Celebrating Landsat & the Winter Olympics

First Landsat image acquired in 2013 showing area around Fort Collins, Colorado. Data courtesy of NASA/USGS.

The Landsat programme achieved a couple of significant milestones over the last two weeks. Firstly, the 11th February marked the five year anniversary of the launch of Landsat 8 which took place at the Vandenberg Air Force Base, California, in 2013. The image to the right is the first one acquired by Landsat 8 and shows the area around Fort Collins, Colorado with the Horsetooth Reservoir very clear left of centre.

This anniversary is an interesting one because Landsat 8 was only designed for an operational life of five years. Obviously it has already exceeded this and these planned lifespans are very conservative. More often the amount of fuel on board is a more relevant assessment for lifespan and for Landsat 8 the initial assessment was a 10 year lifespan. However, even this tends to be a conservative estimate. As an example, nineteen years ago Landsat 7 was launched with similar planned operational lifespans. It is still working today, although there have been some degradation issues, and IT achieved its own significant milestone on the 1st February when it completed its 100,000th orbit of the Earth.

Landsat 8 is in a sun-synchronous orbit at an altitude of 705 km, circles the Earth every 98.9 minutes and in the last five years has undertaken over 26,500 orbits according to NASA who have produced a short celebratory video.

It has two main instruments, an Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS), which together measure eleven different spectral bands. The TIRS has two thermal bands which are used for sensing temperature, whereas the OLI measures nine spectral bands:

  • Three visible light bands that approximate red, green and blue
  • One near infrared band
  • Two shortwave infrared bands
  • Panchromatic band with a higher spatial resolution
  • The two final bands focus on coastal aerosols and cirrus clouds.

With the exception of the highest polar latitudes, Landsat 8 acquires images of the whole Earth every 16 days which has meant it has acquired over 1.1 million images of the Earth that accounts for 16 percent of all the data in the Landsat multi-mission archive.

Landsat 8 image of Pyeongchang, South Korea, which is hosting the 2018 Winter Olympics. Data acquired 11th February 2018. Data courtesy of NASA/USGS.

The image to the left is the Pyeongchang region of South Korea where the Winter Olympics are currently taking place acquired by Landsat on its five year anniversary on the 11th February. Pyeongchang is in the north west of South Korea in the TaeBaek Mountains just over one hundred miles from the capital, Seoul. The left area of the image shows the mountain range where the skiing, biathlon, ski jumping, bobsled, luge and skeleton events take place and to the right is the coastal city of Gangneung, where the ice hockey, curling, speed skating and figure skating are taking place.

With its forty-five year archive, Landsat offers the longest continuous dataset of Earth observations and is critical to researchers and scientists. Landsat 9 is planned to be launched in 2020 and Landsat 10 is already being discussed.

Congratulations to Landsat 7 and 8, and we look forward to many more milestones in the future.

Flywheels Spinning At Data.Space

The Data.Space Conference took place last week in Glasgow. It was an interesting, thought-provoking and useful event, which felt very friendly and was distinguished by the seniority of the attendees with a lot of companies were represented by CEO’s, MD’s and owners/founders.

The event began with the session ‘Listening to our Earth’ with presentations from Spire, Hawkeye360, KSAT, CGI UK and Promos Ventures. We were particularly caught by the idea from Peter Platzer of Spire, who talked about the flywheel and how you need to build momentum within companies to move from good to great, in particular focussing on making a tenfold improvement on what currently exists.

Sam gave her presentation in the second session on ‘Looking at our Earth’, which can be accessed here. We found it encouraging that some of the key messages that we picked out were echoed by other presenters, both in this session and others. The common themes highlighted included:

  • Stop focussing on imagery, and focus more on customer needs.
  • Demonstrate the problem that the Earth Observation (EO) data solves and the value it adds.
  • The fact that the data comes from space isn’t critical to the customer.

We had a number of people come up after Samantha’s presentation to say how much they enjoyed it, which is always good! Interestingly, hers was not the only presentation that Pixalytics got mentioned in. Our blog on ‘Earth Observation Satellites in Space’ was name checked by Will Cadell, CEO of Sparkgeo, in the session after lunch. A highlight of which was Grega Milcinski, CEO Sinergise, demonstrating the possibilities of the Sentinel Hub and how they are making a lot of their code available on GitHub to enable others to build on it.

The second day began with a thought provoking session on using EO to create a better planet. Temporal resolution, file sizes, lack of internet facilities and the need to have quick simple maps was highlighted as a challenge to using EO data in disaster relief scenarios. Access to datasets was highlighted by Tony Long, Global Fishing Watch, as a barrier to providing a planet wide view of what is happening. It was also great to listen to Steve Lee from Astrosat talk about their experiences of two UK Space Agency International Partnership Programme projects, and pick up some pointers for the ones we’re involved in.

As a micro company, the second session of this day was fascinating to us giving an overview of what investors and venture capital people look for in companies. It was heartening to hear that data analytics is seen as having a lot of value, but less positive was that the vast majority of funding in this area is going into the US. It was also noted that these funders aren’t interested in funding research, they want to get in on the ‘Last Mile’ of a product or service – making us wonder whether we would ever be attractive to investors!

Pixalytics Stand at Data.Space

Throughout the conference we manned our small table, surrounded by companies with the obligatory pop-up banners. We stood alone bare backed as we flew to Glasgow on Easyjet and a pop-up banner would have been an extra bag! We had lots of interesting conversations over potential collaborations, new customers, product ideas and solutions to challenges; and we even managed to sell a couple of copies of our book! We were able to demonstrate our portal, and we got some really good feedback. We’ll be looking for more feedback and some beta testers over the coming weeks – please get in touch in you’re interested! Finally, we‘d also like to commend the fantastic food offering at the event, which had lots of lovely Scottish notes.

Overall, this was a great event and we’ll certainly be looking to go back next year!

Five Learning Points For Developing An Earth Observation Product Portal

Landsat mosaic image of the Isle of Wight. Data courtesy of NASA.

This week we’re gently unveiling our Pixalytics Portal at the DATA.SPACE 2018 Conference taking place in Glasgow.

We’ve not attended DATA.SPACE before, but great feedback from some of the last years attendees convinced us to come. It’s an international conference focusing on the commercial opportunities available through the exploitation of space-enabled data and so it seemed the perfect place to demonstrate our new development.

Regular readers will know we’ve had the product portal idea for a little while, but it often went to the back of the work queue when compared to existing work, bid preparation and our other developments. Hence, six months ago we pinpointed the DATA.SPACE as our unveiling event!

On the 1st and 2nd February at Technology & Innovation Centre in Glasgow we have a stand where we’re inviting everyone to come up and have a look at the portal and give us feedback on the idea, principles and the look and feel of the portal.

We’re demonstrating five products, and we’re looking to expand this, these are:

  • Landscape Maps of the UK
  • Water Extent Mapping
  • Flood Water Mapping
  • Coastal Airborne Lidar Survey Planning Datasets
  • Open Ocean Water Quality Parameters

We’re not just attending, we’re exhibiting and Sam’s presenting!! So we’re going to have the full triumvirate conference experience. Sam is presenting in the first day’s second session titled ‘Looking at our Earth’ which starts at 11.10am. Her presentation is called ‘Growing Earth Observation By Being More Friendly.’

Developing this portal to its current state has been a really interesting journey. When we began we didn’t know why some of the larger companies haven’t cracked this already! Six months later and we’ve started to understand the challenges!

We thought it might be helpful to reveal are five top learning points for any other SME’s in our industry considering developing a portal. They are:

  1. Challenging the Digital e-commerce Process: Standard digital e-commerce systems allow customers to purchase a product and then download it immediately. The need to have an additional step of a few minutes, or even hours, to undertake data processing complicates things. It means that simple off-the-shelf plug-ins won’t work.
  2. Don’t Go for Perfection: Building a perfect portal will take time. We’ve adopted the approach of Eric Ries, author of The Startup Way, who advocates building a system for ten purchases. We’re perhaps a bit beyond that, but certainly we know that this will only be the first iteration of our portal.
  3. Linking The Moving Parts: Our portal has a web-front end, a cloud processing backend and the need to download requested data. We’ve tried to limit the amount of data and processing needed, but we can’t eliminate it entirely. This means there are a lot of moving parts to get right, and a lot of error capturing to be done!
  4. Legal & Tax issues: Sorting out the products is only one part of the process, don’t forget to do the legal and tax side as that has implications on your approach. We have learnt a lot about the specific requirements of digital services in e-commerce!
  5. Have a deadline: We chose to exhibit at DATA.SPACE to give us a deadline. We knew if we didn’t have a hard deadline we’d still be debating the products to include, and have developed none of them! The deadline has moved us really close to having a portal.

If you’re at DATA.SPACE this week, please come up and say hello. If you’ve got a few minutes to spare we’d love to get you feedback on our portal.

First Light Images

Mosaic image of The Netherlands created using three Sentinel-1 scans in March 2015.
Data Courtesy of Copernicus Sentinel data (2015)/ESA.

Two of the satellites launched on 12th January by the Indian Space Research Organization (ISRO) have released their first images. We wrote about the launch two weeks ago, and wanted to follow up on their initial outputs.

The first is the exciting ICEYE-X1, which is both the world’s first synthetic-aperture radar (SAR) microsatellite and Finland’s first commercial satellite. We currently use Sentinel-1 SAR imagery for some of Pixalytics flooding and water extent mapping products and so are really interested to see what this satellite produces.

One of the key advantages of radar satellites over optical ones is that they can capture images both during day and night, and are not hampered by the presence of clouds.  However, using a different part of the electromagnetic spectrum to optical satellites means that although it is black and white image it’s sometimes easier to distinguish objects within it.

Zoomed in portion of Netherlands mosaic image created using three Sentinel-1 scans in March 2015.
Data Courtesy of Copernicus Sentinel data (2015)/ESA.

For example, the image to the left is a zoomed in portion of Sentinel-1 mosaic of the Netherlands acquired in March 2015 where you can clearly see couple of off-shore windfarms.

Sentinel-1 is a twin satellite constellation and uses a C-Band SAR on board two identical satellites. Over land it captures 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 250 km and a spatial resolution of 5 m x 20 m, with a six day repeat cycle for an area of land.

In comparison, ICEYE-X1 produced its first image with a spatial resolution of 10 m, and it’s hoped to reduce this down to 3 m. It issued its first image on Monday 15th January, three days after launch, showing part of Alaska, including the Noatak National Preserve, with a ground coverage of approximately 80 km by 40 km. The image can be seen here.

ICEYE-X1 weighs in at under a 100 kg, which is less than a twentieth of Sentinel-1 which weighed in at 2 300kg. This size reduction produces a high reduction in the cost too, with estimates suggesting it only cost ICEYE around a hundredth of the €270 million price of the second Sentinel-1 satellite.

By 2020 ICEYE is hoping to establish a global imaging constellation of six SAT microsatellites that will be able to acquire multiple images of the same location on Earth each day. After this, the company has ambitions of launching 18 SAR-enabled microsatellites to bring reliable high temporal-resolution images which would enable every point on the Earth to be captured eight times a day.

Cartosat-2F also sent its first image on the 15th January. The image, which can be found here, is of the city of Indore, in the Indian state of Madhya Pradesh. The Holkar Stadium is tagged in the centre, a venue which has previously hosted test Cricket. The satellite carries a high resolution multi-spectral imager with 1 m spatial resolution and a swath width of 10 km.

It is the seventh satellite in the Cartosat series which began in 2007, the others are:

  • Cartosat 2 launched on 10th January 2007
  • Cartosat 2A launched on 28th April 2008
  • Cartosat 2B launched on 12th July 2010
  • Cartosat 2C launched on 22nd June 2016
  • Cartosat 2D launched on 15th February 2017
  • Cartosat 2E launched on 23rd June 2017

These two satellites are just at the start of their journey, and it will be interesting to see what amazing images they capture in the future.

EO Market Is a-Changin’

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

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

Historically, if you wanted satellite Earth Observation (EO) data your first port of call was usually NASA, or NOAA for meteorological data, and more recently you’d look at the European Union’s Copernicus programme. Data from commercial operators were often only sought if the free-to-access data from these suppliers did not meet your needs.
However, to quote Bob Dylan, The Times They Are a-Changin’. NASA, NOAA and Copernicus are buying, or intending to buy, data from commercial operators.

However, as with many activities there are often precedents. For example, the SeaWiFS mission was built to NASA’s specifications and launched in 1997. It was owned by the commercial organisation Orbital Sciences Corporation and NASA conducted a ‘data-buy’. They’ve moved back in this direction last month as NASA issued a Request for Information for US companies interested in participating in the Earth Observations from Private Sector Small Satellite Constellations Pilot. The aim of this programme is to identify commercial organisations collecting EO data relating to Essential Climate Variables (ECV), and then to evaluate whether this would be a cost effective approach to gathering data rather than, or alongside, launching their own satellites.

To interest NASA the companies need to have a constellation of at least three satellites in a non-geostationary orbits, and the ECV dataset will need to include details of both instrument calibration and processing techniques used. Initially, NASA plans to provide this data to researchers to undertake the evaluation. According to Space News, 11 responses to the request had been received. Discussions will take place with responding companies over the next month and it’s anticipated orders will be placed in March 2018.

NOAA is another US agency looking to the private small satellite sector through their Commercial Weather Data pilot programme. To supplement their own data collections they’ve already purchased GPS radio occupation data and are planning to buy both microwave sounding and radiometry data.

Not everyone is aware that the Copernicus Programme also purchases data from commercial sources as part of its Contributing Missions Programme. Essentially, if data is not available for any reason from the Sentinel satellites, then the equivalent data is sought from one of 30 current contributing missions which include other international partners such as NASA, but also commercial providers.

Whilst part of the drive behind this approach is to ensure data continuity, in the US the backdrop has a more long term concern with President Trump’s intention to move NASA away from EO to focus efforts on deep space exploration. It’s not been fully confirmed yet, but there is due to be a Congress budget discussion later this week and if approved it could mean the loss of the following four NASA missions:

• Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite
• Orbiting Carbon Observatory-3 (OCO-3)
• Climate Absolute Radiance and Refractivity Observatory (CLARREO) Pathfinder
• Deep Space Climate Observatory (DSCOVR)

Whilst buying data from commercial providers may offer opportunities, it also has a number of challenges including how to buy this whilst maintaining their commitment to free-to-access data, and with the shorter lifespans of small satellites the increased pressure on calibration and validation work.

It’s clear that things are evolving in the EO market and the private sector is coming much more to the fore as a primary data supplier to researchers, national and international bodies.

Four Key Earth Observation Trends For 2018

Blue Marble image of the Earth taken by the crew of Apollo 17 on Dec. 7 1972.
Image Credit: NASA

This week we’re looking at this year’s key trends in Earth Observation (EO) that you need to know.

Rise of the Data Buckets!
EO data is big! Anyone who has tried to process EO data knows the issues of downloading and storing large files, and as more and more data becomes available these challenges will grow. Amazon recognised this issue and set up Amazon Web Services which automatically downloads all freely available data such as Copernicus and Landsat, offering people who want to process data a platform where they don’t have to download the data – for a price!

The European Commission also picked up on this and awarded four commercial contracts at the end of last year to establish Copernicus Data and Information Access Services (DIAS) which will offer scalable processing platforms for the development of value-added products and services.

The four successful DIAS consortiums are led by Serco Europe, Creotech Instruments, ATOS Integration & Airbus Defence and Space respectively, and a fifth DIAS is planned to be established by EUMETSAT. It’s hoped this will kick-start the greater use and exploitation of Copernicus data.

Continued Growth of Data
There are some exciting EO launches planned this year continuing to increase the amount of data available. Earlier this week China launched the last two satellites of the high resolution optical SuperView constellation. In addition, some of the key larger satellites going into orbit this year include:

  • ESA’s Sentinel-3B and its Aeolus wind mission.
  • NASA’s Gravity Recovery and Climate Experiment Follow-on (GRACE-FO) and the Ice, Cloud and land Elevation Satellite (ICESat-2).
  • Japan’s Advanced Satellite with New system Architecture for Observation (ASNARO 2) which is x-band SAR radar satellite with a 1 m ground resolution.
  • NOAA’s GOES-S is the second of four upgraded weather observatories.

In addition, as we described last week, cubesats will continue to have regular launches. We are still a long way from the high watershed of EO data!

SaaS Will Become The Norm
The rise of the data buckets will encourage the Software-as-a-service (SaaS) approach to EO to become the norm. Companies will develop products and services and offer them to customers on a platform via the internet, rather than the historic bespoke application approach. For companies this will be a more effective way of using their resources and will allow them to better leverage products and services. For the customers, it will enable them greater use EO and geospatial data without the need for expert knowledge.

Pixalytics is due to launch its own Product Portal at the Data.Space 2018 conference at the end of this month.

Artificial Intelligence (AI)
AI is becoming more and more important to EO. Part of this is the natural development of AI, however certain EO tasks are far more suited to AI. For example, change detection, identification of new artefacts in imagery, etc. These aspects have a base image and looking for differences, computers can do this much quicker than any human researcher. Although, it’s also true that humans can see artefacts much more easily than you can program a computer to identify them. Therefore, these AI applications are strongly dependent on training datasets created by humans.

However, things are now moving beyond these simple AI tasks and it’s becoming an integral part of EO products and services. For example, last year Microsoft launched their AI for Earth programme, support by a $50 m investment, which will deploy their cloud computing, AI and other technology to researchers around the world to help develop new solutions for the agriculture, biodiversity, climate change, and water challenges on the planet.

Summary
These are a snapshot of our view of the key trends. What do you think? Have we missed anything? Let us know.

Earth Observation’s Flying Start to 2018

Simulated NovaSAR-S data.

Earth Observation (EO) is taking off again in 2018 with a scheduled launch of 31 satellites next Friday, 12th January, from a single rocket by the Indian Space Research Organization (ISRO). The launch will be on the Polar Satellite Launch Vehicle (PSLV-40) from the Satish Dhawan Space Centre in Sriharikota, India. ISRO has history of multiple launches, setting the world record in February 2017 with 104 satellites in one go.

The main payload next week will be Cartosat-2F, also known as Cartosat-2ER. It is the next satellite in a cartographic constellation which focuses on land observation. It carries two instruments, a high resolution multi-spectral imager and a panchromatic camera. It’s data is intended to be used in urban and rural applications, coastal land use, regulation and utility management.

At Pixalytics we’re particularly excited about the Carbonite-2 cubesat built by Surrey Satellite Technology Ltd (SSTL) which is on this launch. .

Carbonite-2 is a prototype mission to demonstrate the ability to acquire colour video images from space. It has been developed by Earth-i and SSTL, and carries an imaging system capable of delivering images with a spatial resolution of 1 m and colour video clips with a swath width of 5 km. Earth-i have already ordered five satellites from SSTL, as the first element of a constellation that will provide colour video and still imagery for the globe enabling the moving objects such as cars, ships or aircraft to be filmed. These satellites are planned for launch in 2019.

However, this isn’t the only cubesat with an EO interest on next week’s launch. In addition, there are:

  • KAUSAT 5 (Korea Aviation University Satellite) will observe the Earth using an infrared camera and measure the amount of radiation from its Low Earth Orbit (LEO).
  • Parikshit is a student satellite project from the Manipal Institute of Technology in India that carries a thermal infrared camera, using 7.5-13.5 µm wavelengths, and will be used to monitor urban heat islands, sea surface temperature and the thermal distribution of clouds around the Indian subcontinent.
  • Landmapper-BC3, a commercial satellite from Astro Digital in the USA to provide multispectral imagery at 22 m spatial resolution with a swath width of 220 km
  • ICEYE-X1 is a SAR microsatellite from the Finnish company ICEYE which is designed to provide near real-time SAR imagery using the S-Band. ICEYE is a recent start-up company who have raised $17 m in venture capital funding in the last few years. They hope to have a global imaging constellation by the end of 2020.

Amongst the remaining cubesats, there are a couple of really intriguing ones:

  • CNUSail 1 (Chungnam National University Sail) is a solar sail experiment from Chungnam National University in South Korea. It aims to successfully deploy a solar sail in LEO and then to de-orbit using the sail membrane as a drag-sail. There has been a lot of discussion around solar sails from propulsion systems through to mechanisms to clear space debris, so it will be fascinating to see the outcome.
  • IRVINE01 is the culmination of a STEM project started in 1999 in six public high schools in Irvine, California, which has given students the experience of building, testing and launching a cubesat to inspire the next generation of space scientists. This is a fantastic project!

We’re also really excited about the launch of the NovaSAR-S cubesat, which was also originally planned to be on this launch (as reflected in the first version of this blog). It is going to be launched later this year. NovaSAR-S, also built by SSTL, is of particular interested to Pixalytics as we’ve previously been involved in a project to simulate NovaSAR-S data and so we’re excited to see what the actual data looks like. NovaSAR-S is a Synthetic Aperture Radar (SAR) mission using the S-Band, which will operate in a sun-synchronous orbit at an altitude of 580 km. It has four imaging modes:

  • ScanSAR mode with a swath width of 100 km at 20 m spatial resolution.
  • Maritime mode with a swath width of > 400 km and a spatial resolution of 6 m across the track and 13.7m along the track.
  • Stripmap mode with a swath width of 15-20 km and a spatial resolution of 6 m.
  • ScanSAR wide mode with a swath width of 140km and a spatial resolution of 30 m.

The data will be used for applications including flooding, disaster monitoring, forestry, ship tracking, oil spill, land cover use and classification, crop monitoring and ice monitoring. We’ve going to keep an eye out for its launch!

This is just the start of 2018, and we hope it’s piqued your interest in EO as it’s going to be an exciting year!

Have you read the top Pixalytics blogs of 2017?

World Cloud showing top 100 words from Pixalytics 2017 blogs

In our final blog of the year, we’re looking back at our most popular posts of the last twelve months. Have you read them all?

Of the top ten most read blogs, nine were actually written in previous years. These were:

You’ll notice that this list is dominated by our annual reviews of the number of satellites, and Earth observation satellites, orbiting the Earth. It often surprises us to see where these blogs are quoted and we’ve been included in articles on websites for Time Magazine, Fortune Magazine and the New Statesman to name a few!

So despite only being published in November this year coming in as the fourth most popular blog of the year was, unsurprisingly:

For posts published in 2017, the other nine most popular were:

2017 has been a really successful one for our website. The number of the views for the year is up by 75%, whilst the number of unique visitors has increased by 92%!

Whilst hard work, we do enjoy writing our weekly blog – although staring at a blank screen on a Wednesday morning without any idea of what we’ll publish a few hours later can be daunting!

We’re always delighted at meetings and conferences when people come up and say they read the blog. It’s nice to know that we’re read both within our community, as well as making a small contribution to informing and educating people outside the industry.

Thanks for reading this year, and we hope we can catch your eye again next year.

We’d like to wish everyone a Happy New Year, and a very successful 2018!

Merry Christmas!

UK at night. November 2017 monthly composite from the Visible Infrared Imaging Radiometer Suite,(Day/Night Band). Image and Data processing courtesy of Earth Observation Group, NOAA/NCEI.

MERRY CHRISTMAS

AND BEST WISHES FOR 2018 

from everyone at Pixalytics

Unintended Consequences of Energy Saving

Black Marble 2016: Composite global map created from data acquired by VIIRS in 2016. Image courtesy of NASA/NASA’s Earth Observatory.

Last month a report in Science Advances got a lot of publicity as it described the increase in global light pollution following research using satellite data. Even more interesting was the fact that one of the key drivers, although not the only one, was the switch to LED lights which have mainly being bought in due to their increased energy efficiency.

Recently there has been a lot of night-time imagery released as photographs taken from the International Space Station, and we’ve used them in our blogs. However, night time imagery has also been collected from the uncalibrated Operational Linescan System (OLS) on the Defense Meteorological Satellite Program (DMSP) satellites for a number of years. This was followed by the Suomi National Polar-orbiting Partnership (Suomi NPP) research mission in 2011 that carries the Visible Infrared Imaging Radiometer Suite (VIIRS) which had a planned life expectancy of around five years, however it is still in orbit and continues to collect data. Much more recently, on the 18th November 2017, a second VIIRS instrument was launched aboard the NOAA-20 satellite (previously called JPSS-1).

The role of LED lights in the increase in light pollution was described in detail in the paper ‘Artificially lit surface of Earth at night increasing in radiance and extent’ by Kyba et al which was published on the 22nd November 2017. The paper was based on satellite data collected between 2012 and 2016 from the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite and one of the key drivers behind the new research is that VIIRS offered the first calibrated and georeferenced night time radiance global dataset. Within the 22 spectral bands the instrument measures is a day/night panchromatic band (DNB). This band has a 750 m spatial resolution and operates on a whiskbroom approach with a swath of approximately 3,000 km which means it provides global coverage twice a day, visiting every location at 1:30 pm and 1:30 am (local time).

The team from the GFZ German Research Centre for Geosciences who did the research concluded that outdoor light pollution has increased by 11% over 5 years. However, for us, the really interesting part was that new LED lights are linked to this increase in light pollution.

Over the last decade within the UK, a lot of local Councils have switched to using LED streetlights mainly due to the energy, and associated cost, savings. However, there was also a message that this would reduce light pollution as they would direct light downwards and reduce nightglow. This is coupled with the fact that businesses and consumers have also been pushed to move towards this type of light for the same reasons. This was brought home to us recently as a firm opposite our home installed new outside LED lights. It has made a significant different to the amount of light in our room and even in the middle of the night it is never completely black.

What the research team found by comparing VIIRS images from 2012 and 2016 was that:

  • The lower cost of LED lights has actually led to more lights going up, mainly on the outskirts of towns and cities. A 2010 paper by Tsao et al published in Physics Today indicated that we tend to purchase as much artificial light as possible for around 0.7% of GDP and so as lighting becomes cheaper, the quantity increases.
  • Flat composite global map created from data acquired by VIIRS in 2016. Image courtesy of NASA/NASA’s Earth Observatory.

    There has been a shift in the spectra of artificial light within cities from the yellow/orange of the old streetlights to the white of LED’s.

  • The majority of countries of the world had seen an increase in light pollution. Although, perhaps surprisingly some of the world’s brightest nations such the US, UK, Germany, Netherlands, Spain and Italy had stayed stable; which may suggest there is a point of saturation of outdoor lighting. The only countries that had less light pollution were areas of conflict or whether there was issue with the data, such as Australia where there were significant wildfires when the first data was collected.

Light pollution has a negative impact on flora and fauna, particularly nocturnal wildlife, and there is increasing evidence that it is also negative for humans. This is an example of why we have to be so careful with the concept of cause and effect. Decisions made for improved energy efficiency look to have had unintended consequences for light pollution.