Scintillometer-Based Turbulent Fluxes of Sensible and Latent Heat Over a Heterogeneous Land Surface – A Contribution to Litfass-2003     

W. M. L. Meijninger  F. Beyrich  A. Lüdi  W. Kohsiek  H. A. R. De. Bruin 《Boundary-Layer Meteorology》2006,121(1):89-110

The performance of a combined large aperture scintillometer (LAS) and a millimetre wave scintillometer (MWS) for estimating surface fluxes of sensible and latent heat over natural landscape is investigated, using data gathered during LITFASS-2003. For this purpose the LAS–MWS system was installed in a moderate heterogeneous landscape over a path length of 4.7 km with an effective beam height of 43 m. The derived surface fluxes have been compared with aggregated eddy-covariance (EC) measurements. The fluxes of sensible and latent heat from the LAS–MWS combination, as well as sensible heat fluxes of the single LAS, agreed fairly well with the EC-based fluxes, considering the uncertainties of the similarity stability functions and observed energy imbalance.  相似文献   

The 1995 Kozani–Grevena (northern Greece) earthquake revisited: an improved faulting model from synthetic aperture radar interferometry     

Alexis Rigo  Jean-Bernard de Chabalier  Bertrand Meyer  Rolando Armijo 《Geophysical Journal International》2004,157(2):727-736

  相似文献   

The hydrochemistry of the inland waters of Argentina: a review     

Edmundo Drago  Rolando Quiros 《International Journal of Salt Lake Research》1995,4(4):315-325

The major ion chemistry of 639 aquatic localities in Argentina is presented and discussed. Salinities range from quite fresh (<3 g L^–1) to highly saline (>300 g L^–1); a variety of ion dominances occur but NaCl predominates in highly saline waters. The principal mechanisms controlling water chemistry are rock dominance and evaporation; atmospheric contributions are less important.  相似文献   

Toxicity and bioaccumulation of sulphadimethoxine inArtemia (Crustacea,Anostraca)     

L. Migliore  G. Brambilla  A. Grassitellis  G. Dojmi di Delupis 《International Journal of Salt Lake Research》1993,2(2):141-152

To evaluate the effects of sulphonamide pollution in marine and brackish systems, and to assess the utility of a recently proposed test protocol, sulphadimethoxine toxicity was measured using naupli and cysts of anArtemia species. Nauplii mortality, evaluated between 24 and 96 h, indicated a relatively high toxicity of sulphadimethoxine toArtemia (96 h LC₅₀= 19.5 mg L⁻¹). In addition, test on cysts demonstrated that a nominal concentration of 300 mg L⁻¹ sulphadimethoxine significantly depressed hatching. Toxicity could depend on the high bioaccumulation rate of sulphadimethoxine measured in the organisms. The role of these tests in assessing the environmental risks of intensive farming and in determining suitable standards to improve water quality criteria is discussed together with the possible utilization of bioaccumulatingArtemia as ‘medicated feed’.  相似文献   

Dependence of eelgrass (Zostera marina) light requirements on sediment organic matter in Massachusetts coastal bays: Implications for remediation and restoration     

W.J. Kenworthy  C.L. Gallegos  Charles Costello  Donald Field  Giuseppe di Carlo 《Marine pollution bulletin》2014

Using a calibrated bio-optical model we determined that the optical water quality conditions in several nitrogen-impaired embayments and in one unimpaired system were within the range of values known to support eelgrass growth. We also used the model to identify a range of light requirements for eelgrass (Zostera marina). Higher eelgrass light requirements, expressed as a percentage of surface-incident irradiance, corresponded with higher sediment organic matter content. These results corroborated findings by previous studies which indicate a generalized relationship: seagrasses growing in turbid conditions with poorer water and sediment quality have higher light requirements than those growing in less degraded conditions. The mechanistic reason for the variation in light requirements is still not completely explained and cannot be attributed to a single independent variable. Varying light requirement have important implications for eelgrass protection and should be considered when setting restoration targets for eelgrass in water quality and nitrogen remediation programs.  相似文献   

Probabilistic evaluation of the physical impact of future tephra fallout events for the Island of Vulcano,Italy     

Sebastien Biass  Costanza Bonadonna  Federico di Traglia  Marco Pistolesi  Mauro Rosi  Pierino Lestuzzi 《Bulletin of Volcanology》2016,78(5):37

A first probabilistic scenario-based hazard assessment for tephra fallout is presented for La Fossa volcano (Vulcano Island, Italy) and subsequently used to assess the impact on the built environment. Eruption scenarios are based upon the stratigraphy produced by the last 1000 years of activity at Vulcano and include long–lasting Vulcanian and sub-Plinian eruptions. A new method is proposed to quantify the evolution through time of the hazard associated with pulsatory Vulcanian eruptions lasting from weeks to years, and the increase in hazard related to typical rainfall events around Sicily is also accounted for. The impact assessment on the roofs is performed by combining a field characterization of the buildings with the composite European vulnerability curves for typical roofing stocks. Results show that a sub-Plinian eruption of VEI 2 is not likely to affect buildings, whereas a sub-Plinian eruption of VEI 3 results in 90 % of the building stock having a ≥12 % probability of collapse. The hazard related to long-lasting Vulcanian eruptions evolves through time, and our analysis shows that the town of Il Piano, located downwind of the preferential wind patterns, is likely to reach critical tephra accumulations for roof collapse 5–9 months after the onset of the eruption. If no cleaning measures are taken, half of the building stock has a probability >20 % of suffering roof collapse.  相似文献   

The density of extremely red objects around high-z radio-loud active galactic nuclei     

A. Cimatti  D. Villani  L. Pozzetti  S. di Serego Alighieri 《Monthly notices of the Royal Astronomical Society》2000,318(2):453-461

We present the results of a K -band imaging survey of 40 arcmin² in fields around 14 radio-loud active galactic nuclei (AGN), comprising six radio galaxies and eight quasars, with z >1.5. The survey, which is 80 per cent complete to K <19.2 mag and complemented by R -band imaging, aimed at investigating whether extremely red objects are present in excess around high- z AGN, and to study the environment of z >1.5 radio galaxies and radio-loud quasars. At 18< K <19 mag, the differential galaxy counts in our fields suggest a systematic excess over the general field counts. At K <19.2 mag we find an excess of galaxies with R − K >6 in comparison with the general field. Consistently, we also find that the R − K colour distribution of all the galaxies in the AGN fields is significantly redder than the colour distribution of the field galaxies. On the other hand, the distribution of the R − K colours is indistinguishable from that of galaxies taken from literature fields around radio-loud quasars at 1< z <2. We discuss the main implications of our findings and we compare the possible scenarios that could explain our results.  相似文献   

Oceanic response to Hurricane Irma (2017) in the Exclusive Economic Zone of Cuba and the eastern Gulf of Mexico     

Avila-Alonso  Dailé  Baetens  Jan M.  Cardenas  Rolando  De Baets  Bernard 《Ocean Dynamics》2020,70(5):603-619

Ocean Dynamics - An understanding of the oceanic response to tropical cyclones is of importance for studies on climate change, ecological variability and environmental protection. Hurricane Irma...  相似文献   

太沙基方程Laplace解     

张琦  王生志  徐大地 《地质与资源》2004,13(2):126-128,108

根据饱和土单向渗透固结的特殊规律,以外荷一次性施加,初始超静水压u₀等于常数,顶面透水,用底部超静水压力u在任意时刻为有限值这个事实,代替底部边界排、隔水条件等简化假定,作为简单情况下太沙基单向固结微分方程的初始和边界条件.对太沙基单向固结微分方程进行拉氏积分变换求解.得到超静水压力u、固结度U、平均固结度U结论式.客观地反映了土层固结过程中u、U、U,随Z、t的变化规律,且形式简洁,使用方便,有效可行.  相似文献   

Gravity contributions to the understanding of salt tectonics from the Jebel Cheid area (dome zone, Northern Tunisia)     

Imen Hamdi-Nasr  Mohamed Hédi Inoubli  Abdelhamid Ben Salem  Saïd Tlig  Abdelbaki Mansouri 《Geophysical Prospecting》2009,57(4):719-728

Detailed gravity measurements integrated with geological data were computed to constrain the mechanisms that were active during the emplacement of the Triassic evaporite-bearing folds of Jebel Cheid from the salt-dome zone in the Atlassic region. The gravity analysis consists in mapping the contrasting gravity responses: complete Bouguer anomaly, residual anomaly and derivative maps; the main results display a positive amplitude gravity anomaly as the response of Triassic evaporite bodies and important NE–SW-trending features at the boundaries between the Triassic outcrops and their enveloping strata. In contrast with gravity calculations of a salt dome structure usually resulting in negative gravity anomaly models, the Jebel Cheid clearly expresses a positive gravity anomaly; furthermore, this result is supported by synthetic gravity interpretation.  相似文献