Vertical profiles of carbon monoxide and ozone from MOZAIC aircraft over Delhi,India during 2003–2005     

Partha S. Bhattacharjee  Ramesh P. Singh  Philippe Nédélec 《Meteorology and Atmospheric Physics》2015,127(2):229-240

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Impact of 4DVAR Assimilation of AIRS Total Column Ozone Observations on the Simulation of Hurricane Earl   总被引：1，自引：0，他引：1       下载免费PDF全文

LIU Yin  ZOU Xiaolei 《Acta Meteorologica Sinica》2015,29(2):257-271

The Atmospheric Infrared Sounder(AIRS) provides twice-daily global observations of brightness temperature, which can be used to retrieve the total column ozone with high spatial and temporal resolution.In order to apply the AIRS ozone data to numerical prediction of tropical cyclones, a four-dimensional variational(4DVAR) assimilation scheme on selected model levels is adopted and implemented in the mesoscale non-hydrostatic model MM5. Based on the correlation between total column ozone and potential vorticity(PV), the observation operator of each level is established and five levels with highest correlation coefficients are selected for the 4DVAR assimilation of the AIRS total column ozone observations. The results from the numerical experiments using the proposed assimilation scheme for Hurricane Earl show that the ozone data assimilation affects the PV distributions with more mesoscale information at high levels first and then influences those at middle and low levels through the so-called asymmetric penetration of PV anomalies.With the AIRS ozone data being assimilated, the warm core of Hurricane Earl is intensified, resulting in the improvement of other fields near the hurricane center. The track prediction is improved mainly due to adjustment of the steering flows in the assimilation experiment.  相似文献   

Satellite Data Assimilation of Upper-Level Sounding Channels in HWRF with Two Different Model Tops          下载免费PDF全文

ZOU Xiaolei  WENG Fuzhong  Vijay TALLAPRAGADA  LIN Lin  ZHANG Banglin  WU Chenfeng  QIN Zhengkun 《Acta Meteorologica Sinica》2015,29(1):1-27

The Advanced Microwave Sounding Unit-A(AMSU-A) onboard the NOAA satellites NOAA-18 and NOAA-19 and the European Organization for the Exploitation of Meteorological Satellites(EUMETSAT)Met Op-A, the hyperspectral Atmospheric Infrared Sounder(AIRS) onboard Aqua, the High resolution Infra Red Sounder(HIRS) onboard NOAA-19 and Met Op-A, and the Advanced Technology Microwave Sounder(ATMS) onboard Suomi National Polar-orbiting Partnership(NPP) satellite provide upper-level sounding channels in tropical cyclone environments. Assimilation of these upper-level sounding channels data in the Hurricane Weather Research and Forecasting(HWRF) system with two different model tops is investigated for the tropical storms Debby and Beryl and hurricanes Sandy and Isaac that occurred in 2012. It is shown that the HWRF system with a higher model top allows more upper-level microwave and infrared sounding channels data to be assimilated into HWRF due to a more accurate upper-level background profile. The track and intensity forecasts produced by the HWRF data assimilation and forecast system with a higher model top are more accurate than those with a lower model top.  相似文献   

Changes in the structures of mixed-layer illite-smectite during flooding of terrigenous oil reservoirs     

《Russian Geology and Geophysics》2014,55(7):915-928

A difference-spectrum method is proposed for the qualitative assessment of changes of illite-smectite structures accompanying the flooding of oil reservoirs. The method permits one to get an open system and reduce the application of procedures based on Markov’s chain formalism. A computer simulation is made to obtain spectra by subtracting the spectrum of an ethylene glycol-saturated sample from the spectrum of an air-dried preparation throughout the entire range of concentrations of illite and smectite components with a short-range order factor R = 0 or R = 3.It has been established that only in the presence of filtration are the maximum and minimum of the spectra in the range of 12.5-9.4 A complicated by a number of local extrema, whose position is specified by the structure of intermediate phases. The flooding process first involves mixed-layer phases with R = 0, leading to a partial segregation of the structures into phase with one and two networks of interlayer H₂O. When the secondary mica particles break, phases with R = 3 appear along the boundaries of nanoblocks, first only with 1 H₂O and then only with 2 H₂O in labile interspaces. Their coexistence with the phases R = 0 in the sample proves the existence of percolation effects due to two-phase filtration in the porous medium. The fully flooded reservoir is always dominated by a mechanical mixture of illite-smectite phases of different nature with R = 0 and with different ratios of components. Transformation of mica that can drastically reduce oil production begins long before the appearance of flooding zones, which are revealed by standard logging methods.  相似文献   

Evaluation of TRMM rainfall for soil moisture prediction in a subtropical climate   总被引：1，自引：1，他引：0  

Manika Gupta  Prashant K. Srivastava  Tanvir Islam  Asnor Muizan Bin Ishak 《Environmental Earth Sciences》2014,71(10):4421-4431

The Tropical Rainfall Measuring Mission (TRMM) is a joint space mission between NASA and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall. In this study, the daily rainfall from TRMM has been utilized to simulate the soil moisture content up to 30 cm vertical soil profile of at an interval depth of 15 cm by using the HYDRUS 1D numerical model for the three plots. The simulated soil moisture content using ground-based rainfall and TRMM-derived rainfall measurements indicate an agreeable goodness of fit between the both. The Nash–Sutcliffe efficiency using ground-based and TRMM-derived rainfall was found in the range of 0.90–0.68 and 0.70–0.40, respectively. The input data sensitivity analysis of precipitation combined with different irrigation treatment indicates a high dependency of soil moisture content with rainfall input. The overall analysis reveals that TRMM rainfall is promising for soil moisture prediction in absence of ground-based measurements of soil moisture.  相似文献   

博斯腾湖表层沉积物无机碳及其稳定同位素空间异质性   总被引：4，自引：2，他引：2  

于志同  王秀君  赵成义  兰海燕 《湖泊科学》2015,27(2):250-257

2012年8月,在新疆博斯腾湖13个站点进行表层沉积物采集,分析无机碳及其碳、氧稳定同位素的含量和空间分布特征,探讨该湖表层沉积物无机碳(TIC)的空间变化影响因素.结果表明:2012年,博斯腾湖表层沉积物TIC含量平均值为5.5%,变幅为3.8%~9.8%,而δ13Ccarb和δ18Ocarb平均值分别为0.71‰和-4.4‰,范围为-0.23‰~2.27‰和-5.53‰~-2.55‰.从空间来看,湖泊北岸TIC值明显高于南岸,最高值出现在湖泊西北部的黄水沟水域,而河口区和湖心区最低.总体上,博斯腾湖表层沉积物TIC主要是湖泊自生的,其空间分布主要受开都河、黄水沟等入湖河水的影响,导致水体矿化度和营养盐的空间差异,进而影响了碳酸盐的析出与沉淀.另外,湖泊局部的水动力条件也影响TIC的保存与分布.δ13Ccarb与δ18Ocarb的极显著正相关说明近几年博斯腾湖封闭程度较好,尤其是东部大湖区,属于封闭环境碳酸盐沉淀.  相似文献   

中国超大城市综合实验:京、沪、穗气溶胶理化和吸湿特性          下载免费PDF全文

李占清  王玉莹  吴昊  金筱艾  李尚泽  陈璐  任荣敏  张东梅  张芳 《大气科学学报》2023,46(3):441-452

气溶胶对环境、气象和人体健康都有较大影响,这些影响与气溶胶理化特性(粒子尺度谱、化学组分、混合状态等)密切相关。为了深入研究气溶胶的环境和气候效应,发展了一套气溶胶在线综合观测系统。本文介绍了利用该系统在北京、上海、广州三个超大城市开展的综合观测实验结果。通过对比分析发现,广州气溶胶数浓度最高,其粒子尺度谱分布特征与北京特征相似,均以核模态为主,上海气溶胶数浓度则整体较低。对比三个超大城市的新粒子生成(New Particle Formation,NPF)特征发现,北京NPF的发生频率低于广州,主要由于北京地区大气中大粒径气溶胶更多,较高的碰并汇抑制了NPF的发生和发展。研究发现,观测期间北京和上海站点气溶胶的吸湿性强于广州,人为一次性排放气溶胶吸湿性较弱。气溶胶吸湿性日变化特征与人为活动、气溶胶老化程度密切相关。此外,三个超大城市中气溶胶光吸收系数的日变化特征存在明显差别,北京站点的气溶胶吸收系数呈现白天高、夜间低的特点,而广州站点气溶胶的吸收系数呈现相反的日变化趋势,这可能是由观测站周边的环境差异及大气边界层的变化特征差异造成的。  相似文献   

GRAPES全球四维变分同化分析场质量的初步诊断分析          下载免费PDF全文

刘昕  陈静  朱跃建  陈法敬  马雅楠  王静 《气象科学》2021,41(6):804-817

为了深入认识全球四维变分同化系统(Global Regional Assimilation and Prediction System Four-Dimensional Variational, GRAPES 4DVAR)分析场质量,利用2019年3月1日至2020年2月29日GRAPES 4DVAR 7层等压面的高度、温度、纬向和经向风等4个要素的分析场及同期ERA5再分析场资料和探空观测资料,基于Pearson相关系数、偏差统计和EOF分解等多种统计分析方法,对GRAPES 4DVAR分析场质量进行了评估。结果表明:(1)GRAPES 4DVAR各要素分析场与ERA5再分析场具有显著的正相关(相关系数均通过α=0.01显著性水平检验),其中高度场和温度场的相关系数大于0.99,风场的相关系数大于0.85,GRAPES 4DVAR分析场和ERA5再分析场与探空观测的均方根偏差值的大小及分布相似,表明GRAPES 4DVAR同化分析场具有较高的质量,且北半球和南半球的分析质量优于热带地区;(2)GRAPES 4DVAR温度和风的分析场与ERA5再分析场在北半球和南半球的偏差存在较明显的季节变化和空间变化,表现为夏半年偏差小于冬半年,中层偏差小于低层和高层,且在对流层低层(高层),南半球(热带地区)的偏差大于北半球和热带地区(南半球);(3)不同要素分析偏差的特征显示,温度分析偏差主要出现在对流层低层,极大值区位于北极和南极地区,而风场分析偏差主要位于对流层中高层,极大值区主要分布于青藏高原、非洲大陆西部及北部、东太平洋及大西洋赤道附近区域。  相似文献   

CWRF对青藏高原气温和降水模拟效果的综合评估          下载免费PDF全文

徐蓉蓉  梁信忠  段明铿 《大气科学学报》2021,44(1):104-117

利用CWRF(Climate-Weather Research and Forecasting model)对中国区域气候的31 a多物理集合模拟试验,分析了该模式对青藏高原气温和降水的模拟效果及其对水平分辨率和物理过程参数化方案的敏感性.结果表明:1)CWRF降尺度全面改善了全球模式对高原气温和降水的模拟,使气温年循...  相似文献   

四种定量降水预报客观订正方法对比研究   总被引：1，自引：0，他引：1  

苏翔  袁慧玲  朱跃建 《气象学报》2021,79(1):132-149

基于2019年全年、不同季节、不同预报时效的欧洲中期天气预报中心模式的定量降水预报,检验评估了频率匹配、最优TS评分、最优百分位、概率匹配4种定量降水预报客观订正法的综合性能.利用理想模型研究了不同雨带位移偏差和干湿偏差情形下频率匹配法与最优TS评分的表现,并通过个例订正展示了4种定量降水预报订正法的基本特征.结果表明...  相似文献