基于客观分析的多源卫星叶绿素a浓度产品融合方法研究          下载免费PDF全文

施英妮  张亭禄  石立坚  胡晓华  南明星 《海洋学报》2016,38(3):82-87

本文基于Aqua/MODIS、Terra/MODIS和Envisat/MERIS多源卫星叶绿素a浓度产品,研究了客观分析融合方法,制作了西北太平洋海域(0°~50°N,100°~150°E)叶绿素a浓度融合产品,并从有效数据空间覆盖率和产品精度两个方面对融合方法进行了评价。与单传感器以及欧洲太空局发布的GSM模型业务化融合产品相比,客观分析融合产品空间覆盖率明显提高;与收集的2002-2012年间叶绿素a浓度实测数据比较,GSM模型业务化融合产品的匹配数据点为578个,偏差为-0.20 mg/m3,均方根误差为0.37 mg/m3,客观分析法融合产品的匹配数据点为1432个,偏差为-0.21 mg/m3,均方根误差为0.36 mg/m3。结果表明:本文研究的客观分析融合方法在保证融合产品精度的同时可显著提高产品的空间覆盖率,在海洋水色融合应用前景广阔。  相似文献   

Age and growth of Cape stumpnose Rhabdosargus holubi (Pisces: Sparidae) in the Eastern Cape,South Africa     

MW Farthing  NC James  WM Potts 《African Journal of Marine Science》2016,38(1):65-71

Rhabdosargus holubi is a small (maximum weight=2.4?kg) yet important fishery species in the estuaries of the south-east coast of South Africa. Little is known of its biology and specifically its growth rate, which is essential for sustainable management of the fishery. We examined and counted the opaque zones in the sectioned otoliths of 134 R. holubi to determine its age and growth parameters. The otoliths from two recaptured fish marked with oxytetracycline confirmed that one opaque zone was deposited annually. The species reached a maximum age of 18 years and growth was adequately described by a von Bertalanffy growth function of the form: L_t = 358.1 (1 – e^{?0.24(t+0.77)}) mm fork length. There were no significant differences between any of the male and female growth parameters (likelihood ratio test: p = 0.3). The growth was slow (omega index: ω = 86.56); however, despite this, the unique life history of R. holubi may provide a degree of resilience to heavy fishing pressure in estuaries.  相似文献   

PRINCIPAL COMPONENTS REGRESSION FOR ROUTINE MULTICOMPONENT UV DETERMINATIONS: A VALIDATION PROTOCOL     

PAULJ.GEMPERLINE  ALGER SALT 《地理学报(英文版)》1989,(1)

A validation protocol for multicomponent spectroscopic assays based on principal componentsregression is described. Factorial design and hypothesis tests are used to establish the linearity andabsence of interaction between components in the regression model. Testing considers multiple responsevariables simultaneously so that correlation between residuals is properly treated. Assay reproducibilityand sensitivity to related substances are evaluated.  相似文献   

高挂山—牛头寨地区小型环形影象构造分析及其找矿意义     

钱惠林 《湖南地质》1989,8(2):18-22

高挂山—牛头寨地区,通过大比例尺航片解译,发现6个大小不等的小型环形影象信息。这些环形影象与岩浆活动、已知矿床、矿化点、重砂异常、物化探异常等的分布有着内在的联系。为预测找矿远景区和找隐伏矿床提供了影象依据。  相似文献   

Identifying linear and non-linear behaviour in reduced complexity modelling output using surrogate data methods     

C.J. Keylock   《Geomorphology》2007,90(3-4):356

Validation of model output is an important issue in the environmental sciences. This is particularly the case for reduced complexity modelling approaches where verification of the underlying equations is often problematic. Hence, methods that go beyond validation based on average values or the histogram of model output, are clearly advantageous. In this paper we show that a validation method based on the serial properties of time–space data, and developed in geomorphology, is a useful alternative but is nevertheless still insensitive to certain asymmetric characteristics of the signal. Hence, use of this method for validation may be enhanced by the adoption of an accompanying test for asymmetry in the model output.  相似文献   

Performance of a Reconfigured Atmospheric General Circulation Model at Low Resolution   总被引：3，自引：2，他引：3  

WEN Xinyu  ZHOU Tianjun  WANG Shaowu  WANG Bin  WAN Hui  LI Jian 《大气科学进展》2007,24(4):712-728

Paleoclimate simulations usually require model runs over a very long time.The fast integration version of a state-of-the-art general circulation model (GCM),which shares the same physical and dynamical processes but with reduced horizontal resolution and increased time step,is usually developed.In this study,we configure a fast version of an atmospheric GCM (AGCM),the Grid Atmospheric Model of IAP/LASG (Institute of Atmospheric Physics/State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics),at low resolution (GAMIL-L,hereafter),and compare the simulation results with the NCEP/NCAR reanalysis and other data to examine its performance.GAMIL-L,which is derived from the original GAMIL,is a finite difference AGCM with 72×40 grids in longitude and latitude and 26 vertical levels.To validate the simulated climatology and variability,two runs were achieved.One was a 60-year control run with fixed climatological monthly sea surface temperature (SST) forcing,and the other was a 50-yr (1950-2000) integration with observational time-varying monthly SST forcing.Comparisons between these two cases and the reanalysis,including intra-seasonal and inter-annual variability are also presented.In addition,the differences between GAMIL-L and the original version of GAMIL are also investigated. The results show that GAMIL-L can capture most of the large-scale dynamical features of the atmosphere, especially in the tropics and mid latitudes,although a few deficiencies exist,such as the underestimated Hadley cell and thereby the weak strength of the Asia summer monsoon.However,the simulated mean states over high latitudes,especially over the polar regions,are not acceptable.Apart from dynamics,the thermodynamic features mainly depend upon the physical parameterization schemes.Since the physical package of GAMIL-L is exactly the same as the original high-resolution version of GAMIL,in which the NCAR Community Atmosphere Model (CAM2) physical package was used,there are only small differences between them in the precipitation and temperature fields.Because our goal is to develop a fast-running AGCM and employ it in the coupled climate system model of IAP/LASG for paleoclimate studies such as ENSO and Australia-Asia monsoon,particular attention has been paid to the model performances in the tropics.More model validations,such as those ran for the Southern Oscillation and South Asia monsoon, indicate that GAMIL-L is reasonably competent and valuable in this regard.  相似文献   

A microscale three-dimensional urban energy balance model for studying surface temperatures   总被引：1，自引：2，他引：1  

E. Scott Krayenhoff  James A. Voogt 《Boundary-Layer Meteorology》2007,123(3):433-461

A microscale three-dimensional (3-D) urban energy balance model, Temperatures of Urban Facets in 3-D (TUF-3D), is developed to predict urban surface temperatures for a variety of surface geometries and properties, weather conditions, and solar angles. The surface is composed of plane-parallel facets: roofs, walls, and streets, which are further sub-divided into identical square patches, resulting in a 3-D raster-type model geometry. The model code is structured into radiation, conduction and convection sub-models. The radiation sub-model uses the radiosity approach and accounts for multiple reflections and shading of direct solar radiation. Conduction is solved by finite differencing of the heat conduction equation, and convection is modelled by empirically relating patch heat transfer coefficients to the momentum forcing and the building morphology. The radiation and conduction sub-models are tested individually against measurements, and the complete model is tested against full-scale urban surface temperature and energy balance observations. Modelled surface temperatures perform well at both the facet-average and the sub-facet scales given the precision of the observations and the uncertainties in the model inputs. The model has several potential applications, such as the calculation of radiative loads, and the investigation of effective thermal anisotropy (when combined with a sensor-view model).  相似文献   

Static and dynamic response of massive caisson foundations with soil and interface nonlinearities—validation and results     

Nikos Gerolymos  George Gazetas   《Soil Dynamics and Earthquake Engineering》2006,26(5):377-394

The static, cyclic, and dynamic response of a massive caisson foundation embedded in nonlinear layered or inhomogeneous soil and loaded at its top is investigated. The caisson is supported against horizontal displacement and rotation by four types of inelastic springs and dashpots, described with the BWGG model that was developed in the preceding companion paper [Gerolymos N, Gazetas G. Development of winkler model for static and dynamic response of caisson foundations with soil and interface nonlinearities. Soil Dyn Earthq Eng, submitted companion paper]. The prediction of the model is satisfactorily compared with results from 3D-finite element analysis. Some experimental corroboration of the method is provided with the help of a 1/3-scale lateral load test that had been conducted in the field by EPRI. An illustrative example of a caisson embedded in linearly-inhomogeneous clay and subjected to static and dynamic loading is analysed. Characteristic results are presented highlighting the role of soil inelasticity and its interplay with the two dominant interface nonlinearities: separation (gapping) of the caisson shaft from the surrounding soil, and uplifting of the base from the underlying soil.  相似文献   

南极中山站与北极地磁活动相关性研究   总被引：2，自引：0，他引：2       下载免费PDF全文

胡红桥  刘瑞源  杨惠根  刘顺林 《地球物理学报》2006,49(5):1321-1328

本文利用南极中山站和新奥尔松（NAL）等5个北极站2000年9月到2003年3月共719天的地磁观测数据，以20 min间隔内地磁北向水平分量的互相关系数大于09为判据，对南北极地磁活动相关的发生率进行了统计，并与T89地磁模型得到的中山站共轭位置的分布进行了比较. 结果表明，南北极地磁活动相关的发生率与台站位置、季节、地方时和地磁活动性有着密切的关系. 在北极的5个台站中朗伊尔站（LYR）与中山站地磁相关的时间最多（占17%）；在两分季发生相关的情况比冬季和夏季多；在傍晚发生相关的情况最多，中午发生相关的情况最少；地磁活动较强时，相关的情况比地磁宁静时更多一些.  相似文献   

Earthquake catalogues and modelling strategies. A new testing procedure for the comparison between competing models     

G. Grandori  E. Guagenti  L. Petrini 《Journal of Seismology》2006,10(3):259-269

In this paper we consider the procedures that, on the basis of an earthquake catalogue, yield the magnitude distribution function F _M (F _M generators). In particular, our attention is focused on the F _M generators that are currently used in the frame of the probabilistic seismic hazard analysis at a site. From an engineering point of view, the behaviour of F _M in the range of strong earthquakes is of crucial importance. On the other hand, in general, the statistical validation of F _M in that range is not feasible because of an insufficient number of strong earthquakes in available catalogues.Our investigation is limited to the problem of the comparison between competing F _M generators. We show that a simple empirical F _M generator (called the CFP generator) can be more reliable than generators based on mathematical models. The numerical experiments that support this statement regards two test-sites and two mathematical models of magnitude distribution, namely the truncated-exponential and the characteristic-type models.The main conclusion is the suggestion of a test (called the CFP-test) that can be summarized as follows. Let X be a site for which, with current criteria, a specific F _M ^X generator based on a mathematical model has been selected. At this point, following the comparison approach described in the paper, the F _M ^X generator is compared with the empirical CFP generator. It can happen (actually it happens in many of our numerical experiments) that this test indicates the CFP generator as more reliable than the selected F _M ^X generator.  相似文献