Diagnosis of a Severe Rainstorm Event Induced by Eastly Wave and Vortex in Off Southeast Coast of China          下载免费PDF全文

ZHENG Feng 《高原气象》2009,28(5):1058-1066

Using the NCEP reanalysis at 1° ×1° resolution in conjunction with satellite imagery, a study is undertaken of easterly wave related rainstorm events on August 3～4, 2001 in seaboards between northern Fujian and southern Zhejiang, expounding the scheme for computing helicity, and exploring the rainstorm evolution and the genesis of the Yandang mountains-triggered a meso-vortex (Duan and Chen, 2005) by means of helicity and Q vector divergence. Besides, MM5V2 is employed to simulate the easterly wave caused meso-vortex. Results show that the development of the central intensity and location of the high-valued helicity is well indicative of the fallout area and the genesis of the meso-vortex, discovering that the space/time evolutions of helicity serve as indicators of some utility for the rainfall occurrence; it is revealed that the calculated helicity is of higher precision than MM5V2 simulations in predicting the initial position and the track of the meso-vortex, with their combination contributing to the improvement of predicting the meso-vortex, also, the space/time evolutions in the superimposition of the zone of large-value helicity gradients upon that of high-value Q vector divergence gradients can be used to accurately forecast the rainstorm happening and initial position of the meso-vortex, thereby illustrating the higher ability of diagnosing the precipitation and its system in the superimposed region.  相似文献   

祁连山冬季降雪个例模拟分析(Ⅱ):人工催化试验   总被引：2，自引：1，他引：1       下载免费PDF全文

孙晶  楼小凤  史月琴  胡志晋 《高原气象》2009,28(3)

利用部分改进了的中尺度模式MM5V3对2006年2月7～8日甘肃北部地区一次冷云降雪过程进行了人工催化的数值试验,研究加入人工冰晶对祁连山北坡地区冷性层云降雪的影响.进行了不同剂量和不同高度的催化试验,详细分析了催化后的微物理过程和动力热力过程的变化.结果表明:累积降雪中心的上风方含有过冷云水的区域为催化潜力区.催化后累积降雪中心雪量增加,增雪区周围出现分散的减雪区.过冷云水最多并且最缺乏冰晶粒子的层次具有很好的催化条件.加人人工冰晶后消耗了水汽和过冷云水,冰晶和雪的量值均有所增加,雪碰并冰晶过程、冰品转化过程、凝华过程是雪增长的主要过程,相态变化引起的潜热增加导致升温和上升运动加强.这种变化同时使周围的垂直运动和水成物含量发生改变,周围的上升运动减弱,雪的含量减少,产生了减雪区.  相似文献   

Anthropogenic Direct Radiative Forcing of Tropospheric Ozone and Aerosols from 1850 to 2000 Estimated with IPCC AR5 Emissions Inventories          下载免费PDF全文

CHANG Wen-Yuan  LIAO Hong 《大气和海洋科学快报》2009,2(4):201-207

This study estimates direct radiative forcing by tropospheric ozone and all aerosols between the years 1850 and 2000, using the new IPCC AR5 （the Intergovernmental Panel on Climate Change Fifth Assessment Report） emissions inventories and a fully coupled chemistry-aerosol general circulation model. As compared to the previous Global Emissions Inventory Activity （GEIA） data, that have been commonly used for forcing estimates since 1990, the IPCC AR5 emissions inventories report lower anthropogenic emissions of organic carbon and black carbon aerosols and higher sulfur and NOx emissions. The simulated global and annual mean burdens of sulfate, nitrate, black carbon （BC）, primary organic aerosol （POA）, secondary organic aerosol （SOA）, and ozone were 0.79, 0.35, 0.05, 0.49, 0.34, and 269 Tg, respectively, in the year 1850, and 1.90, 0.90, 0.11, 0.71, 0.32, and 377 Tg, respectively, in the year 2000. The estimated annual mean top of the atmosphere （TOA） direct radiative forcing of all anthropogenic aerosols based on the AR5 emissions inventories is -0.60 W m^-2 on a global mean basis from 1850 to 2000. However, this is -2.40 W m-2 when forcing values are averaged over eastern China （18-45°N and 95-125°E）. The value for tropospheric ozone is 0.17 W m^-1 on a global mean basis and 0.24 W m^-2 over eastern China. Forcing values indicate that the climatic effect of aerosols over eastern China is much more significant than the globally averaged effect.  相似文献   

中国中东部MODIS与MISR气溶胶光学厚度的对比   总被引：5，自引：2，他引：3  

张莹  孙照渤 《气象科学》2010,30(1):48-54

Terra/MODIS前一版本C4和最新版本C5的气溶胶光学厚度(AOT Aerosol OpticalThickness)数据,以及搭载于同一卫星上的Terra/MISR气溶胶光学厚度数据,在中国中东部地区存在差异。本文利用AERONET气溶胶光学厚度数据对以上三种资料验证的结果表明:MODIS气溶胶算法改进之后得到的C5 AOT数据较C4精度确有很大提高,且优于MISR的AOT数据。  相似文献   

从哥本哈根气候变化大会看气候变化谈判的焦点问题及IPCC第五次评估报告的可能作用   总被引：2，自引：0，他引：2       下载免费PDF全文

高云  罗勇  张军岩 《气候变化研究进展》2010,6(2):83-88

从哥本哈根气候变化大会的谈判焦点可以预期,后续国际气候变化谈判的重点将是谈判的基础案文、发达国家在《京都议定书》第二承诺期进一步的量化减排承诺以及长期目标的表述等问题。IPCC第五次评估报告将对以往报告已阐述的科学问题和基本结论加以巩固并提供更有说服力的证据和论据,更加侧重区域问题,增加适应和减缓经济学成本、气候变化与可持续发展等内容的分析。关于气候变化检测和归因、气候变化影响和关键脆弱性、大气温室气体浓度稳定水平、适应的选择及其成本效益、减缓措施的选择和社会经济成本、责任分担机制及公平性等问题的评估结论,将对谈判进程的推进发挥重要作用。  相似文献   

A search for decay of with tin-loaded liquid scintillator     

M.J. Hwang  Y.J. Kwon  H.J. Kim  J.W. Kwak  S.C. Kim  S.K. Kim  T.Y. Kim  S.Y. Kim  H.S. Lee  M.J. Lee  S.S. Myung  Y.D. Kim  J.I. Lee  W.G. Kang  I.S. Hahn  M.H. Lee  KIMS Collaboration 《Astroparticle Physics》2009,31(6):412-416

A search for the neutrinoless double-beta decay of ¹²⁴Sn was carried out using the tin-loaded liquid scintillator for an active source-detector technique. Tin (32.6%) in weight was successfully loaded into the liquid scintillator, and light output was as high as 57% of the unloaded liquid scintillator. A tin-loaded liquid scintillator with 1.1 ℓ volume was installed at the 700 m underground laboratory in YangYang, and data were taken for 5285 h. No evidence for the 0νββ decay was found and a lower limit on the ¹²⁴Sn half-life was obtained to be 2.0×10¹⁹ year with 90% C.L. The new limit represents a significant improvement with respect to those previously available for ¹²⁴Sn.  相似文献   

Search for TeV gamma-rays from Geminga pulsar     

B.B. Singh  V.R. Chitnis  D. Bose  M.A. Rahman  S.S. Upadhya  K.S. Gothe  B.K. Nagesh  P.N. Purohit  Shobha K. Rao  Kamesh K. Rao  S.K. Sharma  P.V. Sudersan  B.L. Venkateshmurthy  P.R. Vishwanath  B.S. Acharya 《Astroparticle Physics》2009,32(2):120-128

We present the results of observation of the Geminga pulsar carried out in the TeV energy band during the 6 year period spanning 2000–2006 using the Pachmarhi Array of Cherenkov Telescopes (PACT). A long stretch of data, new computer codes and the “Tempo” package have been used in the present analysis. We have searched for evidence of pulsed emission of γ-rays from the Geminga pulsar using the post-glitch pulsar elements obtained by Jackson and Halpern from X-ray/γ-ray satellite data. We do not see any significant evidence for pulsed emission from the Geminga pulsar at a threshold energy of 825 GeV. In this paper we present our results on the light curve in the TeV energy band, set an upper limit on the time averaged flux of γ-rays, and compare our results with other ground based observations.  相似文献   

SPOT-5图像在西藏亚东县康布曲流域综合治理中的应用   总被引：2，自引：0，他引：2  

卢中正  吴君丽  张峰 《地质灾害与环境保护》2005,16(2):186-189

以西藏亚东县为例,借助ERDASimagine、PCIGeomatic、Arc／INFO、MiCrostation等软件,研究了SPOT-5遥感数据在康布曲流域综合治理中的应用,运用了数字图像融合方法和图像增强技术,制作该区1：1万假彩色图像,并在此基础上对康布曲流域地形地貌、土地利用、植被类型、水土流失和地质灾害等进行了遥感调查,取得了良好的效果。为该区综合治理提供基础资料。  相似文献   

SPOT5在矿山监测中的应用   总被引：13，自引：0，他引：13  

况顺达  赵震海 《地质与勘探》2005,41(3):79-82

为了快速监控矿山的实际开采情况与矿山的登记现状之间的差异,维护矿产资源管理秩序,打击无证采矿、越界采矿,保护生态环境,促进依法办矿和科学办矿,先利用SPOT5图像进行目标确定,然后野外检查.通过研究发现,利用遥感手段对煤矿、砂石(建筑用材料)、铝土矿等矿山的监测效果明显.  相似文献   

Monazite-Xenotime Thermochronometry and Al2SiO5 Reaction Textures in the Picuris Range, Northern New Mexico, USA: New Evidence for a 1450-1400 Ma Orogenic Event     

DANIEL  CHRISTOPHER G.; PYLE  JOSEPH M. 《Journal of Petrology》2006,47(1):97-118

Al₂SiO₅ reaction textures in aluminous schist and quartziteof the northern Picuris range, north-central New Mexico, recorda paragenetic sequence of kyanite to sillimanite to andalusite,consistent with a clockwise P–T loop, with minor decompressionnear the Al₂SiO₅ triple-point. Peak metamorphic temperaturesare estimated at 510–525°C, at 4·0–4·2kbar. Kyanite and fibrolite are strongly deformed; some prismaticsillimanite, and all andalusite are relatively undeformed. Monaziteoccurs as inclusions within kyanite, mats of sillimanite andcentimetre-scale porphyroblasts of andalusite, and is typicallyaligned subparallel to the dominant regional foliation (S₀/S₁or S₂) and extension lineation (L₁). Back-scatter electron imagesand X-ray maps of monazite reveal distinct core, intermediateand rim compositional domains. Monazite–xenotime thermometryfrom the intermediate and rim domains yields temperatures of405–470°C (±50°C) and 500–520°C(±50°C), respectively, consistent with the progradeto peak metamorphic growth of monazite. In situ, ion microprobeanalyses from five monazites yield an upper intercept age of1417 ± 9 Ma. Near-concordant to concordant analyses yield²⁰⁷Pb–²⁰⁶Pb ages from 1434 ± 12 Ma (core) to 1390± 20 Ma (rim). We find no evidence of older regionalmetamorphism related to the 1650 Ma Mazatzal Orogeny. KEY WORDS: Al₂SiO₅; metamorphism; monazite; thermochronometry; triple-point  相似文献