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《广东气象》2018,(5)
利用费舍判别分析方法,将综合水汽含量(integrated water vapor,IWV)和液态水路径(liquid water path,LWP)作为预报因子,选取2016年36个降水样本和33个非降水样本,对降雨发生前120 min每10 min建立1个降水预报2级判别方程(共12个),并用2017年的样本进行检验,结果表明:(1)降水发生前2 h内,综合水汽含量(IWV)有明显波动,液态水路径(LWP)有明显增加,这些变化特征可作为判断降水临近的一个参考指标。(2)根据判别分析方法建立预报模型,发现随着距离降水时间越长,预报方程准确率越低,降水前10 min预报准确率最高,达83. 56%,降水前20、30、40 min次之,分别为73. 97%、63. 01%、58. 90%。(3)选取降水前20 min的预报方程,对其预报结果进行检验分析,并结合10、30 min的预报方程进行判断,发现预报降水时间比实况略偏早。实际应用时还可能出现短暂空报情况,因此还应结合预报因子增长趋势,剔除其他因素导致的波动。 相似文献
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三年地基微波辐射计观测温度廓线的精度分析 总被引：4，自引：2，他引：2
对安装在北京南郊观象台的地基微波辐射计测量的温度廓线数据的精度进行了分析。首先在2006年9月晴天条件下,对比由7个氧气通道测量的亮温与由微波辐射传输模式计算的亮温。得到51.250GHz的测量值与计算值的标准差值最大,为3.8K,其余通道均小于1.8K。2种亮温的偏差值以及绝对偏差值,在51.250和52.280GHz处大于1.0K,在其余5个通道处都小于1.0K。2种亮温拟合直线的斜率,在52.280和53.850GHz处分别为0.66与0.7,其余通道都大于0.8。然后,使用2005年9月—2008年8月的观测数据,对比地基微波辐射计与探空同时观测的大气温度。结果显示,2种测量技术的差异随高度而增大。另外,将3a观测数据按照季节以及晴天与非晴无降水天进行对比分析。结果显示,不同季节2种测量技术存在不同差异。其中,夏季测量差异最小。而晴天测量差异在3.250km以下比非晴无降水天小。 相似文献
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中亚地区常规气象观测稀疏，同化极轨卫星FY-3C上的微波湿度探测器-Ⅱ(MWHS-Ⅱ)辐射率资料可有效减小该地区数值预报初始场的不确定性。本研究首次在中亚快速更新多尺度资料分析和预报系统RMAPS-CA中同化了FY-3C/MWHS-Ⅱ辐射率，评估了其同化效果。研究发现：（1）单个时次冷启动的同化时间窗口内，仅约有56%的辐射率资料通过了质量控制并被RMAPS-CA同化。（2）偏差订正整体减小了各水汽通道的背景场辐射亮温偏差，最大减幅出现在通道14，达0.5 K。通道14偏差订正前的观测辐射亮温和背景场辐射亮温间存在较大偏差，是其同化应用中需要特别注意的。（3）FY-3C/MWHS-Ⅱ辐射率同化整体提高了RMAPS-CA系统对高空温度、位势高度、高空风速等的中短期预报准确率。同时，使得2米温度和10米风速的预报准确率预报均方根误差分别平均减小了0.2 K和2 m/s。其同化有效降低了小雨预报的漏报率和空报率，小雨预报的TS评分提升了16%。降低了中雨和大雨预报的漏报率，三个量级降水预报的BIAS评分分别提升了18%、38%和36%。 相似文献
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星载降水雷达机载校飞试验：地基多通道微波辐射计估算雷达路径积分衰减 总被引：1，自引：1，他引：0
介绍了在雷达观测降水试验中如何配合利用地基微波辐射计估算雷达路径积分衰减(PIA)的一种方法.所用的GPS高空探空资料和地基多通道微波辐射计的观测资料,均为中国首次星载降水雷达机载校飞试验中获得的数据.由于常规探空资料中没有云水含量的直接信息,因此,通过绝热液态水含量分析方法,从GPS探空数据中计算得到这些云参数值.用MWMOD进行亮温模拟并计算液态水含量.在晴空条件下,用该模式模拟了地基多通道微波辐射计12个通道的下行辐射亮温.通过设置相对湿度阈值,利用MWMOD模式自带的绝热液态水含量分析方法,从探空廓线中分析出液态水廓线,进而模拟出有云情况下的下行辐射亮温.辐射传输模式的模拟亮温和地基多通道微波辐射计观测亮温的对比表明,进行云分析之后的模拟亮温值更接近于实测值.由此,利用由辐射传输模式和地基微波辐射计,从探空廓线中分析出液态水廓线,计算出有云情况下的大气整层透过率,进而得到路径积分衰减,为降水雷达衰减订正提供一种有效手段. 相似文献
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通过冰雹云模式模拟的一次冰雹云降水过程中降水粒子廓线和微波辐射传输模式结合,分析了冰雹云发展的不同阶段的微物理含量垂直结构变化及其对微波亮温的影响,得到以下几点结论:1)如果微波通道受到降水粒子散射和辐射的共同作用,如降水云早期的85 GHz亮温,成熟期的19 GHz亮温及消散期的37 GHz亮温,由于辐射和散射信息互相抵消,致使亮温随雨强的变化较复杂,这些通道亮温和雨强的相关性明显降低,不宜被用来反演地面雨强。2)根据19 GHz亮温随地面雨强或冰相粒子柱含量的改变,可以大致确定降雨云的不同阶段:在发展阶段,主要是降雨层以上的冰相粒子,尤其霰粒影响19 GHz亮温,致使其亮温与冰相粒子柱含量具有较好的负相关,而与地面雨强相关性较差;在成熟阶段,主要受雨水上层逐渐增加的辐射和冰相粒子散射共同作用,使得19GHz亮温与地面雨强和冰相粒子柱含量的相关性都不太好;在消散阶段,19 GHz亮温主要受较强的雨水辐射影响,与地面雨强和冰相粒子柱含量均有着较高的正相关。3)37 GHz是相对比较稳定的通道,其亮温与地面雨强有较好的线性关系,尤其与冰相粒子柱含量相关性更好,因此是反演地面雨强和冰相粒子柱含量的最佳通道。85 GHz亮温对降雨云体的中高层结构较为敏感,使得其亮温随地面雨强增加而降低的变化比较离散,不如37 GHz的集中。 相似文献
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FY-3A微波探测资料的直接同化应用及云雨条件下的亮温模拟 总被引：1，自引：0，他引：1
针对FY-3A星载微波垂直探测的同化应用,在扩展WRF3Dvar中FY-3A微波资料同化功能和快速辐射传输模式RTTOV微波云雨粒子散射RTTOV-SCATT模块接口的基础上,以2008年“凤凰”台风为研究对象,试验了FY-3A晴空条件下微波资料同化应用对数值预报的影响,并以此为控制试验,进一步讨论云检测方案和偏差订正调整对资料应用效果的作用。在WRF3Dvar同一框架下,使用RTTOV和CRTM云雨散射模块对云雨条件下FY-3A微波亮温进行模拟,分析云雨辐射效应对FY-3A微波温度和湿度传感器观测模拟的影响,并比较两个快速辐射传输模式结果间的异同。结果表明:本个例中FY-3A微波资料的使用对台风强度预报误差的减小比路径预报更为明显。云检测是影响卫星资料效能发挥的关键因素之一,3.0和5.0分别是MWTS和MWHS使用单窗区通道作为云检测时的合适阀值。使用FY-3A资料导出的偏差订正系数可以改善偏差订正结果,并提高预报准确率。此外,对于MWTS,通道1是受云雨粒子辐射效应影响最显著的通道,通道2同样具有明显影响。MWHS全部5个探测通道均受云雨粒子辐射效应影响,云雨条件下通道1、2的模拟偏差最大。RTTOV和CRTM的结果具有相同的统计特征,但CRTM云雨粒子辐射效应带来的偏差比RTTOV要大。 相似文献
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提供高时间分辨率大气温度湿度廓线的地基微波辐射计近年来广泛使用,多通道观测亮温的数据质量是大气廓线产品合理性的基本保障。一般定期液氮绝对定标可以更好维护亮温数据质量,但实际操作颇为不易。辐射传输模式作为一种辅助工具,可以检验和认识地基微波辐射计观测亮温的数据质量。本文针对三个辐射传输模式:MonoRTM、ARTS和MWRT,结合北京探空观测资料、北京观象台和河北香河站同类型的德国RPG地基微波辐射计观测资料,分析比较了三个模式的模拟与观测亮温差异,评估不同辐射传输模式对地基微波辐射计观测的模拟能力。地基微波辐射计14个通道观测亮温与模式模拟的差异统计比较发现:三个模式的模拟结果与地基微波辐射计大部分通道的观测亮温都很接近,与观测结果具有很好一致性（如相关系数高达0.99）,而对温度通道ch8（51.26 GHz）和ch9（52.28 GHz）,三个模式模拟与观测相关系数明显较低（<0.80）,并且存在显著的绝对偏差（4～5 K）,表明模式在这两个通道的模拟能力有待提高。三个模式中,MonoRTM模式在温度通道ch8、ch9和ch10（53.86 GHz）存在明显的系统性偏差,尤其是ch8高达5 K;ARTS模式对水汽通道ch1（22.24 GHz）的模拟能力相对较弱;MWRT模拟与观测亮温在多个通道上相对更为接近和稳定,尤其系统性偏差最小。此外,探空廓线与地基观测站的空间位置不一致,对地基微波辐射计水汽通道的模拟结果影响较为显著,而对水汽不敏感的温度通道影响甚微。两地观测亮温与模式模拟的比对,初步表明北京观象台地基微波辐射水汽通道的观测质量有待改进。 相似文献
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结合MM5模式和三维微波辐射传输模式, 对2003年7月9日宜昌地区一次典型的中尺度降水中心的对流性降水云微波辐射特性进行研究。结果表明:MM5模式模拟的降水量和落区与实况一致,模拟的水凝物廓线也与TMI反演值接近,85.5 GHz通道辐射亮温与TMI实测情况相近。85.5 GHz通道亮温与地面雨强相关性很弱, 受云中云冰和雪花的散射降温作用显著, 由于其他粒子的综合作用以及斜角观测造成的位置偏移, 霰粒子对该通道亮温散射作用不明显。19.35 GHz通道亮温随雨强增加先升温后降温; 与霰粒子含量表现出明显的负相关关系。37.0 GHz通道亮温随雨强的增加而降温, 雨强大于20 mm/h后达到饱和, 主要受雨水降温作用影响。倾斜观测比天顶垂直观测产生更低的亮温低值中心, 且频率越高, 低值中心的偏移越严重。 相似文献
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TRMM卫星对一次冰雹降水过程的观测分析研究 总被引：7，自引：2，他引：7
利用TRMM卫星上时空匹配较好的测雨雷达(PR)、微波成像仪(TMI)、可见光和红外扫描仪(VIRS)观测资料,研究了1999年5月9日发生在黄淮地区的一次冰雹降水过程。根据卫星接连3个轨道的观测,综合分析了此次强对流降水过程在不同阶段的降水结构、云顶亮温和降雨厚度以及相应的微波亮温变化特征。观测分析表明,此次降水过程由对流很强的冰雹降水逐渐演变到对流渐弱的暴雨降水。冰雹降水阶段,云中有多个强对流单体,云体中高层有大量的固态降水粒子,使得中高层降水量在降水柱含量中贡献远大于融化层降水量的贡献;暴雨降水阶段,若干对流单体被大面积的层云降水包围,降水高度逐渐降低,云体中高层降水量明显减少,融化层降水量对柱含量的贡献明显增加。降水率廓线中不同高度的降水量对降水柱含量贡献的比较表明:中高层降水量占的比例越大,降雨云对流越强,反之,融化层降水量占的比例越大,降雨云越趋向为稳定的层云。微波亮温信号在不同降雨阶段随雨强的响应程度大不相同,这表明在反演地面降雨时,最好结合降雨云的结构特征及其发展阶段,针对不同降雨类型选取最为有效的微波通道组合来建立最佳反演模式。 相似文献
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The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics. 相似文献
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Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d. 相似文献
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Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region. 相似文献
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Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms. 相似文献
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Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on 相似文献
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《大气和海洋科学快报》2014,7(6):F0003-F0003
AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
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《大气和海洋科学快报》2014,(5):F0003-F0003
AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
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《大气科学进展》2014,(6)
正Aims Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome. 相似文献
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DING Yihui WU Guoxiong Da-Lin ZHANG ZHANG Renhe Co-Chief Editors 《Acta Meteorologica Sinica》2014,28(5):669-670
As we will soon celebrate the 90th anniversary of the founding of the Chinese Meteorological Society （CMS）,Acta Meteorologica Sinica （AMS）,which was originally named as Bulletin of the Chinese Meteorological Society,has gone through 89 years of development and excitement since her first issue in July 1925.According to archived documents （CMS Editorial Committee,1925）,AMS was founded to report the research findings of Chinese meteorologists,record their recommendations for improving meteorological services,and share their common meteorological interests in order to promote the growth of AMS such that more members could be inspired to conduct atmospheric research and meteorological knowledge would be better disseminated to and benefit the general public.By upholding and carrying forward this purpose,AMS has published many highly valuable scientific papers.Some could be treated as classical articles,which have produced important influences on both domestic and international meteorological communities and the related fields. 相似文献