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Time of India
22-05-2025
- Science
- Time of India
NASA scientists reveal how trees can predict volcanic eruptions from space
Recent breakthroughs in satellite and environmental sensing technology have introduced a promising method for detecting volcanic unrest by monitoring changes in vegetation health from space. Tired of too many ads? go ad free now This innovative approach, supported by in-field data from the Smithsonian Tropical Research Institute's AVUELO (Airborne Validation Unified Experiment: Land to Ocean) mission, enhances early warning systems for volcanic eruptions . By analysing how trees respond to volcanic CO₂ emissions, scientists can detect subtle signs of increased volcanic activity, potentially providing earlier alerts and improving the accuracy of volcanic forecasts, especially in remote or hard-to-reach areas. NASA satellite images can spot volcanic activity through plant growth As magma rises beneath the Earth's surface, it releases gases, such as carbon dioxide (CO₂). Although existing volcanic monitoring systems generally depend on seismic activity, ground deformation, and on-site gas measurements, detecting low-level CO₂ release from space is still a huge challenge due to atmospheric dilution and sensor limitations. Source: NASA Nonetheless, scientists have found a key biological proxy: trees. Plant life, especially trees that grow near active volcanoes, may take up volcanic CO₂ through roots. This absorption can lead to visibly greener and healthier leaves as a result of the fertilization effect of more CO₂. These physiological effects can be measured using satellite imagery, providing an indirect but quantifiable measure of subsurface volcanic activity. NASA tracks volcanic activity through vegetation changes The AVUELO project, coupled with NASA's Landsat 8 satellite and airborne sensors, has shown the potential for spectral analysis to track these plant changes across vast and sometimes inaccessible volcanic areas. Tired of too many ads? go ad free now By mapping changes in vegetation indices—like the Normalized Difference Vegetation Index (NDVI)—researchers can detect regions where tree health has anomalously increased, which could be related to concurrent volcanic gas emissions. Source: NASA A dramatic demonstration of the phenomenon occurred alongside Costa Rica's Rincón de la Vieja volcano. Volcanic CO₂ there warmed and bubbled through water pools while altering vegetation on the ground at the same time. Those observations on the ground as well as in orbit validate the idea that the health of trees could be an early warning sign of magmatic activity. NASA aims to enhance volcano early warning systems As Dr. Florian Schwandner, the Director of the Earth Science Division at NASA's Ames Research Center, explains, the intention is not to supplant current volcanic monitoring methods but to improve and add to their effectiveness. "Volcano early warning systems exist," Schwandner said, "The aim here is to make them better and make them earlier." Conventional approaches are hampered by such volcanoes in remote or heavily forested areas with poor access for placing ground sensors. By utilizing tree response as a proxy for volcanic CO₂, this barrier can be overcome. As McGill University's Dr. Robert Bogue describes, "Volcanoes release a lot of carbon dioxide, but the modest quantities emitted before an eruption go undetectable from space. The concept is to look for something measurable instead—trees provide us with that signal. How ground observations enhance satellite volcano monitoring To verify satellite data, scientists integrate space data with ground observations. Field staff take leaf samples and obtain measurements of CO₂ near volcanoes to verify the accuracy of the vegetation changes determined by satellites. This synthesis approach guarantees the biological proxy's reliability and improves predictability. According to NASA reports, Dr. Nicole Guinn, a volcanologist at the University of Houston, highlighted the value of synthesizing a wide variety of satellite assets, ranging from NASA's Terra to ESA's Sentinel-2, in creating a complete image of the evolution of vegetation on volcanic terrain like Mount Etna in Italy. But she noted that "satellite data alone is not enough," highlighting the need for field verification to establish coherence between vegetation signals and volcanic gas emissions. This new approach marks a major breakthrough in remote sensing and environmental monitoring. Through the natural biological reactions of trees in response to volcanic gas release, researchers are creating an additional tool that might give earlier indications of volcanic eruptions—perhaps days or weeks ahead of conventional indicators. Since climate-resilient monitoring grows more and more vital in the wake of increased global population areas around the vicinity of volcanic regions, this tree-based signal detection presents a scalable and non-invasive approach for the improvement of global volcanic early warning systems. Also Read |
Time of India
27-04-2025
- Business
- Time of India
Maharashtra govt to start using satellite images to assess crop damage and compensation
The Maharashtra government will now use satellite imagery and NDVI to assess crop damage, excluding droughts, for faster and more accurate aid distribution to farmers. This technology-driven approach aims to replace traditional on-field surveys and curb inflated damage claims. The initiative, delayed due to opposition, is set to roll out across the state after a successful study group report. Tired of too many ads? Remove Ads Tired of too many ads? Remove Ads Tired of too many ads? Remove Ads The Maharashtra government has decided to use satellite imagery and Normalised Difference Vegetation Index ( NDVI ) standards, instead of traditional on-field surveys, to assess crop damage and provide assistance to farmers, a senior official said. The technology-driven assessment will, however, not cover measures how healthy or stressed vegetation is by analysing plants' reflection or absorption of specific wavelengths of sensors measure this reflected light, enabling accurate analysis of crops' condition, a senior agriculture department official explained to PTI."Except for droughts, from now onwards, aid for crop damage due to natural disasters will be provided based on satellite images and NDVI parameters, instead of traditional on-field surveys."This technology will also be utilised for crop insurance purposes, enabling accurate assessments of crop losses and damage to vegetation due to natural calamities," the official said on a study group had recommended implementing this system on a pilot basis in one district. However, the government has decided to roll it out across the entire state in one official said the opposition by some ministers delayed the scheduled January 1, 2025, rollout of the new system."Finally, after a delay of three months, the decision has been taken, and assistance to farmers will now be technology-based," he NDVI is a numerical indicator, ranging from -1 to +1, that assesses the presence and health of green close to 1 indicate high vegetation density and health, while values closer to 0 or negative represent non-vegetated surfaces like bare soil, water, or Madhya Pradesh uses the NDVI method to assess agricultural damages, and a study group formed to examine their procedures has already submitted its to the official, the study group recommended that during the Kharif 2025-26 season, NDVI and other indices such as Normalised Difference Water Index (NDWI), Vegetation Condition Index (VCI), Enhanced Vegetation Index (EVI), and Soil Adjusted Vegetation Index (SAVI) be applied in selected districts across Marathwada, Vidarbha, Western Maharashtra, and north a meeting chaired by the Additional Chief Secretary of the Revenue Department in December 2024, approval was granted for using satellite imagery to evaluate crop damage through NDVI the Vasantrao Naik Marathwada Agricultural University in Parbhani and the All-India Coordinated Research Project on Agrometeorology were commissioned to assist with the project. An expenditure of Rs 1 crore has been sanctioned for this initiative."Under this project, satellite images will be captured every seven days to monitor the conditions of cultivated areas across Maharashtra," the senior official explained.A retired agriculture officer said on condition of anonymity that some MLAs or local representatives pressure government officials to inflate crop damage figures so that a higher compensation amount can be claimed."This leads to the government spending a higher amount on crop damage. The NDVI data is expected to be used to put a check on such practice," he February 24, 2024, the government adopted NDVI as an additional standard for determining crop losses caused by natural disasters, excluding discussions had been ongoing since 2022, it was after the formation of the Shinde government and subsequent repeated rain-related damages that a committee was formed to finalise the committee recommended that assistance be based primarily on NDVI per the guidelines, a preliminary alert is triggered if rainfall exceeds 50 per cent of the average over five consecutive days, with a minimum of 10 mm each day. Subsequently, if the NDVI reading in the affected area falls to 0.5 or below between July 15 and October 15, a secondary alert is raised, confirming significant crop damage."NDVI measures how healthy or stressed vegetation is by analysing how plants reflect or absorb specific wavelengths of light. Satellite sensors measure this reflected light, making it possible to assess crops' condition accurately," the official said.
Time of India
22-04-2025
- Health
- Time of India
Construction, decimation of green cover turning Kol into urban heat island: Study
1 2 3 Kolkata: The soaring summer heat is linked to shrinking green cover and rising built-up areas, according to a report by the Centre for Science and Environment (CSE). Summers in Kolkata are becoming increasingly unbearable, not just because of rising mercury but due to the city's rapidly transforming landscape. The report highlights that unchecked urban expansion, shrinking green space and diminishing water bodies are altering the city's natural ability to stay cool, turning it into a heat trap. CSE, a Delhi-based environmental think tank, conducted a study from 2001 to 2023, analysing land surface temperatures and humidity trends across six megacities — Delhi, Mumbai, Kolkata, Hyderabad, Bengaluru, Chennai — and four smaller cities — Chandigarh, Jaipur, Lucknow and Pune. The findings reveal a disturbing trend: urban areas are becoming heat zones, with heatwaves growing more intense. In Kolkata, the study found that the built-up area, which includes concrete infrastructure and roads, rose sharply from 70% in 2001 to 80.1% in 2023. In contrast, green cover, crucial for temperature regulation, slightly declined from 15.2% to 14.5%. Alarmingly, scrubland and barren land, which earlier acted as buffer zones, plummeted from 9.8% to 3.4%, and water bodies reduced by more than half — from 5.1% to 1.9%. These changes are key contributors to the Urban Heat Island (UHI) effect, where densely built-up urban areas retain more heat than their surroundings. With less vegetation and water to moderate temperatures, heat lingers well into the night, increasing public health risks, particularly during summer and monsoon months. What makes Kolkata's heat even more punishing is its high humidity. The CSE report underscores that humidity has become a major driver of urban heat stress, particularly in coastal cities like Kolkata and Mumbai. The Heat Index — a measure of how hot it feels when relative humidity is factored in — has skyrocketed. In cities like Chennai, humidity added nearly 7°C to the perceived temperature. Kolkata, with its already high humidity levels, now frequently crosses thresholds that cause extreme heat stress. CSE's analysis utilised satellite data from Landsat 7 and 8, focusing on the Normalised Difference Vegetation Index (NDVI) to assess green cover during India's hottest months — April to June. NDVI readings showed a consistent decline in vegetation, particularly during heatwave periods, correlating directly with the city's rising thermal stress. The reduced green cover means the city has lost its natural heat-mitigation shield, accelerating the impact of climate change at a hyperlocal level. The CSE report makes it clear: India's cities are becoming hotter, wetter, and more dangerous, particularly for vulnerable populations. Without a clear and immediate shift in urban planning — focused on restoring green cover, conserving water bodies, and limiting unplanned construction — the situation is set to worsen.
