Dinoflagellates in a mesotrophic,tropical environment influenced by monsoon

The changes in dinoflagellate community structure in both – the water column and sediment in a mesotrophic, tropical port environment were investigated in this study. Since the South West Monsoon (SWM) is the main source of climatic variation, observations were made during two consecutive post-monsoon periods (2001 and 2002) and the intervening pre-monsoon period (2002). The pre-monsoon period supported a more diverse dinoflagellate community in the water column compared to both post-monsoon periods. Heterotrophic dinoflagellates were abundant in the water column as well as sediment. A seasonal cycling between vegetative and resting cysts of autotrophic and heterotrophic dinoflagellates governed by the environmental characteristics of the study area was observed. Temperature, salinity and suspended particulate matter were the main factors affecting dinoflagellate community structure in both the water column and sediment. The dominant dinoflagellates in the water column differed during both post-monsoon periods that followed two dissimilar monsoon events. Prorocentroids and gonyaulacoids dominated the water column subsequent to the 2001 SWM, whereas dinophysoids and unidentified tiny dinoflagellates dominated during the next post-monsoon period. The 2001 SWM started in May, peaked during June–July and reduced gradually to end in October. The 2002 SWM was erratic; it started late (in June) and ended earlier (in September). These observations highlight the potential of the SWM to influence the community structure of dinoflagellates in tropical waters and points to the importance of long-term studies to discern robust variations in dinoflagellate communities in response to fluctuating monsoon regimes.     

Spatial and temporal variation of Palaemon adspersus, Palaemon elegans, and Crangon crangon (Decapoda: Caridea) in the southern Black Sea

In order to characterize the seasonal, bathymetric, and spatial distribution of the species, Palaemon adspersus, Palaemon elegans, and Crangon crangon, shrimps were sampled with a beam trawl in four stations at depths between 1 and 30 m from February 2002 to January 2004 on the Sinop Peninsula coasts of the southern Black Sea. One-way analysis of similarity (ANOSIM) results demonstrated that the caridean composition was significantly different (p < 0.001) between seasons and between sampling areas. No significant relationship of the caridean composition was evident between depth zones ranging from 1 to 30 m. These three carideans occurred together in 28.5% of the sampling occasions. Different seasonal migration pattern was evident for all the three species. Palaemon adspersus migrated inshore during relatively higher water temperatures, whereas C. crangon density decreased in the shallow waters during the same period, and P. elegans population was mostly observed at depth zones of 5–10 m and was only observed in the 30 m depth zone in winter. The abiotic factors that characterize the coexistence of these three carideans were primarily determined by the habitat types and bottom structures.     

Comparison of some vegetation indices in seasonal information

With the development of vegetation indices, the reflection capability of vegetation indices to the state of vegetation has been improved in various degrees. Especially, the vegetation index of Terra/MODIS-EVI is believed to have the highest sensitivity to the seasonality of vegetation. This study compares the reflection susceptibility of three vegetation indices （NOAA/AVHRR-NDVI, Terra/MODIS-NDVI and Terra/MODIS-EVI） to the seasonal variations of vegetation in the mid-south of Yunnan Province of China. It has been found that Terra/MODIS-EVI does best in the elimination of external disturbance. Firstly, it obviously improves the linear relationship with vegetation cover degree, especially in the high vegetation coverage area. Secondly, it avoids the emergence of vegetation index saturation. Thirdly, it reduces the environmental influence including both effects of atmosphere and soil. So it is believed that the Terra/MODIS-EVI can offer excellent tool for quantitative research of remote sensing, and has realized to be oriented by data with high quality.     

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Annual time-series analyses of total gaseous mercury measurement and its impact factors on the Gongga Mountains in the southeastern fringe of the Qinghai-Tibetan Plateau

Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station （102°72′E 29°92′N,1640 m asl） of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences （CAS） from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers （Tekran 2537A）. Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury （TGM） covering the measurement periods was 4±1.38 ng·m^-3 （N=57310）,which is higher than the global background level of approximately 1.5～2.0 ng·m^-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m^-3 and lowest in summer with 3.17 ± 0.67 ng·m^-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation （UV） and atmospheric pressure at the whole measurement stage,and t     

海南岛和厦门红树林湿地CH4 排放的时空变化

研究了海南岛和厦门的河口海岸红树林湿地、海岸光滩及红树林伐迹地CH4排放的时空变化。海南岛长宁站位海莲林连续两年的CH4排放率均表现为外滩>中滩>内滩的空间变化模式,与土壤含水量的空间变化一致,而与土壤盐度的空间变化相反;但1997年在其余五个红树林湿地的CH4排放率表现出不同的空间变化规律,且大多与土壤理化因子不呈对应关系。各红树林湿地的最低CH4排放率均出现在冬季。红树林湿地年CH4排放率高于海岸光滩而低于红树林伐迹地。     

Improving multi-model ensemble probabilistic prediction of Yangtze River valley summer rainfall

Seasonal prediction of summer rainfall over the Yangtze River valley(YRV) is valuable for agricultural and industrial production and freshwater resource management in China, but remains a major challenge. Earlier multi-model ensemble(MME) prediction schemes for summer rainfall over China focus on single-value prediction, which cannot provide the necessary uncertainty information, while commonly-used ensemble schemes for probability density function(PDF) prediction are not adapted to YRV summer rainfall prediction. In the present study, an MME PDF prediction scheme is proposed based on the ENSEMBLES hindcasts. It is similar to the earlier Bayesian ensemble prediction scheme, but with optimization of ensemble members and a revision of the variance modeling of the likelihood function. The optimized ensemble members are regressed YRV summer rainfall with factors selected from model outputs of synchronous 500-h Pa geopotential height as predictors. The revised variance modeling of the likelihood function is a simple linear regression with ensemble spread as the predictor. The cross-validation skill of 1960–2002 YRV summer rainfall prediction shows that the new scheme produces a skillful PDF prediction, and is much better-calibrated, sharper, and more accurate than the earlier Bayesian ensemble and raw ensemble.     

Comparison of Daily Extreme Temperatures over Eastern China and South Korea between 1996–2005

This paper examined the decadal mean, seasonal cycle, and interannual variations of mean and extreme temperatures using daily temperature and relative humidity data from 589 stations over eastern China and South Korea between 1996–2005. The results show that the decadal mean Tm (mean daily mean temperature) and the TNn (minimum daily minimum temperature) increase from north to south; the opposite spatial gradient is found in the DTR (diurnal temperature range); the value of the DTR over South Korea is in- b...     

珠江三角洲区域大气输送和扩散的季节特征

根据1985—2004年NCEP/NCAR再分析资料,采用HYSPLIT扩散模式和虚拟源方法,模拟分析了珠江三角洲大气污染物的空间和时间分布状况,初步讨论了珠江三角洲大气输送和扩散的季节特征,及其长期变化趋势。结果表明:珠江三角洲大气的输送和扩散有明显的季节变化特征,春、夏季大气污染物汇聚区位于珠江三角洲的西北侧,秋、冬季位于偏西侧;春、夏季的汇聚区明显强于秋、冬季。春、夏季大气分别向珠江三角洲西北和偏北方向的山区输送和扩散,而秋、冬季则沿着较为平坦的粤西海岸,向西南偏西方向输送和扩散。秋、冬季大气污染物的滞留时间明显比春、夏季短。1985—2004年大气输送和扩散能力存在年际差异,其中以2004年的输送和扩散能力最弱、1996年最强。     

Evaluating the Capabilities of Soil Enthalpy,Soil Moisture and Soil Temperature in Predicting Seasonal Precipitation

Soil enthalpy(H) contains the combined effects of both soil moisture(w) and soil temperature(T) in the land surface hydrothermal process. In this study, the sensitivities of H to w and T are investigated using the multi-linear regression method.Results indicate that T generally makes positive contributions to H, while w exhibits different(positive or negative) impacts due to soil ice effects. For example, w negatively contributes to H if soil contains more ice; however, after soil ice melts,w exerts positive contributions. In particular, due to lower w interannual variabilities in the deep soil layer(i.e., the fifth layer), H is more sensitive to T than to w. Moreover, to compare the potential capabilities of H, w and T in precipitation(P) prediction, the Huanghe–Huaihe Basin(HHB) and Southeast China(SEC), with similar sensitivities of H to w and T,are selected. Analyses show that, despite similar spatial distributions of H–P and T –P correlation coefficients, the former values are always higher than the latter ones. Furthermore, H provides the most effective signals for P prediction over HHB and SEC, i.e., a significant leading correlation between May H and early summer(June) P. In summary, H, which integrates the effects of T and w as an independent variable, has greater capabilities in monitoring land surface heating and improving seasonal P prediction relative to individual land surface factors(e.g., T and w).