This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is ...This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.展开更多
The global intensification of harmful algal blooms severely compromises freshwater ecosystems,threatening biodiversity and critical ecosystem services through toxin exposure,hypoxia,and water quality degradation.Bloom...The global intensification of harmful algal blooms severely compromises freshwater ecosystems,threatening biodiversity and critical ecosystem services through toxin exposure,hypoxia,and water quality degradation.Bloom formation involves a complex interplay of nutrient dynamics,hydrology,and microbial activity.Although subsurface processes-such as the release of sediment-bound nutrients and the germination of dormant cyanobacteria-are thought crucial to bloom initiation,these phenomena occur at fine spatiotemporal scales beyond the reach of conventional monitoring.As a result,the exact,rapidly evolving triggers of bloom emergence remain mostly unknown.Here we show meter-scale chlorophyll a(Chl-a)plumes rising from the sediment-water interface,triggered by heavy rainfall and directly seeding surface blooms.We captured these dynamics using a custom underwater drone that collected over 2.8 million data points at 5-m horizontal and 1-m vertical resolution.Algal blooms exhibit a clear vertical sequence:anomalous Chl-a levels first appear in deep benthic layers after rainfall-driven resuspension,then intensify simultaneously across near-bed depths,and finally reach the surface after a median lag of 0.8-1.5 days.These observations provide in situ evidence associating benthic algal seed stocks with surface bloom initiation,revealing that the origin and spatial heterogeneity of such events arise from rainfall-driven disturbances at the sediment-water interface.This robotic approach not only deciphers the subsurface origins of algal blooms but also empowers predictive modeling and adaptive management strategies,advancing global efforts to combat eutrophication amid escalating climate pressures and safeguard vital water resources.展开更多
In this Letter,we present a low-cost,high-resolution spectrometer design for ultra-high resolution optical coherence tomography(UHR-OCT),in which multiple standard achromatic lenses are combined to replace the expensi...In this Letter,we present a low-cost,high-resolution spectrometer design for ultra-high resolution optical coherence tomography(UHR-OCT),in which multiple standard achromatic lenses are combined to replace the expensive F-theta lens to achieve a comparable performance.For UHR-OCT,the spectrometer plays an important role in high-quality 3D image reconstruction.Typically,an F-theta lens is used in spectrometers as the Fourier lens to focus the dispersed light on the sensor array,and this F-theta lens is one of the most expensive components in spectrometers.The advantage of F-theta lens over the most widely used achromatic lens is that the aberrations(mainly spherical aberration,SA)are corrected,so the foci of the dispersed optical beams(at different wavelengths)with different incident angles could be placed on the sensor array simultaneously.For the achromatic lens,the foci of the center part of the spectrum are farther than those on the side in the longitudinal direction,causing degradations of the spectral resolution.Furthermore,in comparison with the achromatic lens with the same focal length,those with smaller diameters have stronger SA,but small lenses are what we need for making spectrometers compact and stable.In this work,we propose a simple method of using multiple long-focal-length achromatic lenses together to replace the F-theta lens,which is>8-fold cheaper based on the price of optical components from Thorlabs,US.Both simulations and in vivo experiments were implemented to demonstrate the performance of the proposed method.展开更多
文摘This paper presents our endeavors in developing the large-scale, ultra-high-resolution E3SM Land Model (uELM), specifically designed for exascale computers furnished with accelerators such as Nvidia GPUs. The uELM is a sophisticated code that substantially relies on High-Performance Computing (HPC) environments, necessitating particular machine and software configurations. To facilitate community-based uELM developments employing GPUs, we have created a portable, standalone software environment preconfigured with uELM input datasets, simulation cases, and source code. This environment, utilizing Docker, encompasses all essential code, libraries, and system software for uELM development on GPUs. It also features a functional unit test framework and an offline model testbed for comprehensive numerical experiments. From a technical perspective, the paper discusses GPU-ready container generations, uELM code management, and input data distribution across computational platforms. Lastly, the paper demonstrates the use of environment for functional unit testing, end-to-end simulation on CPUs and GPUs, and collaborative code development.
基金supported by the National Natural Science Foundation of China(No.52321005,No.52293443,and No.52230004)Shenzhen Science and Technology Program(No.KQTD20190929172630447)+2 种基金Shenzhen Key Research Project(No.GXWD20220817145054002)Shenzhen Natural Science Foundation(No.JCYJ20240813104812017)Talent Recruitment Project of Guangdong(No.2021QN020106).
文摘The global intensification of harmful algal blooms severely compromises freshwater ecosystems,threatening biodiversity and critical ecosystem services through toxin exposure,hypoxia,and water quality degradation.Bloom formation involves a complex interplay of nutrient dynamics,hydrology,and microbial activity.Although subsurface processes-such as the release of sediment-bound nutrients and the germination of dormant cyanobacteria-are thought crucial to bloom initiation,these phenomena occur at fine spatiotemporal scales beyond the reach of conventional monitoring.As a result,the exact,rapidly evolving triggers of bloom emergence remain mostly unknown.Here we show meter-scale chlorophyll a(Chl-a)plumes rising from the sediment-water interface,triggered by heavy rainfall and directly seeding surface blooms.We captured these dynamics using a custom underwater drone that collected over 2.8 million data points at 5-m horizontal and 1-m vertical resolution.Algal blooms exhibit a clear vertical sequence:anomalous Chl-a levels first appear in deep benthic layers after rainfall-driven resuspension,then intensify simultaneously across near-bed depths,and finally reach the surface after a median lag of 0.8-1.5 days.These observations provide in situ evidence associating benthic algal seed stocks with surface bloom initiation,revealing that the origin and spatial heterogeneity of such events arise from rainfall-driven disturbances at the sediment-water interface.This robotic approach not only deciphers the subsurface origins of algal blooms but also empowers predictive modeling and adaptive management strategies,advancing global efforts to combat eutrophication amid escalating climate pressures and safeguard vital water resources.
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20210227).
文摘In this Letter,we present a low-cost,high-resolution spectrometer design for ultra-high resolution optical coherence tomography(UHR-OCT),in which multiple standard achromatic lenses are combined to replace the expensive F-theta lens to achieve a comparable performance.For UHR-OCT,the spectrometer plays an important role in high-quality 3D image reconstruction.Typically,an F-theta lens is used in spectrometers as the Fourier lens to focus the dispersed light on the sensor array,and this F-theta lens is one of the most expensive components in spectrometers.The advantage of F-theta lens over the most widely used achromatic lens is that the aberrations(mainly spherical aberration,SA)are corrected,so the foci of the dispersed optical beams(at different wavelengths)with different incident angles could be placed on the sensor array simultaneously.For the achromatic lens,the foci of the center part of the spectrum are farther than those on the side in the longitudinal direction,causing degradations of the spectral resolution.Furthermore,in comparison with the achromatic lens with the same focal length,those with smaller diameters have stronger SA,but small lenses are what we need for making spectrometers compact and stable.In this work,we propose a simple method of using multiple long-focal-length achromatic lenses together to replace the F-theta lens,which is>8-fold cheaper based on the price of optical components from Thorlabs,US.Both simulations and in vivo experiments were implemented to demonstrate the performance of the proposed method.
