Algae Starting To Bloom

Algal Blooms in Lake Erie, around Monroe, acquired by Sentinel-2 on 3rd August 2017. Data Courtesy of ESA/Copernicus.

Algae have been making the headlines in the last few weeks, which is definitely a rarely used phrase!

Firstly, the Lake Erie freshwater algal bloom has begun in the western end of the lake near Toledo. This is something that is becoming an almost annual event and last year it interrupted the water supply for a few days for around 400,000 residents in the local area.

An algae bloom refers to a high concentration of micro algae, known as phytoplankton, in a body of water. Blooms can grow quickly in nutrient rich waters and potentially have toxic effects. Although a lot of algae is harmless, the toxic varieties can cause rashes, nausea or skin irritation if you were to swim in it, it can also contaminate drinking water and can enter the food chain through shellfish as they filter large quantities of water.

Lake Erie is fourth largest of the great lakes on the US/Canadian border by surface area, measuring around 25,700 square km, although it’s also the shallowest and at 484 cubic km has the smallest water volume. Due to its southern position it is the warmest of the great lakes, something which may be factor in creation of nutrient rich waters. The National Oceanic and Atmospheric Administration produce both an annual forecast and a twice weekly Harmful Algal Bloom Bulletin during the bloom season which lasts until late September. The forecast reflects the expected biomass of the bloom, but not its toxicity, and this year’s forecast was 7.5 on a scale to 10, the largest recent blooms in 2011 and 2015 both hit the top of the scale. Interestingly, this year NOAA will start incorporating Sentinel-3 data into the programme.

Western end of Lake Erie acquired by Sentinel-2 on 3rd August 2017. Data

Despite the phytoplankton within algae blooms being only 1,000th of a millimetre in size, the large numbers enable them to be seen from space. The image to the left is a Sentinel-2 image, acquired on the 3rd August, of the western side of the lake where you can see the green swirls of the algal bloom, although there are also interesting aircraft contrails visible in the image. The image at the start of the top of the blog is zoomed in to the city of Monroe and the Detroit River flow into the lake and the algal bloom is more prominent.

Landsat 8 acquired this image of the northwest coast of Norway on the 23rd July 2017,. Image courtesy of NASA/NASA Earth Observatory.

It’s not just Lake Erie where algal blooms have been spotted recently:

  • The Chautauqua Lake and Findley Lake, which are both just south of Lake Erie, have reported algal blooms this month.
  • NASA’s Landsat 8 satellite captured the image on the right, a bloom off the northwest coast of Norway on the 23rd July. It is noted that blooms at this latitude are in part due to the sunlight of long summer days.
  • The MODIS instrument onboard NASA’s Aqua satellite acquired the stunning image below of the Caspian Sea on the 3rd August.

Image of the Caspian Sea, acquired on 3rd August 2017, by MODIS on NASA’s Aqua satellite. Image Courtesy of NASA/NASA Earth Observatory.

Finally as reported by the BBC, an article in Nature this week proposes that it was a takeover by ocean algae 650 million years ago which essentially kick started life on Earth as we know it.

So remember, they may be small, but algae can pack a punch!

Silver Anniversary for Ocean Altimetry Space Mission

Artist rendering of Jason-3 satellite over the Amazon.
Image Courtesy NASA/JPL-Caltech.

August 10th 1992 marked the launch of the TOPEX/Poseidon satellite, the first major oceanographic focussed mission. Twenty five years, and three successor satellites, later the dataset begun by TOPEX/Poseidon is going strong providing sea surface height measurements.

TOPEX/Poseidon was a joint mission between NASA and France’s CNES space agency, with the aim of mapping ocean surface topography to improve our understanding of ocean currents and global climate forecasting. It measured ninety five percent of the world’s ice free oceans within each ten day revisit cycle. The satellite carried two instruments: a single-frequency Ku-band solid-state altimeter and a dual-frequency C- and Ku-band altimeter sending out pulses at 13.6 GHz and 5.3 GHz respectively. The two bands were selected due to atmospheric sensitivity, as the difference between them provides estimates of the ionospheric delay caused by the charged particles in the upper atmosphere that can delay the returned signal. The altimeter sends radio pulses towards the earth and measures the characteristics of the returned echo.

When TOPEX/Poseidon altimetry data is combined with other information from the satellite, it was able to calculate sea surface heights to an accuracy of 4.2 cm. In addition, the strength and shape of the return signal also allow the determination of wave height and wind speed. Despite TOPEX/Poseidon being planned as a three year mission, it was actually active for thirteen years, until January 2006.

The value in the sea level height measurements resulted in a succeeding mission, Jason-1, launched on December 7th 2001. It was put into a co-ordinated orbit with TOPEX/Poseidon and they both took measurements for three years, which allowed both increased data frequency and the opportunity for cross calibration of the instruments. Jason-1 carried a CNES Poseidon-2 Altimeter using the same C- and Ku-bands, and following the same methodology it had the ability to measure sea-surface height to an improved accuracy of 3.3 cm. It made observations for 12 years, and was also overlapped by its successor Jason-2.

Jason-2 was launched on the 20 June 2008. This satellite carried a CNES Poseidon-3 Altimeter with C- and Ku-bands with the intention of measuring sea height to within 2.5cm. With Jason-2, National Oceanic and Atmospheric Administration (NOAA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) took over the management of the data. The satellite is still active, however due to suspected radiation damage its orbit was lowered by 27 km, enabling it to produce an improved, high-resolution estimate of Earth’s average sea surface height, which in turn will help improve the quality of maps of the ocean floor.

Following the established pattern, Jason-3 was launched on the 17th January 2016. It’s carrying a Poseidon-3B radar altimeter, again using the same C and Ku bands and on a ten day revisit cycle.

Together these missions have provided a 25 year dataset on sea surface height, which has been used for applications such as:

  • El Niño and La Niña forecasting
  • Extreme weather forecasting for hurricanes, floods and droughts
  • Ocean circulation modelling for seasons and how this affects climate through by moving heat around the globe
  • Tidal forecasting and showing how this energy plays an important role in mixing water within the oceans
  • Measurement of inland water levels – at Pixalytics we have a product that we have used to measure river levels in the Congo and is part of the work we are doing on our International Partnership Programme work in Uganda.

In the future, the dataset will be taken forward by the Jason Continuity of Service (Jason-CS) on the Sentinel-6 ocean mission which is expected to be launched in 2020.

Overall, altimetry data from this series of missions is a fantastic resource for operational oceanography and inland water applications, and we look forward to its next twenty five years!

Blue Holes from Space

Andros Island in The Bahamas. Acquired by Landsat 8 in February 2017. Data courtesy of NASA.

Blue holes are deep marine caverns or sinkholes which are open at the surface, and they get their name from their apparent blue colour of their surface due to the scattering of the light within water. The often contain both seawater and freshwater, and in their depths the water is very clear which makes them very popular with divers.

The term ‘blue hole’ first appeared on sea charts from the Bahamas in 1843, although the concept of submarine caves had been described a century earlier (from Schwabe and Carew, 2006). There are a number of well-known blue holes in Belize, Egypt and Malta amongst others. The Dragon Hole in the South China Sea is believed to be the deepest blue hole with a depth of 300 metres.

The Andros Island in The Bahamas has the highest concentration of blue holes in the world, and last week we watched a television programme called River Monsters featuring this area. The presenter, Jeremy Wade, was investigating the mythical Lusca, a Caribbean sea creature which reportedly attacks swimmers and divers pulling them down to their lairs deep within of the blue holes. Jeremy fished and dived some blue holes, and spoke to people who had seen the creature. By the end he believed the myth of the Lusca was mostly likely based on a giant octopus. Whilst this was interesting, by the end of the programme we were far more interested in whether you could see blue holes from space.

The image at the top is Andros Island. Although, technically it’s an archipelago, it is considered as a single island. It’s the largest island of The Bahamas and at 2,300 square miles is the fifth largest in the Caribbean. There are a number of well known blue holes in Andros, both inland and off the coast, such as:

Blues in the Blue Hole National Park on the Andros Island in The Bahamas. Acquired by Landsat 8 in February 2017. Data courtesy of NASA.

  • Blue Holes National Park covers over 33,000 acres and includes a variety of blue holes, freshwater reservoirs and forests within its boundaries. The image to the right covers an area of the national park. In the centre, just above the green water there are five black circles  – despite the colour, these are blue holes.
  • Uncle Charlie’s Blue Hole, also called Little Frenchman Blue Hole, is just off Queen’s Highway in Nicholls Town and has a maximum depth of 127 metres.
  • Atlantis Blue Hole has a maximum depth of about 85 metres.
  • Stargate Blue Hole his blue hole is located about 500 miles inland from the east coast of South Andros on the west side of The Bluff village.
  • Guardian Blue Hole is in the ocean and is believed to have the second deepest cave in The Bahamas, with a maximum explored depth of 133 metres.

Blue hole in the south of Andros Island in The Bahamas. Acquired by Landsat 8 in February 2017. Data courtesy of NASA.

The image to the right is from the south of the island. Just off the centre, you can see a blue hole surrounded by forests and vegetation.

So we can confirm that the amazing natural features called blue holes can be seen from space, even if they don’t always appear blue!

World Oceans Day

Phytoplankton Bloom off South West England. Acquired by MODIS on 12th June 2003. Data courtesy of NASA.

June 8th is World Oceans Day. This is an annual global celebration of the oceans, their importance and how they can be protected for the future.

The idea of a World Ocean Day was originally proposed by the Canadian Government at the Earth Summit in Rio in 1992. In December 2008 a resolution was passed by United Nations General Assembly which officially declared that June 8th would be World Oceans Day. The annual celebration is co-ordinated by the Ocean Project organisation, and is growing from strength to strength with over 100 countries having participated last year.

There is a different theme each year and for 2017 it’s “Our Oceans, Our Future”, with a focus on preventing plastic pollution of the ocean and cleaning marine litter.

Why The Oceans Are Important?

  • The oceans cover over 71% of the planet and account for 96% of the water on Earth.
  • Half of all the oxygen in the atmosphere is released by phytoplankton through photosynthesis. Phytoplankton blooms are of huge interest to us at Pixalytics as despite their miniscule size, in large enough quantities, phytoplankton can be seen from space.
  • They help regulate climate by absorbing around 25% of the CO2 human activities release into the atmosphere.
  • Between 50% and 80% of all life on the planet is found in the oceans.
  • Less than 10% of the oceans have been explored by humans. More people have stood on the moon than the deepest point of the oceans – the Mariana Trench in the Pacific Ocean at around 11 km deep.
  • Fish accounted for about 17% of the global population’s intake of animal protein in 2013.

Why This Year’s Theme Is Important?

The pollution of the oceans by plastic is something which affects us all. From bags and containers washed up on beaches to the plastic filled garbage gyres that circulate within the Atlantic, Pacific and Indian Oceans, human activity is polluting the oceans with plastic and waste. The United Nations believe that as many as 51 trillion particles of microplastic are in the oceans, which is a huge environmental problem.

Everyone will have seen images of dolphins, turtles or birds either eating or being trapped by plastic waste. However, recently Dr Richard Kirby – a friend of Pixalytics – was able to film plastic microfibre being eaten by plankton. As plankton are, in turn, eaten by many marine creatures, this is one example of how waste plastic is entering the food chain. The video can seen here on a BBC report.

Dr Kirby also runs the Secchi Disk project which is a citizen science project to study phytoplankton across the globe and receives data from every ocean.

Get Involved With World Oceans Day

The world oceans are critical to the health of the planet and us! They help regulate climate, generate most of the oxygen we breathe and provide a variety of food and sources of medicines. So everyone should want to help protect and conserve these natural environments. They are a number of ways you can get involved:

  • Participate: There are events planned all across the world. You can have a look here and see if any are close to you.
  • Look: The Ocean Project website has a fantastic set of resources available.
  • Think: Can you reduce your use, or reliance on plastic?
  • Promote: Talk about World Oceans Day, Oceans and their importance.

Small Sea Salinity & Satellite Navigation Irrigation

Artists impression of the Soil Moisture and Ocean Salinity (SMOS) satellite. Image courtesy of ESA – P. Carril.

A couple of interesting articles came out in the last week relating to ESA’s Soil Moisture and Ocean Salinity (SMOS) mission. It caught our attention, as we’re currently knee deep in SMOS data at the moment, due to the soil moisture work we’re undertaking.

SMOS was launched in November 2009 and uses the interferometry technique to make worldwide observations of soil moisture over land and salinity over the ocean. Although its data has also been used to measure floating ice and calculate crop-yield forecasts.

The satellite carries the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) instrument, which is a 2D interferometric L-band radiometer with 69 antenna receivers distributed on a Y-shaped deployable antenna array. It has a temporal resolution of three days, with a spatial resolution of around 50 km.

A recent ESA article once again showed the versatility of SMOS, reporting that it was being used to measure the salinity in smaller seas, such as the Mediterranean. This was never an anticipated outcome due to radio interference and the land-sea boundary contamination – where the land and ocean data can’t be distinguished sufficiently to provide high quality measurements.

However, the interference has been reduced by shutting down illegal transmitters interrupting the SMOS signal and the land-sea contamination has been reduced by work at the Barcelona Expert Centre to change the data processing methodology.

All of this has meant that it’s possible to use SMOS to look at how water flows in and out of these smaller seas, and impact on the open oceans. This will help complement the understanding being gained from SMOS on ocean climate change, ocean acidification and the El Niño effect.

A fascinating second article described a new methodology for measuring soil moisture using reflected satellite navigation signals. The idea was originally from ESA engineer Manuel Martin-Neira, who worked on SMOS – which we accept is a bit more of a tenuous link, but we think it works for the blog! Manuel proposed using satellite navigation microwave signals to measure terrestrial features such as the topography of oceans.

This idea was further developed by former ESA employee Javier Marti, and his company Divirod, and they have created a product to try and reduce the overuse of irrigation. According to Javier, the system compares reflected and direct satnav signals to reveal the moisture content of soil and crops and could save around 30% of water and energy costs, and improve crop yields by 10-12%. It is a different methodology to SMOS, but the outcome is the same. The work is currently been tested with farmers around the Ogallala aquifer in America.

For anyone working in soil moisture, this is an interesting idea and shows what a fast moving field remote sensing is with new approaches and products being developed all the time.

Islands of Sand

Animation showing the creation of islands in Dubai between 2001 & 2009 using Landsat images. Data courtesy of NASA.

This week we’re focusing on the development of Dubai’s land-coast interface between July 2001 and October 2009, looking specifically at the creation of the Palm islands and the World Archipelago. Dubai is the most populous city in the United Arab Emirates, home to 2.7 million people as of January 2017. In a place where Dubai police vehicles include a Lamborghini and a Ferrari, and where it’s possible to buy gold bars from vending machines perhaps it’s not surprising to see the creation of extravagant islands.

Palm Islands & The World Archipelago

In the animation at the top of the blog, the development of the Palm Islands and The World Archipelago are clearly visible. The first island created was Palm Jumeirah, the smallest of the three planned palm islands, and can be seen just off centre on the animation. It consists of a tree trunk, a crown with seventeen fronds and a surrounding crescent, and is approximately 25 square kilometres in size. Construction began in 2001 and was completed in 2006. The workers used GPS signals to determine the correct place to deposit sand to create the palm effect.

Built in tandem were the Palm Jebel Ali and The World Archipelago. Construction began in 2002 and was expected to be completed in 2015, however work stopped in 2008 due to the financial crisis. Work has remained suspended on Palm Jebel Ali, but development on the World may be about to start. The World has three hundred islands reclaimed from the sea, but most of them are bare sand. In the last twelve months there have been rumours that ‘The Heart of Europe’ project and floating seahorses around St Petersburg island could be developed in the near future.

It is also possible to see the preliminary creation of Palm Deira at the top of the animation. 300 million cubic metres of sand were used to form the initial reclamation. However, between 2009 and 2016 there has been no further development.

Images of Dubai in 2001, left, and 2009 taken by Landsat 7. Data courtesy of NASA.

It is also worth noting the significant urban sprawl between the first and last images. Dubai’s population increased by 95%, from 910,336 to 1,770,978, during the period we’re looking at and whilst the growth of Dubai is obvious, it is particularly visible southeast of the Palm Jumeirah development.

Creating the Time Series Animation

The animation was created using the first (blue) visible band of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument. In May 2003, the scan line corrector – used to compensate for forward motion of the spacecraft, ensuring scan lines are parallel – failed. Consequently, the instrument images in a zigzag fashion; some data is captured twice, whilst some is not captured at all. As a result, 22 % of data in Landsat 7 images post May 2003 are missing. To compensate for this we’ve used a Geospatial Data Abstraction Library (GDAL) tool to fill “no data” regions by interpolating from nearby valid pixels. The results, whilst not perfect, are nearly indistinguishable at this resolution.

Impacts of the Islands

The development of these islands has not been without its criticism as it has impacted the local ecology. The dredging of sand has increased the turbidity of the seawater, with sediment transport evident in the animation, which has damaged coral reefs. In addition, water around parts of the islands can remain almost stationary for weeks, increasing the risk of algal blooms. Whilst fish have returned to these waters, they are not the same species as were there before.

Viewed from space, both the speed and scale of the development is mesmerising. It is no surprise that tourism is a vitally important part of the local economy, attracting more than 13 million visitors in 2014. With the limitations of available land in Dubai, developments are sure to start again.

 

Blog produced by Tom Jones on work placement with Pixalytics Ltd.

Earth Observation Looking Good in 2017!

Artist's rendition of a satellite - paulfleet/123RF Stock Photo

Artist’s rendition of a satellite – paulfleet/123RF Stock Photo

2017 is looking like an exciting one for Earth Observation (EO), judging by the number of significant satellites planned for launch this year.

We thought it would be interesting to give an overview of some of the key EO launches we’ve got to look forward to in the next twelve months.

The European Space Agency (ESA) has planned launches of:

  • Sentinel-2B in March, Sentinel-5p in June and Sentinel-3B in August – all of which we discussed last week.
  • ADM-Aeolus satellite is intended to be launched by the end of the year carrying an Atmospheric Laser Doppler Instrument. This is essentially a lidar instrument which will provide global measurements of wind profiles from ground up to the stratosphere with 0.5 to 2 km vertical resolution.

From the US, both NASA and NOAA have important satellite launches:

  • NASA’s Ionospheric Connection Explorer (ICON) Mission is planned for June, and will provide observations of Earth’s ionosphere and thermosphere; exploring the boundary between Earth and space.
  • NASA’s ICESat-2 in November that will measure ice sheet elevation, ice sheet thickness changes and the Earth’s vegetation biomass.
  • In June NOAA will be launching the first of its Joint Polar Satellite System (JPSS) missions, a series of next-generation polar-orbiting weather observatories.
  • Gravity Recovery And Climate Experiment – Follow-On (GRACE_FO) are a pair of twin satellites to extend measurements from the GRACE satellite, maintaining data continuity. These satellites use microwaves to measure the changes in the Earth’s gravity fields to help map changes in the oceans, ice sheets and land masses. It is planned for launch right at the end of 2017, and is a partnership between NASA and the German Research Centre for Geosciences.

Some of the other launches planned include:

  • Kanopus-V-IK is a small Russian remote sensing satellite with an infrared capability to be used for forest fire detection. It has a 5 m by 5 m spatial resolution over a 2000 km swath, and is planned to be launched next month.
  • Vegetation and Environment monitoring on a New MicroSatellite (VENµS), which is partnership between France and Israel has a planned launch of August. As its name suggests it will be monitoring ecosytems, global carbon cycles, land use and land change.
  • KhalifaSat is the third EO satellite of United Arab Emirates Institution for Advanced Science and Technology (EIAST). It is an optical satellite with a spatial resolution of 0.75 m for the visible and near infrared bands.

Finally, one of the most intriguing launches involves three satellites that form the next part of India’s CartoSat mission. These satellites will carry both high resolution multi- spectral imagers and a panchromatic camera, and the mission’s focus is cartography. It’s not these three satellites that make this launch intriguing, it is the one hundred other satellites that will accompany them!

The Indian Space Research Organisation’s Polar Satellite Launch Vehicle, PSLV-C37, will aim to launch a record 103 satellites in one go. Given that the current record for satellites launched in one go is 37, and that over the last few years we’ve only had around two hundred and twenty satellites launched in an entire year; this will be a hugely significant achievement.

So there you go. Not a fully comprehensive list, as I know there will be others, but hopefully it gives you a flavour of what to expect.

It certainly shows that the EO is not slowing down, and the amount of data available is continuing to grow. This of course gives everyone working in the industry more challenges in terms of storage and processing power – but they are good problems to have. Exciting year ahead!

Small Satellites Step Forward

Artist's concept of one of the eight Cyclone Global Navigation Satellite System satellites deployed in space above a hurricane. Image courtesy of NASA.

Artist’s concept of one of the eight Cyclone Global Navigation Satellite System satellites deployed in space above a hurricane. Image courtesy of NASA.

We’re all about small satellites with this blog, after looking at the big beast that is GOES-R last week. Small satellites, microsatellites, cubesats or one of the other myriad of names they’re described as, have been in the news this month.

Before looking at what’s happening, we’re going to start with some definitions. Despite multiple terms being used interchangeably, they are different and are defined based around either their cubic size or their wet mass – ‘wet mass’ refers to the weight of the satellite including fuel, whereas dry mass is just the weight of satellite:

  • Small satellites (smallsats), also known as minisats, have a wet mass of between 100 and 500 kg.
  • Microsats generally have a wet mass of between 10 and 100 kg.
  • Nanosats have a wet mass of between 1 and 10 kg.
  • Cubesats are a class of nanosats that have a standard size. One Cubesat measures 10x10x10 cm, known as 1U, and has a wet mass of no more than 1.33 kg. However, it is possible to join multiple cubes together to form a larger single unit.
  • Picosats have a wet mass of between 0.1 and 1 kg
  • Femtosats have a wet mass of between 10 and 100 g

To give a comparison, GOES-R had a wet mass of 5 192 kg, a dry mass of 2 857 kg, and a size of 6.1 m x 5.6 m x 3.9 m.

Small satellites have made headlines for a number of reasons, and the first two came out of a NASA press briefing given by Michael Freilich, Director of NASA’s Earth science division on the 7th November. NASA is due to launch the Cyclone Global Navigation Satellite System (CYGNSS) on 12th December from Cape Canaveral. CYGNSS will be NASA’s first Earth Observation (EO) small satellite constellation. The mission will measure wind speeds over the oceans, which will be used to improve understanding, and forecasting, of hurricanes and storm surges.

The constellation will consist of eight small satellites in low Earth orbits, which will be focussed over the tropics rather than the whole planet. Successive satellites in the constellation will pass over the same area every twelve minutes, enabling an image of wind speed over the entire tropics every few hours.

Each satellite will carry a Delay Doppler Mapping Instrument (DDMI) which will receive signals from existing GPS satellites and the reflection of that same signal from the Earth. The scattered signal from the Earth will measure ocean roughness, from which wind speed can be derived. Each microsatellite will weigh around 29 kg and measure approximately 51 x 64 x 28 cm; on top of this will be solar panels with a span of 1.67 m.

The second interesting announcement as reported by Space News, was that NASA is planning to purchase EO data from other small satellite constellation providers, to assess the quality and usability of that data. They will be one-off purchases with no ongoing commitment, and will sit alongside data from existing NASA missions. However, it is difficult not to assume that a successful and cost effective trial could lead to ongoing purchases, which could replace future NASA missions.

It’s forecast that this initiative could be worth in the region of $25 million, and will surely interest the existing suppliers such as Planet or TerraBella; however, in the longer term it could also attract new players to the market.

Finally in non NASA small satellite news, there was joint announcement at the start of the month by the BRICS states (Brazil, Russia, India, China and South Africa) that they’d agreed to create a joint satellite constellation for EO. No further detail is available at this stage.

Once again, this shows what a vibrant, changing and evolving industry we work in!

GOES-R Goes Up!

Artist impression of the GOES-R satellite. Image courtesy of NASA.

Artist impression of the GOES-R satellite. Image courtesy of NASA.

On Saturday, 19th November, at 10.42pm GMT the Geostationary Operational Environmental Satellite-R Series (GOES-R) is due to be launched from Cape Canaveral in Florida, USA.

The GOES-R is a geostationary weather satellite operated by the National Oceanic & Atmospheric Administration (NOAA) Department of the US Government. It will the latest in the NOAA’s GOES series of satellites, and will take the moniker GOES-16 once it is in orbit, joining the operational GOES satellite constellation comprising of GOES-13, GOES-14 & GOES-15.

It will be put into a geostationary orbit at around 35 800 km above the Earth which will allow it to match the Earth’s rotation, meaning that it will effectively stay over a specific point on the Earth. It will be located approximately at 137 degrees West longitude, and through the constellation will provide coverage for North, Central and South America together with the majority of the Atlantic and Pacific Oceans.

Artists impression GOES-R satellite and its instruments. Image courtesy of NASA.

Artists impression GOES-R satellite and its instruments. Image courtesy of NASA.

The instrument suite aboard the satellite has three types: Earth facing instruments, sun facing instruments and space environment instruments.

Earth Facing Instruments: these are the ones we’re most excited about!

  • Advanced Baseline Imager (ABI) is the main instrument and is a passive imaging radiometer with 16 different spectral bands: two visible bands – Blue and Red with a spatial resolution of 0.5km, four near-infrared with spatial resolutions of 1 km; and ten infrared bands with a spatial resolution of 2 km. As its in a geostationary orbit its temporal resolution is extremely high with the full mode being where the Western Hemisphere is imaged every 5 – 15 minutes, whereas in its Mesocale mode (providing a 1000 km x 1000 km swath) the temporal resolution is only 30 seconds.
  • Geostationary Lightning Mapper (GLM) is, as the name suggests, an instrument that will measure total lightning, and both in-cloud and cloud-to-ground lightning across the Americas. It is an optical imager with a single spectral band of 777.4 nm which can detect the momentary changes in the optical scene caused by lightning. The instrument has a spatial resolution of approximately 10 km.

Sun Facing Instruments

  • Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS) instrument has two sensors to monitor solar irradiance in the upper atmosphere; these are the Extreme Ultraviolet Sensor (EUVS) and the X-Ray Sensor (XRS).
  • Solar Ultraviolet Imager is a telescope monitoring the sun in the extreme ultraviolet wavelength range.

Space Environment Monitoring Instruments

  • Space Environment In-Situ Suite (SEISS) consists of four sensors:
    • Energetic Heavy Ion Sensor (EHIS) to measure the proton, electron, and alpha particle fluxes at geostationary orbit.
    • Magnetospheric Particle Sensor (MPS) is a magnetometer measuring the magnitude and direction of the Earth’s ambient magnetic field; and has two sensors the MPS-LO and MPS-HI.
    • Solar and Galactic Proton Sensor (SGPS) will, as the name indicates, measure the solar and galactic protons found in the Earth’s magnetosphere.
  • Magnetometer will measure of the space environment magnetic field that controls charged particle dynamics in the outer region of the magnetosphere.

The ABI instrument is the most interesting to us in terms of Earth observation, and it will produce a remarkable 25 individual products including Aerosol Detection, Cloud and Moisture Imagery, Cloud Optical Depth, Cloud Particle Size Distribution, Cloud Top Measurements, Derived Motion Winds & Stability Indices, Downward Shortwave Radiation at the Surface, Fire/Hot Spotting, Hurricane Intensity Estimation, Land Surface Temperature, Moisture & Vertical Temperature Profiles, Rainfall Rate, Reflected Shortwave Radiation at the Top Of Atmosphere, Sea Surface Temperature, Snow Cover, Total Precipitable Water and Volcanic Ash. If you want to look at the details of specific products then there are Algorithm Theoretical Basis Documents (ABTDs) available, which are like a detailed scientific paper, and can be found here.

The GOES-R is the first in a series of four satellites to provide NOAA with improved detection and observation of environmental events. It is not a cheap series of satellite, with the cost of developing, launching and operating this series estimated to be around $11 billion. However, this will provide observations up to 2036.

We’re excited by this launch, and are looking forward to being able to utilise some of this new generation weather information.

Gliding Across The Ice

ESA’s Earth Explorer CryoSat. Image courtesy of ESA/AOES Medialab.

ESA’s Earth Explorer CryoSat. Image courtesy of ESA/AOES Medialab.

There’s been a flurry of reports in the last couple of weeks, reporting melting ice and retreating glaciers in Greenland and the Himalayas respectively.

A paper by McMillan et al (2016), titled ‘A high-resolution record of Greenland mass balance’ and published in Geophysical Research Letters earlier this month, highlighted that Greenland’s melting ice has contributed twice as much to sea level rise than in the previous twenty years. The research used CryoSat-2 radar altimetry between 1 January 2011 and 31 December 2014 to measure elevation changes in the Greenland ice.

The main instrument on ESA’s CryoSat-2 satellite is a Synthetic Aperture Radar (SAR)/Interferometric Radar Altimeter known as SIRAL, although also carries a second version of this instrument as a back-up. The SIRAL instrument has been enhanced to detect millimetre changes in the elevation of both ice-sheets and sea-ice. It sends out bursts of radar pulses, with an interval of 50 μs between them, covering a 250 m wide strip of the Earth and measures the time of the return signal to determine the height of the satellite above the Earth. It requires a very accurate measurement of its position to calculate this, and so it also carries a Doppler Orbit and Radio Positioning Integration by Satellite (DORIS) instrument to determine its orbit.

The research team discovered that the Greenland Ice Sheet lost an average of 269 ± 51 Gt/yr of snow and ice during the investigative period, which compared well with other independent measurements from sensors such as the Gravity Recovery and Climate Experiment (GRACE) satellite and results from climate models. This snow and ice loss corresponds to a 0.75 mm contribution to global sea-level rise each year.

It was reported this week that research undertaken by the Indian Space Research Organisation, Wadia Institute of Himalayan Geology and other institutions have revealed that the majority of the glaciers in India are retreating; albeit at different rates. Using remote sensing data up to 2006, the study looked at 82 glaciers in the Bhagirathi and Alaknanda river basins and found that there had been an overall loss of 4.6% of the glaciers within the region. The Dokriani glacier in Bhagirathi is retreating between 15 and 20 metres per year since 1995, whereas the Chorabari glacier in the Alaknanda basin is retreating 9-11 metres per year.

It’s interesting to read the retreating glacial picture alongside the research published by Schwanghart et al (2016), titled ‘Uncertainty in the Himalayan energy–water nexus: estimating regional exposure to glacial lake outburst floods’, in Environmental Research Letters. Here the research team completed the first region wide risk assessment of floods from glacial lakes, even though this only covered around a quarter dams in the Himalaya’s. The study mapped 257 dams against more than 2,300 glacial lakes within the region and found that over 20% of the dams are likely to be overwhelmed with flood water as rock systems that surround glacier-fed lakes fail. Due to the hydro-electric power needs of the region, more dams have been built in recent years, putting them closer to glacier-fed lakes.

The potential danger of this issue is demonstrated by the collapse of Zhangzangbo, a glacier-fed lake in southern Tibet, in 1981 where 20 million cubic meters of floodwater damaged hydroelectric dams and roads causing damage of approximately $4 million.

These three reports also show the potential danger melting ice and glaciers pose both locally and globally. Remote sensing data, particularly from satellites such as CryoSat-2, can help us monitor and understand whether this danger is increasing.