Infrared Fourier Spectrometer 2 (IKFS‐2) radiance assimilation at ECMWF

Abstract

Meteorological satellites launched as part of the Russian space programme have not been widely used in global numerical weather prediction (NWP) to date. There is particular interest in the Meteor‐M series of sun‐synchronous spacecraft, as it is anticipated that future launches will operate in currently unobserved orbital planes complementary to those occupied by Europe, the United States, and China. One of the sensors carried on board these satellites is the Infrared Fourier Spectrometer 2 (IKFS‐2), which observes a spectrum of atmospheric radiation over the wavenumber range 660–2,000.5 cm−1. The IKFS‐2 is thus similar to earlier hyperspectral sensors such as the Infrared Atmospheric Sounding Interferometer (IASI) and the Cross‐track Infrared Sounder (CrIS), both of which have been used operationally at the European Centre for Medium‐range Weather Forecasts (ECMWF) for many years. This study investigates the quality of IKFS‐2 radiance measurements from the Meteor‐M‐N2 satellite and performs assimilation experiments to assess the impact of these data on the ECMWF analysis and forecasting system. Measured by statistical indicators of the observation fit to short‐range forecasts, the IKFS‐2 performs as well as IASI and CrIS amongst channels sensitive to stratospheric and tropospheric temperature. The assimilation experiments indicate up to 0.5% improvement in headline forecast scores, although the medium‐range impact is mixed and for most parts nonsignificant. One factor that currently limits the impact of IKFS‐2 is poor data timeliness and availability: observations are available for assimilation typically only 75% of the time during the test periods. It is expected, though, that such logistical problems can be overcome, and efforts are already underway to improve data dissemination.