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951.
利用NOAA/AVHRR气象卫星实时监测到的洪涝灾害数据与GIS技术结合,以地理信息系统软件ArcView3.1为依托建立洪涝灾害遥感救援系统。在洪涝灾害发生时,依托本系统的数据库能快速、准确地提供通往淹没区的最佳救援路径,可快速地到达受灾区域,进行人员财产抢救及救援物资输送,为宏观决策提供了科学的依据。 相似文献
952.
人类活动对气候影响的研究Ⅱ.对东亚和中国气候变化的影响 总被引:15,自引:6,他引:15
系统总结和介绍了20世纪90年代以来作者所开展的有关人类活动对东亚和中国气候影响的一系列研究活动.其中包括温室气体辐射强迫及其气候效应,大气微量气体的全球增温潜能,对流层和平流层气溶胶的辐射气候效应,气候系统外部因子对中国气候影响的总体评估,人类活动对中国和东亚地区未来气候变化的影响,以及20世纪和21世纪东亚及中国的气候变化.同时给出了一系列研究成果,这些研究成果对于正确认识和准确预测东亚地区以及中国气候变化具有十分重要的意义. 相似文献
953.
954.
针对目前中尺度数值模式MM5所用初始场局限于NCEP和T213的现状,提出了应用日本数值预报产品(JMA,下同)格点资料做初始场的想法,并对试验过程进行了介绍。对台风Ranan im(0414)登陆浙江的路径、移速、强度和降水等方面的数值模拟结果表明,应用了JMA资料的MM5模式在原有基础上提高了预报精度,尤其在台风登陆时间和登陆地点上提高更为明显。 相似文献
955.
Aircraft turbulence data from the Autonomous Ocean Sampling Network project were analyzed and compared to the Coupled Ocean–Atmosphere
Response Experiment (COARE) bulk parametrization of turbulent fluxes in an ocean area near the coast of California characterized
by complex atmospheric flow. Turbulent fluxes measured at about 35 m above the sea surface using the eddy-correlation method
were lower than bulk estimates under unstable and stable atmospheric stratification for all but light winds. Neutral turbulent
transfer coefficients were used in this comparison because they remove the effects of mean atmospheric conditions and atmospheric
stability. Spectral analysis suggested that kilometre-scale longitudinal rolls affect significantly turbulence measurements
even near the sea surface, depending on sampling direction. Cross-wind sampling tended to capture all the available turbulent
energy. Vertical soundings showed low boundary-layer depths and high flux divergence near the sea surface in the case of sensible
heat flux but minimal flux divergence for the momentum flux. Cross-wind sampling and flux divergence were found to explain
most of the observed discrepancies between the measured and bulk flux estimates. At low wind speeds the drag coefficient determined
with eddy correlation and an inertial dissipation method after corrections were applied still showed high values compared
to bulk estimates. This discrepancy correlated with the dominance of sea swell, which was a usually observed condition under
low wind speeds. Under stable atmospheric conditions measured sensible heat fluxes, which usually have low values over the
ocean, were possibly affected by measurement errors and deviated significantly from bulk estimates. 相似文献
956.
957.
958.
Trace Metal Solid State Speciation in Aerosols of the Northern Levantine Basin,East Mediterranean 总被引:3,自引:0,他引:3
Mustafa Koçak Nilgun Kubilay Barak Herut Malcolm Nimmo 《Journal of Atmospheric Chemistry》2007,56(3):239-257
An established three stage sequential leach scheme was applied to a series of selected high volume aerosol samples (n = 35) collected from the Turkish Eastern Mediterranean coastline (Erdemli). Samples were selected according to their air
mass back trajectory history to reflect the contrasting mixtures of aerosol material present in the Eastern Mediterranean
marine aerosol. Two populations were adopted, those samples which were classed as “anthropogenic” and those which were “Saharan”
dominated aerosol populations. Applying the three stage leach it was possible to define the proportion for each of the considered
metals (Al, Fe, Cu, Pb, Cd, Zn and Mn) present in the (a) “exchangeable” (b) “carbonate / oxide” and (c) “refractory” phases,
representing novel solid state aerosol speciation data for this marine system. Clear trends were established, conforming with
data from previous studies with mainly crustal derived metals (Al and Fe) being present in the refractory phases (Al > 88%;
Fe > 84%) and those influenced by anthropogenic sources being dominating in the exchangeable phase, although for these metals
the variability was comparatively high (12–64%; 19–85%; 40–100% for Zn, Pb and Cd, respectively). For the majority, greater
exchangeable fractions were present the lower the crustal source contribution to the aerosol population, whereas the “refractory”
fraction exhibited contrasting behaviour. This was illustrated by the novel application of the mixing diagram, presenting
each of the three speciation stages against the corresponding percent anthropogenic contribution to each collected sample.
Zn, Pb and Cd all illustrated progressive decrease in the percent exchangeable with increasing crustal contribution to the
aerosol population. The percent exchangeable was discussed in terms of its use to represent the upper limit of the bioavailable
fraction of metal associated with the aerosol, post deposition. The mixing diagram approach enabled the prediction of the
residual fractions for Cd, Pb and Zn (41 ± 4%; 62 ± 4% and 82 ± 5%, respectively,) in Saharan end-member material. 相似文献
959.
基于GIS的安徽省重大农业气象灾害测评系统 总被引:15,自引:0,他引:15
以安徽省重大农业气象灾害的气候规律分析及遥感监测方法的基础,利用地理信息系统技术,设计并建立了省级农业气象灾害测评系统。该系统运用结构化设计原理,根据用户需求及系统建设的基本目标,确定了系统结构及主要功能,以为主要支撑软件,建立了安徽省干旱,洪涝及低温冷害的基本数据库、灾害监测评估模型和应急反应及决策服务系统。 相似文献
960.
根据1958-2008年华南48站降水资料、NOAA全球逐月海温格点资料、NCEP/NCAR再分析资料,采用EOF分解、相关、合成等统计方法,分析了华南夏季降水的变化特征及其与冬季热带太平洋海温的关系。结果表明,华南夏季降水变化特征主要表现为,空间分布以全区一致型为主,其次是南北反相对称型和东西反相对称型,且这3种分布模态都表现出显著的年际和年代际特征。全区一致型降水异常与热带太平洋海温显著相关,二者的相关性也具有年代际变化特征,其对应的热带太平洋海温具有沿赤道太平洋呈“负-正-负”的纬向分布型,类似于中部型El Nino。全区降水偏多时期,西南季风偏强,西太平洋副热带高压偏强、脊点位置偏西,南亚高压偏强、脊点位置偏东,总体的环流形势有利于华南地区的水汽输送和上升运动;降水偏少时期,情况相反。 相似文献