准10年和4~6年左右周期振荡较为明显,而20世纪80年代以来年代际振荡信号减弱,并且太阳总辐射气候态以偏少为主。     

大震前地下流体的远场中期前兆异常

通过研究安微省五河井水位、沪江井井压和流量的观测资料,笔发现了大震前远场中期异常的证据。菲律宾８．０级地震（１９９０年７月１６日）前,五河井（Δ＝２０３３ｋｍ）水位的Ｍ２波的振幅比α和相位差Δθ,均有近１７个月的低值异常;庐江井（Δ＝１８００ｋｍ）井压和流量均存在近３６个月的低值异常。台湾海峡７．３级地震（１９９４年９月１６日,五河井（Δ＝１１２１ｋｍ）水位Ｍ２波α和Δθ以及庐江井（Δ＝９３０ｋ