The best way to get to grip with the MISVA site, and to master the use and interpretation of its products, is to work on case studies. To this end, a series of interesting historical cases have been selected and analysed so that they can be made available on different media.
1. Case studies used in Handbook
When the “Forecaster’s Handbook” was being written, several case studies were used to illustrate typical situations: the conceptual models in the Handbook, the WASA-F method (Chapter 11) and various diagnostics, most of which are available daily on the MISVA website. The table below lists them with some information (date, main characteristics, documentation).
| Case number | Date | Main characteristics | Handbook illustrations | Documentation |
| CS01 | 2012 01-10/08 | Strong AEW case with Breaking | pp 104; 141-143 | handbook case study (umr-cnrm.fr) |
| CS02 | 2012 12-16/08 | Archetype of AEW | pp 137-140; 196; 203-208; 716-733 | handbook case study (umr-cnrm.fr) |
| CS03 | 2012 15-19/10 | Mid latitude dry air intrusion case | pp 711-714 | handbook case study (umr-cnrm.fr) |
| CS04 | 2009 28/08 to 02/09 | THORPEX-Africa Ouagadougou Flood AEW breaking – extrem event | pp 104; 141-143 Fig. 9.41 | Lafore et al. 2017, Beucher et al. 2019 |
| CS05 | 2012 15-18/03 | Dust case I Libya high pressure | Figure 5.18a pp 343-344 | handbook case study (umr-cnrm.fr) |
| CS06 | 2012 04-07/02 | Dust case II Azores high pressure | Figure 5.18b pp 343-344 | handbook case study (umr-cnrm.fr) |
| CS07 | 2012 13/02 | Gust + flood event Nigeria | ||
| CS8 | 2011 22-28/10 | Ghana Flood ITCZ over Guinea Gulf | ||
| CS9 | 2012 24-26/08 | Dakar Flood | ||
| CS10 | 2010 09-12/06 | Dust case III Haboob over Niger | PP 349-350 | |
| CS11 | 2006 30/07 – 02/08 | AMMA case MCS and AEW over WA | ||
| CS12 | 2009 25-29/05 | Mid season case Dynamic PV anomaly over Mali leading to a squall line. Convective activity over Chad. | ||
| CS13 | 2011 09-12/01 | Winter case Harmattan over Guinea Gulf, ITD is no more defined as it goes over sea. | ||
| CS14 | 2014 27/09 | Courant de densité | pp 208-210 | |
| AMMA | 2006 23-30/07 | AEW + monsoon burst | Barthe et al. 2010 Beucher et al. 2013 | |
| 2014 01-10/09 | Coastal Development of AEWs : Northern and Southern Vortex | pp 143-145 |
2. Case Studies available on the website “Handbook case study”
- Bilingual website handbook case study (umr-cnrm.fr)
- CS01: 1-10 August 2012 – Life cycle, structure and passage over West Africa of a train of African Easterly Waves. It resulted in a breaking of the AEJ.
- CS02: 13-16 August 2012 – Life cycle, structure and passage over West Africa of a canonical African Easterly Wave (AEW)
- CS05: 15-18 March 2012 – Dust Storm driven by the Libya High pressure
- Documented cases (Files are available), but not yet available on the site
- CS03: 15-19 Octobre 2012 – Mid latitude dry air intrusion case
- CS04: 28 August 3 September 2009 – THORPEX-Africa Ouagadougou Flood (1st Sept), with an AEW breaking. Studied in a series of 2 papers (Lafore et al. 2017; Beucher et al. 2019)
- CS06: 15-18 mars 2012 – Dust Storm driven by the Azores High pressure
3. Case Studies identified during weekly briefings
During the weekly briefings, each of the countries involved selects key events that could merit a more in-depth analysis to gain a better understanding of the situation and assess its predictability. A summary table lists these potential case studies in the table (below for 2021) giving the main characteristics of these events for each monsoon season (date, observed rainfall, location, type, forcing).
This documentation uses some of these cases from 2021 to illustrate the use of certain products, for example the case of 30-31 August 2021 in Senegal to visualise a vortex using the product Barotropic vortex and shear on the 925-600 hPa layer Tourbillon barotrope et cisaillement sur la couche 925-600 hPa – Misva (aeris-data.fr), a vortex which was at the origin of cyclone Larry (31 August to 11 September 2021).
References
Beucher F, Lafore J-P, Chapelon N. Simulation and analysis of the moist vortex associated with the extreme rain event of Ouagadougou in 2009. Q J R Meteorol Soc.2020;146:86–104. https://doi.org/10.1002/qj.3645
Lafore, J.-P., Beucher, F., Peyrillé, P., Diongue-Niang, A., Chapelon, N., Bouniol, D., Caniaux, G., Favot, F., Ferry, F., Guichard, F., Poan, E., Roehrig, R. and Vischel., T. (2017a) A multi-scale analysis of the extreme rain event of Ouagadougou in 2009. Quarterly Journal of the Royal Meteorological Society, 143(709), 3094–3109. https://doi.org/10.1002/qj.3165.