Key Details
The 2026 WMO–ITU handbook, Use of Radio Spectrum for Meteorology: Weather, Climate, Water and Related Environmental Applications, maps the frequencies used to observe environmental conditions, transmit measurements and produce forecasts. The handbook also sets out how to assess harmful interference from other radio services.
System | Why It Needs Radio Spectrum |
|---|---|
Weather radars | Detect rainfall and track storms using weak signals reflected back to the radar. |
Radiosondes | Transmit atmospheric measurements from instruments carried by weather balloons. |
Meteorological satellites | Observe conditions over large areas and send data to ground stations. |
Passive satellite sensors | Detect faint natural emissions at frequencies linked to particular atmospheric properties. |
Lightning and space-weather instruments | Use radio signals to locate lightning or observe solar and atmospheric activity. |
A Forecast Relies on More Than One Radio Link
Weather services combine observations from the ground, atmosphere and space, then exchange those data for analysis and forecasting. Interference can affect either the measurement itself or the transmission of its data. Weather radars, for example, need sufficiently quiet frequencies to detect weak returns from rain and storms—information used in severe-weather and flash-flood warnings.
Some Satellite Measurements Cannot Move to Another Frequency
Passive sensors measure extremely weak radiation emitted naturally by the Earth and atmosphere. Particular frequencies reveal particular properties, such as atmospheric temperature or water vapour. Because those frequencies are determined by physics, shifting a sensor to a different band is not always a solution to interference. Consistent access also matters for comparing climate observations over time.
Spectrum Decisions Shape Observation Capacity
The handbook brings together the frequencies used by meteorological systems, criteria for judging interference and the possible effects on data and warnings. It reflects growing competition for radio spectrum while explaining why weather and environmental measurements need to be considered in allocation and sharing decisions. The WMO and ITU issued a separate call to protect these services when the handbook was released in September 2026.
Policy Relevance
For India, spectrum planning is also an early-warning issue. The practical test is whether IMD’s requirements for radars and weather observations, and ISRO’s requirements for satellite sensing and data links, are assessed when DoT considers competing uses of relevant bands. Protection needs to address interference from nearby frequencies as well as transmissions within an allocated band.
The handbook does not assess the performance of India’s spectrum arrangements. It does identify what such an assessment must safeguard: usable observations for forecasts and warnings, and the continuity of measurements needed to track climate change. Its specific India references are limited to research instruments used for space-weather observation.
Follow the Full Handbook Here: WMO–ITU, Use of Radio Spectrum for Meteorology (2026)