Interpolation de variables régionales et cartographie automatique: modèle triangulaire hydrologique (MTH) / Interpolation of regional variables and automatic drawing of isoplets     

HIZIR ÖNSOY  C. BOCQUILLON 《水文科学杂志》2013,58(3):297-306

Abstract

The degree of relationship between hydrological variables being independent of time series properties is especially related to the distance between gauging stations of these variables. The linear character of these variables without extreme deviation in time makes possible the use of a new method of interpolation. Following is an explanation of a method which generalizes methods of linear interpolation of two points. Computing the variable values at each point, automatic drawing of isoplets and the water height in a basin can be easily computed by this method.  相似文献   

Spillway design floods in Sweden: I. New guidelines     

STEN BERGSTRÖM  JOAKIM HARLIN  GÖRAN LINDSTRÖM 《水文科学杂志》2013,58(5):505-519

Abstract

The new Swedish guidelines for the estimation of design floods for dams and spillways are presented, with emphasis on high-hazard dams. The method is based on a set of regional design precipitation sequences, rescaled for basin area, season and elevation above sea level, and a full hydrological model. A reservoir operation strategy is also a fundamental component of the guidelines. The most critical combination of flood generating factors is searched by systematically inserting the design precipitation sequence into a ten year climatological record, where the initial snowpack has been replaced by a statistical 30-year snowpack. The new guidelines are applicable to single reservoir systems as well as more complex hydroelectric schemes, and cover snowmelt floods, rain floods and combinations of the two. In order to study the probabilities of the computed floods and to avoid regional inconsistencies, extensive comparisons with observed floods and frequency analyses have been carried out.  相似文献   

Effect of Aftershocks on Earthquake Hazard Estimation: An Example from the North Anatolian Fault Zone   总被引：2，自引：0，他引：2  

Öncel  A. O.  Alptekin  Ö. 《Natural Hazards》1999,19(1):1-11

In order to investigate the effect of aftershocks on earthquake hazard estimation, earthquake hazard parameters (_m, b and M_max) have been estimated by the maximum likelihood method from the main shocks catalogue and the raw earthquakes catalogue for the North Anatolian Fault Zone (NAFZ). The main shocks catalogue has been compiled from the raw earthquake catalogue by eliminating the aftershocks using the window method. The raw earthquake catalogue consisted of instrumentally detected earthquakes between 1900 and 1992, and historical earthquakes that occurred between 1000–1900. For the events of the mainshock catalogue the Poisson process is valid and for the raw earthquake catalogue it does not fit. The paper demonstrates differences in the hazard outputs if on one hand the main catalogues and on the other hand the raw catalogue is used. The maximum likelihood method which allows the use of the mixed earthquake catalogue containing incomplete (historical) and complete (instrumental) earthquake data is used to determine the earthquake hazard parameters. The maximum regional magnitude (M_max, the seismic activity rate (_m), the mean return period (R) and the b value of the magnitude-frequency relation have been estimated for the 24°–31° E, 31°–41° E, 41°–45° E sections of the North Anatolian Fault Zone from the raw earthquake catalogue and the main shocks catalogue. Our results indicate that inclusion of aftershocks changes the b value and the seismic activity rate _m depending on the proportion of aftershocks in a region while it does not significantly effect the value of the maximum regional magnitude since it is related to the maximum observed magnitude. These changes in the earthquake hazard parameters caused the return periods to be over- and underestimated for smaller and larger events, respectively.  相似文献   

North-south asymmetries in the green corona brightness between 1947 and 1976     

Özgüç  Atila  Üçer  Cumhure 《Solar physics》1988,114(1):141-146

The north-south asymmetry has been studied using the green emission corona brightness in the period of 1947–1976. (N - S)/(N + S) values are constructed with the 5-deg opposite coronal belts brightnesses between ± 5 and ± 60 deg. Power spectra analyses were performed to study periodicities of these (N - S)/(N + S) values. Two noticeable periodicities (14.5 and 5 yr) have been found.  相似文献   

On some flare-sensitive high photospheric and low chromospheric lines     

Yngve Öhman 《Solar physics》1969,10(1):178-183

During a stay at the Kitt Peak National Observatory the writer has tried to find an influence of flare radiation on the high photospheric and low chromospheric lines of the area occupied by the flare. Observations have been made in the H region and in the region of the H and K lines. When flare emission is present in sunspots some of the faint (molecular) lines seem to be weakened. When a flare appears near the solar limb some of the Evershed-type (chromospheric) lines are strongly influenced.Kitt Peak National Observatory Contribution No. 481.Visiting Astronomer to the Solar Division, Kitt Peak National Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation.  相似文献   

GUP assisted Hawking radiation of rotating acoustic black holes     

I. Sakalli  A. Övgün  K. Jusufi 《Astrophysics and Space Science》2016,361(10):330

  相似文献   

High latitude helical surge of May 22, 1989     

Adnan Ökten  Hikmet Çakmak 《Solar physics》1990,128(2):365-369

A helical surge (S 72, W 90) was recorded by a monochromatic filter at the University Observatory of Istanbul. It is a significient one at a very high latitude and without any center of activity. A sequence of the filtergrams showed some condensed points from which the motions of the plasma are traced. Different velocities were determined on each of the branches of the helical surge during its evolution. The surge reached its maximum height of 298 000 km and the maximum velocity of this upper region was 250 km s^–1.  相似文献   

Temporal Offsets Between Maximum CME Speed Index and Solar,Geomagnetic, and Interplanetary Indicators During Solar Cycle 23 and the Ascending Phase of Cycle 24     

A. Özgüç  A. Kilcik  K. Georgieva  B. Kirov 《Solar physics》2016,291(5):1533-1546

  相似文献   

Bounce Rock—A shergottite‐like basalt encountered at Meridiani Planum,Mars     

Jutta ZIPFEL  Bradley L. JOLLIFF  Ralf GELLERT  Kenneth E. HERKENHOFF  Rudolf RIEDER  Robert ANDERSON  James F. BELL III  Johannes BRÜCKNER  Joy A. CRISP  Philip R. CHRISTENSEN  Benton C. CLARK  Paulo A. De SOUZA Jr.  Gerlind DREIBUS  Claude D’USTON  Thanasis ECONOMOU  Steven P. GOREVAN  Brian C. HAHN  Göstar KLINGELHÖFER  Timothy J. McCOY  Harry Y. McSWEEN Jr.  Douglas W. MING  Richard V. MORRIS  Daniel S. RODIONOV  Steven W. SQUYRES  Heinrich WÄNKE  Shawn P. WRIGHT  Michael B. WYATT  Albert S. YEN 《Meteoritics & planetary science》2011,46(1):1-20

Abstract– The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic shergottites. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene‐rich mineralogy, which is also evident in Mössbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X‐ray spectrometer. The correspondence of Bounce Rock’s chemical composition with the composition of certain basaltic shergottites, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe/Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3 km in diameter, located 75 km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic shergottite meteorites from Mars.  相似文献   

Absolute parameters of the newly-identified contact binary star IS Canis Major     

B. Özkardeş  A. Erdem 《New Astronomy》2010,15(2):247-253

This paper presents the results of the first high-resolution spectroscopic observations of the Southern W UMa type system IS CMa. Spectroscopic observations of the system were made at Mt. John University Observatory using a HERCULES fibre-fed échelle spectrograph in September 2007. The first radial velocities of the component stars of the system were determined by using the spectral disentangling technique. The resulting orbital elements of IS CMa are: $a_1\sin i=0.0041\pm 0.0001$ AU, $a_2\sin i=0.0135\pm 0.0001$ AU, $M_1{\sin }^{3}i=1.48\pm 0.01{\mathrm{M}}_{\odot }$, and $M_2{\sin }^{3}i=0.44\pm 0.01{\mathrm{M}}_{\odot }$. The components were found to be in synchronous rotation taking into account the disentangled ${\mathrm{H}}_{\delta }$ line profiles of both components of the system. The Hipparcos light curve was solved by means of the Wilson–Devinney method supplemented with a Monte Carlo type algorithm. The radial velocity curve solutions including the proximity effects give the mass ratio of the system as 0.297 ± 0.001. The combination of the Hipparcos light and radial velocity curve solutions give the following absolute parameters of the components: $M_1=1.68\pm 0.04{\mathrm{M}}_{\odot }\text{,}{\mathrm{M}}_2=0.50\pm 0.02{\mathrm{M}}_{\odot }\text{,}{R}_1=2.00\pm 0.02{\mathrm{R}}_{\odot }\text{,}{R}_2=1.18\pm 0.03R_{\odot }\text{,}{L}_1=7.65\pm 0.60$ ${\mathrm{L}}_{\odot }$ and $L_2=1.99\pm 0.80{\mathrm{L}}_{\odot }$. The distance to IS CMa was calculated as $87\pm 5$ pc using the distance modulus with corrections for interstellar extinction. The position of the components of IS CMa in the HR diagram are also discussed: the system seems to have an age of 1.6 Gyr.  相似文献