陆海交界区域厘米级精度似大地水准面的确定

为了得到我国某陆海交界区厘米级精度的区域（似）大地水准面,利用43个高精度GPS／水准点和1045个实测重力点数据对EGM96,WDM94和GFZ计算的局部重力（似）大地水准面进行了比较与评价。结果表明,在该测区用移去．恢复法确定重力（似）大地水准面时,EGM96应该是首选参考重力场模型。该测区处在陆海交界处,海域无GPS／水准数据。经比较发现,采用距离倒数加权平均法将该区重力似大地水准面拟合于GPS／水准数据比在大范围使用的多项式法效果更好。采用该方法计算的测区（似）大地水准面精度优于3cm。     

南海在1997/1998年El Ni(~n)o事件后的异常变化

基于NOAA OISST.V2月平均SST资料和FSU月平均风应力资料对南海的SST和风场异常进行了分析,发现:南海对1997/1998年El Nino事件响应最为强烈,并在1997/1998年冬季和次年的夏季SST存在2个异常高峰值,风速存在2个异常减小的极值.为研究南海环流在1997/1998年的异常变化,利用ECOM水动力模型计算了1995-2000年的南海环流场,分析了1998年1月和8月南海水位和环流的异常分布,二者均存在显著的异常:①1月,整个南海海盆为正的水位异常,流场为反气旋异常环流,冬季控制整个南海海盆的气旋式环流减弱;②8月,南海海盆水位为正异常,特别是越南东部海区出现较强的正水位异常,南海南部的高水位中心扩大北移;异常流场表现为南部为气旋式异常环流,北部为反气旋的异常环流,且在越南东部海区形成非常强的反气旋异常环流中心,使得控制南海南部的反气旋环流和北部的气旋环流均减弱.风应力的分析表明,风应力旋度的异常变化是南海环流年际异常变化的主要因素.     

FY-3A/MERSI、MODIS C5.1和C6气溶胶光学厚度产品在中国区域与地面观测站点的对比分析

准确获取气溶胶光学厚度对于气候变化研究和大气环境监测具有重要意义。通过波长插值和时空匹配方法,利用气溶胶自动观测站网（AERONET）观测的气溶胶光学厚度（AOD）对风云3A/中分辨率光谱成像仪（FY-3A/MERSI）、Terra（Aqua）/MODIS的C5.1（Collections 5.1）和C6（Collections 6）气溶胶光学厚度产品在中国区域的反演精度进行验证分析。结合一次发生在中国境内的沙尘天气与一次严重雾霾天气个例,分析上述卫星气溶胶光学厚度的分布特征。研究结果表明,（1）FY-3A/MERSI AOD的反演精度较高（R=0.887,RMSE=0.234）,其值低于AERONET的观测值（Bias=-0.293）。（2）在不同的下垫面下,各种卫星暗像元算法AOD产品反演精度有差异,植被覆盖情况越好,反演精度越高,而植被很少的地区,即亮地表甚至没有反演值。（3）MODIS C5.1深蓝算法产品能在亮地表地区反演AOD,但效果不佳。MODIS C6中的深蓝算法产品在不同下垫面的反演精度都很高（RMSE为0.096-0.127）。（4）在不同季节的对比中,各种卫星AOD产品在夏季的反演精度最差,而反演最好的季节各有不同。（5）在一次沙尘天气污染与一次严重雾霾天气个例中,中国西部与北部区域,MODIS C6深蓝算法AOD的监测效果优于其他算法AOD;MERSI AOD产品在此区域的分布不连续。总体而言,MODIS C6 AOD分布比MODIS C5.1产品连续,MODIS 3 km产品在相同区域的AOD值高于其他产品。以上结论可为卫星AOD产品在中国区域的使用提供参考。      

Formation and Development of a Mountain-induced Secondary Center inside Typhoon Morakot(2009)

The structural evolution of Typhoon Morakot(2009) during its passage across Taiwan was investigated with the WRF model. When Morakot approached eastern Taiwan, the low-level center was gradually filled by the Central Mountain Range(CMR), while the outer wind had flowed around the northern tip of the CMR and met the southwesterly monsoon to result in a strong confluent flow over the southern Taiwan Strait. When the confluent flow was blocked by the southern CMR, a secondary center(SC) without a warm core formed over southwestern Taiwan. During the northward movement of the SC along the west slope of the CMR, the warm air produced within the wake flow over the northwestern CMR was continuously advected into the SC, contributing to the generation of a warm core inside the SC. Consequently, a well-defined SC with a warm core, closed circulation and almost symmetric structure was produced over central western Taiwan, and then it coupled with Morakot's mid-level center after crossing the CMR to reestablish a new and vertically stacked typhoon. Therefore, the SC inside Morakot was initially generated by a dynamic interaction among the TC's cyclonic wind, southwesterly wind and orographic effects of the CMR, while the thermodynamic process associated with the downslope adiabatic warming effect documented by previous studies supported its development to be a well-defined SC. In summary, the evolution of the SC in this study is not in contradiction with previous studies, but just a complement, especially in the initial formation stage.     

青藏高原感热气泵影响亚洲夏季风的机制

本文回顾了二十年来关于青藏高原感热驱动气泵(TP-SHAP)及其影响亚洲夏季风的研究进展,并从能量(θ)、位涡—加热(PV–Q)、和角动量守恒(AMC)的不同角度阐述其影响机制。指出高原斜坡上的表面感热加热改变了移向高原的大气质块的能量从而出现垂直抽吸的重要性。强调了高原加热产生的位涡强迫在近地层制造了强度大范围广的、环绕高原的气旋式环流,把丰沛的水汽从海洋输运到大陆,为季风对流降水提供充足的水汽条件。证明高原加热还通过改变其上空的温、压场的结构从而制造出高原上空近对流层顶的绝对涡度和位涡的最小值,在角动量平衡约束下,在亚洲季风区激发出与Hadley环流反向的季风经圈环流,从而为季风发生发展提供了大范围上升运动的背景。文中还对近年来有关青藏高原影响亚洲夏季风机制的讨论进行概述,并展望了未来的研究方向。     

INFLUENCE OF THE ASIAN SUMMER MONSOON ON THE MIGRATION PHENOLOGY AND POPULATION DYNAMICS OF NILAPARVATA LUGENS (ST?L) IN CHINA

With the aim to examine variations in the migration phenology and population of N. lugens along with the advance/retreat of the Asian summer monsoon(ASM) and lay the foundation for further study on predicting the timing and location of N. lugens outbreak, correlation analysis and spatial analysis were applied for estimating the impact of the ASM and its related meteorological factors on the migration phenology and population of N. lugens in China in this paper. The ASM had a positive effect on the occurrence and outbreak of N. lugens. First, the first appearance date of N.lugens was consistent with seasonal advances of the northernmost location of the ASM, and the ASM provided the dynamic condition for the northward migration of N. lugens. Second, outbreak of N. lugens occurred in the area under the control of the ASM, and the ASM provided the survival condition for the population of N. lugens. Third, the population was positively related to the northernmost location of the ASM, θ_E(850 hPa) and wind speed(850 hPa).Particularly, the stronger southwest wind caused the date of the first, peak and last catches of N. lugens to turn up earlier than in the extremely years.     

基于MODIS的北京地区一次霾过程的能见度反演

利用MODIS_L1B数据,结合AERONET（AErosol RObotic NETwork）地面观测与反演的AOD（Aerosol Optical Depth）数据、北京市自动气象站网的能见度观测数据和北京市道面交通气象监测网的能见度观测数据,选取2012年3月6—11日期间发生在北京市的一次重大霾天气过程作为典型个例,反演了全过程的AOD和能见度变化,分析了两者之间的关系。结果表明：1）由MODIS遥感数据反演的AOD值与地面实测AOD值变化趋势均呈“单峰型”,但由于存在观测时间的偏差,总体上反演值高于实测值;2）利用AOD反演值得到的能见度值与实际能见度观测值基本吻合,两者的时空变化趋势基本一致,两者之间的相关系数大于0.6（P<0.01）,符合此次霾过程的实际发生特征。     

A Study of the Qianyanzhou Mode in a Subtropical Red Soil Hilly Region of China

Qianyanzhou is located in the heart of Jitai Basin in Guanxi town, the county seat of Taihe county in Jiangxi province. Qianyanzhou has a subtropical humid climate and exemplifies the geographic and geomorphologic characteristics of red soil hilly regions in southern China. In the early 1980s, to control soil and water loss and problems with grain yields, Qianyanzhou’s researchers proposed an innovative, comprehensive stereoscopic agriculture development mode known as the “Qianyanzhou mode”. This mode included a forest-livestock-food ecosystem, a forest-fruit-economy ecosystem, and a land-water compound stereoscopic system, all located within a watershed. In the Qianyanzhou mode, soil and water loss were completely controlled, thereby promoting environmental conservation and economic development. The state and the society as a whole supported this mode thanks to its far-reaching social impact. In the 21^st century, given new societal concerns and continuing economic development, Qianyanzhou mode has been restructured as two ecosystems of forest-fowl and planting-raising circular economies at landscape level, based on an increase in vegetation coverage from 4.3% to more than 80%. These improved modes can significantly enhance the ecosystem, reduce poverty, and to promote the construction of local ecological civilization. This study introduces the Qianyanzhou mode and summarizes its characteristics in different phases. We hope that the information in this study supports improvements to and promotion of the Qianyanzhou mode. We believe the Qianyanzhou mode can play an important role in efforts to modify the agriculture industrial structure, alleviate poverty, and construct ecological civilization.     

大菱鲆周期蛋白依赖激酶基因cdk1、cdk6克隆及表达分析

通过同源克隆以及5′/3′RACE的方法扩增得到大菱鲆(Scophthalmus maximus)细胞周期蛋白依赖激酶基因cdk1和cdk6的全长c DNA序列,在m RNA水平上分析了它们组织表达特征,并对比分析了静水压处理对其胚胎期表达的影响。结果显示,cdk1基因全长c DNA序列为1281 bp(Gen Bank登录号:KP339306),编码区为912 bp;cdk6基因c DNA全长1400 bp(Gen Bank登录号:KT186374),编码区长度为978 bp。组织RT-PCR分析表明,cdk1基因表达具有广泛性,在性腺、肾脏等生长发育较快的组织中表达量较高;cdk6基因也在多个组织中表达,在性腺中表达量最高。通过Real time RT-PCR检测基因在胚胎中的表达水平发现,静水压处理组cdk1、cdk6在胚胎发育中,总体变化趋势与对照组类似。大菱鲆胚胎对照组中cdk1在原肠期以前相对神经胚期及以后时期表达量较高,静水压处理组基因表达变化与对照组趋势相同;对照组中cdk6在原肠期出现表达高峰,但静水压处理组在原肠期表达量相对较低。静水压处理对cdk1和cdk6的表达量的影响不同,这可能与基因还有除调控细胞周期的其他功能有关。为解析这两个基因在大菱鲆胚胎发育中的作用及其机制提供了参考。     

希尔伯特-黄变换在微弱被动瞬态鱼声信号中的检测

为了在海洋环境中准确获取鱼类在摄食、产卵和争斗过程中发出的短促、瞬时的信号,采用希尔伯特-黄变换算法实现微弱被动瞬态鱼声信号的检测。该算法首先将瞬态鱼声信号实现固有模态信号的分解,其次将经验值高阶阶数的固有模态信号求和重构即可实现信号能量幅度检测;在固有模态信号的分解的基础上,计算求和重构信号的希尔伯特能量谱,即可实现瞬时能量密度级的检测。通过不同信噪比和检测器的比较研究,结果表明基于希尔伯特-黄变换算法的两种检测方法能有效提高微弱被动瞬态鱼声信号的检测性能。