This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surf...This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surface to 10km and from 2008 to 2011 based on LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies). Aerosol extinction (AE), aerosol backscatter (AB), and aerosol depolarization (AD) generally increase from the surface to 1.2 km and decrease from 1.2 km to the upper layers in both WNA and CSA. AE and AB in CSA (maximum of 0.13 km<sup>-1</sup>, 0.14 km<sup>-1</sup>, 0.0021 km<sup>-1</sup>‧sr<sup>-1</sup>, 0.0033 km<sup>-1</sup>‧sr<sup>-1</sup>) are higher than in WNA (maximum of 0.07 km<sup>-1</sup>, 0.08 km<sup>-1</sup>, 0.0017 km<sup>-1</sup>‧sr<sup>-1</sup>, 0.0015 km<sup>-1</sup>‧sr<sup>-1</sup>) at 532 and 1064 nm respectively. AD in WNA (maximum of 0.25) is significantly higher than in CSA (maximum of 0.05). There is a smooth change with the height of cloud extinction and backscatter in WNA and CSA, while there is a remarkable increase of cloud depolarization with height, whereby it is high in CSA and low in WNA due to high and low fraction of cirrus respectively. Altocumulus has the highest extinction in NA (0.0139 km<sup>-1</sup>), CA (0.058 km<sup>-1</sup>), WA (0.013 km<sup>-1</sup>), while low overcast transparent (0.76 km<sup>-1</sup>) below 1 km in SA. The major findings of this study may contribute to the improvement of our understanding of aerosol-cloud interaction studies in dominated dust and smoke aerosol regions.展开更多
【目的】中国传统园林空间复杂多变,传统的分析方法难以深入探索传统园林复杂的三维视觉空间特征。三维激光雷达(light detection and ranging,LiDAR)点云技术在传统园林空间研究方面具有精度高、信息全等优势,借助LiDAR点云技术深入探...【目的】中国传统园林空间复杂多变,传统的分析方法难以深入探索传统园林复杂的三维视觉空间特征。三维激光雷达(light detection and ranging,LiDAR)点云技术在传统园林空间研究方面具有精度高、信息全等优势,借助LiDAR点云技术深入探索中国传统园林视觉空间特征,可为现代人居环境空间营造提供借鉴与参考。【方法】基于LiDAR点云技术提出一套适用于中国传统园林视觉空间分析的方法,并以三维可视性、视野舒展度及景物视野占比3项指标量化描述视觉空间。【结果】以寄畅园为例,构建了寄畅园LiDAR点云体素模型,利用提出的方法对锦汇漪西侧滨水步道11个视点的视觉空间进行了量化分析,解析了寄畅园的视觉空间特征,并探究了该步道的空间感知序列。【结论】证实了利用LiDAR点云技术展开传统园林视觉空间研究的可行性与准确性,提出的方法可应用于其他传统园林视觉空间的分析研究中。展开更多
文摘This study evaluates the vertical profiles of aerosol and cloud optical properties in 40 dominated dust and smoke regions in Western-Northern Africa (WNA) and Central-Southern Africa (CSA), respectively, from the surface to 10km and from 2008 to 2011 based on LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies). Aerosol extinction (AE), aerosol backscatter (AB), and aerosol depolarization (AD) generally increase from the surface to 1.2 km and decrease from 1.2 km to the upper layers in both WNA and CSA. AE and AB in CSA (maximum of 0.13 km<sup>-1</sup>, 0.14 km<sup>-1</sup>, 0.0021 km<sup>-1</sup>‧sr<sup>-1</sup>, 0.0033 km<sup>-1</sup>‧sr<sup>-1</sup>) are higher than in WNA (maximum of 0.07 km<sup>-1</sup>, 0.08 km<sup>-1</sup>, 0.0017 km<sup>-1</sup>‧sr<sup>-1</sup>, 0.0015 km<sup>-1</sup>‧sr<sup>-1</sup>) at 532 and 1064 nm respectively. AD in WNA (maximum of 0.25) is significantly higher than in CSA (maximum of 0.05). There is a smooth change with the height of cloud extinction and backscatter in WNA and CSA, while there is a remarkable increase of cloud depolarization with height, whereby it is high in CSA and low in WNA due to high and low fraction of cirrus respectively. Altocumulus has the highest extinction in NA (0.0139 km<sup>-1</sup>), CA (0.058 km<sup>-1</sup>), WA (0.013 km<sup>-1</sup>), while low overcast transparent (0.76 km<sup>-1</sup>) below 1 km in SA. The major findings of this study may contribute to the improvement of our understanding of aerosol-cloud interaction studies in dominated dust and smoke aerosol regions.
文摘【目的】中国传统园林空间复杂多变,传统的分析方法难以深入探索传统园林复杂的三维视觉空间特征。三维激光雷达(light detection and ranging,LiDAR)点云技术在传统园林空间研究方面具有精度高、信息全等优势,借助LiDAR点云技术深入探索中国传统园林视觉空间特征,可为现代人居环境空间营造提供借鉴与参考。【方法】基于LiDAR点云技术提出一套适用于中国传统园林视觉空间分析的方法,并以三维可视性、视野舒展度及景物视野占比3项指标量化描述视觉空间。【结果】以寄畅园为例,构建了寄畅园LiDAR点云体素模型,利用提出的方法对锦汇漪西侧滨水步道11个视点的视觉空间进行了量化分析,解析了寄畅园的视觉空间特征,并探究了该步道的空间感知序列。【结论】证实了利用LiDAR点云技术展开传统园林视觉空间研究的可行性与准确性,提出的方法可应用于其他传统园林视觉空间的分析研究中。
