NASA Earth Observatory images by Joshua Stevens, using VIIRS and MODIS data from LANCE/EOSDIS Rapid Response and the Level 1 and Atmospheres Active Distribution System (LAADS) and Land Atmosphere Near real-time Capability for EOS (LANCE), and Landsat data from the U.S. Geological Survey.

This week we’re looking at the latest developments in both satellite and aircraft remote sensing, including recent news on satellite remote sensing in China, and how aircraft overflights in England have helped create a new dataset.

Satellite Remote Sensing

Five commercial Earth Observation (EO) satellites were launched last week from the Jiuquan Satellite Launch Center aboard a Kinetica-1 solid rocket. Built by the Bejing based company Minospace, the satellites are believed to have a variety of functions:

• Taijing 1C and Taijing 3B are high-resolution optical satellites.
• Taijing 2B is an experimental satellite focused on monitoring vegetative cover and atmospheric elements.
• Taijing 2D is an experimental satellite for space environmental detection operations.
• Taijing 4C is reported to be a plate-shaped phased array synthetic aperture radar satellite operating in the Ku-band. The data from the satellite is expected to be used for applications such as marine vessel monitoring, disaster monitoring, environmental survey, resources mapping, and crop yield estimation.

Also, last week the China National Space Administration (CNSA) confirmed that the hyperspectral EO satellite, Gaofen-5 01A, also known as Hyperspectral Multifunctional Observation Satellite, had become operational. The satellite was launched in December 2022 into a sun-synchronous orbit at around 700 kilometre altitude, and it has now successfully completed all the in-orbit tests.

Alongside the operational announcement, CNAS noted that to date the satellite had acquired nearly 86,000 images sending 245 terabytes of data back to Earth. CNAS also released a number of products produced from these hyperspectral datasets including a global ozone column concentration monitoring map, soil moisture monitoring map, sea ice monitoring map, water quality monitoring map and other hyperspectral data images.

In addition to the hyperspectral instrument, the satellite also reportedly has a visible camera, spectral imager, greenhouse gas detector, atmospheric environment infrared detector at very high spectral resolution, differential absorption spectrometer for atmospheric trace gas, and multi-angle polarisation detector. It’s believed the data will be used for ecological environment dynamic monitoring, natural resource investigation, and atmospheric composition detection, that will improve global air pollutant monitoring capabilities including monitoring of methane anomalous emission sources.

Aircraft Remote Sensing

Researchers at the UK Centre for Ecology & Hydrology (UKCEH) yesterday released the most comprehensive map of hedgerows across England.

Hedgerows have been part of the landscape since the Bronze Age, creating natural fences and boundary markings. They are critical to biodiversity, providing habitats and ecosystems for hundreds of plants and animals, and they also can capture and store large amounts of carbon.

Historically, hedgerow maps have been created by scaling up field surveys. However, the new map was created by using the Environment Agency’s release of LIDAR (Light Detection and Ranging) remote sensing data for the whole of England, collected using five years of aircraft overflights between 2016 and 2021 as part of its mapping work. The dataset is available to download from the Environmental Information Data Centre website. UKCEH carried out on-site field validation surveys, comparing areas of one square kilometre with the dataset and found there was a 96% accuracy.

The map shows that there are 390,000 km of hedgerows in England, determined as hedges between 1 and 6 metres tall – this height assessment is a critical indicator of hedgerow quality.

While half of the country’s hedgerows were lost in the second half of the twentieth century due to urban development and more intensive farming, in recent years there has been a lack of maintenance resulting in gaps in hedges or overgrown lines of trees. Information to support this was also identified with 185,000 km of hedgerows noted above 6m tall which are likely to be mature overgrown hedges together with an additional 67,000 km of lines of vegetation below 1 metre which could be either degraded, cut or newly-planted hedges.

It is hoped this map will guide planting and habitat restoration of these critical natural resources.

Conclusion

There are lots of different types of remote sensing and, even with all the recent satellite launches, the data released this week shows that there are still applications where a closer view of the planet is helpful.