Title: Exploiting new observations of the sub-millimetre region to improve the forecast at ECMWF
Speaker: Sanjeevani Panditharatne (ECMWF)
Abstract: Ice clouds remain one of the largest sources of uncertainty in weather forecasting and climate modelling due to their complex formation and evolution mechanisms. Within the ECMWF’s Integrated Forecasting System, we currently assimilate a limited number of satellite observations sensitive to thinner ice clouds in all-sky conditions. However, as of July 2025, the first passive observations of the sub-millimetre region (frequency >300 GHz and wavelengths< 1mm) have been included in the all-sky system. These frequencies are significantly more sensitive to scattering from ice clouds and snow than the traditional microwave frequencies and are expected to provide new information about clouds. Here, we explore the impact of this new sensitivity on the forecast and inspect the mechanisms that are causing these changes.