中国L波段探空湿度观测资料的质量评估及偏差订正

L波段探空观测资料无论在天气预报还是数值预报中均为最基本和最重要的一类数据,而其湿度观测资料的质量对同化分析及降水预报有直接影响。通过用L波段探空湿度观测资料与不同类型的其他观测反演的湿度资料互校及与NCEP、GRAPES、EC等不同模式分析场为背景的湿度场比较,评估中国L波段探空湿度观测资料的质量状况,对探空湿度资料的质量有了新的认识,为更好地使用该资料提供依据。研究发现中国L波段探空湿度观测资料存在偏干的现象,特别是当背景场湿度大于60%时,观测湿度偏低更加明显。通过分析其偏差特征,找出了适合中国L波段探空湿度观测资料偏差特点的分段函数订正方法。个例试验表明,对探空湿度观测资料的偏差订正后,观测偏差明显减小,订正效果非常显著;模式降水强度预报能力有一定的提高。从连续试验检验的降水预报评分(TS)和预报偏差(Bias)看,中雨和暴雨的预报在探空湿度观测偏差订正后都表现出正效果。     

恒湿盐湿度发生器的研制

具有连续循环系统和恒温系统的恒湿盐湿度发生器,首次在国内研制成功。该文介绍了恒湿盐湿度发生器的工作原理、误差分析、检定过程和标定结果。     

Application of Partial Least Squares Regression in Multimodal Integrated Forecasting of Water Vapor and Surface Air Temperature

The use of a new multi model integration method of Partial Least Squares regression (PLS) can completely eliminate the multicollinearity features to improve multi model’s integrated forecasting results of the humidity and temperature. Based on the four centers’ ensemble forecast results, namely, the European Center for Medium-Range Weather Forecasts (ECMWF), Chinese Meteorological Administration (CMA), the Japan Meteorological Agency (JMA) and the UK Met Office (UKMO), we built a 2012 multi mode (25°~60°N, 60°~150°E) 24 ~168 hours forecast time (interval 24 hours) multi model for humidity and temperature and used the four methods, like ensemble average (BREM) for eliminating the deviation, a simple set of average (EMN), Super Ensemble (SUP) and Partial Least Squares regression (PLS) for ground temperature multi model integration. We used the Root-Mean-Square Error (RMSE) and anomaly correlation coefficient (cor) to determine the effect of more modes of integration and to predict a short course of cold. The two prediction results showed that the Partial Least Squares regression (PLS) was the best multi model integrated method, more superior than the other three single modes and compared with the other three methods, it showed better prediction performance, which has certain value and application prospect.     

高美古空气湿度的初步分析

给出丽江高美古天文候选点两年的湿度观测结果与宾川３００２ｍ山峰的比较,初步分析了湿度对天文可用时间及视宁度的影响。     

GPR survey to confirm the location of ancient structures under the Valencian Cathedral (Spain)

This paper describes the ground-penetrating radar (GPR) survey performed inside the Cathedral of Valencia, Spain. It is part of historical studies performed in the Cathedral in order to add information to old maps and documents in the Cathedral Archives and also to analyze the extent and importance of potentially destructive moisture areas that were appearing on the floor. The construction of the Cathedral of Valencia occurred in three stages, all of which are well-documented in the Cathedral Archives with detailed drawings, maps, and charts. The radar data were successful in locating crypts, ossuaries, sepulchers, and graves, and the location of ancient walls that existed before the final Cathedral expansion. Three cultural layers corresponding to the three periods of construction were also identified corresponding to the Roman, Arabian and Middle Age Epochs. Measurements of relative sub-floor moisture were obtained by comparing dielectric permittivity changes and radar velocity differences between materials in humid and non-humid areas.     

Characterization of electrical properties of organic-rich shales at nano/micro scales

A new experimental protocol is explored to characterize electrical properties of hydrocarbon-bearing mudrocks at nano/micro scales. Two current flow regimes of peak force - tunneling atomic force microscopy (PF-TUNA) have been used: (1) the vertical out-of-plane current regime with hundred micrometer diameter top electrodes obtains homogenized conductivity quantitatively, (2) the horizontal in-plane current regime was shown powerful to visualize the conductive paths (related to connectivity and tortuosity) for heterogeneous and anisotropic shales. Results show that the approach works well with one to two layers of adsorbed water (25–55% relative humidity) under low frequency (0.5–20 Hz) for shale rocks. Current maps with sub-nanometer resolution emphasize the dominant role of hydrated ions associated with the hydrophilic clay minerals in driving the dielectric response of shales, while conductivity of pyrite and kerogen cannot be neglected for mature organic-rich shale conductive network. The acquired I-V curves at microscale provide a reliable mean to evaluate homogenized conductivity of such multiscale multi-component heterogeneous material under controlled environmental conditions. The procedure discussed herein serves as a complement for fine grained rocks and minerals of ionic-electronic hybrid conductive mechanism under partially water saturation. These results can be used to develop accurate electrical models, specifically for shale rocks with heterogeneous and sophisticated microstructure. The methodology can be also extended to other micro- or meso-porous geomaterials such as cementitious and bituminous nanoporous media.     

Wake effects on turbulent transport in the convective boundary layer

The effect of the downstream propagation of a wake on the transport of momentum, energy and scalars (such as humidity) in the convective boundary layer (CBL) is studied using a direct numerical simulation. The incompressible Navier–Stokes and energy equations are integrated under neutral and unstable thermal stratification conditions in a rotating coordinate frame with the Ekman layer approximation. Wake effects are introduced by modifying the mean velocity field as an initial condition on a converged turbulent Ekman layer flow. With this initial velocity distribution, the governing equations are integrated in time to determine how turbulent transport in the CBL is affected by the wake. Through the use of Taylor’s hypothesis, temporal evolution of the flow field in a doubly periodic computational domain is transformed into a spatial evolution. The results clearly indicate an increase in the scalar flux at the surface for the neutrally stratified case. An increase in wall scalar and heat flux is also noted for the CBL under unstable stratification, though the effects are diminished given the enhanced buoyant mixing associated with the hot wall.     

塔中比湿变化特征

本文计算出塔中气象站2007年的比湿,结合其他气象要素分析了塔中比湿的变化特征。结果显示：本地区比湿的月平均日总量7月最大（155.5 g?kg-1）,1月最小（21.8 g?kg-1）,年平均值为72.4 g?kg-1。年振幅为86.3 g?kg-1,相对年振幅为66%。夏季约为冬季的5倍。日最大值和日最小值夏季大于冬季,其中7月最大,分别为263.4 g?kg-1和93.4 g?kg-1。夏季最高,冬季最低,秋季高于春季。四季的平均日变化7月最大,1月最小,4月与10月相差不大。4月与10月的日峰值相差0.1 g?kg-1,7月和1月的日峰值相差6.2 g?kg-1。各季晴天日变化较小。日总量最大值与最小值在夏季相差最大,冬季相差最小。逐日比湿上下变动的离散度在冬季最小,其次是春季和秋季,夏季最大,这与地方气候特征有关。降水天比湿增加,沙尘天比湿减小。各季比湿与气温、相对湿度的相关性较高,水汽压和露点温度也与比湿有很大的正相关性。     

多年冻土地区水泥稳定砂砾抗冻融耐久性模拟试验

通过控制试件湿度,模拟基层实际使用中的最不利湿度状况下的冻融循环试验,分析了冻融循环次数和试件湿度状况对混合料耐冻系数的影响.结果表明,耐冻系数随冻融循环次数的增加而不断减小,湿度对抗冻融耐久性评价结果有明显影响.多年冻土地区水泥稳定砂砾的抗冻融耐久性评价不宜直接采用水泥混凝土的饱水冻融试验方法,采用模拟基层的最不利湿度状况的冻融试验,以10次冻融循环时弯拉强度损失表示的耐冻系数作为指标,评价结果稳定,更符合实际使用情况.     

Assessment and Assimilation of FY-3 Humidity Sounders and Imager in the UK Met Office Global Model

China's Feng Yun 3(FY-3) polar orbiting satellites are set to become an important source of observational data for numerical weather prediction(NWP),atmospheric reanalyses,and climate monitoring studies over the next two decades.As part of the Climate Science for Service Partnership China(CSSP China) program,FY-3 B Microwave Humidity Sounder 1(MWHS-1) and FY-3 C MWHS-2 observations have been thoroughly assessed and prepared for operational assimilation.This represents the first time observations from China's polar orbiting satellites have been used in the UK's global NWP model.Since 2016,continuous data quality monitoring has shown occasional bias changes found to be correlated to changes in the energy supply scheme regulating the platform heating system and other transient anomalies.Nonetheless,MWHS-1 and MWHS-2 significantly contribute to the 24-h forecast error reduction by 0.3% and 0.6%,respectively,and the combination of both instruments is shown to improve the fit to the model background of independent sounders by up to 1%.The observations from the Microwave Radiation Imager(MWRI) also are a potentially significant source of benefits for NWP models,but a solar-dependent bias observed in the instrument half-orbits has prevented their assimilation.This paper presents the bases of a correction scheme developed at the Met Office for the purpose of a future assimilation of MWRI data.