Numerical study of rapid cyclogenesis over sea

A five-layer primitive equation model was used in the study of rapid cyclogenesis over sea. The numerical simulations show that'the Tibetan Plateau, large-scale baroclinicity and heat flux from the sea surface are the three important agents to produce cyclonic vorticity along the east coast of China. The diagnostic computation of a 24 h control simulation indicates that the nonlinear vorticity advec-tion, baroclinicity and diabatic heating are also responsible for the development of the extratropical cyclones over seas.

Applications of Bias-removed Ensemble Mean in the Gale Forecasts over the Yellow Sea and the Bohai Sea

Based on the daily sea surface wind field prediction data of Japan Meteorological Agency(JMA) forecast model,National Centers for Environmental Prediction(NCEP GFS) model and U.S.Navy Operational Global Atmospheric Prediction System(NOGAPS) model at 12:00 UTC from June 28 to August 10 in 2009,the bias-removed ensemble mean(BRE) was used to do the forecast test on the sea surface wind fields,and the root-mean-square error(RMSE) was used to test and evaluate the forecast results.The results showed that the BRE considerably reduced the RMSEs of 24 and 48 h sea surface wind field forecasts,and the forecast skill was superior to that of the single model forecast.The RMSE decreases in the south of central Bohai Sea and the middle of the Yellow Sea were the most obvious.In addition,the BRE forecast improved evidently the forecast skill of the gale process which occurred during July 13-14 and August 7 in 2009.The forecast accuracy of the wind speed and the gale location was also improved.

The characteristics of sea fog with different airflow over the Huanghai Sea in boreal spring

Using the observations from ICOADS datasets and contemporaneous NCEP/NCAR reanalysis datasets during 1960-2002,the study classifies the airflows in favor of sea fog over the Huanghai （Yellow） Sea in boreal spring （April-May） with the method of trajectory analysis,and analyzes the changes of proportions of warm and cold sea fogs along different paths of airflow.According to the heat balance equation,we investigate the relationships between the marine meteorological conditions and the proportion of warm and cold sea fog along different airflow paths.The major results are summarized as follows.（1） Sea fogs over the Huanghai Sea in spring are not only warm fog but also cold fog.The proportion of warm fog only accounts for 44% in April,while increases as high as 57% in May.（2） Four primary airflow paths leading to spring sea fog are identified.They are originated from the northwest,east,southeast and southwest of the Huanghai Sea,respectively.The occurrence ratios of the warm sea fog along the east and southeast airflow paths are high of 55% and 70%,while these along the southwest and northwest airflow paths are merely 17.9% and 50%.（3） The key physical processes governing the warm/cold sea fog are heat advection transport,longwave radiation cooling at fog top,solar shortwave warming and latent heat flux between airsea interfaces.（4） The characteristics of sea fog along the four airflow paths relate closely to the conditions of water vapor advection,and the vertical distribution of relative humidity.

INVERSION OF TEMPERATURE FROM AMSU-A AND ITS APPLICATION ON WARM-CORE OF TROPICAL DEPRESSION OVER THE SOUTH CHINA SEA

The linear regression and horizontally stepwise correction are conducted on the observational data from AMSU-A L1 B of NOAA polar orbit satellite to invert a 40-layers(from 1,000 h Pa to 0.1 h Pa) dataset of atmospheric temperature with a horizontal resolution of 0.5°×0.5° after the correction of satellite antenna pattern and limb adjustment. Case study shows that the inversion data of temperature can reveal the detail structure of warm core in tropical cyclone. We choose two categories of tropical depressions(TDs) over the South China Sea, including the non-developing TDs and developing TDs. Both of them are developed downward from the middle and upper level to the lower level. Comparison between the evolutions of warm core in the two categories of TDs indicates that the warm core is developed downward from the middle and upper troposphere to the sea surface in all the downward-developing TDs. The difference is that in the group of further developing TDs, the warm core in the upper troposphere is intensified suddenly when it is extending to the sea surface. The warm core in the upper and lower troposphere is strengthened in a meantime. But the similar feature is not observed in the non-developing TDs. Then it may be helpful to judge the TD development by monitoring the change in its warm-core structure.

Atmospheric Circulations and Sea Surface Temperatures Related to the convection over the western Pacific Warm Pool on the Interannual Scale

The difference is examined in atmospheric circulation and Sea Surface Temperatures (SSTs) in the trop-ics and subtropics between weak and strong convection over the tropical western Pacific warm pool (signified as WPWP). The WPWP is chosen as the region (110–160°E, 10–20°N), where the Outgoing Longwave Radiation (OLR) shows a great year-to-year variance. A composite study was carried out to examine the differences in atmospheric circulation and SSTs between weak and strong convection over WPWP. First, NCEP/NCAR re-analysis data and satellite-observed OLR data are used to examine the differences. ERA data, in which the OLR data are calculated, are then used for re-examination. The composite results show that the differences are remarkably similar in these two sets of data. The difference in circulations between weak and strong convection over WPWP is significantly associated with westward extension of the North Pacific subtropical anticyclone and stronger westerlies at the northwestern edge of the subtropical anticyclone. It also corresponds with the significant easterly anomaly and the descent anomaly in situ, i.e., over the WPWP. The most prominent characteristics of the difference of SSTs between weak and strong convection over the WPWP are the significant positive SST anomalies in the Indian Ocean, the Bay of Bengal and the South China Sea. In WPWP, however, there are only weak negative SST anomalies. Thus, the anomaly of OLR over WPWP is weakly associated with the SST anomalies in situ, while closely associated with the SST anomalies west of WPWP. Key words Convection over the western Pacific warm pool - Northwest Pacific subtropical high - Sea surface temperatures This study was supported by the “ National Key Programme for Developing Basic Sciences” G1998040900 Part 1.

中国当代文学作品海外传播的文化基因——以徐则臣《北上》为例

作为从小生长在水边的当代作家,徐则臣自20世纪末就开始创作有关运河的作品。他用20余年的时间欣赏运河、感受运河,最终凭借《北上》这部作品获得第十届茅盾文学奖,成为“70后”首位茅盾文学奖得主。新时代下,中国当代文学已进入全球化语境,受世界瞩目。随着中国文学“走出去”的步伐逐渐加快,中国文学作品中的文化基因是什么,中国当代文学作品海外传播中的文化使命是什么,都值得我们深思。《北上》是徐则臣创作的一部文学作品,其以程裕祯对文化分层理论为依据,探索中国当代文学作品中的文化基因,并进一步思考中国当代文学作品海外传播中文化基因的使命,力图为中国文学作品海外传播提供思路。

2022年5月江西省降水量气候趋势预测评估分析

选用地面观测、NCEP再分析等资料,应用青藏高原积雪面积距平指数和大气环流指数,对比实况与气候动力模式结果,对2022年5月江西省降水量气候预测进行评估,并分析预测信号及其应用情况。结果表明:2022年5月气候动力模式“江西省南部降水偏多”的总体降水气候特征预测较为准确,且“江西省存在降水集中期,部分地区有洪涝发生”的预测与实况相一致,5月降水过程的预报基本准确,但江西省北部以及中部地区的旱情预报等级偏小。前期预测综合了拉尼娜事件、前一年冬季冬青藏高原积雪异常偏多和印度洋海温变化等多个预测信号对2022年5月江西省降水量气候趋势的影响,但低估了拉尼娜事件对该月江西省降水的影响,高估了高原积雪异常偏多对江西北部降水的影响,导致出现预测偏差。

A DIAGNOSTIC ANALYSIS OF THE RELATIONSHIPBETWEEN THE FLUXES AND METEOROLOGICAL ELEMENTS OVER TROPICAL WESTERN PACIFIC

Through the use of the hourly wind, air temperature and humidity, sea surface temperature data measured on board the observing vessel Moana Wave and buoy in the warm pool of western Pacific during the IOP of TOGA COARE, we compute the fluxes over sea surface and analyze the characteristics of the variation of the latent heat flux with sea surface temperature. During weak rather than strong wind periods, a maximum value of latent heat flux appears at some points of SST. which is caused mainly by the variations of wind, then by the humidity difference between air and sea, and the transfer coefficient with SST. Using correlation analysis, we also analyze the relationship between the fluxes and meteorological elements during weak wind periods, westerly wind burst periods, and convective disturbed periods etc. The main conclusions are that the latent heat flux is mainly determined by wind, sensible heat flux by the potential temperature difference between air and sea. and the momentum flux by wind. The precipitation affects the sensible heat flux through the potential temperature difference and wind.

20世纪70年代中国香港报刊对西沙事态的反应——以《明报月刊》为考察中心

1974年1月,西沙海战爆发后,中国香港报刊积极报道与战事相关的内容,对中国香港社会的维权动态以及南海诸岛史地知识亦多有着墨,但很少深入探讨中国南海主权。相对而言,《明报月刊》则刊登了一系列由中国香港、中国台湾学者和海外华人学者所撰写的学术维权文章,为中国南海诸岛主权的论证提供了历史和法理依据。

Synthetic tidal parameters for gravity over China and its neighbor area

The synthetic tidal parameters with high spatial resolution for gravity over China and its neighbor area are constructed with Earth＇s tidal model and ocean tide loading calculated using TPXO7 global ocean tide model as well as tidal data over China seas. The comparison between synthetic parameters and ones observed by spring gravimeters at some seismic network stations and Hong Kong station and one observed by super-conducting gravimeter at Wuhan station shows that the average differences in amplitude factors and phases are smaller than 0.005 and 0.5° respectively; and that the discrepancies between observational and synthetic parameters are dependent on gravimetric technique in that the synthetic parameters are in well agreement with the superconducting gravimetric observations. This also indicates that the synthetic result is a good estimation for tidal gravity, and the numerical results in the present paper not only can provide ground and space gravimetry such as absolute gravimetry with correction model of tidal gravity, but also provide effective tidal parameters over areas where no observation is carried out.

潮汐与广州园池

从谢兰生《常惺惺斋日记》及格雷夫人的家信中关于潮汐与游园的记载出发,着重探究潮汐与广州园池之间的关系,分析广州历代园林沿水系分布的七条主要线索,深入解读历史文献和图像中的内城喻园、花地馥荫园、河南潘家花园、荔枝湾海山仙馆、西关长寿寺花园和伍家花园等代表性园林因应潮汐而出现的双池与多池、窦口、池间堤、堤边树、垂直池壁与拦河、高架廊道和池上楼馆等现象,以及其中蕴涵的海山想象。认为潮汐对广州园池的择址、布局、立意、理景、造屋、栽植和游赏都产生了深刻的影响,并由此形成了依水筑园、跨波构基、高树深池、风廊水殿和真海仙山等“惟岭南园林得之”的重要特色。

以“包容性绿色发展”引领中国话语海外传播

新时代的中国方案和中国力量、中国理论和中国实践,把包容性绿色发展推到人类走向共同体的“命运性选择”的高度,为世界包容性绿色发展作出了重大贡献。以“包容性绿色发展”概念为引领促进中国话语的海外传播,是响应习近平“讲清楚中国”的号召所做的“走出去”的工作。“包容性绿色发展”作为标识性概念的巨大融通性,赋予其超越西方标识性对抗话语的时代话语使命,突显引领中国话语“走出去”的可行性和优越性。

冬季华南降水年际变化的环流特征及对前期海面温度异常响应

利用我国160站降水观测资料、NCEP/NCAR再分析资料以及英国哈德莱中心的海表面温度资料,分析了华南冬季(12月至次年2月)降水年际变化的大气环流特征以及对前期海面温度(Sea Surface Temperature,SST)异常的响应。结果表明,东亚高空急流异常偏南(偏北),东亚大槽减弱(增强),天气瞬变扰动和南支槽加强(减弱),来自孟加拉湾和南海的西南风在华南形成异常辐合(辐散),从而有利于该地区降水异常偏多(偏少)。ENSO型SST异常不能完全解释华南降水异常年南支槽和低层环流特征,进一步研究表明,导致华南降水异常的南支槽和低层风场变化与热带印度洋和赤道西太平洋SST异常关系更为密切。由前期热带印度洋和赤道西太平洋构建的SST指数和华南冬季降水相关达到0.44,两者相关系数在SST指数超前1个月时达到最大,对华南冬季降水具有一定潜在预报意义。

北极海冰融化与东亚春季降水量的联系

本文利用NCEP/NCAR等再分析资料和CAM5.4数值模式,研究了春季北极海冰融化面积对东亚降水量的影响及其可能的物理机制。观测和数值模拟结果均显示,与春季海冰融化相关的东亚地区降水量呈现明显增加的趋势,且异常中心位于中国南部-日本地区。500 hPa位势高度场表现为“-+-+”型波列结构,其中乌拉尔山和日本及其附近海洋上空为异常高压脊区,欧洲西部和贝加尔湖地区则为异常高空槽所控制。高融化面积年常伴随着极地西风急流增强,中纬度纬向西风减弱,有利于乌拉尔山地区反气旋性环流异常的维持和增强,进而触发乌拉尔山地区到西北太平洋地区的异常波列,引起贝加尔湖地区位势高度降低,东亚槽加深,受异常偏北气流的影响,南下冷空气活动频繁。日本及其附近的海洋上空位势高度增加,在异常偏东南气流的作用下,将西北太平洋地区的暖湿空气带到东亚地区。中国南部地区出现西风异常,引起东亚副热带急流增强,配合低空辐合高空辐散的大气异常环流,局地对流增强,导致东亚地区春季降水量增加。

海洋划界国际司法实践中判断岛屿效力的原则

国际司法实践中发展出一系列判断岛屿效力的原则,这些原则不仅包括公平原则和陆地统领海洋原则这样的基本原则,也包括条约必须遵守原则、相同事物相同对待原则、不得重塑地理原则、比例原则、不侵占原则这样的具体原则。这些具体原则是基本原则的具体化,为岛屿效力的判断提供了一定的参照。然而,这些原则并不能涵盖判断岛屿效力的全部因素,在具体案件中需要考虑哪个或哪几个原则是不确定的,加上这些原则本身具有很大的主观性,因此,岛屿效力的判断仍具不确定性。

南黄海盆地二叠系高-过成熟烃源岩的生物标志化合物特征及其地质意义

南黄海盆地二叠系烃源岩的生烃层系多、热演化程度高、沉积环境变化大,前人极少从生物标志化合物的角度探讨烃源岩的差异。本文通过对CSDP-2井二叠系16个成熟-过成熟烃源岩样品进行有机地球化学分析,剖析了四套烃源岩的饱和烃、芳香烃馏分中生物标志化合物的组成、演化规律及地质意义。结果表明,二叠系不同层系烃源岩的甾烷系列、三芳甾烷系列、烷基二苯并噻吩系列化合物和β-胡萝卜烷的相对丰度具有显著差异,据此可将其分为栖霞组下段和龙潭组-大隆组泥岩、栖霞组上段和孤峰组硅质岩、孤峰组硅质泥岩3类烃源岩。研究显示,栖霞组下段和龙潭组-大隆组泥岩烃源岩沉积于淡水氧化或微咸水贫氧环境,有机质来源于浮游生物和陆生高等植物;栖霞组上段-孤峰组烃源岩沉积于还原咸水或静水硫化环境,其中硅质岩烃源岩的有机质来源于浮游生物和硅藻,硅质泥岩烃源岩的有机质来源于浮游生物、硅藻和陆生高等植物。此外,甲基菲指数、烷基二苯并噻吩参数(4-MDBT/DBT、MDBI、4,6-/1,4-DMDBT)可作为上二叠统烃源岩的成熟度指标,但不能作为中—下二叠统烃源岩的成熟度指标。

非法移民遣返措施的困境和完善

随着我国对外开放水平的提高,非法移民问题愈演愈烈,不可忽视。非法移民问题对我国社会治理水平提出了较高的要求,因此不得不重新审视作为非法移民主要处理措施的遣返制度。目前,我国非法移民遣返虽然取得了一定的成效,但依然存在着相关法律明确性欠缺、遣返前置性措施不完善、遣返措施作用未得到充分发挥等问题。改革开放以来,我国遣返制度在维护国家安全和出入境管理秩序方面做出了巨大贡献。为更加充分地发挥遣返制度在管控非法移民中的作用,提高非法移民的治理工作质量,必须从健全遣返法律法规、推进国际合作、思考遣返措施在反贪中的作用等方面建设健全我国现存的非法移民遣返制度,从而为推进我国社会主义建设创造更便利的条件。

基于海杂波修正的OTHR空中目标RCS估计

天波超视距雷达工作在时变的电离层传输状态下,通过回波能量难以对空中目标的雷达散射截面积(RCS)进行有效估计。为此,提出了一种基于海杂波修正的目标RCS估计方法,建立了RCS估计卡尔曼滤波模型和RCS仿真数据辅助模型。通过两型民航目标的仿真和实测数据验证了所提模型的有效性,其在不同时段、雷达工作状态和电离层传输条件下,实现了对目标RCS和电离层损耗的稳健估计,并利用目标电磁仿真数据进一步辅助提高了对已知类型目标的估计效率和准确性。

海面与海岸陆面风速廓线特征

利用位于江苏海岸陆地的两座测风塔以及福建海面的一座测风塔气象要素资料,分析了这两种下垫面风速、湍流等要素的日变化规律及廓线特征,探讨了这两种不同下垫面特征导致的风力特征差异。结果表明:海岸陆面日最大风速出现时间较内陆滞后,最小风速出现时间与内陆相差不大,风速日变化位相随高度滞后,日振幅随高度减小,冬季70 m高度风速日变化特征与10 m高度风速日变化特征相反,夜间大于白天,说明冬季的过渡层转换高度低于夏季;海面风速的日变化位相、日振幅等特征随高度变化很小。两种下垫面的风廓线用对数律、指数律拟合的效果相当,海岸陆面的风廓线指数呈现的规律为离岸风组大于向岸风组,冬季大于夏季;海面风廓线指数呈现的规律则是向岸风组大于离岸风组,夏季大于冬季。

利用循环3DVAR改进黄海海雾数值模拟初始场Ⅰ:WRF数值试验

以如何提高黄海海雾数值模拟初始场质量为研究目的，利用WRF模式及其先进的3DVAR同化模块，设计并构建了循环3DVAR同化方案。以2006年3月6～8日的1次大范围黄海海雾过程为研究对象，利用该同化方案进行了一系列WRF数值模拟对比试验。模拟结果显示，循环3DVAR同化方案能有效改进黄海海雾数值模拟初始场质量，主要体现在增加低层大气温度层结构的稳定性与改变大气边界层下层的风场结构，从而导致海雾的模拟结果显著改善。研究结果表明进行海雾数值模拟时，必须高度重视其初始场质量。