M5 model tree based modelling of reference evapotranspiration   总被引：1，自引：0，他引：1  

Mahesh Pal  Surinder Deswal 《水文研究》2009,23(10):1437-1443

This paper investigates the potential of M5 model tree based regression approach to model daily reference evapotranspiration using climatic data of Davis station maintained by California irrigation Management Information System (CIMIS). Four inputs including solar radiation, average air temperature, average relative humidity, and average wind speed whereas reference evapotranspiration calculated using a relation provided by the CIMIS was used as output. To compare the performance of M5 model tree in predicting the reference evapotranspiration, FAO–56 Penman–Monteith equation and calibrated Hargreaves–Samani relation was used. A comparison of results suggests that M5 model tree approach works well in comparison to both FAO–56 and calibrated Hargreaves–Samani relations. To judge the generalization capability of M5 model tree approach, model created by using the Davis data set was tested with the datasets of four different sites. Results from this part of the study suggest that M5 model tree could successfully be employed in modeling the reference evapotranspiration. Further, sensitivity analysis with M5 model tree approach suggests the suitability of solar radiation, average air temperature, average relative humidity, and average wind speed as input parameters to model the reference evapotranspiration Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Analysis of magnetovariational response functions     

M. N. Berdichevsky  V. A. Kuznetsov  N. A. Pal’shin 《Izvestiya Physics of the Solid Earth》2009,45(3):179-198

Advances in magnetovariational sounding are stimulating further development of this area of deep geoelectrics. The paper contains a review of magnetovariational response functions revealing their main properties and proposing new methods of their analysis. The theory of magnetic perturbation ellipses having a higher resolution is set forth and methods of the decomposition of magnetovariational functions are discussed that allow one to reduce 3D magnetovariational interpretation to two or three independent 2D inversions and eliminate the effect of 2D regional structures of the geoelectric background.  相似文献   

The Gyldén‐type problem revisited: More refined analytical solutions     

A. Pal  D. elaru  V. Mioc  C. Cucu‐Dumitrescu 《Astronomische Nachrichten》2006,327(4):304-308

We resume and consistently extend our previous researches concerning the Gyldén‐type problem (a two‐body problem with time‐dependent equivalent gravitational parameter). To approach most of the concrete astronomical situations to be modelled in this way, we consider a periodic small perturbation. For the nonresonant case, we present a second‐order analytical solution. For the resonant case, we adopt the most realistic astronomical situation: only one dominant term of the Hamiltonian. In this case we point out a fundamental model of resonance, common to every resonant situation, and, moreover, identical to the first fundamental model of resonance . Considering the simplest model of periodic change of the equivalent gravitational parameter, we .nd that all possible resonances are con.ned to the first fundamental model. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Landslide risk analysis between Giri and Tons Rivers in Himachal Himalaya (India)     

Piyoosh Rautela  Ramesh Chandra Lakhera 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)

The area around Sataun in the Sirmur district of Himachal Pradesh, India (falling between the rivers Giri and Tons; both tributaries of the Yamuna River) was studied for landslide vulnerability on behalf of the inhabitants. The study was made using extensive remote sensing data (satellite and airborne). It is well supported by field evidence, demographic and infrastructural details and aided by Geographic Information System (GIS) based techniques. Field observations testify that slope, aspect, geology, tectonic planes, drainage, and land use all influence landslides in the region. These parameters were taken into consideration using the statistical approach of landslide hazard zonation. Using the census data of 1991, vulnerability of the populace to the landslide hazard was accessed. As most of the infrastructure in the region is concentrated around population centres, population data alone was used for vulnerability studies.  相似文献   

An ultrasoft X-ray source (RX 215319−1514) and discovery of a narrow‐line Seyfert 1 galaxy     

Kulinder Pal Singh  Laurence R. Jones 《Monthly notices of the Royal Astronomical Society》2000,312(2):380-386

We present results on the identification of the optical counterpart of an ultrasoft X-ray source discovered with ROSAT . Two optical candidates – a galaxy and a star – are found within the error circle of the X-ray source position. Optical spectroscopy of the two candidates reveals that (a) the galaxy is a narrow-line Seyfert type 1 galaxy, and (b) the star is a late A-type or an early F-type. The F _x F _v ratio is too high for the star to be the counterpart of the X-ray source, but consistent with that for an active galaxy. Although higher-resolution X-ray imaging of the region is needed to definitely settle the question of the counterpart of the X-ray source, the narrow-line Seyfert 1 galaxy is the best candidate. The spectral properties of the newly discovered narrow-line Seyfert 1 galaxy are also presented, including its extreme X-ray power-law spectral index of Γ≥4.  相似文献   

Comments on the heating of solar active regions by magnetic energy dissipation     

Suresh Chandra 《Astrophysics and Space Science》1986,123(2):403-404

The method of Kumar and Narain (1985) to calculate the twisting velocity of magnetic field appears to be erroneous. Hence, their conclusion about Tucker's proposal for the heating of active regions by magnetic energy dissipation may not be correct.  相似文献   

Trapezoidal footings on non-linear subgrades     

S. Chandra  M. R. Madhav  N. G. R. Iyengar 《国际地质力学数值与分析法杂志》1984,8(6):519-529

The pressure versus settlement response is highly non-linear for soils, in general. In the present study, a cubic equation of the type p = K₁w ? K₂w³ is suggested to incorporate the non-linear behaviour. A trapezoidal footing with constant depth resting on a subgrade having non-linear response is analysed. The resulting fourth order non-linear differential equation with variable coefficients is solved by using the Galerkin technique and beam characteristic functions are employed to obtain faster convergence. The results are presented in the form of non-dimensional charts for valid ranges of footings and soil parameters.  相似文献   

Solar coronal loop     

Suresh Chandra 《Astrophysics and Space Science》1985,113(1):193-194

The conclusions drawn by Narain (1983) appear to be in error.  相似文献   

SS 433: results of a recent multiwavelength campaign     

Sandip K. Chakrabarti  B. G. Anandarao  S. Pal  Soumen Mondal  A. Nandi  A. Bhattacharyya  Samir Mandal  Ram Sagar  J. C. Pandey  A. Pati  S. K. Saha 《Monthly notices of the Royal Astronomical Society》2005,362(3):957-965

  相似文献   

In memoriam     

Chandra S. Desai 《国际地质力学数值与分析法杂志》1992,16(1):1-2

  相似文献