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1.
利用不同形状冰晶的散射特性,获得了非球形冰晶云的94/220 GHz测云雷达双波长比,探讨了非球形冰晶云的双波长比与云内微物理参数的关系,分析了衰减前后的星载雷达反射率因子及双波长比的垂直廓线。结果表明:（1）双波长比可以反映小到0.1 mm中值尺度的冰粒子,对粒子总数、谱的形状参数不敏感,对粒子大小、形状、云衰减较敏感。（2）雷达灵敏度一定时,星载雷达可测云厚与雷达波长、冰含水量（IWC）的垂直分布、云厚及衰减有关;没有进行衰减订正时,双波长比和衰减有关,冰含水量越大,波长越短,衰减越大,双波长比最大值与可探测云厚有关。两部雷达可探测冰含水量为0.001—0.1 g/m3、厚2 km的冰云;当云厚5 km、冰含水量垂直分布在0.001—0.2 g/m3时,云厚的94%基本可以被220 GHz云雷达探测到。（3）如果两部雷达气象方程中用水的介电因子,测量回波强度应进行介电因子的订正后再计算双波长比。 相似文献
2.
CloudSat卫星及其在天气和云观测分析中的应用 总被引：9，自引：0，他引：9
介绍了2006年4月28日成功发射的第1颗以对云层特性进行全球主动遥感测量CloudSat卫星的观测仪器、工作参数、运行方式、数据产品及“A—Train”卫星群等基本概况。CloudSat卫星主要有效载荷是94GHz（3mm波）云雷达,它可以“切开”云层,获得许多有关云的最新气象数据,主要数据产品包括了云的宏观物理参量和微观物理参量。介绍了CloudSat卫星已获得的典型天气和云的初期观测结果：从首次观测的云三维图片,可以清楚地看到南极洲上空风暴云的垂直剖面结构特征;从首张获得降雪云的垂直剖面图像可以得到降雪云层的发展状态以及结构特点;使用CloudSat统计数据可分析全球水凝物的分布特征。将TRMM卫星上的测雨雷达与CloudSat卫星上的云雷达联合观测研究,可以获得从薄云到浓厚云及降水的精细垂直结构特征。通过下载的CloudSat观测资料,对我国典型台风和层状云系等两类不同天气条件下云的宏微观结构特征等进行了初步分析,可以看到台风眼区附近云系的垂直结构随台风发展不同阶段的演变;从层状云系的垂直剖面可以清楚地发现云层的内部分层结构及不同相态的垂直分布特征等。 相似文献
3.
毫米波测云雷达系统及其外场试验结果初步分析 总被引：6，自引：1，他引：5
观测云宏观信息及其辐射特性的工具一直都很缺乏。利用毫米波测云雷达连续观测大气中的云能够获得有重要意义的参数,这些参数包括宏观上的云厚、云高、云层数,微观上云粒子的大小、滴谱分布、冰与液态水的含量等,它们不仅决定了云的上行、下行辐射的影响效果,也是研究自然降水过程的重要参数。文章介绍了2007年中国气象科学研究院研发的应用于探测云、雾和沙尘暴垂直结构的机动式8.6 mm毫米波雷达系统(HMBQ),重点介绍测云雷达在2008~2009年主要参加的外场试验情况,最后给出了探测得到的各种类型云(包括非降水云、弱降水云以及降雪云等)的雷达回波图,并作了初步分析。 相似文献
4.
在众多种针对云垂直结构的探测中,毫米波雷达可获取云底、云顶、云厚等完整的云垂直结构信息,并可以连续监测云的垂直剖面变化,是有力的探测手段之一。而无线电探空因其直接的测量优势,能直观、确切地描述大气湿度垂直结构,可将其进一步处理生成云垂直结构信息,并作为一种数据源用于与毫米波雷达云垂直结构探测结果进行比对,以评估毫米波雷达针对云宏观垂直结构的探测性能,为毫米波雷达更好地应用于云探测提供参考。通过获取位于北京南郊观象台的毫米波雷达2014年10月28日至2015年2月17日长达113天连续观测的反射率因子以及探空温、压、湿数据,设计或选取合适的方法对二者进行云边界的计算,并进行云高（包括云底高和云顶高）以及云层数的一致性比对分析。结果认为,除对于高层云的云顶高度毫米波雷达由于探测限制不能探测到10 km以上的云顶,某些时刻与探空产生较大差异外,在云底高度以及中低云的云顶高度上可以与探空观测取得很好的匹配效果,对于云的垂直分层上二者也有较强的一致性。该毫米波雷达具有较为准确并连续刻画10 km以下云垂直结构的能力。 相似文献
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星载毫米波测云雷达在研究冰雪天气形成的云物理机制方面的应用潜力 总被引：3，自引：2，他引：1
从2008年1月10日起,受强冷空气和暖湿气流共同影响,中国南方大部分地区遭遇1954年以来罕见的冰冻天气,此次天气过程持续时间长、冰冻范围广、受灾程度重.文中简要介绍了毫米波雷达的探测特点及衰减特性;重点利用CloudSat 卫星上搭载的3 mm波长云廓线毫米波雷达(CPR)的探测结果分析了1月28日、2月10日南方冰雪天气形成的云物理机制,并且与C波段测雨雷达探测结果对比;结果表明:(1)毫米波雷达具有高空间分辨率,能够清楚地反映云的垂直和水平结构,且清晰地反映云中0℃层融化带的垂直特征.(2)1月28日湖南冻雨、2月10日贵州冻雨分别是"冰雪-雨-过冷雨"和"过冷云-过冷雨"两种典型的云物理机制,云内0℃层融化带的强度和厚度与近地面温度的高低是能否形成冻雨天气的关键因素.(3)毫米波雷达在冰冻天气研究中有很大的应用潜力;充分将毫米波雷达与天气测雨甫达以及其他遥感手段结合,可以取长补短、相得益彰.发展毫米波探测技术将对研究各种天气形成的微观物理机制、云物理的发展、气候变化的研究及人工影响天气等工作均有重要意义. 相似文献
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风云三号降水测量雷达技术性能分析 总被引：1，自引：0，他引：1
风云三号降水测量卫星主要用于台风等灾害性天气系统强降水的监测,并提供全球中低纬度地区降水的结构信息。降水三维结构的准确测量是通过风云三号降水测量卫星的核心载荷——双频降水测量雷达实现的。首先介绍了风云三号降水测量雷达的主要任务与探测能力要求,然后通过仿真技术对降水测量雷达距离分辨率、水平分辨率、扫描角度、天线旁瓣电平、测量精度、波束匹配精度等主要技术性能指标进行了详细的分析。最后,利用于2010年开展的降水测量雷达样机航空校飞试验评估验证了降水测量雷达的各项功能和主要性能参数。结果表明,风云三号降水测量雷达整体降水探测性能与全球降水测量卫星的双频降水雷达相当。 相似文献
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TRMM星载测雨雷达和地基雷达反射率因子数据的三维融合 总被引：3，自引：1，他引：2
TRMM卫星上的测雨雷达(TRMMPR)探测资料分布均匀且具有很高的垂直分辨率,但灵敏度较低;地基雷达(GR)水平分辨率较高且具有较高的灵敏度,但其垂直分辨率低。通过将TRMM PR与GR反射率因子数据的三维数据融合,得到了更优的反射率因子图像。测雨雷达与地基雷达三维数据融合主要分为以下几步:测雨雷达与地基雷达数据预处理——如去杂波、衰减校正;测雨雷达与地基雷达时空匹配;选取和应用合适的三维图像融合算法;对融合后的图像进行效果评估。试验结果表明:融合后的图像不仅增大了信息量,更好地检测弱降水,还提高了空间三维(3D)分辨率,能更好地反映降水区域细节,且使得数据总体上具有更高的完整性和可靠性。此外,还将基于雷达资料估测的降水数据与地面雨量计数据进行对比,估计反射率因子数据融合在降水测量上的有效性。 相似文献
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《高原气象》2020,(3)
由于湍流、雷达探测灵敏度等对单波长云雷达探测回波强度谱密度的影响,造成了云雷达探测空气垂直运动速度和雨滴谱的误差,而双波长云雷达利用Mie散射造成的不同粒子后向散射大小差异来提高空气上升速度探测精度,从而提高反演雨滴谱的能力,并且可提高订正雨区衰减的能力。为此中国气象科学研究院研发了Ka/Ku双波段云雷达,并于2019年4月开始在广东龙门进行了云降水观测。本文针对该双波段云雷达观测模式和灵敏度等参数,在Gamma滴谱假设条件下,模拟分析了Ka、Ku波段功率谱及其比值与云降水参数、温度和湍流的关系,研究了雷达灵敏度、湍流对空气垂直速度、雨滴谱反演和衰减订正的影响,并利用个例数据进行了风场反演试验,讨论了双波段探测微降水动力和微物理参数的优势。结果表明:(1)温度只能影响两个波段功率谱比值(Ratio)的大小,对其峰值位置基本没有影响,而湍流对其峰值位置的影响不超过0.5 m·s~(-1);(2)湍流、雷达灵敏度对单波段云雷达探测空气垂直速度的影响比较明显,湍流使空气上升速度被高估,雷达最小可测回波强度随高度的增加而增加使该参数被低估,其影响远远大于温度和湍流对双波段云雷达反演空气垂直速度的影响;(3)对于单波段雷达来说,雷达灵敏度和湍流明显影响雨滴谱、含水量和衰减系数的探测,湍流使得雨滴谱拓宽,低估含水量和衰减系数;而雷达灵敏度却使反演的雨滴谱变窄,增加小粒子数浓度,并高估了含水量和衰减系数;(4)选取2019年4月15-16日的个例进行空气上升速度的反演,并与模拟分析的结果进行对比。结果显示实际观测数据反演的空气上升速度与模拟分析结果中的趋势较为一致。这项工作为单波段和双波段云雷达的多普勒功率谱数据分析和云降水微物理和动力参数的反演可提供参考。 相似文献
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为了揭示热带测雨卫星上的测雨雷达热带测雨卫星的星载雷达与X波段多普勒雷达在探测云的反射率因子的大小和结构方面的差异 ,用散射模式和数值模拟的方法讨论了这两种雷达的波长、雷达波入射方向、波瓣宽度等参量对反射率因子的大小和结构的影响 ,并利用所得结果讨论了两种雷达实际观测的差异。结果表明 :雷达波长和入射方向的不同引起的两种雷达测量的反射率因子的差异在 2 .0dBz以内 ,TRMMPR可在强回波中心探测到更大的反射率因子 ,并在很大程度上平滑了回波的结构 ,在强回波和弱回波区分别低估和高估 3～ 5dBz,造成了观测的云的面积增大、平均回波强度减小、面积积分降水量增大。这些理论结果还不能完全揭示两种雷达实际观测结果的差异 ,看来星载雷达和地基雷达探测结果的对比问题很复杂 ,其中雷达波的衰减问题是必须考虑的。 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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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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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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《大气和海洋科学快报》2013,(4):227
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. 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
18.
《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