夏季长江中下游和华南两类雨型的环流特征及预测信号

利用中国南方66站降水观测资料和NCEP/NCAR再分析资料,采用经验正交函数分解(EOF)、合成分析和相关分析等方法,对夏季长江中下游和华南两类雨型进行了划分,对比分析了两类雨型同期大气环流和前期海温及环流的差异,以探讨两类雨型的形成机制及前期预测信号。结果表明:20世纪80年代之前华南型出现的频次较高,之后长江中下游型出现频次增多;长江中下游型年西太平洋副热带高压(副高)偏强偏西偏南,东亚夏季风(EASM)偏弱,副热带西风急流位置偏南,乌拉尔山阻塞高压(乌阻)和鄂霍次克海阻塞高压(鄂阻)较强,欧亚中高纬以经向环流为主,冷暖空气在长江中下游辐合,导致长江中下游降水偏多;华南型年大气环流与长江中下游型年大体相反,登陆华南的台风偏多,冷暖空气在华南地区辐合,导致华南地区降水偏多;其中副高的脊线位置和中高纬阻塞强弱是长江中下游型和华南型形成的关键因素。两类雨型前期海温分析表明,长江中下游型年,前冬赤道中东太平洋和印度洋偏暖,为典型的东部型El Ni?o,副热带南印度洋偶极子(SIOD)呈负位相,春季El Ni?o衰减,SIOD负位相也减弱,但印度洋持续增暖;华南型年,前冬和春季的海洋演变与长江中下游型年大体相反;关键区域海温与长江中下游夏季降水(YRR)和华南夏季降水(SCR)的年际关系存在年代际变化,YRR和SCR与前冬Ni?o3.4指数、SIOD指数和春季热带印度洋全区一致海温模态(IOBW)指数的相关关系在80年代之后逐步减弱,这主要是由于这三个关键海温指数与EASM及副高脊线的相关关系在80年代之后逐步减弱;两类雨型前期大气环流差异分析表明,春季大气环流的差异性要比前冬显著,长江中下游型年,春季副高、南海副高、马斯克林高压(马高)、澳大利亚高压(澳高)均偏强,大西洋欧洲区极涡强度偏弱,北太平洋涛动(NPO)呈正位相;华南型年春季的关键环流系统异常不明显,仅大西洋欧洲区极涡强度偏强,NPO呈负位相。前期海温演变及春季大气环流关键系统的异常可以作为两类雨型年的一些预测信号。

长江-81型手扶拖拉机冬停春用的维护保养

我区属江淮分水岭,既有丘陵又有淮河平滩,适合小型机械耕作.全区有长江-81型(六安手扶厂生产)手扶耕作机近十万台,占我区手扶拖拉机保有量的80%,承担着百分之八十的耕作任务.该机具有重量轻,油耗低,操作灵活,价格便宜等优点,深得农民喜爱.寿县丰庄镇有该机8000多台,全镇无耕牛,平均每户均有1～2台这样的手扶耕作机,主要用于农田作业.据调查,由于农机操作手不能正确地维护保养,导致百分之七十以上机械带病作业,增加了作业成本.特别在冬季停用过程中,农户大部分都习惯把机械放在外面简易棚内任其风吹、雨淋、受冻,致使一部分机械受损,更为严重的出现了机体、油管等部位冻裂,有的部件锈蚀严重,无法使用.为正确地保管、使用耕作机械,提高机械的使用寿命,建议有机农户应注意以下几点:

长江750改出哈利味

玩大排量摩托是大多数中国骑士此生难圆的梦,然而发烧级摩友在一辆老长江750身上用双手使自己的梦想成真。

长江750改进后的使用感受

环境保护是当今世界各国人民共同关心的一个问题,它关系到人类社会的生存和发展。在这个大前提下我从自身做起。

谈长江750摩托车离合器磨擦片被油污问题

长江750型摩托车采用的是干式离合器,所以离合器摩擦片工作面必须清洁、干净,不允许沾上油与水。否则,一是会导致离合器打滑,造成车辆行驶动力性能和加速性能下降。

长江750发动机曲柄机构组合的改制

长江750D型发动机是在750型机的基础上改进而成的,其绝大部分零组件与长江750原型机通用,但也增加了部分新件。如果用长江750原型机改装成长江750D发动机的话,有些新件是可以用750原型机的零件改制的,如曲柄机构组合等。这样既可以节省改装成本,又可以加快改装速度。因为像曲柄机构组合这样的大件在市面上很难买到。

长江CJ750摩托车点火系统的改进

长江CJ750型摩托车的点火系统为传统的触点式点火,由于初级电流是断电器触点接通和切断的,突出的问题是触点打开的瞬间,触点间易产生火花,将触点烧蚀,使接触电阻增大,造成初级电流减小,次级电压下降,火花能量减小.尤其是在发动机低速运转时,触点的烧蚀更加严重.

Ethogram of Yangtze finless porpoise calves (Neophocaena phocaenoides asiaeorientalis)

Underwater behavioral patterns of one Yangtze finless porpoise （Neophocaena phocaenoides asiaeorientalis） calf in captivity and those performed on the water surface by two calves in semi-natural environment were focally followed and continuously recorded until one year postpartum to construct the ethogram. The results indicate that 1） the three calves could display diverse and active behavioral patterns; 2） soon after birth, patterns critical for survival appeared first; 3） playful and social patterns predominated the ethogram; 4） most of the patterns were alike across age classes; 5） most of the patterns appeared at the calves’ early life stage. It is possible that the above characteristics are adaptively shaped by the aquatic and social life of this subspecies.

Variations in tidal currents and suspended sediment concentration of the upper part of the North Channel of Changjiang Estuary over the past 10 years

The tidal current duration （TCD） and velocity （TCV） and suspended sediment concentration （SSC） were measured in the dry season in December, 2011 and in the flood season in June, 2012 at the upper part of the North Channel of Changjiang Estuary. They were assimilated with the measured data in 2003, 2004, 2006 and 2007, using the tidal range＇s proportion conversion. Variations in TCD and TCV, preferential flow and SSC have been calculated. Influences of typical engineering projects such as Qingcaosha fresh water reservoir, Yangtze River Bridge, and land reclamation on the ebb and flood TCD, TCV and SSC in the North Channel for the last 10 years are discussed. The results show that： （1） currently, in the upper part of North Channel, the ebb tide dominates; after the construction of the typical projects, ebb TCD and TCV tends to be larger and the vertical average ebb and flood SSC decrease during the flood season while SSC increases during the dry season; （2） changes in the vertical average TCV are mainly contributed by seasonal runoff variation during the flood season, which is larger in the flood season than that in the dry season; the controlling parameters of increasing ebb TCD and TCV are those large-scale engineering projects in the North Channel; variation in SSC may result mainly from the reduction of basin annual sediment loads, large-scale nearshore projects and so on.

Evolution of Main Characteristics of the Registered Cotton Cultivars in National Cotton Regional Trials in Yangtze River Valley

[Objective] The aim of this study was to characterize the national regis- tered varieties selected from cotton regional trials in Yangtze River Valley （YaRV） in recent years. [Method] Cotton cultivar classification and comprehensive evaluation index were set up based on national cotton registration standard. GGE biplot method was adopted to analyze the correlation of major breeding target characters of 53 national registered cotton varieties in cotton regional trials in YaRV during 1981-2012. According to the shift of check cultivars in cotton regional trials in the past, the cotton regional trial practice since 1981 was divided into five periods. The dynamic of cultivar type＇s proportion and the evaluation index scores was analyzed across the five periods. [Result] There existed intricate interrelationship among cotton breeding target traits, which constrained it necessary to construct indices for com- prehensive evaluation of cotton varieties. The dynamic of cultivar types in the five periods indicated that type II varieties emerged since Simian 3 period and then its proportion decreased gradually; type Ⅲ varieties maintained a certain proportion in each period and kept on the rise overall; type Ⅳvarieties occupied the majority pro- portion of registered cultivars before 1993, but a minor proportion since Simian 3 period. On the other side, the change trend of the evaluation index demonstrated that the varieties registered before 2003 did not pass the qualified line at present. The peak scores appeared in the varieties registered during 2004-2008. The scores of the varieties registered after 2009 were only slightly over the qualified line. [Conclusion] More attention should be paid to the improvement and evaluation of micronaire, so as to guide the simultaneous development of high yielding and fiber quality in cotton breeding and registration procedure in YaRV.

长江下游某水源型水库抗生素抗性基因污染研究

抗生素抗性基因是水环境中的新型污染物.为了探究夏季时期长江下游某水源型水库抗生素抗性基因(Antibiotic Resistance Genes,ARGs)污染赋存特征,分别采集了水体和沉积物样本并使用高通量荧光定量PCR和实时荧光定量PCR进行研究.结果表明,长江下游水体中检测出104种ARGs,水库水体中检测出118种ARGs,沉积物中检测出124种ARGs.β-内酰胺类、多重抗药类、其他类共54种ARGs为水库中占主导的抗性基因.抗性基因绝对丰度在水体中呈现从长江下游到库内富集的趋势,这表明水环境中的ARGs在水库中富集;相对丰度特征呈现长江下游水介质与库内水介质聚类,水介质与沉积物介质聚类.水体样本的整合子(CintⅠ-1(class 1)、intⅠ-1(clinical))与其ARGs总量之间存在显著的相关性(r=0.750,p<0.05;r=0.971,p<0.05),说明整合子对ARGs转移和富集具有重要作用.

Spatial distribution and abundance of small fishes in Xiaosihai Lake,a shallow lake along the Changjiang (Yangtze) River, China

Spatial distribution and abundance of small fishes were studied in autumn 2007 in the Xiaosihai Lake, a shallow lake along the middle reach of the Changjiang （Yangtze） River. Based on the plant cover, the lake was divided into three major habitats： Myriophyllum spicaturn habitat （MS habitat）, Trapa bispinosa habitat （TB habitat）, and non-vegetation habitat （NV habitat）. A modified pop-net was used for quantitative sampling of small fishes in the three habitats, and the Zippin＇s removal method was used for estimating densities of the small fishes. A total of 13 species belonging to 5 families were collected, with 11 species in MS habitat, 7 species in TB habitat, and 5 species in NV habitat. Habitat type had significant effect on the spatial distribution of small fishes. The Shannon-Wiener diversity index in the MS, TB and NV habitats were 1.28, 0.56 and 0.54, respectively. The total density and biomass of small fishes were significantly higher in the MS habitat （13.68 ind/m^2 and 4.44 g/m^2） than in the TB habitat （1.41 ind/m^2 and 0.54 g/m^2） and the NV habitat （1.08 ind/m^2 and 0.40 g/m^2）, and were not significantly different between the TB habitat and the NV habitat. Water depth had no significant effect on spatial distribution of the small fishes. It was suggested that vegetation type played an important role in habitat selectivity of small fishes, and the presence of submersed vegetation should be of significance in the conservation of small fish diversity.

Simulated circulations off the Changjiang (Yangtze) River mouth in spring and autumn

The circulations off the Changjiang mouth in May and November were simulated by a three dimension numerical model with monthly averaged parameters of dynamic factors in this paper. The area covers the East China Sea (ECS), Yellow Sea and Bohai Sea. Simulated results show that the circulation off the Changjiang mouth in spring and autumn is mainly the Changjiang runoff and Taiwan Warm Current (TWC). The Changjiang discharge is much larger in May than in November, and the wind is westward in May, and southward in November off the Changjiang mouth. The runoff in May branches in three parts, one eastward flows, the other two flow northward and southward along the Subei and Zhejiang coast respectively. The Changjiang diluted water expands eastward off the mouth, and forms a strong salinity front near the mouth. Surface circulation in autumn is similar to that in winter, the runoff southward flows along the coast, and the northward flowing TWC becomes weaker compared to that in spring and summer. The bottom circulations in May and November are mainly the runoffnear the mouth and the TWC offthe mouth, and the runoff and TWC are greater in May than in November.

Nutrient fluxes in the Changjiang River estuary and adjacent waters——a modified box model approach

To solve nutrient flux and budget among waters with distinct salinity difference for water-salt- nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang （Yangtze） River estuary （CRE） and adjacent waters （30.75°-31.75°N, 122°10′-123°20′E）. Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model （ROMS）. Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction （upwelling flux and upward diffusion flux regions overlap largely all the year）. Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP （dissolved inorganic phosphate） occurs in summer. Additional to the fluxes of the ChanNiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional one in estimating nutrient fluxes in a complicated hydrodynamic current system and provides a modified box model approach to material flux research.

Development and Validation of National Cotton Cultivar Registration Index Model in Yangtze River Valley

[Objective] Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calculation process in national cotton registration procedure, and thus to enhance the practical application of cultivar regis- tration index in cotton breeding ancl cotton recommending. [Method] By means of correlation analysis, partial correlation analysis and path analysis methods, the cor- relation of cotton main properties and their effects on cultivar registration index were explored using the dataset of national cotton regional trials in Yangtze River Valley during 1996-2013. The cultivar registration index model was constructed with step- wise regression statistical technique to ascertain the quantitative relationship of main characters with cultivar registration index, and the regional cotton trial dataset in 2013 was used to validate the model. [Result] Several characters with larger deter- minants to cultivar registration index were screened out,ie. lint yield increase ratio, pro-frost yield ratio, verticillium wilt index, fiber strength, fusarium wilt index and mi- cronaire value. The cultivar registration index model defined the functional relation- ship of cultivar registration index with the selected main characters, among which lint yield increase ratio, fiber strength and micronaire value contributed most to culti- var registration index. The model validation with regional cotton trials in 2013 indi- cated the root mean square error, RMSE was only 2.77, and the variation coeffi- cient was 6.77%, which confirmed the model prediction effect was quite perfect. [Conclusion] The developed cultivar registration index model was reliable enough to simulate the complicated scoring system in cultivar registration procedure, also sim- plified cotton registration process, and enhanced the practicability of the cultivar reg- istration index.

Direct Climatic Effect of Aerosols and Interdecadal Variations over East Asia Investigated by a Regional Coupled Climate-Chemistry/Aerosol Model

The direct climatic effect of aerosols for the 1980-2000 period over East Asia was numerically investigated by a regional scale coupled climate-chemistry/ aerosol model, which includes major anthropogenic aerosols （sulfate, black carbon, and organic carbon） and natural aerosols （soil dust and sea salt）. Anthropogenic emissions used in model simulation are from a global emission inventory prepared for the Intergovernmental Panel on Climate Change Fifth Assessment Report （IPCC AR5）, whereas natural aerosols are calculated online in the model. The simulated 20-year average direct solar radiative effect due to aerosols at the surface was estimated to be in a range of-9- -33 W m-2 over most areas of China, with maxima over the Gobi desert of West China, and-12 W m-2 to -24 W m-2 over the Sichuan Basin, the middle and lower reaches of the Yellow River and the Yangtze River. Aerosols caused surface cooling in most areas of East Asia, with maxima of-0.8℃ to -1.6℃ over the deserts of West China, the Sichuan Basin, portions of central China, and the middle reaches of the Yangtze River. Aerosols induced a precipitation decrease over almost the entire East China, with maxima of-90 mm/year to -150 mm/year over the Sichuan Basin, the middle reaches of the Yangtze River and the lower reaches of the Yellow River. Interdecadal variation of the climate response to the aerosol direct radiative effect is evident, indicating larger decrease in surface air temperature and stronger per- turbation to precipitation in the 1990s than that in the 1980s, which could be due to the interdecadal variation of anthropogenic emissions.