利用福建龙岩、漳州、泉州新一代多普勒天气雷达和厦门海沧双偏振雷达探测资料,采用动态地球坐标系下双雷达三维风场反演与拼图技术,基于天气研究和预报模式（Weather Research and Forecasting,WRF）及其资料同化系统,对登陆台风“莫兰蒂”（1614）引起的2016年9月14—15日福建强降水过程进行了双雷达风场反演拼图资料检验及其三维变分同化对强降水精细预报影响的数值试验,结果发现:（1）动态地球坐标系下双雷达反演风场能合理反映实际风场分布状况,其误差相对较小。相较厦门翔安风廓线雷达及厦门探空秒级测风数据,反演风风向（风速）平均绝对误差分别为7.8°（2.6 m/s）及3.4°（1.1 m/s）;（2）反演风场水平方向稀疏化对同化及预报结果极为重要,过密的反演风场资料会给同化及预报结果带来负效果。文中采用18、6、2 km 3重嵌套,在3重嵌套区域均进行同化以及仅在2 km区域进行同化两种情况下,均表现为当反演风场资料水平分辨率提高到0.1°时,同化分析及预报的台风环流开始受到负影响;且当反演风场资料水平分辨率越高时,负效果越明显。敏感性试验结果显示,分辨率取0.2°时数值预报效果最好;（3）以美国国家环境预报中心全球预报系统（National Centers for Environmental Prediction/Global Forecast System,NCEP/GFS）0.5°×0.5°分析场为初值,基于3个不同起报时刻（2016年9月14日14时、20时及15日02时）（北京时,下同）模拟的福建省境内台风内核雨带和螺旋雨带逐时演变、台风路径与强度、逐时降水TS评分和空间相关差异显著,其中14日14时起报试验效果最好;而14日20时起报试验效果最差,这与该试验初始台风大风轴风速明显偏大有关;（4）在上述3个不同起报时刻试验基础上,分别增加双雷达反演风场资料的三维变分同化后,福建境内地面风场和台风内核雨带、螺旋雨带逐时分布、逐时降水TS评分和空间相关、台风环流结构以及U、V风垂直廓线分布均有明显改善,最大正影响时效可达24 h;但仅对1—6 h时效内台风路径有改善。 相似文献
Using the regional climate model RegCM4.4.5, coupled with the land model CLM4.5, we investigated the effects of springtime soil moisture in the Indochina Peninsula on summer precipitation over the South China Sea and its surrounding areas in 1999. Results have indicated that there exists positive correlation between soil moisture and summer precipitation over the western Pacific Ocean and negative correlation between soil moisture and summer precipitation over the eastern Indian Ocean. Summer precipitation in the South China Sea and its surrounding areas responds to springtime soil moisture in the Indochina Peninsula (the northwest region is critical) because general atmospheric circulation is sensitive to the near-surface thermodynamic state. Increased (decreased) soil moisture would result in decreased (increased) local surface temperatures. Latitudinal, small-scale land–sea thermal differences would then result in northeasterly wind (southwesterly wind) anomalies in the upper layer and southwesterly wind (northeasterly wind) anomalies in the lower layer, which strengthen (weaken) monsoon development. As a result, precipitation would enter the Western Pacific region earlier (later), and water vapor over the eastern Indian Ocean would enter the South China Sea earlier (later), causing a precipitation reduction (increase) in the eastern Indian Ocean and increase (reduction) in the Western Pacific. 相似文献
A large amount of deep oil has been discovered in the Tazhong Uplift, Tarim Basin whereas the oil source is still controversial. An integrated geochemical approach was utilized to unravel the characteristics, origin and alteration of the deep oils. This study showed that the Lower Cambrian oil from well ZS1C (1x) was featured by small or trace amounts of biomarkers, unusually high concentration of dibenzothiophenes (DBTs), high δ34S of DBTs and high δ13C value of n-alkanes. These suggest a close genetic relationship with the Cambrian source rocks and TSR alteration. On the contrary, the Middle Cambrian oils from well ZS1 (2a) were characterized by low δ13C of n-alkanes and relatively high δ34S of individual sulfur compounds and a general “V” shape of steranes, indicating a good genetic affinity with the Middle–Upper Ordovician source rocks. The middle Cambrian salt rock separating the oils was suggested to be one of the factors responsible for the differentiation. It was suggested that most of the deep oils in the Tazhong Uplift were mixed source based on biomarkers and carbon isotope, which contain TSR altered oil in varied degree. The percentage of the oils contributed by the Cambrian–Lower Ordovician was in the range of 19–100% (average 57%) controlled by several geological and geochemical events. Significant variations in the δ34S values for individual compounds in the oils were observed suggesting a combination of different extent of TSR and thermal maturation alterations. The unusually high DBTs concentrations in the Tazhong-4 oilfield suggested as a result of mixing with the ZS1C oil (1x) and Lower Ordovician oils based on δ34S values of DBT. This study will enhance our understanding of both deep and shallow oil sources in the Tazhong Uplift and clarify the formation mechanisms of the unusually high DBTs oils in the region. 相似文献
