基于中国气象局(China Meterological Administration,CMA)高分辨率数值预报产品、欧洲中期数值预报中心(the European Center for Medium-range Weather Forecast,ECMWF)精细化数值预报产品和国家级地面观测站数据,采用小波分析方法及...基于中国气象局(China Meterological Administration,CMA)高分辨率数值预报产品、欧洲中期数值预报中心(the European Center for Medium-range Weather Forecast,ECMWF)精细化数值预报产品和国家级地面观测站数据,采用小波分析方法及滑动训练、最优融合等技术对模式误差序列进行时频处理,实现了对模式系统误差和局地误差的订正,发展了西北区智能网格气温客观预报方法(northwest intelligent grid temperature objective prediction method,NWTM)。以2017年3月—2018年2月数据作为训练样本,对2018年3月—2019年1月西北区239个国家基本站进行检验。结果表明:1)NWTM对CMA和ECMWF两种模式产品的气温预报能力有显著的提升;随着预报时效增长,两种模式订正产品的误差增大。2)NWTM对ECMWF西北区最高气温的订正效果要明显优于CMA,但就最低气温而言,NWTM对CMA的订正效果更为显著。其中,就24 h最高气温而言,ECMWF在宁夏的订正效果最好,CMA在青海的订正效果最好;而对于24 h最低气温的预报,CMA在西北4省的订正效果相差不大,ECMWF在陕西的订正效果最好。3)空间误差检验表明:针对最高气温的预报,ECMWF订正产品的订正能力明显优于CMA,特别是在甘肃河西走廊和中东部、陕西北部和南部、宁夏中南部及青海大部。就最低气温的预报而言,ECMWF和CMA对甘肃河东和陕西南部的订正能力较好;ECMWF订正产品在宁夏中南部及青海南部的订正能力高于CMA,而CMA订正产品在陕西中部的订正能力更优。展开更多
Over two dozen global atmospheric chemistry models contributing to the Aerosol Comparisons between Observations and Models(AeroCom)project were used in this study to drive the Los Alamos sea ice model to simulate the ...Over two dozen global atmospheric chemistry models contributing to the Aerosol Comparisons between Observations and Models(AeroCom)project were used in this study to drive the Los Alamos sea ice model to simulate the black carbon(BC)concentration in melting snow on Arctic sea ice.Measurements of BC during the melting season show concentrations in the range 2.8–41.6 ng·g−1(average:15.3 ng·g−1)in the central Arctic Ocean and Canada Basin.Most results from models contributing to the Phase I project were within the 25th and 75th percentiles of the observations,and the multimodel mean was slightly lower than that of the observations.In contrast,there was larger divergence among the Phase II model simulations and the mean value of BC was overestimated.The multimodel mean bias was−3.1(−11.2 to+6.7)ng·g−1 for Phase I models and+3.9(−9.5 to+21.3)ng·g−1 for Phase II models.The differences between the models of the two phases were probably attributable to the updated aerosol scheme in the new contributions,in which removal processes are parameterized by considering the actual dimensions and chemical compositions of the particles.This means the removal mechanism acts in a way that is more selective and leads to more BC particles being transported to the Arctic.In addition,higher spatial resolution could be another important reason for overestimation of BC concentration in snow in Phase II models.展开更多
Based upon the stochastic resonance theory,the formation mechanism of 100-kyr cycles in climate system is numerically studied in the perspective of stochastic dynamics.In this study,firstly we combine the idealized al...Based upon the stochastic resonance theory,the formation mechanism of 100-kyr cycles in climate system is numerically studied in the perspective of stochastic dynamics.In this study,firstly we combine the idealized albedo model with the geological evidence and observation in climate system to construct a new albedo model.Secondly,a bistable nonlinear system is constructed by introducing the albedo model into zero-dimensional energy balance model.Finally,based on this new system,with the solar radiation cycles and stochastic perturbation simultaneously taken into account,the variation of 100-kyr cycles is analyzed by numerical simulations.The results show that,when the noise intensity reaches a certain value,the stochastic resonance can be triggered.However,the noise intensity in this level does not exist in the actual climate system.In order to explain the formation mechanism of 100-kyr glacial-interglacial cycles forced by the weak solar radiation cycles,besides the solar radiation stochastic perturbation,the stochastic dynamic effects of the other "non-solar" radiation stochastic perturbation in the climate change processes should also be considered.The stochastic dynamic simulations taking the two types of stochastic perturbation into consideration show that,when the two types of appropriately observable stochastic perturbation are introduced,the stochastic resonance also can be generated.In this situation,the contribution rate of solar radiation stochastic perturbation is about 38%,which proves the importance of solar radiation stochastic perturbation in the formation of 100-kyr climate cycles.展开更多
文摘基于中国气象局(China Meterological Administration,CMA)高分辨率数值预报产品、欧洲中期数值预报中心(the European Center for Medium-range Weather Forecast,ECMWF)精细化数值预报产品和国家级地面观测站数据,采用小波分析方法及滑动训练、最优融合等技术对模式误差序列进行时频处理,实现了对模式系统误差和局地误差的订正,发展了西北区智能网格气温客观预报方法(northwest intelligent grid temperature objective prediction method,NWTM)。以2017年3月—2018年2月数据作为训练样本,对2018年3月—2019年1月西北区239个国家基本站进行检验。结果表明:1)NWTM对CMA和ECMWF两种模式产品的气温预报能力有显著的提升;随着预报时效增长,两种模式订正产品的误差增大。2)NWTM对ECMWF西北区最高气温的订正效果要明显优于CMA,但就最低气温而言,NWTM对CMA的订正效果更为显著。其中,就24 h最高气温而言,ECMWF在宁夏的订正效果最好,CMA在青海的订正效果最好;而对于24 h最低气温的预报,CMA在西北4省的订正效果相差不大,ECMWF在陕西的订正效果最好。3)空间误差检验表明:针对最高气温的预报,ECMWF订正产品的订正能力明显优于CMA,特别是在甘肃河西走廊和中东部、陕西北部和南部、宁夏中南部及青海大部。就最低气温的预报而言,ECMWF和CMA对甘肃河东和陕西南部的订正能力较好;ECMWF订正产品在宁夏中南部及青海南部的订正能力高于CMA,而CMA订正产品在陕西中部的订正能力更优。
基金This study is funded by the Program of National Natural Science Foundation of China(Grant nos.41675056 and 41991283)。
文摘Over two dozen global atmospheric chemistry models contributing to the Aerosol Comparisons between Observations and Models(AeroCom)project were used in this study to drive the Los Alamos sea ice model to simulate the black carbon(BC)concentration in melting snow on Arctic sea ice.Measurements of BC during the melting season show concentrations in the range 2.8–41.6 ng·g−1(average:15.3 ng·g−1)in the central Arctic Ocean and Canada Basin.Most results from models contributing to the Phase I project were within the 25th and 75th percentiles of the observations,and the multimodel mean was slightly lower than that of the observations.In contrast,there was larger divergence among the Phase II model simulations and the mean value of BC was overestimated.The multimodel mean bias was−3.1(−11.2 to+6.7)ng·g−1 for Phase I models and+3.9(−9.5 to+21.3)ng·g−1 for Phase II models.The differences between the models of the two phases were probably attributable to the updated aerosol scheme in the new contributions,in which removal processes are parameterized by considering the actual dimensions and chemical compositions of the particles.This means the removal mechanism acts in a way that is more selective and leads to more BC particles being transported to the Arctic.In addition,higher spatial resolution could be another important reason for overestimation of BC concentration in snow in Phase II models.
基金supported by the National Natural Science Foundation of China(Grant No.41205083)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Based upon the stochastic resonance theory,the formation mechanism of 100-kyr cycles in climate system is numerically studied in the perspective of stochastic dynamics.In this study,firstly we combine the idealized albedo model with the geological evidence and observation in climate system to construct a new albedo model.Secondly,a bistable nonlinear system is constructed by introducing the albedo model into zero-dimensional energy balance model.Finally,based on this new system,with the solar radiation cycles and stochastic perturbation simultaneously taken into account,the variation of 100-kyr cycles is analyzed by numerical simulations.The results show that,when the noise intensity reaches a certain value,the stochastic resonance can be triggered.However,the noise intensity in this level does not exist in the actual climate system.In order to explain the formation mechanism of 100-kyr glacial-interglacial cycles forced by the weak solar radiation cycles,besides the solar radiation stochastic perturbation,the stochastic dynamic effects of the other "non-solar" radiation stochastic perturbation in the climate change processes should also be considered.The stochastic dynamic simulations taking the two types of stochastic perturbation into consideration show that,when the two types of appropriately observable stochastic perturbation are introduced,the stochastic resonance also can be generated.In this situation,the contribution rate of solar radiation stochastic perturbation is about 38%,which proves the importance of solar radiation stochastic perturbation in the formation of 100-kyr climate cycles.
