为研究中国气象局(China Meteorological Administration,CMA)研发的中国第一代全球再分析产品CRA(CMA Global Reanalysis)对海雾模拟的适用性,将CRA与欧洲中心再分析产品ERA5(the 5th Generation of ECMWF Reanalysis)以及美国国家环...为研究中国气象局(China Meteorological Administration,CMA)研发的中国第一代全球再分析产品CRA(CMA Global Reanalysis)对海雾模拟的适用性,将CRA与欧洲中心再分析产品ERA5(the 5th Generation of ECMWF Reanalysis)以及美国国家环境预报中心的再分析产品FNL(Final Reanalysis Data)分别作为WRF(Weather Research and Forecast)模式驱动的初边界条件,对发生在琼州海峡的一次持续性海雾过程进行数值模拟。结果表明:将3种再分析产品作为初始场均能模拟出琼州海峡海雾发展过程。CRA和ERA5模拟的海雾在偏东风下开始发展,风向转为东北风后消散。CRA模拟的海雾强度最强且维持时间最长,FNL模拟的底层风场较早转为东北风,海雾消散早。在垂直方向上,ERA5和CRA模拟的海雾发展高度与实况接近,FNL则明显偏低。CRA中较低的逆温层以及近地层温度将水汽聚集在低层,使得海雾可以持续发展并长时间维持。在加入实时更新的高分辨率海温后,模拟的气海温差场更精细,可反映出琼州海峡中部及东部气海温差小于0.5℃的区域,模拟海雾发展的能力更强。展开更多
Sea spray,which comprises amounts of small ocean droplets,plays a significant role in the air-sea coupling,atmospheric and oceanic dynamics,and climate.However,it remains arduous to arrive at estimates for the efficie...Sea spray,which comprises amounts of small ocean droplets,plays a significant role in the air-sea coupling,atmospheric and oceanic dynamics,and climate.However,it remains arduous to arrive at estimates for the efficiency and accuracy of the sea spray induced air-sea heat and salt fluxes.This is because the microphysical process of sea spray evolution in the air is of extreme complexity.In this study,we iteratively calculated the sea spray induced air-sea heat and salt fluxes at various weather condition.To do so,we implemented one novel wave-steepness-dependent sea spray model into a bulk air-sea fluxes algorithm and utilized other sea spray models as comparisons.Based on the improved wave-dependent bulk turbulent algorithm,we observed that despite the negative contribution of sea spray to the sensible heat fluxes,the sea spray positively contributes to the air-sea latent heat fluxes,leading to an overall increase in the total air-sea heat fluxes.The additional heat fluxes caused by sea spray may be the missing critical process that can clarify the discrepancies observed between measured and modelled Tropical Cyclone’s development and intensification.In addition to heat fluxes,we observed that sea spray has significant impacts on the air-sea salt fluxes.As the sea salt particles are one of the main sources of the atmosphere aerosol,our results imply that sea spray could impact global and regional climate.Thus,given the significance of sea spray on the air-sea boundary layer,sea spray effects need to be considered in studies of air-sea interaction,dynamics of atmosphere and ocean.展开更多
Sea fog is a disastrous weather phenomenon,posing a risk to the safety of maritime transportation.Dense sea fogs reduce visibility at sea and have frequently caused ship collisions.This study used a geographically wei...Sea fog is a disastrous weather phenomenon,posing a risk to the safety of maritime transportation.Dense sea fogs reduce visibility at sea and have frequently caused ship collisions.This study used a geographically weighted regression(GWR)model to explore the spatial non-stationarity of near-miss collision risk,as detected by a vessel conflict ranking operator(VCRO)model from automatic identification system(AIS)data under the influence of sea fog in the Bohai Sea.Sea fog was identified by a machine learning method that was derived from Himawari-8 satellite data.The spatial distributions of near-miss collision risk,sea fog,and the parameters of GWR were mapped.The results showed that sea fog and near-miss collision risk have specific spatial distribution patterns in the Bohai Sea,in which near-miss collision risk in the fog season is significantly higher than that outside the fog season,especially in the northeast(the sea area near Yingkou Port and Bayuquan Port)and the southeast(the sea area near Yantai Port).GWR outputs further indicated a significant correlation between near-miss collision risk and sea fog in fog season,with higher R-squared(0.890 in fog season,2018),than outside the fog season(0.723 in non-fog season,2018).GWR results revealed spatial non-stationarity in the relationships between-near miss collision risk and sea fog and that the significance of these relationships varied locally.Dividing the specific navigation area made it possible to verify that sea fog has a positive impact on near-miss collision risk.展开更多
文摘为研究中国气象局(China Meteorological Administration,CMA)研发的中国第一代全球再分析产品CRA(CMA Global Reanalysis)对海雾模拟的适用性,将CRA与欧洲中心再分析产品ERA5(the 5th Generation of ECMWF Reanalysis)以及美国国家环境预报中心的再分析产品FNL(Final Reanalysis Data)分别作为WRF(Weather Research and Forecast)模式驱动的初边界条件,对发生在琼州海峡的一次持续性海雾过程进行数值模拟。结果表明:将3种再分析产品作为初始场均能模拟出琼州海峡海雾发展过程。CRA和ERA5模拟的海雾在偏东风下开始发展,风向转为东北风后消散。CRA模拟的海雾强度最强且维持时间最长,FNL模拟的底层风场较早转为东北风,海雾消散早。在垂直方向上,ERA5和CRA模拟的海雾发展高度与实况接近,FNL则明显偏低。CRA中较低的逆温层以及近地层温度将水汽聚集在低层,使得海雾可以持续发展并长时间维持。在加入实时更新的高分辨率海温后,模拟的气海温差场更精细,可反映出琼州海峡中部及东部气海温差小于0.5℃的区域,模拟海雾发展的能力更强。
基金The support of the US Office of Naval Research Global under contract No.N62909-20-1-2080.
文摘Sea spray,which comprises amounts of small ocean droplets,plays a significant role in the air-sea coupling,atmospheric and oceanic dynamics,and climate.However,it remains arduous to arrive at estimates for the efficiency and accuracy of the sea spray induced air-sea heat and salt fluxes.This is because the microphysical process of sea spray evolution in the air is of extreme complexity.In this study,we iteratively calculated the sea spray induced air-sea heat and salt fluxes at various weather condition.To do so,we implemented one novel wave-steepness-dependent sea spray model into a bulk air-sea fluxes algorithm and utilized other sea spray models as comparisons.Based on the improved wave-dependent bulk turbulent algorithm,we observed that despite the negative contribution of sea spray to the sensible heat fluxes,the sea spray positively contributes to the air-sea latent heat fluxes,leading to an overall increase in the total air-sea heat fluxes.The additional heat fluxes caused by sea spray may be the missing critical process that can clarify the discrepancies observed between measured and modelled Tropical Cyclone’s development and intensification.In addition to heat fluxes,we observed that sea spray has significant impacts on the air-sea salt fluxes.As the sea salt particles are one of the main sources of the atmosphere aerosol,our results imply that sea spray could impact global and regional climate.Thus,given the significance of sea spray on the air-sea boundary layer,sea spray effects need to be considered in studies of air-sea interaction,dynamics of atmosphere and ocean.
文摘Sea fog is a disastrous weather phenomenon,posing a risk to the safety of maritime transportation.Dense sea fogs reduce visibility at sea and have frequently caused ship collisions.This study used a geographically weighted regression(GWR)model to explore the spatial non-stationarity of near-miss collision risk,as detected by a vessel conflict ranking operator(VCRO)model from automatic identification system(AIS)data under the influence of sea fog in the Bohai Sea.Sea fog was identified by a machine learning method that was derived from Himawari-8 satellite data.The spatial distributions of near-miss collision risk,sea fog,and the parameters of GWR were mapped.The results showed that sea fog and near-miss collision risk have specific spatial distribution patterns in the Bohai Sea,in which near-miss collision risk in the fog season is significantly higher than that outside the fog season,especially in the northeast(the sea area near Yingkou Port and Bayuquan Port)and the southeast(the sea area near Yantai Port).GWR outputs further indicated a significant correlation between near-miss collision risk and sea fog in fog season,with higher R-squared(0.890 in fog season,2018),than outside the fog season(0.723 in non-fog season,2018).GWR results revealed spatial non-stationarity in the relationships between-near miss collision risk and sea fog and that the significance of these relationships varied locally.Dividing the specific navigation area made it possible to verify that sea fog has a positive impact on near-miss collision risk.
