全文获取类型
收费全文 | 82篇 |
免费 | 1篇 |
专业分类
测绘学 | 7篇 |
大气科学 | 18篇 |
地球物理 | 18篇 |
地质学 | 16篇 |
海洋学 | 16篇 |
天文学 | 3篇 |
自然地理 | 5篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 7篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 1篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有83条查询结果,搜索用时 46 毫秒
61.
The data of the CTD survey conducted in the Denmark Strait and Irminger Sea in May–June 2009 are used to calculate the vertical profiles of the turbulent overturning scale, which are then used to estimate the dissipation and entrainment rates in the overflow plume. The resulting estimates of the entrainment rate varied widely from 2 × 10–7 to 7 × 10–3 m/s. It is shown that such a wide range of entrainment rates is caused by the intermittency of turbulence. Large turbulent overturning at the interface of the Denmark Strait overflow plume is detected on the vertical temperature, salinity, and potential density profiles. 相似文献
62.
This is a paper from the Swedish research project ‘The coastal zone—scientific criteria for planners’. The goal has been to establish simple, general scientific methods for management of Swedish coastal waters. In this paper the focus is on a set of empirical data from 21 so-called type areas and on the exchange of surface water. The working hypothesis has been that the water retention (or residence) time is regulated by the morphometry. The theory has been verified. It has been shown that the water retention time can be determined from a formula based on only two key morphometric parameters, the exposure and the mean coastal width. It provides an 86% degree of explanation (r2=0·86) of the variation in empirically determined retention times and can be physically linked to the basic mass balance equation. The formula is valid for the bioproductive season (May–Oct.) and for small (1–100 km2) Swedish coastal areas. It cannot be directly applied to areas affected by heavy tides. 相似文献
63.
The Arctic Ocean-Nordic Seas thermohaline system 总被引:2,自引:0,他引:2
64.
Leontine E. Becking Daniel F. R. Cleary Nicole J. de Voogd Willem Renema Manon de Beer Rob W. M. van Soest & Bert W. Hoeksema 《Marine Ecology》2006,27(1):76-88
In order to preserve diversity it is essential to understand how assemblages change across space. Despite this fact, we still know very little about how marine diversity is spatially distributed, especially among lesser‐studied invertebrate taxa. In the present study beta‐diversity patterns of sea urchins, sponges, mushroom corals and larger foraminifera were assessed in the Spermonde Archipelago (Indonesia). Using ordinations we showed that the inshore zone (<5 km offshore), midshore zone (5 < x < 30 km offshore) and distance offshore zone (>30 km offshore) all contained distinct assemblages of sponges and corals, while only foraminifera assemblages from the inshore (<5 km offshore) zone were distinct. There was a significant spatial pattern of community similarity for all taxa surveyed, but this pattern proved to be wholly related to environmental variables for sponges and foraminifera, and primarily for mushroom corals and sea urchins. The lack of a pure spatial component suggests that these taxa may not be dispersal limited within the spatial scales of this study (c. 1600 km2). The analyses of the corals and foraminifera were additionally tested at two spatial scales of sampling. Both taxa were primarily associated with local‐scale environmental variables at the local scale and larger‐scale variables at the larger scale. Mean inter‐plot similarity was also higher and variation lower at the larger scale. The results suggest that substantial variation in similarity can be predicted using simple locally assessed environmental variables combined with remotely sensed parameters. 相似文献
65.
In this paper, we present results of simulationexperiments with the TIME-model on the issue ofmitigation strategies with regard to greenhouse gases.The TIME-model is an integrated system dynamics worldenergy model that takes into account the fact that the systemhas an inbuilt inertia and endogenouslearning-by-doing dynamics, besides the more commonelements of price-induced demand response and fuelsubstitution. First, we present four scenarios tohighlight the importance of assumptions on innovationsin energy technology in assessing the extent to whichCO2 emissions have to be reduced. The inertia ofthe energy system seems to make a rise ofCO2 emissions in the short term almostunavoidable. It is concluded that for the populationand economic growth assumptions of the IPCC IS92ascenario, only a combination of supply- anddemand-side oriented technological innovations incombination with policy measures can bring the targetof CO2-concentration stabilization at 550 ppmv bythe year 2100 within reach. This will probably beassociated with a temporary increase in the overallenergy expenditures in the world economy. Postponingthe policy measures will be more disadvantageous,and less innovation in energy technology willhappen. 相似文献
66.
Jens Blotevogel Charles Pijls Bert Scheffer Jean-Paul de Waele Amy Lee Reggy van Poecke Nicolaas van Belzen Wim Staal 《Ground Water Monitoring & Remediation》2019,39(1):36-42
Electrochemical treatment is a promising emerging technology in which direct current is applied to drive the degradation of aqueous contaminants. Several bench-scale studies have demonstrated the capability of electrochemical oxidation to fully mineralize refractory organics such as pesticides and perfluorinated compounds. However, insights into large-scale design and field performance are critically lacking. Here, we designed six pilot-scale reactors and tested their performance and efficiency for the treatment of groundwater contaminated with 1,4-dioxane (1,4-DX) at concentrations exceeding 1000 mg/L. Anode surface area-normalized degradation rates increased with increasing potential applied, while the process was more energy-efficient per mass unit removed at low potentials. While not all 1,4-DX was completely mineralized, the detected ring-opening intermediates are known to be readily biodegradable. Analyses of potential by-products from chloride oxidation revealed the generation of chloromethanes and perchlorate at low mg/L concentrations. Towards the end of the 8.5-month pilot test, decreasing currents and degradation rates indicated progressing passivation of the electrodes, likely due to cathodic carbonate precipitation and/or poisoning by the uniquely high organic carbon load of this source zone groundwater. The findings of our study demonstrate that electrochemical groundwater remediation is a capable approach for the treatment of persistent organic pollutants. Our pilot-scale test provides practitioners with a basis for evaluating its efficiency under site-specific conditions and collecting critical performance metrics for technology scale-up. 相似文献
67.
68.
Jin Ba Noel S. Keenlyside Mojib Latif Wonsun Park Hui Ding Katja Lohmann Juliette Mignot Matthew Menary Odd Helge Otterå Bert Wouters David Salas y Melia Akira Oka Alessio Bellucci Evgeny Volodin 《Climate Dynamics》2014,43(9-10):2333-2348
A multi-model analysis of Atlantic multidecadal variability is performed with the following aims: to investigate the similarities to observations; to assess the strength and relative importance of the different elements of the mechanism proposed by Delworth et al. (J Clim 6:1993–2011, 1993) (hereafter D93) among coupled general circulation models (CGCMs); and to relate model differences to mean systematic error. The analysis is performed with long control simulations from ten CGCMs, with lengths ranging between 500 and 3600 years. In most models the variations of sea surface temperature (SST) averaged over North Atlantic show considerable power on multidecadal time scales, but with different periodicity. The SST variations are largest in the mid-latitude region, consistent with the short instrumental record. Despite large differences in model configurations, we find quite some consistency among the models in terms of processes. In eight of the ten models the mid-latitude SST variations are significantly correlated with fluctuations in the Atlantic meridional overturning circulation (AMOC), suggesting a link to northward heat transport changes. Consistent with this link, the three models with the weakest AMOC have the largest cold SST bias in the North Atlantic. There is no linear relationship on decadal timescales between AMOC and North Atlantic Oscillation in the models. Analysis of the key elements of the D93 mechanisms revealed the following: Most models present strong evidence that high-latitude winter mixing precede AMOC changes. However, the regions of wintertime convection differ among models. In most models salinity-induced density anomalies in the convective region tend to lead AMOC, while temperature-induced density anomalies lead AMOC only in one model. However, analysis shows that salinity may play an overly important role in most models, because of cold temperature biases in their relevant convective regions. In most models subpolar gyre variations tend to lead AMOC changes, and this relation is strong in more than half of the models. 相似文献
69.
Interdecadal North-Atlantic meridional overturning circulation variability in EC-EARTH 总被引:2,自引:2,他引:0
The Atlantic meridional overturning circulation (AMOC) in a 600?years pre-industrial run of the newly developed EC-EARTH model features marked interdecadal variability with a dominant time-scale of 50–60?years. An oscillation of approximately 2 Sverdrup (1?Sv?=?106?m3?s?1) is identified, which manifests itself as a monopole causing the overturning to simultaneously strengthen (/weaken) and deepen (/shallow) as a whole. Eight years before the AMOC peaks, density in the Labrador-Irminger Sea region reaches a maximum, triggering deep water formation. This density change is caused by a counterclockwise advection of temperature and salinity anomalies at lower latitudes, which we relate to the north-south excursions of the subpolar-subtropical gyre boundary and variations in strength and position of the subpolar gyre and the North Atlantic Current. The AMOC fluctuations are not directly forced by the atmosphere, but occur in a delayed response of the ocean to forcing by the North Atlantic Oscillation, which initiates “intergyre”-gyre fluctuations. Associated with the AMOC is a 60-year sea surface temperature variability in the Atlantic, with a pattern and timescale showing similarities with the real-world Atlantic Multidecadal Variability. This good agreement with observations lends a certain degree of credibility that the mechanism that is described in this article could be seen as representative of the real climate system. 相似文献
70.
We address possibilities of minimising environmental risks using statistical features of current-driven propagation of adverse
impacts to the coast. The recently introduced method for finding the optimum locations of potentially dangerous activities
(Soomere et al. in Proc Estonian Acad Sci 59:156–165, 2010) is expanded towards accounting for the spatial distributions of probabilities and times for reaching the coast for passively
advecting particles released in different sea areas. These distributions are calculated using large sets of Lagrangian trajectories
found from Eulerian velocity fields provided by the Rossby Centre Ocean Model with a horizontal resolution of 2 nautical miles
for 1987–1991. The test area is the Gulf of Finland in the northeastern Baltic Sea. The potential gain using the optimum fairways
from the Baltic Proper to the eastern part of the gulf is an up to 44% decrease in the probability of coastal pollution and
a similar increase in the average time for reaching the coast. The optimum fairways are mostly located to the north of the
gulf axis (by 2–8 km on average) and meander substantially in some sections. The robustness of this approach is quantified
as the typical root mean square deviation (6–16 km) between the optimum fairways specified from different criteria. Drastic
variations in the width of the ‘corridors’ for almost optimal fairways (2–30 km for the average width of 15 km) signifies
that the sensitivity of the results with respect to small changes in the environmental criteria largely varies in different
parts of the gulf. 相似文献