Identifying advantages and drawbacks of two hydrological models based on a sensitivity analysis: a study in two Chilean watersheds     

Víctor Parra  Patricio Fuentes-Aguilera 《水文科学杂志》2013,58(12):1831-1843

ABSTRACT

Hydrological modelling has undergone constant growth with the increase in information processing capabilities. Hydrological models have traditionally been used to study the effects of climate change on management and land-use changes and for water resources planning, among other purposes. The aim of this study was to determine and analyse the advantages of the HBV and HYMOD models, which are commonly used in hydrology on daily and monthly time scales. A regional sensitivity analysis was used to compare the processes that take on greater importance at different time scales in the two models. As a result, it was found that quick precipitation–runoff processes prove to be better represented in the HBV model, while slow, time-aggregated processes are better represented by the HYMOD model. This study confirms that both models are adequate for rain-dominated basins, such as those of the study area. Additionally, the HBV model proved to be more robust in comparison to HYMOD.  相似文献   

A Thin Ring Model for the Oh Megamaser in Iiizw35     

Rodrigo Parra  John Conway  Moshe Elitzur 《Astrophysics and Space Science》2005,295(1-2):325-330

We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phase of unsaturated clumpy gas distributed in a thin ring structure and amplifying background continuum. We emphasize the importance of clumpiness in the OH masing medium, an effect that has not been fully appreciated previously.The model explains why multiple bright spots are seen only at the ring tangents while smoother emission is found elsewhere. Both the observed velocity gradients and the line to continuum ratios around the ring enquire a geometry where most of the seed photons come from a continuum emission which lies outside the OH ring. To explain both the OH and continuum brightness, free-free absorbing gas is required along the ring axis to partially absorb the far side of the ring. It is proposed that the required geometry arises from an inwardly propagating ring of starburst activity.  相似文献   

Local Habitat Influences on Feeding and Respiration of the Intertidal Mussels <Emphasis Type="Italic">Perumytilus purpuratus</Emphasis> Exposed to Increased <Emphasis Type="Italic">p</Emphasis>CO<Subscript>2</Subscript> Levels     

Luisa M. Saavedra  Diego Parra  Valeska San Martin  Nelson A. Lagos  Cristian A. Vargas 《Estuaries and Coasts》2018,41(4):1118-1129

Coastal ecosystems are exposed to changes in physical-chemical properties, such as those occurring in upwelling and freshwater-influenced areas. In these areas, inorganic carbon can influence seawater properties that may affect organisms and populations inhabiting benthic habitats such as the intertidal mussel Perumytilus purpuratus. Feeding and metabolic responses were measured in adult mussels from two geographic regions (central and southern Chile) and two local habitats (river-influenced and non-river-influenced) and three pCO₂ levels (380, 750, and 1200 μatm pCO₂ in seawater). The feeding rates of mussels tend to increase at high pCO₂ levels in seawater; however this response was variable across regions and local habitats. In contrast, there was no difference in the respiratory rate of mussels between geographic areas, but there was a significant reduction of oxygen consumption at intermediate and high levels of pCO_2. The results indicate that river-influenced organisms compensate for reductions in metabolic cost at elevated pCO₂ levels by having their energy demands met, in contrast with non-river-influenced organisms. The lack of regional-scale variability in the physiological performance of mussels may indicate physiological homogeneity across populations and thus potential for local adaptation. However, the local-scale influences of river- and non-river-influenced habitats may counterbalance this regional response promoting intra-population variability and phenotypic plasticity in P. purpuratus. The plasticity may be an important mechanism that allows mussels to confront the challenges of projected ocean acidification scenarios.  相似文献   

Zur Struktur der Phasengrenze Metallo xid/Elektrolyt-Potentialbildung und Ladungsbilanz     

V. Ender 《洁净——土壤、空气、水》1991,19(2):199-208

Details of the formation of potentials at a metal-oxide/H₂O interphase are described. On the one hand the whole potential drop consists of one fixed (HELMHOLTZ layer) and two diffuse parts (space charge in the oxide phase and GOUY layer in the electrolyte), on the other hand it is given as sum of free charges and dipols. Besides the PZC the charge distribution is determined above all by the pH value of the electrolyte under conditions without an external current. The following cases can be qualitatively distinguished in connection with the important pH_22°c =7.  相似文献   

Limnological studies of Amarga Lagoon,Chile: A saline lake in Patagonian South America     

Hugo Campos  Doris Soto  Oscar Parra  Wladimir Steffen  Gloria Aguero 《International Journal of Salt Lake Research》1995,4(4):301-314

Amarga Lagoon, lat. 50°29 S and long. 73°45 S, it is located at the Torres del Paine National Park, Chile. The physical, chemical, and biological features of the lake were studied. According to salinity, the lake is mesosaline. Sodium and chloride were the dominant ions. Nitrogen was potentially limiting for phytoplankton growth. One Cyanophyceae species andArtemia were the predominant species in the plankton.Artemia provided abundant food for flamingoes.  相似文献   

Zur indirekten Ermittlung von Selektivitätskoeffizienten für Ionenaustauschreaktionen     

V. Ender  J. Bosholm 《洁净——土壤、空气、水》1985,13(4):413-419

A relation is derived for the calculation of unknown selectivity coefficients from unknown values of tertiary reactions and its validity is proved by experimental investigations of the systems H⁺/Na⁺/Ca²⁺, H⁺/Na⁺/Co²⁺ and H⁺/Na⁺/Al³⁺ at the strongly acid cation exchanger Wofatit KPS.  相似文献   

Hemolytic activity and fatty acids composition in the ichthyotoxic dinoflagellate Cochlodinium polykrikoides isolated from Bahía de La Paz, Gulf of California     

Juan Jos Dorantes-Aranda  Luz María García-de la Parra  Rosalba Alonso-Rodríguez  Lourdes Morquecho 《Marine pollution bulletin》2009,58(9):1401-1405

The hemolytic activity of the dinoflagellate Cochlodinium polykrikoides from Bahía de La Paz, Gulf of California was investigated as part of the ichthyotoxic mechanism of this microalga. Two different kinds of erythrocytes, fish and human, were tested for the hemolytic assay. Since fatty acids have been associated with hemolytic activity in C. polykrikoides, the composition of fatty acids of this dinoflagellate was also analyzed. The concentration of C. polykrikoides causing 50% hemolysis (HE₅₀) was 4.88 and 5.27 × 10⁶ cells L⁻¹, for fish and human erythrocytes, respectively. According to the standard curve of saponin, an equivalence between the hemolytic activity of saponin and the dinoflagellate concentration was found with 1 μg saponin mL⁻¹ equivalent to 1 × 10⁶ cells L⁻¹ of C. polykrikoides. The polyunsaturated fatty acids: hexadecaenoic (16:0), docosahexaenoic (22:6 n3) and octadecapentaenoic (18:5 n3) were found in an abundance of 62% of total fatty acids.  相似文献   

Tectonic controls on Cenozoic foreland basin development in the north‐eastern Andes,Colombia     

Mauricio Parra  Andrés Mora  Carlos Jaramillo  Vladimir Torres  Gerold Zeilinger  Manfred R. Strecker 《Basin Research》2010,22(6):874-903

In order to evaluate the relationship between thrust loading and sedimentary facies evolution, we analyse the progradation of fluvial coarse‐grained deposits in the retroarc foreland basin system of the northern Andes of Colombia. We compare the observed sedimentary facies distribution with the calculated one‐dimensional (1D) Eocene to Quaternary sediment‐accumulation rates in the Medina wedge‐top basin and with a three‐dimensional (3D) sedimentary budget based on the interpretation of ～1800 km of industry‐style seismic reflection profiles and borehole data. Age constraints are derived from a new chronostratigraphic framework based on extensive fossil palynological assemblages. The sedimentological data from the Medina Basin reveal rapid accumulation of fluvial and lacustrine sediments at rates of up to ～500 m my^?1 during the Miocene. Provenance data based on gravel petrography and paleocurrents reveal that these Miocene fluvial systems were sourced from Upper Cretaceous and Paleocene sedimentary units exposed to the west in the Eastern Cordillera. Peak sediment‐accumulation rates in the upper Carbonera Formation and the Guayabo Group occur during episodes of coarse‐grained facies progradation in the early and late Miocene proximal foredeep. We interpret this positive correlation between sediment accumulation and gravel deposition as the direct consequence of thrust activity along the Servitá–Lengupá faults. This contrasts with one class of models relating gravel progradation in more distal portions of foreland basin systems to episodes of tectonic quiescence.  相似文献   

Significance and petrochemistry of upper mantle–mantle transition zone metaperidotites and oceanic crust metagabbros within the Kazdağı metaophiolite: implications for the geological evolution of the Izmir–Ankara–Erzincan Ocean, northwestern Turkey     

Ender SARIFAKIOGLU  Mustafa SEVIN  Yildirim DILEK  Andreas M?LLER 《《地质学报》英文版》2018,92(Z2):6-6

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