A steady-state model of a cumulus cloud,describing phase transitions by kinetic equations. I. model pattern     

Ivana Nemešova  Dana Lakomá  Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1974,18(3):274-297

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The evaporation of liquid water in describing the dynamic aspects in a model of a convective cloud     

Ivana Nemešová  Reviewer O. Zikmunda 《Studia Geophysica et Geodaetica》1977,21(2):179-184

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On the entrainment in cumuli — A contribution to a case study     

Ivana Nemešová  Reviewer J. Bednář 《Studia Geophysica et Geodaetica》1988,32(1):101-113

Summary The case study presented here is related to the thermodynamic analysis of entrainment and mixing in a shallow cumuls layer. The fair weather situation on 9. 9. 1983, Voves, is characterized by a field of scattered cumuli of the same depths and by a towering isolated cumulus. The clouds were sampled. Two types of analysis were used, the Paluch analysis and saturation point analysis, both of them making use of conserved parameters and a mixing line structure. Both methods gave similar results. For the small cumuli, lateral entrainment prevailed up to the highest penetration level while in the isolated cumulus, cloud top entrainment was the dominant mixing mechanism.

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Climate Change Projections Based on GCM-Simulated Daily Data     

Ivana Nemešová  Jaroslava Kalová  Martin Dubrovský 《Studia Geophysica et Geodaetica》1999,43(2):201-222

Three-dimensional general circulation models (GCMs) are 'state-of-the-art' tools for projecting possible changes in climate. Scenarios constructed for the Czech Republic are based on daily outputs of the ECHAM-GCM in the central European region. Essential findings, derived from validating, procedures are summarized and changes in variables between the control and perturbed experiments are examined. The resulting findings have been used in selecting the most proper methods of generating climate change projections for assessing possible hydrological and agricultural impacts of climate change in selected exposure units. The following weather variables have been studied: Daily extreme temperatures, daily mean temperature, daily sum of global solar radiation, and daily precipitation amounts. Due to some discrepancies revealed, the temperature series for changed climate conditions (2×CO ₂ ) have been created with the help of temperature differences between the control and perturbed runs, and the precipitation series have been derived from an incremental scenario based on an intercomparison of the GCMs' precipitation performance in the region. Solar radiation simulated by the ECHAM was not available and, therefore, it was generated using regression techniques relating monthly means of daily extreme temperatures and global radiation sums. The scenarios published in the paper consist of monthly means of all temperatures, their standard deviations, and monthly means of solar radiation and precipitation amounts. Daily weather series, the necessary input to impact models, are created (i) by the additive or multiplicative modification of observed weather daily series or (ii) by generating synthetic time series with the help of a weather generator whose parameters have been modified in accord with the suggested climate change scenarios.  相似文献   

The Mangrove Ecosystem of the Ciénaga Grande de Santa Marta (Colombia): Observations on Regeneration and Trace Metals in Sediment     

Laura Perdomo  Ingo Ensminger  Luisa fernanda Espinosa  Carola Elster  Mnica Wallner-kersanach  Marie-Luise Schnetter 《Marine pollution bulletin》1999,37(8-12):393-403

Alteration of water flows and consequent hypersalinization caused the death of nearly 70% of mangroves at the Ciénaga Grande de Santa Marta, Colombia. Efforts to rehabilitate the ecosystem have been made through the construction of freshwater channels. Mangrove recovery was observed along a freshwater channel and at a small lagoon behind the beach ridge. Factors identified in this study influencing mangrove regeneration are: salinity of surface water, duration and height of flooding, leaching property of soils, dispersal of propagules and presence of fertile trees. Besides mangrove regeneration, a notable extension of freshwater plants was observed in the channel. Trace metal concentrations in sediments from the Magdalena River and its area of influence were investigated before the complete opening of the first channel. A relative comparison indicated that the highest concentrations of Cd, Cu, Ni and Zn were above international recommended limits. However, metal concentrations found in sediments at Clarín Channel did not affect the mangrove recovery.  相似文献   

Degradation of Styrene from Waste Gas Stream by Advanced Oxidation Processes     

Kamila Ko í  Martin Reli  Ivana Troppov  Tom&#x; Prostjovský  Radim ebrk 《洁净——土壤、空气、水》2019,47(8)

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A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups     

Domagoj Ruždjak  Roman Brajša  Davor Sudar  Ivica Skokić  Ivana Poljančić Beljan 《Solar physics》2017,292(12):179

The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differential-rotation parameters \(A\) and \(B\). These differential-rotation parameters were compared with the solar-activity level. We found that the Sun rotates more differentially at the minimum than at the maximum of activity during the epoch 1977?–?2016. An inverse correlation between equatorial rotation and solar activity was found using the recently revised sunspot number. The secular decrease of the equatorial rotation rate that accompanies the increase in activity stopped in the last part of the twentieth century. It was noted that when a significant peak in equatorial rotation velocity is observed during activity minimum, the next maximum is weaker than the previous one.  相似文献   

Population genetic structure of the endangered limpet Cymbula nigra in a temperate Northern hemisphere region: influence of palaeoclimatic events?     

Free Espinosa  Tomoyuki Nakano  Jose M. Guerra‐García  Jose C. García‐Gómez 《Marine Ecology》2011,32(1):1-5

Cymbula nigra (da Costa L, 1771) is the largest limpet in Europe and it is at present considered an endangered species. Nevertheless, its biology is poorly understood and there is a lack of knowledge about population genetic structure. A total of 61 C. nigra specimens were sampled and studied for a fragment of the mitochondrial gene cytochrome c oxidase subunit I. The low genetic diversity, the absence of geographic structure, the significant values reported by measures to test for a recent population expansion and a star‐shaped phylogeny pattern are here interpreted as forming a hypothesis concerning the influence of palaeoclimatic events in the genetic pool of limpets, considering also the information available on different limpet species.  相似文献   

Marine artificial micro‐reserves: a possibility for the conservation of endangered species living on artificial substrata     

José C. García‐Gómez  Carlos M. López‐Fé  Free Espinosa  José M. Guerra‐García  Georgina A. Rivera‐Ingraham 《Marine Ecology》2011,32(1):6-14

The installation of urban and commercial infrastructures on the coast has a severe impact on the marine environment. This impact is mostly negative but, simultaneously, some of the species that colonize artificial substrata (sometimes rare or threatened) find refuge in man‐made structures. The protection of endangered species is usually provided by marine protected areas or by laws that punish their damage or collection, but effective enclosure and custody must be achieved in the case of easily accessible intertidal species. We used the ferruginous limpet, Patella ferruginea, as a case study because it is the most endangered invertebrate in the Mediterranean. This species, which lives in the intertidal zone and is very accessible to people, is a free‐spawning, protandric hermaphrodite, highly dependent on population density and individual size for its reproductive success. Previous work by the authors found the species is especially abundant on artificial substrates on both shores of the Strait of Gibraltar, where people collect fewer of them. Spanish laws of coastal management do not allow the enclosure of the natural coastline, but artificial installations like harbour breakwaters may be closed or guarded, and visits for educational purposes may be carried out under control. The possibility of declaring some kind of environmental protection for these artificial areas would be a very helpful tool for conservation and management purposes. Protected individuals would grow larger and eventually produce exponentially more offspring, which could be transported by currents to adjacent habitats. Here we propose a protection concept for artificial sites termed Artificial Marine Micro‐Reserve (AMMR), where some endangered species experience a refuge from human disturbance. This concept is a modification of the land micro‐reserves that have been recently declared in small natural sites that keep rare plant species. A network of AMMRs would be the final objective, allowing the creation of a great metapopulation of P. ferruginea and also giving refuge to other endangered species that have been found to grow in this type of substratum. Critically, the declaration of a micro‐reserve cannot be used as a reason in favour of new construction because of the negative influence of such structures on the marine environment, together with the fact that there is no certainty that valuable species will settle on them.  相似文献   

Diatom-based reconstruction of Holocene hydrological changes along the Colorado River floodplain (northern Patagonia,Argentina)     

Rocío Fayó  Marcela A. Espinosa  Camilo A. Vélez-Agudelo  Jerónimo Pan  Federico I. Isla 《Journal of Paleolimnology》2018,60(3):427-443

Diatom assemblages recovered from a Colorado River delta core in northern Patagonia, Argentina were analyzed in order to assess past environmental conditions. A total of 35 samples were selected from a 172-cm core extracted 37 km from the mouth (39°36′19.6″S; 62°29′26.1″W). One-hundred and thirty-eight taxa were recognized and grouped according to life forms. Two diatom zones were identified by cluster analysis. At the base of the sequence, the Diatom Zone I (DZI; 4132 ± 35 ??2919?±?27 ¹⁴C yr BP), consisted of clays, and was characterized by assemblages dominated by aerophilous and benthic taxa and chrysophyte stomatocysts, which led to inferences of a sedimentary environment corresponding to a pond experiencing dry periods. The upper section (DZII) was dominated by fine sands and silts encompassing the last ~?150 yr with abundant planktonic and tychoplanktonic diatoms. Benthic diatoms were abruptly replaced by planktonic forms in this zone indicating a shift to deeper waters. These results characterize the meandering dynamics of a deltaic system. During the Mid-Holocene, more arid periods would have favored the deactivation of meanders and the formation of riverine and oxbow wetlands. In Late-Holocene and historical times, more humid conditions and the hydrological system across the floodplain reactivated the paleochannel. Today, the dominant diatom species are brackish/freshwater fragilaroids. A non-multidimensional scaling analysis showed a lack of analogy between fossil and modern samples. The change in diatom floras in recent historical times was attributed to anthropogenic disturbances, a consequence of the regulation of the river flow. This regulation is evidenced by less discharge, morphological modifications in the floodplain and increased salinity in the last decade.  相似文献