APPSC Current Affairs September 21st 2026

Why in News?

• India’s 51st Doppler Weather Radar was inaugurated at Sambalpur in Odisha on September 17, 2026. It will strengthen weather monitoring and early warnings across western Odisha and parts of neighbouring States. With this commissioning, Odisha now has three DWRs—at Sambalpur, Gopalpur and Paradip. India plans to install 40 more radars under Mission Mausam.

What is a Doppler Weather Radar?

A Doppler Weather Radar is a remote-sensing instrument used to detect precipitation and measure the movement of weather systems.

Unlike an ordinary radar, which mainly locates an object, a DWR provides information about both:

• The position and distance of atmospheric targets such as raindrops; and
• Their direction and speed of movement towards or away from the radar.

This makes DWRs particularly valuable for tracking thunderstorms, cyclones, cloud bands and intense rainfall.

What is the Doppler Effect?

• The Doppler Effect refers to the apparent change in the frequency of a wave when there is relative movement between its source and the observer.
• For example, the whistle of an approaching train appears to have a higher pitch because the sound waves are compressed. As the train moves away, the waves stretch and the pitch becomes lower.
• Doppler Weather Radars apply the same principle to reflected radio waves. The phenomenon is named after Christian Doppler, a 19th-century Austrian physicist.

How Does a Doppler Weather Radar Work?

A radar antenna transmits short pulses of radio waves into the atmosphere. When these waves encounter raindrops, ice particles, hailstones or clouds, part of their energy is scattered back towards the radar.

The returned signal provides the following information:

• Size and intensity: Larger or denser targets return more energy, helping estimate precipitation intensity.
• Distance: The time taken by a radio pulse to travel to the target and return indicates its distance from the radar.
• Direction of movement: A change in the phase or frequency of the returned signal reveals whether precipitation is moving towards or away from the radar.
• Speed: The size of the phase shift helps calculate the radial velocity of the target.

Radar observations are updated approximately every 10 minutes, enabling forecasters to monitor the formation, direction and changing intensity of weather systems almost in real time.

According to the US National Weather Service, a DWR transmits signals for only a little over seven seconds in an hour and spends the remaining 59 minutes and 53 seconds receiving and analysing returned signals.

Types of Doppler Weather Radars Used in India

The India Meteorological Department (IMD) commonly uses three frequency bands:

Together, these radars track cloud bands and weather systems and estimate rainfall over a coverage area of about 500 km, depending on radar type and atmospheric conditions.

Why are Doppler Weather Radars Important?

Accurate Weather Monitoring

• DWRs provide high-resolution information on the location, movement and intensity of precipitation. This improves nowcasting, or very short-range forecasting of rapidly developing weather.

Early Warning of Extreme Events

They help identify and track:

• Cyclones and associated rainfall
• Thunderstorms
• Lightning-producing systems
• Cloudbursts and intense rainfall
• Hailstorms
• Sudden changes in wind patterns

Disaster-Risk Reduction

• Timely radar information enables governments to issue warnings, evacuate vulnerable populations and prepare emergency services before hazardous weather reaches populated areas.

Sectoral Benefits

Reliable forecasts support decision-making in:

• Agriculture: Crop planning, irrigation and harvesting
• Aviation: Safer flight operations
• Defence: Operational planning
• Water resources: Reservoir and flood management
• Energy: Demand and renewable-energy forecasting
• Urban governance: Drainage and transport management
• Tourism and fisheries: Weather-based safety advisories

Sambalpur Doppler Weather Radar

The commissioning of the radar at Sambalpur expands India’s meteorological observation infrastructure.

Its principal benefits include:

• Improved monitoring of thunderstorms, lightning and heavy rainfall in western Odisha.
• Better meteorological data for adjoining areas of southern Jharkhand, northern Chhattisgarh, northern Andhra Pradesh and West Bengal.
• Stronger regional early-warning systems in areas vulnerable to extreme weather.
• Improved coordination between weather agencies and disaster-management authorities.

With Sambalpur, the national DWR network has increased to 51 radars.

Mission Mausam

About the Mission

• Mission Mausam was launched on January 14, 2025, during celebrations marking the 150th foundation day of the India Meteorological Department.
• The Union Cabinet had approved the Mission in September 2024 with an allocation of ₹2,000 crore for two years. Its broader objective is to make India a “weather-ready” and “climate-smart” nation.

Implementing Institutions

The Mission is primarily implemented by three institutions under the Ministry of Earth Sciences:

• India Meteorological Department
• Indian Institute of Tropical Meteorology
• National Centre for Medium-Range Weather Forecasting

They are supported by other institutions, including:

• Indian National Centre for Ocean Information Services
• National Centre for Polar and Ocean Research
• National Institute of Ocean Technology

Major Components

Mission Mausam provides for:

• Deployment of next-generation radars and satellite systems with advanced sensors.
• Installation of 40 additional Doppler Weather Radars.
• Use of high-performance supercomputers.
• Development of improved Earth-system and weather models.
• A GIS-based automated decision-support system for real-time data sharing.
• Expansion of research and capacity in atmospheric sciences, weather surveillance, forecasting and weather management.

Areas Covered

The Mission seeks to improve forecasts relating to:

• Monsoon behaviour
• Cyclones and extreme weather
• Air quality
• Rainfall, hail, fog and lightning
• Weather and climate information across different spatial and temporal scales

It also seeks to strengthen research into weather interventions, including the possibility of enhancing or suppressing rainfall, hail and fog under suitable conditions.

Significance for India

India is highly vulnerable to cyclones, floods, lightning, heatwaves and extreme rainfall. Rapid urbanisation and climate change have increased the exposure of people, infrastructure and economic activity to such events.

An expanded DWR network under Mission Mausam can:

• Reduce the loss of life through timely warnings.
• Improve location-specific forecasts.
• strengthen preparedness among States and local bodies.
• Support climate-resilient agriculture and infrastructure.
• Enable real-time sharing of weather information.
• Improve the delivery of warnings to citizens and last-mile users.

Thus, weather radars are not merely scientific instruments; they form a vital part of India’s disaster-management and climate-adaptation infrastructure.

Challenges

• Gaps in Radar Coverage: Mountainous, coastal and remote regions may not receive uniform radar coverage, reducing the accuracy of local forecasts.
• Terrain-Related Limitations: Hills, buildings and other physical barriers can block radar signals and create observation gaps.
• High Installation and Maintenance Costs: Doppler Weather Radars require significant investment, regular calibration, technical maintenance and uninterrupted power supply.
• Shortage of Skilled Personnel: Trained meteorologists, radar engineers and data scientists are needed to interpret large volumes of weather data accurately.
• Integration of Weather Data: Radar information must be effectively combined with data from satellites, ocean buoys, automatic weather stations and ground observatories.
• Forecasting Localised Events: Sudden cloudbursts, lightning and small-scale thunderstorms can develop rapidly, making precise prediction difficult.
• Last-Mile Communication Gaps: Accurate forecasts may not save lives if warnings fail to reach farmers, fishers, local authorities and vulnerable communities on time.
• Impact of Climate Change: Changing rainfall patterns and increasing extreme-weather events make weather prediction more complex.

Way Forward

• Expand the Radar Network: Install the proposed Doppler Weather Radars under Mission Mausam, with priority given to disaster-prone and poorly covered regions.
• Adopt Multi-Source Forecasting: Integrate radar, satellite, oceanic and ground-based observations to improve forecast accuracy.
• Strengthen Technical Capacity: Train more meteorologists, engineers and data specialists in radar operation, maintenance and weather modelling.
• Improve Impact-Based Forecasting: Warnings should explain not only the expected weather event but also its likely effects on people, agriculture, transport and infrastructure.
• Ensure Last-Mile Connectivity: Disseminate alerts through mobile applications, SMS, local administrations, community radio and regional-language communication networks.
• Promote Institutional Coordination: Strengthen coordination among the IMD, disaster-management authorities, State governments and local bodies.
• Use Advanced Technologies: Apply artificial intelligence, high-performance computing, GIS and improved Earth-system models for faster and more location-specific forecasting.
• Regularly Evaluate Warning Systems: Conduct periodic reviews to assess whether forecasts are timely, accurate and accessible to vulnerable communities.

Conclusion

The Sambalpur Doppler Weather Radar represents an important expansion of India’s weather-observation network. Combined with Mission Mausam, it can strengthen forecasting, disaster preparedness and climate-resilient planning. However, technological capability must be supported by reliable maintenance, institutional coordination and effective last-mile communication. A comprehensive early-warning system will help protect lives, livelihoods and infrastructure while advancing climate-smart governance.