Quantitative measurements on the paleo-weathering intensity of the loess-soil sequences and implication on paleomonsoon

The loess-soil sequences in northern China provide a near continuous record of Quaternary paleoclimate. The pedogenetic intensity of the sequences is closely linked with the variations of the East Asian summer monsoon. In this study, 2181 samples from the Changwu and Xifeng loess sections are analyzed and two high-resolution paleo-weathering timeseries of the last 1.2 Ma are generated, using the ratio of CBD extractable free Fe₂O₃ (FeD) versus the total iron (FeT). This new index is compared with micromorphological features, low-frequency magnetic susceptibility, frequency-dependent magnetic susceptibility, and the Rb/Sr ratio^[5,6]. The results suggest that the FeD/FeT ratio is able to better reflect the degree of soil development. Since the chemical weathering of loess in the Loess Plateau region mainly depends upon the summer precipitation and temperature under modern climate condition, which are closely associated with strength of summer monsoon, and the chemical weathering intensity of loess primarily reflects the variations of the summer monsoon circulation.     

The Athens earthquake (7 September 1999): intensity distribution and controlling factors

The Athens earthquake, M_s=5.9, that occurred on 7th September 1999 with epicenter located at the southern flank of Mount Parnitha (Greece, Attiki) according to instrumental data, is attributed to the reactivation of an ESE–WNW south- dipping fault without surficial expression. The earthquake caused a large number of casualties and extensive damage within an extended area. Damage displayed significant differentiation from place to place, as well as a peculiar geographic distribution. Based on geological, tectonic and morphological characteristics of the affected area and on the elaboration of damage recordings for intensity evaluation, it can be safely suggested that intensity distribution was the result of the combination of a number of parameters both on macro and microscale. On the macroscale, the parameters are the strike of the seismogenic fault, seismic wave directivity effects and to an old NNE–SSW tectonic structure, and they are also responsible for the maximum intensity arrangement in two perpendicular directions ESE–WNW and NNE–SSW. On the microscale, site foundation formations, old tectonic structures buried under recent formations and morphology are the parameters that differentiated intensities within the affected area.     

热带和热带外海表温度异常与低空环流特征比较

利用旋转主分量方法（ＲＰＣ），在对西太平洋和印度洋１９８０年１月至１９８８年９月共１０５个月的月平均海表温度（ＳＳＴ）进行分析的基础上，提取热带模及高纬模两种ＳＳＴ异常（ＳＳＴＡ）分布。再通过分析同期８５０ｈＰａ，各气象要素在该两模上的投影，比较低层大气与不同纬度上ＳＳＴＡ相联系的异常特征。结果表明，无论是热带还是热带外地区，暖性ＳＳＴＡ上空均有正的水汽异常及平均流场对月平均水汽输送的异常辐合。两地区ＳＳＴＡ上空８５０ｈＰａ月平均异常的最重要差异表现在流场、高度场及温度场上。热带正ＳＳＴＡ上方８５０ｈＰａ位势高度及温度均为负距平，流场呈Ｇｉｌｌ型的气旋式异常环流。热带外正ＳＳＴＡ上方８５０ｈＰａ高度及温度均为正距平，流场则呈反气旋式异常环流。分析表明，高纬度的这种异常特征主要是由于中高纬度大气的地转性和斜压性较强所致。     

近海热带气旋迅速加强的气候特征

根据我国近海热带气旋发生、发展的气候特点，规定12小时热带气旋中心附近最大风速增值≥10 m/s为迅速加强。通过1949～1990年近海发生迅速加强的84个热带气旋个例分析，阐述了迅速加强时段的时间分布、地区分布及迅速加强前后气象要素变化的气候特征。     

岩石蠕变破坏实验研究及其对地震预报的意义

通过对不同温度和围压条件下济南辉长岩的蠕变破坏实验结果和声发射特征分析,本文提出以岩石蠕变破坏应变做为岩石蠕变破坏判据。建立了岩石蠕变破坏应变的经验关系式。依据实验结果得到相应的济南辉长岩蠕变破坏应变参数,进一步探讨了预报岩石蠕变破坏和地震的方法     

A Coupled General Circulation Model for the Tropical Pacific Ocean and Global Atmosphere

On the basis of Zeng’s theoretical design, a coupled general circulation model (CGCM) is developed with its characteristics different from other CGCMs such as the unified vertical coordinates and subtraction of the standard stratification for both atmosphere and ocean, available energy consideration, and so on. The oceanic component is a free surface tropical Pacific Ocean GCM between 30oN and 30oS with horizontal grid spacing of 1o in latitude and 2o in longitude, and with 14 vertical layers. The atmospheric component it a global GCM with low-resolution of 4o in latitude and 5o in longitude, and two layers or equal man in the vertical between the surface and 200 hPa. The atmospheric GCM includes comprehensive physical processes. The coupled model is subjected to seasonally-varying cycle. Several coupling experiments, ranging from straight forward coupling without flux correction to one with flux correction, and to so-called predictor-corrector monthly coupling (PCMC), are conducted to show the existence and final controlling of the climate drift in the coupled system. After removing the climate drift with the PCMC scheme, the coupled model is integrated for more than twenty years. The results show reasonable simulations of the annual mean and its seasonal cycle of the atmospheric and oceanic circulation. The model also produces the coherent interannual variations of the climate system, manifesting the observed El Ni?o / Southern Oscillation (ENSO).     

南亚高压强度与邻近地区垂直速度的相互依赖关系

利用ERA-Interim 1979—2018年6—8月的再分析资料,通过相关分析、信息流、合成分析等方法研究了南亚高压强度与其邻近地区垂直速度的相互依赖关系.结果表明：南亚高压在上对流层-下平流层区域具有上冷下暖的热力结构,冷、暖中心分别在70 hPa和250 hPa,以这两层的温度异常建立的温差指数可以反映南亚高压的强度.在不同时间尺度上,南亚高压强度与其邻近地区垂直速度的相互依赖关系是不同的.在月时间尺度上,南亚高压强度通过动力作用影响邻近地区的垂直速度,南亚高压增强（减弱）时,其东部地区的上升运动和西部地区的下沉运动同步增强（减弱）;在日时间尺度上,南亚高压中部的垂直速度通过热力强迫影响南亚高压强度,南亚高压中部地区上升运动增强（减弱）时,南亚高压增强（减弱）且位置偏西（偏东）.     

Englacial vs lacustrine origin of volcanic table mountains: evidence from iceland

Detailed facies analysis of hyaloclastites and associated lavas from eight table mountains and similar "hyaloclastite volcanoes" in the Icelandic rift zone contradict a rapid and continuous, "monogenetic", entirely subglacial evolution of most volcanoes studied. The majority of the exposed hyaloclastite deposits formed in large, stable lakes as indicated by widespread, up to 300-m-thick, continuous sections of deep water, shallow water and emergent facies. Salient features include extensively layered or bedded successions comprising mainly debris flow deposits, turbidites, base surge and fallout deposits consisting of texturally and compositionally variable, slightly altered hyaloclastites, as well as sheet and pillow lavas. In contrast, chaotic assemblages of coarser-grained, more poorly sorted and more strongly palagonitized hyaloclastite tuffs and breccias, as well as scoria and lava are interpreted to have formed under sub- or englacial conditions in small, chimney-like ice cavities or ice-bound lakes. Irregularly shaped and erratically arranged hyaloclastite bodies produced at variable water levels appear to have resulted mainly from rapid changes of the eruptive environment due to repeated build-up and drainage of ice-bound lakes as well as the restricted space between the ice walls. We distinguish a "deep water" facies formed during high water levels of the lake, a hydroclastic shallow water and emergent facies (leakage of the lake or growth of the volcano above the water surface). Our model implies the temporary existence of large, stable lakes in Iceland probably formed by climatically induced ice melting. The highly complex edifices of many table mountains and similar volcanoes were constructed during several eruptive periods in changing environments characterized by contrasting volcanic and sedimentary processes. Received: 10 June 1997 / Accepted: 28 July 1998     

东海近海热带气旋及天气数值预报系统

以ＭＭ４模式为框架,研制并建立了东海近海热带气旋及天气数值预报系统,将对热带气旋的预报和一般天气的预报统一在一个模式中,并实现了业务自动化控制,自１９９４年台风季节起投入了业务试验和准业务的运行。结果表明：该系统对东海近海热带气旋路径、风场、降水及江淮梅雨降水具有较好的预报能力