地球信息科学学报
地毬信息科學學報
지구신식과학학보
GEO-INFORMATION SCIENCE
2014年
5期
790-796
,共7页
POLDER%AERONET%偏振遥感%气溶胶%粒子尺度
POLDER%AERONET%偏振遙感%氣溶膠%粒子呎度
POLDER%AERONET%편진요감%기용효%입자척도
POLDER%AERONET%polarized remote sensing%aerosol%particle size
目前,偏振遥感已被用于气溶胶卫星和地基遥感中,其仅对小粒子敏感。本研究以2007-2008年间的POL-DER(Polarization and Directionality of the Earth’s Reflectances)和AERONET(Aerosol Robotic Network)合肥站的气溶胶数据为研究对象,探讨了偏振遥感对气溶胶粒子尺度的敏感性。利用AERONET合肥站的尺度分布数据和折射指数数据,计算了不同尺度范围内气溶胶粒子的光学厚度,并与对应的POLDER反演结果作拟合,通过寻找最佳拟合对应的尺度范围确定偏振遥感敏感的粒子尺度。结果表明,偏振遥感并非对所有尺度的小模式气溶胶粒子都敏感,在865 nm波段,其敏感的气溶胶粒子上限半径约为0.3μm左右。这一结果对指导气溶胶偏振遥感,以及理解和应用偏振遥感气溶胶产品等具有重要意义。
目前,偏振遙感已被用于氣溶膠衛星和地基遙感中,其僅對小粒子敏感。本研究以2007-2008年間的POL-DER(Polarization and Directionality of the Earth’s Reflectances)和AERONET(Aerosol Robotic Network)閤肥站的氣溶膠數據為研究對象,探討瞭偏振遙感對氣溶膠粒子呎度的敏感性。利用AERONET閤肥站的呎度分佈數據和摺射指數數據,計算瞭不同呎度範圍內氣溶膠粒子的光學厚度,併與對應的POLDER反縯結果作擬閤,通過尋找最佳擬閤對應的呎度範圍確定偏振遙感敏感的粒子呎度。結果錶明,偏振遙感併非對所有呎度的小模式氣溶膠粒子都敏感,在865 nm波段,其敏感的氣溶膠粒子上限半徑約為0.3μm左右。這一結果對指導氣溶膠偏振遙感,以及理解和應用偏振遙感氣溶膠產品等具有重要意義。
목전,편진요감이피용우기용효위성화지기요감중,기부대소입자민감。본연구이2007-2008년간적POL-DER(Polarization and Directionality of the Earth’s Reflectances)화AERONET(Aerosol Robotic Network)합비참적기용효수거위연구대상,탐토료편진요감대기용효입자척도적민감성。이용AERONET합비참적척도분포수거화절사지수수거,계산료불동척도범위내기용효입자적광학후도,병여대응적POLDER반연결과작의합,통과심조최가의합대응적척도범위학정편진요감민감적입자척도。결과표명,편진요감병비대소유척도적소모식기용효입자도민감,재865 nm파단,기민감적기용효입자상한반경약위0.3μm좌우。저일결과대지도기용효편진요감,이급리해화응용편진요감기용효산품등구유중요의의。
One of the polarized remote sensing advantages is its insensitivity to the land surface reflection, and now it has been widely used for aerosol properties retrieval from satellite and ground-based remote sensing. As to aerosols, the polarized remote sensing is only sensitive to small particles;however, there are different under-standings of the small particle size to which extend the polarized remote sensing is sensitive. For example, some studies take fine mode aerosols as small particles, but the maximum radius of fine mode aerosol varies between 0.4~1.0 μm . What’s the upper threshold of the particle size to which the polarized remote sensing is sensitive? In order to determine the sensitivity of the polarized remote sensing to aerosol particle size, three steps are con-ducted as follows: firstly, the POLDER (Polarization and Directionality of the Earth’s Reflectances, which is equipped on Polarization and Anisotropy of Reflectances for Atmospheric Science coupled with Observations from a Lidar) and AERONET (Aerosol Robotic Network) data in Hefei between 2007 and 2008 are collected and processed, i.e. the AERONET data within a 1-hour range window (±30min) around the POLDER during ze-nith pass and the POLDER data in a 3×3 pixel box centered on the Hefei site are averaged in time and space re-spectively. Secondly, the aerosol optical depths in different particle size range are calculated using the refractive index and size distribution data from Hefei site according to Mie theory. Finally, the particle size to which the po-larized remote sensing is sensitive is determined by finding the best fit between the POLDER aerosol optical depth and the AERONET aerosol optical depth calculated above. The results show that the polarized remote sens-ing is not sensitive to all the fine mode particles, but sensitive to particles with radius approximately less than 0.3μm at 865nm band. The results will not only help us to understand and utilize the aerosol products obtained from the polarized remote sensing, but also help us in polarized remote sensing application.