利用GPS技术遥感北极黄河站可降水量的研究          下载免费PDF全文

张胜凯 赵云鄂栋臣  宁新国徐优伟 雷锦韬 《极地研究》2015,27(3):264-270

利用地基GPS的手段对北极黄河站可降水量进行了研究,分析了影响可降水量计算的三个因素:天顶总延迟、天顶干延迟和大气加权平均温度,验证了天顶总延迟和天顶干延迟的可靠性,得到了适合北极黄河站区的大气加权平均温度模型,并且将GPS可降水量与无线电探空的结果进行了比较,得到两者差值的标准差优于2 mm。  相似文献   

高空全月观测数据文件质控技术     

吴兴洋  潘徐燕  周处强  周成霞  柯利平 《气象科技》2015,43(1):43-48

简要介绍了高空全月观测数据文件生成及组成。讨论了L波段雷达观测系统数据处理软件处理高空气象探测资料的方法和现有高空气象观测资料,以及高空全月观测数据文件质检软件的质控功能,指出质控高空全月观测数据文件的关键是对高空观测基础数据文件（秒数据文件）的质控。秒数据文件是雷达接收信号的编码数据,必须综合应用高空全月观测数据文件质检软件与L波段雷达数据处理软件的各项功能,才能做好高空全月观测数据文件的质量控制。列举了几个典型示例,指出高空全月观测数据文件质检软件现用的参数库与实际观测资料相比较有缺陷。  相似文献   

探空气球漂移特征及对三角形法计算散度的影响   总被引：1，自引：1，他引：0       下载免费PDF全文

王学忠  胡邦辉  王举  黄泓  邹勋 《应用气象学报》2015,26(3):319-327

利用2006—2013年南京站、安庆站和杭州站探空资料,讨论华东地区探空气球的漂移特征。设计不考虑气球漂移、考虑全部气球漂移和考虑部分气球漂移3个试验,比较3种情况下三角形法计算的散度差异。结果表明:气球漂移主要受大气环流及其变化影响,纬向上7月和8月气球随高度增加,先向东漂移、后向西漂移,其他月份以向东漂移为主,冬季漂移距离大;经向上受季风影响明显。考虑全部和部分气球漂移与不考虑气球漂移的散度对比表明,平均绝对偏差各月在对流层顶附近均有极大值;相对偏差季节分布明显,前者在6—9月较大,极大值略大于7%,后者冬季大,1月在200 hPa达到25%,在50 hPa超过50%。因此,利用三角形法计算散度所在层次较高或所使用资料中传统探空和特种探空并存时,均需考虑气球漂移影响。  相似文献   

GNSS/MODIS信号紧耦合水汽层析算法     

张文渊  张书毕  郑南山  丁楠  刘鑫  马朋序 《测绘学报》2021,50(4):496-508

GNSS水汽层析技术凭借高精度、高时空分辨率及全天候监测等优点,已成为探测大气水汽最具潜力的技术之一。目前,融合多源大气遥感数据逐步成为弥补传统层析模型GNSS信号几何缺陷的研究热点。本文利用Terra卫星上的中分辨率成像光谱仪(moderate resolution imaging spectroradiometer,MODIS)提供的观测数据,首先分析了传统体素模型融合MODIS信号的不足;然后提出了基于体素节点模型的GNSS/MODIS信号紧耦合水汽层析算法,该算法将高分辨率MODIS PWV以三维信号的形式引入层析模型中;最后利用2016年7月徐州地区的15幅MODIS影像及同步GNSS数据对3种模型的层析结果质量进行了评估。试验结果表明:利用本文所提出的紧耦合算法,层析模型的平均有效观测信号数量提高了34.15%,层析结果平均RMSE(root mean square error)值降低了25.10%。此外,以邻近时刻探空站数据作为参考值,发现0~2 km的近地层,紧耦合算法的层析结果明显优于传统算法,这表明融合MODIS观测信号可改善近地层三维水汽场的重构质量。  相似文献   

基于第8届国际探空比对试验对GTS1 2型探空仪技术改进与对比分析     

郭启云  李伟  张玉存 《气象科技》2013,41(3):453-458

经过国内学者和WMO的评估,GTS1 2型探空仪需要进行技术改进以适应高空气象观测业务的发展需求。2012年,GTS1 2型探空仪在原体制基础上进行了技术改进(暂命名为GTS1 2A型)。2012年8月在阳江探空站开展比对试验,试验结果表明：GTS1 2A型探空仪夜间温度测量性能良好,系统误差在-03 ℃以内,标准偏差总体上在02 ℃左右;日间温度除探测中高层和出入云时外,系统误差整体上在-03 ℃,标准偏差整体上在04 ℃以内;气压除近地层有约-15 hPa的系统误差外,整体上系统误差和标准偏差小于GTS1 2型探空仪,尤其标准偏差在全量程范围内在07 hPa以内;GTS1 2A型探空仪湿度测量结果与RS92型探空仪一致性较好,灵敏度明显优于GTS1 2型探空仪,系统误差和标准偏差整体上均在10%RH以内。  相似文献   

Investigating the Dominant Source for the Generation of Gravity Waves during Indian Summer Monsoon Using Ground-based Measurements     

Debashis NATH  CHEN Wen 《大气科学进展》2013,30(1):153-166

Over the tropics,convection,wind shear(i.e.,vertical and horizontal shear of wind and/or geostrophic adjustment comprising spontaneous imbalance in jet streams) and topography are the major sources for the generation of gravity waves.During the summer monsoon season(June-August) over the Indian subcontinent,convection and wind shear coexist.To determine the dominant source of gravity waves during monsoon season,an experiment was conducted using mesosphere-stratosphere-troposphere(MST) radar situated at Gadanki(13.5 N,79.2 E),a tropical observatory in the southern part of the Indian subcontinent.MST radar was operated continuously for 72 h to capture high-frequency gravity waves.During this time,a radiosonde was released every 6 h in addition to the regular launch(once daily to study low-frequency gravity waves) throughout the season.These two data sets were utilized effectively to characterize the jet stream and the associated gravity waves.Data available from collocated instruments along with satellite-based brightness temperature(TBB) data were utilized to characterize the convection in and around Gadanki.Despite the presence of two major sources of gravity wave generation(i.e.,convection and wind shear) during the monsoon season,wind shear(both vertical shear and geostrophic adjustment) contributed the most to the generation of gravity waves on various scales.  相似文献   

Atmospheric River Signatures in Radiosonde Profiles and Reanalyses at the Dronning Maud Land Coast,East Antarctica     

Irina V.GORODETSKAYA  Tiago SILVA  Holger SCHMITHUSEN  Naohiko HIRASAWA 《大气科学进展》2020,37(5):455-476

Atmospheric rivers(ARs)are an important component of the hydrological cycle linking moisture sources in lower latitudes to the Antarctic surface mass balance.We investigate AR signatures in the atmospheric vertical profiles at the Dronning Maud Land coast,East Antarctica,using regular and extra radiosonde measurements conducted during the Year of Polar Prediction Special Observing Period November 2018 to February 2019.Prominent AR events affecting the locations of Neumayer and Syowa cause a strong increase in specific humidity extending through the mid-troposphere and a strong low-level jet(LLJ).At Neumayer,the peak in the moisture inversion(up to 4 g kg^?1)is observed between 800 and 900 hPa,while the LLJ(up to 32 m s^?1)is concentrated below 900 hPa.At Syowa the increase in humidity is less pronounced and peaks near the surface,while there is a substantial increase in wind speed(up to 40 m s?1)between 825 and 925 hPa.Moisture transport(MT)within the vertical profile during the ARs attains a maximum of 100 g kg?1 m s?1 at both locations,and is captured by both ERA-Interim and ERA5 reanalysis data at Neumayer,but is strongly underestimated at Syowa.Composites of the enhanced MT events during 2009?19 show that these events represent an extreme state of the lower-tropospheric profile compared to its median values with respect to temperature,humidity,wind speed and,consequently,MT.High temporal-and vertical-resolution radiosonde observations are important for understanding the contribution of these rare events to the total MT towards Antarctica and improving their representation in models.  相似文献   

FY-3C微波成像仪海上大气可降水产品质量检验     

吴琼  窦芳丽  郭杨  谷松岩 《气象》2020,46(1):73-79

中国自主研制的第二代极轨气象卫星的首颗业务星风云三号C星(FY-3C)于2013年9月23日发射升空。微波成像仪(MWRI)作为FY-3C上携带的重要微波载荷之一,能够实现对大气、海洋和陆地的全天时监测。其中,MWRI海上大气可降水量(TPW)产品在数值预报模式以及气候变化研究中具有很重要的应用价值,但是应用效果的好坏往往受产品精度的制约。使用长达4年的卫星观测资料,通过MWRI TPW业务产品和无线电探空及专用传感器微波成像仪(SSMIS) TPW业务产品的比较,对MWRI TPW产品(包括轨道产品、日产品和月产品)的质量进行检验。结果表明,轨道产品和地面实际观测的探空数据的平均相对误差在7%左右,均方根误差为2.6 mm;日产品和SSMIS日产品的均方根误差约为3 mm,和探空日产品的均方根误差小于2.1 mm;月产品和SSMIS月产品的均方根误差小于1.3mm。表明FY-3C MWRI TPW业务产品长期以来一直稳定运行且精度较高,具备实际应用潜力。  相似文献   

往返式探空观测资料的质量控制及不确定性分析     

王丹  王金成  田伟红  郭启云 《大气科学》2020,44(4):865-884

为了推动新型探测资料在数值预报模式中的应用,本文进行了往返式探空资料同化应用前重要的基础性研究工作。基于国内首次往返式探空观测资料,首先建立了面向业务化应用的往返式探空资料质量控制方案,通过对比和分析质量控制前后观测样本的统计特征,论证了质量控制方案的合理性,质量控制后探测要素抽样分布更为合理,要素间一致性得到提高。进而以数值天气预报高时间分辨率的模式预报场和同站址业务常规探空观测资料为参考,分析质量控制后资料的不确定性,结果表明往返探空探测精度达到了世界气象组织WMO（World Meteorological Center）规定的突破目标,部分探测要素甚至实现了理想目标,探测资料具有可用性。最后结合数值模式背景场探讨往返探空资料的可同化性,研究表明往返探空的风场观测和夜间温度观测满足变分同化系统的高斯、无偏假定,可直接同化;气压、湿度和日间温度观测在资料同化前需要开展偏差订正工作,从而更有效的发挥资料价值。本文的研究工作为今后往返探空资料在模式中的同化应用奠定了基础。  相似文献   

Four-dimensional variational data assimilation experiments for a heavy rain case during the 2002 IOP in China   总被引：3，自引：0，他引：3  

ZHANG Lin  NI Yunqi 《大气科学进展》2005,22(2):300-312

A heavy rainfall event along the mei-yu front during 22-23 June 2002 was chosen for this study. To assess the impact of the routine and additional IOP (intensive observation period) radiosonde observations on the mesoscale heavy rainfall forecast, a series of four-dimensional variational (4DVAR) data assimilation and model simulation experiments was conducted using nonhydrostatic mesoscale model MM5 and the MM5 4DVAR system. The effects of the intensive observations in the different areas on the heavy rainfall forecast were also investigated. The results showed that improvement of the forecast skill for mesoscale heavy rainfall intensity was possible from the assimilation of the IOP radiosonde observations. However,the impact of the IOP observations on the forecast of the rainfall pattern was not significant. Initial conditions obtained through the 4DVAR experiments with a 12-h assimilation window were capable of improving the 24-h forecast. The simulated results after the assimilation showed that it would be best to perform the intensive radiosonde observations in the upstream of the rainfall area and in the moisture passageway area at the same time. Initial conditions created by the 4DVAR led to the low-level moisture convergence over the rainfall area, enhanced frontogenesis and upward motion within the mei-yu front,and intensified middle- and high-level unstable stratification in front of the mei-yu front. Consequently,the heavy rainfall forecast was improved.  相似文献