New space lasers offer best 3D look at global forests yet

first_imgArticle published by Sue Palminteri boreal forests, Conservation Solutions, Forests, LiDAR, Mapping, Monitoring, Remote Sensing, satellite data, Satellite Imagery, Sensors, Technology, Tropical Forests, Wildtech Forest monitoring has increasingly turned to satellites over the past several decades, and 2018 was no exception.In the last few months, NASA launched two sensors into space that will play a prominent role in monitoring forest biomass and structure over the next decade: the Global Ecosystem Dynamics Investigation (GEDI) now attached to the International Space Station, and the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2).These two satellites, which in combination provide complete coverage of the planet, are equipped with lidar sensors that record forest structure in 3D, contributing to an ongoing wave of large-scale forest ecosystem measurements. Researchers and forest managers working to record and reduce the rapid loss of forests are now armed with a new tool to monitor vegetation across the globe. In December 2018, a SpaceX rocket launched the NASA-engineered Global Ecosystem Dynamics Investigation (GEDI) sensor up to the International Space Station to gather data on the structure and extent of forests.Scientists have increasingly relied on remote sensing methods to estimate the extent of forest landscapes, in particular collecting data from space at a large scale. Over the next several years, GEDI will provide the most accurate lidar (light detection and ranging) data on tropical and temperate forests ever to be collected from space.Satellite lidar systems determine vegetation structure by emitting lasers down to Earth at a known distance from the planet’s surface and measuring the time it takes for the lasers to return to their origin. As the satellite orbits the Earth, its lasers bounce off different features of a landscape. Shorter return times correspond to taller features, such as the top of a forest canopy, while longer return times correspond to shorter features, such as grassy plains. Where elevation of an area is known, very precise heights of vegetation features can be determined across the landscape.NASA’s Global Ecosystem Dynamics Investigation (GEDI) sensor launched to the International Space Station in December 2018 offers a 3D view of temperate and tropical forests. Video by NASA Goddard Space Flight Center.The benefit of GEDI’s lidar is its ability to collect forest structure data in three dimensions, which enables scientists to not just categorize different types of land cover but also record vegetation canopy height and tree density, which other satellite sensors cannot. GEDI’s lasers will also penetrate the forest canopy to map understory growth, surveillance that no satellite to date has been able to do and would otherwise be near impossible without the difficult fieldwork of measuring forest biomass and carbon storage from the ground.Scientists agree that forests are disappearing rapidly and globally, but the speed with which the world is de-greening and how much of Earth’s carbon and biodiversity are lost along with forests are not well understood. The amount of carbon released when forests are cut down or burned depends on the amount of biomass the forests contain. Carbon emissions from deforestation play a substantial role in assessing the impact of human activity on climate.“The largest gap is that we do not know the existing carbon stocks of the Earth’s forests,” Dr. Ralph Dubayah, the principal investigator of GEDI and professor of geography at the University of Maryland, told Mongabay. “Canopy height provides a direct link to a tree’s weight because just as with humans, larger trees weigh more than younger trees. About half a tree’s biomass is carbon. So if we know the heights globally, we can make much better maps of global forest carbon.”Satellite-mounted lidar can also help scientists record how long it has been since a forest starting growing or was last cut down, also known as its successional state. Trees in old-growth forests tend to be bulkier and taller and therefore store more carbon and offer unique ecosystems that younger forests don’t.Powerful lidar sensors, such as the GEDI satellite sensor, can record layers of vegetation structure even in dense tropical rainforests. Lidar data collected by planes or satellites produces three-dimensional depictions of the vegetation below. Image courtesy of GEDI team.“Conventional satellite data can show you when a patch of forest has been lost, disturbed or degraded,” said Dubayah, “but you don’t know how much that deforestation has contributed to atmospheric CO2. The net balance between how much you lose through deforestation and how much you gain through regrowth is one of the largest uncertainties in the global carbon cycle.”Combined, satellite lidar sensors scan entire planet’s surfaceGEDI was not the only lidar sensor NASA sent to space in 2018. ICESat-2, a satellite launched in mid-September 2018, is also beaming lasers down from space as it orbits the earth at a speed of 4.3 miles per second. Although ICESat-2’s primary mission, and namesake, is monitoring polar ice caps, the lidar lasers shot from its sensor will also record elevation and structure of the vegetation, ocean, and rocky surfaces surrounding the polar regions, including those of the boreal forests. These high-latitude data would complement those of areas closer to the equator generated by GEDI, said Dr. Joe MacGregor, a NASA glaciologist on the ICESat team. “Along with ICESat-2’s polar coverage, GEDI will cover between 51° latitude North and 51° latitude South to round out the picture.”ICESat-2, a lidar satellite launched in September 2018, will complement GEDI measurements of tropical and temperature forests with its own extensive coverage of boreal forests near polar regions. Video by NASA Goddard Space Flight Center.ICESat-2 is the successor to ICESat-1, which launched in 2003 and orbited until 2010. ICESat-1, which also had a lidar sensor, enabled NASA scientists to create the first global map of an average forest canopy height for every square kilometer (0.4 square miles). The new ICESat will yield an updated global map of canopy heights that is expected to be 1,000 times higher resolution than the ICESat-1 map, and GEDI will map forest canopy metrics at an even higher resolution (a grid of 25-meter cells).The new ICESat is equipped with a particular flavor of lidar that is excellent for mapping the depth of ice sheets and the canopy height of forests, but it has difficulty penetrating the dense vegetation of tropical rainforests—the forests that GEDI is conveniently positioned to map with its vegetation-optimized lidar sensors.“We have a project looking at merging GEDI and ICESat-2 data for estimating biomass,” Dr. Laura Duncanson of NASA told Mongabay. “The two science teams are working closely together.” Duncanson said she and members of the ICESat-2 team had joined each other’s meetings and plan to continue their coordinated efforts to integrate data.Oil palm plantation in Malaysian Borneo with newly cleared hills in foreground surrounded by forest. Satellite lidar data can track when the structure of forests changes, such as when deforestation or degradation occurs, as when a natural forest supporting hundreds tree species is cleared and replanted with a monoculture such as oil palm. Image by Rhett A. Butler/Mongabay.Biomass monitoring has become increasingly important with the onset of carbon accounting programs such as REDD+ (Reducing Emissions from Deforestation and forest Degradation), which aim to provide monetary incentives to conserve forests that offset the potential value lost by not cutting down forests. Knowledge of how much carbon is stored in a given area of forest is crucial for establishing such offsetting programs, although international efforts to establish emission accountability metrics have continued to fall short of goals. Nonetheless, carbon cap-and-trade markets are growing, as are the prospects of initiating a carbon tax in some economies.Besides biomass and carbon stock measurements, this global-scale lidar data will inform other research as well. Recording canopy height and various metrics of forest complexity at large scales enables scientists to characterize different forest ecosystems. When paired with on-the-ground species distribution data, ecologists can roughly estimate the biodiversity of forests, which can help set conservation priorities. Years of satellite lidar data can also improve understanding of how forest structure changes over time due to tree growth, mortality, and competition.Building and launching satellites requires deep pockets up front but can save researchers a vast amount over time. GEDI’s budget of $94 million pales in comparison to the budgets of the Landsat-9 land monitoring satellite ($885 million) and the European Space Agency’s Copernicus mission ($4.9 billion). The low cost of GEDI is largely thanks to hitching a ride on the International Space Station and expedient progress by NASA scientists and engineers.“Conceiving and creating the technology in such a short span (four years) on this budget has been a major accomplishment,” Dubayah said. “GEDI was completed six months early and under budget, which is nearly unheard of.”Overhead view of a diverse rainforest in Peru’s Amazon. Image by Rhett A. Butler/Mongabay.A new hope for forests?Although both the GEDI and ICESat-2 lidar sensors will likely last only until 2021 and 2022, respectively, researchers and land managers use the data from ecosystem satellites for many years: ICESat-1 maps are still contributing to conservation science 10 years after the satellite was decommissioned. As the costs of large-scale, high-resolution forest monitoring decrease, so does the availability of data and tools to track land cover change at incredibly fine scales.These two lidar sensors complement the fine-scale (5-meter, or 16.5-foot) synthetic aperture radar (SAR) satellites already in orbit, and the next decade will likely witness the launch of NISAR, a joint initiative between the United States and India, and the European Space Agency’s BIOMASS mission, both of which are assigned to record global environmental changes.In a galaxy far, far away, Jedi see through others with the Force. Starting this year above our own planet, GEDI can now see through the forest. According to Dubayah, the dramatic advances being made in remote sensing technologies will improve scientists’ ability to measure– and therefore better protect– the extent and structure of global forests.“We are entering a new era of ecosystem observation where we can finally get at canopy 3D structure,” he said, “a very exciting development indeed.”CitationNeuenschwander, A., & Pitts, K. (2019). The ATL08 land and vegetation product for the ICESat-2 Mission. Remote Sensing of Environment, 221, 247-259. Use this form to send a message to the editor of this post. If you want to post a public comment, you can do that at the bottom of the page.center_img Popular in the CommunitySponsoredSponsoredOrangutan found tortured and decapitated prompts Indonesia probeEMGIES17 Jan, 2018We will never know the full extent of what this poor Orangutan went through before he died, the same must be done to this evil perpetrator(s) they don’t deserve the air that they breathe this has truly upset me and I wonder for the future for these wonderful creatures. So called ‘Mankind’ has a lot to answer for we are the only ones ruining this world I prefer animals to humans any day of the week.What makes community ecotourism succeed? In Madagascar, location, location, locationScissors1dOther countries should also learn and try to incorporateWhy you should care about the current wave of mass extinctions (commentary)Processor1 DecAfter all, there is no infinite anything in the whole galaxy!Infinite stupidity, right here on earth.The wildlife trade threatens people and animals alike (commentary)Anchor3dUnfortunately I feel The Chinese have no compassion for any living animal. They are a cruel country that as we knowneatbeverything that moves and do not humanily kill these poor animals and insects. They have no health and safety on their markets and they then contract these diseases. Maybe its karma maybe they should look at the way they live and stop using animals for all there so called remedies. DisgustingConservationists welcome China’s wildlife trade banThobolo27 JanChina has consistently been the worlds worst, “ Face of Evil “ in regards our planets flora and fauna survival. In some ways, this is nature trying to fight back. This ban is great, but the rest of the world just cannot allow it to be temporary, because history has demonstrated that once this coronavirus passes, they will in all likelihood, simply revert to been the planets worst Ecco Terrorists. Let’s simply not allow this to happen! How and why they have been able to degrade this planets iconic species, rape the planets rivers, oceans and forests, with apparent impunity, is just mind boggling! Please no more.Probing rural poachers in Africa: Why do they poach?Carrot3dOne day I feel like animals will be more scarce, and I agree with one of my friends, they said that poaching will take over the world, but I also hope notUpset about Amazon fires last year? Focus on deforestation this year (commentary)Bullhorn4dLies and more leisSponsoredSponsoredCoke is again the biggest culprit behind plastic waste in the PhilippinesGrapes7 NovOnce again the article blames companies for the actions of individuals. It is individuals that buy these products, it is individuals that dispose of them improperly. If we want to change it, we have to change, not just create bad guys to blame.Brazilian response to Bolsonaro policies and Amazon fires growsCar4 SepThank you for this excellent report. I feel overwhelmed by the ecocidal intent of the Bolsonaro government in the name of ‘developing’ their ‘God-given’ resources.U.S. allocates first of $30M in grants for forest conservation in SumatraPlanet4dcarrot hella thick ;)Melting Arctic sea ice may be altering winds, weather at equator: studyleftylarry30 JanThe Arctic sea ice seems to be recovering this winter as per the last 10-12 years, good news.Malaysia has the world’s highest deforestation rate, reveals Google forest mapBone27 Sep, 2018Who you’re trying to fool with selective data revelation?You can’t hide the truth if you show historical deforestation for all countries, especially in Europe from 1800s to this day. WorldBank has a good wholesome data on this.Mass tree planting along India’s Cauvery River has scientists worriedSurendra Nekkanti23 JanHi Mongabay. Good effort trying to be objective in this article. I would like to give a constructive feedback which could help in clearing things up.1. It is mentioned that planting trees in village common lands will have negative affects socially and ecologically. There is no need to even have to agree or disagree with it, because, you also mentioned the fact that Cauvery Calling aims to plant trees only in the private lands of the farmers. So, plantation in the common lands doesn’t come into the picture.2.I don’t see that the ecologists are totally against this project, but just they they have some concerns, mainly in terms of what species of trees will be planted. And because there was no direct communication between the ecologists and Isha Foundation, it was not possible for them to address the concerns. As you seem to have spoken with an Isha spokesperson, if you could connect the concerned parties, it would be great, because I see that the ecologists are genuinely interested in making sure things are done the right way.May we all come together and make things happen.Rare Amazon bush dogs caught on camera in BoliviaCarrot1 Feba very good iniciative to be fallowed by the ranchers all overSponsoredlast_img

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