The MSG Global Instability Indices Product and Its Use as a Nowcasting Tool

Abstract

The European geostationary Meteosat Second Generation (MSG) satellite offers a variety of channels to use for various purposes, including nowcasting of convection. A number of applications have also been developed to make use of these new capabilities for nowcasting, especially for the detection and prediction of severe weather. The MSG infrared channel selection makes it possible to assess the air stability in preconvective, that is, still cloud-free, conditions. Instability indices are traditionally derived from radiosonde profiles. Such indices typically combine measures of the thermal and moisture properties and often only use a small quantity of vertical profile parameters. MSG-based temperature and moisture retrievals are used for the derivation of stability indices, which are a part of the MSG meteorological products derived centrally at the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Such indices are of an empirical nature, are often only applicable to certain geographic regions, and their thresholds are dependent on seasonal variation, but they can assess the likelihood of convection within the next few hours, thus providing a warning lead of about 6-9 h. Numerous test cases and the more quantitative verification process that was initiated by the South African Weather Service show the generally good warning potential of the derived instability fields. The added capability of a nearly continuous monitoring of the instability fields that is guaranteed by MSG's 15-min repeat cycle is most valuable, since it provides nowcasters with new information much more regularly than the twice-a-day soundings at only a limited number of radiosonde stations. The current EUMETSAT instability product is aimed at helping forecasters to focus their attention on a certain region, which can then be monitored more closely with other means, like satellite imagery and radar data, over the next few hours.

An Introduction to Himawari-8/9— Japan’s New-Generation Geostationary Meteorological Satellites

“…7.2 Atmospheric stability index product JMA plans to produce a stability index product for cloud-free conditions. This will be similar to the Legacy Atmospheric Profile (LAP) product for GOES-R developed by NOAA/NESDIS (Lee et al 2014) and the Global Instability Index (GII) for MSG developed by EUMETSAT (Koenig and Coning 2009). The product will provide atmospheric stability indices such as Convective Available Potential Energy (CAPE), K-Index, and precipitable water values.…”

Use of the GOES-R Split-Window Difference to Diagnose Deepening Low-Level Water Vapor

“…We hypothesize that the sudden increase at 1200 UTC corresponds with a new first-guess moisture field from the ECMWF. Koenig and de Coning (2009) acknowledge that ''the retrieved profiles tend to retain features of the first guess,'' so our hypothesis is a reasonable possibility. If true, this suggests that the retrieval in this case is more sensitive to the model first guess than to the SWD observations.…”

“…7. Column 3 is the MSG total precipitable water retrieval (Koenig and de Coning 2009); it uses the European Centre for Medium-Range Weather Forecasts (ECMWF) model 6-h forecast moisture profiles as a first guess and then adjusts the profiles based on SEVIRI-observed radiances in order to retrieve the TPW. At 1000 UTC, some high clouds can be seen in the HRV image in the northwestern portion of the black polygon, but otherwise the area is free of clouds.…”

Observations depuis l'orbite géostationnaire avec Meteosat troisième génération (MTG)

“…En outre, les observations d'IRS compléteront les produits des imageurs couramment utilisés pour surveiller l'instabilité atmosphérique (Koenig et de Coning, 2009) et l'initiation de la convection (Mecikalski et al, 2015).…”