SOFIA is an airborne observatory for far-infrared astronomy. Although SOFIA flies at altitudes of ∼41,000 feet, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The atmospheric parameter governing absorption is the total upward precipitable water vapor, PWV. In this paper we investigated if data of the Earth’s atmosphere provided by the European Centre for Medium-Range Weather Forecasts, ECMWF, can be used to determine spatially and time-resolved PWV data to allow a more precise calibration of far-infrared data taken with SOFIA along its flight path. We found that PWV values obtained from ECMWF correlate extremely well with independently determined PWV values obtained with the FIFI-LS instrument onboard SOFIA. We determined maximum observing time intervals (depending on the pressure altitude SOFIA is flying at) within which the upward PWV value changes inflight by less than a certain amount. We also present a new calibration method which enhances data quality and observing efficiency with FIFI-LS significantly. Furthermore our new method is universal and may be applied to data from all of SOFIA's instruments.

SOFIA 是一个用于远红外天文学的机载天文台。尽管 SOFIA 的飞行高度约为 41,000 英尺，但从地球大气层内进行的任何远红外观测仍会受到吸收天文信号的水蒸气的阻碍。控制吸收的大气参数是向上可降水的总水蒸气，PWV。在本文中，我们调查了欧洲中期天气预报中心 (ECMWF) 提供的地球大气数据是否可用于确定空间和时间分辨 PWV 数据，以便更精确地校准远红外数据。 SOFIA 沿其飞行路线。我们发现从 ECMWF 获得的 PWV 值与使用 SOFIA 上的 FIFI-LS 仪器获得的独立确定的 PWV 值非常相关。我们确定了最大观测时间间隔（取决于 SOFIA 飞行的压力高度），在该间隔内向上 PWV 值在飞行中的变化小于一定量。我们还提出了一种新的校准方法，可显着提高 FIFI-LS 的数据质量和观察效率。此外，我们的新方法是通用的，可以应用于来自 SOFIA 的所有仪器的数据。