A WRF(Weather Research and Forecasting Model)/CALMET(California Meteorological Model)coupled system is used to investigate the impact of physical representations in CALMET on simulations of the near-surface wind field...A WRF(Weather Research and Forecasting Model)/CALMET(California Meteorological Model)coupled system is used to investigate the impact of physical representations in CALMET on simulations of the near-surface wind field of Super Typhoon Meranti(2016).The coupled system is configured with a horizontal grid spacing of 3 km in WRF and 500 m in CALMET,respectively.The model performance of the coupled WRF/CALMET system is evaluated by comparing the results of simulations with observational data from 981 automatic surface stations in Fujian Province.The root mean square error(RMSE)of the wind speed at 10 m in all CALMET simulations is significantly less than the WRF simulation by 20%^30%,suggesting that the coupled WRF/CALMET system is capable of representing more realistic simulated wind speed than the mesoscale model only.The impacts of three physical representations including blocking effects,kinematic effects of terrain and slope flows in CALMET are examined in a specified local region called Shishe Mountain.The results show that before the typhoon landfall in Xiamen,a net downslope flow that is tangent to the terrain is generated in the west of Shishe Mountain due to blocking effects with magnitude exceeding 10 m/s.However,the blocking effects seem to take no effect in the strong wind area after typhoon landfall.Whether being affected by the typhoon strong wind or not,the slope flows move downslope at night and upslope in the daytime due to the diurnal variability of the local heat flux with magnitude smaller than 3 m/s.The kinematic effects of terrain,which are speculated to play a significant role in the typhoon strong wind area,can only be applied to atmospheric flows in stable conditions when the wind field is quasinondivergent.展开更多
Physical properties and geometrical morphologies of crushed air-cooled blast furnace slag （SCR） and crushed limestone （LCR） were comparatively investigated. The shape, angularity, surface texture and internal pore...Physical properties and geometrical morphologies of crushed air-cooled blast furnace slag （SCR） and crushed limestone （LCR） were comparatively investigated. The shape, angularity, surface texture and internal pore structure of aggregate particles for different size and gradation were numerically represented by sphericity （ψ） and shape index （SI）, angularity number （AN）, index of aggregate particle shape and texture （IAPST）, porosity and pore size, respectively. The results show that SCR is a porous and rough aggregate. Apparent density, void, water absorption and smashing index of SCR are obviously higher than those of LCR with the same gradation, respectively. However, bulk density of SCR is lower than that of LCR with the same gradation. SI, AN, IAPST and porosity of SCR are obviously higher than those of LCR with the same gradation, respectively. The smaller particle size of SCR, the larger of its AN, IAPST and porosity.展开更多
基金This research was supported by the National Basic Research Program of China(No.2015CB452806)the National Natural Science Foundation of China(Nos.41805088,41875080)+1 种基金Natural Science Foundation of Shanghai(No.18ZR1449100)Fundamental Research Foundation of Shanghai Typhoon Institute of the China Meteorological Administration(Nos.2018JB05,2019JB06).
文摘A WRF(Weather Research and Forecasting Model)/CALMET(California Meteorological Model)coupled system is used to investigate the impact of physical representations in CALMET on simulations of the near-surface wind field of Super Typhoon Meranti(2016).The coupled system is configured with a horizontal grid spacing of 3 km in WRF and 500 m in CALMET,respectively.The model performance of the coupled WRF/CALMET system is evaluated by comparing the results of simulations with observational data from 981 automatic surface stations in Fujian Province.The root mean square error(RMSE)of the wind speed at 10 m in all CALMET simulations is significantly less than the WRF simulation by 20%^30%,suggesting that the coupled WRF/CALMET system is capable of representing more realistic simulated wind speed than the mesoscale model only.The impacts of three physical representations including blocking effects,kinematic effects of terrain and slope flows in CALMET are examined in a specified local region called Shishe Mountain.The results show that before the typhoon landfall in Xiamen,a net downslope flow that is tangent to the terrain is generated in the west of Shishe Mountain due to blocking effects with magnitude exceeding 10 m/s.However,the blocking effects seem to take no effect in the strong wind area after typhoon landfall.Whether being affected by the typhoon strong wind or not,the slope flows move downslope at night and upslope in the daytime due to the diurnal variability of the local heat flux with magnitude smaller than 3 m/s.The kinematic effects of terrain,which are speculated to play a significant role in the typhoon strong wind area,can only be applied to atmospheric flows in stable conditions when the wind field is quasinondivergent.
基金Funded by the National Basic Research Program of China(No.2009CB623105)the Natural Science Foundation of Education Agency of Anhui Province(No.KJ2012A052)+1 种基金the Anhui Provincial Natural Science Foundation(No.1208085ME82)the Doctor Fund of Anhui University of Architecture(No.20123302)
文摘Physical properties and geometrical morphologies of crushed air-cooled blast furnace slag （SCR） and crushed limestone （LCR） were comparatively investigated. The shape, angularity, surface texture and internal pore structure of aggregate particles for different size and gradation were numerically represented by sphericity （ψ） and shape index （SI）, angularity number （AN）, index of aggregate particle shape and texture （IAPST）, porosity and pore size, respectively. The results show that SCR is a porous and rough aggregate. Apparent density, void, water absorption and smashing index of SCR are obviously higher than those of LCR with the same gradation, respectively. However, bulk density of SCR is lower than that of LCR with the same gradation. SI, AN, IAPST and porosity of SCR are obviously higher than those of LCR with the same gradation, respectively. The smaller particle size of SCR, the larger of its AN, IAPST and porosity.
