A severe storm that occurred over Beijing in northern China on 23 June 2011 was simulated with two different ice crystal parameterization schemes(the DeMott scheme and Meyers scheme) by using the Regional Atmospheric ...A severe storm that occurred over Beijing in northern China on 23 June 2011 was simulated with two different ice crystal parameterization schemes(the DeMott scheme and Meyers scheme) by using the Regional Atmospheric Modeling System. Compared with the DeMott scheme, the simulation results with the Meyers scheme have the following characteristics:(1) Updrafts are stronger and more numerous;(2) The cloud is better organized and contains a greater peak of ice-phase hydrometeor mixing ratios;(3) Cloud water and hail mixing ratios increase while graupel mixing ratios decrease;(4) The surface precipitation is initially greater. However, at the end of the simulation, less precipitation is produced. In short, the differences between the two schemes are not obvious, but the De Mott scheme has a relatively more reasonable result.展开更多
The scale factor accuracy of superconducting gravimeters （SG） can be largely improved by a high repetition rate of calibration experiments. At stations where the availability of absolute gravimeters is limited, care...The scale factor accuracy of superconducting gravimeters （SG） can be largely improved by a high repetition rate of calibration experiments. At stations where the availability of absolute gravimeters is limited, carefully calibrated spring gravimeters can be used for providing the reference signal assuming the irregular drift is properly adjusted. The temporal stability of the SG scale factor is assessable by comparing the temporal variations of M2 tidal parameters observed at neighboring SG sites or from synthetic tide models. Combining these methods reduces the SG scale factor error to a few 0.1%0. The paper addresses the particular procedure required for evaluating the calibration experiments based on spring gravimeters and presents results obtained at Conrad observatory （Austria）. Comparing the M2 amplitude factor modulation helped to reveal a SG scale factor offset of about 0.2%0 due to re-installation.展开更多
风是近地层大气的主要物理量,也是影响林火蔓延的重要因素。本文以2020年“3·30”西昌森林火灾周围的近地面风场为研究对象,基于中尺度数值模式(Weather Research and Forecasting,WRF),采用6种边界层方案进行敏感性实验。结果表明...风是近地层大气的主要物理量,也是影响林火蔓延的重要因素。本文以2020年“3·30”西昌森林火灾周围的近地面风场为研究对象,基于中尺度数值模式(Weather Research and Forecasting,WRF),采用6种边界层方案进行敏感性实验。结果表明,YSU和Shin-Hong方案对凉山10 m风速模拟误差最小,YSU和MYNN3方案对凉山10 m风向模拟误差最小;YSU和Shin-Hong方案能模拟出西昌火灾区风场分布以及风向转变;在西昌站点YSU方案模拟的边界层结构最接近观测值,能较好地表现边界层内动力和热力结构。展开更多
基金partially supported by the National Natural Science Foundation of China (Grant No. 41205099)the National Basic Research Program of China (973 Program, Grant Nos. 2014CB441403 and 2013CB430105)+1 种基金the Special Scientific Research Project of the Meteorological Public Welfare Profession of China (Grant No. GYHY201006031)the Guizhou Province Scientific Research Joint Project (Grant No. G[2013]4001)
文摘A severe storm that occurred over Beijing in northern China on 23 June 2011 was simulated with two different ice crystal parameterization schemes(the DeMott scheme and Meyers scheme) by using the Regional Atmospheric Modeling System. Compared with the DeMott scheme, the simulation results with the Meyers scheme have the following characteristics:(1) Updrafts are stronger and more numerous;(2) The cloud is better organized and contains a greater peak of ice-phase hydrometeor mixing ratios;(3) Cloud water and hail mixing ratios increase while graupel mixing ratios decrease;(4) The surface precipitation is initially greater. However, at the end of the simulation, less precipitation is produced. In short, the differences between the two schemes are not obvious, but the De Mott scheme has a relatively more reasonable result.
文摘The scale factor accuracy of superconducting gravimeters （SG） can be largely improved by a high repetition rate of calibration experiments. At stations where the availability of absolute gravimeters is limited, carefully calibrated spring gravimeters can be used for providing the reference signal assuming the irregular drift is properly adjusted. The temporal stability of the SG scale factor is assessable by comparing the temporal variations of M2 tidal parameters observed at neighboring SG sites or from synthetic tide models. Combining these methods reduces the SG scale factor error to a few 0.1%0. The paper addresses the particular procedure required for evaluating the calibration experiments based on spring gravimeters and presents results obtained at Conrad observatory （Austria）. Comparing the M2 amplitude factor modulation helped to reveal a SG scale factor offset of about 0.2%0 due to re-installation.
文摘风是近地层大气的主要物理量,也是影响林火蔓延的重要因素。本文以2020年“3·30”西昌森林火灾周围的近地面风场为研究对象,基于中尺度数值模式(Weather Research and Forecasting,WRF),采用6种边界层方案进行敏感性实验。结果表明,YSU和Shin-Hong方案对凉山10 m风速模拟误差最小,YSU和MYNN3方案对凉山10 m风向模拟误差最小;YSU和Shin-Hong方案能模拟出西昌火灾区风场分布以及风向转变;在西昌站点YSU方案模拟的边界层结构最接近观测值,能较好地表现边界层内动力和热力结构。
