We propose a physically-based methodology for sea-surface skin-temperature (SST) retrievals from daytime spectra recorded by the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI). The approach, which takes sun light into account, minimizes the differences between measured and computed radiances at numerous points within two windows centered near 3.7 and 4.0 μm. We demonstrate that, even when the solar contribution is large, with brightness temperatures increased by several tens of kelvin at the shortest wavelengths, very consistent SSTs are retrieved in both windows. Furthermore, the values obtained are, after correction for the cool-skin effect, in excellent agreement (<0.05 K on average) with the in-situ measurements of the depth temperature provided by nearby drifters. This opens renewed perspectives for daytime SST determinations from space, since the IASI mid-infrared windows used here provide SSTs that are, with respect to those retrieved around 9 and 11 μm, much less sensitive to errors in the computed radiative contribution of water vapor.

我们提出了一种基于物理的方法，用于从高光谱红外大气探测干涉仪 (IASI) 记录的白天光谱中检索海面皮肤温度 (SST)。该方法将太阳光考虑在内，最大限度地减少了中心在 3.7 和 4.0 微米附近的两个窗口内多个点的测量和计算辐射之间的差异。我们证明，即使太阳贡献很大，在最短波长处亮度温度增加了几十开尔文，在两个窗口中都可以检索到非常一致的 SST。此外，在校正冷皮效应后，获得的值与附近漂流者提供的深度温度的原位测量值非常一致（平均<0.05 K）。