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101.
多普勒天气雷达和L-波段探空雷达在探测中尺度天气方面,各有长处.前者具有较高的时空分辨率,缺点是需要反演.后者数据直接且要素多,但为局地数据,存在代表性的问题.利用多普勒雷达反演风廓线和300 m分辨率的探空数据相结合,可以很好的解释2006年8月26日发生在青岛的一次对流性暴雨过程的演变.在这次过程中,300 m分辨率的探空数据捕捉到了2 km左右高度上的冷平流信息,而多普勒雷达反演数据显示,温度平流对于对流的发生发展和消亡起着非常重要的作用.而且,多普勒雷达反演数据还揭示,在天气尺度影响系统仍然存在的背景下,冷平流的持续作用,引起了青岛上空大气状态的变化,导致整个降水过程结束. 相似文献
102.
基于多源遥感数据的日本海内波特征研究 总被引:1,自引:1,他引:1
日本海特殊的地理位置和复杂的地形使得该海域内波表征极为复杂,遥感是大范围观测内波的有效手段,已被广泛应用于内波的探测研究。本文利用MODIS、GF-1和ENVISAT ASAR遥感影像,开展了日本海内波特征研究。通过提取内波波峰线,生成了日本海内波空间分布图;获取了内波的波峰线长度和传播速度,并基于非线性薛定谔方程反演了内波振幅。研究结果表明,日本海内波分布范围宽广,不仅大陆架沿海区内波分布密集,深海盆地也探测到了大量内波;日本海北部45°N附近海域有少量内波出现,利用高分影像探测到朝鲜陆架浅海区有大量小尺度内波,大和海盆、大和隆起的西南部海域没有发现内波。日本海内波波峰线长达100多千米,深海区的传播速度大于1 m/s;浅海区内波振幅约10 m左右,深海区可达60 m以上。 相似文献
103.
准噶尔盆地南缘霍玛吐背斜带经历了复杂的构造变动和演化,地质条件非常复杂,对油气成藏条件特别是油气成因一直存在争议。通过对目前已发现气藏的天然气组分、碳同位素、轻烃组成等特征分析,探讨了霍玛吐背斜带天然气成因类型及来源。组分分析结果表明,霍玛吐背斜带天然气为有机成因湿气,主要为腐殖型干酪根裂解气;碳同位素分析结果表明,霍玛吐背斜带天然气主要为煤型气,既有热解气,也有裂解气;轻烃分析结果表明,霍玛吐背斜带天然气为典型煤型气。综合成因类型分析结果认为,该区天然气主要来源于侏罗系烃源岩的煤系地层,既有热解气,也有裂解气。 相似文献
104.
Chunli Liu Qiwei Sun Qianguo Xing Zhenlin Liang Yue Deng Lixin Zhu 《Ocean Science Journal》2017,52(1):1-10
The spatio-temporal variabilities in sea surface temperature (SST) were analyzed using a time series of MODIS datasets for four separate regions in the Yellow Sea (YS) that were located along a north-south axis. The space variant temporal anomaly was further decomposed using an empirical orthogonal function (EOF) for estimating spatially distributed SST. The monthly SSTs showed similar temporal patterns in each region, which ranged from 2.4°C to 28.4°C in the study years 2011 to 2013, with seasonal cycles being stronger at the higher latitudes and weaker at the lower latitudes. Spatially, although there were no significant differences among the four regions (p < 0.05) in any year, the geographical distribution of SST was characterized by an obvious gradient whereby SST decreased along the north-south axis. The monthly thermal difference among regions was largest in winter since the SST in the southeast was mainly affected by the Yellow Sea Warm Currents. The EOF1 mode accounted for 56% of the total spatial variance and exhibited a warming signal during the study period. The EOF2 mode accounted for 8% of the total variance and indicated the warm current features in the YS. The EOF3 mode accounted for 6% of the total variance and indicated the topographical features. The methodology used in this study demonstrated the spatio-temporal variabilities in the YS. 相似文献
105.
K.?N.?VisheratinEmail author A.?F.?Nerushev M.?D.?Orozaliev Xiangdong?Zheng Shumen?Sun Li?Liu 《Izvestiya Atmospheric and Oceanic Physics》2017,53(9):894-903
This paper reports investigation data on the temporal variability of total ozone content (TOC) in the Central Asian and Tibet Plateau mountain regions obtained by conventional methods, as well as by spectral, cross-wavelet, and composite analyses. The data of ground-based observation stations located at Huang He, Kunming, and Lake Issyk-Kul, along with the satellite data obtained at SBUV/SBUV2 (SBUV merged total and profile ozone data, Version 8.6) for 1980–2013 and OMI (Ozone Monitoring Instrument) and TOU (Total Ozone Unit) for 2009–2013 have been used. The average relative deviation from the SBUV/SBUV2 data is less than 1% in Kunming and Issyk-Kul for the period of 1980–2013, while the Huang He Station is characterized by an excess of the satellite data over the ground-based information at an average deviation of 2%. According to the Fourier analysis results, the distribution of amplitudes and the periods of TOC oscillations within a range of over 14 months is similar for all series analyzed. Meanwhile, according to the cross-wavelet and composite analyses results, the phase relationships between the series may considerably differ, especially in the periods of 5–7 years. The phase of quasi-decennial oscillations in the Kunming Station is close to the 11-year oscillations of the solar cycle, while in the Huang He and Issyk-Kul stations the TOC variations go ahead of the solar cycle. 相似文献
106.
为分析谷胱甘肽硫-转移酶M基因(glutathione S-transferases M,GSTM)与鱼类低温耐受性的相关性,本实验运用PCR-SSCP技术研究了130尾斑马鱼(Danio rerio)GSTM基因5?UTR、3?UTR和第一内含子序列的单核苷酸多态性(Single nucleotide polymorphisms,SNPs),同时分析了筛选到的基因型与其低温耐受性状的关联性。结果显示,在其5UTR区域检测到AB、BC、AC 3种基因型个体,共A、B、C 3个等位基因,其观测杂合度和期望杂合度分别是1.000和0.570,多态信息含量为0.472,所检测群体在该座位偏离了Hardy-Weinberg平衡;第1内含子中检测到DD、DE和EE 3种基因型个体,共D、E两个等位基因,其观测杂合度和期望杂合度分别为0.408和0.477,多态信息含量为0.362,群体在该座位符合Hardy-Weinberg平衡。3'UTR区域中没有发现多态性。上述2个SNP座位与斑马鱼低温耐受性状的关联分析结果表明,5'UTR区3种基因型与低温耐受性状均没有显著相关性(χ2=4.029,P0.05)。而第1内含子3种基因型与低温耐受性状显著相关(χ2=8.498,P0.05):DD基因型在耐低温群体中占优势(50.00%),并表现为对受低温胁迫斑马鱼的保护性因素(OR=0.520,95%CI=0.255–1.061),而DE基因型在不耐低温群体中占优势(51.31%),表现为低温胁迫下斑马鱼的危险因素(OR=3.012,95%CI=1.413–6.419)。研究结果为GSTM基因SNPs位点与斑马鱼低温耐受性能关联分析提供了依据,也将为海水经济鱼类抗寒标记筛选育种提供参考。 相似文献
107.
This paper is concerned with the formation control problem of multiple underactuated surface vessels moving in a leader-follower formation.The formation is achieved by the follower to track a virtual target defined relative to the leader.A robust adaptive target tracking law is proposed by using neural network and backstepping techniques.The advantage of the proposed control scheme is that the uncertain nonlinear dynamics caused by Coriolis/centripetal forces,nonlinear damping,unmodeled hydrodynamics and disturbances from the environment can be compensated by on line learning.Based on Lyapunov analysis,the proposed controller guarantees the tracking errors converge to a small neighborhood of the origin.Simulation results demonstrate the effectiveness of the control strategy. 相似文献
108.
泛素结合酶(UbcE2)是蛋白泛素化过程中所必需的酶,在泛素转移和底物的特异性识别方面发挥着重要的作用。本实验利用RACE技术克隆获得了全长为993bp的松江鲈泛素结合酶E2-D2基因cDNA序列(命名为TfUbcE2-D2),其开放阅读框为444bp,编码147个氨基酸。通过SMART预测得知,TfUbcE2-D2含有一个UBCc结构域。同源比对结果表明该基因与其他物种的同源性为92.31%。实时荧光定量PCR显示,TfUbcE2-D2广泛表达于松江鲈各组织,在肾脏中的相对表达量最高,其次为鳃。鳗弧菌(Vibrio anguillarum)刺激后,TfUbcE2-D2在血液、脾脏、肝脏和鳃中表达均上调,其中,脾脏和鳃中的表达量上调约40倍。由以上实验结果推测,TfUbcE2-D2可能参与松江鲈的先天免疫防御。 相似文献
109.
2009年冬、夏季南海北部超微型浮游生物的分布特征及其环境相关分析 总被引:1,自引:1,他引:1
2009年2月(冬季)和8月(夏季)在南海北部海域(nSCS)采用流式细胞术对聚球藻、原绿球藻、超微型光合真核生物3类超微型光合浮游生物和异养浮游细菌的丰度和碳生物量的时空分布特征进行了研究,并分析了其与环境因子之间的关系。结果表明,夏季聚球藻和原绿球藻的平均丰度高于冬季,超微型光合真核生物和异养浮游细菌的丰度反之,为冬季高于夏季。聚球藻、超微型光合真核生物和异养浮游细菌在富营养的近岸陆架海域丰度较高,而原绿球藻高丰度则出现在陆坡开阔海域。在垂直分布上,聚球藻主要分布在跃层以上,跃层以下丰度迅速降低;原绿球藻高丰度主要出现在真光层底部;超微型光合真核生物在水层中的高值同样出现在真光层底部,且与Pico级份叶绿素a浓度分布一致;异养浮游细菌在水体中的分布与聚球藻类似。这些分布格局的差异,取决于环境条件的变化和4类超微型浮游生物生态生理适应性的差异。在超微型光合浮游生物群落中,各类群碳生物量的贡献因季节和海域类型的不同而发生变化:聚球藻在夏季近岸陆架区占超微型光合浮游生物总碳生物量的41%,原绿球藻在陆坡开阔海成为主要贡献者(50%),超微型光合真核生物碳生物量以冬季为高(在近岸陆架区占比68%)。冬、夏季异养浮游细菌碳生物量均高于超微型光合浮游生物碳生物量。 相似文献
110.
Hans-Uwe Dahms Hyoung-Min Joo Jae Hyung Lee Mi Sun Yun So Hyun Ahn Sang Heon Lee 《Ocean Science Journal》2015,50(4):639-648
Demersally drifting organisms were collected at Ny Ålesund (Svalbård–Arctic Ocean) to study the taxon composition and relative abundances in the Arctic summer. Catch potentials of two collection devices for demersal drift were compared. A lowvolume submersible drift-pump and a drift-net unit were employed for the collection of demersally drifting biota, particularly for shallow aquatic habitats. With the exception of Appendicularia, Chaetognatha, Coelenterata, and Ctenophora, which were damaged at times, the pump catches were in good condition and sufficient for identification and quantification of less mobile fauna. A comparison of the two devices revealed that the drift-pump collected more specimens than the drift-net. However, the drift-net may have caused an underestimation of the abundances of invertebrates. No differences in identified taxon number and indices of richness, evenness and diversity were found. However, the proportion of invertebrate animals in the two devices was different for the three groups: zooplankton, macrofauna and meiofauna. At Svalbård, zooplankton, larvae of macrofauna, and meiofauna were successfully collected by the two collecting devices. However, the catchibility of the two devices in collecting various invertebrate taxa was different and, therefore, a sound ‘Device Effect’ was revealed. 相似文献