Preface to Special Issue on the National Report to the IUGG Centennial by CNC-IAMAS(2011–2018)

正The 27th General Assembly of the International Union of Geodesy and Geophysics(IUGG), which also marks the 100 th anniversary of IUGG, will be held during 8–18 July 2019 in Montréal, Canada. The Chinese National Committee(CNC)for the International Association of Meteorology and Atmospheric Sciences(IAMAS) has a more than 30-year tradition of     

Properties and organic activation of ocean clay in the East Pacific

In order to make use of ocean clay reasonably and excavate its potential applications the properties of ocean clay in Chinese investigating area of the East Pacific have been tested with the chemical analysis, XRFS, ICP/MAS, granulometry and SSA, etc. The results show that the clay sediments of this area are rich in clay minerals, fine granularity, bigger SSA, bigger water absorbability and lower ion changing ability etc. To improve the adaptability of ocean clay and macromolecule materials, using the dry milling method with silane, aluminate, stearic acid coupling agents etc the properties of ocean clay are improved. The effect has been evaluated by testing the water absorbing of the modified ocean clay and their dispersing in paraffin liquid. The result is that KH550 is better than any other active reagents, and the best activation technics is that 1.5% (volume) of KH550 quantity, 20min of milling time. The DTA, XRD, SEM and IR analyses and SSA testing show that the organic activation can not change the mineral structure but can densify the structure of clay, and activation mechanism is chemical covered mainly and chemical combined secondly.     

Lead contamination of small cetaceans in European waters--the use of stable isotopes for identifying the sources of lead exposure

Lead concentrations and isotopic composition have been measured in bone and teeth of small cetaceans belonging to three species (Delphinus delphis, Phocoena phocoena and Stenella coeruleoalba), to evaluate the toxicological risk and to determine sources of lead in the European waters. Lead concentrations, far lower than threshold value inducing toxic effects in human, were higher in teeth than in bones, but highly correlated between the two tissues (r=0.92, p<0.001). Large variations of 206Pb/207Pb values in bone tissue showed that cetaceans must be submitted to various atmospheric influences. No geographical differences appeared which is consistent with studies on their distribution indicating seasonal movements between Brittany waters and the Bay of Biscay. The negative correlation between 206Pb/207Pb ratios and age of the individuals reflected the decrease in the production of alkyl lead in Europe, i.e., the increasing use of unleaded gasoline.     

Does sediment grain size affect diatom grazing by harpacticoid copepods?

Estuarine soft sediments support a diverse group of eukaryotic and prokaryotic organisms though the role of the sediment per se for the functioning of these organisms remains largely unknown. The present study aimed to test the effect of sediment grain size on the grazing activities of harpacticoid copepods. In controlled experiments, two common intertidal harpacticoid species (Paramphiascella fulvofasciata and Nitokra spinipes) were each offered a mix of two benthic diatom species (Navicula phyllepta and Seminavis robusta) in different sedimentary conditions. Several microcosms were created using a variety of sediment types, including fine silt (<63 microm), coarser grained sands (125-250, 250-450, 100-300 microm), artificial 'sediments' of glass beads (250-500, 2000 microm) and even the absence of sediment was tested. The diatoms were enriched in the stable carbon (13)C to facilitate tracing in the harpacticoids. Both copepod species were able to graze on the diatoms with highest uptake when sediment was absent. In contrast, both harpacticoid species showed no uptake in silty conditions. In general, grazing was favoured when mean sediment grain size increased. The strong negative effect of fine grains on the grazer's efficiency can be explained by the resulting differences in the structure (and accessibility) of the diatom biofilm on the one hand and the mobility of the grazer on the other hand. In view of the subtle equilibrium between primary producers and grazers, these results might have important implications for the effect of siltation of tidal flats due to, e.g., human activities.     

Predicting impacts of climate change on the biogeographic patterns of representative species richness in Prydz Bay-Amery Ice Shelf

The research on the biological ecology of the Prydz Bay-Amery Ice Shelf in East Antarctica is inadequate under the increasing threat from climate change, especially for Antarctic fish and krill. The Dynamic Bioclimatic Envelope Model(DBEM) has been widely used in predicting the variation of species distribution and abundance in ocean and land under climate change; it can quantify the spatiotemporal changes of multi population under different climate emission scenarios by identifying the environm...     

A New Emission Mode of PSR B1859+07

Previous studies have identified two emission modes in PSR B1859+07: a normal mode that has three prominent components in the average profile, with the trailing one being the brightest, and an anomalous mode(i.e., the A mode) where emissions seem to be shifted to an earlier phase. Within the normal mode, further analysis has revealed the presence of two submodes, i.e., the cW mode and c B mode, where the central component can appear either weak or bright. As for the anomalous mode, a new bright ...     

Photometric Properties and Stellar Parameters of the Rapidly Rotating Magnetic Early-B Star HD 345439

We first present the multicolor photometry results of the rapidly rotating magnetic star HD 345439 using the Nanshan One-meter Wide-field Telescope.From the photometric observations,we derive a rotational period of 0.7699±0.0014 day.The light curves of HD 345439 are dominated by the double asymmetric S-wave feature that arises from the magnetic clouds.Pulsating behaviors are not observed in Sector 41 of the Transiting Exoplanet Survey Satellite.No evidence is found of the occurrence of centrifug...     

Challenges in the Detection and Attribution of Northern Hemisphere Surface Temperature Trends Since 1850

Since 2007, the Intergovernmental Panel on Climate Change(IPCC) has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST) estimates for concluding that post-1950s global warming is mostly human-caused. In Connolly et al., we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI) and ST data sets.We compiled 16 TSI and five ST data sets and found by alter...     

First Detailed Analysis of a Relatively Deep,Low Mass-ratio Contact Binary:ATO J108.6991+27.8306

We present the first detailed photometric analysis of ATO J108.6991+27.8306(hereinafter as J108). The shortperiod close binary J108 was observed by the Nanshan 1 m Wide Field Telescope of the Xinjiang Astronomical Observatory. The obtained BVRI-band light curves were used to determine the photometric solution by using the 2003 version of the Wilson-Devinney code. J108 is a typical deep( f > 50%), low mass ratio(q < 0.25)overcontact binary system with a mass ratio of q = 0.1501 and a fill-o...     

Spatio-temporal variations of harmful algal blooms along the coast of Guangdong,Southern China during 1980–2016

Harmful algal blooms(HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system(GIS) was utilized to determine spatial and temporal characteristics of HAB events in the coastal waters of Guangdong from 1980–2016. We analyzed distribution patterns and characteristics of HABs by dividing the coast of Guangdong into well-known bays, estuary and coastal waters. Results showed that there were a total of 337 HABs recorded in Guangdong coastal waters. Spatial and temporal distributions varied among dif ferent regions. Most HABs occurred in the Mirs Bay, followed by the west coast of Daya Bay, while a few occurred in the west and east coasts of Guangdong but with an increasing trend in the past two decades. HABs occurred mostly in warmer months of March to May in the western coast of Guangdong, March and April in Mirs Bay, April in Zhujiang(Pearl) River estuary, November in eastern coast of Guangdong. For Daya Bay, most HABs were reported between March and September.The most frequently occurring HABs species were Noctiluca scintillans, P haeocystis globosa, Skeletonema costatum and Scrippsiella trochoidea, occurring mostly in Mirs Bay, western Guangdong coast area, eastern Guangdong coast area and Zhujiang River estuary and Daya Bay, respectively. Ichthyotoxic blooms were more common than toxic blooms, and Heterosigma akashiwo, Chattonella marina, Karenia mikimotoi and P haeocystis globosa were the most common ichthyotoxic species. Our results provide baseline information useful for policy making and management of HABs in the region.