Estimation of the influence of snow grain size and black carbon on albedo is essential in obtaining the accurate albedo. In this paper, field measurement data, including snow grain size, snow depth and density was obt...Estimation of the influence of snow grain size and black carbon on albedo is essential in obtaining the accurate albedo. In this paper, field measurement data, including snow grain size, snow depth and density was obtained. Black carbon samples were collected from the snow surface. A simultaneous observation using Analytical Spectral Devices was employed in the Qiyi Glacier located in the Qilian Mountain. Analytical Spectral Devices spectrum data were used to analyze spectral re- flectance of snow for different grain size and black carbon content. The measurements were compared with the results obtained from the Snow, Ice, and Aerosol Radiation model, and the simulation was found to correlate well with the ob- served data. However, the simulated albedo was near to 0.98 times of the measured albedo, so the other factors were as- sumed to be constant using the corrected Snow, Ice, and Aerosol Radiation model to estimate the influence of measured snow grain size and black carbon on albedo. Field measurements were controlled to fit the relationship between the snow grain size and black carbon in order to estimate the influence of these factors on the snow albedo.展开更多
In this paper, the significance and history of studying snow grain size is introduced. Based on the assumption that high reflectivity in the visible band and significant decreasing reflectivity of snow surface in the ...In this paper, the significance and history of studying snow grain size is introduced. Based on the assumption that high reflectivity in the visible band and significant decreasing reflectivity of snow surface in the infrared band, the grain size of snow, spherical and non-spherical, is sensitive to changes in remote sensing retrieval foundation. Also, models and algorithms applied in current studies are reviewed, together with their advantages and disadvantages. In addition, in order to obtain retrieval accuracy, some factors that may affect grain size are also discussed, such as temperature, wavelength, arid particle shape, as well as method authentication.展开更多
A comprehensive analysis of sea ice and its snow cover during the summer in the Arctic Pacific sector was conducted using the observations recorded during the 7th Chinese National Arctic Research Expedition(CHIANRE-20...A comprehensive analysis of sea ice and its snow cover during the summer in the Arctic Pacific sector was conducted using the observations recorded during the 7th Chinese National Arctic Research Expedition(CHIANRE-2016)and the satellite-derived parameters of the melt pond fraction(MPF)and snow grain size(SGS)from MODIS data.The results show that there were many low-concentration ice areas in the south of 78°N,while the ice concentration and thickness increased significantly with the latitude above the north of 78°N during CHIANRE-2016.The average MPF presented a trend of increasing in June and then decreasing in early September for 2016.The average snow depth on sea ice increased with latitude in the Arctic Pacific sector.We found a widely developed depth hoar layer in the snow stratigraphic profiles.The average SGS generally increased from June to early August and then decreased from August to September in 2016,and two valley values appeared during this period due to snowfall incidents.展开更多
双向反射分布函数(BRDF,Bidirectional Reflectance Distribution Function)反演作为定量遥感的重要研究方向,其定量化地描述了地表反射的各向异性特点.传统的积雪BRDF反演主要采用ROSS+LI核,采用贝叶斯概率统计的方法或者采用最小二乘...双向反射分布函数(BRDF,Bidirectional Reflectance Distribution Function)反演作为定量遥感的重要研究方向,其定量化地描述了地表反射的各向异性特点.传统的积雪BRDF反演主要采用ROSS+LI核,采用贝叶斯概率统计的方法或者采用最小二乘的方法进行求解系数,方法简单可行,但是这些模型对积雪的物理特性定量描述不是太全面.积雪是一个复杂的体系,众多因素对BRDF影响较大,如雪粒径与雪污化物,传统的ROSS+LI核不能定量地描述这些因素对积雪的BRDF的影响.渐进辐射传输算法,以其计算简单,运算速度快而不降低辐射传输的精度,被广泛地运用到定量遥感之中.利用此理论进行积雪BRDF反演及验证,首先进行积雪的雪粒径反演,采用了渐进辐射传输模型建立光谱库;其后确定中心波长1.03μm作为最佳雪粒径反演波段,同时采用此理论反演了雪污染量;最后利用已有的雪粒径与反演的相对污化物含量进行BRDF重构.实验表明:基于渐进辐射传输的积雪BRDF具有可行性,精度能够满足生产之用,同时产生的中间产品,如雪粒径、雪污染等,可以广泛地运用于生产实践之中.通过此方法能够有效地将积雪遥感的雪粒径、雪污染、BRDF串联起来,方便积雪快速定量化描述.展开更多
应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球...应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球形的雪粒,球形雪粒的积雪反照率更低;吸光性颗粒物对光谱反照率的影响主要在可见光和紫外波段。此外,雪粒径的增大能使吸光性颗粒物的光吸收效应增强。结合东北地区的实测数据,我们发现SAMDS模拟的积雪宽波段反照率与实测结果较为一致。同时,SAMDS模式模拟结果表明,在东北地区,积雪中0. 1～1μg·g^(-1)的黑碳浓度导致积雪宽波段反照率减少2%～8%,造成的瞬时辐射强迫为9～35 W·m^(-2)。展开更多
基金supported by "Strategic Priority Research Program (B)" of the Chinese Academy of Sciences (Grant No. XDB03030204)SKLCS (No. SKLCS-OP-2014-03)Major Research of National Natural Science Foundation of China (Grant No. 41190084)
文摘Estimation of the influence of snow grain size and black carbon on albedo is essential in obtaining the accurate albedo. In this paper, field measurement data, including snow grain size, snow depth and density was obtained. Black carbon samples were collected from the snow surface. A simultaneous observation using Analytical Spectral Devices was employed in the Qiyi Glacier located in the Qilian Mountain. Analytical Spectral Devices spectrum data were used to analyze spectral re- flectance of snow for different grain size and black carbon content. The measurements were compared with the results obtained from the Snow, Ice, and Aerosol Radiation model, and the simulation was found to correlate well with the ob- served data. However, the simulated albedo was near to 0.98 times of the measured albedo, so the other factors were as- sumed to be constant using the corrected Snow, Ice, and Aerosol Radiation model to estimate the influence of measured snow grain size and black carbon on albedo. Field measurements were controlled to fit the relationship between the snow grain size and black carbon in order to estimate the influence of these factors on the snow albedo.
基金provided by National Science Fundamental Key Project(40930526,40901041)Science Research Program of Global Change Research of China(Grant No.2010CB951404)
文摘In this paper, the significance and history of studying snow grain size is introduced. Based on the assumption that high reflectivity in the visible band and significant decreasing reflectivity of snow surface in the infrared band, the grain size of snow, spherical and non-spherical, is sensitive to changes in remote sensing retrieval foundation. Also, models and algorithms applied in current studies are reviewed, together with their advantages and disadvantages. In addition, in order to obtain retrieval accuracy, some factors that may affect grain size are also discussed, such as temperature, wavelength, arid particle shape, as well as method authentication.
基金The National Key Research and Development Program of China under contract No.2016YFC1402704the National Natural Science Foundation of China under contract No.42076235the Special Fund for High Resolution Images Surveying and Mapping Application System under contract No.42-Y30B04-9001-19/21
文摘A comprehensive analysis of sea ice and its snow cover during the summer in the Arctic Pacific sector was conducted using the observations recorded during the 7th Chinese National Arctic Research Expedition(CHIANRE-2016)and the satellite-derived parameters of the melt pond fraction(MPF)and snow grain size(SGS)from MODIS data.The results show that there were many low-concentration ice areas in the south of 78°N,while the ice concentration and thickness increased significantly with the latitude above the north of 78°N during CHIANRE-2016.The average MPF presented a trend of increasing in June and then decreasing in early September for 2016.The average snow depth on sea ice increased with latitude in the Arctic Pacific sector.We found a widely developed depth hoar layer in the snow stratigraphic profiles.The average SGS generally increased from June to early August and then decreased from August to September in 2016,and two valley values appeared during this period due to snowfall incidents.
文摘双向反射分布函数(BRDF,Bidirectional Reflectance Distribution Function)反演作为定量遥感的重要研究方向,其定量化地描述了地表反射的各向异性特点.传统的积雪BRDF反演主要采用ROSS+LI核,采用贝叶斯概率统计的方法或者采用最小二乘的方法进行求解系数,方法简单可行,但是这些模型对积雪的物理特性定量描述不是太全面.积雪是一个复杂的体系,众多因素对BRDF影响较大,如雪粒径与雪污化物,传统的ROSS+LI核不能定量地描述这些因素对积雪的BRDF的影响.渐进辐射传输算法,以其计算简单,运算速度快而不降低辐射传输的精度,被广泛地运用到定量遥感之中.利用此理论进行积雪BRDF反演及验证,首先进行积雪的雪粒径反演,采用了渐进辐射传输模型建立光谱库;其后确定中心波长1.03μm作为最佳雪粒径反演波段,同时采用此理论反演了雪污染量;最后利用已有的雪粒径与反演的相对污化物含量进行BRDF重构.实验表明:基于渐进辐射传输的积雪BRDF具有可行性,精度能够满足生产之用,同时产生的中间产品,如雪粒径、雪污染等,可以广泛地运用于生产实践之中.通过此方法能够有效地将积雪遥感的雪粒径、雪污染、BRDF串联起来,方便积雪快速定量化描述.
文摘应用了一种新的模式spectral albedo model for dirty snow,简称SAMDS,研究了不同参数对于积雪反照率的影响,结果表明:在天顶角固定为60°的条件下,新雪的粒径从50μm增大到800μm,使其宽波段反照率从0. 92减小到0. 78;相对于非球形的雪粒,球形雪粒的积雪反照率更低;吸光性颗粒物对光谱反照率的影响主要在可见光和紫外波段。此外,雪粒径的增大能使吸光性颗粒物的光吸收效应增强。结合东北地区的实测数据,我们发现SAMDS模拟的积雪宽波段反照率与实测结果较为一致。同时,SAMDS模式模拟结果表明,在东北地区,积雪中0. 1～1μg·g^(-1)的黑碳浓度导致积雪宽波段反照率减少2%～8%,造成的瞬时辐射强迫为9～35 W·m^(-2)。
