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41.
豫北多时效归一化棉铃虫气象预报模式 总被引:4,自引:0,他引:4
按照棉铃虫繁育规律,将棉铃虫周年活动期划分为秋季预蛹期、越冬期、春季羽化期、夏季危害期4个阶段,分阶段选取有昆虫学、统计学意义的气象因子,通过归一化处理和加权组合,组成棉铃虫气象指数,建立多时效、归一化棉铃虫气象预报模式和分析、评价指标。结果显示:气象条件与棉铃虫发生程度密切相关,各时段预报模式的复相关系数达0.7780~0.8780,回代拟合率为96.7%,回归效果极显著。经试报应用,取得较好效果。结论认为:将诸多气象因子作无量纲化处理,不但便于因子间相互组合,还可提高模式的预报精度;将棉铃虫周年繁育期划分为秋季预蛹期、越冬期、春季羽化期、夏季危害期,突出了阶段性特点,分阶段组建预报模式,预报效果较好。对组合因子的生物学意义,有待生物学试验认定。 相似文献
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含硬包体试样在破裂孕育过程中波速场的变化 总被引:2,自引:2,他引:0
含硬包体混凝土试样在底面支撑侧面双轴加压至主破裂的情况下波速场的变化图象为:加压初期,试样上的纵波平均速度在4175~4615m/s之间变化,随着压力升高,出现小于4175m/s的低速区,但范围甚小,位置在两个包体之间。随后出现大于4615m/s的高速区,范围大致与包体位置一致。随着σ1的增加,低速区在逐渐变大,高速区逐步减小后又重新变大,高速区与低速区在平面上相互重叠,在空间上看,高速区被低速区包围着。临近主破裂时,低速区变小并逐步形成条带,高速区也变小,主要集中在靠近未来出现破裂的一个包体位置上。最终的破裂面出现在此高速区与低速条带交界附近,包体也局部破裂了。 相似文献
44.
利用InSAR技术获取高寒高海拔地区高精度DEM 总被引:1,自引:1,他引:0
本文以Sentinel-1A SLC数据为原始影像,利用InSAR技术获取新疆西天山中部高寒高海拔地区小区域DEM,将获得的DEM与常用的SRTM v4 DEM和GDEMDEM进行对比分析。结果表明:利用InSAR技术处理Sentlnel-1A SLC数据可以获得分辨率为15 m的高精度DEM,该DEM数据精度优于SRTM v4 DEM和GDEMDEM,能更好地描绘地表地形细节,可作为输入数据获取地面高精度形变信息,为工程建设和地质灾害评价提供重要的基础数据。此外,该方法对DEM数据的更新也具有重大意义。 相似文献
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46.
Shili Yang Wenjie Dong Jieming Chou Jinming Feng Xiaodong Yan Zhigang Wei Wenping Yuan Yan Guo Yanli Tang Jiacong Hu 《大气科学进展》2015,32(12):1683-1688
Integrated assessment models and coupled earth system models both have their limitations in understanding the interactions between human activity and the physical earth system. In this paper,a new human–earth system model,BNUHESM1.0,constructed by combining the economic and climate damage components of the Dynamic Integrated Model of Climate Change and Economy to the BNU-ESM model,is introduced. The ability of BNU-HESM1.0 in simulating the global CO2 concentration and surface temperature is also evaluated. We find that,compared to observation,BNU-HESM1.0underestimates the global CO2 concentration and its rising trend during 1965–2005,due to the uncertainty in the economic components. However,the surface temperature simulated by BNU-HESM1.0 is much closer to observation,resulting from the overestimates of surface temperature by the original BNU-ESM model. The uncertainty of BNU-ESM falls within the range of present earth system uncertainty,so it is the economic and climate damage component of BNU-HESM1.0 that needs to be improved through further study. However,the main purpose of this paper is to introduce a new approach to investigate the complex relationship between human activity and the earth system. It is hoped that it will inspire further ideas that prove valuable in guiding human activities appropriate for a sustainable future climate. 相似文献
47.
在全球气候变暖的背景下,持续的干旱事件将对生态系统和人类社会产生不利影响。尽管存在多源卫星遥感资料及多种干旱指数,然而区域和全球尺度干旱事件的监测仍具有挑战。采用TRMM(Tropical RainfallMeasuring Mission)数据量化降水异常、MODIS(Moderate Resolution Imaging Spectroradiometer)归一化植被指数(Normalized Difference Vegetation Index,NDVI)和陆表温度(Land Surface Temperature,LST)数据表征植被生长异常,构建了一种兼顾降水异常和植被生长状况异常的多传感器陆表干旱严重程度指数(Multi-sensorsDrought Severity Index,MDSI)。结果表明:MDSI 能够准确检测准全球范围(50°S~50°N,0°~180°~0°)的气象干旱事件,如亚马逊流域2005 和2010 年干旱、中国川渝地区2006 年干旱、中国云南2010 年干旱、非洲东部2011 年干旱、2012 年美国中部干旱等;MDSI 与PDSI(Palmer Drought Severity Index)呈现出大致相同的干湿空间格局,并且MDSI 有助于湿润地区干旱程度的检测。 相似文献
48.
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??Ii-1????Ii?????????????в?????????????????????????????÷???????Ч??? 相似文献
49.
CMIP5/AMIP GCM simulations of East Asian summer monsoon 总被引:1,自引:0,他引:1
The East Asian summer monsoon (EASM) is a distinctive component of the Asian climate system and critically influences the economy and society of the region.To understand the ability of AGCMs in capturing the major features of EASM,10 models that participated in Coupled Model Intercomparison Project/Atmospheric Model Intercomparison Project (CMIP5/AMIP),which used observational SST and sea ice to drive AGCMs during the period 1979-2008,were evaluated by comparing with observations and AMIP Ⅱ simulations.The results indicated that the multi-model ensemble (MME) of CMIP5/AMIP captures the main characteristics of precipitation and monsoon circulation,and shows the best skill in EASM simulation,better than the AMIP Ⅱ MME.As for the Meiyu/Changma/Baiyu rainbelt,the intensity of rainfall is underestimated in all the models.The biases are caused by a weak western Pacific subtropical high (WPSH) and accompanying eastward southwesterly winds in group Ⅰ models,and by a too strong and west-extended WPSH as well as westerly winds in group Ⅱ models.Considerable systematic errors exist in the simulated seasonal migration of rainfall,and the notable northward jumps and rainfall persistence remain a challenge for all the models.However,the CMIP5/AMIP MME is skillful in simulating the western North Pacific monsoon index (WNPMI). 相似文献
50.
Impact of Anthropogenic Heat Release on Regional Climate in Three Vast Urban Agglomerations in China简 总被引:5,自引:0,他引:5
We simulated the impact of anthropogenic heat release (AHR) on the regional climate in three vast city agglomerations in China using the Weather Research and Forecasting model with nested high-resolution modeling.Based on energy consumption and high-quality land use data,we designed two scenarios to represent no-AHR and current-AHR conditions.By comparing the results of the two numerical experiments,changes of surface air temperature and precipitation due to AHR were quantified and analyzed.We concluded that AHR increases the temperature in these urbanized areas by about 0.5℃-1℃,and this increase is more pronounced in winter than in other seasons.The inclusion of AHR enhances the convergence of water vapor over urbanized areas.Together with the warming of the lower troposphere and the enhancement of ascending motions caused by AHR,the average convective available potential energy in urbanized areas is increased.Rainfall amounts in summer over urbanized areas are likely to increase and regional precipitation patterns to be altered to some extent. 相似文献