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Spatiotemporal Variations of Microwave Land Surface Emissivity(MLSE)over China Derived from Four-Year Recalibrated Fengyun 3B mwri Data

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Advances in Atmospheric Sciences 2022年第9期39卷 1536-1560页

作者： Rui LI Jiheng HU Shengli WU Peng ZHANG Husi LETU Yu WANG Xuewen WANG Yuyun FU Renjun ZHOU Ling SUN School of Earth and Space Sciences Comparative Planetary Excellence Innovation CenterChinese Academy of SciencesUniversity of Science and Technology of ChinaHefei 230026China State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei 230026China National Satellite Meteorological Center of China Meteorological Administration Beijing 100044China State Key Laboratory of Remote Sensing Science The Aerospace Information Research InstituteChinese Academy of Sciences(CAS)Beijing 100101China Green Earth Research Inc. SlingerlandsNew York 12259USA

Microwave Land Surface Emissivity(MLSE)over China under both clear and cloudy sky conditions was retrieved using measurements of recalibrated microwave brightness temperatures(Tbs)from Fengyun-3B Microwave Radiation Imager(FY-3B mwri),combined with cloud properties derived from Himawari-8 Advanced Himawari Imager(AHI)observations.The contributions from cloud particles and atmospheric gases to the upwelling Tbs at the top of atmosphere were calculated and removed in radiative transfer.The MLSEs at horizontal polarizations at 10.65,18.7,and 36.5 GHz during 7 July 2015 to 30 June 2019 over China showed high values in the southeast vegetated area and low values in the northwest barren,or sparsely vegetated,area.The maximum values were found in the belt area of the Qinling-Taihang Mountains and the eastern edge of the Qinghai-Tibet Plateau,which is highly consistent with MLSEs derived from AMSR-E.It demonstrates that the measurements of FY-3B mwri Tbs,including its calibration and validation,are reliable,and the retrieval algorithm developed in this study works well.Seasonal variations of MLSE in China are mainly driven by the combined effects of vegetation,rainfall,and snow cover.In tropical and southern forest regions,the seasonal variation of MLSE is small due to the enhancement from vegetation and the suppression from rainfall.In the boreal area,snow causes a significant decrease of MLSE at 36.5 GHz in winter.Meanwhile,the MLSE at lower frequencies experiences less suppression.In the desert region in Xinjiang,increases of MLSEs at all frequencies are observed with increasing snow cover.

关键词： satellite remote sensing microwave surface emissivity Fengyun-3B mwri Himawari-8 AHI

Evaluation of the Long-term Performance of Microwave Radiation Imager Onboard Chinese Fengyun Satellites

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Advances in Atmospheric Sciences 2023年第7期40卷 1257-1268页

作者： Wenying HE Hongbin CHEN Xiang’ao XIA Shengli WU Peng ZHANG Key Labratory for Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China

Accurate brightness temperature(BT)is a top priority for retrievals of atmospheric and surface parameters.Microwave Radiation Imagers(mwris)on Chinese Fengyun-3(FY-3)serial polar-orbiting satellites have been providing abundant BT data since 2008.Much work has been done to evaluate short-term mwri observations,but the long-term performance of mwris remains unclear.In this study,operational mwri BTs from 2012–19 were carefully examined by using simultaneous Advanced Microwave Scanning Radiometer 2(AMSR2)BTs as the reference.The BT difference between mwri/FY3B and AMSR2 during 2012–19 increased gradually over time.As compared with mwri/FY3B BTs over land,those of mwri/FY3D were much closer to those of AMSR2.The ascending and descending orbit difference for mwri/FY3D is also much smaller than that for mwri/FY3B.These results suggested the improvement of mwri/FY3D over mwri/FY3B.A substantial BT difference between AMSR2 and mwri was found over water,especially at the vertical polarization channels.A similar BT difference was found over polar water based on the simultaneous conical overpassing(SCO)method.Radiative transfer model simulations suggested that the substantial BT differences at the vertical polarization channels of mwri and AMSR2 over water were partly contributed by their difference in the incident angle;however,the underestimation of the operational mwri BT over water remained a very important issue.Preliminary assessment of the operational and recalibrated mwri BT demonstrated that mwri BTs were substantially improved after the recalibration,including the obvious underestimation of the operational mwri BT at the vertical polarization channels over water was corrected,and the time-dependent biases were reduced.

关键词： FY-3 satellites mwri AMSR2 brightness temperature recalibration

Retrieval of Snow Depth on Sea Ice in the Arctic Using the FengYun-3B Microwave Radiation Imager

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Journal of Ocean University of China 2019年第3期18卷 580-588页

作者： LI Lele CHEN Haihua GUAN Lei College of Information Science and Engineering Ocean University of China

Snow on sea ice is a sensitive indicator of climate change because it plays an important role regulating surface and near surface air temperatures. Given its high albedo and low thermal conductivity, snow cover is considered a key reason for amplified warming in polar regions. This study focuses on retrieving snow depth on sea ice from brightness temperatures recorded by the Microwave Radiation Imager(mwri) on board the FengYun(FY)-3 B satellite. After cross calibration with the Advanced Microwave Scanning Radiometer-EOS(AMSR-E) Level 2 A data from January 1 to May 31, 2011, mwri brightness temperatures were used to calculate sea ice concentrations based on the Arctic Radiation and Turbulence Interaction Study Sea Ice(ASI) algorithm. Snow depths were derived according to the proportional relationship between snow depth and surface scattering at 18.7 and 36.5 GHz. To eliminate the influence of uncertainties in snow grain sizes and sporadic weather effects, seven-day averaged snow depths were calculated. These results were compared with snow depths from two external data sets, the IceBridge ICDIS4 and AMSR-E Level 3 Sea Ice products. The bias and standard deviation of the differences between the mwri snow depth and IceBridge data were respectively 1.6 and 3.2 cm for a total of 52 comparisons. Differences between mwri snow depths and AMSR-E Level 3 products showed biases ranging between-1.01 and-0.58 cm, standard deviations from 3.63 to 4.23 cm, and correlation coefficients from 0.61 to 0.79 for the different months.

关键词： mwri AMSRE brightness temperature snow depth inter-sensor calibration sea ice concentration

MODELING AND QUANTITATIVE RETRIEVAL OF FINITE FIELD FOR THE TROPICAL SEA SURFACE WIND SPEED OF THE FY-3B MICROWAVE IMAGER

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Journal of Tropical Meteorology 2015年第1期21卷 84-91页

作者：安大伟陆风窦芳丽张鹏 National Satellite Meteorological Center China Meteorological Administration

The purpose of this study is to select a suitable sea wind retrieval method for FY-3B(mwri). Based on the traditional empirical model of retrieving sea surface wind speed, and in the case of small sample size of FY-3B satellite load regression analysis, this paper analyzes the channel differences between the FY-3B satellite microwave radiation imager(mwri) and TMI onboard the TRMM. The paper also analyzes the influence of these differences on the channel in terms of receiving temperature, including channel frequency, sensitivity and scaling precision. Then, the limited range of new model coefficient regression analysis is determined(in which the channel range settings include the information and features of channel differences), the regression methods of the finite field are proposed, and the empirical model of wind speed retrieval applicable to mwri is obtained, which achieves robust results. Compared to the TAO buoy data, the mean deviation of the new model is 0.4 m/s, and the standard deviation is 1.2 m/s. In addition,the schematic diagram of the tropical sea surface wind speed retrieval is provided.

关键词： microwave radiometry tropical sea surface wind mwri FY-3B

FY-3B/mwri与GCOM-W1/AMSR-2亮温数据在北极地区的交叉定标

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遥感学报 2020年第8期24卷 1032-1044页

作者：唐晓彤陈海花管磊李乐乐中国海洋大学信息科学与工程学院海洋技术系青岛266100 青岛海洋科学与技术国家实验室区域海洋动力学与数值模拟功能实验室青岛266071

为了使搭载在风云三号B星上的微波成像仪mwri(Microwave Radiation Imager)与搭载在GCOM-W1(Global Change Observation Mission 1st-Water)卫星上的AMSR-2(Advanced Microwave Scanning Radiometer 2)的数据可以衔接使用,并为以后FY-3B/mwri北极地区遥感参数反演研究提供基础,以GCOM-W1/AMSR-2数据为对比数据,北极海洋区域为研究区域,对两传感器对应的10个通道的升、降轨亮温数据进行交叉定标。首先,对mwri和AMSR-2各通道逐月在研究区域进行偏差分析;其次,对mwri和AMSR-2各通道逐月在海冰区域和开阔水域进行偏差分析;最后,对mwri和AMSR-2各通道逐月在研究区域进行交叉定标,并对定标结果进行评价。研究结果表明:(1)mwri各通道亮温数据小于AMSR-2,且相同频率下,垂直极化各通道逐月平均偏差的绝对值大于水平极化各通道,升、降轨数据在各通道的差异较小,逐月平均偏差的差值小于1 K;(2)在海冰区域,升、降轨各通道逐月平均偏差相差小于1 K,在开阔水域则介于0—1.5 K;(3)通过进行线性回归分析,mwri和AMSR-2各通道相关系数大于0.99,具有强相关性,并得到升、降轨各通道各月份交叉定标的斜率和截距;(4)定标后mwri的亮温值与AMSR-2的亮温值一致性较好,说明交叉定标的效果较好。

关键词：遥感 mwri AMSR-2 北极地区亮度温度交叉定标风云三号

利用风云三号微波成像仪资料遥感“桑达”台风降雨云结构

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地球物理学报 2012年第9期55卷 2843-2853页

作者：李小青杨虎游然赵凤生乔延利中国气象局中国遥感卫星辐射测量和定标重点开放实验室国家卫星气象中心北京100081 中国科学院安徽光学精密机械研究所合肥230031 GCESS北京师范大学北京100875

本文利用搭载于我国风云三号B星上的微波成像仪(mwri)观测亮温数据,结合戈达德廓线反演算法,对1102号"桑达"台风地面雨强和降雨云结构进行反演试验.利用AMSR-E业务降水产品对地面雨强反演结果进行了检验,结果表明,mwri和AMSR-E反演的地... 详细信息

本文利用搭载于我国风云三号B星上的微波成像仪(mwri)观测亮温数据,结合戈达德廓线反演算法,对1102号"桑达"台风地面雨强和降雨云结构进行反演试验.利用AMSR-E业务降水产品对地面雨强反演结果进行了检验,结果表明,mwri和AMSR-E反演的地面雨强在空间分布上非常吻合,相关性达76%,均方根误差约2.8mm/h,二者的观测亮温及地面雨强反演结果具有较好的一致性.提取洋面台风雨区的平均水凝物廓线,其垂直结构显示,雨水和可降冰含量丰富,随高度变化明显,且具有明显峰值高度,云水和云冰含量则较少,且随高度变化不明显;当降水增强时,雨水和可降冰各层含量稳定增加,且峰值高度基本保持不变,云水和云冰含量则增幅不稳,且峰值高度有所改变.地面雨强随距台风中心距离的变化阐释了台风的螺旋结构及降水特点,距台风中心距离0.3°和0.6°附近分别出现了地面雨强峰值和次峰值,且66%的降水集中在距台风中心距离1°的空间范围内.mwri提供的台风地面雨强和降雨云垂直信息具有较高的可信度,对于我们监测台风降水、分析台风降水结构的时空演变特征以及数值预报模式应用等具有重要的参考价值.

关键词：风云三号B星 mwri 台风降雨云结构

基于FY-3 mwri数据的北极海冰密集度反演研究

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冰川冻土 2020年第4期42卷 1135-1144页

作者：吴展开王星东王峰河南工业大学信息科学与工程学院河南郑州450001 中国科学院遥感与数字地球研究所北京100094

以ASI算法(ARTIST sea ice algorithm)为基础,得到基于风云3C气象卫星(FY-3C)微波辐射计(mwri)数据的纯水与纯冰系点值,利用插值方法确定基于FY-3mwri数据的ASI海冰密集度计算公式,采用大津法(Otsu算法)得到基于mwri数据的天气滤波器阈... 详细信息

以ASI算法(ARTIST sea ice algorithm)为基础,得到基于风云3C气象卫星(FY-3C)微波辐射计(mwri)数据的纯水与纯冰系点值,利用插值方法确定基于FY-3mwri数据的ASI海冰密集度计算公式,采用大津法(Otsu算法)得到基于mwri数据的天气滤波器阈值。以2016年1月数据为例,对北极海冰密集度进行反演,并与美国国家冰雪数据中心(NSIDC)以及德国不莱梅大学提供的海冰密集度产品进行对比验证。结果表明:基于mwri数据得到的1月平均海冰面积以及平均密集度均介于二者之间,其中平均密集度与不莱梅产品更接近,仅相差1.310%。与风云卫星空间分辨率为250m的中分辨率光谱成像仪(MERSI)数据得到的结果进行对比,发现二者的海冰外缘线基本一致,MERSI数据得到的海冰密集度以及海冰面积比mwri数据得到的结果分别高出5.029%、9.318%。因此,应用该方法可有效推进mwri数据反演北极海冰密集度,进而监测北极海冰分布和变化。

关键词： FY-3 mwri 海冰密集度 ASI算法北极

mwri与AMSR-E亮温数据在极地冰盖区的对比分析

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遥感技术与应用 2014年第5期29卷 752-760页

作者：陈洁武胜利国家卫星气象中心北京100081

作为我国第一个星载微波遥感仪器,搭载在FY-3B上的微波成像仪(mwri)的数据质量和应用前景引起了广大科研工作者的普遍关注。为充分了解该传感器的数据质量,采用星星交叉对比的方法,以极地为研究区域,AMSR-E亮温数据作为对比值,开展针对M... 详细信息

作为我国第一个星载微波遥感仪器,搭载在FY-3B上的微波成像仪(mwri)的数据质量和应用前景引起了广大科研工作者的普遍关注。为充分了解该传感器的数据质量,采用星星交叉对比的方法,以极地为研究区域,AMSR-E亮温数据作为对比值,开展针对mwri的亮温数据处理和评价等工作。研究结果表明:mwri与AMSR-E对极地区域的观测数据基本一致,整体趋势略偏小1.64K;亮温差异随目标亮温的变化而变化,偏差值与亮温值呈正相关;不同通道比较,10v和36v对比结果最差,偏差绝对值和均方根误差均超过3K;10、18和23h通道对比结果最好,平均偏差绝对值小于0.8K,均方根误差小于1.4K,小于3K的误差比例在98%以上;从线性回归分析所得斜率、截距、可决系数和均方根误差值显示,两者点对点数据值存在一定的偏差,但在数值整体趋势上具有明显的一致性,H极化比V极化对比结果更好;不同间隔的观测时次结果表明,间隔时间越长,V极化的对比差异越大。

关键词：被动微波亮度温度交叉对比 mwri AMSR-E

基于反射率和亮度温度的锡林郭勒积雪深度估算

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干旱区地理 2020年第6期43卷 1567-1572页

作者：李慧融锡林浩特国家气候观象台内蒙古锡林浩特026000

积雪是我国西北干旱半干旱区重要的水资源,也是影响全球气候变化的重要因子之一。目前光学影像反射率和雷达亮温数据是积雪遥感领域的主要数据,本文首次结合两类遥感数据估算积雪深度,并比较偏最小二乘法和机器学习算法(人工神经网络、... 详细信息

积雪是我国西北干旱半干旱区重要的水资源,也是影响全球气候变化的重要因子之一。目前光学影像反射率和雷达亮温数据是积雪遥感领域的主要数据,本文首次结合两类遥感数据估算积雪深度,并比较偏最小二乘法和机器学习算法(人工神经网络、支持向量机和随机森林算法)在积雪深度估算方面的表现。以锡林郭勒盟2012—2015年积雪深度数据为例,基于反射率和亮度温度相结合的积雪深度估算精度优于单个数据源,且随机森林算法表现最好,均方根误差为2.93 cm,满足实际应用的需求。研究结果对我国西北地区水资源分布、生态环境评估等研究具有重要意义。

关键词：积雪深度 MODIS mwri 机器学习