Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse i...Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse impulse coupling effect. Here, we designed a new recoil impulse experimental measurement system of non-contact, multidegrees of freedom, and multi-pulse irradiation. The system used a low-pressure and low-temperature vacuum chamber to simulate the space environment, the pinning effect of magnetic levitation to achieve aluminum target suspension, and high-speed cameras to record the displacement over time to calculate the impulse of the target.Then the impulse coupling experiment of multi-pulse laser irradiation on the aluminum target was performed.The result shows that the multi-pulse impulse coupling effect is not the linear accumulation of coupling results by every single-pulse and multi-pulse coefficient that decreases with the increase of the number of pulses, and eventually stabilizes as the decrease gets smaller.展开更多
With advancements in remote sensing technology and retrieval algorithms,many high-performance aerosol observation satellites have enriched the spatial and temporal coverage of aerosol optical depth(AOD)data,providing ...With advancements in remote sensing technology and retrieval algorithms,many high-performance aerosol observation satellites have enriched the spatial and temporal coverage of aerosol optical depth(AOD)data,providing rich assimilation data for numerical model simulation and forecast.In this study,the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem)was employed to simulate the hourly AOD across China and its neighboring regions during summer of 2017 and winter of 2017/2018.The AOD observations from the Himawar-8 and Moderate Resolution Imaging Spectroradiometer(MODIS)satellites were assimilated by using a three-dimensional variational assimilation method in the Gridpoint Statistical Interpolation(GSI)system.The results implied that the AOD data assimilation from either Himawar-8 or MODIS was more consistent with Modern-Era Retrospective analysis for Research and Applications,Version 2(MERRA-2)reanalysis data and ground station observations.The performance of AOD data assimilation was highly dependent on effective satellite data.When both the MODIS and Himawar-8 AOD data were assimilated,the simulation showed significant improvement in summer,while this enhancement was less pronounced in winter.For severe polluted areas(e.g.,the Sichuan basin,and central and eastern China),simultaneous assimilation of both satellites data led to better performance than did individual satellite data assimilation,particularly over the Sichuan basin.In the clean region of the Qinghai–Xizang Plateau,the improvement was even more significant in winter.Moreover,the simultaneous assimilation of both satellites produced more consistent results with site-based observations than the assimilation of data from either satellite alone.This study reveals that missing satellite remote sensing data significantly impacts assimilation performance.Enhancing the assimilation data ratio through artificial intelligence-based multi-source data fusion represents a key focus for future research.展开更多
Urbanization-related precipitation and surface runoff changes have been widely investigated,but few studies have directly quantified these changes and their link to urbanization in the hydrological cycle.A two-way dyn...Urbanization-related precipitation and surface runoff changes have been widely investigated,but few studies have directly quantified these changes and their link to urbanization in the hydrological cycle.A two-way dynamically coupled atmospheric–hydrological modeling system,Weather Research and Forecasting(WRF)-Hydro,has been applied in this study to perform the quantification.The offline WRF-Hydro was first calibrated and validated for several flooding events against gauge observed streamflow data,with the Nash–Sutcliffe efficiency reaching 0.9.Compared to the WRF model,WRF-Hydro resolves more detailed rainfall pattern features and reproduces the gauge rainfall with a correlation coefficient of 0.8.Then,the impact of urbanization on hydrometeorological processes was investigated with coupled WRF-Hydro sensitivity simulations over the Qinhuai River basin of China during 2 June–31 July 2015.The results indicate that urbanization enhances regional precipitation,resulting in an indirect increase in surface runoff,overland flow,and streamflow by 16.7,93.5,and 111.2 mm,respectively;however,the impervious area results in higher surface runoff,overland flow,and streamflow.Moreover,changes in main hydrometeorological processes further impact the atmospheric–terrestrial water budget,resulting in a decrease in terrestrial water storage and an increase(a decrease)in precipitable water storage in the middle(lower)parts of the lower troposphere.These changes are likely associated with the warmer urban environment than rural areas.Increased water vapor and strengthened convective conditions in the middle part of the lower troposphere due to urban warming are advantageous to the formation of precipitation in urban areas,which in turn increases surface runoff,thereby facilitating the water cycle and altering the atmospheric–terrestrial water budget.展开更多
文摘Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse impulse coupling effect. Here, we designed a new recoil impulse experimental measurement system of non-contact, multidegrees of freedom, and multi-pulse irradiation. The system used a low-pressure and low-temperature vacuum chamber to simulate the space environment, the pinning effect of magnetic levitation to achieve aluminum target suspension, and high-speed cameras to record the displacement over time to calculate the impulse of the target.Then the impulse coupling experiment of multi-pulse laser irradiation on the aluminum target was performed.The result shows that the multi-pulse impulse coupling effect is not the linear accumulation of coupling results by every single-pulse and multi-pulse coefficient that decreases with the increase of the number of pulses, and eventually stabilizes as the decrease gets smaller.
基金Supported by the National Key Research and Development Program of China(2023YFC3706304)National Natural Science Foundation of China(41975131)+1 种基金Key Laboratory of Meteorological Disaster(KLME),Ministry of Education&Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CICFEMD),Nanjing University of Information Science&Technology,Nanjing,China(KLME201804)Basic Research and Operational Special Project of Chinese Academy of Meteorological Sciences(2023Z021)。
文摘With advancements in remote sensing technology and retrieval algorithms,many high-performance aerosol observation satellites have enriched the spatial and temporal coverage of aerosol optical depth(AOD)data,providing rich assimilation data for numerical model simulation and forecast.In this study,the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem)was employed to simulate the hourly AOD across China and its neighboring regions during summer of 2017 and winter of 2017/2018.The AOD observations from the Himawar-8 and Moderate Resolution Imaging Spectroradiometer(MODIS)satellites were assimilated by using a three-dimensional variational assimilation method in the Gridpoint Statistical Interpolation(GSI)system.The results implied that the AOD data assimilation from either Himawar-8 or MODIS was more consistent with Modern-Era Retrospective analysis for Research and Applications,Version 2(MERRA-2)reanalysis data and ground station observations.The performance of AOD data assimilation was highly dependent on effective satellite data.When both the MODIS and Himawar-8 AOD data were assimilated,the simulation showed significant improvement in summer,while this enhancement was less pronounced in winter.For severe polluted areas(e.g.,the Sichuan basin,and central and eastern China),simultaneous assimilation of both satellites data led to better performance than did individual satellite data assimilation,particularly over the Sichuan basin.In the clean region of the Qinghai–Xizang Plateau,the improvement was even more significant in winter.Moreover,the simultaneous assimilation of both satellites produced more consistent results with site-based observations than the assimilation of data from either satellite alone.This study reveals that missing satellite remote sensing data significantly impacts assimilation performance.Enhancing the assimilation data ratio through artificial intelligence-based multi-source data fusion represents a key focus for future research.
基金Supported by the National Natural Science Foundation of China(42205193 and 42330608)Open Fundation of China Meteorological Administration Hydro-Meteorology Key Laboratory(23SWQXM001)Young Beijing Scholars Program(2018-007)。
文摘Urbanization-related precipitation and surface runoff changes have been widely investigated,but few studies have directly quantified these changes and their link to urbanization in the hydrological cycle.A two-way dynamically coupled atmospheric–hydrological modeling system,Weather Research and Forecasting(WRF)-Hydro,has been applied in this study to perform the quantification.The offline WRF-Hydro was first calibrated and validated for several flooding events against gauge observed streamflow data,with the Nash–Sutcliffe efficiency reaching 0.9.Compared to the WRF model,WRF-Hydro resolves more detailed rainfall pattern features and reproduces the gauge rainfall with a correlation coefficient of 0.8.Then,the impact of urbanization on hydrometeorological processes was investigated with coupled WRF-Hydro sensitivity simulations over the Qinhuai River basin of China during 2 June–31 July 2015.The results indicate that urbanization enhances regional precipitation,resulting in an indirect increase in surface runoff,overland flow,and streamflow by 16.7,93.5,and 111.2 mm,respectively;however,the impervious area results in higher surface runoff,overland flow,and streamflow.Moreover,changes in main hydrometeorological processes further impact the atmospheric–terrestrial water budget,resulting in a decrease in terrestrial water storage and an increase(a decrease)in precipitable water storage in the middle(lower)parts of the lower troposphere.These changes are likely associated with the warmer urban environment than rural areas.Increased water vapor and strengthened convective conditions in the middle part of the lower troposphere due to urban warming are advantageous to the formation of precipitation in urban areas,which in turn increases surface runoff,thereby facilitating the water cycle and altering the atmospheric–terrestrial water budget.
