利用MODIS和MISR资料对APEC会议期间气溶胶时空分布特征的分析

利用卫星遥感的MODIS和MISR数据,对比分析了2014年亚太经合组织（APEC）会议期间（11月3日~12日）及其前后一个月的气溶胶时空分布特征。分析发现APEC会议期间的气溶胶光学厚度（aerosol optical depth, AOD）相比APEC会议前期,在京津冀地区有明显减小,MODIS（MISR）数据显示在京津冀地区AOD减小了38.7%（36.4%）,在北京地区减小更多,减小了64.6%（39.9%）。Angstrom指数在京津冀地区的廊坊、保定、衡水等大部分城市,APEC会议期间的Angstrom指数相对前期较小,说明其在APEC会议期间气溶胶粒子的有效半径相对较大。APEC会议期间的细模态气溶胶光学厚度相比APEC会议前期也有所减小,且在北京地区细模态气溶胶光学厚度的下降幅度要大于粗模态气溶胶的下降幅度。     

基于主成分分析的CO2统计反演方法

二氧化碳（CO2）卫星遥感中,大气环境因素是影响反演精度的重要原因,目前反演条件通常限制在气溶胶光学厚度小于0.3的情况。我国大气气溶胶高值情况较为普遍,对大气条件的较高要求将严重影响我国CO2卫星遥感数据的应用能力。针对这种情况,利用基于主成分分析法对中国京津地区高气溶胶光学厚度的大气CO2反演,得到的CO2柱浓度与2013年、2014年GOSAT-Level2产品进行对比分析,均方根误差分别为0.65%和0.46%,相关性分别为0.77和0.93。     

基于多源数据的PM2.5反演方法

利用MODIS L1B 1km分辨率数据和NASA 的V5.2 气溶胶改良业务反演算法,对南京都市圈2013年9月至2014年1月期间的气溶胶光学厚度（AOD）进行反演,并运用AERONET地基气溶胶监测网的AOD产品对反演结果进行验证。然后,将经过验证后的AOD与国家环保部建立的国家空气质量自动监测点实测得到的PM2.5质量浓度和PM10质量浓度根据经典统计学进行线性回归性分析,并用气溶胶细模态光学厚度AODf和气象因子对PM2.5质量浓度与MODIS AOD之间的模型进行修正,修正后的模型为y=136.78+9.16x1-0.36 x2-3.98x3,R2=0.79,并应用该模型,证实气溶胶光学厚度可以用来对城市空气质量进行评价。     

北京奥运期间的碳黑气溶胶观测研究

2008年7～8月在北京市奥体中心的遥感所站点连续实时监测碳黑气溶胶(BC),研究其在北京奥运期间的变化特征和来源.奥运会前BC平均质量浓度约为4.58μg/m3,而奥运会期间其平均浓度约为3.07μg/m3,下降比约为33.0%,这说明减排措施有效降低了BC的排放总量.同步监测的可吸入颗粒物(PM10)与BC一致性较好,相关系数为0.86,BC约占PM10的1.9%.比对2007年同期BC浓度数据,也证实了北京地区在实行各项减排措施后,BC的污染情况有较大好转.     

航空多角度偏振观测京津唐地区大气气溶胶

航空大气多角度偏振辐射计（AMPR）可以获取多角度、多波段和偏振辐射观测数据,将AMPR装载于遥感飞机对京津唐地区（工业发达、人口集中）的气溶胶进行观测,经过数据处理和反演,得到该地区的气溶胶光学厚度。反演过程中,以大气校正后的1640nm波段观测数据作为下垫面的地表偏振信息,结合查找表的方法,综合利用多角度光谱偏振辐射信息,反演得到气溶胶的光学厚度。反演结果与同步地基观测数据对比,结果表明AMPR具备观测典型区域大气气溶胶的能力。     

一种MODIS遥感图像大气校正的快速算法

本文设计了基于大气辐射传输模型对MODIS遥感图像进行大气校正的一种新的快速算法。根据Kaufman气溶胶光学厚度反演方法的基本原理,建立了简化的气溶胶光学厚度反演模型,通过6S模型获取气溶胶光学厚度参数,利用经验公式计算大气反射率及大气透过率等参数,实现了MODIS遥感图像的快速大气校正。     

FY-3A/MERSI气溶胶光学厚度资料在北京及其周围地区的精度评价

采用波长插值和时空匹配的方法,对气溶胶自动观测网（aerosol robotic network, AERONET）和风云三号卫星中分辨率光谱成像仪（FY3A-MERSI） 气溶胶光学厚度（aerosol optical depth, AOD）产品进行匹配,并进一步使用AERONET AOD数据对北京以及周围地区的FY-3A/MERSI AOD产品精度进行验证分析。实验结果表明：⑴FY-3A AOD与AERONET AOD具有较高的相关性（R=0.733）,总体偏低于AERONET AOD(bias=-0.012);⑵下垫面植被覆盖度越高,FY-3A AOD反演精度越高;气溶胶浓度较低精度越高,反之反演精度越低;并且在春冬季节的反演精度高于夏秋季节。此结论可为北方地区的FY-3A/MERSI气溶胶产品使用提供参考。     

APEC期间京津冀地区污染物变化特征分析

利用中国环境监测总站发布的2013年11月1日~2014年12月12日污染物实时浓度数据,分析了京津冀地区污染物变化特征。结果显示：PM2.5、PM10、SO2、NO2和CO浓度年平均值分别为95.3, 163.9, 54.7, 48.9 μg/m3, 1.5 mg/m3;五种污染物浓度都表现出冬季高夏季低的季节变化特征,但不同污染物在不同的月份又有其特殊的变化特征。APEC期间京津冀地区PM2.5、PM10、SO2、NO2和CO平均浓度分别为66.1, 123.7, 33.2,、48.5 μg/m3, 1.2 mg/m3。APEC期间京津冀地区PM2.5浓度是APEC前后一个月的60.1%、59.4%;APEC期间气态污染物CO、SO2、NO2浓度与APEC前一个月相当,但APEC后急剧增加。减排措施使京津冀地区PM2.5浓度削减40%左右,PM10削减35%左右,NO2削减10%左右,CO削减15%左右。     

大气气溶胶光学厚度反演软件系统设计和实现

为了实现大气气溶胶光学厚度反演的要求,提出一种基于传统暗像元算法为基础的一体化软件系统设计方案,并完成系统的设计和气溶胶光学厚度反演实验。该系统的软件设计主要利用开源GDAL库对MODIS遥感数据进行提取和处理,并通过6S模型建立得出数据查算表。经过应用表明通过该软件系统使反演过程简单化、可视化,同时实现了气溶胶光学厚度反演的一体化的处理。     

基于MAX-DOAS的对流层NO2和气溶胶光学厚度遥测反演

随着全球工业化速度加快和人口的增多,大气环境问题日益突出,NO2和气溶胶在大气化学中扮演着重要的角色。地基多轴差分吸收光谱技术（MAX-DOAS）基于被动DOAS原理,近年来已成功应用于大气痕量气体柱浓度和气溶胶光学厚度（AOD）测量方面。本文基于被动DOAS算法对合肥秸秆燃烧期间NO2柱浓度以及气溶胶光学厚度进行了观测,并把对流层柱浓度和臭氧监测仪(Ozone Monitoring Instrument, OMI)结果进行对比;测量的气溶胶光学厚度和太阳光度计（CE318）进行了对比。结果表明,MAX-DOAS测量结果要高于卫星值,11月6日MAX-DOAS测量NO2柱浓度日均值为OMI的1.9倍;二者在无云条件下一致性较好;MAX-DOAS反演AOD和太阳光度计结果相关性在0.9以上。     

Retrieval of optical depth and particle size distribution oftropospheric and stratospheric aerosols by means of Sun photometry

Aerosol optical depth measurements by means of ground-based Sun photometry were made in Bern, Switzerland during two and a half years primarily to provide quantitative corrections for atmospheric effects in remotely sensed data in the visible and near-infrared spectral region. An investigation of the spatial variability of tropospheric aerosol was accomplished in the summer of 1994 in the Swiss Central Plain, a region often covered by a thick aerosol layer. Intercomparisons are made with two Sun photometers operated by the Swiss Meteorological Institute in Payerne (Swiss Central Plain) and Davos (Swiss Alps, 1590 m a.s.l.). By means of an inversion technique, columnar particle size distributions were derived from the aerosol optical depth spectra. Effective radius, columnar surface area, and columnar mass were computed from the inversion results. Most of the spectra measured in Bern exhibit an Angstrom-law dependence. Consequently, the inverted size distributions are very close to power-law distributions. Data collected during a four month calibration campaign in fall 1993 at a high-mountain station in the Swiss Alps (Jungfraujoch, 3580 m) allowed the authors to study optical properties of stratospheric aerosol. The extinction spectra measured have shown to be still strongly influenced by remaining aerosol of the June 1991 volcanic eruptions of Mount Pinatubo. Inverted particle size distributions can be characterized by a broad monodisperse peak with a mode radius around 0.25 μm. Both aerosol optical depths and effective radii had not yet returned to pre-eruption values. Comparison of retrieved aerosol optical depth, columnar surface area and mass, with the values derived from lidar observations performed in Garmisch-Partenkirchen, Southern-Germany, yielded good agreement     

宝鸡市一次污染过程黑碳气溶胶的变化特征及潜在源解析

利用AE-31型黑碳仪于2019年2月4-26日对宝鸡市的黑碳(BC)气溶胶进行了在线连续监测,并结合PM2.5质量浓度、风速风向等数据,采用聚类分析研究了该地区污染期间BC质量浓度的变化及来源.结果表明,观测期间BC平均质量浓度为2.8μg·m-3,范围为0.4～8.0μg·m-3;PM2.5平均质量浓度为119.9...     

Remote sensing of cloud, aerosol, and water vapor properties fromthe moderate resolution imaging spectrometer (MODIS)

The authors describe the status of MODIS-N and its companion instrument MODIS-T (tilt), a tiltable cross-track scanning spectrometer with 32 uniformly spaced channels between 0.410 and 0.875 μm. They review the various methods being developed for the remote sensing of atmospheric properties using MODIS, placing primary emphasis on the principal atmospheric applications of determining the optical, microphysical, and physical properties of clouds and aerosol particles from spectral reflection and thermal emission measurements. In addition to cloud and aerosol properties, MODIS-N will be used for determining the total precipitable water vapor and atmospheric stability. The physical principles behind the determination of each of these atmospheric products are described, together with an example of their application to aircraft and/or satellite measurements     

Dy-doped chlorides as gain media for 1.3 μm telecommunicationsamplifiers

We propose that Dy³⁺-doped chloride crystals be considered as candidates for amplification of the 1.3 μm signal used by the telecommunications network. While several of these types of crystals can provide gain at the specified operating wavelength of 1.31 μm, and furthermore offer adequate bandwidth, we have focused our attention on LaCl₃:Dy as an illustrative case to explore in greater depth. Spectroscopic measurements were made on un-oriented samples of this material; excited-state lifetimes and LaCl₃:Dy³⁺ Judd-Ofelt parameters are reported. Wavelength-resolved absorption and emission cross sections are presented for the 1.3 μm W&rlhar2;Z band. Pump-probe measurements (using 0.92 μm and 1.32 μm, respectively) prove that the observed gain properties of LaCl₃:Dy are consistent with those predicted on the basis of the spectroscopic cross sections. The Dy:chloride gain media appear to have fundamental optical characteristics amenable to superior 1.3 μm telecom amplifier performance, although many fabrication issues would have to be addressed to produce a practical amplifier     

Detection of forests using mid-IR reflectance: an application foraerosol studies

The detection of dark, dense vegetation is an important step in the remote sensing of aerosol loading. Current methods that employ the red (0.64 μm) and the near-IR (0.84 μm) regions are unsatisfactory in that the presence of aerosols in the scene distorts the apparent reflectance in the visible and near-IR ranges of the spectrum. The mid-IR spectral region is also sensitive to vegetation due to the absorption of liquid water in the foliage, but is not sensitive to the presence of most aerosols (except for dust). Therefore, mid-IR channels on the AVHRR and EOS-MODIS (e.g., the 3.75 μm or the 3.95 μm channels) have a unique potential for the remote sensing of dark, dense vegetation, particularly in the presence of biomass burning smoke or industrial/urban haze. The reflective part of the 3.75 μm channel (ρ_3.75) is applied to images of the AVHRR over the eastern United States. This channel was found to be correlated to reflectance at 0.64 μm (ρ_0.64), less sensitive to haze than the visible channel and superior to both the 0.64 μm reflectance and the normalized difference vegetation index (NDVI) to determine forest pixels in an image. However, its application to monitor the seasonal evolution of vegetation is presently questionable. For the purpose of the remote sensing of aerosol over dark, dense vegetation, it is proposed that the dark, dense vegetation be determined from ρ_3.75<0.025. These findings may have further implications for other specific applications of the remote sensing of vegetation in hazy atmospheres     

北京2014年冬季边界层高度与颗粒物浓度的相关性研究

拉曼激光雷达已经广泛应用于大气气溶胶、大气温度和水汽的空间分布及时间演变特征测量。为了获取北京污染期间大气气溶胶边界层的特征,2014年11月~2015年1月期间在中国科学院大学雁栖湖校区利用拉曼激光雷达进行连续观测。使用梯度法处理激光雷达观测数据得到边界层高度,同时与国家环保部提供的当地颗粒物浓度数据进行对比。观测期间灰霾天共出现15天,污染天出现27天,干净天出现24天。灰霾天、污染天和干净天三种情况下的平均大气边界层高度范围分别为0.6~0.9、0.9~1.3、1~1.9 km;PM2.5的质量浓度范围分别为143~203、77~90、17~34 g/m3;PM10的质量浓度范围分别为170~271、103~153、33~78 g/m3。研究结果表明:北京地区大气边界层高度对近地面颗粒物浓度具有明显的负相关影响。干净天、污染天和灰霾天下的PM2.5和PM10的质量浓度变化率随大气边界层高度降低而依次增大。灰霾天大气边界层高度引起的PM2.5质量浓度平均变化率为-242.4 gm-3/km,约为污染天（-114.8 gm-3/km）的两倍,干净天（-77.4 gm-3/km）的三倍;灰霾天大气边界层高度引起的PM10质量浓度平均变化率为-224.2 gm-3/km,约为污染天（-117.6 gm-3/km）的两倍,干净天（-90.4 gm-3/km）的两倍。     

基于太阳辐射计的气溶胶光学特性反演算法研究

介绍了一种利用太阳直接辐射和天空漫射辐射来反演气溶胶光学特性的方法,研究了其算法实现过程.结合太阳辐射计CE318所测得的太阳直射辐照度和天空漫射辐亮度数据,反演获得了晴朗天气下四个波段的气溶胶光学厚度、Angstrom参数、单次散射反照率、散射相函数和偏振相函数.算法的实现为解决光学遥感应用中气溶胶散射相函数和偏振相函数的测量问题提供了一个实用的方法.