Commissioning Of Polarimetric Doppler Weather Radars

Policy Update
Sivapriya CB

Background

Polarized Doppler Weather Radars (DWRs) are forecasting systems that use both horizontal and vertical polarization to gather detailed information about precipitation. The operating frequencies of DWRs can range from S-band to X-band, depending on terrain, application, and coverage range. Commissioning PDWRs is an initiative by the Ministry of Earth Sciences (MoES) and is part of one of the eight sub-schemes of ACROSS (Atmospheric & Climate Research-Modelling Observing Systems & Services), aiming to modernize weather forecasting infrastructure.

Its primary goal is to expand the DWR network to address existing gaps in India’s meteorological observation system by installing eleven C-Band dual-polarized DWRs and creating multiple overlapping configurations of modern DWRs. This effort seeks to achieve complete radar coverage and improve the accuracy of weather forecasts across India.

Polarized DWRs serve several purposes, including providing timely warnings of weather abnormalities such as storms and monsoon depressions, supporting nowcasting, and differentiating between supercell storms and typical storms. Furthermore, the dual-polarimetric capability allows for collecting additional data on hydrometers and their quantities within clouds, among other applications.

Objectives

Improve the spatial and temporal density of the radar observational network over the regions with large data gaps in the country.
Better investigation, monitoring, and tracking of tropical cyclones during pre-monsoon and post-monsoon seasons in the subcontinent.
Monitoring and tracking of monsoon depressions and lows across the subcontinent and improvement in the current understanding of the physical processes associated with tropical cyclones and monsoon systems, and a better understanding of convective activity.

Functioning

The Mission Mausam, launched by the Ministry of Earth Sciences (MoES) and India Meteorological Department (IMD), operates with the main focus of augmenting the network of Doppler weather radars in India for accurate forecasting of weather events.

Currently, there are 39 DWRs across the country to foster real-time monitoring of weather events. An investment of INR 2000 crores (in total) has been approved for Mission Mausam over two years by the Union Cabinet, through which tentative locations for installing 87 more DWRs are being planned.

Consequently, IMD has decided on the tentative locations across the country, considering the existing coverage gaps in the radar network. The C-Band DWRs (operating on lower frequencies and longer wavelengths) are tentatively being planned to be at Raipur, Mangalore, Ranchi, Lakshadweep, Malda, Aurangabad, Balasore, Sambalpur, Ahmedabad, Bengaluru, Rupsi & Port Blair.

Apart from these, expansion also includes 12 X-Band DWRs (operating on higher frequencies and shorter wavelengths) across the country, 10 X-Band DWRs specifically for the North East Region, so that the entire country is covered.

Performance And Impact

According to the PIB, IMD has inaugurated 4 polarimetric radars across the country in January 2022. They are as follows:

X-Band DWR at Ayanagar (Delhi): This DWR was built indigenously with technology developed using the latest solid-state power amplifier transmitter at the IMD office. The radar will expand the weather monitoring competencies of IMD for the NCR region by using the dual polarisation technology.
X-Band DWR at Leh: This radar is at the highest altitude in India and will provide important information by detecting and monitoring severe weather conditions in the Ladakh region, and covers an area of 100km around Leh.
C-Band DWR at Mumbai: The radar at Veravali(East Andheri, Mumbai) is a joint effort of IMD and ISRO to provide improved information regarding rainfall estimates and hydrometer classification, potentially improving forecasting capabilities.
X-Band DWR at Chennai: This polarized DWR is at the campus of the National Institute of Ocean Technology and covers an area with a radius of 150 km around Chennai.

Notably, all four DWRs were indigenously developed under the Make in India initiative.

Concerning Agricultural Weather Services (AWS), the following progress has been made in April 2022:

At present, experimental block-level weather forecasts and Agromet Advisory Service Bulletins are issued for around 3000 blocks spanning over 355 districts in the country.
Around 198 AWS are installed in Krishi Vigyan Kendras (KVKs).

A 2025 PIB review noted the progress of Mission Mausam, which states that 73 Doppler Weather Radars will be operational by 2025-26 and 126 by 2026, increasing the capabilities to track extreme weather events and benefit the general public.

Supply orders for 34 DWRs have already been placed, and additionally, the Expenditure Finance Committee (EFC) has approved the procurement of 53 more DWRs.

Bharat Electronics Limited (BEL) has developed S-Band Polarimetric DWRs as a collaborative effort that involves IMD, ISRO, and NAL under a technology transfer as a part of the Make in India initiative in 2018. This radar provides long-range weather surveillance up to 500 km and is capable of detecting and estimating the parameters of cyclones and other severe weather conditions. It can also forecast weather events to foster preventive measures and avoid loss of life and property.

Doppler weather radars now monitor clouds, winds, and classification of cloud forms every 10 minutes without interruption, according to the PIB report.

Apart from this, a 2019 NCAER study regarding agriculture estimated an extra Rs 12500 per household in rainfed areas and a total agrarian gain of Rs 13331 crore per year, highlighting the improved contribution of forecast systems.

In disaster management, from 2019-2023, IMD forecast accuracy improved by 40-50% because of an augmented radar network across the country. This also helps with grid stability in energy management by providing accurate short-term predictions of renewable energy generation and weather conditions.

Emerging Issues

There are a few problems with the execution of the policy that are discussed below:

Eight states currently depend on DWRs installed in neighbouring states – Chhattisgarh, Haryana, Jharkhand, Karnataka, Manipur, Mizoram, Nagaland, and Sikkim. This calls for quicker augmentation of the radar network to ensure timely information on extreme weather events.
Maintenance Issues: The S-Band DWR at the Port Trust Centenary building in Chennai was imported from Germany in 2002 and was facing problems in the mechanical system due to wear and tear without proper maintenance. The spare parts for replacement are not easily available and are operated on a need basis rather than regularly. Maintenance or calibration issues also arise if they are done irregularly, which will degrade radar capabilities. This can be rectified by adopting regular, stringent calibration of radars at fixed intervals to make the data more accurate and consistent.
Boost R&D: Considerable progress has been made by developing indigenous production of DWRs under the Make in India Scheme, which calls for more investment and support to boost research and development to avoid foreign dependency and reduce expenses. This can be done by developing a separate division for radar research and training, which in turn will provide better opportunities towards product development and capacity building while bridging the technology gaps.

Way Forward

The Polarimetric DWR initiative aims to augment the radar network across the country for accurate weather forecasting and reducing the risk of disasters. Data shows that this policy has helped in increasing forecast accuracy by 40-50% and has increased total agrarian gain while also fostering indigenous technology.

However, challenges remain in certain aspects of network coverage and maintenance. Overall, the policy must move towards complete national radar coverage quickly, invest in indigenous technology and local manufacturing, and strengthen maintenance standards. This policy has become the foundation for a climate-ready India with accurate forecasting to realise long-term socio-economic and environmental gains.

References

ANNUAL REPORT 2022 INDIA METEOROLOGICAL DEPARTMENT (MINISTRY OF EARTH SCIENCES) Annual Report 2022
BHAT, G. S., VIVEKANANDAN, J., & PRADHAN, D. (2025). Evolution of Radar Meteorology in India and the latest trends. MAUSAM, 76(1), 55–64. https://doi.org/10.54302/mausam.v76i1.6497
Commissioning of Polarimetric Doppler Weather Radars (DWRs) | India Science, Technology & Innovation – ISTI Portal. (2024). Retrieved June 27, 2025, https://www.indiascienceandtechnology.gov.in/programme-schemes/research-and-development/commissioning-polarimetric-doppler-weather-radars-dwrs
Commissioning of Polarimetric Doppler Weather Radars (DWRs) | Ministry of Earth Science, Government of India
Deep, K., Singh, R., Yadav, K., Sai Krishnan, L., Cdr, N., & Rawat. (2021). Analysis of three unusual severe weather events over Delhi during May-June 2018 using Dual-Pol Doppler Weather Radar and GNSS data. MAUSAM, 72(4), 719–738. https://doi.org/10.54302/mausam.v72i4.3543
GOVERNMENT OF INDIA MINISTRY OF EARTH SCIENCES RAJYA SABHA UNSTARRED QUESTION No. 3223 TO BE ANSWERED ON 31st March 2022 WEATHER
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