基于多源数据的城市热岛效应研究——以石家庄地区为例   总被引：3，自引：1，他引：2  

杨鹏  陈静  侯晓玮  高祺  赵强 《气象》2013,39(10):1304-1313

以石家庄地区为研究对象,选取地面气象观测站数据、区域自动站数据、MODIS 1B以及Landsat7 ETM+卫星遥感影像数据作为主要数据源,从气温和地表温度两个角度考虑,分析城市化进程对城市热岛效应的影响,城市热岛的时间变化规律以及空间分布规律等。研究结果表明：(1)石家庄城市热岛强度随时间逐年增加且呈继续上升趋势,与城市化进程呈同步变化趋势;(2)采用同一时次气温和地表温度资料分别研究石家庄城市热岛空间分布特征,发现夏、秋季白天和四季晚上石家庄城市热岛效应明显,春、冬季白天有时出现“冷岛”效应;(3)与白天相比,在晚上气温和地表温度两者的相关性较好,其相关系数可达0.80;(4)选用Landsat7 ETM+高分辨率卫星遥感影像数据研究不同土地覆盖类型对城市热岛的影响,发现地表温度随着植被指数NDVI的增大而减小,两者之间呈现很好的负相关性,R2=0.72。  相似文献   

“12.7.21”西南涡极端强降雨的成因分析   总被引：2，自引：1，他引：1  

陈贵川  谌芸  张勇  陈鹏  王欢  黎中菊  刘念  翟丹华  龙美希 《气象》2013,39(12):1529-1541

利用常规观测资料、ECMWF分析场、区域自动站、多普勒雷达及SWAN系统产品等资料对2012年7月21日西南涡暴雨过程及盘龙极端强降雨进行分析。分析发现：此次过程是“北槽南涡”形势下,地面冷空气触发西南涡其东侧辐合上升运动强烈发展,高层强辐散,因而产生了对流性暴雨天气过程;冷空气从西侧侵入西南涡是925 hPa “S”形冷锋形成的直接原因,也是地面辐合线形成的重要因素;极端短时强降雨就发生在西南涡东侧中尺度雨带的中部偏北区域,有地面辐合线相配合,降雨最强时MCC冷云中心TBB达最低值。雷达回波表明：西南涡两侧冷暖空气的交绥促进了β中尺度气旋式环流的形成;偏南风低空急流为强降雨提供了充足的水汽,增强了中低层的垂直风切变,有利于强降水超级单体风暴的发展和维持;盘龙的极端短时强降雨是β中尺度气旋式环流中,伴随有深厚中气旋的强降水超级单体风暴在环流中心附近持续发展的结果。  相似文献   

FY2海面温度产品质量检验方法与误差分析   总被引：2，自引：0，他引：2  

王素娟  陆风  张鹏  张晓虎  崔鹏  王维和 《气象》2013,39(10):1331-1336

主要介绍了风云二号静止气象卫星海面温度产品的质量检验方法及检验流程,给出了FY2E业务海面温度产品和FY2F海面温度算法的质量检验结果,并从误差统计、反演算法、系统设计等方面分析了目前FY2海面温度产品与国外卫星海面温度产品差异大的原因。现场海面温度质量检验和分析场海面温度交叉检验各有优缺点。现场海面温度质量检验能够对FY2 SST产品给于客观的评价。国外分析场海面温度具有时效性好、全球覆盖且质量均一的优点,分析场海面温度交叉检验能满足FY2 SST质量检验的时效性,是对FY2 SST的相对检验。通过静止卫星海面温度产品质量检验信息可以为产品研发人员和相关用户提供参考。  相似文献   

省级气象宽带网可靠性设计          下载免费PDF全文

陈晓宇  张永华  吴兆雄  王佳  孙鹏 《应用气象学报》2013,24(6):761-768

气象业务的发展和社会需求的增长,对广域宽带网络系统提出更高要求,不但要求传输的数据量大,时效性强,而且要求其可靠性高。目前各省级气象局的宽带网可靠性设计,大都采用降级备份,无法做到双链路自动切换、无缝备份,难以满足气象业务7×24 h从不间断的实际需求,网络可靠性有待进一步提高。该文提出一种基于双向转发检测 (BFD) 和策略路由技术的网络可靠性设计方案,应用该方案不仅使网络结构和带宽有大幅提升,还能实现业务分流、链路冗余和故障自动切换,提高气象宽带网的可靠性水平。该方案经严格测试后,已依托广东省气象宽带网得以实现并投入业务运行,效果良好。同时,该设计对其他省级气象网络建设有一定参考价值。  相似文献   

Improved reliability of ENSO hindcasts with multi-ocean analyses ensemble initialization     

Jieshun Zhu  Bohua Huang  Magdalena A. Balmaseda  James L. Kinter III  Peitao Peng  Zeng-Zhen Hu  Lawrence Marx 《Climate Dynamics》2013,41(9-10):2785-2795

Currently, ensemble seasonal forecasts using a single model with multiple perturbed initial conditions generally suffer from an “overconfidence” problem, i.e., the ensemble evolves such that the spread among members is small, compared to the magnitude of the mean error. This has motivated the use of a multi-model ensemble (MME), a technique that aims at sampling the structural uncertainty in the forecasting system. Here we investigate how the structural uncertainty in the ocean initial conditions impacts the reliability in seasonal forecasts, by using a new ensemble generation method to be referred to as the multiple-ocean analysis ensemble (MAE) initialization. In the MAE method, multiple ocean analyses are used to build an ensemble of ocean initial states, thus sampling structural uncertainties in oceanic initial conditions (OIC) originating from errors in the ocean model, the forcing flux, and the measurements, especially in areas and times of insufficient observations, as well as from the dependence on data assimilation methods. The merit of MAE initialization is demonstrated by the improved El Niño and the Southern Oscillation (ENSO) forecasting reliability. In particular, compared with the atmospheric perturbation or lagged ensemble approaches, the MAE initialization more effectively enhances ensemble dispersion in ENSO forecasting. A quantitative probabilistic measure of reliability also indicates that the MAE method performs better in forecasting all three (warm, neutral and cold) categories of ENSO events. In addition to improving seasonal forecasts, the MAE strategy may be used to identify the characteristics of the current structural uncertainty and as guidance for improving the observational network and assimilation strategy. Moreover, although the MAE method is not expected to totally correct the overconfidence of seasonal forecasts, our results demonstrate that OIC uncertainty is one of the major sources of forecast overconfidence, and suggest that the MAE is an essential component of an MME system.  相似文献   

基于Voronoi图的强降水过程空间非均匀性定量表征方法     

彭小燕  杜银  丁裕国 《气象科技》2013,41(3):522-528

利用Voronoi\\Delaunay图模型影响范围和局部动态的特性,提出一种基于动态边界定量提取强降水过程空间非均匀分布特征的新方法,根据1959—2002年中国740站逐日降水资料,构建5日、10日两种时间尺度区域持续性年极端强降水过程序列,用以检验该方法的应用效果,并应用该方法分析了5日(10日)区域持续性年极端强降水过程空间非均匀分布特征及其演变规律。结果表明：与传统的数量统计方法和区域插值方法相比,该方法在强降水空间分布中心、过程内不同强度降水覆盖区域、降水集中区等的定量度量方面具有更高的分辨力和较好实际应用价值;气候趋势分析中在1959—2002年间,5日区域持续性年极端强降水过程出现日期有明显提前趋势。  相似文献   

温室黄瓜低温气象灾害指标   总被引：4，自引：0，他引：4  

彭晓丹  杨再强  柳笛  张婷华  周志龙  朱凯  赵翔 《气象科技》2013,41(2):394-400

以黄瓜品种津优35号(Jingyou 35)为试材,于2011年设计不同低温（5、7、9、11 ℃,以25 ℃为对照）处理的人工环境控制试验,系统研究不同低温胁迫对黄瓜叶片光合作用特性及抗氧化酶活性的影响。结果表明：黄瓜叶片最大光合速率随低温胁迫程度的增加依次降低;在不同低温胁迫下,随胁迫时间的延长,黄瓜叶片光补偿点不断升高,光饱和点不断降低;在5 ℃、7 ℃和9 ℃低温处理下,随胁迫时间的延长,光系统Ⅱ最大光化学效率呈下降趋势,光化学淬灭不断降低,非光化学淬灭的变化趋势相反;黄瓜叶片中的超氧化物歧化酶活性随着处理温度的降低先升高后下降;过氧化物酶活性在9 ℃处理24 h后达到最高;过氧化氢酶活性随着处理温度的降低而升高;丙二醛含量大于对照,随胁迫程度的增加先升高,后略有下降。通过研究建立了温室黄瓜低温气象灾害指标,划分为4个等级,分别为轻度、中度、重度和极重,可为设施农业气象服务提供科学依据。  相似文献   

On shallow-water bottom reverberation frequency dependence     

Cable  P.G. Yudichak  T.W. Dorfman  Y. Knobles  D.P. Renhe Zhang Zhaohui Peng Fenghua Li Zhenglin Li 《Oceanic Engineering, IEEE Journal of》2006,31(1):145-155

Determinations of bottom scattering strength in the decade below 1 kHz under downward refracting conditions have been made using acoustic reverberation and transmission data from the 2001 East China Sea Asian Seas International Acoustic Experiment (ASIAEX). The measurements were performed using explosive sources and receiving hydrophones in ship-suspended vertical-line arrays. The focus of this paper has been the dependence of bottom scattering strength on the frequency and characterization of the uncertainties associated with the extraction of scattering strength from reverberation. The derived bottom scattering strength gradually rises with frequency from 100-300 Hz and then more rapidly above 300 Hz. A potential explanation suggests that the frequency variation results from two scattering mechanisms, rough layer scattering at the low end of the band and sediment near-surface volume scattering at the high end. The spatial extrapolation of these results is explored by comparing them with similarly derived scattering strengths using data obtained under the Navy's Harsh Environments Program at a somewhat separated site (56 km) under environmental conditions similar to those during ASIAEX. In the ASIAEX analysis, it has been found that the largest source of uncertainty in the scattering-strength frequency dependence arises from persistence of finite-amplitude effects associated with the source signal.  相似文献   

Disk Galaxies with Finite Thickness     

Qiu-He Peng  Fang Peng  Chih-Kang Chou  Yi-Hui Lin 《Astrophysics and Space Science》2002,282(3):499-525

The effect of finite thickness on the properties of disk galaxies is calculated on the basis of a rigorous mathematical treatment in terms of Green function and Bessel Fourier transformation. In our approach, the mass of the galactic halo is determined by fitting the observed rotation curve with a five-component model. We not only choose a bulge, a thin disk and a halobut also include a nuclear bulge (i.e. the Galactic Nucleus) and a thick disk. The effect of finite thickness of the disk on both the radial and vertical self-gravity is considered in detail. The vertical dynamics of this three-dimensional system is also investigated.  相似文献   

硫化物吸附金属离子的实验研究──Ⅱ．温度与介质条件的影响     

吴大清  彭金莲  陈国玺 《地球化学》1996,(3)

合成ＰｂＳ和ＺｎＳ对Ａｇ２＋、Ｃｕ２＋、Ｃｄ２＋、Ｆｅ２＋、Ｍｎ２＋、Ｍｇ２＋、Ｓｂ２＋和Ｂｉ３＋等离子吸附量与温度关系的实验研究表明，其遵从Ｋｅｌｖｉｎ公式：在Ａ类吸附，即抗衡离子交换型吸附中，温度上升，其吸附量升降由反应热决定，本实验中Ａ类吸附多为上升型；而大部分Ｂ和Ｃ类吸附，即朗谬尔型及反朗谬尔型的吸附量则随温度上升呈指数下降。例外的仅有ＰｂＳ对Ｂｉ３＋离子的吸附，其吸附量随温度上升有微弱的上升。这可能与Ｂｉ３＋离子和吸附剂ＰｂＳ之间共晶反应和铅的铋硫盐的形成有关。Ａ类吸附的吸附量受介质条件变化影响很少。但对Ｂ和Ｃ类吸附，吸附量受ｐＨ和离子强度变化影响取决于三个因素：①吸附剂ＰｂＳ、ＺｎＳ表面电荷特性；②溶液介质条件变化时吸附离子在溶液中离子态的分布与变化；③被吸附离子在吸附剂中扩散和形成化合物或共晶的能力。因此，当ｐＨ增加时，Ｐｂｓ和ＺｎＳ对金属离子吸附量的变化表现出多样性：增加的有ＰｂＳ对Ｆｅ２＋离子的吸附；下降的有ＰｂＳ对Ｓｂ３＋离子的吸附和ＺｎＳ对Ｆｅ２＋、Ｍｎ２＋离子的吸附；不变的有ＰｂＳ对Ｂｉ３＋、Ｚｎ２＋离子的吸附和ＺｎＳ对Ｍｇ２＋离子的吸附。当溶液中离子强度增加时，由于溶液中自由态离子  相似文献