Le complexe volcano-plutonique de la Vlǎdeasa (Roumanie)deasa (Roumanie)     

D. Giusca  G. Istrati  A. Stefan 《Bulletin of Volcanology》1969,33(4):1118-1127

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On the energy content of the atmosphere     

Stefan L. Hastenrath 《Pure and Applied Geophysics》1969,75(1):268-277

Summary Vertical profiles of the content of sensible heat, potential energy, and latent heat in the atmosphere between 1000 and 100 mb, during January and July, are derived for the latitude circles 0, 10, 20, 30, 40, 50, and 60°N. Contrasts between oceans and continents are found to vary significantly with latitude and season.

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Zusammenfassung Vertikalprofile des Gehalts an fühlbarer Wärme, potentieller Energie und latenter Wärme in der Atmosphäre zwischen 1000 and 100 mb werden für Januar und Juli und die Breitenkreise 0, 10, 20, 30, 40, 50, und 60°N abgeleitet. Gegensätze zwischen Land und See ändern sich mit geographischer Breite und Jahreszeit.

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A. Winkler und V. Hermaden-Kapfenstein 《International Journal of Earth Sciences》1955,43(1):175

Ohne Zusammenfassung  相似文献   

Water balance components estimation under scenarios of land cover change in the Vea catchment,West Africa     

Isaac Larbi  Emmanuel Obuobie  Anne Verhoef  Stefan Julich  Karl-Henz Feger  Aymar Yaovi Bossa 《水文科学杂志》2020,65(13):2196-2209

ABSTRACT

The need for a detailed investigation of the Vea catchment water balance components cannot be overemphasized due to its accelerated land-cover dynamics and the associated impacts on the hydrological processes. This study assessed the possible consequences of land-use change scenarios (i.e. business as usual, BAU, and afforestation for the year 2025) compared to the 2016 baseline on the Vea catchment’s water balance components using the Soil and Water Assessment Tool (SWAT) model. The data used include daily climate and discharge, soil and land use/land cover maps. The results indicate that the mean annual water yield may increase by 9.1% under the BAU scenario but decrease by 2.7% under the afforestation scenario; actual evapotranspiration would decrease under BAU but increase under afforestation; and groundwater recharge may increase under both scenarios but would be more pronounced under the afforestation scenario. These outcomes highlight the significance of land-cover dynamics in water resource management and planning at the catchment.  相似文献   

Big Earth data: disruptive changes in Earth observation data management and analysis?     

Martin Sudmanns  Dirk Tiede  Stefan Lang  Helena Bergstedt  Georg Trost  Hannah Augustin 《International Journal of Digital Earth》2020,13(7):832-850

ABSTRACT

Turning Earth observation (EO) data consistently and systematically into valuable global information layers is an ongoing challenge for the EO community. Recently, the term ‘big Earth data’ emerged to describe massive EO datasets that confronts analysts and their traditional workflows with a range of challenges. We argue that the altered circumstances must be actively intercepted by an evolution of EO to revolutionise their application in various domains. The disruptive element is that analysts and end-users increasingly rely on Web-based workflows. In this contribution we study selected systems and portals, put them in the context of challenges and opportunities and highlight selected shortcomings and possible future developments that we consider relevant for the imminent uptake of big Earth data.  相似文献   

Evidence for chemical evolution in spectra of high redshift galaxies     

Dörte Mehlert  Stefan Noll  Immo Appenzeller 《Astrophysics and Space Science》2003,284(2):437-442

Using a sample of 57 VLT FORS spectra in the redshift range 1.37< z < 3.40 and a comparison sample with 36 IUE spectra of local ( ) starburst galaxies we derive CIV equivalent width values and estimate metallicities of starburst galaxies as a function of redshift. Assuming that a calibration of the CIV equivalent widths in terms of the metallicity based on the local sample of starburst galaxies is applicable to high-z objects, we find a significant increase of the average metallicities from about 0.16 Z _⊙ at the cosmic epoch corresponding to z ≈ 3.2 to about 0.42 Z _⊙ at z ≈ 2.3. A significant further increase in metallicity during later epochs cannot be detected in our data. Compared to the local starburst galaxies our high-redshift objects tend to be overluminous for a given metallicity. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Mitigating the Rate and Extent of Global Warming   总被引：1，自引：0，他引：1  

Stefan Rahmstorf  Andrey Ganopolski 《Climatic change》2002,52(3):255-262

Editorial Introduction

Mitigating the Rate and Extent of Global Warming  相似文献   

Integrated surface–groundwater flow modeling: A free-surface overland flow boundary condition in a parallel groundwater flow model     

Stefan J. Kollet  Reed M. Maxwell 《Advances in water resources》2006

Interactions between surface and groundwater are a key component of the hydrologic budget on the watershed scale. Models that honor these interactions are commonly based on the conductance concept that presumes a distinct interface at the land surface, separating the surface from the subsurface domain. These types of models link the subsurface and surface domains via an exchange flux that depends upon the magnitude and direction of the hydraulic gradient across the interface and a proportionality constant (a measure of the hydraulic connectivity). Because experimental evidence of such a distinct interface is often lacking in field systems, there is a need for a more general coupled modeling approach.  相似文献   

Restoration of submerged vegetation in shallow eutrophic lakes – A guideline and state of the art in Germany     

Sabine Hilt  Elisabeth M. Gross  Michael Hupfer  Harald Morscheid  Jens Mhlmann  Arnulf Melzer  Jens Poltz  Stefan Sandrock  Eva-Maria Scharf  Susanne Schneider  Klaus van de Weyer 《Limnologica》2006,36(3):155-171

One of the most serious problems caused by eutrophication of shallow lakes is the disappearance of submerged macrophytes and the switch to a turbid, phytoplankton-dominated state. The reduction of external nutrient loads often does not result in a change back to the macrophyte-dominated state because stabilising mechanisms that cause resilience may delay a response. Additional internal lake restoration measures may therefore be needed to decrease the concentration of total phosphorus and increase water clarity. The re-establishment of submerged macrophytes required for a long-term stability of clear water conditions, however, may still fail, or mass developments of tall-growing species may cause nuisance for recreational use. Both cases are often not taken into account when restoration measures are planned in Germany, and existing schemes to reduce eutrophication consider the topic inadequately. Here we develop a step-by-step guideline to assess the chances of submerged macrophyte re-establishment in shallow lakes. We reviewed and rated the existing literature and case studies with special regard on (1) the impact of different internal lake restoration methods on the development of submerged macrophytes, (2) methods for the assessment of natural re-establishment, (3) requirements and methods for artificial support of submerged macrophyte development and (4) management options of macrophyte species diversity and abundance in Germany. This guideline is intended to help lake managers aiming to restore shallow lakes in Germany to critically asses and predict the potential development of submerged vegetation, taking into account the complex factors and interrelations that determine their occurrence, abundance and diversity.  相似文献   

Spatiotemporal analysis of precipitation trends in the Yangtze River catchment   总被引：2，自引：2，他引：2  

Stefan Becker  Marco Gemmer  Tong Jiang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,20(6):435-444

Precipitation trends in the Yangtze River catchment (PR China) have been analyzed for the past 50 years by applying the Mann-Kendall trend test and geospatial analyses. Monthly precipitation trends of 36 stations have been calculated. Significant positive trends at many stations can be observed for the summer months, which naturally show precipitation maxima. They were preceded and/or followed by negative trends. This observation points towards a concentration of summer precipitation within a shorter period of time. The analysis of a second data set on a gridded basis with 0.5° resolution reveals trends with distinct spatial patterns. The combination of classic trend tests and spatially interpolated precipitation data sets allows the spatiotemporal visualization of detected trends. Months with positive trends emphasize the aggravation of severe situation in a region, which is particularly prone to flood disasters during summer. Reasons for the observed trends were found in variations in the meridional wind pattern at the 850 hPa level, which account for an increased transport of warm moist air to the Yangtze River catchment during the summer months.  相似文献