Development of a Nonlinear Statistical Method for Estimating the Downward Longwave Radiation at the Surface from Satellite Observations
Development of a Nonlinear Statistical Method for Estimating the Downward Longwave Radiation at the Surface from Satellite Observations
复制标题
DOI：
10.1175/1520-0426(2002)019
复制
发表时间：
2002-10
影响因子：
2.2
通讯作者：
Hai-Tien Lee;R. Ellingson
中科院分区：
文献类型：
--
作者：
Hai-Tien Lee;R. Ellingson
摘要本文提出了一种非线性统计方法，它直接利用卫星辐射观测来估计地表向下长波辐射（DLR），这是地表能量收支的一个必要组成部分。所提出的技术具有均方根回归误差约9 W m-2的晴空条件下，约4至8 W m-2的阴天条件下，取决于云的水平。它表明，这种技术可以产生无偏估计在大范围的气象条件下，这是气候研究的关键。敏感性研究表明，DLR对平均云量误差最敏感。总的来说，当云量的不确定性为±10%，云底压力的不确定性为±100 hPa时，瞬时DLR估计的综合误差（不包括地面气压误差的影响）约为7 ~ 12 W m-2。当云量的不确定性上升到30%时，组合DLR误差范围为约10至25 W m-2。这清楚…
Abstract This paper develops a nonlinear statistical method that uses satellite radiance observations directly to estimate the downward longwave radiation (DLR) at the earth's surface, a necessary component of the surface energy budget. The proposed technique has rms regression errors of about 9 W m–2 for clear-sky conditions, and about 4 to 8 W m–2 for overcast conditions, depending on the cloud levels. It is shown that this technique can produce unbiased estimates over a large range of meteorological conditions, which is crucial for climate studies. Sensitivity studies show that the DLR is most sensitive to errors in the cloud amount on average. Overall, the combined errors for an instantaneous DLR estimate, excluding the effects of the surface pressure errors, range from about 7 to 12 W m–2 when there is a ±10% uncertainty in cloud amount and a ±100 hPa uncertainty in cloud-base pressure. When the cloud amount uncertainty rises to 30%, the combined DLR error ranges from about 10 to 25 W m–2. This clear...