Article
Environmental Sciences
Xin Su, Lunche Wang, Ming Zhang, Wenmin Qin, Muhammad Bilal
Summary: The study proposed a land general aerosol algorithm for East Asia, achieving high-precision aerosol property detection through a spectral ratio library and statistical methods. HiPARA algorithm dynamically determined surface reflectance and aerosol types, with detected AOD showing high consistency with AERONET measurements.
REMOTE SENSING OF ENVIRONMENT
(2021)
Article
Environmental Sciences
Jia-Yi Lin, Hua Ho, Zhe-Wen Zheng
Summary: This study utilizes the high temporal image acquisition capability of AHI/Himawari-8 satellite to investigate the detailed progress of TC-induced chlorophyll-a responses (TICRs). The results show that TICRs react much quicker and stronger than previously understood. Additionally, the spatial characteristics of TICRs observed by AHI exhibit marked differences. These new findings are of great significance for understanding the role of TICRs in influencing the regional oceanic environment, marine ecosystem, and local climate.
Article
Geochemistry & Geophysics
Hyunkwang Lim, Jhoon Kim, Seoyoung Lee, Yasuko Kasai, Sang Seo Park
Summary: This study attempted to retrieve aerosol layer height (ALH) using the Advanced Himawari Imager (AHI) to monitor diurnal changes in ALH and understand long-range transport. Aerosol optical properties (AOPs) were retrieved using the green-near infrared (NIR) band and then used to compute the top-of-atmosphere (TOA) reflectance of a highly sensitive band. The ALH was retrieved using the observed and calculated TOA reflectances.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2023)
Article
Geochemistry & Geophysics
Jeong-Eun Park, Goo Kim, Sungwook Hong
Summary: The study demonstrates the generation of GOES-16 ABI green band using Pix2Pix and convolutional neural network techniques, showing high accuracy and applicability in various scientific applications.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2021)
Article
Environmental Sciences
Lan Feng, Xin Su, Lunche Wang, Tao Jiang, Ming Zhang, Jinyang Wu, Wenmin Qin, Yanlong Chen
Summary: The study verified and compared the aerosol products of the Himawari-8 aerosol algorithm versions 2.1 and 3, finding that version 3 had better accuracy but did not meet certain metrics. The analysis results suggest that aerosol type parameters may be the dominant factor determining the aerosol optical depth error.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Electrical & Electronic
Jeong-Eun Park, Yun-Jeong Choi, Jaehoon Jeong, Sungwook Hong
Summary: This article proposes a D2D model based on conditional generative adversarial networks to generate a hypothetical 1.37 μm band. The validation results show that the D2D-generated band is qualitatively similar to the observed band and can contribute significantly to cirrus detection and climatology.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2023)
Article
Geochemistry & Geophysics
Yi Zhang, Shunlin Liang, Tao He, Dongdong Wang, Yunyue Yu, Han Ma
Summary: Surface incident shortwave radiation (ISR), an important component of the surface radiation budget, has been accurately estimated using refined optimization methods applied to new generation geostationary satellites, leading to improved estimations for hourly and diurnal ISR.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Zhonghui Tan, Chao Liu, Shuo Ma, Xin Wang, Jian Shang, Jianjie Wang, Weihua Ai, Wei Yan
Summary: This study presents a machine learning-based multilayer cloud detection algorithm using AHI data, achieving high accuracy in identifying single-layer and multilayer clouds. The algorithm outperforms existing operational cloud products and suggests improvements for cloud top height retrievals by considering cloud vertical structures.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Wenwen Li, Feng Zhang, Han Lin, Xiaoran Chen, Jun Li, Wei Han
Summary: A deep-learning-based cloud detection and classification algorithm has been developed to improve cloud phase discrimination using a combination of observed radiances and simulated clear-sky radiances. The algorithm simultaneously detects clouds, classifies cloud phase, and detects multilayer clouds using deep neural networks (DNNs). The DNN models outperform official Moderate Resolution Imaging Spectroradiometer (MODIS) and AHI products in cloud detection, phase discrimination, and multilayer cloud detection. The algorithm also has the potential to be applied to measurements from other similar instruments.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Weiwei Xu, Wei Wang, Nan Wang, Biyan Chen
Summary: In this study, a new aerosol retrieval algorithm for AHI by integrating regional PM2.5 concentrations was proposed. The algorithm showed better accuracy in retrieving aerosol optical depth (AOD) compared to the existing JAXA L2 algorithm, especially during autumn in the Beijing-Tianjin-Hebei region. The algorithm also demonstrated stable performance regardless of viewing angle.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Aoxuan Chen, Jin Yang, Yan He, Qiangqiang Yuan, Zhengqiang Li, Liye Zhu
Summary: In this study, an ensemble machine-learning approach was developed to obtain a high spatiotemporal resolution dataset of aerosol optical depth (AOD). By filling the data gaps and using interpolation models, a full-coverage AOD dataset of three highly urbanized areas in 2020 was obtained. Validation against in-situ AOD observations showed satisfactory accuracy (R = 0.80), particularly in spring and summer. Overall, this ensemble machine-learning model provides an effective scheme for reconstructing AOD with high resolution, which can advance the near-real-time monitoring of air quality in urban areas.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Qianguang Tu, Yun Zhao, Jing Guo, Chunmei Cheng, Liangliang Shi, Yunwei Yan, Zengzhou Hao
Summary: Analysis of six years of hourly aerosol optical thickness (AOT) data from Himawari-8 revealed significant spatial and temporal variations of aerosols over the China Seas, with a notable diurnal cycle. AOT was generally higher in high latitude seas compared to low latitude seas, with a coastal distribution pattern showing gradual decrease with distance from the coastline. Additionally, AOT exhibited a distinctive diurnal variation, peaking at noon and decreasing in the morning and afternoon.
Article
Meteorology & Atmospheric Sciences
Ling Gao, Lin Chen, Jun Li, Chengcai Li, Lin Zhu
Summary: This study improved the estimation of surface reflectance relationship by considering land cover, NDVI, and scattering angle, and retrieved AOD over land using AHI/H8 observations in 2018. The quality of AOD retrievals was evaluated using ground-based AOD observations from global AErosol RObotic NETwork (AERONET) and China Aerosol Research Network (CARSNET), showing good agreement with ground-based measurements and better performance in depicting diurnal variation compared to JAXA H8 AOD.
ATMOSPHERIC RESEARCH
(2021)
Article
Geochemistry & Geophysics
Ce Zhang, Xiaolei Zou, Zhe-Min Tan
Summary: This article develops an objective method based on TB observations to determine the center positions and eye and eyewall radii of tropical cyclones. The accuracy of the proposed method is validated, and the results show good agreement with the actual track and distribution of cloud and rainbands. The study also reveals the existence of vortex Rossby waves during the rapid intensification of the cyclone, which has important implications for improving cyclone forecasts.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Environmental Sciences
Zengliang Zang, Wei You, Hancheng Ye, Yanfei Liang, Yi Li, Daichun Wang, Yiwen Hu, Peng Yan
Summary: A 3DVAR data assimilation system was developed for aerosol optical depth (AOD) and aerosol concentration observations, which showed significant improvement in the analysis accuracy and forecast skills of aerosols.
Editorial Material
Meteorology & Atmospheric Sciences
Pak-wai Chan, Wei Han, Betty Mak, Xiaohao Qin, Yongzhu Liu, Ruoying Yin, Jincheng Wang
Summary: Forecasting tropical cyclone track and intensity is challenging due to the lack of ocean observations. The meteorological authorities of Chinese mainland and Hong Kong conducted a ground-space-sky observing system experiment and collected enhanced targeted observation data. Similar observation campaigns could be conducted in other ocean basins in the future.
ADVANCES IN ATMOSPHERIC SCIENCES
(2023)
Article
Meteorology & Atmospheric Sciences
Qian-Jin Zhou, Lei Li, Pak-Wai Chan, Xue-Ling Cheng, Chang-Xing Lan, Jia-Chen Su, Yu-Qing He, Hong-Long Yang
Summary: The present study compares the characteristics of gales induced by different weather systems using observational data from a tall tower in South China. It also explores the relationship between gusts of near-surface wind and turbulent momentum fluxes, suggesting a possible mechanism for destructive forces in surface winds. The findings contribute to increasing awareness of gales, improving prediction and prevention of different types of gales, and enhancing wind-resistant design of high-rise buildings.
JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY
(2023)
Article
Meteorology & Atmospheric Sciences
P. W. Chan, H. Y. Lam, K. K. Hon, T. Huang, S. H. L. Yim
Article
Chemistry, Multidisciplinary
Yuzhao Ma, Jiangbei Zhao, Haoran Han, Pak-wai Chan, Xinglong Xiong
Summary: This paper proposes a novel convolutional neural network (CNN) method based on the improved parallel network (ParNet) to effectively identify aircraft wake. The method introduces depthwise separable convolution (DSC) and convolutional block attention module (CBAM) to enhance the model's ability to extract spatial features of the wind field. Using the proposed method on lidar wind field scanning images of Hong Kong International Airport, the aircraft wake can be identified with a recognition accuracy of 98.91% and an F1 value of 98.90%. With only 0.46M model parameters, the aircraft wake can be identified on an ordinary computer.
APPLIED SCIENCES-BASEL
(2023)
Article
Meteorology & Atmospheric Sciences
Qian-Jin Zhou, Lei Li, Pak Wai Chan, Xue-Ling Cheng, Hong-Long Yang, Chang-Xing Lan, Jia-Chen Su
Summary: The study utilizes the time-lagged convergent cross-mapping (LCCM) method and data from the Shenzhen Meteorological Gradient Tower to observe gusts and momentum flux of two super typhoons (STs) and two squall lines (SLs). LCCM reliably identifies coupling relationships in the nonlinear system, and it can identify long-distance interactions of multilevel gusts in different types of gale weather systems. The downward transportation of energy in ST and SL is verified, and the results provide valuable information for validating numerical weather prediction models and for gale hazard prevention.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Yangzhao Gong, Zhizhao Liu, Pak Wai Chan, Kai Kwong Hon
Summary: By analyzing the observational data in the Northwest Pacific region in March and June 2020, it was found that assimilating Sentinel-3 precipitable water vapor (PWV) retrievals into the weather forecast model can significantly improve the rainfall forecast skill score, especially for June.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Yeseul Cho, Jhoon Kim, Jeewoo Lee, Myungje Choi, Hyunkwang Lim, Seoyoung Lee, Jungho Im
Summary: The study estimated the concentration of PM2.5 in East Asia by analyzing satellite data. By considering the spatial and temporal characteristics of ground-based PM2.5 measurements, a model was developed to predict PM2.5 concentrations. The study demonstrates the potential of satellite-based estimation for areas with limited measuring stations.
ATMOSPHERIC RESEARCH
(2023)
Article
Meteorology & Atmospheric Sciences
P. W. Chan, K. K. Lai, Q. S. LI
Summary: This study examines the performance of a meteorological model in large-eddy simulations in capturing low-level wind shear and turbulent flow at the Hong Kong International Airport during the springtime wind-shear season from January to April 2021. The results show that the model reasonably captures the low-level wind shear based on statistical comparison and two selected cases. The turbulent flow is also reproduced well, as indicated by structure function and eddy dissipation rate analysis. The paper suggests that large-eddy simulation has reasonable skill in capturing low-level wind shear using a large wind-shear sample.
METEOROLOGISCHE ZEITSCHRIFT
(2023)
Article
Mechanics
Jian Wang, Xin-Yuan Liu, E. Deng, Yi-Qing Ni, Pak-Wai Chan, Wei-Chao Yang, Yan-Ke Tan
Summary: This paper compares the results of wind tunnel tests and numerical simulations to determine the formation mechanism of the acceleration effect in gorge terrains under crosswinds. The results show that the most dramatic acceleration reaches 1.28-1.4 times the incoming wind speed when the mountain spacing is zero. The paper also discusses the effect of Reynolds number on the results and provides a reference for the design of windproof facilities in gorge terrains.
Article
Environmental Sciences
Alexei Lyapustin, Yujie Wang, Myungje Choi, Xiaoxiong Xiong, Amit Angal, Aisheng Wu, David R. Doelling, Rajendra Bhatt, Sujung Go, Sergey Korkin, Bryan Franz, Gerhardt Meister, Andrew M. Sayer, Miguel Roman, Robert E. Holz, Kerry Meyer, James Gleason, Robert Levy
Summary: By applying the MAIAC-based vicarious calibration technique, this study analyzed the calibration of VIIRS on SNPP and NOAA-20 satellites over the Libya-4 desert site. The results showed agreement with independent calibration results and indicated the continuity and consistency of MAIAC records, ensuring a smooth transition from MODIS to VIIRS.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Environmental Sciences
Junyi He, Qiusheng Li, Pak-Wai Chan, Chun-Wing Choy, Betty Mak, Ching-Chi Lam, Hong-Yan Luo
Summary: This paper documents and analyzes extensive surface and upper air measurements of Typhoon Talim, which occurred in July 2023 over the northern part of the South China Sea. The study reveals that the wind profiles of the typhoon can be accurately described using the log law and power law within the first 1000 meters above the sea surface. It also observes the presence of a low-level jet in the lower troposphere at around 1000 meters, as evidenced by radar wind profilers. Additionally, the study utilizes Doppler LIDAR and ocean radar data to analyze the surface wind observations of the typhoon, providing valuable insights into the understanding of tropical cyclone structures and their applications in wind engineering.
Article
Meteorology & Atmospheric Sciences
Wu Wen, Lei Li, P. W. Chan, Yuan-Yuan Liu, Min Wei
Summary: Haze pollution, a major environmental problem in China, can be mitigated by accurate haze forecasts. This study examines the usability of different machine learning and deep learning methods for visibility forecasting and confirms their accuracy through various parameters.
Article
Engineering, Electrical & Electronic
Chun Shen, Weiwei Tang, Hang Gao, Xuesong Wang, Pak-Wai Chan, Kai-Kwong Hon, Jianbing Li
Summary: Aircraft wake is a pair of counter-rotating vortices generated behind the aircraft, which can greatly impact the safety of fast takeoff and landing of aircraft and limit the improvement of airport capacity. The current wake parameter retrieval methods cannot locate the wake vortex's position and estimate its strength level in real time. To address this issue, a novel algorithm based on the YOLOv5s deep learning network is proposed, which demonstrates superiority in accuracy and robustness compared to state-of-the-art object detection approaches.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2023)
Article
Meteorology & Atmospheric Sciences
P. W. Chan, K. K. Lai, Q. S. Li
Summary: This paper documents the occurrence of dust devils at Hong Kong International Airport in two consecutive days in the summer of 2019. It is found that these dust devils are related to the sea breeze convergence lines and exhibit anticyclonic characteristics. The paper discusses the difficulties in microscale simulation of sea breeze circulation in complex terrain areas and successfully reproduces the rotation direction of the dust devil flow through computer simulation. It is hoped that this paper can serve as a useful reference for future studies on dust devils.
Article
Environmental Sciences
Seoyoung Lee, Myungje Choi, Jhoon Kim, Young-Je Park, Jong-Kuk Choi, Hyunkwang Lim, Jeewoo Lee, Minseok Kim, Yeseul Cho
Summary: In this study, the YAER algorithm was extended to GOCI-II data and the first results of aerosol optical properties retrieved from GOCI-II data were presented. The results showed that GOCI-II aerosol retrievals have a consistent spatial distribution with those from GOCI and provide AOD at a higher spatial resolution, revealing finer changes in aerosol concentrations.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
