Benthic nutrient recycling in shallow coastal waters of the Bohai Sea

Sediment-water fluxes of N and P species in the Bohai Sea were investigated in September-October 1998 and April-May 1999. The benthic fluxes of nutrient species were determined by incubating sediment core samples with bottom seawater bubbled with air or nitrogen. NO^-2,NH4, dissolved organic nitrogen (DON) and phosphorus (DOP), total dissolved nitrogen (TDN) and phosphorus (TDP), and PO4^3- showed a net exchange flux from seawater to sediment, while NO^-3, dissolved inorganic nitrogen (DIN) and SiO3^2- were released from sediment to seawater in the Bohai Sea. Sediment-water nutrient exchange increases DIN and reduces the phosphorus load in the Bohai Sea. The release of silicate from sediment to overlying seawater reduces potential silicate limitation of primary production resulted from decrease of riverine discharge.The exchange flux of nutrients showed no obvious seasonal variation. The present study showed that the concentrations and composition of nutrients in the water column were affected by suspended sediment, and that not all the exchangeable phosphate in sediment could be released via sediment resuspension.     

山东半岛冷流强降雪和非冷流强降雪的对比分析

利用1981—2000年常规气象观测和NCEP/NCAR再分析资料,采用合成分析和动力诊断分析方法,对冷流强降雪与非冷流强降雪的空间分布、大气环流、水汽输送、稳定度和垂直运动进行对比分析。结果表明：冷流强降雪是发生在槽后西北气流里的中小尺度不稳定降雪,非冷流强降雪是发生在槽前西南气流中大尺度稳定性降雪。冷流强降雪具有明显的地方性特点,是强冷空气对下垫面物理状态强迫响应的结果。提出强冷空气与渤海暖水面相互作用产生的大气边界层不稳定是产生冷流降雪的本质,在这种边界层不稳定层结中发生的降雪是冷流降雪的概念。     

Soil and vegetation seasonal changes in the grazing Andean Mountain grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna（Vicugna vicugna） and alpaca（Lama pacos）. The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined： total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.     

Identification of Fucans from Four Species of Sea Cucumber by High Temperature ~1H NMR

Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei（Pg） from Indo-Pacific, Holothuria vagabunda（Hv） from Norwegian Coast, Stichopus tremulu（St） from Western Indian Ocean, and Isostichopus badionotu（Ib） from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans（SC-Fucs）. The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer（NMR） and room temperature 13 C NMR. The results indicated that Fuc-Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc-Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc-St from the frigid zone and Fuc-Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.     

物联网常识

正物联网(TheInternetofthings)的概念是在1999年提出的,它的定义很简单:把所有物品通过射频识别(RFID)、红外感应器、全球定位系统、激光扫描器等信息传感设备与互联网连接起来,进行信息交换和通讯,实现智能化识别、定位、跟踪、监控和管理。物联网把新一代IT技术充分运用在各行各业之中,具体地说,就是把感应器嵌入和装备到电网、铁路、桥梁、隧道、公路、建筑、大坝、油气管道等各种物体中,然后将"物联网"与现有的互联网整合起来,实现人类社会与物理系统的整合,在这个整合的网络当中,存在能力超级强大的中心计算     

Effect of Decadal Changes in Air-Sea Interaction on the Climate Mean State over the Tropical Pacific

Collaboration of interannual variabilities and the climate mean state determines the type of E1 Nifio. Recent studies highlight the impact of a La Nifia-like mean state change, which acts to suppress the convection and low-level convergence over the central Pacific, on the predominance of central Pacific （CP） E1 Nifio in the most recent decade. However, how interannual variabilities affect the climate mean state has been less thoroughly investigated. Using a linear shallow-water model, the ef- fect of decadal changes of air-sea interaction on the two types of El Nifio and the climate mean state over the tropical Pacific is examined. It is demonstrated that the predominance of the eastem Pacific （EP） and CP E1 Nino is dominated mainly by relationships between anomalous wind stresses and sea surface temperature （SST）. Furthermore, changes between air-sea interactions from 1980-98 to 1999-2011 prompted the generation of the La Ninalike pattern, which is similar to the background change in the most recent decade.     

两类La Nia季节演变过程的海气耦合特征对比

利用1951—2010年逐月的HadISST海表温度资料、SODA次表层海温资料和NCEP/NCAR再分析资料等,对比分析了东太平洋(EP型)La Nia和中太平洋(CP型)La Nia的海气耦合特征在季节演变过程中的差异。EP La Nia海表温度异常中心在发展年夏季出现于南美沿岸,随后向西移动,盛期最大海表温度异常中心位于赤道东太平洋,而CP La Nia海温异常中心少动,基本维持在160°W附近,其强度更强,持续时间更长。受海温分布形态影响,热带大气对两类La Nia的响应非常不同,成熟期间CP型在中太平洋偏旱的强度和范围比EP型大,且略偏西。发展年夏、秋季,北半球位势高度响应较弱;冬季,负PNA位相易伴随两类La Nia出现,但异常活动中心的位置和强度不同,在北大西洋其大气响应几乎相反,这些差异会引起显著不同的区域气候异常。     

Intraseasonal Oscillation of the South China Sea Summer Monsoon and Its Influence on Regionally Persistent Heavy Rain over Southern China

The intraseasonal oscillation（ISO） in the South China Sea summer monsoon（SCSSM） and its influence on regionally persistent heavy rain（RPHR） over southern China are examined by using satelhte outgoing long wave radiation,NCEP/NCAR reanalysis,and gridded rainfall station data in China from 1981 to 2010.The most important feature of the ISO in SCSSM,contributing to the modulation of RPHR,is found to be the fluctuation in the western Pacific subtropical high（WPSH）,along with a close link to the Madden-Julian oscillation（MJO）.Southern China is divided into three regions by using rotated empirical orthogonal functions（REOFs）for intraseasonal rainfall,where the incidence rate of RPHR is closely linked to the intraseasonal variation in rainfall.It is found that SCSSM ISOs are the key systems controlling the intraseasonal variability in rainfall and can be described by the leading pair of empirical orthogonal functions（EOFs） for the 850-hPa zonal wind over the SCS and southern China.Composite analyses based on the principal components（PCs） of the EOFs indicate that the ISO process in SCSSM exhibits as the east-west oscillation of the WPSH,which is coupled with the northward-propagating MJO,creating alternating dry and wet phases over southern China with a period of 40 days.The wet phases provide stable and lasting circulation conditions that promote RPHR.However,differences in the ISO structures can be found when RPHR occurs in regions where the WPSH assumes different meridional positions.Further examination of the meridional-phase structure suggests an important role of northward-propagating ISO and regional air-sea interaction in the ISO process in SCSSM.     

中国西部地区气温与太平洋海温的关系

利用1961~1990年我国西部(110 E以西)155个测站的地面月平均气温和同期太平洋地区月平均海温资料和经验正交函数(EOF)展开方法,研究了中国西部地区各个季节的气温距平时空分布规律以及西部地区气温距平与太平洋海温异常之间的相互联系。结果发现:利用EOF展开得到的特征向量和时间系数能够较好地反映西部地区实际气温异常的时空分布特征。El Nino和La Nina年西部气温距平分布(冬季除外)呈现基本相反的状况,即在El Nino年气温偏暖(冷)的区域,在La Nina年则是气温偏冷(暖)的区域。各季节西部地区的气温变化与太平洋海温异常存在着相互影响和作用。     

质子交换膜燃料电池参数正交设计的数值研究

以影响质子交换膜燃料电池（PEMFC）性能的12个参数为研究对象,以给定电压条件下的输出电流为考核目标,通过正交设计方法与数值模拟相结合,采用模糊熵权法,将多指标转化为单指标。研究结果表明：阴极传递系数、阴极交换电流密度、氧气参考浓度、氧气在参考状态下的扩散系数是影响电池性能的主要参数,阴极传递系数与氧气在参考状态下的扩散系数、阴极交换电流密度与氧气参考浓度、阴极交换电流密度与氧气在参考状态下的扩散系数、氧气参考浓度与氧气在参考状态下的扩散系数间有很显著的交互作用。