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   

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   

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   

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   

Intercomparison of Humidity and Temperature Sensors: GTS1, Vaisala RS80, and CFH   总被引：8，自引：0，他引：8  

BIAN Jianchun  CHEN Hongbin  Holger VOMEL  DUAN Yunjun  XUAN Yuejian  LU Daren 《大气科学进展》2011,28(1):139-146

GTS1 digital radiosonde, developed by the Shanghai Changwang Meteorological Science and Technology Company in 1998, is now widely used in operational radiosonde stations in China. A preliminary comparison of simultaneous humidity measurements by the GTS1 radiosonde, the Vaisala RS80 radiosonde, and the Cryogenic Frostpoint Hygrometer (CFH), launched at Kunming in August 2009, reveals a large dry bias produced by the GTS1 humidity sensor. The average relative dry bias is in the order of 10% below 500 hPa, increasing rapidly to 30% above 500 hPa, and up to 55% at 310 hPa. A much larger dry bias is observed in the daytime, and this daytime effect increases with altitude. The GTS1 radiosonde fails to respond to humidity changes in the upper troposphere, and sometimes even in the middle troposphere. The failure of GTS1 in the middle and upper troposphere will result in significant artificial humidity shifts in radiosonde climate records at stations in China where a transition from mechanical to digital radiosondes has occurred. A comparison of simultaneous temperature observations by the GTS1 radiosonde and the Vaisala RS80 radiosonde suggests that these two radiosondes provide highly reproducible temperature measurements in the troposphere, but produce opposite biases for daytime and nighttime measurements in the stratosphere. In the stratosphere, the GTS1 shows a warm bias (<0.5 K) in the daytime and a relatively large cool bias (-0.2 K to -1.6 K) at nighttime.  相似文献   

我国飞机观测气温和常规高空观测气温的对比分析          下载免费PDF全文

廖捷  任芝花 《气象》2011,37(3):263-269

对2006年1月至2009年12月的飞机观测气温资料进行了质量控制,在此基础上通过其和常规高空气温资料的对比分析对飞机观测气温的可用性进行了评估.我国绝大部分飞机观测资料由B737-800和B737-700型飞机观测而得.统计结果表明:两种型号飞机的观测气温和常规高空观测气温的差值分布存在一定差异;差值呈准对称分布,64%的差值分布在-1℃至1℃;不同高度层上的差值不同.相对于常规高空观测气温,飞机观测气温值在700 hPa及以下偏低,在500 hPa及以上偏高.飞机观测气温和常规高空观测气温的差值大小和飞机型号及飞行状态有关.以北京地区的资料为例,利用北京首都机场上空飞机观测气温统计得到的月值和北京探空站常规高空观测气温月值没有显著性差异,各层次、时次的月值差异基本维持在-1℃至0.5℃之间.  相似文献   

国产珠状温度传感器对比分析     

李伟 《南京气象学院学报》2011,(4):346-353

通过比对试验,采取同球比对施放方式,选择德国GRAW探空仪作为比对标准,使用总共12次同球比对数据,对中国长峰、华云和大桥3种型号探空仪的珠状电阻温度传感器开展比对分析.经典型个例分析与统计分析表明:3个型号国产探空仪高空温度廓线与德国GRAW探空仪具有较好的整体一致性,温度测量夜间性能均好于白天;长峰探空仪温度探测性能随高度变化比较稳定,而华云探空仪与大桥探空仪性能相仿,均随高度性能下降,尤其是30km以上高空;长峰探空仪温度探测整体性能最好,相对系统误差在0.2℃左右;而华云探空仪与大桥探空仪误差可达1℃,且均表现为整体上温度测值偏低.体积较小的珠状温度传感器将是未来高空温度探测的一个好的选择,下一步需要改善华云探空仪与大桥探空仪温度传感器表面涂层工艺,两者的温度辐射订正算法也需要进一步完善.  相似文献   

用初估场对比中芬探空仪温度和位势高度记录   总被引：4，自引：3，他引：1       下载免费PDF全文

马颖  姚雯  黄炳勋 《应用气象学报》2011,22(3):336-345

对部分高空台站2007—2009年近3年探空记录的统计分析表明:邻近测站同一型号探空仪的温度和位势高度记录与6 h数值预报初估场的平均偏差一致,但不同型号探空仪记录与初估场的平均偏差存在明显差异,因此可以利用初估场进行邻近测站不同型号探空仪之间的间接对比。该文利用初估场与台站探空记录的差值,分析了使用芬兰Vaisala公司RS92型探空仪的中国香港站与邻近的使用L波段探空仪的梧州、汕头、东源、阳江4站2年的温度和位势高度记录的系统差,结果表明:19:00(北京时,下同),L波段探空仪的温度和位势高度记录在平流层分别偏低达1℃和30 gpm;07:00,L波段探空仪的温度记录在对流层偏高0.4℃,导致其位势高度记录也在对流层偏高;两套设备的系统差不仅有显著的日夜差异和季节性差异,也存在一定的年际差异。  相似文献   

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