Comment on amt-2021-290

Abstract

Satellite measurements enable quantification of atmospheric temperature, humidity, and trace gas vertical profiles. The majority of current instruments operate on polar orbiting satellites and either in the thermal/mid-wave or in the shortwave infrared spectral regions. We present a new multispectral instrument concept for improved measurements from geostationary orbit (GEO) with sensitivity to the boundary layer. The JPL GEO-IR sounder, which is an imaging Fourier Transform Spectrometer, uses a wide spectral range (1–15.4 μm), encompassing both reflected solar and thermal emission bands to improve sensitivity to the lower troposphere and boundary layer. We perform retrieval simulations for both clean and polluted scenarios that also encompass different temperature and humidity profiles. The results illustrate the benefits of combining shortwave and thermal infrared measurements. In particular, the former adds information in the boundary layer, while the latter helps to separate near-surface and mid-tropospheric variability. The performance of the JPL GEO-IR sounder is similar to or better than currently operational instruments. The proposed concept is expected to improve weather forecasting, severe storm tracking and forecasting, and also benefit local and global air quality and climate research.