Why in news?

A scintillometer was recently installed at the Tamil Nadu Rice Research Institute's Critical Zone Observatory in Aduthurai. This instrument will help researchers better understand how heat and moisture move between the land surface and the atmosphere, a crucial factor for climate-resilient agriculture in the Cauvery delta.

Background

• A scintillometer is an optical instrument that measures turbulence in the air by analysing rapid fluctuations in the intensity of a transmitted light beam (known as scintillations). These fluctuations are caused by temperature- and humidity-induced variations in the air's refractive index.
• The device consists of a transmitter, which sends a coherent light beam across a fixed distance, and a receiver that records variations in the beam's intensity. By analysing these variations, scientists can calculate sensible heat flux and moisture exchange between the land and the overlying air.

Working principle

• The instrument is typically mounted on towers or across fields. Minute fluctuations in the beam caused by turbulent air are recorded and processed to estimate how much heat and water vapour is moving from the surface to the atmosphere.
• Because scintillometers sample an entire path rather than a single point, they provide more representative measurements of turbulent fluxes over heterogeneous landscapes.

The Critical Zone Observatory at TRRI

• The Aduthurai Critical Zone Observatory was established by the Tamil Nadu Agricultural University with support from the National Centre for Earth Science Studies and became fully operational in 2022.
• It is one of three such observatories in India and the only one dedicated to agricultural research in Tamil Nadu. Instruments at the site measure weather parameters, soil moisture, groundwater levels, and direct air-surface energy exchanges.
• The data generated - including sensible heat flux from the new scintillometer - will improve estimates of evapotranspiration, soil moisture and microclimate. This information supports irrigation scheduling, weather forecasting and climate-resilient farming in the Cauvery delta.

Significance

• By capturing real-time energy exchanges, the scintillometer helps researchers understand how crops respond to heat stress and drought. Such insights are vital for managing water resources and boosting crop productivity under changing climate conditions.
• The long-term datasets produced by the observatory will aid scientific research, inform policymakers and benefit farmers in one of India's most important rice-growing regions.

Sources: Wikipedia - Scintillometer, National Centre for Earth Science Studies