The forthcoming Earth Explorer 9 - FORUM (Far Infrared Outgoing Radiation Understanding and Monitoring) mission will provide global sounding of the Earth's thermal emission to space in the Far-Infrared (FIR, from 100 to 600 cm-1). The on-board Fourier Transform Spectrometer (FTS) will deliver a wide set of TOA radiances during the mission lifetime that will represent a benchmark for future climate missions. Atmospheric water vapour plays a key role in modulating the OLR in the FIR hence the acquired spectra will also enable future improvements of FIR water vapour spectroscopy. The current uncertainty on spectroscopic data and continuum models is one of the main sources of error on the estimation of the atmospheric radiative properties in the FIR, especially in clear sky conditions where the strong absorption provided by the water vapour rotational band is almost totally responsible for the atmospheric extinction. In preparation for the FORUM-EE9 mission launch in 2026, the analysis of the consistency between observations from prototypes of the FORUM FTS with similar spectral resolution and noise performance and RTM simulations can be a first step toward an improvement of the water vapour spectroscopic data. Here we exploit the balloon-borne measurements above Teresina (Brazil) from the Radiation Explorer in the Far InfraRed - Prototype for Applications and Development (REFIR-PAD) and aircraft observations above the North Sea from the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS). These measurements are used to assess the performances of different spectroscopic databases (HITRAN, AER, GEISA), coupled to different water vapor continuum parametrizations. The performances are assessed through a consistency analysis between measurements and simulations aimed to inform which best simulates the observed FIR spectra. The work will also demonstrate the capability of FORUM-like instruments to give a reliable contribution to spectroscopic improvements in the FIR.
Analysis of the Consistency Between FIR Spectroscopic Data and Airborne Measurements: Support to FORUM-EE9 Mission
2021
Abstract
The forthcoming Earth Explorer 9 - FORUM (Far Infrared Outgoing Radiation Understanding and Monitoring) mission will provide global sounding of the Earth's thermal emission to space in the Far-Infrared (FIR, from 100 to 600 cm-1). The on-board Fourier Transform Spectrometer (FTS) will deliver a wide set of TOA radiances during the mission lifetime that will represent a benchmark for future climate missions. Atmospheric water vapour plays a key role in modulating the OLR in the FIR hence the acquired spectra will also enable future improvements of FIR water vapour spectroscopy. The current uncertainty on spectroscopic data and continuum models is one of the main sources of error on the estimation of the atmospheric radiative properties in the FIR, especially in clear sky conditions where the strong absorption provided by the water vapour rotational band is almost totally responsible for the atmospheric extinction. In preparation for the FORUM-EE9 mission launch in 2026, the analysis of the consistency between observations from prototypes of the FORUM FTS with similar spectral resolution and noise performance and RTM simulations can be a first step toward an improvement of the water vapour spectroscopic data. Here we exploit the balloon-borne measurements above Teresina (Brazil) from the Radiation Explorer in the Far InfraRed - Prototype for Applications and Development (REFIR-PAD) and aircraft observations above the North Sea from the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS). These measurements are used to assess the performances of different spectroscopic databases (HITRAN, AER, GEISA), coupled to different water vapor continuum parametrizations. The performances are assessed through a consistency analysis between measurements and simulations aimed to inform which best simulates the observed FIR spectra. The work will also demonstrate the capability of FORUM-like instruments to give a reliable contribution to spectroscopic improvements in the FIR.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
