The spectroscopy of the υ = 1 → υ = 0 fundamental vibration-rotation band of nitric oxide (NO) in Earth's atmosphere is examined in depth in order to further assess the long-running dataset of infrared radiative cooling rates in the thermosphere from the SABER instrument on the NASA TIMED satellite. The fundamental band at 5.3 µm is shown to be almost solely responsible for the cooling by NO. The distribution of line strength in this band and the concentration of NO in the atmosphere are such that NO is remarkably transparent in Earth's atmosphere. Every fundamental band photon emitted in the nadir direction by NO in the thermosphere has a nearly 100% chance of hitting the Earth's surface before being absorbed by another NO molecule. The mean free paths of these photons exceed 5000 km. Vertical optical depths of the strongest NO absorption lines in 2 km thick layers in the thermosphere are less than 10⁻⁴ even during geomagnetically disturbed conditions. Consequently, nearly all of the radiation emitted by thermospheric NO escapes to space or to the lower atmosphere. Radiative excitation of thermospheric NO by upwelling infrared radiation (“earthshine”) from the troposphere is accurately assessed using measurements of infrared spectra made by the IASI instruments on the METOP satellites. Earthshine and solar excitation of NO are shown to compete with collisional excitation of NO by atomic oxygen below 110 km in polar regions and below 115 km in tropical regions. Therefore, NO 5.3 µm energy loss rates currently derived below ~ 115 km from measurements made by the SABER instrument on the NASA TIMED satellite are not representative of radiative cooling. Consequently, the current values of SABER-derived daily global power radiated from the thermosphere by NO are 5% to 15% too large. Approaches to further improve the SABER radiative cooling dataset are presented.

深入研究了地球大气中一氧化氮（NO）的υ= 1→υ= 0的基本振动-旋转带的光谱，以便进一步通过SABER评估热层中长期运行的红外辐射冷却速率数据集NASA TIMED卫星上的仪器。结果表明，5.3 µm的基带几乎完全是NO冷却的原因。该频带中线强度的分布以及大气中NO的浓度应使NO在地球大气中非常透明。在热层中，NO在天底方向发射的每个基带光子在被另一个NO分子吸收之前，几乎有100％的机会撞击地球表面。这些光子的平均自由程超过5000 km。⁻⁴即使在地磁干扰的情况下。因此，由热层NO发出的几乎所有辐射都逃逸到太空或低层大气中。通过使用IASI仪器对METOP卫星进行的红外光谱测量，可以准确地评估对流层上升红外辐射（“地光”）引起的热层NO的辐射激发。事实证明，在极地地区110 km以下和在热带地区115 km以下，NO的地光和太阳激发与原子氧的NO碰撞激发相竞争。因此，根据SABER仪器在NASA TIMED卫星上的测量结果得出，目前大约〜115 km以下的5.3 µm能量损失率不代表辐射冷却。所以，从热层通过NO辐射出的SABER衍生的每日全球总功率的当前值太大了5％至15％。提出了进一步改善SABER辐射冷却数据集的方法。