MISVA
Monitoring and forecast of IntraSeasonal Variability over Africa
MISVA – Monitoring and forecast of IntraSeasonal Variability over Africa – is a joint research/operational collaboration between Meteo-France and the West African weather forecasting services: ANACIM (Senegal), Mali Meteo, ANAM Burkina Faso, MND Niger, ANAM Chad and MND Togo. This action aims at a better understanding and forecasting of rainfall, especially extreme rainfall, in West Africa at synoptic to sub-seasonal scales.
To this end, a series of state-of-the-art forecasting models, satellite products and in situ observations are developed by the CNRM and updated daily.
Available products:
The following products can be accessed by clicking on the left browser :
- Bulletins: daily summary (daily_summary), ANASYGs (WASA) and weekly briefing summary
- Observation products: based on IMERG satellite products for rainfall, NOAA for RLO, Reynolds for SST and ANACIM rain gauges. They are available at daily, weekly and monthly time steps. Onset indices, hovmollers are available.
- Sub-seasonal forecast: products from ECMWF ensemble forecasts from D0 to D+45 at 0.75×0.75 resolution, at daily and weekly time steps.
- Synoptic forecast: products from the ECMWF deterministic model at 0.75×0.75, 6h or daily time step
Methods
The methodology and products at the heart of MISVA are based on a few concepts detailed in the documentation tab, in particular the “Getting started with MISVA” tab. Two methodological aspects are frequently used:
We consider the raw fields and their intraseasonal anomalies, simply called anomalies here, which are the difference between the raw field and the smoothed daily climatological annual cycle (more details here). The anomaly work allows to isolate the specificity of the day or week considered.
We work on the rainfall variability mechanisms (African easterly waves, equatorial waves, thermal depression) using parameters and products that provide predictability. The main ones are the precipitable water (PW), the meridional wind (Mean-Vwind) and the averaged parameters in the low layers, including the vortex (LowLevel-Diag) and the velocity potential and current function at 200 and 700 hPa.