UCL Geography Blog
Investigating fish passage through the VETT hydropower system: UCL Geography industry collaboration
Guest post by Jennifer Gomez Molina, VerdErg Renewable Energy Ltd
Renewable Energy is big business nowadays. With the UK legally committed to the 2009 Renewable Energy Directive target to achieve 15% of its energy consumption from renewable sources by 2020, there is a major drive to get non-fossil fuel power sources up and running. In addition to addressing energy security and climate change, it is important to ensure that their installation and operation is environmentally considerate. For hydropower, concern has been raised about the increased hydrodynamic activity in aquatic environments and the consequent impacts on inter-linking ecosystems. Prime concerns are the impact on fish passage through these systems and the impact of these renewable energy devices on fish migration. There are various initiatives by environmental stakeholders and conservation groups to promote fish migration by decommissioning weirs but these weirs are ideal locations for hydropower generation. Can we find a balance between conservation and generating economic green energy?
I joined UCL in 2011 during my sabbatical from industry to do a Masters in Aquatic Science. Working in hydropower R&D, I wanted to advance my skills in aquatic ecosystems, environmental assessment techniques and conservation which my employer VerdErg Renewable Energy Ltd actively supported by funding my postgraduate degree and giving me the opportunity to collaborate with them for my thesis. Using VerdErg’s Venturi-Enhanced Turbine Technology (VETT) as a case study, we developed a MATLAB model with programmed safe hydrodynamic pressure boundaries from literature to determine specific design configurations and hydrodynamic conditions that would be safe for juvenile fish passage. VETT is designed to amplify low head hydropower sources by as much as five times so a conventional small, high speed turbine and generating equipment can be installed economically. 80% of the flow is passed through a primary circuit and venturi, creating region of low static pressure which draws the remaining flow via a turbine at an amplified head drop. The turbine, which takes 20% of the flow, will always be screened. The research outcomes proved invaluable and gave hope to the fact that hydropower can accommodate the conservation needs of vulnerable species and promote fish survival.
Schematic of VerdErg’s Venturi-Enhanced Turbine Technology (VETT)
After a month off to visit my family in Colombia (epic R&R required post thesis submission), it was back to work for me. The outcome of my research was inspiring, the next step was to acquire hard evidence; we all know “the proof is in the pudding”. VerdErg gave me the task to create and manage a testing programme to test live fish through a full scale instrumented prototype and determine their survivability with special focus given to juvenile fish due to their vulnerability to extreme hydrodynamic conditions in hydropower systems. The research for my thesis enabled me to identify key environmental and engineering test parameters such as which fish species to assess and under what operating conditions. In addition, my literature review identified the key concerns for fish migration and hydropower enabling me to liaise with the Environment Agency about how these could be addressed through this work.
In May 2013, we conducted the live trials in collaboration with Vis Advies BV at their facility in Nieuwegein, The Netherlands. The testing programme focussed on the hydrodynamic conditions that fish would experience when passing through the VETT’s primary circuit and venturi. This essentially would replicate what was modelled in the MATLAB model.
Jennifer Gomez Molina during installation of the VETT system (left), and conducting live trials (right)
In total, 827 fish were tested comprising of European eel, Atlantic salmon, Rainbow trout and Round goby. Using the “forced exposure method” developed by Vis et al., 2011, these fish were tested at 1.0m, 1.5m and 2.0m head drop with a maximum flow rate of 450 l/s. Independent Third Party Verification was conducted by Dr Billy Sinclair from at University of Cumbria which was funded by the Technology Strategy Board Innovation Voucher scheme.
Jennifer conducting weight and length measurements of test and control fish to determine their survivability through the full scale instrumented VETT prototype
No immediate or latent mortality or internal or external injuries from passage were observed for all test scenarios, rating the VETT model a maximum score of 1 with classification “Outstanding”. As the VETT is scalable, these findings can be extrapolated to tidal and river sites with the same hydrodynamic profiles.
A smolt in the culvert trying to swim upstream after passing through the venturi, demonstrating that fish can survive passage through the VETT system
These research outcomes inform key concerns with fish migration especially of salmonids and eels and have relevance to the efforts to restore their populations. In addition, they support the nation’s green energy goals to ensure renewable energy is environmentally considerate. VerdErg hopes to follow up this milestone achievement with a long term fish testing programme as may be required to address specific future project issues. You can find out more about the Venturi-Enhanced Turbine Technology and this project on VerdErg’s website and .
I am grateful for the lessons learnt from my taught courses at UCL which enabled me to apply my acquired knowledge to real life innovative work. For me now, it is back to saving the world, one VETT at a time.
Jennifer Gomez Molina works as an Environmental Analyst for VerdErg Renewable Energy. She completed the UCL Geography MSc Aquatic Science course in 2012 and continues to have links with the department.
I found these maps and thought they would carry on the Gabon theme for this month. They are a series of economic maps of the French Equatorial Africa from 1956 both at 1:5000000 scale and published by Service Geographique de l'A.E.F. French Equatorial Africa was established as a federation in 1910 and was made up from countries including Gabon, Chad, Middle Congo (now People's Republic of the Congo), and Ubangi-Shari (now Central African Republic). Independence came in 1960.
UCL Geography researchers at 11th International Ecology Association Congress
by Luca Marazzi, Arnaud Duranel and Emily Lines
We all know how wide-ranging Geography topics are in our Department, with the long-standing division between Physical and Human Geography, and within each field, e.g. Ecology and Palaeoecology, Climatology and Palaeoceanography, Urban studies and Migration studies, and so on. Considering ourselves both biogeographers and ecologists, we were excited to attend the INTECOL Congress “Ecology: Into the next 100 years” held here in London on 18-23 August, involving over 2,500 scientist from 67 countries and coinciding with the Centenary of the British Ecological Society.
23 oral sessions, 43 symposia, 38 workshops and 11 plenary lectures took place on a vast range of topics, including biodiversity, ecosystem services, climate change, conservation, biogeography, evolution, but also parasites, light pollution and urban ecosystems, among others (see full programme). The Congress was overwhelming, loaded with inspiring science, discussions and networking opportunities. The global community of Ecologists was well represented (although it would have been good to see more participants from developing nations), and it was brilliant to meet and speak with top scientists such as Robert May (author of Stability and Complexity in Model Ecosystems and former Chief Scientific Adviser to the UK Government), Simon Levin (author of Ecosystems and the Biosphere as Complex Adaptive Systems), Steve Hubbell (author of The Unified Neutral Theory of Biodiversity and Biogeography), Ilkka Hanski (who helped develop the Metapopulation Theory) and David Tilman (who conducted crucial research on resource competition and biodiversity).
Luca Marazzi with Professor Lord May of Oxford (Former Chief Scientific Adviser to the UK government and mathematical ecology legend) and Karolina Petrovic, Charles Sturt University (Australia).
In the Aquatic Ecology session, Luca Marazzi gave a well-attended oral presentation of his PhD research about the 495 species of algae he observed in over 130 samples from the Okavango Delta (Botswana). In this wetland, the algal biomass and diversity are influenced by annual flood-pulse, habitat diversity and key environmental variables such as conductivity and nutrient concentrations.
UCL Geography’s Arnaud Duranel, who presented a poster on his work on the eco-hydrology of acidic mires in Central France, said the Congress was humbling due to the high quality of speakers and the range of pressing issues discussed. He explains that it was alarming to hear about the current rate of climate change (higher than during any of the preceding mass extinctions), and listen to a former US chief scientist’s story of his fruitless attempts at engaging debate with decision-making republican congressmen dismissing centuries of scientific progress on religious grounds. However, there is hope; Arnaud’s highlights were the two resolutely positive plenary talks by Bill Sutherland and David Tilman and the following debates. “It was inspiring to hear a highly recognised expert such as David Tilman arguing that it was possible to reconcile food production for 9 billion people and biodiversity conservation, and that preserving biodiversity would actually help with the former”.
Emily Lines presented her post-doc work on remote sensing of vegetation using satellite data and the impact of canopy structural heterogeneity on optical reflectance. Many vegetation ecologists are using more and more remote sensing data such as optical reflectance, LIDAR and radar, and her poster generated lots of interesting discussions about ecological applications of these types of data. The recent trend of increasing interest in advanced computational and mathematical methods in ecology continued within the conference sessions, and there were very well attended workshops on building better code and managing large data.
In a workshop on how to secure funding, senior scientists advised Ph.D. students and other scholars on how to make the most of networking opportunities, find the right grant and be resilient versus failures. Personal stories were uplifting, but a Zoology Professor admitted that “these days you would not get a post-doc without having published papers from your thesis” like he did some time ago. Competition for research posts has massively increased, but funding provision is not keeping pace with demand. Robert May had some good advice for aspiring scientists: to pick a solvable problem, surround yourself with good people and be lucky!
Luca’s thoughts during the Congress went to its slogan “Advancing ecology and making it count”. What about enhancing the lobbying power of ecologists for the sake of humanity and planet Earth? Why not ask the government and other players more vocally to better fund basic and applied research in order to understand and solve the very problems that we study with our brains, but we have at heart, such as climate change, species loss and food insecurity?
In this respect, one thing that we would really like to see in future Ecology conferences is more media presence and laypeople. What about having open days for the general public in which “normal” (especially young) people are invited in the audience? Yes, there are increasing public engagement activities and citizen science all over the world, but the issues discussed at INTECOL are so important for humanity that having (more) policy makers, stakeholders, journalists and members of the public could constitute a valid experiment. We will see. There are eminent scientists like Ecologist Paul Ehrlich who, in the face of a possible climate catastrophe, even suggested the formation of a “popular movement based in academia and civil society to help guide humanity towards developing a new multiple intelligence, “foresight intelligence” to provide the long term analysis and planning that markets cannot supply”.
Beliefs and practices are changing. In her Presidential address, Georgina Mace, Director of the new UCL Centre for Biodiversity and Environment research, highlighted how attitudes towards “what nature conservation is for” changed over the decades, from “Nature for itself” to today’s “People and Nature” via “Nature despite People” and “Nature for People”. Encouragingly, alliances between scientists and the public for “Nature and People” do take place and hopefully policies will increasingly follow evidence-based societal demands for sustainability.
Professor Boije Fu presenting the Ecological Society of China’s gift plaque to BES President Professor Georgina Mace for the BES Centenary.
In four years’ time much will have happened to the Earth and its inhabitants. Ecologists will meet at the 12th INTECOL Congress “Ecology and civilization in a changing world”, hosted in Beijing by the Ecological Society of China (20-25 August 2017). Before then the next Ecosummit in 2016 and the Joint Annual Meeting of the British Ecological Society & Société Française d'Ecologie (December 2014) will happen in France. There is a lot to look forward to in the rest of the century for Ecologists, Physical and Human Geographers and academics at large, especially in an era when, hopefully, disciplinary barriers will be overcome to solve the severe social and environmental challenges we face.
Luca Marazzi is a part-time PhD candidate at UCL Geography studying the ecology of algae in the Okavango Delta, key primary producers in the food webs of this unique subtropical wetland. More details can be found .
Arnaud Duranel is a PhD candidate at UCL Geography studying peatlands in central France, with a particular interest in their hydrology and vegetation ecology.
Emily Lines is a Postdoctoral Research Associate at UCL Geography interested in Remote Sensing of vegetation and forest ecology. More details can be found here.
By Andrew Burt
Following on from Mat Disney’s previous post Shining a light on forest structure I have recently returned from a three and a half week field campaign in Gabon, West Africa to continue researching the potential of terrestrial laser scanning for quantifying forest structure.
Our main aim was to take a laser scanner into a tropical forest environment for the very first time and survey regularly monitored plots that form part of the Global Ecosystem Monitoring network. Here, a host of direct field measurements, including trunk diameter and height, are rigorously collected for each individual tree in a one hectare plot to identify forest state and dynamics. Destructive harvesting is used to understand how tree trunk diameter and height relate to tree biomass.
Research combining terrestrial laser scanning and 3D modelling work undertaken at UCL Geography (see here) and colleagues from Tampere University of Technology (see ) has allowed us to estimate forest biomass in a fashion that is completely independent of these direct field measurements. Laser scanning produces a full spatial representation of the scanned area in the form of a 3D point cloud as shown in the video and images below. By converting these point clouds into a topological description of tree structure we can derive volume and hence biomass. This methodology provides a wealth of further benefits as these 3D tree models can also be used to drive remote sensing models for instrument analysis and parameter retrieval algorithms. Collaboration with UCL Geography forest ecologist Simon Lewis is providing the opportunity for these models to answer fundamental ecological questions which are difficult to assess using traditional measurement techniques.
A fly-through of some of the 3D data from Lope National Park (video: Kim Calders)
An individual tree extracted from the point cloud (left) and the 3D model of this isolated tree (right). Data acquired at Brisbane Forest Park, Australia (image: Andrew Burt)
Applying this approach in Gabon at regularly monitored plots is a great way to compare the output of direct field measurements and remote sensing efforts. Through this, we can investigate their agreement and/or disagreement and ultimately improve how we go about measuring forest structure.
Accompanied by two colleagues, Kim Calders and Jose Gonzalez de Tanago Menaca from the Laboratory of Geo-information Science and Remote Sensing at Wageningen University and their RIEGL VZ-400 terrestrial laser scanner we arrived into the capital, Libreville, prior to heading out to the first site in Akandah National Park. In just seven days and battling with some extensive understory and a multitude of very large ants, we managed to survey two, one hectare plots.
Akandah National Park (image: Jose Gonzalez de Tanago Menaca)
Following this we journeyed to Lope National Park located in the centre of the country which is a wonderful mix of savannah through to old growth forest. Here we scanned one further plot and ten smaller monitored plots that covered the full range of forest types present at Lope.
The team in front of a 2.5m diameter tree in Lope National Park (image: Jose Gonzalez de Tanago Menaca)
It was here that we also came across a friendly elephant known to the locals as Billy who kindly allowed us to give him a quick scan!
Billy the elephant! (image: Kim Calders)
This short campaign was a huge success and has demonstrated the feasibility of using laser technology to monitor forest structure in harsh conditions. Work is now underway to analyse the 210GB of scanner data acquired and we hope for there to be more news on this soon!
by Simon Turner
“A couple of metres from the mangrove edge, I spot in the corner of my eye a large shape rising out of the water. I scream, in a manly way, to assure my machete wielding assistant that I am clearly not afraid of crocodiles and have only up-ended a sunken tree branch with my makeshift raft...”
Following a successful application for funding from The Leverhulme Trust, I and colleagues from UCL Archaeology went to our research site in Ambergris Caye, Belize. We are investigating the landscape scale effects of long term human activity over the last 1000 years in coastal Belize. The site (named Marco Gonzalez) supported occupation and activity since Preclassic Maya times (ca. 300 B.C. and probably earlier). Although activities fluctuated in kind and in intensity over time, there is no evidence at Marco Gonzalez of the collapse that depopulated a number of mainland sites between ca. A.D. 750 and 1000. Instead, far-flung trade and exchange activity flourished during this period and set the stage for the seaborne commerce which so impressed Spanish conquerors in the 16th century.
The field site from the air, approaching Ambergris Caye, Belize. The site is marked by a difference in vegetation. Note azure coral sea and barrier reef in background and scatter of mosquito friendly pools.
Prior to collapse, during the Late Classic period between ca. A.D. 550 and 750, when mainland cities such as Tikal reached the height of their power, inhabitants of Marco Gonzalez were producing salt on an apparently large scale. They cleared vegetation, collected salt, and, as a final step, heated brine in ceramic vessels in order to drive off water, which resulted in deposition of pyrogenic carbon—presumably the remains of the fuel used in heating the brine. When salt production ceased, sometime between about A.D. 750 and 800, buildings of local reef-stone and wood were constructed over salt production sites, settlement expanded, and people were buried (as is Maya practice) beneath the floors of successive structures. About A.D. 1200-1250, inhabitants drifted away from the area, although a few families continued to live at Marco Gonzalez until the 16th century. The decision to abandon the site was likely to have been also influenced by changes in coastal evolution that led to back barrier sedimentation and mangrove expansion.
Of key interest at Marco Gonzalez are the dark soils, or anthropogenic black earths, that developed during occupation of the site. Pyrogenic carbon comprising the salt processing debris is thought to play a pivotal role in dark earth formation. The site consists of large mounds of dark soil and waste products from the processing of marine resources, underlying, covering and forming the core of structures related to the phases of Maya occupation. The anthropogenic soils and processing materials also spread out from the site and mixed with the coastal and mangrove sediments as they in-filled the back barrier lagoon.
Core retrieved from the mangrove margin at Marco Gonzalez. The dark brown mangrove peat (left) sits on top of lagoon mud and artefact detritus from the site. Is this core recording the end of occupation at the site when the mangroves blocked access to the open sea? We will have to wait and see once all the analyses have been completed.
My role in the project is to investigate how the soils and archaeological stratigraphy found at the site relate to the coastal wetland and lagoon sediments found around the periphery of the occupied area. The multidisciplinary and cross-departmental (Archaeology and Geography) project will run for the next 18 months analysing the sediments and soils we retrieved.
“With the core tube well and truly stuck in the mud, and not visible beneath the surface of the milky tea coloured water, the pond around me has started to writhe with fish, with some of them hitting the underside of my raft. Something brushes my arm. Screaming, in a manly fashion, happens again…”
Hitting the headlines in the San Pedro Sun (apologies for neckerchief):
Simon Turner is a Research Fellow at UCL Geography.
By Chris Brierley
During my first year at UCL, I was invited to join the editorial board of a new journal that was being established. I must confess I was pretty pleased to be invited, but wasn’t sure what it would entail. This journal was to be an open-access one. I knew that there are some predatory publishers out there, who aim to con unsuspecting scientists into paying a publishing fee and then making off with the money. So I checked whether this publisher was on Beall’s List and rang them to speak to the staff in Switzerland. I also knew of a couple of members of the Editorial Board, so joined in September 2012.
Apart from a nice Christmas eCard, the next I heard was when the first issue was published in June 2013. (I don’t think this this is exceptional, as they didn’t want to bother me unduly). There had been a fair bit of discussion amongst my colleagues and the media about the recent prolonged colder weather, so I was pleased to see an article tilted “On the present halting of global warming” in the first issue. Upon reading it though, I was shocked to see that it not only disputed the role of anthropogenic CO2 emissions in climate, but also failed to test any of its hypotheses. I would have rejected it if it had come to me as an editor (possibly without imposing on the good will of my peers to review it). I decided to resign immediately to show my disapproval of the lack of scientific rigour.
After further investigations, it appears that the paper was submitted by the founder of the Institute where the Editor-in-Chief works. My first hit when Googling for the author and the keyword “climate” was a debunking of the author’s earlier work on Skeptical Science. Not only did that earlier work seem suspiciously similar, but none of the criticisms of it had been addressed in this new paper. I have since been told that three peer-reviews were received for the paper and that they were supportive.
Normally, resigning would be a sufficient step to make a statement about the quality of a paper and I could stop there. Yet climate is a rather emotive topic and the blogosphere readily jumps on “science” disputing humans’ role in global warming. I have therefore posted an open resignation letter, discussing the poor quality of the science in the paper, on the Skeptical Science website (which collates and debunks arguments for why climate change is not important). It seems that the publishers have been a little taken aback and have solicited formal comments - to be published in the journal alongside the article. (Functionally the paper argued that CO2 concentrations have risen quadratically, whilst the temperatures have risen linearly. In fact CO2 concentrations rose exponentially and climate responds to the logarithm of CO2 - the logarithm of an exponential is linear.)
This whole saga has ended up taking up a lot time. I could have avoided it all if I hadn’t let the flattery of the invitation influence me. This has reiterated to me that a paper is only good science if you (or preferably the community as a whole) judge it to be good science. Peer-review is not stringent arbiter of quality science - rather it is a sieve. It relies upon the goodwill and attentive efforts of volunteers, who sometimes have bad days and the dregs can slip through.
By Sam Halvorsen
When I started my PhD on the geographies of activism and social movements back in 2011 I was welcomed into a department that had little tradition in my area of interest. Not only has the department made me feel at home with my research, but it has enthusiastically embraced my methodology of (con)fusing activism with scholarship. At the same time, UCL Geography is increasingly becoming an important space within broader networks of participatory geographers. Before discussing some of the initiatives taking place at UCL, let me briefly introduce my research and methodology.
I initially started my PhD to investigate the emerging geographies of anti-cuts movements in austerity Britain. New social movements were developing and seemed to be moving away from the dominant model of creating global networks to confront and replace neoliberal globalisation towards a newfound emphasis on place-based activism. Soon after starting, however, the Occupy movement suddenly appeared outside St Paul's Cathedral in London (and in dozens of cities worldwide), taking space in order to practice already existing alternatives to capitalist crises. I went down on Day 1 and spent most of the following months with Occupy London.
Beyond my theoretical interest in the geographies of Occupy, which soon turned to a focus on territoriality, my positionality as someone who engages in the movement first as a committed activist, and later as a researcher, led me to take seriously the potentialities of a participatory and militant research. The practice of militant research has a long and rich history of activist-researchers who are committed to social change and seek to dissolve the boundaries between theory and practice. Inherently challenging, this methodology presents opportunities to re-imagine research as a weapon, and to move away from the idea of the university as a detached space of objective research.
During the initial months of my PhD I spent most of my time with activists, in meetings and actions, and helping the Occupy movement develop. My research was from the beginning both participatory and engaging beyond the academy. Along with other militant researchers I helped set up the Occupy Research Collective as a means of countering the dominance of institutions (such as the university) in researching Occupy. It also allowed me to explore the ethics of my research in a non-institutional setting, an urgent task given that the UCL ethical committee was placing significant barriers around my study (with particular concerns over my potential involvement in illegal behaviour). It was at this stage that I had one of my first experiences of feeling that my (militant) research had an important role in our department, which came through the understanding and helpful advice from my supervisor, Alan Ingram, who helped me navigate this hurdle.
Occupy Research Collective
It was around this time, half way into my first year, that I started to become aware of the existence of spaces for participatory research in the department. Participatory research has become a banner for an eclectic range of research methodologies across diverse disciplines. Geography has taken on a leading role pushing forward participatory practices, everything from including the voices of traditionally marginalised groups directly into the research process (e.g. Participatory Action Researchers), to developing technologies that democratise data-collection (e.g. video or photo), to the sort of militant research I have described here. Browsing the department's website, being taught by its staff, or connected to its research groups, participatory methodologies are not usually something that stand out. Having searched a little harder, and been involved in a few new initiatives, I'm glad to say that this approach to the discipline is alive and kicking at UCL.
First and foremost, there are the various staff and PhD students that are already involved in participatory research of their own. Much of this is linked to existing spaces such as the interdisciplinary Urban Lab and the PhD-led Stadtkolloquium, both of which hold regular seminars that often involve a participatory theme. In the second year of my PhD, I also had the pleasure of being involved in a module that was taught by Pushpa Arabindoo entitled Urban Practices, which put participatory methodologies at the heart of both its teaching and outputs. Moreover, through my engagement with undergraduates via tutorials, I have become aware of a growing interest in participatory and militant research methodologies.
Participatory Methodologies at UCL
During the past year I have also had the fortune of working with fellow PhD students, such as Myfanwy Taylor and Pooya Ghoddousi, who have been working towards the creation of more spaces for participatory geographies at UCL. In many ways this is not only about a research methodology, but a sense of commitment to open, democratic and campaigning methods in our daily lives as researches at UCL. Following the announcement that our university had decided to try and build a new mega-campus on the location of a vibrant working-class estate in east London (a plan that has since been scrapped) some of us got together and created the Participatory, Activist and Research Network, with the aim of being more able to intervene within our department and university, but also in order to create a network of mutual-aid and support amongst PhD students (and staff), entering an increasingly precarious and neoliberalised university market.
Researchers and activists protesting at UCL over proposed campus
Over time, some of us have become more integrated with already existing participatory networks, the most notable of which is the Participatory Geographies Research Group of the Royal Geographic Society. Indeed, this year UCL hosted group's annual open space "Fuller Geographies". Perhaps of most significance is the department's decision to host a series of lunchtime seminars this year on the theme of participatory geographies, placing it at the centre of our research community. Confirmed speakers so far include J and Gavin Brown.
This tide of participatory and militant research has already swept across departments around the country, such as QMUL and Leeds. For those of us engaged in it at UCL it has thus been a welcome development to see it grow at home, and I thank the department not only for their generosity in hosting my militant research, but embracing this growing tradition of radical geography.
Sam Halvorsen is a PhD candidate at UCL Geography investigating territorial practices and territoriality in the Occupy London movement. He is funded by the Economic and Social Research Council. More details on his research can be found here: http://www.geog.ucl.ac.uk/about-the-department/people/research-students/sam-halvorsen
For August I have found a random Mexican Agriculture map that I came across while looking for some Central American maps for one of our academic staff. The map shows Soil Potential of the Tlaxcala region at 1:10,000. The village in the centre of the map is San José Atoyatenco which is 100km South East of Mexico City, it has now grown to be a large town. San José Atoyatencois is over shadowed by the archaeological site of Xochitecatl located on a dominant summit of an extinct volcano (just south of town). The map was produced in July 1944.
by Mat Disney
One of my main research interests is how we can use remote sensing to measure and understand the state and dynamics of vegetation, particularly forests. By measuring different wavelengths of reflected sunlight e.g. from satellites we can tell a lot about vegetation properties: how much there is (sort of), the rate at which it is photosynthesising and taking up carbon, how it responds to stress or disturbance, and how it is responding to climate and anthropogenic changes.
One of the big difficulties we face is that remote sensing is just that, remote; we never get to measure exactly what we want to and so we have to try and infer it from reflected radiation. This is tricky because the signal we measure is a function not only of the vegetation colour (pigments, water content) but also to its structure i.e. how much vegetation there is, and how it is arranged. This is illustrated below in an image I took using my iphone from a light aircraft window over a rainforest in Australia. The variation in greenness is clear, but so is the variation in ‘lumpiness’ (structure) and density.
A temperate rainforest on Fraser Island, Queensland, Australia (image: M. Disney).
Forest structure encapsulates the biomass of the canopy i.e. how much carbon is stored in the tree, as well as how the leaves and branches are arranged. Current estimates of forest biomass are made using field surveys of tree diameter. This is near-direct, but is labour-intensive and can only cover small areas. Remote sensing potentially provides wide coverage, at the cost of directness. A new technique for measuring tree structure has developed over the last few years, using lidar, or light detection and ranging. Lidar measures the time it takes a laser pulse fired from the instrument to hit something in the canopy and return to the detector, allowing us to build up a 3D point cloud of laser ‘hits’ over the canopy. Lidars have been mounted on aircraft to measure canopy height and structure from above. However there is increasing interest in ground-based instruments, largely developed for surveying where there is a requirement for very precise 3D measurements. Collaborations between academia and industry have resulted in new instruments that have multiple wavelengths, allowing simultaneous measurements of canopy biochemical and structural properties. At UCL Geography we have developed highly-detailed 3D modelling methods, adapted from computer graphics, to understand how these measurements might be exploited (details here). We’re now using these models, along with various colleagues in the UK, Australia, Finland and the US (e.g. see here).
A Eucalyptus tree (left), captured in 3D by the lidar scanner (centre) with the colours showing height above the ground (blue, low to red, high), and then (right) reconstructed into cylinders, allowing us to estimate volume, height and biomass. Manual measurements of the trunk diameter and height were 0.59m and 24m respectively, while the lidar-derived estimates were 0.55m and 23.9m (images: Andy Burt).
I was fortunate enough to spend Oct-Dec 2012 working with colleagues in Brisbane, Queensland to try out some of our new models and methods in collaboration with Dr. John Armston of DSITIA in Brisbane, and UCL Geography MSc Remote Sensing graduate Kim Calders (now a PhD student at Wageningen). As part of this work, I travelled with Andy Burt, a NERC-funded UCL Geography PhD student, to Brisbane at the start of August to participate in a unique experiment to test new lidar instruments for measuring forest structure. The experiment was organised by John (along with colleagues from DSITIA and UQ) and in collaboration with Terrestrial Laser International Interest Group (TLSIIG), a loose coalition of researchers interested in canopy lidar. The experiment brought together researchers from the UK, US and Australia to deploy five different lidar instruments with different capabilities at the same sites, allowing us to compare how each instrument sees the canopy structure. The only two dual-wavelength systems in the world (SALCA, developed by Prof. Mark Danson at the University of Salford, and DWEL, developed by Prof. Alan Strahler at Boston University and colleagues at CSIRO, U Mass Boston and U Mass Lowell) were joined by other, commercially-developed instruments scanning at single wavelengths, but more rapidly and some with finer detail.
The participants of the Brisbane laser scanner experiment July/August 2013, standing behind more than $1M worth of various laser scanners!
Despite logistical challenges, the odd snake sighting, a few cuts and bruises, and with some lovely midwinter weather (“only” 20 C), the experiment was a resounding success. Discussions between the teams were very productive and we are already following up on how to use the data to provide new forest measurements. We were also visited in the field by Australian ABC TV news team to record a feature on the experiment (watch here). This unique experiment is the starting point to show how lidar can be used to complement measurements from satellite and those made using field surveys. We can also use the data to derive 3D tree models that we are using to explore ecological scaling laws describing how trees grow. These measurements have only ever been possible via destructive harvesting before.
As part of the next phase of this work, Andy, along with Kim and other colleagues from UCL and Wageningen, are in Gabon, West Africa, scanning tropical forest plots with lidar. More on this in a future post, when they return!
Left: Mat Disney and Dr. Rachel Gaulton (Newcastle University) measuring bark properties for use in 3D models of the trees which are being produced from the lidar measurements (image: M. Disney).
Right: UCL Geography PhD student Andy Burt scanning a forest plot at Karawatha Forest Park, using the Riegl VZ-400 lidar instrument belonging to Dr. John Armston and DSITIA Queensland (image: M. Disney).
Many thanks to John Armston for his hard work in organising the Brisbane field experiment – without him it would not have happened. Travel funds for Mat and Andy came in part from the NERC National Centre for Earth Observation and Andy’s NERC CASE studentship (with Infoterra/Astrium GEO-Information Services Division). We are also grateful for the support for this experiment of DSITIA, Queensland, the Terrestrial Ecosystem Research Network for use of site infrastructure, and the other members of the TLSIIG team.
by Anna Plyushteva
I came to Bulgaria to do fieldwork on urban commuting. Since April 2013, I have been looking at big new transport infrastructure – represented by the recently opened Line 2 of the Sofia Metro – from within the small, familiar practices of everyday travel. What better, my reasoning went, than a socio-technical disruption such as a new metro line, to illuminate the world of the mundane and the taken-for-granted? Well, disruption is exactly what I got, but of a somewhat different kind: Bulgarians decided to bring down their government.
The peaceful protests began in mid-June, when the newly elected coalition government appointed as Head of National Security a hugely controversial figure (opinions on the street are in the rather narrow range between “mafia boss” and “mafia pawn”). I cannot do justice to the political reasons and outcomes of the unrest in this text; suffice to say that even though the appointment was withdrawn, public discontent grew. Every morning and evening, for over a month now, protesters have gathered in central Sofia. The demands are about transparency and accountability, targeted at a political establishment which has become synonymous with serving specific economic interests, including blatantly criminal ones. And for over a month, everyday travel in Sofia has been anything but mundane.
As I am writing this, sitting on a kerb during the second full-day blockade of Parliament, another evening of very unusual journeys home is descending upon the city. Key roads are shut off by protesters and police. The metro station which I had listed in my notes as the busiest station for evening commuters entering the system, is now known for being the destination for the thousands joining the protests after work. The new real-time bus stop displays blink improbable waiting times, as buses sit stranded far outside the city centre. Suddenly, the everyday journeys of my respondents begin and end in the most unexpected of places, at very unusual times.
This could have been a very frustrating fieldwork situation to deal with, so I have thought up arguments to help me fight off the visions of PhD disaster. It helps that, on a personal level, I support the cause of the protesters, and am myself one of them. But even from a PhD perspective, there are reasons to appreciate what is happening.
Firstly, the “disruption” of “normality” has highlighted the fact that my account of everyday life practices should be more about on-going process of making and reconfiguring, and less about perpetual repetition of whatever I happen to frame as the “typical day”. The reason may be a new metro station, a headache, a new watch, or indeed civil unrest: in all cases, daily urban mobilities involve the continuous shaping of the everyday by weaving new with old. After 35 days of protesting in the same square from 6.30pm, my respondents have shared many insightful comments on how their bodies and minds “learn” places and situations, how they make new routines, sensing, thinking and moving with otherwise unusual spaces.
Secondly, that a porous definition of a research field can allow all kinds of interesting and important topics to seep into a project (and I realise that I may come to bitterly regret this). During the last month, the metro passengers from my PhD project have made me interrogate the assumptions built into my questions and methods much more carefully. I had not planned to reduce respondents to mere “passengers”, dots whizzing between A and B and back again. But as the protests became Sofia's daily reality, it grew ever more important to locate the interest in commuting habits in relation to the myriad of subjectivities and environments that made up participants' everyday lives. Are the political beliefs of the interviewee relevant? Whether they own a dog (which must be walked before 8pm)? Their views on walking outside with an open beer can?
These are only some of the ways in which this project on daily mobilities is being illuminated from angles I did not anticipate. No big insights or exciting theories, a lot of work yet to be done and decisions to be made, and all kinds of traps to fall into. For now, I can see that thousands of people are craving political change, and even more people are loving the change happening already, in the city's streets. There is a six-lane road which is now a place where families spend the warm summer evenings sitting on the tarmac; kids are roller-skating, people are cycling, walking their dogs, eating ice creams. As I walk home just before midnight, Sofia's streets are quiet, and the air is cleaner than ever.
N.B.: This post was written on 18 July 2013. On 23 July, tensions in Bulgaria escalated. Protesters clashed with police during a blockade of the Parliament building, which left Members of Parliament trapped inside overnight.
Anna Plyushteva is a PhD candidate at UCL Geography exploring socio-technical change in the context of urban mobility. She is partially funded by a Doctoral Grant from the Economic and Social Research Council. More details on her research can be found here: http://www.geog.ucl.ac.uk/about-the-department/people/research-students/anna-plyushteva