Cresting Wavelength 2014

Today is the final day of the Remote Sensing and Photogrammetry Society’s (RSPSoc) annual Wavelength Conference for students and early career professionals in remote sensing and photogrammetry. This year, Pixalytics was one of the sponsors of the conference, which was well attended by students from many international and UK universities, as well as representatives from a number of commercial remote sensing service providers and consultancies.

Over the three day event, keynote speakers and student poster presentations served to illustrate the infinite number of possible applications for remote sensing. One really interesting application was presented Emily Norton, a PhD student at Bournemouth University. She is an experienced forensic anthropologist with the inforce Foundation, which is a charity focussed on providing the forensic expertise for the scientific detection, recovery and identification of victims arising from mass fatality incidents, genocide, war crimes and similar crimes against humanity. Emily has previously worked in Rwanda investigating reports of mass graves following the 1994 genocide. Usually forensic work is intelligence led, but local reports are often imprecise and spatial data is needed to pinpoint graves. Once graves are located, forensic investigation is used to support war crime tribunals and, most importantly, return remains to families for proper burial.

Following the outbreak of foot and mouth disease in 2001 in the UK, thousands of livestock animals were destroyed and buried at sites across the country. Emily has used Landsat imagery of these animal graves as a basis to study the changes in vegetation at each site; the research she’s done means these principles could be used to detect clandestine mass graves in areas of conflict. Emily won the best poster competition at this year’s conference, and will travel to Bosnia later this year to test the remote sensing method further and begin to develop a streamlined standardised approach which can be used in developing countries to support future humanitarian efforts. With global coverage, a historical archive and the ability to be used safely in remote or high risk areas; remote sensing could be a valuable tool in this area of work.

One of the consistent themes of this year’s conference is that advances in technology mean that remote sensing equipment is becoming smaller, lighter, cheaper and more accurate, enabling a wider variety of remote sensing data to be collected. One of the most interesting features of the earth observation community is that each advance in technology drives new areas of research which, in turn, uncover new uses for remote sensing data, which then demands new technology! Hopefully, ESA’s Sentinel satellites will continue this cycle and inspire a new generation of remote sensing scientists; here’s to Wavelength 2015!

Blog by Bryony Hanlon, work placement student at Pixalytics Ltd and an attendee at Wavelength 2014.

The UK needs an Earth Observation Day!

Not sure if you know, but today – April 9th – is Earth Observation Day in America!

Any celebration of Earth Observation has our support, but this particular initiative deserves promotion as it’s focussed on inspiring students, and teachers, to engage with remote sensing applications; something that’s at the heart of our company too.
The event is the brainchild of a non-profit organisation called AmericaView; whose aim is to advance the availability, timely distribution, and widespread use of remote sensing data and technology through education, research and outreach, and sustainable technology transfer to the public and private sectors.

The day itself focuses on using remote sensing imagery and in-situ measurements to explore surface temperature for different types of land cover using Landsat imagery; as it’s freely available and has a historical archive. The AmericaView website has exercises and factsheets to support activities for kindergarten to year 12. In addition, AmericaView scientists, who have expertise in remote sensing and geospatial technology, support teachers in their local area by giving talks, helping teachers design lessons or being available to answer student’s questions.

We think this is a brilliant way to get students learning about remote sensing, and using lots of elements of the science, technology, engineering and mathematics (STEM) curriculums. We wondered why we don’t have something similar in the UK?

We know there are similar events, for example the Royal Geography Society has been running a GIS (Geographical Information Systems) Day for a number of years; and the National STEM Centre supported World Meteorological Day on the 23 March that looked at weather and climate change. However, there is far more to remote sensing and Earth Observation than weather. We need to promote the potential for the subject to support crop management, helping disaster response, forestry use, support water and marine management, urban planning, flood prevention … the list could go on!

Earth Observation offers huge potential to help our understanding of this planet and its natural resources. With the introduction of cubesats, swarm satellites, and last week’s successful launch of the first satellite of ESA’s Copernicus mission, data available is going to increase exponentially in the near future. It gives students opportunities enhance learning, and apply skills, in a variety of subjects beyond the obvious STEM ones. Remote sensing could be used in the teaching of geography, history and even politics. Couple this with the ambition to double the size of the UK space sector by 2020, Earth Observation could not only supports learning, but offers realistic opportunities for future jobs and careers.

We need to interest, excite and, most importantly, inspire the next generation of scientists in this country, and an educational based Earth Observation Day could play an exciting part of that development. What does the rest of the Earth Observation community think? Should we get our voice heard for an Earth Observation day here too?

How Many Satellites are Orbiting the Earth?

As we discussed last week, the European Space Agency (ESA) Sentinel-1A satellite is due to be launched tomorrow night from Europe’s Spaceport in Kourou, French Guiana. This got me wondering, how many satellites are orbiting the earth?

It turns out there are two organisations who can help answer this question; the Union of Concerned Scientists (UCS) and the United Nations Office for Outer Space Affairs (UNOOSA).

The UCS is a non profit alliance of citizens and scientists working to design innovative solutions to the world’s challenges. On their website they maintain a database of active satellites; alongside information on their ownership, purpose and vital statistics.

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

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

According to the UCS database, as of the 31st January 2014, there were 1,167 active satellites in orbit. Of these sixty-one have a purpose defined as Earth Observation, a further sixty-eight are defined as remote sensing, fourteen as meteorology and forty-nine relating to earth science. This gives almost two hundred satellites providing information about our planet, one must have data you could use and benefit from?

Fifty percent of the active satellites are in low earth orbits, at altitudes between 160km and 2,000km, and they take between ninety and one hundred and twenty minutes to orbit the earth. Almost forty percent are in geo-synchronous orbits between 35,000km and 36,000km altitudes, taking one day to orbit. The remainder are either in medium earth or elliptical orbits.

Satellites are generally owned by governmental bodies or private corporations; interestingly over 30 universities own satellites. There are fifty five countries who can claim to be in space, others may also make that claim through the eighty satellites managed by multi-national agencies such as ESA. The USA are leading the orbital land grab with links to over 500 satellites, significantly more than any other country; Russia and China are next linked to over one hundred. The UK has links to twenty seven; whilst ESA has eighteen satellites and has co-launched three others.

Whist the UCS database deals with active satellites; UNOOSA keep track of every satellite launched, including manned missions. Established in 1958, its website has a searchable Online Index of Objects Launched into Outer Space. The oldest satellite in orbit is Vanguard 1 which was launched on the 17th March 1958. In total, the UN index lists 6,907 launched satellites, 2,931 of which have decayed and fallen back to earth, and 38 whose fate is unknown! Therefore currently 3,921 satellites are circling the earth, meaning there is almost 2,800 pieces of junk metal up there!

Last year saw the greatest number of launches in a single year with 208. With NASA recently launching Flock 1, a fleet of 28 Earth Observation cubesats; there have already been 56 new objects launched this year. It’s clear the space sector is a thriving industry, and Earth Observation is an important part. When are you going to join in? Get in touch if you want to know more.

Copernicus ready for lift off!

The first satellite of the European Union’s Copernicus project, Sentinel-1A, is due to be launched next Thursday, April 3rd. The project aims to create a constellation of satellites providing a range of Earth Observation data to aid our understanding, and management, of the planet and its resources.

Sentinel-1 is a two-satellite mission, with a second identical satellite, Sentinel-1B, due to be launched in 2016.  The two satellites will orbit the earth 180° apart, allowing the entire globe to be covered every six days, although the Artic will be revisited every day and Europe, Canada and main shipping routes every three days.

The Sentinel-1A satellite weighs 2,300kg and carries a 12m long C-band Synthetic Aperture Radar (SAR) instrument; this is an advanced radar system that transmits microwave radiation that allows it to capture images of the earth twenty four hours a day, in addition it get images through cloud and rain. This is particularly useful when providing imagery for emergency response during extreme weather conditions. The satellite also has a pair of 10m solar wings to provide independent power, the deployment sequence can in be seen in this European Space Agency video.

Over land Sentinel-1 will capture data in an Interferometric Wide swath mode, which means it takes three scans and then combines them into a single image. Each scan has a width of 250km and a spatial resolution of 5m x 20m, which means each pixel on the image represents a 5m x 20m area. It works slightly different over the oceans, operating on a 5m x 5m spatial resolution enabling the direction, wavelength and heights of waves on the open oceans to be determined.

Image of the port of Maracaibo (Venezuela) using ASAR imagery; courtesy of ESA

Image of the port of Maracaibo (Venezuela) using ASAR imagery; courtesy of ESA

This satellite will replace the ASAR (Advanced Synthetic Aperture Radar) C-band instrument that was on-board the Envisat mission which had a resolution of 150m; until contact was lost in April 2012. The image on the right is of Lake Maracibo in Venezuela, and was  acquired in ASAR Image Mode Precision with a spatial resolution of 12.5 m. The varying colour is created by assigning a different RGB (Red, Green, Blue) colour to different acquisition dates (8 Sep 2004 is red, 26 Feb 2004 is green and 17 Jun 2004 is blue) with the brightness being linked to surface texture, so the rougher the surface the brighter the image

Lake Maracaibo itself is also really interesting.  It was formed 36 million years ago and is the largest natural lake in South America; although it has a direct connection to the ocean and so could be called an inland sea. The port of Maracaibo, located on the west side of the strait (large bright area on the image), is the second city of Venezuela and the lake is also a petroleum-producing region supplying two-thirds of the total Venezuelan petroleum output. However, its biggest claim to fame is atmospheric phenomenon of a semi-permanent lightning storm where the Catatumbo river flows into the lake; making it a magnet for stormchasers the world over.

Our country is shrinking

As an island nation, coastal erosion through waves, sediment and rocks hitting the shore should be a major concern to everyone. Earlier this year images of the Dawlish sea wall being destroyed and the dangling railway line grabbed the headlines about the power of the ocean; however the severe weather also resulted in many areas of the UK experiencing accelerated rates of coastal erosion.

The Environment Agency notes that 28% of the coast of England and Wales erodes by more than 10cm per year in normal circumstances, but the speed of erosion varies from area to area and can sometimes be more. This winter it has been estimated that parts of the coastline have suffered seven years worth of erosion in just a couple of months.

False colour image of coastline at Happisburgh, Norfolk. The red line indicates the cliff edge in 2003, the dark grey line indicates the current cliff edge in 2014 and the beach is shown as a white/light grey area. Image courtesy of the U.S. Geological Survey (based on 15 m resolution).

False colour image of coastline at Happisburgh, Norfolk. The red line indicates the cliff edge in 2003, the dark grey line indicates the current cliff edge in 2014 and the beach is shown as a white/light grey area. Image courtesy of the U.S. Geological Survey (based on 15 m resolution).

Happisburgh in Norfolk is particularly vulnerable to this effect. On 11 December 2013 the BBC reported that following the tidal surge on the east coast, almost two metres of land in the Beach Road area was lost. This left a cliff top bungalow dangerously unstable and sadly, the property had to be demolished shortly after. This area has been studied for many years by scientists, including those from the British Geological Society and between 1992 and 2007 they measured approximately one hundred and twenty five metres of land lost to the sea. On the right Landsat imagery has been used to compare the position of the coastline in 2003 with that of the present day. This can be further supplemented by ground measurements or higher resolution satellite imagery where necessary to provide extra detail.

The speed of erosion is affected by a range of factors including the underlying geology, sea levels, weather patterns and coastal defences; even the type of dredging we discussed last week can contribute by changing natural sea defences. Being able to predict what is happening to a coastline is vital to local residents, landowners and town planners; but it’s also critical to bodies, such as the Environment Agency, who decide where to spend money. Protecting the entire coastline isn’t practical, and when coupled with limitations on finances, it’s clear decision makers have an unenviable task of determining which areas should be prioritised for maintenance or construction of sea defences; and which should not.

Earth observation data provides a vital resource to support coastal management. With forty years of historical images captured, erosion rates can be measured over time and the effectiveness of sea defences evaluated.  We can provide you with imagery and support to develop, and enhance, your coastal monitoring programme from £250.  With the ferocity, and frequency, of storms predicted to increase coastal erosion is set to be high up the agenda for many years.

Blog produced by Bryony Hanlon, work placement student with Pixalytics, and Andy Lavender.

The Question of Dredging

Dredging has been a hugely contentious issue in the UK ever since the St Jude’s storm hit the country on the 28 October 2013; this marked the beginning of a relentless winter weather pattern of heavy rainfall and high winds. This severe weather coupled with coastal surges breaching flood defences led to large parts of the UK to be under water – a situation that still exists for significant parts of Somerset. Satellite data was used to map the flooded areas as part of the flood response by UK government agencies; more details can be found in our post Is the Southern UK Flooding a Disaster?

As the flooding occurred local communities bemoaned the lack of river dredging in recent times, and they felt this was a significant contributing factor for the rising water levels. In Prime Minister’s Questions on the 29th January this year, David Cameron announced that once flood waters in Somerset had drained away, rivers in the county will be dredged. Dredging itself also creates problems, releasing suspended sediment into the river water and secondly the need to get rid of the dredged material.

Image of East Devon, UK taken by Landsat 8 on 4th November 2013.  The River Exe flows from top to bottom and the River Teign from left to right. Plumes of suspended sediment are clearly visible following periods of heavy rainfall in late October and early November 2013.  Image courtesy of the U.S. Geological Survey

Image of East Devon, UK taken by Landsat 8 on 4th November 2013.

The River Exe flows from top to bottom and the River Teign from left to right. Plumes of suspended sediment are clearly visible following periods of heavy rainfall in late October and early November 2013.

Image courtesy of the U.S. Geological Survey

In addition to flood mapping, satellite data can also be used to map and monitor sediment transported. The Landsat 8 image on the right shows the plumes of sediment visible around the east Devon coastline just one week after the St. Jude’s storm. Since 1972 the Landsat mission has continuously monitoring the Earth’s surface; and makes this information freely accessible for use across a range of sectors.

This week it was announced that dredging of the River Tamar, on the border between Devon and Cornwall, will continue for the next two years in order to keep the channels clear for access to Devonport Dockyard. The silt from this process will be deposited in Whitsand Bay, Cornwall, despite the area being designated as a Marine Conservation Zone.

Dredging is a tool coming back into the UK flood defence armoury; the benefits, and potential harm, will be monitored closely in the coming months and years.

Next week’s we’ll be looking at the accelerated coastal erosion from the winter storms.

Blog produced by Bryony Hanlon, work placement student with Pixalytics, and Andy Lavender.

Home from Hawaii

I got back to a ‘cold’ UK on Saturday afternoon after spending last week at Ocean Sciences 2014.  It was a fantastic conference with over 5,600 attendees.  My scientific highlights were:

The Surface Ocean Layer Atmosphere Study (SOLAS) session on Monday where speakers presented research on the sea surface microlayer (the top 1 mm of the ocean); this layer is important so we can understand the transfer of compounds, such as carbon dioxide, and particles from the ocean to the atmosphere and vice versa that are critical to our interpretation of the climate.

On Tuesday afternoon it was the Optics and Light in the Particle-Laden Coastal Ocean session, with presentations focused on understanding the acoustic and optical signatures of particles, including their shape, from multi-angular measurements and Lidar (laser) profiling of a phytoplankton bloom.

My key session was obviously Optical Remote Sensing of Freshwater, Estuarine and Coastal Environments on Wednesday. I gave a presentation on Multi-Sensor Ocean Colour Atmospheric Correction for Time-Series Data.  Atmospheric correction is the removal of the atmosphere’s signal from data so only the water-leaving radiance signal is left; it allows data to be compared between days irrespective of the weather conditions of that day – so an image taken on a hazy day will look like it was taken on a clear day.

HICO™ Data, image of Hong Kong from the Oregon State University HICO Sample Image Gallery, provided by the Naval Research Laboratory

HICO™ Data, image of Hong Kong from the Oregon State University HICO Sample Image Gallery, provided by the Naval Research Laboratory

Other interesting talks from this session included Tiit Kutser’s presentation on comparing in-situ measurements with MERIS data for dissolved organic carbon and iron concentrates in Lake Malaren in Sweden, Keping Du’s retrieval algorithm for phycocanian, a pigment within cyanobacteria, within Taithu lake in China, Heidi Dierssen’s optics of seagrass for remote sensing and I also really enjoyed my mentee Guangming Zheng’s presentation on suspended sediment within Chesapeake Bay, off the west coast of America – this took me back to my PhD that focussed on the suspended sediment plume from the River Humber.

Finally, there were great presentations by Curt Davis and Nick Tufillaro on the Hyperspectral Imager for the Coastal Ocean (HICO) mission. It’s an experimental mission that’s designed to sample the coastal ocean; one 50 x 200 km scene per orbit at a spatial resolution of around 90 m. The image on the right shows a HICO example.

On top of these oral sessions, I also spent time in the exhibition, poster sessions and some of the evening events.  My last event on the Thursday evening was about getting involved in the European Commission’s Horizon 2020 Research programme – so if anyone needs an Earth Observation specialist partner for their bid, get in touch!

Settling in at the 2014 Ocean Sciences Meeting

My beach reading spot!

My beach reading spot!

I’m feeling a bit guilty writing this with everyone in the UK still experiencing the wet wintery weather, as I’m in Honolulu, Hawaii at the 2014 Ocean Sciences Meeting. I arrived around midnight last Friday and spent Saturday morning relaxing on the edge of Waikiki beach looking out to sea, watching people go by and reading a book; and I’d recommend Mr Penumbra’s 24-Hour Bookstore by Robin Sloan as a great story if you’re interested technology, cryptography or old books!

Ocean Sciences 2014 opened with a welcome reception on Sunday evening and an interesting key note address by Polynesian explorer Elizabeth Kapu’uwailani Lindsey entitled ‘Bringing the Wisdom of the “Elders” Together with Modern Science for the Future of the Environment’.  During the evening I did try to try track down the three people I’m mentoring at this conference – Elaine, Guangming and Navid. However, as there are over 5,000 attendee’s there were a lot of people to search through!

I finally sat down with my mentees at breakfast on Monday morning. The meeting’s mentoring program is an interesting concept designed to help novice conference attendees get the most value out of their experience.

Yesterday we met up at Navid’s poster to discuss his work on modelling internal waves, at lunch we discussed Elaine’s poster on climate data services and tomorrow Guangming is presenting a talk on the turbidity maximum in Chesapeake Bay in the same session as I’m presenting my ocean colour atmospheric correction work. This is a great element about going to scientific conferences, meeting people to discuss their research and interests. Some are new acquaintances and some I’ve known for a long time. My first time attendance at this meeting (also in Hawaii) was in 2006.

Today I’ve also been to a session on particles in the coastal ocean, and this evening it was Philanthropic Investment in Ocean Research. Tomorrow I’ve got a really busy day as I’m speaking, I’ll give you an update on the second half of the conference next week!

A little addendum I noticed while finishing this post is that Satellite Applications Catapult yesterday published its response to UK Space Innovation and Growth Strategy Space Growth Action Plan. I’ve downloaded it, and it will form part of my next beach reading session!

Time to Use Historical Data?

Last week we noted how Earth Observation can be used for real-time disaster support, this week we are looking at another significant advantage of Earth Observation, namely historical data.

In-situ measurements are great for right now, and some in-situ measurements do offer historical comparisons. But what if you want to look at something, or somewhere that has not been measured before, or you want information before in-situ measurements started at a site? This is where the archive of satellite imagery comes into its own; where you can go back in time and undertake historical measurements, monitoring and research. So how far back can you go?  Earth Observation technically began in the 19th Century; Gaspard-Felix Tournachon took photographs of Paris from his balloon in 1858 and Alfred Nobel, yes the man of the prize, designed a system to take aerial photographs from a rockets in 1896. Sadly, Nobel died four months before his design took the first photographs in April 1897.  Obviously we can’t go quite this far back!

Landsat Image Courtesy of USGS and NASA

Landsat Image Courtesy of USGS and NASA

Developments in satellite technology took place in the mid-20th Century, with the launch of the Explorer VII satellite in 1959 designed to measure the amount of heat reflected by the earth; and in 1960 the TIROS 1 weather satellite was sent up to produce daily cloud formation images. The first real mapping satellite was the Earth Resources Technology Satellite in 1972 – later renamed to Landsat. Over the years a series of Landsat satellites have been launched, the latest being Landsat 8 last year.  Consequently, there is 40 year archive of Landsat imagery available!

However, before you all start planning your forty year historical data requirements you need to find out if the data you want is available. Over the years as technology has developed the variety of sensors in orbit has increased, the frequency of which each place on earth is passed over has improved and there is greater availability of spectral bands and spatial resolution. All of this gives richness of imagery and data available today, that may not have a long historical tail.

Some imagery is freely available, whilst for others you may be required to pay a fee for access.  These fees can range from ten to twenty pounds for a basic image up to many thousands for a single high resolution image.  Interestingly the French Space Agency, CNES, announced last month that they had agreed to offer free access their Spot Optical Earth Observation data archive for images at least five years old.

Earth observation archives offer a huge amount of data and imagery.  To use it you need to know what is available, where to find it, what it costs and crucially how to interpret it to ensure consistency and comparability across the time period you are using.  So how could you, or your company, benefit from this fantastic resource? If you want to discuss your needs, please get in touch.

Is the Southern UK Flooding a Disaster?

Landsat 8 image acquired on the 23 January 2014 showing the floods within Somerset, UK, with the river Parrett flowing into the Bristol Channel in the top left corner; courtesy of the USGS and NASA.

Landsat 8 image acquired on the 23 January 2014 showing the floods within Somerset, UK, with the river Parrett flowing into the Bristol Channel in the top left corner; courtesy of the USGS and NASA.

Over the last couple of months flooding has impacted the southern half of the UK. Coastal surges affected the South East of England in early December and the Somerset levels became flooded in the middle that month; and they remain flooded. The South West was battered by huge waves and rain at start of February – you may have seen the dangling railway lines in Dawlish, which is our main rail connection to everywhere north of Plymouth! Over the last few days the flooding has impacted communities bordering the river Thames and river Severn. Further rainfall, tidal surges, river flooding and ground water flooding means parts of UK are likely to be ‘under water’ for many months to come. Is this a disaster?

The Oxford Dictionary describes a disaster as a sudden accident or a natural catastrophe that causes great damage or loss of life – the current scenario seems to fulfil this definition. In the UK the Prime Minster is taking charge by chairing COBRA Meetings. Whilst COBRA sounds really impressive, COBRA actually stands for Cabinet Office Briefing Room A; and so less impressively, it’s only referring to the room the meeting is in! However, COBRA is the emergency committee coordinating the Government and associated agencies response to the flooding situation. COBRA is meeting regularly, is it a disaster?

The Earth Observation community considers the UK is experiencing a disaster. This was recognised by the activation of the International Charter: Space and Major Disasters on the 6th February for flooding in South West England. When this charter is activated, space agencies around the world use their resources to collect satellite datasets that can be used to help mitigate the effects on human life and property.

Earth Observation offers the opportunity to see the big picture, something that is usually difficult in disaster situations, as well as what is happening at street level. It gives governments, civil protection agencies and international relief organisations key information to assist their decision-making processes. The UK Space Agency works in collaboration with DMCii (a subsidiary of SSTL that operates the Disaster Monitoring Constellation) to contribute imagery with a recent image showing the flooding in Somerset.

In 2013 there were 38 activations of the Disaster Charter. Flooding in the UK also activated the charter on the 6th January this year and the 4th December last year. Since the 6th February there have been three further activations of the charter on the 7th for Floods in Zimbabwe, on the 10th for snowfall in South Korea and on 11th for a flood and landslide in Burundi.

With weather patterns evolving around the globe, the activation frequency of this charter is likely to increase. Earth Observation supports the observation, and management, of the planet and its natural resources; and supporting disaster relief situations is one of its most beneficial uses.