Artist impression of Sentinel-6 in space. Image courtesy of ESA – P. Carril, CC BY-SA 3.0 IGO
This week we’re putting the focus on the current developments in ocean remote sensing – in the widest sense of the word! Firstly, last Thursday, China launched the Haiyang 1D (HY-1D) satellite, from China’s Taiyuan Satellite Launch Centre on the Long March 2C rocket, into a sun-synchronous orbit at an altitude of approximately 780 km. As the satellite’s name translates as ocean in Chinese, it is unsurprising that this is an ocean monitoring satellite.
In space, it will join HY-1C, launched almost two years ago, forming a twin constellation. Similarly to its sister satellite, Haiyang-1D carries two instruments:
- China Ocean Colour & Temperature Scanner (COCTS) it is a medium-resolution optical radiometer with 8 bands in the visible and near-infrared spectrum and 2 thermal bands.
- Coastal Zone Imager (CZI), a multispectral push-broom instrument with four bands in the visible and near-infrared spectrum and has a spatial resolution of 50 m with a swath width of 950 km.
The satellite will collect daily ocean colour, land and vegetation products. It will also measure daytime sea-surface temperature, suspended sediment and global chlorophyll concentrations; and provide data to support coastal resources, ecosystems, meteorology, water resources and transportation.
It was reported that a few days after its launch, HY-1D sent back its first batch of remote sensing data. This data was received by three ground stations of China’s National Satellite Ocean Application Service’s in Hainan Province, Beijing and Heilongjiang Province
Also from China, stretching the ocean theme a little, it was reported last weekend that it’s polar observing satellite ICE-PATHFINDER (also known as BNU-1) had completed its Antarctic mission having collected over one thousand images of the region in the nine months since its launch. It is now changing to collect data from the northern polar region.
ICE-PATHFINDER is equipped with two high-resolution cameras: the first has a spatial resolution of 80 m with a swath width of 745 km, whilst the second optical camera has a spatial resolution of 8 m with a swath width of 25 km.
The satellite is expected to achieve full coverage of the Arctic in seven days, and they have already received the first batch of Arctic data. This has been an important satellite for China as it has reduced their reliance on other nation’s satellite data for the Polar Regions.
Finally, it was also announced this week that ESA’s Sentinel-6 Michael Freilich satellite, also known as the Jason Continuity mission, has completed its testing programme that began almost 7 months earlier, meaning that it is ready for launch later this year.
Based on CryoSat-2 Sentinel-6 will, like all Sentinels, eventually be a multi-satellite constellation focussing on collecting data over the oceans, coastal areas and inland waters. It will carry two main instruments:
- POSEIDON-4 is a pulse pulse-width limited radar altimeter in the KU and C bands which will continue the dataset begun by the TOPEX/POSEIDON mission launched in August 1992, followed by JASON-1, JASON-2 and JASON-3 creating an almost 30-year unbroken ocean dataset.
- AMR-CÂ is a multi-channel radiometer for high-resolution retrieval of water vapour content over global and coastal ocean.
The satellite will go into a low-earth orbit at approximately 1 336 km and will have revisit time of 10 days with an expected mission life of five years. It’s expected to measure changes in sea-surface topography to an accuracy of one centimetre for 90% of the world’s oceans, and will also measure ocean currents and speed, ocean heat storage, together with temperature and humidity of Earth’s atmosphere.
This joint mission between ESA, NASA, EUMETSAT and NOAA is expected to be launched towards the end of 2020. This certainly could be an exciting year for scientists and researchers working with ocean data.
