Calculation of the structural properties of asymmetrical nuclear matter     

Gholam Hossein Bordbar  Hamideh Nadgaran 《天体物理学报》2012,(3):345-358

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Physical origin of multi-wavelength emission of GRB 100418A and implications for its progenitor     

Lan-Wei Jia  Xue-Feng Wu  Hou-Jun Lti  Shu-Jin Hou  En-Wei Liang 《天体物理学报》2012,(4):411-418

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The new RS CVn binary V1034 Her revisited and the orbital period—activity relation of short-period RS CVn binaries using photometric distortion amplitude     

Li-Yun Zhang 《天体物理学报》2012,(4):433-442

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Analyse statistique des séquences sèches dans un bassin du nord de la Tunisie / Statistical analysis of dry events in a northern Tunisian basin     

《水文科学杂志》2013,58(3):442-455

Abstract

A comparative statistical study of dry events during the rainy season is presented. In particular, we carried out statistical processing of the daily records of raingauges in the downstream basin of Lake Ichkeul, in the north of Tunisia. The climate is characterized by a rainy season lasting from the autumn until spring. The Poisson distribution was applied to describe the number of rainfall events, and negative binomial distribution was applied for the length of the dry events, in the rainy season. Since rainfall events are shorter, their duration follows a geometrical distribution, as theoretically required. For planning purposes, the longest seasonal dry spells associated with the various statistical recurrence periods are derived on the basis of the fitted GEV functions. A hydrological year starts at the beginning of the first rainfall event of a given season. The length of hydrological year is determined by the time interval between the start dates of two subsequent rainy seasons. The beginning of the hydrological year occurs on average toward mid-September, but the probability of it occurring before 15 September exceeds 40%. Spatial analysis of dry events is also done. A significant fraction of the dry events occurred for at least two stations simultaneously. Furthermore, 4.5% of the dry events have been observed at all three stations. The analysis of the dry events gives an alternative method to examine the dry spell phenomenon.  相似文献   

PUBLICATIONS OF THE IAHS     

《水文科学杂志》2013,58(3):365-370

Abstract

Gauging stations where the stage—discharge relationship is affected by hysteresis due to unsteady flow represent a challenge in hydrometry. In such situations, the standard hydrometric practice of fitting a single-valued rating curve to the available stage—discharge measurements is inappropriate. As a solution to this problem, this study provides a method based on the Jones formula and nonlinear regression, which requires no further data beyond the available stage—discharge measurements, given that either the stages before and after each measurement are known along with the duration of each measurement, or a stage hydrograph is available. The regression model based on the Jones formula rating curve is developed by applying the monoclinal rising wave approximation and the generalized friction law for uniform flow, along with simplifying assumptions about the hydraulic and geometric properties of the river channel in conjunction with the gauging station. Methods for obtaining the nonlinear least-squares rating-curve estimates, while factoring in approximated uncertainty, are discussed. The broad practical applicability and appropriateness of the method are demonstrated by applying the model to: (a) an accurate, comprehensive and detailed database from a hydropower-generated highly dynamic flow in the Chattahoochee River, Georgia, USA; and (b) data from gauging stations in two large rivers in the USA affected by hysteresis. It is also shown that the model is especially suitable for post-modelling hydraulic and statistical validation and assessment.  相似文献   

A METHOD OF ESTIMATING THE PROBABILITY OF OCCURRENCE OF SNOW WATER EQUIVALENTS IN THE UNITED KINGDOM / Méthode pour l'évaluation de la probabilité de l'occurrence des équivalents neige-eau au Royaume Uni     

MERVYN C. JACKSON 《水文科学杂志》2013,58(1):127-142

Abstract

A simple guide (shown in the appendix) is produced, which enables a water manager or engineer to make an estimate of statistics of water equivalent of snow cover for return periods between 5 and 100 years for most places in the United Kingdom. This paper describes how the guide was produced using many different sources of data. The methods described here will be of help to both meteorologists and hydrologists in temperate countries with similar snow questions.  相似文献   

Data time-step dependency of conceptual rainfall—streamflow model parameters: an empirical study with implications for regionalisation     

《水文科学杂志》2013,58(4):685-695

Abstract

Employing 1-, 2-, 4-, 6-, 12- and 24-hourly data sets for two catchments (10.6 and 298 km²) in Wales, the calibrated parameters of a unit hydrograph-based model are shown to change substantially over that range of data time steps. For the smaller basin, each model parameter reaches, or approaches, a stable value as the data time step decreases, providing a straightforward method of estimating time-step independent model parameter values. For the larger basin, the model parameters also reach, or approach, stable values using hourly data, but, for reasons given in the paper, interpretation of the results is more difficult. Model parameter sensitivity analyses are presented that give insights into the relative precision on the parameters for both catchments. The paper discusses the importance of accounting for model parameter data time-step dependency in pursuit of a reduction in the uncertainty associated with estimates of flow in ungauged basins, and suggests that further work along these lines be undertaken using different catchments and models.  相似文献   

On width function-based unit hydrographs deduced from separately random self-similar river networks and rainfall variability: Discussion of “Coding random self-similar river networks and calculating geometric distances: 1. General methodology” and “2. Application to runoff simulations”     

《水文科学杂志》2013,58(1):230-237

Abstract

Hung & Wang (2005a,b) base their approach on successive steps related to a kind of geomorphometric modelling, the deduction of a rainfall—runoff transfer function, and the application to a Taiwanese basin subject to typhoons. Several conceptual points of each of these steps and their propagation through the whole approach are discussed; referring to the likelihood of the proposed separately random self-similar river networks, the deduction of width function-based unit hydrographs, and the accounting for variability of rainfall and of induced runoff.  相似文献   

Infiltration in the Corgo River basin (northern Portugal): coupling water balances with rainfall—runoff regressions on a monthly basis     

《水文科学杂志》2013,58(6):989-1005

Abstract

A combination of water balances and rainfall—runoff regressions is used to calculate infiltration, overland flow, baseflow and change to the surface water reservoir, on a monthly basis; evapotranspiration from the underground reservoir, on an annual basis; and a lag phase of maximum infiltration and maximum baseflow within a hydrological year. The water balance equations are written for catchment areas formed on crystalline rocks and located in temperate climates. The regression lines are fitted to precipitations and river flows. In a first run, the model is tested with the Corgo River hydrographic basin, a small watershed in the Trás-os-Montes and Alto Douro province, northern Portugal. The results compare favourably with results of other groups, working under similar environmental conditions. The sensitivity of the model to changes in the basin characteristics and climate is tested by a second run using data from the Terva River basin, a nearby catchment that is much smaller than the Corgo basin and has a much lower effective precipitation, defined here as a difference between precipitation and potential evapotranspiration. As a consequence of having a lower effective precipitation, the river dry-out starts earlier in the Terva (May) than in the Corgo (June).  相似文献   

Remarks upon numerical solutions of infiltration into a soil profile     

《水文科学杂志》2013,58(2):349-362

Abstract

A methodology of time-step estimation for numerically solving the Richards equation is discussed. Its importance in simulating water movement in unsaturated—saturated soils is shown for infiltration into a soil profile by applying various time-step estimations and boundary conditions for different soils. In order to test the results of the computations, infiltration theory was applied. According to infiltration theory, the pressure head in the initially unsaturated part will not take positive values as long as the moisture front has not reached the phreatic level, or, in the case of a profile with a free-draining lower boundary, it is not saturated at the base. In other cases, the appearance of positive values of the pressure head produces incorrect values for the inflow rate q.  相似文献