基于准同雨团样本概念雷达和雨量计的实时同步结合方法

文中提出一种基于准同雨团样本概念雷达与雨量计(R&G)的实时同步结合技术。由于存在探测时空和分辨率的两种差异,雷达与雨量计(R&G)的同样本对应历来被视为一道难题。但观测表明,雨量计与其垂直上空雷达的小时累积量(ZOH,QG)存在符合幂律的相关性。以此为基础,提出旨在基本消除时空差异的准同雨团样本概念和5个R&G直接对应关系,着重研究一种简便实用的"时间积分垂直同步采样"TIVS,以及具有幂律形式的ZOH-QG关系。有意义的是在固定指数条件下系数AB或AM,具有Z-R转换和雨量计调整(订正)同步结合于一式的功能,两种设备在探测分辨率上巨大差异而引起的降水估算误差由此得到明显缓解。这种利用ZOH-QG关系估算地面小时降水累积量的方法称为RASIM。经过两个降水个例的试验初步表明,雷达估算半径为230km内地面区域小时累积降水量的正确率在90%以上,而全过程以站为计的点评估相对误差率平均为20%左右。本文还对时间积分垂直同步采样在具有风漂移效应各种环境风场中的可利用性作了详细分析,揭示了时间积分垂直同步采样方法的物理本质,明确指出这是一种近似的准同雨团样本采样;同时通过分析R&G数据对的分布规律,研究提出了有效的质量控制方法,明显改善了ZOH-QG关系的稳定性和合理性。

Spatial Variation and Sources of Atmospheric Sulfur Deposition in Nanchang

[Objective] The paper aimed to discuss the relationship between sulfur contents of mosses and the concentration of SO2-4 and the source of Atmospheric sulfur in Nanchang.[Method] 29 moss samples （Bryohaplocladium micriophyllum （Hedw.） R.Watanabe et Iwats） were collected from four sampling points,including North campus and Qianhu campus of Nanchang Power Station were determined.[Result] The results showed that sulfur contents of mosses tissues in North campus of Nanchang University （0.45±0.059%） were higher than Qianhu campus of Nanchang University （0.26±0.002%）,which coincided with the changing law of the concentration of SO2-4.Sulphur isotope of mosses tissues was-0.64‰-9.71‰.Sulphur isotope of mosses tissues in Meling （4.02‰-9.71‰） was higher than Qianhu campus of Nanchang University （0.55‰-0.56‰） and power plant （-0.64‰-0.45‰）.[Conclusion] Relationship between sulphur contents and sulphur isotopes of mosses tissues showed sulfur source of sulphur deposition in Nanchang city was mainly affected by 34S-enriched sulphur transported from northerly air masses and biogenic sulfur.

MODIS BRIGHTNESS TEMPERATURE DATA ASSIMILATION UNDER CLOUDY CONDITIONS Ⅱ: IMPACTS ON RAINSTORM FORECASTING

Satellite observations provide large amount of information of clouds and precipitation and play an important role in the forecast of heavy rainfall.However,we have not fully taken advantage of satellite observations in the data assimilation of numerical weather predictions,especially those in infrared channels. It is common to only assimilate radiances under clear-sky conditions since it is extremely difficult to simulate infrared transmittance in cloudy sky.On the basis of the Global and Regional Assimilation and Prediction Enhanced System 3-dimensional variance(GRAPES-3DVar),cloud liquid water content, ice-water content and cloud cover are employed as governing variables in the assimilation system.This scheme can improve the simulation of infrared transmittance by a fast radiative transfer model for TOVS (RTTOV)and adjust the atmospheric and cloud parameters based on infrared radiance observations.In this paper,we investigate a heavy rainfall over Guangdong province on May 26,2007,which is right after the onset of a South China Sea monsoon.In this case,channels of the Moderate Resolution Imaging Spectroradiometer(MODIS)for observing water vapor(Channel 27)and cloud top altitude(Channel 36)are selected for the assimilation.The process of heavy rainfall is simulated by the Weather Research and Forecasting(WRF)model.Our results show that the assimilated MODIS data can improve the distribution of water vapor and temperature in the first guess field and indirectly adjust the upper-level wind field.The tendency of adjustment agrees well with the satellite observations.The assimilation scheme has positive impacts on the short-range forecasting of rainstorm.

IMPACTS OF ATOVS DATA ASSIMILATION ON PREDICTION OF A RAINSTORM OVER SOUTHEAST CHINA

Using the Advanced Research WRF (ARW WRF) model and the Gridpoint Statistical Interpolation (GSI) three-dimensional variational analysis (3DVAR) system,the impact of assimilating ATOVS (Advanced TIROS Operational Vertical Sounder) radiance through the prototype Community Radiative Transfer Model (pCRTM) is evaluated on the forecasting of a heavy rainstorm occurring over the central Guangdong province in the southeast of China on 20-21 June 2005. A pair of comparison experiments (NODA and DA) for this case is conducted with multiple configurations,including nesting domains with 4-km and 12-km grid distances. The results showed that by changing the initial condition through data assimilation,a modified divergence and moisture field with the structure of dipoles has been added to the axis of the rainband with a southwest-northeast orientation. When more moisture carried by a southwesterly low level jet (LLJ) was converged into the northeast portion of the rainband around the observatory station of Longmen,the amplitude of moisture static energy (MSE) increased substantially at low levels much more than at middle levels,resulting in the enlarging of differences in MSE between 500 hPa and 850 hPa; the atmosphere became more unstable. Consequently,the convective rainfall increased in the northeast part of the province around the Longmen station,which was consistent with the observed distribution of rainfall.

Simultaneous Measurements of Rainfall Intensity, Low Energy Neutrons and Gamma Radiation in Sao Jose Dos Campos, SP, Brazil

The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of these parameters was carried out from end February to half of June 2013 just in Physics Department of ITA （Technological Institute of Aeronautics）. By correlating the data of measurements of intensity of X and ）,-radiations with the rainfall it has been found that this meteorological parameter had a significant influence on the background of these radiation profile. A possible reason for this fact is associated with the presence of radon gas in the environment that is dragged to the surface during the occurrences of local rainfall. In relation neutrons, it was possible to note that the rainfall has small influence on this parameter measures.

Big difference in ^87Sr/ ^86Sr ratios of basalt and basin water： higher ^87Sr/ ^86Sr ratios in plagioclase

We analyzed the ^(87)Sr/^(86)Sr ratios of basaltic rocks and basin water in Xuyi,China,and found a big difference,which may challenge conventional wisdom on the contribution of basalt weathering in end-member analysis.Results of an in-house weathering experiment suggest that rainwater and dust are not responsible for the difference.By isolating the major minerals in basalt,we found that plagioclase has much higher ^(87)Sr/^(86)Sr ratios than bulk basalt and basin water,which might explain the difference in ^(87)Sr/^(86)Sr ratios of basalt and basin water.We inferthatlow-temperaturehydrothermalalteration increased the ^(87)Sr/^(86)Sr ratios of plagioclase.Future analyses of end-member contribution in a mixed-rock basin should take into account that basin water and plagioclase have higher ^(87)Sr/^(86)Sr ratios than basaltic rocks.

新声

在国手“大揭秘”中,国乒队员对有关自己颜值问题的回答引起网友热议,在1-10分的自我颜值评分中,樊振东为自己打7分。他说:“我比及格好一点。”丁宁为自己打5分,朱雨玲为自己打1.5分.陈梦在采访记者的“利诱”下回答15分,刘高阳5分,同雨7分,顾玉婷5-6分,而林高远的回答是:不知道该给自己打几分。

Assimilating Doppler radar observations with an ensemble Kalman filter for convection-permitting prediction of convective development in a heavy rainfall event during the pre-summer rainy season of South China

This study examines the effectiveness of an ensemble Kalman filter based on the weather research and forecasting model to assimilate Doppler-radar radial-velocity observations for convection-permitting prediction of convection evolution in a high-impact heavy-rainfall event over coastal areas of South China during the pre-summer rainy season. An ensemble of 40 deterministic forecast experiments(40 DADF) with data assimilation(DA) is conducted, in which the DA starts at the same time but lasts for different time spans(up to 2 h) and with different time intervals of 6, 12, 24, and 30 min. The reference experiment is conducted without DA(NODA).To show more clearly the impact of radar DA on mesoscale convective system(MCS)forecasts, two sets of 60-member ensemble experiments(NODA EF and exp37 EF) are performed using the same 60-member perturbed-ensemble initial fields but with the radar DA being conducted every 6 min in the exp37 EF experiments from 0200 to0400 BST. It is found that the DA experiments generally improve the convection prediction. The 40 DADF experiments can forecast a heavy-rain-producing MCS over land and an MCS over the ocean with high probability, despite slight displacement errors. The exp37 EF improves the probability forecast of inland and offshore MCSs more than does NODA EF. Compared with the experiments using the longer DA time intervals, assimilating the radial-velocity observations at 6-min intervals tends to produce better forecasts. The experiment with the longest DA time span and shortest time interval shows the best performance.However, a shorter DA time interval(e.g., 12 min) or a longer DA time span does not always help. The experiment with the shortest DA time interval and maximum DA window shows the best performance, as it corrects errors in the simulated convection evolution over both the inland and offshore areas. An improved representation of the initial state leads to dynamic and thermodynamic conditions that are more conducive to earlier initiation of the inland MCS and longer maintenance of the offshore MCS.