Study of ice cloud properties from infrared satellite measurements

<p class="AbstractText"><span lang="EN-US">This study aims to explore and quantify the added value of the far-infrared for the restitution of ice cloud optical properties with the future instrument from the Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM, Palchetti et al. (2020)) mission from the European Space Agency (ESA). FORUM</span> <span lang="EN-US">will provide new insight into the far infra-red Earth&#8217;s radiation budget and its climate feedbacks, such as those related to the water vapor and ice clouds. FORUM will measure the infrared (IR) emission spectrum of the Earth at the top of the atmosphere between 100-1600 cm^-1, with a spectral resolution around 0.5 cm^-1. This work aims at preparing and exploiting future FORUM observations in synergy with observations from the Infrared Atmospheric Sounding Interferometer - New Generation (IASI-NG, Crevoisier et al., 2014).</span></p> <p class="AbstractText"><span lang="EN-US">This study applies the algorithm recently developed by Leonarski et al. (2021) to retrieve ice cloud properties from IASI and IASI-NG instruments using the Radiative Transfer for TOVS (RTTOV) model (Saunders et al., 2018). This algorithm was here adapted for use of the FORUM instrument, as well as the instrumental synergy between FORUM and IASI-NG. The algorithm was tested on synthetic FORUM measurements derived from atmospheric vertical profiles coming from a global operational short-range forecasts database from the Center for Medium-range Weather Forecasts (ECMWF). The first results of this study show that the far- and mid- infrared measurements can be successfully used to inverse ice cloud properties (such as the water path (IWP), and the cloud top and bottom heights). Results from the comparison between FORUM and IASI-NG performances will be shown, as well as the added value of using the instrumental synergy between FORUM and IASI-NG for the study of ice cloud properties. Finally, the sensitivity of the retrieved properties to the microphysical model used in the forward model will also discussed.</span></p> <p class="AbstractText"><span lang="EN-US">&#160;</span></p> <p>References</p> <p class="RefText">Crevoisier, C., Clerbaux, C., Guidard, V., Phulpin, T., Armante, R., Barret, B., ... <span lang="EN-US">& Stubenrauch, C. (2014). Towards IASI-New Generation (IASI-NG): impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables. <em>Atmospheric Measurement Techniques</em>, <em>7</em>(12), 4367-4385.</span></p> <p class="RefText"><span lang="EN-US">Leonarski, L., C-Labonnote, L., Compi&#232;gne, M., Vidot, J., Baran, A. J., & Dubuisson, P. (2021). Potential of Hyperspectral Thermal Infrared Spaceborne Measurements to Retrieve Ice Cloud Physical Properties: Case Study of IASI and IASI-NG. <em>Remote Sensing</em>, <em>13</em>(1), 116.</span></p> <p class="RefText"><span lang="EL">Palchetti, L., Brindley, H., Bantges, R., Buehler, S. A., Camy-Peyret, C., Carli, B., ... & Serio, C. (2020). unique far-infrared satellite observations to better understand how Earth radiates energy to space.&#160;<em>Bulletin of the American Meteorological Society</em>,&#160;<em>101</em>(12), E2030-E2046.</span></p> <p class="RefText"><span lang="EN-US">Saunders, R., Hocking, J., Turner, E., Rayer, P., Rundle, D., Brunel, P., ... & Lupu, C. (2018). An update on the RTTOV fast radiative transfer model (currently at version 12). Geoscientific Model Development, 11(7), 2717-2737.</span></p>