Evaluation of gene expression programming approaches for estimating daily evaporation through spatial and temporal data scanning   总被引：1，自引：0，他引：1       下载免费PDF全文

Jalal Shiri  Pau Marti  Vijay P. Singh 《水文研究》2014,28(3):1215-1225

Evaporation of water from free water surfaces or from land surfaces is one of the main components of the hydrological cycle, and its occurrence is governed by various meteorological and physical factors. There is a multitude of models developed for estimating daily evaporation values by using weather data. This paper evaluates a Gene Expression Programming (GEP) model for estimating evaporation through spatial and temporal data scanning techniques. It is by using ‘leave‐one‐out’ procedures, a complete scan of the possible train and test set configurations is carried out according to temporal and spatial criteria. Comparison of the GEP model with empirical‐physical models shows that daily evaporation values computed by the GEP model are more accurate. Further, local calibration of the GEP model may not be needed, if enough climatic data are available at other stations. The performance of the GEP model fluctuates throughout the period of study and between stations. A suitable assessment of the model should consider a complete temporal and/or spatial scan of the data set used. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Search for 248Cm in the early Solar System     

B. Lavielle  K. Marti  P. Pellas  C. Perron 《Meteoritics & planetary science》1992,27(4):382-386

Abstract— Possible evidence for the presence of ²⁴⁸Cm in the early Solar System was reported from fission gas studies (Rao and Gopalan, 1973) and recently from studies of very high nuclear track densities (≥ 5 × 10^g cm^?2) in the merrillite of the H4 chondrite Forest Vale (F. V.) (Pellas et al., 1987). We report here an analysis of the isotopic abundances of xenon in F. V. phosphates and results of track studies in phosphate/pyroxene contacts. The fission xenon isotopic signature clearly identifies ²⁴⁴Pu as the extinct progenitor. We calculate an upper limit ²⁴⁸Cm/²⁴⁴Pu < 1.5 × 10^?3 at the beginning of Xe retention in F. V. phosphates. This corresponds to an upper limit of the ratio ²⁴⁸Cm/²³⁵U ≤ 5 × 10^?5, further constraining the evidence for any late addition of freshly synthesized actinide elements just prior to Solar System formation. The fission track density observed after annealing the phosphates at 290 °C (1 hr, which essentially erases spallation recoil tracks) is also in agreement with the ²⁴⁴Pu abundance inferred from fission Xe. The spallation recoil tracks produced during the 76 Ma cosmic-ray exposure account for the very high track density in merrillites.  相似文献   

On244Pu in lunar rocks from Fra Mauro and implications regarding their origin     

K. Marti  B. D. Lightner  G. W. Lugmair 《Earth, Moon, and Planets》1973,8(1-2):241-250

The evidence forin situ produced fission xenon from²⁴⁴Pu in rock 14321 is presented. The inferred abundance ratio²⁴⁴Pu/²³⁸U is found to be consistent with values observed in a meteorite. Data from a stepwise release of the xenon permits a characterization of the trapped component, which can be shown to be distinct from solar xenon. We discuss the evidence for the presence of fission gases and of uncorrelated radiogenic argon in this and in other Apollo 14 rocks and some implications regarding their origin.Paper dedicated to Prof. Harold C. Urey on the occasion of his 80th birthday on 29 April 1973.  相似文献   

CHILEAN PORTS: COMMODITY SPECIALIZATION AND POTENTIAL FOR CONTAINERIZATION*     

Bruce E. Marti 《The Professional geographer》1985,37(3):320-328

Port commodity specialization is primarily influenced by economic functions, but also by unique geographic considerations. A port system's evolution is dependent upon a complex mix of both physical and human factors. A case study of Chilean ports examines their potential for increasing containerized traffic. By applying indices of port commodity specialization and national commodity specialization to maritime transport data, a series of working hypotheses pertinent to specialization is tested. Suggestions are made for developing a port system to accommodate containerization. The results indicate that Chile should support the development of three regional port subsystems.  相似文献   

Nitrogen in chondritic metal     

K.J. Mathew  K. Marti 《Geochimica et cosmochimica acta》2005,69(3):753-762

We report new nitrogen isotopic data in metals of H-, L- and one LL -chondrites, with N abundances in the range of ∼0.3 to 3.3 ppm and half of these <1 ppm. Nitrogen isotopic signatures in metals with low indigenous N concentrations are modified by cosmic ray spallation components; corrections are required to determine the indigenous N signatures. The metals of type 4 and 5 show uniform indigenous nitrogen (δ¹⁵N = −6.8 ± 0.5 ‰) and confirm a reported possible genetic association of chondritic metal with metal in IIE and IVA iron meteorites. Distinct isotopic signatures are observed in two metal samples of the Portales Valley (H6) meteorite which both are inconsistent with signatures in H4 and H5 chondrites, but possibly reveal a record of impact-induced melting and metamorphism on the parent asteroid. Anomalous nitrogen signatures in metals of type 3 chondrites, on the other hand, may reflect residues of surviving presolar isotopic signatures.  相似文献   

Impact of the LMDZ atmospheric grid configuration on the climate and sensitivity of the IPSL-CM5A coupled model   总被引：3，自引：3，他引：0  

Frédéric Hourdin  Marie-Alice Foujols  Francis Codron  Virginie Guemas  Jean-Louis Dufresne  Sandrine Bony  Sébastien Denvil  Lionel Guez  François Lott  Josefine Ghattas  Pascale Braconnot  Olivier Marti  Yann Meurdesoif  Laurent Bopp 《Climate Dynamics》2013,40(9-10):2167-2192

The IPSL-CM5A climate model was used to perform a large number of control, historical and climate change simulations in the frame of CMIP5. The refined horizontal and vertical grid of the atmospheric component, LMDZ, constitutes a major difference compared to the previous IPSL-CM4 version used for CMIP3. From imposed-SST (Sea Surface Temperature) and coupled numerical experiments, we systematically analyze the impact of the horizontal and vertical grid resolution on the simulated climate. The refinement of the horizontal grid results in a systematic reduction of major biases in the mean tropospheric structures and SST. The mid-latitude jets, located too close to the equator with the coarsest grids, move poleward. This robust feature, is accompanied by a drying at mid-latitudes and a reduction of cold biases in mid-latitudes relative to the equator. The model was also extended to the stratosphere by increasing the number of layers on the vertical from 19 to 39 (15 in the stratosphere) and adding relevant parameterizations. The 39-layer version captures the dominant modes of the stratospheric variability and exhibits stratospheric sudden warmings. Changing either the vertical or horizontal resolution modifies the global energy balance in imposed-SST simulations by typically several W/m² which translates in the coupled atmosphere-ocean simulations into a different global-mean SST. The sensitivity is of about 1.2 K per 1 W/m² when varying the horizontal grid. A re-tuning of model parameters was thus required to restore this energy balance in the imposed-SST simulations and reduce the biases in the simulated mean surface temperature and, to some extent, latitudinal SST variations in the coupled experiments for the modern climate. The tuning hardly compensates, however, for robust biases of the coupled model. Despite the wide range of grid configurations explored and their significant impact on the present-day climate, the climate sensitivity remains essentially unchanged.  相似文献