The Infrared Atmospheric Sounding Interferometer (IASI) is a new-generation ultraspectral atmospheric sounding instrument mounted on the MetOp-A, the first operational polar-orbiting satellite developed by the Europea...The Infrared Atmospheric Sounding Interferometer (IASI) is a new-generation ultraspectral atmospheric sounding instrument mounted on the MetOp-A, the first operational polar-orbiting satellite developed by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). It is an ultrahigh spectral-resolution atmospheric detector which can detect atmospheric chemical composition, temperature, and humidity profiles with high accuracy and resolution. In the present study, through comparative analyses of the similarities and differences between the IASI and the radiosonde observation (RAOB) water vapor data, and between the IASI and the Aqua-AIRS water vapor retrievals, a detailed and systematic assessment of the credibility of the IASI water vapor retrievals over the plateau region was made. A comparison of the IASI retrievals with the AIRS retrievals and the RAOB measurements over the Tibetan Plateau revealed that the IASI retrieval data are reliable and can be used for conducting further studies.展开更多
In this study,the Dynamical-Statistical-Analog Ensemble Forecast model(DSAEF_LTP model)for landfalling tropical cyclone(LTC)precipitation was employed to simulate the precipitation of 10 LTCs that occurred over China ...In this study,the Dynamical-Statistical-Analog Ensemble Forecast model(DSAEF_LTP model)for landfalling tropical cyclone(LTC)precipitation was employed to simulate the precipitation of 10 LTCs that occurred over China in 2018.With similarity region scheme(SRS)parameter values added and TC intensity introduced to the generalized initial value(GIV),four groups of precipitation simulation experiments were designed to verify the forecasting ability of the improved model for more TC samples.Results show that the simulation ability of the DSAEF_LTP model can be optimized regardless of whether adding SRS values only,or introducing TC intensity into GIV,while the experiment with both the two improvements shows a more prominent advantage in simulating the heavier precipitation of LTCs.Compared with four NWP models(i.e.,ECMWF,GFS,GRAPES and SMS-WARMS),the overall forecasting performance of the DSAEF_LTP model achieves a better result in simulating precipitation at the thresholds over 250 mm and performs slightly better than NWP models at the thresholds over 100 mm.展开更多
The Dynamical-Statistical-Analog Ensemble Forecast model for landfalling tropical cyclones(TCs)precipitation(DSAEF_LTP)utilises an operational numerical weather prediction(NWP)model for the forecast track,while the pr...The Dynamical-Statistical-Analog Ensemble Forecast model for landfalling tropical cyclones(TCs)precipitation(DSAEF_LTP)utilises an operational numerical weather prediction(NWP)model for the forecast track,while the precipitation forecast is obtained by finding analog cyclones,and making a precipitation forecast from an ensemble of the analogs.This study addresses TCs that occurred from 2004 to 2019 in Southeast China with 47 TCs as training samples and 18 TCs for independent forecast experiments.Experiments use four model versions.The control experiment DSAEF_LTP_1 includes three factors including TC track,landfall season,and TC intensity to determine analogs.Versions DSAEF_LTP_2,DSAEF_LTP_3,and DSAEF_LTP_4 respectively integrate improved similarity region,improved ensemble method,and improvements in both parameters.Results show that the DSAEF_LTP model with new values of similarity region and ensemble method(DSAEF_LTP_4)performs best in the simulation experiment,while the DSAEF_LTP model with new values only of ensemble method(DSAEF_LTP_3)performs best in the forecast experiment.The reason for the difference between simulation(training sample)and forecast(independent sample)may be that the proportion of TC with typical tracks(southeast to northwest movement or landfall over Southeast China)has changed significantly between samples.Forecast performance is compared with that of three global dynamical models(ECMWF,GRAPES,and GFS)and a regional dynamical model(SMS-WARMS).The DSAEF_LTP model performs better than the dynamical models and tends to produce more false alarms in accumulated forecast precipitation above 250 mm and 100 mm.Compared with TCs without heavy precipitation or typical tracks,TCs with these characteristics are better forecasted by the DSAEF_LTP model.展开更多
目的基于实时直接分析-四极杆飞行时间质谱法(direct analysis in real time-quadrupole time-of-flight mass spectrometry,DART-QTOF-MS)结合非靶向代谢组学,快速分析青果槟榔与烟果槟榔代谢物差异。方法通过单因素实验,考察影响DART...目的基于实时直接分析-四极杆飞行时间质谱法(direct analysis in real time-quadrupole time-of-flight mass spectrometry,DART-QTOF-MS)结合非靶向代谢组学,快速分析青果槟榔与烟果槟榔代谢物差异。方法通过单因素实验,考察影响DART离子源电离效率的关键因素;结合QTOF-MS以TOFMS和信息依赖采集模式分别在正离子和负离子模式下获得质谱数据,采用多元统计学软件建立无监督和有监督的判别模型并筛选差异化合物。采用MarkerView 1.3.1、PeakView软件及在线数据库对差异化合物进行初步鉴定。结果在正负两种扫描模式下,DART离子源的最佳工作条件为:离子化温度500℃、样品传输速度0.2 mm/s。在此条件下发现两种食用槟榔化学成分存在差异,获得了25种差异化合物;烟果槟榔中有20种化合物的相对含量高于青果槟榔,有5种化合物的相对含量低于青果槟榔。结论本研究采用实时直接分析质谱技术,具有操作方便、分析速度快、准确度高和稳定性好的优点。同时,该研究从代谢组学角度初步揭示了青果槟榔与烟果槟榔代谢物的差异性,可为食用槟榔的加工工艺研究及品质提升提供参考依据。展开更多
文摘为了充分利用Dome A地区绝佳的视宁度条件,计划将南极望远镜安装在15m高的塔架上并使用轻质膜圆顶.研究了在塔架和膜圆顶作用下风载对望远镜观测环境的影响,利用计算流体力学(Computational Fluid Dynamics,CFD)分析了在10m·s^(-1)稳态风作用下,不同风向角、方位轴转动角以及镜筒转动角时,望远镜周围风速、湍动能的分布情况以及光程差的变化,同时研究了风屏对风速、湍动能的改善作用和带来的温升.结果表明,塔架和圆顶周围的风速与湍动能分布对风向的改变不敏感;迎风状态时望远镜附近的湍流分布与风速分布情况整体优于背风状态;当风速为10m·s^(-1)时,在距离风屏1m远、3m高的位置处风速降为来流风速的1/3至1/4,望远镜附近的平均温升值为0.044 K.
基金supported by the State Key Basic Research Development Program(Grant No.2012CB417204)the R&D Special Fund for Public Welfare Industry(Meteorology) by the Ministry of Finance and the Ministry of Science and Technology(Grant Nos.GYHY200806007,GYHY201006014,and GYHY201206039)the National Natural Science Foundation(Grant Nos.41175064,40875022,and 40633016)
文摘The Infrared Atmospheric Sounding Interferometer (IASI) is a new-generation ultraspectral atmospheric sounding instrument mounted on the MetOp-A, the first operational polar-orbiting satellite developed by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). It is an ultrahigh spectral-resolution atmospheric detector which can detect atmospheric chemical composition, temperature, and humidity profiles with high accuracy and resolution. In the present study, through comparative analyses of the similarities and differences between the IASI and the radiosonde observation (RAOB) water vapor data, and between the IASI and the Aqua-AIRS water vapor retrievals, a detailed and systematic assessment of the credibility of the IASI water vapor retrievals over the plateau region was made. A comparison of the IASI retrievals with the AIRS retrievals and the RAOB measurements over the Tibetan Plateau revealed that the IASI retrieval data are reliable and can be used for conducting further studies.
基金National Key R&D Program of China(2019YFC1510205)National Natural Science Foundation of China(41675042)。
文摘In this study,the Dynamical-Statistical-Analog Ensemble Forecast model(DSAEF_LTP model)for landfalling tropical cyclone(LTC)precipitation was employed to simulate the precipitation of 10 LTCs that occurred over China in 2018.With similarity region scheme(SRS)parameter values added and TC intensity introduced to the generalized initial value(GIV),four groups of precipitation simulation experiments were designed to verify the forecasting ability of the improved model for more TC samples.Results show that the simulation ability of the DSAEF_LTP model can be optimized regardless of whether adding SRS values only,or introducing TC intensity into GIV,while the experiment with both the two improvements shows a more prominent advantage in simulating the heavier precipitation of LTCs.Compared with four NWP models(i.e.,ECMWF,GFS,GRAPES and SMS-WARMS),the overall forecasting performance of the DSAEF_LTP model achieves a better result in simulating precipitation at the thresholds over 250 mm and performs slightly better than NWP models at the thresholds over 100 mm.
基金National Key R&D Program of China(2019YFC1510205)Hainan Provincial Key R&D Program of China(SQ2019KJHZ0028)National Natural Science Foundation of China(41675042)。
文摘The Dynamical-Statistical-Analog Ensemble Forecast model for landfalling tropical cyclones(TCs)precipitation(DSAEF_LTP)utilises an operational numerical weather prediction(NWP)model for the forecast track,while the precipitation forecast is obtained by finding analog cyclones,and making a precipitation forecast from an ensemble of the analogs.This study addresses TCs that occurred from 2004 to 2019 in Southeast China with 47 TCs as training samples and 18 TCs for independent forecast experiments.Experiments use four model versions.The control experiment DSAEF_LTP_1 includes three factors including TC track,landfall season,and TC intensity to determine analogs.Versions DSAEF_LTP_2,DSAEF_LTP_3,and DSAEF_LTP_4 respectively integrate improved similarity region,improved ensemble method,and improvements in both parameters.Results show that the DSAEF_LTP model with new values of similarity region and ensemble method(DSAEF_LTP_4)performs best in the simulation experiment,while the DSAEF_LTP model with new values only of ensemble method(DSAEF_LTP_3)performs best in the forecast experiment.The reason for the difference between simulation(training sample)and forecast(independent sample)may be that the proportion of TC with typical tracks(southeast to northwest movement or landfall over Southeast China)has changed significantly between samples.Forecast performance is compared with that of three global dynamical models(ECMWF,GRAPES,and GFS)and a regional dynamical model(SMS-WARMS).The DSAEF_LTP model performs better than the dynamical models and tends to produce more false alarms in accumulated forecast precipitation above 250 mm and 100 mm.Compared with TCs without heavy precipitation or typical tracks,TCs with these characteristics are better forecasted by the DSAEF_LTP model.
文摘目的基于实时直接分析-四极杆飞行时间质谱法(direct analysis in real time-quadrupole time-of-flight mass spectrometry,DART-QTOF-MS)结合非靶向代谢组学,快速分析青果槟榔与烟果槟榔代谢物差异。方法通过单因素实验,考察影响DART离子源电离效率的关键因素;结合QTOF-MS以TOFMS和信息依赖采集模式分别在正离子和负离子模式下获得质谱数据,采用多元统计学软件建立无监督和有监督的判别模型并筛选差异化合物。采用MarkerView 1.3.1、PeakView软件及在线数据库对差异化合物进行初步鉴定。结果在正负两种扫描模式下,DART离子源的最佳工作条件为:离子化温度500℃、样品传输速度0.2 mm/s。在此条件下发现两种食用槟榔化学成分存在差异,获得了25种差异化合物;烟果槟榔中有20种化合物的相对含量高于青果槟榔,有5种化合物的相对含量低于青果槟榔。结论本研究采用实时直接分析质谱技术,具有操作方便、分析速度快、准确度高和稳定性好的优点。同时,该研究从代谢组学角度初步揭示了青果槟榔与烟果槟榔代谢物的差异性,可为食用槟榔的加工工艺研究及品质提升提供参考依据。
