Archive for the ‘Ground based measurements’ Category


Fig. 1 Scoria cones surround the runway


During the course of the GEOmon project, a new deliverable was introduced to install air sampling and monitoring equipment on Ascension Island with an aim to monitor CO2 and methane.

Dave Lowry and Rebecca Wilson bravely accepted the onorous task of installing the equipment and reported back to us on the rigours of their trip. Thank you to Dave for the engaging report and the wonderful photos!

We left RAF Brize Norton late on June 16 on the scheduled Air Seychelles flight to the Falkland Islands via Ascension. Eight hours later we approached the aptly named Wideawake airfield for touchdown between the imposing deep red-brown scoria cones (Fig. 1), and were whisked off to the Obsidian Hotel (the only hotel) in the administrative centre and island port Georgetown. One of the distinctive fleet of white Fiestas allowed us to travel around the island and get back to our main workplace for the week, the Met Office building at the airport. Waiting patiently for our arrival were numerous boxes of equipment sent 3 weeks prior, but not our vital calibration gases.

Within 3 hours the main equipment was set up and operational in the air conditioned server room, measuring carbon dioxide and methane concentrations. Our Met Office host, Vicky Huntly, got to work persuading the services guys to help us set up the air inlet. The following day we had two holes drilled through the wall and our air line outside and sampling the South Atlantic breeze, but it would take a further 4-days of waiting before we could get our airline attached to a mast above the buiding. With our calibration cylinders having been pushed off two flights by more important military cargo, we had the weekend to fret over their arrival on the Monday morning flight and the last chance to complete the installation before we left. 


Fig. 2 Lush plantations cover the summit ridge of Green Mountain


Still, no point worrying about it when there was a whole 100 square kilometres of island to explore and many air samples to be collected to prove that our new site at the airhead was as representative of South Atlantic air as anywhere else on the island. Ascension has some of the most constant winds in the world, the SE trades. It is largely barren scoria and lava desert around the edges, but lush Green Mountain in the centre (Fig. 2) spends half of the time in clouds and provides an amazing contrast, the top of the peak having no view due to dense plantations of bamboo, bananas and ginger, and on the lower slopes, frequent sightings of the native orange or purple land crabs (Fig. 3).  The island was the site of a NASA tracking station for the Apollo missions, and is currently the site of an ESA tracking station for Ariane. Air was collected at both of these sites (Fig. 4), as possible future alternatives to the airhead.


Fig. 3 Orange land crab on the defensive


The coast of Ascension is a hive of activity, although not of the human variety.


Fig. 4 Rebecca collecting air at the edge of the old NASA tracking site


Pale sandy beaches nestle between rugged black basalt lava flows (Fig. 5),


Fig. 5 Typical NE coast of Ascension


Ascension frigate birds (Fig. 6) fly in squadron back to their only nesting site on the guano-capped Boatswain Bird Island (Fig. 7), spotted crabs fight for supremacy of the rock pools (Fig. 8), and the carnivorous Black Trigger Fish patrol the shallow aquamarine pools (Fig. 9).


Fig. 6 Ascension frigate birds



Fig. 7 Boatswain Bird Island, home of the frigates



Fig. 8 Spotted sea crab



Fig. 9 Blackfish await meal


The icon of Ascension Island and the focus of most conservation effort are the Green Turtles, the deep nests of which cover most of the sandy beaches on the island (Fig. 10). June is the end of the hatching season. An evening torchlit stroll saw a few struggling toward the surf, a morning stroll outlined how many didn’t make it and one who needed some significant help to the water, to avoid becoming a dried-up husk in the midday sun (Figs. 11-13).


Fig. 11 Hatchling heading for the sea under cover of darkness



Fig. 10 Turtle nests at English Bay



Fig. 13 Turtle eggs uncovered on Long Beach, Georgetown



Fig. 12 This little mite was still breathing but exhausted and needed help to the surf


Such a barren, rugged and dry place this used to be, our sampling forays took in the delights of the Devil’s Ashpit, the Devil’s Cauldron and the Devil’s Riding School (Fig. 14),


Fig. 14 Devil’s Riding School crater, filled with dark and light ash layers, some reworked by water


first described by Darwin on route home from South America, an ash-filled and lake-sedimented crater, with it’s distinctive layer of Devil’s Eyeballs (Fig. 15).


Fig. 15 The water-deposited layer with Devil’s Eyeballs.


Monday morning came around all too quickly and with everything crossed we headed back to the Met Office to await news of the incoming flight. Call came through at 9:45 and 15 minutes later a forklift rolled up to the door with 2 crates of cylinders. Devoid of appropriate equipment a geological hammer and chisel opened the crates beautifully. Two hours of plumbing later the first calibration gases flowed out of the cylinders and into the instrument. A revised plan was hatched to put a temporary air inlet on a mast above the Met Office building and on our final afternoon this was put in place and monitoring of greenhouse gases on Ascension started in earnest (Fig. 16), a big relief having spent the last year with help from UEA developing the auto inlet and software and calibrating the instrument.


Fig. 16 Screenshot of the first morning of methane data


We were visited by the Ascension Island administrator, Ross Denny (Fig. 17), who is keen that the installation is publicised in the local Islander newspaper.


Fig. 17 – Dave, Rebecca and Ross Denny admire the new equipment


The Met Office have promised to send the data files produced on a daily basis and the first results look very interesting. Despite the financial requests of the Cable and Wireless monopoly, remote data transmission and login is likely to follow.

Next up for installation is the Falkland Islands, hopefully in October this year.


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Part of the reason for the GEOmon blog is to get to know the people who work on the project. Our first profile is of Zoë Fleming who works in Activity 2. She is also chairing the GEOmon Gender Committee this year, helping to ensure that the conditions are in place to allow women to develop their careers in science.


Zoe up a tower at the Weybourne atmospheric observatory

I have been working on the trace gas project of GEOMON for just over 2 years and have enjoyed the international and interdisciplinary nature of being a part of this community. I grew up in Brussels and then moved to Edinburgh to study Environmental Chemistry.

My first research experience was at the Leibniz Institute for Baltic Sea Research, Warnemünde, Germany, looking at atmosphere-ocean interactions, which included laboratory work and field work in the Baltic Sea and the Arctic Ocean. I then did a PhD in Leicester, England, measuring the radicals that are involved in tropospheric ozone formation. I have since worked on field work in Antarctica with Imperial College and the British Antarctic Survey, for Greenpeace International’s research unit and researching the communication of climate change and sustainable development issues at De Montfort university.

Weybourne footprint for May 2008

A plot of the monthly footprint of the air arriving at Weybourne using the Met office's NAME dispersion model.

I am now working for the UK National Centre for Atmospheric Science (NCAS), based at Leicester University on determining trends in atmospheric trace gases at measurement stations around Europe and in the Atlantic ocean. Part of my work involves the GEOMON harmonisation and comparison of European trace gas datasets and detecting trends in ozone across Europe.


Zoe measuring Persistant Organic Pollutants in the Arctic Ocean

At present I am only doing data analysis and no longer do field work or take measurements myself but studying the meteorology and characteristics of the measurement stations does bring the data to life and make me content in being an environmental scientist. Knowing that our research contributes to future air quality and carbon reduction policies makes me feel like I am doing my bit to understand and protect our environment.

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In a project funded by the French National Research Agency we are trying to estimate the CO2 emissions from Paris by measuring the atmospheric concentration in and around the city. Our first site is the top of the Eiffel Tower. It’s a nice choice for a measurement site, high and central enough to see air from across the city and the local air quality association AIRPARIF already have a measurement station there.

There’s just one problem: in a few days of test data we collected in June there is this spike around 9am each morning. It’s not traffic; that starts much earlier. It’s almost certainly the arrival of the first tourists at the top viewing platform. Now when we said we wanted to measure the human impact on the atmosphere this is not quite what we meant.

Resorting to the back of the nearest envelope, I think humans respire about 75kg of carbon each year. Even in a city with the unusual population density of Paris that should be dwarfed by emissions from vehicles. We were careful not to make the measurement too close to any car exhaust but we hadn’t thought enough about breathless tower-climbers.

AIRPARIF hadn’t noticed this either since they usually only measure things that humans don’t produce. The solution: Hopefully we can just move the air intake.

[thanks to Ulysses Greene from Flickr for the photo]

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