Tag: Landsat
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How to Check Satellite Imagery Quality Before Accepting Delivery
A satellite image can look sharp and still be unsuitable for your project. A cloud may cover the only facility you need to inspect, a missing-data strip may cross your pipeline corridor, or a visually convincing colour image may lack the spectral measurements required for analysis. Satellite imagery quality control should answer two questions: does…
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Can Satellite Imagery Detect Soil Salinity?
Satellite imagery can reveal exposed salt crusts, identify crop patterns consistent with salt stress, and support soil salinity estimates calibrated against ground measurements. These are three different results. A bright patch of soil or a low vegetation index alone cannot establish how saline the soil is, particularly below the surface. For agricultural monitoring, the useful…
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Can Satellite Imagery Measure Shallow-Water Depth?
Yes, satellite imagery can estimate shallow-water depth where enough light reaches the bottom and returns to the sensor. This approach, known as satellite-derived bathymetry (SDB), can help map coastal shallows, identify possible shoals and prioritize areas for detailed surveys. Its usefulness depends on water clarity, bottom conditions, image quality and validation against reliable depth measurements.…
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How to Measure Shoreline Change Without Mistaking Tides for Erosion
A shoreline can move landward between two satellite images even when the beach has lost no sediment. A higher tide, stronger wave run-up or a different position within the seasonal beach cycle can all change where water meets land. Measuring coastal change therefore requires more than extracting a clean boundary. The measurement must follow a…
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Why Satellite Surface Temperature Differs from Air Temperature
A satellite temperature map can show a hot industrial district while a nearby weather station reports a much lower temperature. Both observations may be correct. The satellite estimates the temperature of visible surfaces, while the station measures the air around its sensor. These measurements describe different parts of the urban environment and should answer different…
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How Reliable Is Satellite-Derived Water Turbidity?
Satellite-derived turbidity can support reliable monitoring of sediment plumes, seasonal patterns and unusual changes across rivers, lakes and coastal waters. Its reliability, however, depends on whether the imagery, processing method and retrieval algorithm have been validated for the conditions being monitored. A convincing map is not enough: users need to know how closely the estimates…
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How to Check Historical Tree Cover Before Planting
Checking whether trees existed on a plot before planting requires more than searching a forest-loss map. A useful assessment connects each plot boundary to its planting date, examines evidence from the relevant historical period, and records what the available data can—and cannot—establish. Satellite archives can help screen large numbers of plots, but missing loss records…
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How to Monitor Mining Expansion Using Multi-Temporal Satellite Imagery
Multi-temporal satellite imagery can reveal where a mine’s surface footprint is expanding, which facilities are changing, and how surrounding land is being affected. Reliable monitoring, however, requires more than placing two images side by side. The images must be comparable, the changes must be linked to specific mine features, and the findings must be checked…
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Can Optical Satellites Keep Tracking Floods When Clouds Block the View?
In brief: Landsat and Sentinel-2 can capture flood details well, but they are most vulnerable to the very condition that often accompanies major flooding: cloud cover. Rather than trying to generate a visually plausible cloud-free optical image, this study directly reconstructs whether the surface beneath the clouds is water or non-water. The researchers combined Harmonized…
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NASA’s Landsat 9 successfully launched aboard Atlas V from Vandenberg
United Launch Alliance has launched NASA’s most powerful Earth-imaging satellite, Landsat 9, on an Atlas V rocket. Liftoff occurred at 11:12 AM PDT (18:12 UTC) on Monday, September 27, from Space Launch Complex-3 East (SLC-3E) at Vandenberg Space Force Base in California. Atlas V placed the satellite into a near-polar, sun-synchronous orbit at an altitude…