Characteristics and indications of hydrogen and oxygen isotopes distribution in lake ice body.
Stable isotopes have been used to identify the characteristics of precipitation, evaporation, basin hydrology, and residence times. However, lakes in the cold regions are usually covered by ice for 5-6 months. To get a better understanding of stable isotopes characteristics and indications in lake ice bodies, ice and water were sampled during the icebound season in both the ice and water bodies in Dali Lake, and deuterium, oxygen-18 total nitrogen (TN), and the major ions were analyzed. The results showed that deuterium and oxygen-18 compositions (δD-δ¹⁸O) compositions in the ice body were greater than in the water body beneath, scattered on a straight line, and deviating downward from the global meteoric water line in the top right. The ice profile showed that the δD-δ¹⁸O compositions increased from the ice surface downward and decreased near to the bottom. In contrast, the TN and the major ions in the ice decreased from the ice surface downward and increased near to the bottom, meaning that the concentrations of δ¹⁸O had a negative correlation with the concentrations of TN and major ions. These indicated that stable isotopes can be used for tracing the nutriment and ion transport processes in the ice body.
Research on the Evolution of Dali Lake Area Based on the Remote Sensing Technology
In order to explore lake shrinking in cold and arid regions of China,regarding Dali Lake as the research object,this paper uses the image data of landsat 5TM in 1999,2001,2003,2007and 2010,applying ENVI4.7and ArcGIS9.3to analyze and deal with selected image.At last the area variation about 10years is obtained.the local evaporation capacity and precipitation data are combined to analyze the reason of lake area change.The results show that band 742color composite image features color contrast is most intense,and the effects of area extracting are closest to actual experiences.So the extracted area project in Dali Lake is all based on RGB=742to compose image.For 11years,the area of Dali Lake totally presents decline trend year by year.In 1999,the area is 213.54km2 while it is 188.48km2 in 2010and the area decrease by 25.06km2.Especially 2003years later,reducing speed is greater.By analyzing the meteorological data,evaporation is about 1.8times of precipitation.The main cause is years of drought,evaporation is much more than supplementary amount.And overgrazing ecological environment destruction around lakes caused by overgrazing is also making lakes shrink.
The Provincial Centre at Camulodunum: Towards an Historical Context
Present assessment of the provincial enclosure at Camulodunum, more particularly how far it can be compared to the standard picture of similar centres elsewhere, is inevitably constrained by the limited evidence at our disposal. With no numismatic sources to draw on and in the absence of a single record of the provincial priesthood — a striking void that calls for comment — documentary testimony is restricted to what can be made of two passages in the literary authorities. The first, a notorious sneer in Seneca's Apocolocyntosis (VIII.3), tells only that a temple of some sort was associated somehow with the emperor Claudius. The second text, an obscure allusion in Tacitus, is at first sight no more enlightening but, on closer analysis, the phrase templum Divo Claudio constitutum (Ann. xiv.31) yields the invaluable inference that the temple was to the deified, not the living Claudius; in which case construction must have been begun in a.d. 54 or later. Archaeological data throw no light on the origins of the temple or of the precinct in which it stood but exploration has steadily enlarged our knowledge of the site itself, and understanding of the remains has now reached the stage at which, for all its puzzling lacunae, the centre is as well known in some ways as the triple-tiered complex at Tarraco, the provincial enclave of Hispania Citerior. We have arrived at the point where the British sanctuary and its counterparts on the Continent can be mutually illuminating.