Warning and forecasting of Cyclones
A tropical cyclone in combination with local tides and local coastal configuration gives rise to a storm surge that makes coastal areas vulnerable to flooding, erosion of beaches, loss of soil fertility due to saline intrusion along with a heavy risk of damage to structures.
Cyclones with strong winds cause damage to structures, loss of power and communication, injuries and loss of life along with destruction of crops, vegetation and live stock. In such instances, there is also a risk of contamination of water supply system and land subsidence coupled with the risk of flooding of inland areas. A block diagram of the early warning system being used by the IMD is shown below.
INSERT IMAGE!
LAFS - Limited area Analysis and Forecasting System
NWP - Numerical Weather Prediction
NCMRWF - National Centre for Medium Range Weather Forecasting
RTH - Regional Telecom Hub
The Observation system consists of:
-Conventional Observation Network
-Automatic Weather Station
-Buoy/Ship observations
-Cyclone Detection Radar
-Doppler Weather Radar
-Satellites
Satellite Observations
-Images in all three channels
-Outgoing longwave radiation
-Atmospheric motion vectors
-Quantitative precipitation estimates
-Sea Surface Temperatures
-Products derived fro CCD data
Tropical Cyclonic Track Forecasting
-Method based on climatology (Analog)
-Methods based on persistence and climatology
-Synoptic methods - Empirical techniques
-Satellite techniques
-Statistical techniques (Chaos theory & generic algorithm developed by SAC Ahmedabad)
-Analog techniques
-NWP models
-Operational (consensus) forecast
- Scientific and technological advances are translated into effectiveness of tropical cyclone warnings
- The forecasters blend scientifically based conceptual models, meteorological datasets, technology and expertise towards the goal of providing clear, concise, useful and relevant warning information to the public in a timely and effective manner.
- The basic values and principles are described in the operational guidelines set by the IMD
- Existing Numerical Weather Prediction (NWP) models for cyclone forecasting are:
- Global model of NCMRWF (T254)
- Regional model (LAM & QLM)
- Meso-scale model (MM5 & WRF)
- International models used in IMD:
- ECMWF - European Centre for Medium-range Weather Forecasting
- UKMO - United Kingdom Met Office
- JMA - Japan Meteorological Agency
- COLA anomaly coupled model
LAM - Limited Area Model
QLM - Quasi Lagrangian Model
WRF - Weather Research and Forecasting
MM5 - Meso-scale Model
A good warning model should be:
- Simple
- Easy to understand
- Able to trigger organised responses from the government
- Able to create orderly collective responses of the public to minimize loss of life and damage to property
