Vector winds play a crucial role in weather and climate,as well as the effective utilization of wind energy resources.However,limited research has been conducted on treating the wind field as a vector field in the eva...Vector winds play a crucial role in weather and climate,as well as the effective utilization of wind energy resources.However,limited research has been conducted on treating the wind field as a vector field in the evaluation of numerical weather prediction models.In this study,the authors treat vector winds as a whole by employing a vector field evaluation method,and evaluate the mesoscale model of the China Meteorological Administration(CMA-MESO)and ECMWF forecast,with reference to ERA5 reanalysis,in terms of multiple aspects of vector winds over eastern China in 2022.The results show that the ECMWF forecast is superior to CMA-MESO in predicting the spatial distribution and intensity of 10-m vector winds.Both models overestimate the wind speed in East China,and CMA-MESO overestimates the wind speed to a greater extent.The forecasting skill of the vector wind field in both models decreases with increasing lead time.The forecasting skill of CMA-MESO fluctuates more and decreases faster than that of the ECMWF forecast.There is a significant negative correlation between the model vector wind forecasting skill and terrain height.This study provides a scientific evaluation of the local application of vector wind forecasts of the CMA-MESO model and ECMWF forecast.展开更多
Different choices of control variables in variational assimilation can bring about different influences on the analyzed atmospheric state. Based on the WRF model＇s three-dimensional variational assimilation system, t...Different choices of control variables in variational assimilation can bring about different influences on the analyzed atmospheric state. Based on the WRF model＇s three-dimensional variational assimilation system, this study compares the be- havior of two momentum control variable options-streamfunction velocity potential （ψ-χ） and horizontal wind components （U-V）-in radar wind data assimilation for a squall line case that occurred in Jiangsu Province on 24 August 2014. The wind increment from the single observation test shows that the ψ-χ control variable scheme produces negative increments in the neighborhood around the observation point because streamfunction and velocity potential preserve integrals of velocity. On the contrary, the U-V control variable scheme objectively reflects the information of the observation itself. Furthermore, radial velocity data from 17 Doppler radars in eastern China are assimilated. As compared to the impact of conventional observation, the assimilation of radar radial velocity based on the U-V control variable scheme significantly improves the mesoscale dynamic field in the initial condition. The enhanced low-level jet stream, water vapor convergence and low-level wind shear result in better squall line forecasting. However, the ψ-χ control variable scheme generates a discontinuous wind field and unrealistic convergence/divergence in the analyzed field, which lead to a degraded precipitation forecast.展开更多
Stretchable afterglow materials have garnered widespread attention owing to their unique combination of optical properties and mechanical flexibility.However,achieving a crystal environment to suppress the non-radiati...Stretchable afterglow materials have garnered widespread attention owing to their unique combination of optical properties and mechanical flexibility.However,achieving a crystal environment to suppress the non-radiative transition of triplet excitons poses a challenge in constructing stretchable afterglow materials.Herein,we utilize an in situ supersaturated crystallization strategy to form afterglow microcrystals within a hydrogel matrix.This approach enables afterglow emission with a lifetime of 695 ms while maintaining high stretchability with tensile stress surpassing 398 kPa,extensibility over 400%and a high water content of 65.21%.Moreover,the universal supersaturated crystallization strategy allows for conferring tunable afterglow performance.Successful demonstrations in hydrogel 3D printing and anticounterfeiting purposes showcase the potential for advanced applications of 3D printable afterglow hydrogels.This investigation provides guidelines for generally designing efficient afterglow hydrogels and addresses the inherent contradiction between flexibility and rigid in stretchable afterglow materials.展开更多
基金primarily supported by the National Key R&D Program of China[grant number 2021YFC3000904]the Jiangsu Provincial Key Technology R&D Program[grant number BE2022851]National Natural Science Foundation of China[grant number 42405035]。
文摘Vector winds play a crucial role in weather and climate,as well as the effective utilization of wind energy resources.However,limited research has been conducted on treating the wind field as a vector field in the evaluation of numerical weather prediction models.In this study,the authors treat vector winds as a whole by employing a vector field evaluation method,and evaluate the mesoscale model of the China Meteorological Administration(CMA-MESO)and ECMWF forecast,with reference to ERA5 reanalysis,in terms of multiple aspects of vector winds over eastern China in 2022.The results show that the ECMWF forecast is superior to CMA-MESO in predicting the spatial distribution and intensity of 10-m vector winds.Both models overestimate the wind speed in East China,and CMA-MESO overestimates the wind speed to a greater extent.The forecasting skill of the vector wind field in both models decreases with increasing lead time.The forecasting skill of CMA-MESO fluctuates more and decreases faster than that of the ECMWF forecast.There is a significant negative correlation between the model vector wind forecasting skill and terrain height.This study provides a scientific evaluation of the local application of vector wind forecasts of the CMA-MESO model and ECMWF forecast.
基金jointly supported by the National Fundamental Research(973)Program of China(Grant Nos.2015CB452801 and 2013CB430100)the Jiangsu Meteorological Bureau Research Fund Project for the Youth(Grant Nos.Q201514 and Q201407)+3 种基金the Shandong Institute of Meteorological Sciences Research Fund Project(Grant No.SDQXKF2015M10)the Jiangsu Provincial Key Technology R&D Program(Grant No.BE2013730)the Jiangsu Meteorological Bureau Key Research Fund Project(Grant No.KZ201502)the National Key Technology R&D Program(Grant No.2014BAG01B01)
文摘Different choices of control variables in variational assimilation can bring about different influences on the analyzed atmospheric state. Based on the WRF model＇s three-dimensional variational assimilation system, this study compares the be- havior of two momentum control variable options-streamfunction velocity potential （ψ-χ） and horizontal wind components （U-V）-in radar wind data assimilation for a squall line case that occurred in Jiangsu Province on 24 August 2014. The wind increment from the single observation test shows that the ψ-χ control variable scheme produces negative increments in the neighborhood around the observation point because streamfunction and velocity potential preserve integrals of velocity. On the contrary, the U-V control variable scheme objectively reflects the information of the observation itself. Furthermore, radial velocity data from 17 Doppler radars in eastern China are assimilated. As compared to the impact of conventional observation, the assimilation of radar radial velocity based on the U-V control variable scheme significantly improves the mesoscale dynamic field in the initial condition. The enhanced low-level jet stream, water vapor convergence and low-level wind shear result in better squall line forecasting. However, the ψ-χ control variable scheme generates a discontinuous wind field and unrealistic convergence/divergence in the analyzed field, which lead to a degraded precipitation forecast.
基金supported inpart by the National Natural Science Foundation of China(22322106,22075149,62075102,22105104,22305126,62174085 and 62288102)the Open Research Fund of Songshan Lake Materials Laboratory(2022SLABFN16)+1 种基金the Hua Li Talents Program of Nanjing University of Posts and Telecommunications,the Project of State Key Laboratory of Organic Electronics and Information Displays,Nanjing University of Posts and Tele-communications,(No.GDX2024010002)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_1146 and SJCX22_0250).
文摘Stretchable afterglow materials have garnered widespread attention owing to their unique combination of optical properties and mechanical flexibility.However,achieving a crystal environment to suppress the non-radiative transition of triplet excitons poses a challenge in constructing stretchable afterglow materials.Herein,we utilize an in situ supersaturated crystallization strategy to form afterglow microcrystals within a hydrogel matrix.This approach enables afterglow emission with a lifetime of 695 ms while maintaining high stretchability with tensile stress surpassing 398 kPa,extensibility over 400%and a high water content of 65.21%.Moreover,the universal supersaturated crystallization strategy allows for conferring tunable afterglow performance.Successful demonstrations in hydrogel 3D printing and anticounterfeiting purposes showcase the potential for advanced applications of 3D printable afterglow hydrogels.This investigation provides guidelines for generally designing efficient afterglow hydrogels and addresses the inherent contradiction between flexibility and rigid in stretchable afterglow materials.
基金supported in part by the National Natural Science Foundation of China(22075149,22105104,62075102,and 22275097)Jiangsu Specially-Appointed Professor Plan,the Six Talent Plan of Jiangsu Province(XCL-049),HuaLi Talents Program of Nanjing University of Posts and Telecommunications,the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)(2022-skllmd-01)+3 种基金the Open Research Fund of Songshan Lake Materials Laboratory(2022SLABFN16)the Innovation and Entrepreneurship Program of Jiangsu Province,China(JSSCBS20210536)the Fifth 333-Project of Jiangsu Province of China(BRA2019080)Nanjing University of Posts and Telecommunications Start-up Fund(NY220151 and NY219007).
