Latest news with #Sentinel-1
India Today
6 days ago
- Climate
- India Today
Maps: Satellite data reveals extent of Assam floods
The flood situation in Assam's Brahmaputra valley remained severe on Monday, with water levels continuing to rise across several regions, according to officials. Satellite imagery and flood-mapping data analysed by India Today's OSINT team using Sentinel-1 SAR (Synthetic Aperture Radar) data revealed that large areas of land were submerged under the same methodology, the composite overview imagery showed extensive inundation across key districts in Assam, including Nalbari, Guwahati, Nagaon, Silchar, Golaghat and Kamrup. Isolated flood signatures were also detected across nearly 19-20 districts, including Dhemaji, Dibrugarh, Darrang, Biswanath, Tinsukia, Karbi Anglong, Karbi Anglong West, Kamrup, Hojai, Sonitpur, Charaideo, Sivasagar, Majuli and In Assam's Kamrup Metropolitan district, flooding was primarily observed along the floodplains of the Digaru river. Satellite imagery indicated severe inundation in key urban zones, particularly in the Garchuk and Boragaon localities of Guwahati. Blue shades represent flooding in Kamrup. A similar pattern emerged in the satellite imagery of Nagaon district, where floodwaters were concentrated along the floodplains of the Kapili river. Significant inundation was detected near Kaziranga National Park, as well as in the areas of Barhampur, Barafuti and Kampur Google Earth Engine (GEE), we processed Sentinel-1 SAR datasets to perform time-series analysis of flood dynamics. By comparing radar data from the pre-monsoon and monsoon periods, we identified changes in surface water coverage that allowed us to detect newly-flooded zones. The use of SAR data, which can penetrate cloud cover and heavy rain, allowed consistent monitoring even during peak weather conditions. This approach enabled clear visualization of flood extent across Assam's impacted this analysis, we utilised pre-flooding (April 16 to May 7) and intra-flooding (May 31 to June 1) remote sensing datasets to conduct a differential assessment of surface water extent. By analysing temporal variations in satellite imagery, we were able to highlight flood-affected zones with enhanced spatial India Meteorological Department (IMD) has issued a red alert for Assam and Meghalaya, warning the states of heavy to very heavy rainfall in the coming week. Similar alerts have been issued for Nagaland, Mizoram, Manipur and Tripura, which are also expected to receive intense Watch IN THIS STORY#Assam
NDTV
25-05-2025
- Science
- NDTV
Picture From Space Captures Multicoloured Lake Alakol In Kazakhstan
Hidden in the remote eastern reaches of Kazakhstan, Lake Alakol is a natural wonder that blends striking beauty with ancient healing lore. Revered for its shimmering hues – ranging from deep indigo to rust red and turquoise – the lake has long drawn attention not just for its surreal appearance but also for its soothing properties, believed to ease ailments like eczema, joint pain and dry skin. Now, thanks to high-resolution images captured by the European Space Agency's Sentinel-1 satellite, the world is beginning to witness the lake's mesmerising, ever-shifting palette from space – unveiling a spectacle that changes with the seasons. Lake Alakol holds a special place in Central Asia's geography. While the lake spans around 1,000 square miles, its most distinctive feature is its isolation from the sea. Fed by the Urzhar and Emil rivers, the lake is completely cut off from any ocean, creating an enclosed system. Anything that flows in stays there until the sun evaporates it, leaving minerals and salts behind. This continuous cycle has increased the salinity of the water, which is now high enough to repel freshwater fish, yet mild enough for daring swimmers. The lake typically freezes over for two months at the end of winter before breaking apart in early spring, leaving floating fragments that gleam like shattered glass. The size of its surface varies from year to year. The shoreline may extend several hundred yards in response to a rainy spring, but it retracts after three consecutive dry summers. These fluctuations affect the salt content and the algae that give the water its turquoise or rust-red colour. The term "the water's mood" is often used to describe this chameleon-like quality. European Space Agency scientists can now observe these colour shifts from above using Sentinel-1 radar. In addition to being aesthetically pleasing, Lake Alakol is an important biological habitat, home to several rare bird species. In recognition of its ecological significance, the lake was included in UNESCO's Man and the Biosphere Program in 2013. It was also added to the global list of protected wetlands by Ramsar, an international convention for the conservation of wetlands.
Yahoo
28-04-2025
- Science
- Yahoo
Satellite images reveal how Earth's surface moved during deadly Myanmar earthquake
When you buy through links on our articles, Future and its syndication partners may earn a commission. Earth-observing satellites reveal significant ground shift in central Myanmar following the devastating earthquakes that ravaged the area in March. The European Space Agency's (ESA) Copernicus Sentinel-1A satellite captured radar images of the country just one day before a powerful magnitude 7.7 earthquake struck on March 28. The Sentinel-1C satellite revisited the site a few days later, capturing the aftermath of the seismic event. "Using satellite radar images, scientists can map the extent of ruptures and identify areas of increased seismic risk," ESA officials said in a statement. ESA's Sentinel-1 mission includes two satellites positioned 180 degrees apart in orbit above Earth, enabling them to collectively scan the entire globe every six days. Sentinel-1's advanced radar imaging capabilities, including Terrain Observation with Progressive Scans and burst overlap interferometry, allow for precise measurement of ground motion in both east-west and north-south directions. By comparing the satellite data collected before and after the Myanmar earthquake (a method called synthetic aperture radar interferometry), scientists were able to create a detailed map illustrating ground movement, also known as an interferogram, along the Sagaing Fault — one of the most active strike-slip faults in Southeast Asia, running north to south through the center of Myanmar. RELATED STORIES: — Turkey earthquake opened 190-mile-long fissure, satellite images show — Satellites reveal how deadly Morocco earthquake moved ground (photos) — Earthquakes seem more intense after cosmic ray strikes. Scientists say this is why. The earthquake rupture, which is the sudden break and movement along a fault, extended approximately 342 miles (550 kilometers) along the Sagaing Fault — one of the longest documented surface ruptures ever recorded for a strike-slip fault. The interferogram revealed 63 inches (160 centimeters) of ground displacement along the fault line, indicating significant movement on either side of the fault. This data provides critical insight on the earthquake, which can aid in disaster response efforts. "These data are a game-changer," Dirk Geudtner, ESA's Sentinel-1 System Manager, said in the statement. "They enable faster, more accurate assessments after disasters, and help us to improve earthquake models globally."
