Uncertainty of cloud parameters on satellite estimation of radiation budget in climate change study

气候变化研究中辐射收支卫星估算的云参数不确定性

• 批准号: 14380241
• 负责人: TAKAMURA Tamio
• 金额: $ 9.41万
• 依托单位: Chiba University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14380241/
• 关键词: radiation budget; climate change; optical characteristics of cloud; cloud radar; LIDAR; radiative forcing

We have the research results as follows,[Review and re-examination of optical characteristics of clouds for estimating the radiation budget and cloud radiative forcing with high accuracy]Up to now, we have continued to estimate the hourly data of cloudiness, cloud optical thickness, surface brightness temperature and downward solar radiation at the surface using the GMS-5 from 1996. These products should be validated with the data observed at the surface. Our team has been operating the SKYNET observation network in the East Asia for the research of cloud, aerosol and radiation issues in the climate change. The comparison gave two distinguished trends ; for clear days, the comparison shows the quite good agreement, but for cloudy days it has large discrepancies with more than 50W/m2 in some cases. This would bring serious effects on the estimation of radiation budget. So we have made the reason clear and improved the algorithm for estimation.The most important parameters for giving the … More se errors are ;(1)sensitivity change of sensor response, (2)digitization noise, and (3)inhomogeneity of cloud.Regarding the item (1), we have already analyzed this trend of degradation of GMS-5 and got the decrease of sensitivity with several percents per year. In this research, we have quantitatively estimated the effect compared with MODIS data. Since the GMS visible channel has a low resolution (6bit, 64 steps), and a second-order polynomial response for the input radiance, it is highly sensitive for the lower reflected radiance, in other words, a relatively thin cloud, and the poor sensitive for the high reflected radiance, such as thick clouds. The comparison with MODIS data gave the quantitative difference between them. Also the MODIS and the GMS take the same images of cloud simultaneously, but the satellite zenith angles are different which means the possibility of the radiance received from the cloud can give the error if the cloud is not plane parallel. The effect of 3-dimensional structure of cloud has been estimated. These analytical results in the project reflect our algorithms to estimate the cloud parameters and radiation budget. Less

我们的研究成果如下：[回顾和重新检查云的光学特性，以高精度地估计辐射收支和云辐射强迫]到目前为止，我们继续使用GMS-5从1996年开始估计云量，云光学厚度，地面亮温和地面向下太阳辐射的逐时数据。这些产品应使用在地面观察到的数据进行验证。我们的团队一直在东亚运营SKYNET观测网络，研究气候变化中的云、气溶胶和辐射问题。比较给出了两个明显的趋势;对于晴天，比较显示出相当好的一致性，但对于阴天，在某些情况下，其差异大于50 W/m2。这将给辐射收支的估算带来严重影响。为此，我们明确了原因，并改进了估计算法， ...更多信息 错误是;（1）传感器响应的灵敏度变化，（2）数字化噪声，（3）云的不均匀性，对于第（1）项，我们已经分析了GMS-5的这种退化趋势，并得到了每年几次的灵敏度下降。在这项研究中，我们定量估计的效果与MODIS数据相比。由于GMS可见光通道具有低分辨率（6 bit，64步）和对输入辐射的二阶多项式响应，因此它对较低的反射辐射（换句话说，相对薄的云）高度敏感，而对高反射辐射（例如厚云）不敏感。通过与MODIS数据的比较，给出了两者在数量上的差异。另外，MODIS和GMS同时拍摄相同的云图像，但卫星天顶角不同，这意味着如果云不是平面平行的，则从云接收到的辐射的可能性会产生误差。对云的三维结构的影响作了估计。这些分析结果反映了我们估算云参数和辐射收支的算法。少

项目成果

Overview of SKYNET and its Activities

• 作者: M. Yabuki;M. Shiobara;H. Kobayashi;M.Hayashi;K. Hara;K. Osada;H. Kuze;N. Takeuchi

Development of a Low Power and High Sensitivity Cloud Pro filing FM-CW Radar at 95 GHz

开发低功耗、高灵敏度 Cloud Pro 文件 95 GHz FM-CW 雷达

• 发表时间: 2004
• 期刊: ICCP (International Commission on Precipitation) 2005 Bologna, Italy
• 作者: Toshiaki TAKANO;Hiroshi KUMAGAI;Tamio TAKAMURA;Teruyuki NAKAJIMA
• 通讯作者: Teruyuki NAKAJIMA

M.Yabuki, H.Kuze, H.Kinjo, N.Takeuchi: "Determination of vertical distributions of aerosol optical parameters by use of multi-wavelength lidar data"Jpn. J. Appl. Phys. 42(2A). 686-694 (2003)

M.Yabuki、H.Kuze、H.Kinjo、N.Takeuchi：“利用多波长激光雷达数据确定气溶胶光学参数的垂直分布”Jpn。

T.Murayama, H.Kuze et al.: "An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia"Journal of Geophysical Research. 108(D23). ACE 19-1-ACE 19-7 (2003)

T.Murayama、H.Kuze 等人：“激光雷达产生的气溶胶光学特性与 ACE-Asia 期间东京附近机载测量的相互比较”地球物理研究杂志。

M.Yabuki, H.Kuze et al.: "Optical properties of aerosols in the marine boundary layer during a cruise from Tokyo, Japan to Fremantle, Australia"J. Meteorol. Soc. Jpn. 81(1). 151-162 (2003)

M.Yabuki, H.Kuze 等人：“从日本东京到澳大利亚弗里曼特尔的航行期间海洋边界层气溶胶的光学特性”J.