Statistical Climate Forecasting
The statistical forecasting methods are based on empirical relationships between rainfall over specific parts of the GHA and some global / regional/ local climate system indices. The major climate system indices that are operationally used at ICPAC include evolution of monsoons, medium and upper level winds, Madden-Julian Oscillation (MJO), Quasi Biennial Oscillation (QBO), El Niño Southern Oscillation, Indian Ocean dipole (IOD), tropical cyclones, sea surface temperature gradients among many others that have been derived from general circulation. Statistical downscaling of the global model outputs like GPCs are done using tools like CPT. ICPAC also runs Weather Research and Forecasting Model (WRF) for medium range forecasts; with Initial and Boundary conditions derived from GFS model. The forecasts products are mainly Tempearture, Precipitation and surface winds.
The statistical methods, however, cannot fully account for some of the rainfall variability. A lot of efforts must therefore be made to improve the skills of the forecasting systems. At the moment ICPAC is collaborating with a number of partners such as IRI, NCEP/CPC, UKMO, and KMA, among others to address climate forecasting and early warning challenges in the region.
The activities of the unit during the past eleven years( 2005-2015) have been:
- Documentation of the methods and associated applications.
- Provide forecasts on rainfall onset, cessation and distribution of dry/wet spells and temperature.
- Continuous verification of the forecasting products to assess the skill of the forecasts disseminated to the users.
- Diagnostic research to improve the forecasting products for various time scales.
- Develop pilot projects to assess and communicate successful use of forecasts.
- Improvement of statistical techniques on the downscaling of forecasting products to meet user requirements.
- Ensure user feedback is incorporated into forecast developments.
- Continue to improve the capacity of the member states on statistical and other new and emerging climate forecasting technologies.
- Enhance collaboration with other relevant regional and international centres engaged in climate forecasting and application services.
- Use of new tools and techniques like FIT, GIS, Geo-COF amongst others to improve seasonal forecasting.
- Use of Geo-Clim tool to grid station and satellite data.
Dynamical Climate Forecasting
The dynamical climate modelling methods used at ICPAC provide the evolutionary spatial and temporal evolutionary dynamics of weather and climate evolutions over the GHA region. Currently, ICPAC runs WRF model for medium range weather forecasts, PRECIS model for climate chnage and scenario development; and is in the process of setting up a Regional Spectral Model (RSM) for downscaling seasonal forecasts. The RSM model computation principle lies on the Fast Fourier Transform (FFT) technique which is its strength over grid point model techniques. The Initial and Boundary conditions are derived from NCEP GSM Reanalysis. The ultimate objective of the unit is to operationalize the running of the Regional Climate Models for downscaling of weather and climate at different time-scales. The Insituion is currently in the process of acquiring high perfomance computing cluster for modeling.
