Parameters and products to be mastered

Parameters and products to be mastered

This page lists the most efficient products on the MISVA site and provides information on how to use them, sometimes in combination with other products.

Parameters providing predictability

Numerical Weather Prediction (NWP) analyses and forecasts provide a wealth of information in the form of four-dimensional fields in space and time for all the variables of the models and their ensembles, which it is impossible for a forecaster to fully examine and analyse within the time constraints associated with producing a forecast.

The first approach is to analyse only certain fields for the variables and levels of most relevance for the geographical area and season under consideration. Thus, for West Africa during the monsoon season, 4 levels are recommended:

  1. the surface,
  2. 850 hPa for vorticies within the monsoon flux,
  3. the AEJ level (700-600 hPa)
  4. and the upper troposphere (200 hPa).

However, these levels are not always relevant, due to the high spatial and temporal variability of these fields, and in addition important structures and information can be found between these levels.

The other complementary approach proposed by the present MISVA site is to rely on new parameters derived from post-processing of data from NWP models, presenting less spatio-temporal variability, extracting the most important information and structures and providing predictability. Vertical integration over relevant layers or horizontal integration are widely used for this post-processing. 3 types of post-processing used by MISVA are presented below.

  1. Precipitable water (PW)
  2. Vertical integral on a layer
  3. Divergent and rotational components of the flow

Key products

The list below shows the most important products on the MISVA site, with illustrations of how to use them.

  2. Barotropic vortex and shear in the 925-600 hPa layer
  3. Maps of precipitable water and meridional transport
  4. Contribution of Equatorial Waves to anomalies of Velocity Potential at 200 hPa
  5. Hovmöller with Equatorial Wave filtering
  6. Indexes of intraseasonal activity (HL, AEW)