Analysis on spatiotemporal variation and influencing factors of net primary productivity in the Southern Ocean          下载免费PDF全文

Wu Yueyuan  Hou Shugui  Wu Shuangye  Pang Hongxi  Liu Ke  Yu Jinhai 《极地研究》1988,31(3):322

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The 3-hour-interval prediction of ground-level temperature in South Korea using dynamic linear models     

Keon-Tae SOHN  Deuk-Kyun RHA  Young-Kyung SEO 《大气科学进展》2003,20(4):575-582

The 3-hour-interval prediction of ground-level temperature from 00 h out to 45 h in South Korea(38 stations) is performed using the DLM (dynamic linear model) in order to eliminate the systematic error of numerical model forecasts. Numerical model forecasts and observations are used as input values of the DLM. According to the comparison of the DLM forecasts to the KFM (Kalman filter model) forecasts with RMSE and bias, the DLM is useful to improve the accuracy of prediction.  相似文献   

中国强震动观测展望   总被引：15，自引：1，他引：14  

李山有  金星  刘启方  孔戈 《地震工程与工程振动》2003,23(2):1-7

强震动观测是震灾预防与地震应急的重要基础。本在系统总结强震动观测的国际现状与发展趋势的基础上,结合我国的防震减灾实际需要和经济实力,提出了我国未来十年强震动观测的发展规划。  相似文献   

砂岩型铀矿成矿预测评价信息系统研究     

谢迎春  薛重生  李名松  江民忠 《地质科技情报》2003,22(3):73-76

基于Arcview3．2a平台的二次开发工具,采用Avenue和Microsoft VB6．0语言,设计开发了地漫砂岩型铀矿成矿预测评价信息系统。信息平台应用地理信息系统(GIS)强大的空间分析功能以及空间和属性数据的管理和查询功能,以某盆地的控矿地质、盆地构造、地质异常多深信息数据为例,建立了砂岩型铀矿成矿预测评价信息系统。系统对该盆地的地质、遥感、地球物理数据进行了基于空间分析和成矿预测的数据处理,圈定出14片远景区,其中4号远景区已钻探见矿。该系统的开发成功对铀矿的成矿预测评价进入数字化、信息化和可视化的空间信息处理具有重要的试验意义。  相似文献   

Geostatistical mapping of geomorphic variables in the presence of trend     

R. M. Lark  R. Webster 《地球表面变化过程与地形》2006,31(7):862-874

Mapping geomorphic variables geostatistically, specifically by kriging, runs into difficulties when there is trend. The reason is that the variogram required for the kriging must be of residuals from any trend, which in turn cannot be estimated optimally by the usual method of trend surface analysis because the residuals are correlated. The difficulties can be overcome by the use of residual maximum likelihood (REML) to estimate both the trend and the variogram of the residuals simultaneously. We summarize the theory of REML as it applies to kriging in the presence of trend. We present the equations to show how estimates of the trend are combined with kriging of residuals to give empirical best linear unbiased predictions (E‐BLUPs). We then apply the method to estimate the height of the sub‐Upper‐Chalk surface beneath the Chiltern Hills of southeast England from 238 borehole data. The variogram of the REML residuals is substantially different from that computed by ordinary least squares (OLS) analysis. The map of the predicted surface is similar to that made from kriging with the OLS variogram. The variances, however, are substantially larger because (a) they derive from a variogram with a much larger sill and (b) they include the uncertainty of the estimate of the trend. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Meteorological monitoring of an active volcano: Implications for eruption prediction     

Jenni Barclay  Jade E. Johnstone  Adrian J. Matthews   《Journal of Volcanology and Geothermal Research》2006,150(4):241-358

Rainfall data collected on and around the Soufriere Hills Volcano, Montserrat between 1998 and 2003 were analysed to assess the impact on primary volcanic activity, defined here as pyroclastic flows, dome collapses, and explosions. Fifteen such rainfall-triggered events were identified. If greater than 20 mm of rain fell on a particular day, the probability of a dome collapse occurring on that day increased by a factor of 6.3% to 9.2%, compared to a randomly chosen day. Similarly, the probability of observing pyroclastic flows and explosions on a day with > 20 mm of rainfall increased by factors of 2.6 and 5.4, respectively. These statistically significant links increased as the rainfall threshold was increased. Seventy percent of these rainfall-induced dome collapse episodes occurred on the same calendar day (most within a few hours) as the onset of intense rainfall, but an extra 3 occurred one or two calendar days later. The state of the volcano was important, with the rainfall–volcanic activity link being strongest during periods of unstable dome growth and weakest during periods of no dome growth or after a recent major collapse.Over 50% of the heavy rain days were associated with large-scale weather systems that can potentially be forecast up to a few days ahead. However, the remaining heavy rain days were associated with small-scale, essentially unpredictable weather systems. There was significant variability in the amount of rainfall recorded by different rain gauges, reflecting topographic variations around the volcano but also the inherent small-scale variability within an individual weather system. Hence, any monitoring/warning program is recommended to use a network, rather than just a single gauge. The seasonal cycle in rainfall was pronounced, with nearly all the heavy rain days occurring in the May–December wet season. Hence, the dome was at its most vulnerable at the beginning of the wet season after a period of uninterrupted growth. Interannual variability in rainfall was related to tropical Pacific and Atlantic sea surface temperature anomalies, and holds out the prospect of some limited skill in volcanic hazard forecasts at even longer lead times.  相似文献   

潞西盆地浅层地下水脆弱性预测分析     

魏海霞  薛传东  高照忠 《云南地质》2006,25(4):498-504

运用DRASTIC方法，评价潞西盆地浅层地下水脆弱性，结合区内人类工程活动因子。对潞西盆地远期地下水脆弱性进行预测分析，成果可为区内土地规划、备用水源地的选择、垃圾填埋场的选址及实现水资源可持续利用提供合理依据。  相似文献   

基于改进的Elman神经网络的中长期径流预报   总被引：2，自引：0，他引：2  

屈亚玲  周建中  刘芳  杨俊杰  李英海 《水文》2006,26(1):45-50

径流中长期预报长期以来一直都是人们关注的热点研究问题。现行的径流预报方法很多,传统的有时间序列法,多元回归分析法等,这些方法虽然简单易用,但是如果预报对象提供的样本容量偏小或者因子选择不够合理,都会造成预报精度偏差过大,难于有效的指导工程应用。鉴于此,本文提出一种改进的采用局部回归的Elman神经网络方法。并应用到凤滩水库优化调度的径流预报中。结果表明,与回归分析法、BP网络相比较,该方法不仅提高了算法的效率,而且提高了预报的精度,在径流预报中具有有效性和优越性。  相似文献   

洪水预报信息利用问题研究与讨论   总被引：8，自引：0，他引：8  

包为民 《水文》2006,26(2):18-21

分析了洪水预报研究现状,讨论了实时洪水预报系统研究中信息利用方面存在的问题,提出了值得进一步研究的关键性问题、研究思路和研究技术路线。  相似文献   

广西季风暴雨中期预报平台研制思路与应用     

李向红  蒋丽娟  薛荣康  黄嘉宏 《气象》2006,32(5):110-115

利用1980--2001年NCEP和TBB资料，采用逐例与合成分析相结合的方法，分析了夏季风影响期间广西大范围暴雨发生前各层天气系统和盂加拉湾强对流云团的配置演变，发现暴雨前盂加拉湾强对流发展和经向风加强等特征，并确立了广西大范围暴雨的高低层环流背景场和预报指标。将T213资料与NCEP资料进行线性趋势估计，建立了广西季风暴雨中期预报平台，试用效果较好。  相似文献