- Monsoon is complex inter-hemispheric and inter oceanic phenomenon which makes the predictions very difficult.
- Tropical weather is highly variable as compared to temperate weather and is still not understood well.
- Complex topography of Indian subcontinent comprising loftiest mountains, expansive deserts; longest and deepest valleys surrounded by ocean from three sides make the monsoon highly variable in spatial and temporal contexts.
- Data insufficiency: The IMD collects weather data like temperature, humidity, wind and precipitation through 679 automatic weather stations, 550 surface observatories, 43 radiosonde or weather balloons, 24 radars and three satellites. However, this data is not enough given the size of India. However, more data is required to make the predictions accurate. Further, there are major data gaps, like those involving dust, aerosols, soil moisture and maritime conditions.
- Lack of infrastructure: The automatic weather stations are of substandard quality. They need to be calibrated and cleaned regularly, which doesn’t happen often. That affects the quality of data. Dynamical models require huge number of computations, for which supercomputers are required.
- Adoption of western models which are not fine-tuned as per the Indian needs.
- Impact of pollution: Increased concentration of aerosols in atmosphere tends to change the shape and characteristics of rain-bearing clouds, leading to extreme rainfall events but weakened monsoon rainfall.
NATIONAL MONSOON MISSION (NMM)
NMM aims to build models which are adept at predicting the monsoon. To set up a state-of-the-art coupled ocean-atmospheric climate model for:
- Improved prediction of monsoon rainfall on extended range to seasonal time scale (16 days to one season)
- Improved prediction of temperature, rainfall and extreme weather events on short to medium range time scale (up to 15 days) so that forecast skill gets quantitatively improved further for operational services of India Meteorological Department (IMD).
Targets were to develop a state of the art dynamical prediction system for monsoon rainfall (over Indian region) on different time scales (e.g., short range, medium range, extended range and seasonal time scales) with reasonably good prediction skill. Due to these government efforts statistical model along with dynamical model is improving the monsoon predictions.
Thus only if the monsoon forecast is improved drastically, India will be better prepared to face the uncertainties of monsoon and climate change. Also, it will help in effectively managing the disasters.