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101.
Modeling monthly mean air temperature for Brazil 总被引:1,自引:1,他引:0
Clayton Alcarde Alvares José Luiz Stape Paulo Cesar Sentelhas José Leonardo de Moraes Gonçalves 《Theoretical and Applied Climatology》2013,113(3-4):407-427
Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant (α?≤?0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67?×?108?pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories. 相似文献
102.
Pedro S.B.REYES Mauricio E.VALAREZO Jenry CóRDOVA Fran?ois A.MICHAUD Camilo ZAPATA 《山地科学学报》2018,15(5):966-975
The longitudinal profile of a river channel can be described in function of mathematical expressions. The logarithmic fit is the most used method to describe the relative equilibrium of a channel elevation profile. Rivers showing zones of high channel gradient and convex-upward profiles can be evaluated in function of the offset distance with respect to the logarithmic curve. The Jama River profile has been constructed using differential GPS data for the downstream reach and 4-m-grid DEM data base for the remaining headward profile. The resulting longitudinal profile shows a prominent knickpoint of about 80 m in elevation characterized by sharp local convexity. The offset distance in vertical direction from the logarithmic plot is interpreted as the successive accumulation of multiple uplift episodes associated with the Jama Fault System activity. The horizontal offset is suggested to represent the remaining retreated distance for the upstream propagation of the Jama knickpoint. The highly resistant Cretaceous rocks outcropping along the Jama knickpoint reach acts as an inflection point between two subprofiles that show well-fitted logarithmic curves, thereby representing a temporary partitioned equilibrium along the Jama River profile. 相似文献
103.
Yannick Giraud-Héraud Jean Kaplan François De Volnay Martin Charling Tao Sylvaine Turck-Chièze 《Solar physics》1990,128(1):21-33
The Saclay solar evolution code is used to check the effect of WIMPs on solar evolution. In this paper we study the effects of various types of Cosmion-matter interactions, give constraints on the crosssections compatible with the measured neutrino rate of 2 SNU on chlorine, and relate these constraints to ongoing dark matter detection experiments.Unité associée au CNRS UA 280, F-75251 Paris Cedex 05, France.On leave from LPC, Collège de France. 相似文献
104.
按溃变理论[1]的不连续或非均匀信息不仅可以预测天气系统的移动性变化和转折性变化,也可以预测降水等天气现象。并已被多次历史例案和应用实践所验证。为了便于投入业务运用,我们利用数据库系统,实现了体现资料信息非均匀和不连续的广义参数在微机、填图机上的自动化处理,完成了收报、计算和填图分析的自动化。本方法体现了预报工具的改革也充分地利用了现有的资料资源 相似文献
105.
A comment is made on the Edmonds' study of the low-wavenumber power of solar granulation. It is concluded that its one-dimensional power spectrum is biased, and that the corresponding two-dimensional power spectrum shows negative parts. 相似文献
106.
T. Ataç 《Astrophysics and Space Science》1989,159(1):173-176
In this Letter we obtained the fluctuation curves from the differences of unsmoothed and smoothed values of the different solar activity indices. We compared the pattern of fluctuations of these curves. Also using monthly mean values of each index we studied the degree of correlation between the pairs of indices during the selected time intervals. 相似文献
107.
Seismic bearing capacity of shallow strip footings 总被引:6,自引:0,他引:6
Deepankar?ChoudhuryEmail author Kanakapura?S.?Subba Rao 《Geotechnical and Geological Engineering》2005,23(4):403-418
Seismic bearing capacity of shallow strip footings in soil has been obtained in the form of pseudo-static seismic bearing capacity factors Ncd, Nqd and Nd, denoting the cohesion, surcharge and unit weight components, respectively, by an extensive numerical iteration technique. Limit equilibrium method of analysis with composite failure surface is assumed. The validity of the principle of superposition is examined. Effects of both the horizontal and vertical seismic acceleration coefficients have been found to always reduce the ultimate bearing capacity significantly. Results obtained by the present method of analysis are compared with the available results and are found to be the least in the seismic case. 相似文献
108.
Optimum design of nailed soil slopes 总被引:12,自引:0,他引:12
In this paper, a generalized method of computer based optimum design of soil-nailed slopes is reported. A limit equilibrium formulation satisfying overall and internal equilibrium and considering the effect of tensile resistance of the reinforcement has been used in computing the stability of nailed slopes. The quantity of steel requirement for raising the factor of safety to a desired value is estimated. The location, size (length and diameter) and orientation of the nails and the location and shape of the critical shear surface have been treated as variables. The solutions have been isolated by formulating the problem as one of non-linear programming. The applicability of the developed method has been verified by comparing the predicted failure surfaces with those observed in model tests as well as in the field and also reported theoretical results. 相似文献
109.
Field equations are obtained with the aid of higher dimensional Bianchi type-I cosmological model in scale covariant theory
of gravitation in the context of cosmic strings. We present here isotropic and anisotropic solutions of the field equations
and some physical implications of these solutions are briefly discussed. 相似文献
110.
K.?S.?AdhavEmail author S.?D.?Katore S.?V.?Thakare 《Astrophysics and Space Science》2005,299(3):233-238
A problem of static plane symmetric metric in the perfect fluid, the mesonic massive scalar field and in their coupling is
studied in Rosen’s (1973) bimetric theory of relativity. It was found that the matter field like either perfect fluid or mesonic
massive scalar field or their coupling does not survive in bimetric theory of gravitation when the space–time is governed
by n-dimensional static plane symmetric metric. 相似文献