Abstract Land surface temperature (LST) is increasingly needed for studying the functioning of the Earth's surface at local to global scale. Radiative transfer (RT) models that simulate top of atmosphere (TOA) radiance are essential tools to derive accurate LST from thermal infrared (TIR) signals of Earth observation (EO) satellites. DART (Discrete Anisotropic Radiative Transfer) is one of the most accurate and comprehensive three-dimensional models that simulate RT in the Earth-atmosphere system. Up to version 5.7.3, the mean absolute error (MAE) of DART atmospheric TIR radiance of six standard atmospheres (USSTD76, TROPICAL, MIDDLATSUM, MIDDLATWIN, SUBARCSUM, SUBARCWIN) over 3.5 μm - 20 μm was 3.1 K compared to the reference atmospheric RT model MODTRAN, which is much larger than the 1 K accuracy needed by most LST applications. Also, the radiance error reached 2.6 K for some TIR bands whereas the noise equivalent differential temperature (NeDT) of satellite TIR sensor is usually less than 0.4 K. Recently, the DART atmospheric RT modelling was greatly improved by (1) introducing the equivalent absorption cross-section of five most absorbing gases (H2O, CO2, O3, CH4, N2O), and (2) implementing a double-layer thermal emission method. The MAE of DART atmospheric TIR radiance of six standard atmospheres and actual atmospheres over France and the Mediterranean Sea is now better than 1.0 K. The band radiance error is less than 0.2 K in the EO satellite TIR bands. DART is still accurate if the temperature profiles of standard atmospheres are offset by less than 6 K and if the viewing zenith angle is less than 50°. In short, the improved DART meets the requirements of both LST applications, and present and future TIR EO satellite missions. It is already available to scientists ( https://dart.omp.eu ).

中文翻译：

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DART：用于模拟大气辐射顶部的热红外辐射传输模型的改进

摘要 地表温度 (LST) 越来越需要用于研究地球表面在局部到全球范围内的功能。模拟大气顶部 (TOA) 辐射的辐射传输 (RT) 模型是从地球观测 (EO) 卫星的热红外 (TIR) 信号中获取准确 LST 的重要工具。DART（离散各向异性辐射传递）是模拟地球大气系统中RT的最准确、最全面的三维模型之一。在版本 5.7.3 之前，六个标准大气（USSTD76、TROPICAL、MIDDLATSUM、MIDDLATWIN、SUBARCSUM、SUBARCWIN）在 3.5 μm - 20 μm 上的 DART 大气 TIR 辐射的平均绝对误差 (MAE) 与参考大气相比为 3.1 K RT 模型 MODTRAN，远大于大多数 LST 应用所需的 1 K 精度。还，一些 TIR 波段的辐射误差达到 2.6 K，而卫星 TIR 传感器的噪声等效温差（NeDT）通常小于 0.4 K。最近，DART 大气 RT 建模通过（1）引入等效吸收交叉五种最吸收气体（H2O、CO2、O3、CH4、N2O）的部分，以及 (2) 实施双层热排放方法。DART大气TIR辐射的6个标准大气和法国和地中海实际大气的MAE现在优于1.0 K。EO卫星TIR波段的波段辐射误差小于0.2 K。如果标准大气的温度分布偏移小于 6 K 并且视角小于 50°，DART 仍然是准确的。简而言之，改进后的 DART 满足 LST 应用以及当前和未来 TIR EO 卫星任务的要求。它已经可供科学家使用 (https://dart.omp.eu)。