The exceptional growth of the Arctic charr,Salvelinus alpinus (L.) in Lake Geneva

The growth rate of the Arctic charr,Salvelinus alpinus (L.), is exceptionally high in Lake Geneva; one of the highest every recorded. This can be explained by three factors: (1) the Arctic charr of Lake Geneva is the most southerly indigenous population in the world, (2) the trophic resources are important because of the eutrophication of the lake, (3) the fish density is low.     

空间直角坐标直接计算高斯平面直角坐标公式

本文首先导出了由空间直角坐标直接解算大地纬度的精确而简明的实用公式。在此基础上，导出了由空间直角坐标直接计算高斯平面直角坐标公式。     

云南天文台时纬残差与昆明周围强震

一、引言 1985年11月在印度新德里举行的第19届IAU大会地球自转委员会的决议中指出,经典天体测量的时纬结果可用于研究地球物理现象,如地方垂线变化与地震活动性的预测等。在我国,1978年李致森、张国栋等首先提出时纬残差异常与地震的相关性。     

Latitudinal patterns and influencing factors of soil humic carbon fractions from tropical to temperate forests

Soil humic carbon is an important component of soil organic carbon (SOC) in terrestrial ecosystems. However, no study to date has investigated its geographical patterns and the main factors that influence it at a large scale, despite the fact that it is critical for exploring the influence of climate change on soil C storage and turnover. We measured levels of SOC, humic acid carbon (HAC), fulvic acid carbon (FAC), humin carbon (HUC), and extractable humus carbon (HEC) in the 0–10 cm soil layer in nine typical forests along the 3800-km North-South Transect of Eastern China (NSTEC) to elucidate the latitudinal patterns of soil humic carbon fractions and their main influencing factors. SOC, HAC, FAC, HUC, and HEC increased with increasing latitude (all P<0.001), and exhibited a general trend of tropical < subtropical < temperate. The ratios of humic C fractions to SOC were 9.48%–12.27% (HAC), 20.68%–29.31% (FAC), and 59.37%–61.38% (HUC). Climate, soil texture, and soil microbes jointly explained more than 90% of the latitudinal variation in SOC, HAC, FAC, HEC, and HUC, and interactive effects were important. These findings elucidate latitudinal patterns of soil humic C fractions in forests at a large scale, and may improve models of soil C turnover and storage.     

2005年6月东亚夏季风活动异常及其影响机制初步分析

应用欧洲中心（ECMWF）N日08时客观分析资料、中国测站降水资料、OLR资料和NCEP2再分析资料以及国家气象中心提供的1976～2006年的逐日西太平洋副热带高压脊线位置，利用合成分析、小波分析和带通滤波等方法，初步分析了2005年东亚夏季风的活动特征和影响机制。结果发现2005年6月东亚夏季风活动出现明显异常，其中31～32候季风前沿异常停留在南海-菲律宾一带以及华南西部，33～35候季风前沿停滞在华南地区，较常年明显偏南，造成了我国华南洪涝；36候季风前沿跳至黄淮地区，导致长江空梅、黄淮地区多雨。进一步研究发现西太平洋副热带高压和中高纬槽脊活动异常及热带和中高纬度低频振荡是导致2005年6月东亚夏季风异常的主要原因。     

Generalization of the Lambert–Lagrange projection

The Lagrange projection represents conformally the terrestrial globe within a circle. This is achieved by compressing the latitude and longitude and by applying the new coordinates into the equatorial stereographic projection. The same concept can be generalized to any conformal projection, although the application of this technique to other analytical functions is less known. In this work, the general Lambert–Lagrange projection formula is proposed and the application of the modified coordinates is discussed on projections: stereographic, conformal conic and Gauss–Schreiber. In general, the results are merely a curiosity, except for the case of Gauss–Schreiber, where the use of coordinates with altered scale can be applied in the optimization of conformal projections.     

Change detection for 3D vector data: a CGA-based Delaunay–TIN intersection approach

In this paper, conformal geometric algebra (CGA) is introduced to construct a Delaunay–Triangulated Irregular Network (DTIN) intersection for change detection with 3D vector data. A multivector-based representation model is first constructed to unify the representation and organization of the multidimensional objects of DTIN. The intersection relations between DTINs are obtained using the meet operator with a sphere-tree index. The change of area/volume between objects at different times can then be extracted by topological reconstruction. This method has been tested with the Antarctica ice change simulation data. The characteristics and efficiency of our method are compared with those of the Möller method as well as those from the Guigue–Devillers method. The comparison shows that this new method produces five times less redundant segments for DTIN intersection. The computational complexity of the new method is comparable to Möller’s and that of Guigue–Devillers methods. In addition, our method can be easily implemented in a parallel computation environment as shown in our case study. The new method not only realizes the unified expression of multidimensional objects with DTIN but also achieves the unification of geometry and topology in change detection. Our method can also serve as an effective candidate method for universal vector data change detection.     

Environmental assessment from the sedimentary record of high-latitude fiords

The sedimentary record of fiords at high latitude where global change may be occurring earliest and will be greatest has the potential for assessment of environmental change at both low resolution (the scale of millennia) and high resolution (decadal to less than daily). Unlike the lacustrine record which has been used very successfully in these studies, the sedimentary processes and thus the sedimentary deposits of fiords differ (1) in the role of salt water in inhibiting mixing and promoting flocculation, and through the role of sea-ice, (2) in the exchange of mass and energy with the much larger ocean beyond, and (3) in the role of benthic biota in the sedimentary environment. The work reviewed in this paper shows that fiord sediments are being used to assess sedimentary and oceanic processes, as well as glacial, periglacial and geomorphic history, and that they are important proxies for long-term climate and hydrology. Recommendations for advancing this work include long-term monitoring of conditions in fiords and their drainage basins so that the transfer relations can be more solidly constructed from the proxy of fiord sediment. Integration of results from fiords in opposite polar latitudes, and among proxies especially from lacustrine and ice-core records will produce valuable insights. Assessment of the range of conditions in fiords from the most polar to temperate regions is important to building models of their processes and understanding of the paleoenvironmental signals that can be interpreted from each type.     

Abrupt vegetation changes during the last glacial to Holocene transition in mid‐latitude South America

A pollen record from the Huelmo site (ca. 41°30′S) shows that vegetation and climate changed at millennial time‐scales during the last glacial to Holocene transition in the mid‐latitude region of western South America. The record shows that a Nothofagus parkland dominated the landscape between 16 400 and 14 600 ¹⁴C yr BP, along with Magellanic Moorland and cupressaceous conifers. Evergreen North Patagonian rainforest taxa expanded in pulses at 14 200 and 13 000 ¹⁴C yr BP, following a prominent rise in Nothofagus at 14 600 ¹⁴C yr BP. Highly diverse, closed canopy rainforests dominated the lowlands between 13 000 and 12 500 ¹⁴C yr BP, followed by the expansion of cold‐resistant podocarps and Nothofagus at ca. 12 500 and 11 500 ¹⁴C yr BP. Local disturbance by fire favoured the expansion of shade‐intolerant opportunistic taxa between 10 900 and 10 200 ¹⁴C yr BP. Subsequent warming pulses at 10 200 and 9100 ¹⁴C yr BP led to the expansion of thermophilous, summer‐drought resistant Valdivian rainforest trees until 6900 ¹⁴C yr BP. Our results suggest that cold and hyperhumid conditions characterised the final phase of the Last Glacial Maximum (LGM), between 16 400 and 14 600 ¹⁴C yr BP. The last ice age Termination commenced with a prominent warming event that led to a rapid expansion of North Patagonian trees and the abrupt withdrawal of Andean ice lobes from their LGM positon at ca. 147 000 ¹⁴C yr BP. Hyperhumid conditions prevailed between 16 400 and 13 000 ¹⁴C yr BP, what we term the ‘extreme glacial mode’ of westerly activity. This condition was brought about by a northward shift and/or intensification of the southern westerlies. The warmest/driest conditions of the last glacial–interglacial transition occurred between 9100 and 6900 ¹⁴C yr BP. During this period, the westerlies shifted to an ‘extreme interglacial mode’ of activity, via a poleward migration of stormtracks. Our results indicate that a highly variable climatic interval lasting 5500 ¹⁴C years separate the opposite extremes of vegetation and climate during the last glacial‐interglacial cycle, i.e. the end of the LGM and the onset of the early Holocene warm and dry period. Copyright © 2003 John Wiley & Sons, Ltd.     

ZONALITY OF DISTRIBUTION OF PHYSICO-GEOGRAPHICAL ZONES IN CHINA

With the methods of regression analysis and trend surface analysis, taking the bottom and top lines of dark conifer forest, bottom line of permafrost and the snowline of the latest glaciation in China as examples, this paper discusses the zonality regulaties of the distribution of physico-geographical zones in China. (1) Latitude zonality obeys the mathematical model of normal frequency distribution, being approximate to descending straightly within the latitude of China. (2) Longitude zonality shows that the elevation of physico-geographical zone rises straightly with the distance to east coast. (3) The combination of latitude and longitude zonalities appears a plane inclining from SSW to NNE. The decline of physico-geographical zone resembles a semiellipse- sphere inclining from the Qinghai-Xizang (Tibet) Plateau to northeast China, reflecting the effect of relief. (5) Physico-geographical zonation depends on the combination of hydrothermal conditions. Thus the factors influencing the distribution reg