Editorial     

Karl Rinner 《Marine Geodesy》2013,36(3):203-205

The long‐term mean sea level in the Baltic Sea is investigated using the coupled three‐basin model constructed by Carlsson (1997). The model is forced by the observed sea level in the Kattegat, the freshwater supply, horizontal air pressure and density gradients, and the wind stress. Both the seasonal variations and the slope of the mean sea level are investigated and compared with the results of another oceanographic model (Lisitzin, 1962) and a geodetic model (Ekman &; Mäkinen, 1996). In the geodetic model an unofficial height system, NH60, is used, and one part of the investigation is to find out whether this height system is useful for oceanographers. The estimated mean sea level difference between the northern and the southern parts of the Baltic Sea are: 17.1 cm (the present model), 26 cm (Lisitzin's model), and 18.3 cm (the geodetic model). It is concluded that the mean sea level difference between the northern and southern parts of the Baltic Sea is due mainly to horizontal variations of density and air pressure, and that the height system NH60 is suitable for oceanographie applications.  相似文献   

Fe and Al oxides distribution in some ultisols and inceptisols of southeastern Nigeria in relation to soil total phosphorus   总被引：3，自引：1，他引：2  

Charles A. Igwe  Mehdi Zarei  Karl Stahr 《Environmental Earth Sciences》2010,60(5):1103-1111

Ten highly weathered soils in southeastern Nigeria were sampled from their typical A and B horizons for analyses. The objectives were to determine the different forms of Fe and Al oxides in the soils and relating their occurrence to phosphate availability and retention in the soils. The soils are deep and often physically degraded but are well drained and coarse in the particle size distribution. They are mostly dominated by kaolinite in their mineralogy with very high values of SiO₂. The soils are acidic with low soil organic carbon (SOC) contents. The elements in the exchange complex are also low thus reflecting in the low CEC of the soil. Available phosphorus (P) in the soils are generally low while total P ranged from 157 to 982 mg kg⁻¹ with an overall average of 422 mg kg⁻¹. Total Fe in the soil is highest and their order represented as follows: Fe_t > Fe_d > Fe_ox ≥ Fe_p. The pyrophosphate extractable Fe was always higher in the top soil than in the subsoil and was attributed to the fact that these forms of Fe are associated with organic matter which is more abundant in topsoil than in subsoil. Like in Fe forms, the order of Al occurrence could generally be presented as; Al_t > Al_d > Al_ox > Al_p. More Fe and Al oxides in the soils are strongly crystalline while a small quantity is poorly crystalline Fe forms. The amorphous forms of both Fe and Al are very low in the soils when compared with the crystalline forms. The oxides that show very strong affinity to total P are Fe_d–Fe_ox, Fe_d, Al_d, Fe_t, Fe_ox and Al_ox/Al_d. To overcome this problem of P retention in the soil, we recommend constant liming of these soils to neutralize them, application of organic matter and of high dosage of phosphate fertilizer to the soils.  相似文献   

QUATERNARY GROWTH FOLDS IN THE JIUXI BASIN AT THE NORTHEASTERN MARGIN OF THE QINGHAI—XIZANG PLATEAU     

Chen Jie  Karl  |Heinz Wyrwoll  Annette George  Lu Yanchou 《地学前缘》2000,(Z1)

QUATERNARY GROWTH FOLDS IN THE JIUXI BASIN AT THE NORTHEASTERN MARGIN OF THE QINGHAI—XIZANG PLATEAUgrants 49732 0 90and 496 0 2 0 36fromtheNSFofChina  相似文献   

1951年以来奥地利人口变化的空间特征     

卡尔·胡萨  刘岩  亚历山大·威斯保尔  海尔姆特·沃施莱格 《地理学报》2006,61(6):563-573

根据1951-2001年奥地利人口调查统计数据,分析了近50年来奥地利人口变化的时空间规律,以及人口变化中的增长区和下降区的区域配置等特征,并建立人口变化模式。研究表明：20世纪后半叶奥地利经历了其他欧盟国所表现出的城市化、城市郊区化和人口老龄化的各个过程。特别是城市老龄化表现更为突出,据预测推算,到2035年奥地利将会有1/3的人口超过60岁。在分析过程中,不仅应用了行政区划的区域方法,而且也依据土地利用的经济性质,在“土地经济生产小区”的基底上,对人口的变化规律进行了更为深入的透视。研究结果显示：奥地利西部阿尔卑斯山地中的城市区域人口增长幅度最大。沿着捷克和斯洛伐克边界伸展的北部和东北部区域是最严重的人口缺失地区。而奥地利阿尔卑斯山地东部的一些早期产业都市及其郊区,乃至更远一些的南部和东南部的老工业区域,目前由于普遍存在着经济的困境,也直接导致了这些地区人口的下降。但奥地利未来的总人口趋势将持续稳定。  相似文献   

The queen conch fishery on Pedro Bank, Jamaica: discovery, development, management     

Karl A. Aiken  G. Andre Kong  Stephen Smikle  Robin Mahon  Richard Appeldoorn 《Ocean & Coastal Management》1999,42(12):67

The history, methods, problems and regulation of fishing of the last remaining large queen conch resource in the world, located on a Jamaican fishing bank, are examined. The fishery activities for the queen conch, Strombus gigas Linnaeus are briefly described with the main activities in the industrial sector which produce the bulk of the harvest, which is exported. There are a few large producers harvesting the single major fishing ground of Pedro Bank, southwest of Kingston. These fishers harvested at least 1500 t annually between 1992 and 1998. Management is by licensing, individual quotas and a close season from July to October. Regulations related to CITES are thought to greatly assist in making licensed harvesters provide catch data to the Fisheries Division. The industrial operators have provided funding to undertake stock assessment studies in 1994 and again in 1997. We highlight the focus on management on a participatory consensual approach with meetings with all players in the industry. The conch fishery is thought to be one of the few areas of the Jamaica fishery where there is close and successful collaboration between fishers and the Fisheries Division. It provides an example of how rapid, precautionary, participatory action can provide an adequate basis for management until more definitive scientific information becomes available. The status of the conch fishery is thought to be sustainable at present, once reductions are made to the annual quota.  相似文献   

Flow localization in fissure eruptions     

Jonathan J. Wylie  Karl R. Helfrich  Brian Dade  John R. Lister  John F. Salzig 《Bulletin of Volcanology》1999,60(6):432-440

 During a basaltic fissure eruption heat transfer from the hot magma to the surrounding rock causes a dramatic increase in the magmatic viscosity and solidification at the margins. Both viscosity contrast and solidification can amplify initial variations in the flow rate and lead to localization of the flow along the strike of the fissure. However, for typical parameters, amplification driven by solidification is slower and significantly weaker than amplification driven by viscosity variations. In fact, for the parameters examined, the amplification due to solidification is so weak that its effect is almost insignificant, whereas viscosity variation provides a strong active mechanism for flow localization. Laboratory experiments illustrate viscous localization and suggest that this mechanism is robust. The dependence of viscosity on temperature can cause a small change in the pressure of the magma chamber to lead to a large jump in the flow rate of magma through the fissure. Received: 13 March 1998 / Accepted: 27 September 1998  相似文献   

Comparative analysis of Lake Periphyton communities using high performance liquid chromatography (HPLC) and light microscope counts   总被引：1，自引：0，他引：1  

Karl E. Havens  Alan D. Steinman  H. J. Carrick  J. William Louda  Nancy M. Winfree  Earl W. Baker 《Aquatic Sciences - Research Across Boundaries》1999,61(4):307-322

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Climate Extremes: Selected Review and Future Research Directions   总被引：10，自引：0，他引：10  

Thomas R. Karl  David R. Easterling 《Climatic change》1999,42(1):309-325

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Effects of a high rise building on wind flow and beach characteristics at Atlantic City, NJ, USA     

Karl F. Nordstrom  Nancy L. Jackson 《Ocean & Coastal Management》1998,39(3):245-263

This study assesses the effects of a high rise building on the beach and dune at an intensively developed shoreline through field investigation of geomorphological and sedimentological characteristics and wind tunnel investigation of wind speed and direction. Results indicate that wind speed is increased close to the building, where wind is often deflected to a more onshore direction. Obliquely offshore northwesterly winds are the most dramatically altered and cause onshore flows (with pronounced upward flows) in the landward portion of the beach near the building. Onshore deflections in wind direction cause besanding of the boardwalk and create highly localized scour and deposition zones. A dune on the backbeach breaks up zones of sediment transport and scour and diminishes the likelihood that scour areas will cause increased hazard to landward buildings as a result of flooding. Generic large-scale studies are required to develop criteria for communities to use to specify optimum dimensions, locations and shapes of landforms that are modified or created by high rise structures.  相似文献   

Validation of official erosion modelling based on high‐resolution radar rain data by aerial photo erosion classification          下载免费PDF全文

Franziska Katharina Fischer  Michael Kistler  Robert Brandhuber  Harald Maier  Melanie Treisch  Karl Auerswald 《地球表面变化过程与地形》2018,43(1):187-194

The universal soil loss equation (USLE) is the most frequently applied erosion prediction model and it is also implemented as an official decision‐making instrument for agricultural regulations. The USLE itself has been already validated using different approaches. Additional errors, however, arise from input data and interpolation procedures that become necessary for field‐specific predictions on a national scale for administrative purposes. In this study, predicted event soil loss using the official prediction system in Bavaria (Germany) was validated by comparison with aerial photo erosion classifications of 8100 fields. Values for the USLE factors were mainly taken from the official Bavarian high‐resolution (5 × 5 m²) erosion cadastre. As series of erosion events were examined, the cover and management factor was replaced by the soil loss ratio. The event erosivity factor was calculated from high‐resolution (1 × 1 km², 5 min), rain gauge‐adjusted radar rain data (RADOLAN). Aerial photo erosion interpretation worked sufficiently well and average erosion predictions and visual classifications correlated closely. This was also true for data broken down to individual factors and different crops. There was no reason to assume a general invalidity of the USLE and the official parametrization procedures. Event predictions mainly suffered from errors in the assumed crop stage period and tillage practices, which do not reflect interannual and farm‐specific variation. In addition, the resolution of radar data (1 km²) did not seem to be sufficient to predict short‐term erosion on individual fields given the strong spatial gradients within individual rains. The quality of the input data clearly determined prediction quality. Differences between USLE predictions and observations are most likely caused by parametrization weaknesses but not by a failure of the model itself. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献