Stefan Ligtenberg
PostDoctoral researcher

About me


I am a postdoctoral researcher in polar meteorology and glaciology at the Institute for Marine and Atmospheric research Utrecht (IMAU), Utrecht University, The Netherlands.

Agenda

Latest publications

16 Feb. 2017
The Firn Model Intercomparison Project paper is out, published in Journal of Glaciology. Details.

25 Jan. 2017
Results of the seismic experiments around the firn aquifer site in southeast Greenland, published in Frontiers of Earth Science. Details.

21 Jan. 2017
Model comparison of firn meltwater retention on the Greenland Ice Sheet, published in Frontiers of Earth Science. Details.

08 Dec. 2016
Spectacular meltwater features found in an East Antarctic ice shelf, published in Nature Climate Change. Details.

Blog

Welcome to my blog. Here, I will write about interesting field trips or random science facts. My first blog will be about the SEES expedition to Edgeøya, Svalbard

Blog #7, 14 September 2015

Closing remarks

Number 7

Blog #6, 25 August 2015

History lessons

The SEES expedition was initiated as follow-up research of the Dutch Kapp Lee station during the 1970s and 1980s. In the summer of 1968, four brave men build up the research station and spend 14 months on Edgeøya in the name of science. Three of them are also on the current cruise and are full of unbeleivable stories. Last night, a 30-minute lecture by one of them turned into more than two hours of storytelling about life during polar winter, research and friendship.

They were dropped of by a ship with materials to build their research station -and temporary home- and enough fuel and food for at least two years. For drinking water, they build a small dammed lake and melted the ice in winter. Apart from a couple of hunters and one other research station on Edge&osalsh;ya, the only other contact was by radio. Unfortunately, the atmospheric conditions were so miserable that they only had about 10 minutes of contact with The Netherlands in total. Quite isolated indeed!

Their main research topic was the presence of polar bears. With a sedation gun they put the polar to sleep to measure it characteristics and label it. However, the sedation only worked after a couple of minutes and the gun should be shot from less than 30 meters, leading to some tricky situations. During their stay they sedated 12 different polar bears. In polar winter, they went on many multi-day field trips with huskies and a sledge to find holes of pregnant polar bears. Through temperatures of -30 and snow storms they searched around the islands of Barentsøo;ya and Edgeøya and eventually found no hole during their 14 months stay....

Sometimes, science is very hard work without any reward. However, the work they did was a very solid basis for the current Dutch polar research community. Also, their stories make me very much appreciate our current research environment. Although the conditions and region are quite though, we can still sleep in a nice, dry bed and take a hot shower after a whole day in the cold drizzle.

A small note about other things on board. The weather station works like a clock and the data can be viewed online here. Yesterday, we sailed through the Freemansundet, also know as polar bear highway. Both planned landings were postponed due to polar bear presence and we saw one mother with two cubs swimming through the water. During the afternoon landing we watched the impressive glacier front of the Freeman Glacier and even spotted a polar bear walking along the shore: a very impressive sight. Today, I will assist in drilling a sediment core in a lake, which will be used to study the vegetation and geological history of the region. More details can be found on the blog of Lineke Woelders: click here!

Blog #5, 23 August 2015

Up and running

Our goal during the SEES expedition has been succesfull! Yesterday, we installed the automatic weather station (AWS) on Ulvebreen, a glacier in the east side of the Spitsbergen. Our group contained 9 people in total: 2 armed guides, Willem Jan, Peter and me from IMAU, a reporter and cameraman from the NOS and two expedition members that were needed to carry extra bags. We all had our backpacks full of aluminium poles and instruments, but of course also enough food, water and extra clothes.

Fog appeared when we boarded the zodiacs to land near the glacier, making it both difficult to navigate close to the glacier and check for polar bears on land. The guides navigated very carefully and we were lucky to eventually land on a beach very close to the glacier, but a safe distance from the 40 meter high glacier front. After a 1,5 hour walk over the glacier we reached our designated AWS location: a relatively high and flat spot on the middle of the glacier. There were a few crevasses in the glacier, but they were visible making navigation quite easy.


Our lunch stop half way up the glacier.

Setting up the AWS went quite smooth. Willem Jan was in charge of drilling a 15 meter deep hole with a steam drill. In this hole, we let a steal wire freeze in that will melt out during the next summers measuring the ablation rate of the glacier. Peter and I focussed on the weather station. First, we made sure that the base and pole were connected properly, before putting the construction on its side and installing the instruments. This is quite a delicate job, especially with gloves and cold fingers. After 3 hours of hard work, we erected the station again and made some final adjustments to let it stand as straight as possible. Via a bluetooth connection, we looked at the output and all instruments returned realistic results, indicating that the station works! Yay!


Me in front of the working weather station.

While working on the AWS, the fog reappeared and with it a cold wind. Within the hour, the weather changed from a sunny 8 degrees to almost freezing. On our way back, some meltwater was refrozen on the surface, giving it a different look than on the way up. Half way down, we reached the cloud base and had a perfect view over the glacier, fjord and our boat in the distance. After 8 hours, we were satisfied and safely back on board!


The way down with a view of the fjord and our boat Ortelius in the far distance.

The station runs on solar power in summer and on batteries in winter and is expected to have enough power to operate for 5 years without servicing. Hopefully, it will also survive the presence of polar bears and the occasional winter storm. The data is send to Utrecht via a satellite system, so the data can be used in real time. The data will be mainly used to evaluate our climate model and study the changing climate over Spitsbergen glaciers.

14 september: A nice video about our glacier adventure has been made by the team of the NOS (Martijn Bink and Ruben Kocx) and can be watched on Youtube: click here.

Blog #4, 21 August 2015

Edgeøya and sea sickness

This morning we arrived at the main destination of our expedition: Kapp Lee at Edgeøya. At this location a Dutch research station was present during almost 20 year during the 1970s and 1980s. A lot of biologists and ecologists are very much looking forward to research this area again. The same is true for a few of the old inhabitants of the station that are on the expedition. These groups are the first to land in the zodiacs, and the other participants are shipped later. Giving me just the hour I need to write this blog!

These last few days, the program has been quite full with lectures, meetings, whale watching and preperation for the different science programs. Also, the first evening and night on the boat were quite rough, causing sea sickness by many of the passengers. The weather and wind were not even that bad, but the swell coming from the Atlantic made the boat roll. And since this was our first night on the boat, most people went to bed straight after dinner. After we rounded the southern point of Spitsbergen (Sorrkappen) we are not on the open ocean anymore, making it much more enjoyable on the boat.

It is very likely that tomorrow will be our d-day. The weather is forecasted to be calm, so if there is no polar bear on land, we will hike up to one glacier at the eastside of Spitsbergen: Ulvebreen or Usherbreen. Ulvebreen is a glacier that ends in the sea -a so-called marine-terminating glacier-, meaning that there are crevasses on the front of the glacier that we should carefully navigate around. Usherbreen ends on land and is therefore a lot safer, but more difficult to reach because of the tundra, rivers and mud fields in front of the glacier. If we arrive at the site tomorrow morning, we will decide last-minute which one it will be.

The internet is very slow on the boat and everyones tries to stay in touch with home, so I am hoping that this blog will reach the world in time. Unfortunately, it seems impossible to upload photo's to the blog. I will upload some photo's at the end of the expedition.

Blog #3, 19 August 2015

Glacier practice

Just a short blog before we are going on board of the Ortelius, our home for the next 9 days. At 4 pm, we have to be at the small harbour in Longyearbyen and the scheduled departure is 6 pm. It is said that there will be internet on board of the ship, but with 55 scientists trying to work and blog it remains to be seen if the bandwidth will hold up. Hopefully, I will be able to keep this weblog up to date and post an occasional picture.


The Ortelius is waiting for us!

Yesterday, Willem Jan and I had a free day so we decided to book a guided hike to the glaciers above Longyearbyen. Without a gun you are not allowed to go beyond the city boundaries, so this was the only option to see something of the surroundings. It turned out that our guide Greve was very interested in glaciers, so in the end we spend most of our time walking on ice. A surprisingly good practice for our weather station expedition. Next to this, the hike was very beautiful, despite the typical Spitsbergen weather: drizzle and windy. We hiked up through the river bed and moraines to the Lars glacier, where we studied the meltwater rivers cutting into the glacier surface. Surface meltwater collects in streams and small rivers that cut into the ice with time. The longer it works, the deeper it becomes.


Melwater river on Lars Glacier.


A dangerously deep inclined meltwater channel.

After an hour on the glacier we hiked up to the Sarkofagen mountain. We were lucky enough to have some sunshine, providing stunning colors and even a small rainbow over the city of Longyearbyen. The descent was as always al lot more comfortable than the way up. Walking down over the other glacier in the valley, the Longyear glacier, with a view on the sunlit valley and town was a real treat. Since the hike through the moraines and over the glacier surface was less difficult than we imagined, we are more confident that -weather permitting- we will be able to install the automatic weather station.


The Lars Glacier from above with in front the meltwater channel of the first picture.


The accompanying husky Balman jumps over a meltwater river.

Blog #2, 17 August 2015

Arrived on Svalbard

Today I arrived in Longyearbyen and the trip by plane from Oslo was already worth the journey. We were very fortunate to have excellent weather conditions above Norway: clear skies all the way from Oslo to the Arctic Ocean. And luckily, I had a window seat! It started with the green rolling hills of southern Norway with the occaisional lake, which slowly turned into more and more baren mountains. After an hour we reached the Norwegian coast around Bødo and had a great view of the Svartisen ice caps, the second and forth largest ice fields in Norway. In the picture below you see them both with the Engabreen glacier as outlet glacier in the front.


Glaciers Svartisen West (front) and East (back).

After this we also had an excellent view of the beautiful islands of the Lofoten before flying over the Arctic Ocean. Above the ocean the clouds started to appear, in line with the weather forecast for Svalbard: overcast. These clouds, however, made the entrace to Svalbard all the more impressive. The plane descended through the clouds and all of sudden there it was, a mixture of ocean, brown rock and ice: Svalbard. A collective 'wow' filled the plane. Although it looks more or less like you would expect, it is impressive since it stretches out as far as your eye can see. Also striking was the 'ugly' look of the glaciers! You might expect nice white snowy areas at the top with blue glacier tongues, but the glaciers contained hardly any snow at all and are very dirty from dust, rocks and sediment.


A Svalbard glacier near Sveagruva.

The difference between the Svartisen ice fields on the Norwegian mainland and the Svalbard glaciers shows the large impact of climate change on Svalbard. A 'healthy' glacier -one that is in equilibrium with the climate- has a large upper area where snow can accumulate and a relatively small lower icy area where it melts. The ratio is often somwhere close to 70-30. The glaciers seen from the plane, however, are nowhere close to this ratio and therefore very out of balance. This means that a lot more ice will melt away. All the more reason to try and get this message across to as many people as possible!


A typical Svalbard valley: glacier tongue, river and sediment cone.


A view of Longyearbyen from one of the old mining ruines.

Blog #1, 16 August 2015

It has started!

After months of preperation and anticipation, my trip with the SEES expedition to Svalbard has finally started. SEES stands for Scientific Expidition Edgeøya Svalbard and will be the largest polar expidition is the Dutch history. During the expedition we will make a 9-day scientific cruise with the ship Ortelius that is operated by Oceanwide Expeditions, a company specialized in polar travel. The cruise starts in Longyearbyen, from where we sail south around the main island of Svalbard to Edgeøya, the southeastern island of the archipelago. On this island, Dutch polar research was conducted during the 1970-80s and the main objective of SEES is to use these results and compare them to the current state of the island; what has been the influence of climate change.

There will be slightly over 100 people on board of the ship, from which roughly half are polar scientists from a broad range of fields: meteorology, biology, ecology, but also archeology and social sciences. There will also be 30-40 tourists travelling with the so-called Arctic Academy, they will have there own program but can follow the scientific research and follow lectures. The group is completed by a number of journalists, politicians, and artists that will help to fulfill another major goal of SEES: public outreach. By reporting about the expedition, we hopefully inform the public about the large impact of climate change on such a remote and untouched ecosystem and about polar research in general. Hopefully, my blogs will also help!

I'm writing this blog during my flight to Oslo, where I will spend the night before flying to Longyearbyen, Svalbards capital and only proper village, tommorow morning. A lot of people know that Svalbard is within the Arctic Circle and somewhere above Norway, but it is actually far north of Norway. If you would go as far south as Svalbard is north of The Netherlands, you would end up halfway the Sahara on the border of Algeria and Mali. It is that far north. And it is that far inside the Arctic Circle that the sun does not set for more than 4 months during summer. Most of you realise that this also means that, in winter, there is no daylight for more than 4 months... Due to this long and cold winter, the east part of Svalbard is encapsulated by sea ice for the largest part of the year. Only during the summer months (June - August) the land is snow free and vegetation will grow and bloom. Of course this is all information found in books and on the internet, so I'm happy to write about my own impressions during the following two weeks!

Finally, a note on my scietific contribution to the expedition. Together with my colleague Willem Jan we will try and install an automatic weather station on one of the glaciers in southeast Svalbard. I specifically say 'one of' as we have 5 possible locations, and therefore 5 different hiking routes all with their own risks and difficulties. Since we are part of a larger expedition we have to follow the ships itinerary, meaning that we only have a short time window to go ashore. If we are unable to land due to weather or ocean conditions, or the precense of polar bears, we skip the location and go to the next. The weather perdictions look good, so we have good hopes to land at leats once! If we are able to land, we will have 6-8 hours to hike over the tundra and the glacier surface to the ideal weather station location, install it and hike back. During one of my following blogs, I will provide more details about what the weather station measures and why this is important.

That's it for now, my next blog will be from Svalbard!