Radiative Effects of Various Cloud Types as Classified by the Split Window Technique over the Eastern Sub-tropical Pacific Derived from Collocated ERBE and AVHRR Data
Radiative Effects of Various Cloud Types as Classified by the Split Window Technique over the Eastern Sub-tropical Pacific Derived from Collocated ERBE and AVHRR Data
复制标题
根据并置 ERBE 和 AVHRR 数据推导出的东副热带太平洋上各种云类型的分裂窗口技术的辐射效应
DOI：
10.2151/jmsj.80.1383
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发表时间：
2002
影响因子：
3.1
通讯作者：
S. Ackerman
中科院分区：
文献类型：
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作者：
T. Inoue;S. Ackerman
利用同步和同位的地球辐射收支实验（埃尔贝）S-8资料和NOAA-9的高级甚高分辨率辐射计（AVHRR）资料，研究了几种用分裂窗（11和12 μm）技术分类的云类型的辐射效应。研究的参数是云辐射强迫（CRF），在大气顶部的晴天和多云的短波通量（SW）和长波通量（OLR）之间的差异。在计算CRF时，明确SW和OLR的准确性至关重要。使用重合和同位AVHRR图像数据评价埃尔贝数据集中的清晰场景ID。由埃尔贝定义的清晰足迹的平均可见光反射率和SW相当小，分别为3.2%和89.0 Wm-2。然而，使用我们的技术计算的值较小，分别为2.7%和83.9 Wm-2。使用配置的AVHRR图像数据提高了清晰的足迹定义，并意味着在计算CRF时，应注意单独从埃尔贝数据。对分裂窗分类的几种云型的CRF进行了比较。积雨云对西南和OLR大气顶部辐射的影响最大。卷云和低层积云对OLR的影响相似，但对SW的影响差异较大，低层积云对SW的影响远大于卷云。一些光学薄卷云显示出正的云辐射强迫（变暖效应）。研究了OLR与分裂窗技术分类的云类型（包括无云）之间的关系。通过使用分裂窗口通道之间的亮度温度差，OLR估计无云和低层积云相比，由美国国家海洋和大气管理局（NOAA）业务算法估计的OLR时，得到改善。
The radiative effects of several cloud types as classified by the split window (11 and 12 μm) technique were studied using coincident and collocated Earth Radiation Budget Experiment (ERBE) S-8 data and Advanced Very High Resolution Radiometer (AVHRR) data from NOAA-9. The parameter investigated was cloud radiative forcing (CRF), the difference between clear and cloudy shortwave flux (SW) and longwave flux (OLR) at the top of the atmosphere. In computing the CRF, the accuracy of clear SW and OLR is essential. Clear scene IDs in the ERBE dataset were evaluated using coincident and collocated AVHRR image data. The mean visible reflectance and SW for clear footprints defined by the ERBE are reasonably small and are 3.2% and 89.0 Wm-2, respectively. However, the values computed using our technique are smaller, 2.7% and 83.9 Wm-2, respectively. The use of collocated AVHRR image data improves clear footprint definition and implies that care should be taken when computing CRF from ERBE data alone. The CRF from several cloud types classified by the split window were compared. Cumulonimbus clouds show the largest impact on top of the atmosphere radiation for both SW and OLR. Cirrus and lowlevel cumulus clouds have similar effects on OLR, but large differences between them are seen for SW. The impact of low-level cumulus clouds on SW is much larger than that of cirrus clouds. Some optically thin cirrus clouds show positive cloud radiative forcing (warming effect). The relationships between OLR and cloud types (including cloud-free) as classified by the split window technique were investigated. By using brightness temperature differences between the split window channels, OLR estimation is improved for cloud-free and low-level cumulus clouds when compared with OLR estimated by the National Oceanic and Atmospheric Administration (NOAA) operational algorithm.
Inoue,T.：“从 NOAA 极轨卫星上的分割窗口推断出云类型的昼夜云量变化。”
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