Warning and forecasting of Cyclones

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.

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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:

1. Simple
2. Easy to understand
3. Able to trigger organised responses from the government
4. Able to create orderly collective responses of the public to minimize loss of life and damage to property

Warning and forecasting of Earthquakes

Warning and forecasting of Earthquakes

The Ministry of Earth System Science - National Centre for Seismology (MoES-NCS) maintains a national seismological network consisting of 42 digital seismographs stations to measure earthquake magnitude and monitor earthquake activity in and around the Indian region. Additionally 78 new digital seismographs have been installed recently. The ground motion data recorded by the instrument system are used for the estimation of magnitude and other earthquake parameters. However, there is no scientific technique available anywhere in the world to forecast or predict the occurrence of earthquake with reasonable degree of accuracy  with regard to space, time and magnitude.

Loss of life and damage to property due to earthquakes could be reduced through proper planning and implementation of pre- and post- disaster preparedness and management strategies by the government. Guidelines have been published by the Bureau of Indian Standards (BIS) and Building Materials and Technology Promotion Council (BMTPC) for the design of earthquake resistant structures to minimise the loss of life and damage to property caused by earthquakes. Government agencies and academic institutions are currently engaged in the following activities for warning and forecasting earthquakes.

• Up-gradation and digitization of topographic maps with contour interval of 0.5m by Survey of India (SOI) and National Remote Sensing Centre (NRSC)
• Sharing of seismic data being collected by IMD with other departments
• Deployment and augmentation of observing systems such as GPS, bore hole sensors, multi-parametric observing systems, etc at identified locations for better understanding of physical processes associated with earthquakes, active fault mapping in addition to the existing conventional weak and strong motion observing systems.
• Creation of a modern test and maintenance facility for testing and upkeep or rectification of existing sophisticated equipment and seismological instruments such as broadband sensors, SMAs, digitizers and communication systems.
• Strengthening or augmentation of the existing data centre facility of IMD.
• Raster scanning and vector digitization of seismic analog charts at seismological observatory. Raster scanning of remaining significant historical seismograms, their vector digitization and archival in electronic media.
• Analysis of seismological and collateral geophysical data in near real-time
• R & D programs in collaboration with other leading countries in development of earthquake prediction and forecasting methods.
• Establishment of additional heavy mass vibration laboratories
• Development of GIS based hazard and vulnerability database or digitized maps
• Innovative earthquake resistant construction technologies for new and retrofitting of existing buildings
• Monitoring earthquakes and conducting research for earthquake instrumentation
• Real-time monitoring for occurrence of earthquakes
• Setting-up earthquake scenarios for major urban high hazard areas
• Mapping of all faults

Earthquake instrumentation and monitoring:

India has more than two hundred earthquake monitoring stations which are mainly located in high hazard areas along the Himalayas and in the north-east. In order to identify the major earthquake sources and their activity rates, dense networks of earthquake monitoring stations are required. Each such network consists of at least 90 strong motion instruments and 10 broad band instruments. These instruments are used to identify the seismic source, activity rate, strain build-up, determination of ground motion equations and for updating earthquake hazard map of the region.

Real-time earthquake occurrence monitoring:

A network of earthquake monitoring stations is used to assess the size, location, depth and wave propagation parameters of earthquake events in realtime.

Warning and forecasting of Tsunami

Warning and forecasting of Tsunami

The Indian National Center for Ocean Information Services (INCOIS) has the mandate for detecting tsunamigenic earthquakes occurring in the Indian Ocean as well as in the global oceans within ten minutes of occurrence of the earthquake and disseminating the tsunami related advisories to the concerned authorities through email, fax, GTS and website. The India Tsunami Early Warning Centre (ITEWC) established at INCOIS has the latest scientific  techniques to provide early warnings  for an impending tsunami to all countries in the Indian ocean region. Indian Tsunami Early Warning System comprises of a real-time seismic monitoring network of broadband seismic stations. INCOIS also has a real-time sea-level network with seven tsunami buoys in the open ocean and 35 tide gauges at different locations on the coast to monitor the tsunami waves. In addition, INCOIS also takes the help of numerical model to assess the tsunami potential at different locations on the coast. ITEWC is also receiving data in real time from 350 seismic stations, 50 tsunami buoys and 300 tidal gauges established in the Indian as well as the other oceans by other countries and international agencies. The operational forecasting of tropical cyclones is the mandate of the IMD. Intergovernmental Oceanographic Commission (IOC) of UNESCO has designated ITEWC as the Tsunami Service Provider (TSP) for the entire Indian Ocean Region. Since 2012, ITEWC is providing tsunami advisories and related services to about 25 countries.
A High Performance Computer (HPC) system named 'Mihir' was inaugurated at the NCMRWF. This facility will greatly improve India's capacity in weather forecasting. It is India's largest HPC facility in terms of peak capacity and performance. Mihir's resources can be used by weather and climate community to provide tsunami forecasts with greater lead time.

Warning and early forecasting of droughts

Drought is a normal recurrent feature of climate and occurs in all climatic regions and is usually characterized in terms of its spatial extension, intensity and duration. Conditions of drought appear when the rainfall is deficient in relation to the statistical multi-year average for a region, over an extended period of a season or year or even more. It is slow on-set and hence difficult to determine the beginning and end. It requires continuous monitoring of climate and water supply indicators. Impacts are difficult to quantify, are cumulative and effects magnify when events continue from one season to another. Impacts of droughts may be direct or indirect.
Direct impacts include:
-Reduced agricultural production
-Increased fire hazard
-Depleted water levels
-Damage to wildlife and fish habitats
-Higher livestock & wildlife mortality
Indirect impacts include:
-Social impacts
-Economic impacts and
-Environmental impacts

Drought monitoring can be carried out using:

• Monitoring and early warning system
• Key drought indicators
• Developing a composite index and
• Drought monitoring checklist

Early warning system:

• Receive forecasts, early warning and advisories from scientific institutions
• Monitor key indices amd
• Develop composite index of various drought indicators

1. IMD is the designated agency for providing drought early warning and forecasting. IMD monitors agricultural drought every two weeks on a real-time basis during main crop seasons (Kharif and Rabi) of India. An Aridity Anomaly Index based on the lines of Thronthwaite's concept is used to monitor the incidence, spread, intensification and recession of drought. The Drought Research Unit at IMD Pune, provides crop yield forecasts using pre-harvest crop yield forecasting models and issues forecasts for Kharif and Rabi crops based on agro-meteorological models.
2. The National Centre for Medium Range Weather Forecasting (NCMRWF) in collaboration with IMD, Indian Council for Agricultural Research (ICAR), State Agricultural Universities (SAU) provides agro-climatic zones to the farming community based on location specific medium range weather forecasts. The Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad and the All India Coordinated Research Projects on Agrimeteorology and Dryland Agriculture (AICRPAM & AICRPDA) each have 25 centers across SAUs across the country and take part in drought studies pertaining to assessment, mitigation, risk transfer and development of Decision Support Software (DSS) for drought prone states. 
3. The ministry of earth sciences in collaboration with ICAR has set-up 89 centers for short and medium range monitoring and forecasting of weather.
4. The National Agricultural Drought Assessment and Monitoring System (NADAMS) developed by department of space for the department of agriculture primarily monitors the vegetation through National Oceanic and Atmospheric Agency's (NOAA) Advanced Very High Resolution Radiometer (AVHRR) data. Drought assessment is based on a comparative evaluation of satellite observed green vegetation cover of a district in any time period with that of any similar period in previous years. This comparative evaluation helps in fixing current season in the scale of historical agricultural situations.

Forecasting and warning of landslides

Landslide monitoring and early warning systems for landslide occurrence and prediction

An integrated wireless sensor network system for real-time monitoring and early warning of landslides has been carried-out in India. It consists of Intelligent Wireless Probes (IWP) to capture relevant landslide triggering parameters. The network of IWPs is used to derive the local or regional contribution of geological, hydrological and meteorological factors towards the initiation of a potentially imminent landslide. This heterogeneous sensor system provides the capability for gathering real-time context aware data to understand the dynamic variability in landslide risk. The system enhances the reliability of landslide warning, reduced false alarm rate and provides the capability to issue warnings at local and regional levels. An early warning system is an effective measure to reduce the damage caused by landslides by facilitating timely evacuation of residents from a land-slide prone area. Early detection of landslide triggering across a broad range of natural terrain types can be accomplished by monitoring rainfall and the physical property changes in soils in real-time or near real-time. This can be conducted by installing real-time monitoring system to observe physical property changes in soils in a valley during rainfall events. Laboratory experiments have shown that volumetric content of water is a prime parameter to evaluate the stability of a slope. Hence, landslide monitoring can be based on volumetric water content and its changes over time over shallow soil depths. It has been shown that a high amount of rainfall combined with a high gradient of volumetric water content induces a slope failure. This suggests a threshold value of volumetric water that separates conditions for slope stability and slope failure. Hence this threshold value can be used as an early warning system for landslides.

Warning & forecasting of floods

Indian Space Research Organisation (ISRO) is working on systems to forecast natural disasters that could be used as input by states / disaster management agencies. ISRO is carrying out studies to facilitate best use of satellite derived information to develop methodologies for forecasting natural disasters. Some of the methodologies used are listed below:

1. ISRO has developed methodologies for forecasting cyclone formation, its track and intensity using satellite based observation and this technique has been transferred to IMD who is mandated for cyclone forecast
2. Flood Early Warning Systems: The North Eastern Space Applications Center (NESAC) of ISRO has developed the Flood Early Warning System (FLEWS) as a research and development project in Assam state in association with Assam State Disaster Management Authority (ASDMA). This model in being used in all 25 flood prone districts of Assam. Another model for forecasting floods in Godavari flood plains in Andhra Pradesh is developed by National Remote Sensing Centre (NRSC) of ISRO. The methodology is being used by Central Water Commission (CWC). ISRO is developing similar systems for Krishna, Brahmani-Baitarani, Ghagra, Gandak and Kosi rivers.
3. Space Applications Center (SAC) of ISRO has developed a model for heavy rainfall/cloud burst alerts, which is experimentally carried for Indian region. The information is made available on ISROs Meteorological and Oceanographic Satellite Data Archival Centre (MOSDAC)
4. Rainfall triggered landslide alerts for the Uttarakhand region has been developed as an experimental early warning system for use along the pilgrimage route corridors leading to Gangotri, Badrinath and Kedarnath as well as along the Pithorgarh-Malpa route in Uttarakhand. The forewarning is generated based on the statistical relation between the terrain (geological, morphological) and temporal (primarily long term rainfall events) factors 
5. ISRO has developed experimental methodologies for early warning extreme weather events such as heat wave using Numerical Weather Predictions (NWP). The information derived is being made available on the MOSDAC website.

ISRO has realised two satellite missions:

1. Meghatropiques launched in October 2011 and
2. Saral launched in Febuary 2013 in collaboration with French National Space Agency (CNES)

Currently ISRO is working with National Aeronautics and Space Administration (NASA), for a joint realisation of a satellite mission called NASA-ISRO Synthetic Aperture Radar (NISAR) to be launched in 2020-21. Fund allocation for Meghatropiques is 81.6 crore, SARAL is 73.75 crore and for NISAR is 513 crore.

Disaster Management & Mitigation - UNIT-V

Risk and vulnerability to disaster
Disaster mitigation and management options - warning and forecasting