index.json

[{"authors":["admin"],"categories":null,"content":"Wangshu Tan currently works at School of Optics and Photonics, Beijing Institute of Technology as a post-doctoral researcher. His research interest is lidar remote sensing of atmospheric parameters (e.g. temperature, wind, aerosols, clouds, and water vapor) and their impacts on environment, weather, and climate. Wangshu is looking for collaborators on lidar remote sensing of atmospheric parameters and corresponding applications.\n","date":-62135596800,"expirydate":-62135596800,"kind":"taxonomy","lang":"en","lastmod":-62135596800,"objectID":"2525497d367e79493fd32b198b28f040","permalink":"https://tanwangshu.com/authors/admin/","publishdate":"0001-01-01T00:00:00Z","relpermalink":"/authors/admin/","section":"authors","summary":"Wangshu Tan currently works at School of Optics and Photonics, Beijing Institute of Technology as a post-doctoral researcher. His research interest is lidar remote sensing of atmospheric parameters (e.g. temperature, wind, aerosols, clouds, and water vapor) and their impacts on environment, weather, and climate. Wangshu is looking for collaborators on lidar remote sensing of atmospheric parameters and corresponding applications.","tags":null,"title":"Wangshu Tan","type":"authors"},{"authors":[],"categories":[],"content":"","date":1639113515,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113515,"objectID":"df93b72cca2d7336883ecbfdc71a4a21","permalink":"https://tanwangshu.com/publication/determination-of-equivalent-black-carbon-mass-concentration-from-aerosol-light-absorption-using-variable-mass-absorption-cross-section/","publishdate":"2021-12-10T13:18:35+08:00","relpermalink":"/publication/determination-of-equivalent-black-carbon-mass-concentration-from-aerosol-light-absorption-using-variable-mass-absorption-cross-section/","section":"publication","summary":"","tags":[],"title":"Determination of Equivalent Black Carbon Mass Concentration From Aerosol Light Absorption Using Variable Mass Absorption Cross Section","type":"publication"},{"authors":[],"categories":[],"content":"","date":1639113442,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113442,"objectID":"aa3de97d7223a18755f5752a1d32c883","permalink":"https://tanwangshu.com/publication/retrieval-of-water-cloud-optical-and-microphysical-properties-from-combined-multiwavelength-lidar-and-radar-data/","publishdate":"2021-12-10T13:17:22+08:00","relpermalink":"/publication/retrieval-of-water-cloud-optical-and-microphysical-properties-from-combined-multiwavelength-lidar-and-radar-data/","section":"publication","summary":"","tags":[],"title":"Retrieval of Water Cloud Optical and Microphysical Properties From Combined Multiwavelength Lidar and Radar Data","type":"publication"},{"authors":[],"categories":[],"content":"","date":1639113340,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113340,"objectID":"31965182dd63d265f395b151ff71ac3d","permalink":"https://tanwangshu.com/publication/retrieval-of-aerosol-liquid-water-content-from-high-spectral-resolution-lidar/","publishdate":"2021-12-10T13:15:40+08:00","relpermalink":"/publication/retrieval-of-aerosol-liquid-water-content-from-high-spectral-resolution-lidar/","section":"publication","summary":"","tags":[],"title":"Retrieval of Aerosol Liquid Water Content From High Spectral Resolution Lidar","type":"publication"},{"authors":[],"categories":[],"content":"","date":1639113138,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113138,"objectID":"5d9b90ae9af8de8e25eccd32eb64ed7b","permalink":"https://tanwangshu.com/publication/variability-of-surface-aerosol-properties-at-an-urban-site-in-beijing-based-on-two-years-of-insitu-measurements/","publishdate":"2021-12-10T13:12:18+08:00","relpermalink":"/publication/variability-of-surface-aerosol-properties-at-an-urban-site-in-beijing-based-on-two-years-of-insitu-measurements/","section":"publication","summary":"","tags":[],"title":"Variability of Surface Aerosol Properties at an Urban Site in Beijing Based on Two Years of In–situ Measurements","type":"publication"},{"authors":[],"categories":[],"content":"","date":1639113108,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113108,"objectID":"24e413d34fa42c3b11006a1e92800bb1","permalink":"https://tanwangshu.com/publication/new-correction-method-for-the-scattering-coefficient-measurements-of-a-threewavelength-nephelometer/","publishdate":"2021-12-10T13:11:48+08:00","relpermalink":"/publication/new-correction-method-for-the-scattering-coefficient-measurements-of-a-threewavelength-nephelometer/","section":"publication","summary":"","tags":[],"title":"New Correction Method for the Scattering Coefficient Measurements of a Three–wavelength Nephelometer","type":"publication"},{"authors":[],"categories":[],"content":"","date":1639113011,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1639113011,"objectID":"b54377d2cf7b952fe8a810f83e623da6","permalink":"https://tanwangshu.com/publication/study-of-the-seasonal-variation-in-aeolus-wind-product-performance-over-china-using-era5-and-radiosonde-data/","publishdate":"2021-12-10T13:10:11+08:00","relpermalink":"/publication/study-of-the-seasonal-variation-in-aeolus-wind-product-performance-over-china-using-era5-and-radiosonde-data/","section":"publication","summary":"","tags":[],"title":"Study of the Seasonal Variation in Aeolus Wind Product Performance Over China Using ERA5 and Radiosonde Data","type":"publication"},{"authors":["Tianning Su","Zhanqing Li","Chengcai Li","Jing Li","Wenchao Han","Chuanyang Shen","Wangshu Tan","Jing Wei","Jianping Guo"],"categories":[],"content":"","date":1585238400,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1585238400,"objectID":"61b492ce3f87e2eb8b23be5c647a690f","permalink":"https://tanwangshu.com/publication/the-significant-impact-of-aerosol-vertical-structure-on-lower-atmosphere-stability-and-its-critical-role-in-aerosolplanetary-boundary-layer-pbl-interactions/","publishdate":"2021-12-10T12:15:14+08:00","relpermalink":"/publication/the-significant-impact-of-aerosol-vertical-structure-on-lower-atmosphere-stability-and-its-critical-role-in-aerosolplanetary-boundary-layer-pbl-interactions/","section":"publication","summary":"We study the role of aerosol vertical distribution in thermodynamic stability and PBL development. Under different aerosol vertical structures, the diurnal cycles of PBLH and PM2.5 show distinct characteristics. Large differences in the heating rate affect atmospheric buoyancy and stability differently under different aerosol structures. As a result, the aerosol–PBL interaction can be strengthened by the inverse aerosol structure and potentially neutralized by the decreasing structure.","tags":[],"title":"The Significant Impact of Aerosol Vertical Structure on Lower Atmosphere Stability and Its Critical Role in Aerosol–Planetary Boundary Layer (PBL) Interactions","type":"publication"},{"authors":["Wangshu Tan","Yingli Yu","Chengcai Li","Jing Li","Ling Kang","Huabin Dong","Limin Zeng","Tong Zhu"],"categories":[],"content":"","date":1584374400,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1584374400,"objectID":"d39f40b4f99137d29c6ee5c74fb0f8d6","permalink":"https://tanwangshu.com/publication/profiling-aerosol-liquid-water-content-using-a-polarization-lidar/","publishdate":"2021-12-10T12:11:17+08:00","relpermalink":"/publication/profiling-aerosol-liquid-water-content-using-a-polarization-lidar/","section":"publication","summary":"Aerosol liquid water content (ALWC) plays fundamental roles in atmospheric radiation and chemical processes. However, there is little information about ALWC vertical distribution due to the lack of sufficient measurement. In this study, a novel method to retrieve ALWC using a polarization lidar is proposed. By analyzing lidar measurement combined with in situ chemical composition measurements at the surface, the particle linear depolarization ratio δp is found to be well correlated with the liquid water mass fraction. The method is built upon a valid relationship between δp and the ratio of ALWC to the particle backscatter coefficient. ALWC can be retrieved with a relative error of 30% with this method. A case study shows that the ALWC in upper levels of the boundary layer may be different from that at the ground, suggesting the importance of measuring ALWC vertical profiles during haze episodes. The study proves that polarization lidars have the potential to retrieve vertical distributions of ALWC which will benefit studies on haze formation.","tags":[],"title":"Profiling Aerosol Liquid Water Content Using a Polarization Lidar","type":"publication"},{"authors":["Xianjun Xu","Zhongjing Jiang","Jing Li","Yiqi Chu","Wangshu Tan","Chengcai Li"],"categories":[],"content":"","date":1584201600,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1584201600,"objectID":"0ea1d7f0d5e4a8084af84f05e8e256e4","permalink":"https://tanwangshu.com/publication/impacts-of-meteorology-and-emission-control-on-the-abnormally-low-particulate-matter-concentration-observed-during-the-winter-of-2017/","publishdate":"2021-12-10T11:33:44+08:00","relpermalink":"/publication/impacts-of-meteorology-and-emission-control-on-the-abnormally-low-particulate-matter-concentration-observed-during-the-winter-of-2017/","section":"publication","summary":"As the capital of China, Beijing is the subject of great concern regarding atmospheric pollution, especially that of fine particulate matter (PM2.5). In winter 2017 (i.e., November 2017 to February 2018), PM2.5 concentration in Beijing decreased to its lowest value in the past ten years. In this study, we sought to investigate the impacts of meteorology and emission control on this abnormally low pollution phenomenon. Weather Research and Forecasting coupled with Chemistry (WRF-Chem) simulations show that sensitivity to meteorological factors accounts for approximately 51% of the observed change between winters 2016 and 2017 in Beijing. We further compared the pollution dispersion condition of winters 2016 and 2017 in terms of large-scale circulation patterns and local mixing layer heights (MLHs). The meteorological condition in 2017 was characterized by stronger wind speed (WS) and higher MLH. We classified circulation patterns into two types using the obliquely rotated Principal Component Analysis in T-mode (T-PCA) method. Active weather was found to be associated with high MLH, high near-surface WS, and high ventilation coefficient (VC), which favors the dispersion of pollutants. In contrast, the changes of meteorological variables and pollution conditions are almost opposite for stable weather. Active weather amounted to 73 and 85 days for winters 2016 and 2017, respectively. Stable weather conditions prevailed on 46 days in winter 2016, and 32 days in 2017. Less stable weather during winter 2017 compared with that of winter 2016 possibly favored efficient ventilation of boundary-layer pollution. A lack of persistent stable weather also contributed to low PM2.5 concentration in 2017. This research is important for air-pollution assessment and regional environmental management.","tags":[],"title":"Impacts of Meteorology and Emission Control on the Abnormally Low Particulate Matter Concentration Observed During the Winter of 2017","type":"publication"},{"authors":["Wangshu Tan","Chengcai Li","Yuechen Liu","Xiangxinyue Meng","Zhijun Wu","Ling Kang","Tong Zhu"],"categories":[],"content":"","date":1581350400,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1581350400,"objectID":"7c3d114ed5b8ee7a3ae6e0994e5bdf5f","permalink":"https://tanwangshu.com/publication/potential-of-polarization-lidar-to-profile-the-urban-aerosol-phase-state-during-haze-episodes/","publishdate":"2020-01-03T18:53:57+08:00","relpermalink":"/publication/potential-of-polarization-lidar-to-profile-the-urban-aerosol-phase-state-during-haze-episodes/","section":"publication","summary":"The phase states of atmospheric aerosol particles affect their physical, chemical, and optical properties. Particles with different phase states exhibit different viscosities and various shapes that cause differences in their scattering polarization. In this study, a novel method for inferring the phase state of submicrometer particles using the particle linear depolarization ratio (δp) retrieved from polarization lidar is proposed. The values of δp during several haze episodes showed good correlation with the in situ-measured rebound fraction and ambient relative humidity. Two case studies verify that polarization lidar has the potential to infer the phase state profiles of submicrometer particles and that the particle phase state in the upper boundary layer may differ from that near the ground during haze episodes.","tags":[],"title":"Potential of Polarization Lidar to Profile the Urban Aerosol Phase State During Haze Episodes","type":"publication"},{"authors":["Yiqi Chu","Jing Li","Chengcai Li","Wangshu Tan","Tianning Su","Jian Li"],"categories":[],"content":"","date":1569859200,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1569859200,"objectID":"28332f19976e7739e3469924ce95ebd4","permalink":"https://tanwangshu.com/publication/seasonal-and-diurnal-variability-of-planetary-boundary-layer-height-in-beijing-intercomparison-between-mpl-and-wrf-results/","publishdate":"2020-01-03T21:00:15+08:00","relpermalink":"/publication/seasonal-and-diurnal-variability-of-planetary-boundary-layer-height-in-beijing-intercomparison-between-mpl-and-wrf-results/","section":"publication","summary":"The Planetary boundary layer (PBL) plays an important role in energy exchange and pollutant dispersion. The height of the PBL (PBLH) usually exhibits distinct diurnal variation. In this study, we investigate the char- acteristics of PBLH variation of Beijing China based on 1-year observations from Micropulse LIDAR (MPL) data, and compared against the PBLH simulated by the Weather Research and Forecast (WRF) model using eight different schemes. The variation of daytime MPL PBLH has been classified into four representative types using k- means clustering technique. Through comparison against MPL, it is shown that the Mellor-Yamada Nakanishi and Niino Level 3 (MYNN3) scheme, a second-order closure scheme, performs the best in representing the PBLH variation in most of the cases. The non-local schemes also show advantages in convective situations, due to the stronger vertical mixing embedded in these schemes. Further analyses show that differences in PBLH definition is a major factor causing the divergence among different schemes, while the biases of the profiles play a minor role.","tags":[],"title":"Seasonal and Diurnal Variability of Planetary Boundary Layer Height in Beijing: Intercomparison Between MPL and WRF Results","type":"publication"},{"authors":["Wangshu Tan","Gang Zhao","Yingli Yu","Chengcai Li","Jian Li","Ling Kang","Tong Zhu","Chunsheng Zhao"],"categories":[],"content":"","date":1562860800,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1562860800,"objectID":"fda8166aa8a8107c055f90435e72af44","permalink":"https://tanwangshu.com/publication/method-to-retrieve-cloud-condensation-nuclei-number-concentrations-using-lidar-measurements/","publishdate":"2020-01-03T18:59:06+08:00","relpermalink":"/publication/method-to-retrieve-cloud-condensation-nuclei-number-concentrations-using-lidar-measurements/","section":"publication","summary":"A new method to retrieve CCN number concentrations using multiwavelength Raman lidars is proposed. The method implements hygroscopic enhancements of backscatter and extinction with relative humidity to represent particle hygroscopicity. The retrieved CCN number concentrations are in good agreement with theoretical calculated values. Sensitivity tests indicate that retrieval error in CCN arises mostly from uncertainties in extinction coefficients and RH profiles.","tags":[],"title":"Method to Retrieve Cloud Condensation Nuclei Number Concentrations Using Lidar Measurements","type":"publication"},{"authors":["Jian Li","Chengcai Li","Jianping Guo","Jing Li","Wangshu Tan","Ling Kang","Dandan Chen","Tao Song","Lin Liu"],"categories":[],"content":"","date":1550160000,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1550160000,"objectID":"dbca5e69d1f453717f2e5751cf78b861","permalink":"https://tanwangshu.com/publication/retrieval-of-aerosol-profiles-by-raman-lidar-with-dynamic-determination-of-the-lidar-equation-reference-height/","publishdate":"2020-01-03T21:01:20+08:00","relpermalink":"/publication/retrieval-of-aerosol-profiles-by-raman-lidar-with-dynamic-determination-of-the-lidar-equation-reference-height/","section":"publication","summary":"A reference height that often needs to be assumed in aerosol retrieval from Raman lidar tends to cause high uncertainty in retrieving the vertical distribution of aerosol optical properties. Here, a novel method is proposed to determine the height-revolved reference height, which is then used to retrieve aerosols from Raman lidar. This method can automatically avoid the atmospheric layers with the presence of aerosols, clouds and low signal to noise ratio (SNR). Based on elastic (at 355 nm) and inelastic (at 387 nm) signals collected during the period from 5 December 2016 to 5 March 2017 by a ground-based Raman lidar in Beijing, China, the aerosol optical properties, such as extinction coefficient, backscattering coefficient and lidar ratio have been successfully re- trieved. Results show that the averaged nighttime aerosol optic depth (AOD) from Raman lidar is in good agreement with early morning AOD retrieved from a collocated sunphotometer. The AOD exhibits a strong diurnal variation with a peak at 1500 Beijing time. On average, the nighttime AOD at 355 nm is 0.32, whereas the daytime AOD is 0.72 over Beijing during the study period. The column averaged lidar ratio is 44 sr at 355 nm, roughly consistent with previous studies. Our findings shed light on the pathways towards improving the retrieval of vertical distribution of aerosols optical properties during nighttime.","tags":[],"title":"Retrieval of Aerosol Profiles by Raman Lidar With Dynamic Determination of the Lidar Equation Reference Height","type":"publication"},{"authors":["Yuxuan Bian","Chunsheng Zhao","Wanyun Xu","Ye Kuang","Jiangchuan Tao","Wei Wei","Nan Ma","Gang Zhao","Shaopeng Lian","Wangshu Tan","John E. Barnes"],"categories":[],"content":"","date":1529067754,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1529067754,"objectID":"6c3255f60fb72324b383338d0316399f","permalink":"https://tanwangshu.com/publication/a-novel-method-to-retrieve-the-nocturnal-boundary-layer-structure-based-on-ccd-laser-aerosol-detection-system-measurements/","publishdate":"2020-01-03T21:02:34+08:00","relpermalink":"/publication/a-novel-method-to-retrieve-the-nocturnal-boundary-layer-structure-based-on-ccd-laser-aerosol-detection-system-measurements/","section":"publication","summary":"Mixing layer height (MLH) is a key parameter for evaluating the transport and diffusion of atmospheric pollu- tants in both air quality forecasting and satellite data retrieval. However, there is a lack of methods for obtaining the nocturnal MLH. In this study, a novel instrument named the charge-coupled device-laser aerosol detection system (CCD-LADS) was developed to study the nocturnal MLH and boundary layer structure from the surface. The system mainly includes a continuous laser and a charge-coupled device camera with a fisheye lens. Structures of atmospheric layers characterized by the CCD-LADS were compared with those measured by a ceilometer. The heights of two atmospheric layers quantified by measurements with the CCD-LADS and the ceilometer show good agreement, with a relative difference of 5%. The results of this comparison demonstrated that the CCD-LADS is capable of distinctly identifying the nocturnal vertical structure of the atmosphere. The advantage of the CCD-LADS in retrieving the nocturnal MLH is that the CCD-LADS can provide the boundary layer structures under 100 m, while the ceilometer and other lidar measurements cannot retrieve the atmo- spheric structures below that altitude. CCD-LADS was deployed in a comprehensive field campaign measuring air pollution in the University of Chinese Academy of Sciences, located at the border between the North China Plain and Yanshan Mountain, during January 2016. The fine characteristics and patterns of the nocturnal boundary layer structures were derived with the CCD-LADS measurements.","tags":[],"title":"A Novel Method to Retrieve the Nocturnal Boundary Layer Structure Based on CCD Laser Aerosol Detection System Measurements","type":"publication"},{"authors":["Gang Zhao","Chunsheng Zhao","Ye Kuang","Jiangchuan Tao","Wangshu Tan","Yuxuan Bian","Jing Li","Chengcai Li"],"categories":[],"content":"","date":1507813463,"expirydate":-62135596800,"kind":"page","lang":"en","lastmod":1507813463,"objectID":"cdf084d3d4177c86ce885c9e4b399725","permalink":"https://tanwangshu.com/publication/impact-of-aerosol-hygroscopic-growth-on-retrieving-aerosol-extinction-coefficient-profiles-from-elastic-backscatter-lidar-signals/","publishdate":"2020-01-03T21:04:23+08:00","relpermalink":"/publication/impact-of-aerosol-hygroscopic-growth-on-retrieving-aerosol-extinction-coefficient-profiles-from-elastic-backscatter-lidar-signals/","section":"publication","summary":"In this paper, influences of aerosol hygroscopic growth on the lidar ratio are studied. Results indicate that both the magnitude and vertical structures of the retrieved aerosol extinction coefficient (σext) profile from lidar signals are significantly biased. This study proposes a feasible method for reducing the bias of retrieving the σext profile and this method can be implemented in operational retrieval of the aerosol σext profile and for pollution monitoring.","tags":[],"title":"Impact of Aerosol Hygroscopic Growth on Retrieving Aerosol Extinction Coefficient Profiles From Elastic-backscatter Lidar Signals","type":"publication"}]