# Extended guide to the Cloud Type RGB

## Print Version

## Chapter I: Introduction

- Introduction

### Introduction

This document is about the Cloud Type RGB, a new product for European users of GEO satellite data, which can be constructed using data from the Flexible Combined Imager (FCI) on the Meteosat Third Generation (MTG) satellite system. It uses one of the new FCI channels. This document is an extended guide discussing its characteristics in detail; a quick guide is also available on the EUMeTrain webpage.

In this guide several examples are shown, created mainly from proxy data from imagers on American geostationary satellites (GOES/ABI) and polar satellites (NPP and NOAA-20/VIIRS). At the time the document was created, FCI was not yet operational, so the characteristics of the FCI Cloud Type RGB were tested using preliminary commissioning data. Similar features were found as with the proxy data. Some examples created from the FCI preliminary commissioning data are presented in this guide.

The Cloud Type RGB provides improved detection of high-level thin features, such as thin cirrus clouds and aerosol plumes. The main application areas of the Cloud Type RGB are detection of very thin cirrus and higher-level aerosol clouds, and visual differentiation of cloud types, with some limitations. It can also provide some information about areas with dry airmasses.

Technical notes:

- The preliminary commissioning FCI data may be affected by processing artefacts. The data do not include straylight corrections, and only preliminary calibration and navigation have been applied.
- The channel names in the document consist of characters and numbers: VIS stands for visible, NIR for near-infrared, IR for infrared and WV for infrared water vapour absorbing band; the number indicates the central wavelength in µm.
- The radiosonde data are taken from the Wyoming University database.
- The “Total Column Water Vapour” parameter of the ECMWF model was used: this is the vertically integrated atmospheric water vapour amount from the surface to the top of the atmosphere. The unit is kg/m2 (equivalent to mm of precipitation, if it were all to be converted to precipitation).
- VIIRS data were processed using CSPP software. The VIIRS images were produced using the HAWK visualization system (developed by the Hungarian Meteorological Service).
- GOES/ABI images were either taken from the EUMeTrain ePort-PRO tool or processed and visualized using McIdas-V software.
- The preliminary commissioning FCI data were processed using software modules developed by the Hungarian Meteorological Service and visualized using the HAWK visualization system.