Daily precipitation distributions over the intra-Americas sea and their interannual variability

The seasonal (March to October) and interannual variability of the cumulative distribution function (CDF) of precipitation is examined for Meso-America, the eastern Pacific and western Atlantic, commonly referred to as the intra-Americas sea (IAS). Large-area precipitation CDFs were constructed over land and temperature pools greater than 28.5° C and between 26.5° and 28.5° C. The cooler waters tend to have their precipitation distributions shifted to lower values as compared to land and the western hemisphere warm pool (WHWP). The land and the WHWP have similar precipitation distributions from March to May. From June to October the land histogram of precipitation is narrower (less light and heavy rainfall) relative to the WHWP histogram. The highest probability of finding heavy to extreme precipitation over the WHWP is in June. From 1997 to 2008, in the summer months, the El Niño/Southern Oscillation (ENSO) is related to the CDFs of precipitation over land, where during El Niño there is a shift toward lower daily rain totals. There is not a strong relationship between ENSO and the CDFs of precipitation over the ocean pools. Finally, a large WHWP in May-June-July is related to the CDF of precipitation over the WHWP in October, namely a shift towards higher daily rain totals and more extreme events. The size of the July WHWP explains 75% of the variability in the frequency of rainfall greater than 50 mm within the WHWP in October, and the root mean square error between the observed points and the linear models is about 0.005. However, the reason for this apparent predictability is not simply due to a warm seasonal anomaly leading to local thermodynamic effects. The concurrent correlation between the size of the WHWP in October and the CDF of precipitation therein is small, indicating a lack of a contemporaneous response. Here it is shown through atmospheric-oceanic reanalysis that rainfall extremes in October are dependent upon the development of the Atlantic portion of the WHWP in May-June-July. Large WHWPs in these months are consistent with an early onset of the Atlantic warm pool and atmospheric instability over Central America leading to extreme precipitation events in the fall.     

High resolution oxygen isotope and grayscale records of a medieval fossil giant clam (Tridacna gigas) in the South China Sea：physiological and paleoclimatic implications

Mollusks are well known for their detailed recording of paleoenvironmental and paleoclimatic changes in their carbonate shells. In this study, we constructed 18-year blue color intensity and oxygen isotope profiles of a 14 C dated(AD 990±40) fossil giant clam, Tridacna gigas, from Shidao Island, South China Sea. The δ18O profile of the T. gigas specimen displayed regular annual cycles and was probably controlled by seasonal variations of the climatic parameters. The blue color intensity profile showed good agreement with the δ18O series, and both had 18 clear annual cycles in accordance with the 18 visually identified annual growth bands. The annual shell growth rate determined from the blue color intensity and oxygen isotope profiles indicated that the annual shell increment of the Tridacna specimen was stable after the onset of sexual maturity. Spectral analysis of the δ18O and blue color intensity time series suggested that the El Nio–Southern Oscillation(ENSO) period observed in the instrumental temperature and precipitation records of the South China Sea during the past 50 years also existed in medieval times. Our results showed that fossil giant clams could provide a good archive of historical intra-seasonal to decadal climate variations.     

基于个体模型的东海鲐鱼渔场形成机制研究

鲐鱼Scomber japonicus资源丰富,在我国近海渔业中占有重要地位。其渔场的形成受海洋环境的制约,本文确定鲐鱼运动和物理环境之间的响应关系,建立起了基于个体的东海鲐鱼生长洄游模型。结果显示,鲐鱼集群分布与捕捞生产渔场基本吻合,鲐鱼聚集主要受台湾暖流、大陆沿岸水、黑潮影响,往往集群在一定温度范围内并在冷暖交汇区温盐梯度大偏暖水一侧。在台湾暖流和沿岸水交汇的锋面附近、台湾暖流暖水舌前端、黑潮与中国大陆沿岸水形成的潮境区域均有大量的鲐鱼聚集,并形成渔场。产卵位置的变动使偏西产卵位置的鲐鱼由于受台湾暖流影响较大,鲐鱼会呈长带状大量聚集在台湾暖流和沿岸水的锋面附近,并使在台湾暖流暖水舌前端的聚集数量增多,而偏东的产卵的鲐鱼受黑潮影响较大,聚集分布范围较大,会使黑潮形成的锋面附近聚集数量增多,而使台湾暖水舌的前端的聚集量减少。正常产卵位置在生存率方面是最佳产卵位置。研究表明鲐鱼所处空间位置不同,会影响其集群的位置,用数值模型验证了物理环境会对鲐鱼的洄游和渔场的形成产生影响。     

夏季台湾海峡水及黑潮次表层涌升水向东海近陆架区营养盐输送通量的估算

According to historical mean ocean current data through the field observations of the Taiwan Ocean Research Institute during 1991–2005 and survey data of nutrients on the continental shelf of the East China Sea(ECS) in the summer of 2006, nutrient fluxes from the Taiwan Strait and Kuroshio subsurface waters are estimated using a grid interpolation method, which both are the sources of the Taiwan Warm Current. The nutrient fluxes of the two water masses are also compared. The results show that phosphate(PO4-P), silicate(SiO3-Si) and nitrate(NO3-N) fluxes to the ECS continental shelf from the Kuroshio upwelling water are slightly higher than those from the Taiwan Strait water in the summer of 2006. In contrast, owing to its lower velocity, the nutrient flux density(i.e., nutrient fluxes divided by the area of the specific section) of the Kuroshio subsurface water is lower than that of the Taiwan Strait water. In addition, the Taiwan Warm Current deep water, which is mainly constituted by the Kuroshio subsurface water, might directly reach the areas of high-frequency harmful alga blooms in the ECS.     

在闽东海域发现的石珊瑚的种类组成和分布

首次报道了闽东海域分布的3种石珊瑚,分别为造礁石珊瑚陀螺珊瑚（Turbinaria sp．）、非造礁石珊瑚猩红筒星珊瑚（Tubastrea coccinea Lesson）和1个珊瑚待定种,其中陀螺珊瑚和1个珊瑚待定种为中国新记录．珊瑚分布面积约3．24km2,主要呈零星斑块状分布在岛礁周围水深2—25m近岸岩礁区．2012年5～8月对闽东台山列岛和星仔列岛4km2范围内的55个岛礁近岸海域进行4个航次的调查表明,珊瑚的分布总体上南部的台山列岛海域分布数量多于北部的星仔列岛,海岛东部海域略多于西部．研究认为,闽东海域发现陀螺珊瑚说明其分布主要受台湾暖流的影响,揭示我国大陆沿岸造礁石珊瑚分布北缘可能扩展到台山列岛和星仔列岛．     

印-太暖池区全新世Mg/Ca温度转换中的盐度因素

有孔虫Mg/Ca温度计是古海洋学研究中恢复古温度的重要手段之一。然而,越来越多的研究表明,Mg/Ca温度计的准确性受多种因素的影响,特别是盐度的控制十分重要。文章实测并搜集整理了印-太暖池地区全新世(大约11kaB.P.以来)1000余个浮游有孔虫Mg/Ca比值数据,分别利用包含和不包含盐度信息的两个常用转换方程求取了古海水温度,并将二者进行了对比,旨在探讨盐度因素对Mg/Ca温度计的影响。结果显示,在表层水温大约28℃以下,两个方程获得的结果几乎一致,平均差异为0.07℃;在表层水温28℃以上,二者平均相差大约1℃。此外,表层海水盐度越低,包含盐度信息的转换方程获得的古海水氧同位素的值越大。上述结果揭示盐度对该地区有孔虫Mg/Ca比值的影响效应不明显。     

Sensitivities of tornadogenesis to drop size distribution in a simulated subtropical supercell over eastern China

ABSTRACT Numerical simulations with the Advanced Regional Prediction System （ARPS） model were performed to investigate the impact of microphysical drop size distribution （DSD） on tornadogenesis in a subtropical supercell thunderstorm over Anhui Province, eastern China. Sensitivity experiments with different intercept parameters of rain, hail and snow DSDs in a Lin-type microphysics scheme were conducted. Results showed that rain and hail DSDs have a significant impact on the simulated storm both microphysically and dynamically. DSDs characterized by larger （smaller） intercepts have a smaller （larger） particle size and a lower （higher） mass-weighted mean fall velocity, and produce relatively stronger （weaker） and wider （narrower） cold pools through enhanced （reduced） rain evaporation and hail melting processes, which are then less favorable （favorable） for tornadogenesis. However, tornadogenesis will also be suppressed by the weakened mid-level mesocyclone when the cold pool is too weak. When compared to a U.S. Great Plain case, the two microphysical processes are more sensitive to DSD variations in the present case with a higher melting level and deeper warm layer. This suggests that DSD-related cloud microphysics has a stronger influence on tornadogenesis in supercells over the subtropics than the U.S. Great Plains.     

Nutrient structure of the Taiwan Warm Current and estimation of vertical nutrient fluxes in upwelling areas in the East China Sea in summer

Based on field data for nutrients collected on the continental shelf of the East China Sea (ECS) during summer 2006, the structure and variations of nutrients in every water mass related to the Taiwan Warm Current (TWC) were analyzed. The supplementary effect of nutrient of upwelling on harmful algal blooms (HABs) in the ECS was also estimated, based on upwelling data. Then the maintenance contribution of nutrient of upwelling to HABs was assessed. The results showed that N/P ratio is fairly low in both surface and deep layers of the TWC, which possibly controls nutrient structure of the HABs-frequently-occuring areas. In upwelling areas, the rate of phosphate (PO₄-P) uptake exceeds that of nitrate (NO₃-N) of the TWC. The TWC may relieve PO₄-P limitation during the process of HABs. Furthermore, upwelling plays an important role in providing nutrients to HABs. After estimating nutrient fluxes (NO₃-N, PO₄-P, SiO₃-Si) in the upwelling areas along a typical section (S07), the results showed that the nutrient uptake rate is the greatest at 10–20 m below euphotic zone, sustaining the ongoing presence of HABs. The uptake rate of PO₄-P is the highest among dissolved inorganic nutrients. Therefore, upwelling is most likely the main source of PO₄-P supply to HABs.     

云GIS应用于数字城市设计与实现

针对数字城市地理空间框架建设中存在的问题,本文研究和设计实现云环境下GIS应用,构建云GIS实验环境,和传统GIS环境实验结果对比,得出结论：云GIS在基础设施框架、提高硬件资源利用率以及提供高性能的服务方面具有诸多优势,能解决现在数字城市项目建设中存在的问题,值得研究和应用推广。     

Spatial Differentiation of the Coupling Characteristics of Soil Carbon and Nitrogen on Mulberry Plantations in China

Soil is the most important carbon pool of the mulberry plantation ecosystem, so understanding the characteristics of the soil carbon pool in mulberry plantations provides an important basis for the research of carbon sinks in economic forest ecosystems and farmland ecosystems. In order to explore the spatial differentiation pattern of the relationship between carbon and nitrogen in mulberry plantation soil, this study analyzed the organic carbon content and total nitrogen content of the surface soil layer (0-20 cm) and the subsurface soil layer (20-40 cm) of 475 mulberry plantations in five major regions of China, Southwest China (SWC), Central South China (CSC), East China (EC), North China (NC), and Northwest China (NWC). The research showed seven key aspects of this system. (1) The soil organic carbon of mulberry plantations was significantly different at the two soil depths. The average content of organic carbon in the surface layer of mulberry plantation soil was 10.71±7.01g kg^?1, which was 37.13% higher than that of the subsurface layer. (2) The soil organic carbon of mulberry plantations had significant differences in spatial differentiation, which was manifested as SWC>CSC>EC>NC>NWC. (3) The total nitrogen content in mulberry plantation soil had significant responses to the region, the soil layer depth, and the interaction between the region and soil layer depth. Among the regions, NWC had no significant difference between the surface layer and subsurface layer of the soil. EC had the maximum difference in total nitrogen content, with the total nitrogen content in the surface soil layer being 56.68% higher than that of the subsurface soil layer. The total nitrogen contents of the surface soil layers in the SWC and NC were 34.27% and 20.79% higher than those of the respective subsurface soil layers. (4) The mulberry plantation soil C/N ratios had a significant response to regional differences, as NWC>SWC> EC>CSC>NC, but this ratio had no significant response to soil depth. (5) Soil pH had significant spatial differentiation in relation to soil organic carbon and total nitrogen content in mulberry plantations. NWC had no significant correlation between pH and organic carbon or total nitrogen content, while CSC had a significant positive correlation between pH and both soil organic carbon and total nitrogen content. Other regions showed significant negative correlations between pH and both organic carbon and total nitrogen content. (6) There was a significant negative correlation between the C/N ratio of the surface soil layer and pH in mulberry plantations, which was mainly contributed by SWC, while the other regions’ surface soil layers had no significant correlations between C/N ratio and pH. (7) There was no significant correlation between the C/N ratio and pH in the subsurface soil layer in mulberry plantations. These results reveal that in either the research on mulberry plantation carbon pools or the innovation of green and low-carbon planting technology in mulberry plantations, the spatial differentiation characteristics of soil must be considered. Furthermore, the spatial differentiation of soil organic carbon can be used as the basic foundation for the planning and design of mulberry afforestation or ecological restoration projects.