ESA's CryoSat Validation Manager in the field (credits: M. Davidson)

From Malcolm (ESA), NL, 13 May

While there are still several teams on the ground finishing off their measurements, the successful ASIRAS flight over T15 on the Greenland ice cap this past Monday following the royal visit on Sunday marks the official end of the ESA CryoVEx campaign for 2011.

This has been a remarkable campaign in many ways. One element that comes to my mind is the sheer size of the effort. At times, we have had up to 50 scientists working on land ice or on sea ice across the Arctic, taking dedicated measurements from the air and on the ground – all contributing to CryoSat validation.

In addition to a ship or two lodged in the sea ice supporting teams on the ice, there were occasions during the campaign when up to four planes were in the air at the same time moving across the ice like a performance of aerial ballet making coordinated measurements of ice conditions below.

Icebreaker KV Svalbard (credits: A. Renner)

It was fantastic to see, for instance on April 15, the combined flights of the NASA IceBridge team, the DTU-team and their Norlandair Twin Otter with ASIRAS on-board and the AWI Polar-5 with EM-Bird coming together.

Polar-5 towing the EM-Bird over ice (credits: C. Haas)

Another personal highlight was my visit to T15 this past Sunday with high-ranking representatives from ESA, University College London, WWF-Netherlands, Oil and Gas Industry and the Dutch Royal Family.

HRH Prince Willem-Alexander of the Netherlands (right) being met by Santiago de la Peña on the Greenland ice cap (credits: V. Liebig)

It provided a unique opportunity to illustrate vividly on-site the scientific goals of the CryoSat mission and environment that the satellite is now measuring so precisely from space.

It also highlighted the role of ground and airborne measurements in ensuring that the maps generated by CryoSat will be of unprecedented accuracy.  These ensure a better monitoring of changing polar ice conditions and provide a better understanding of long-term trends.

NASA P-3 aircraft (credits: NASA/IceBridge)

The fact that the campaign worked out so well is a tribute to the dedication of the CryoVEx teams and their efforts in the field, and to the excellent collaboration and coordination between ESA, NASA, airborne and ground teams.

Henriette Skourup monitoring ASIRAS on the Twin Otter (credits: M. Davidson)

Lastly, the first-ever ESA blog for a campaign – maintained by our indefatigable Honora Rider – provided the opportunity for all participants to share their work and experiences on the ice.

I would like to thank all my ESA colleagues and campaign participants for your contribution and for your hard work. The next steps in analysing the data and putting the results together should be very exciting and valuable indeed.

I sign off with a few photos containing some of the highlights of the CryoVEx campaign.

Christain Haas from the University of Alberta looks forward to the next campaign (credits: J. Bekers)

Beautiful day on the fast ice (credits: K. Giles)

Blue ice ridge (K. Giles)

Wind-blown snow over Greenland (credits: M. Studinger)

Taking measurements with the ground EM31. Icebreaker Lance, the helicopter and EM-Bird are in the background (credits: H. Goodwin)

The team before leaving for Resolute (credits: S. Laxon)

Polar bear strolling past a corner reflector (credits: P. Assmy)

Twin Otter carrying ASIRAS (credits: M. Davidson)

We have been able to underfly several CryoSat passes. A few of them were in formation flight with the AWI Polar-5.

We have visited five main validation sites, circled in red on the map: Devon ice cap, Austfonna ice cap, the EGIG line Greenland interior, as well as sea ice north of Alert and sea ice around Svalbard in the Fram strait with our colleagues down on the ice below.

Flight tracks from DTU Twin Otter carrying ASIRAS (credits: H. Skourup)

It has been a pleasure to working with all those involved and I want to thank everybody for the great collaboration and excellent timing.

As you may have already have noticed, the corner reflectors are giving very valuable information of the radar penetration depth.

The updated version of the ASIRAS radar has a realtime display so we can see whether we have hit the reflector as we fly over. This demands very precise navigation as the reflector has to be within 10 m of the aircraft track.

Thanks to our highly-skilled air crew we only missed 2 or 3 reflectors out of 45 passes.

For our part, the airborne campaign has been a success, and we have now a collection of unique measurements to work with.

Over the last days we have been continuing with the work on the sea ice north of Svalbard, detailing snow elevation and thickness, taking ice-thickness measurements  and sampling other physical properties of snow and ice.

The EM-Bird and helicopter taking measurements of sea ice (credits: H. Goodwin)

The weather had not been very favourable for long EM-Bird flights, but this changed last Wednesday and we managed to do three flights in one day, covering over 650 km at around at around 81°N 16° E.

We had a long 48-hour station on the sea ice where the various groups carried out their work. This included divers sampling flora and fauna the under ice, biologists doing incubations under the ice, oceanographers rigging up their turbulence instrumentations, and of course sea-ice physicists carrying on with their experiments.

Taking measurements with the ground EM31. Icebreaker Lance, the helicopter and EM-Bird are in the background (credits: H. Goodwin)

Again, transects were set up for snow elevation and thickness, ice thickness and of course flights over the lines with the EM-Bird. The ice floe was pretty big, so some additional long EM31 and snow-thickness lines were possible. This time, snow pits and ice cores were drier than at the last station.

On Thursday evening at 23.45 we took off with the EM-Bird again to fly along CryoSat's track as the satellite orbited above. We also did a couple of parallel lines.

Liv, the EM-Bird, must have felt that this was a rather important flight, given that we were the only group left in this area with the opportunity to collect data for calibration, and promptly started to play up...

After a rather tense 30 minutes with various restarts of the bird, computers and the software, things finally stabilised. In the end, we were in the air for 2.5 hours and managed to acquire data along more than 200 km of flight track. The lie-in the following morning was well deserved for heli-crew and EM-Bird operators!

Mikko Lensu from FMI setting up the laser for snow elevation measurements (credits: H. Goodwin)

While they slept, the rest of the sea-ice team went out and measured the usual stuff on a floe that was perfectly aligned to CryoSat's track of the night before.

A short flight in the afternoon over the marked transects made the station complete and concluded the phase of the icebreaker's cruise dedicated to CryoSat validation work.

Marie Dumont with a snow sample (credits: H. Goodwin)

The cruise will now continue with more ice station work and an open ocean transect. We will continue to collect snow and ice data and fly whenever the weather permits.

We've had a very successful 10 days, during which we managed to collect a comprehensive dataset that describes the state of the sea-ice cover north of Svalbard – at both small and large scales, from snow pits and point measurements to kilometres of ice-thickness measurements.

This has only been possible thanks to the great support of the ship and helicopter crew who so often managed to get us to the right location at the right time – not an easy task in the ice covered Arctic!

The storm conditions at Thule Air Base were downgraded from Charlie to Bravo and we were able to take off at 10:52 LT in fairly poor visibility on the runway. Shortly after takeoff, the conditions deteriorated again to Charlie and the airfield was closed for a short time, while we were airborne.

Devon Ice Cap - CryoSat campaign camp marked by symbol (credits: M. Studinger)

Only the targets on the east side of Greenland showed good weather today, but these areas require a 7.5-hour flight to be surveyed efficiently. We had only a 5-hour window to work with and decided to fly the Devon Ice Cap mission despite some clouds in the area. We had to drop the Barnes Ice Cap from the mission plan because of time restriction, but were able to add the 20 April CryoSat orbit to the mission and two glacier runs over Bylot Island.

We encountered more clouds over the Devon Ice Cap than expected from the forecast and had to change flight elevation occasionally. We were able to survey the critical parts at 1,500 ft AGL and got good data.

CryoSat team camp on summit of Devon Ice Cap (credits: NASA/Digital Imaging Sensor)

A phone call with the CryoSat campaign field party shortly before takeoff confirmed good conditions at least over the Summit Camp on the Devon Ice Cap. We flew over the camp and the corner reflectors several times. Conditions changed quickly. On the last flight we could barely see the camp.

The goals of the CryoSat experiment on Devon Island are to assess the accuracy of surface elevations derived from CryoSat-2 L2 data; to assess the potential for CryoSat-2 data to be used for mapping snow accumulation over ice caps across the Queen Elizabeth Islands and to relate CryoSat-2 waveforms to surface and near-surface conditions on the ice cap. In order to do this it is necessary to continue measurements along the original CryoSat cal/val transect (ASIRAS Line 623) to maintain long-term thickness changes measurements that began in 2004.

Bylot Island (credits: M. Studinger)

The ATM lasers got 75% surface returns over the Devon Ice Cap and 90% over the two glaciers on Bylot Island. The snow, Ku-band and accumulation radars lost some data due to altitude changes necessary due to a loss of forward visibility.

With today’s flight, IceBridge has completed all three missions of the joint experiment with ESA’s CryoVEx teams.

Mark your calendars for the upcoming Fall AGU in San Francisco. We all have some landmark data sets to show!

Adapted from Michael Studinger's NASA IceBridge Flight Report for 5 May

As the team prepares for the Greenland leg of the campaign, this new image, derived from CryoSat data, shows the summit of this vast ice cap.

Plot of Greenland ice sheet (credits: ESA) - Click for full size

The profile, which runs from south to north over central Greenland, shows the height of the ice cap – peaking at over 3000 m above sea level.

Next week will be the last step in the year's campaign with scientists from various institutes working together to gather airborne and ground measurements of the ice and snow on land.

One of the challenges for the CryoSat mission is being able to acquire accurate measurements of two different types of ice. The missions sets out to acquire measurement of the thickness of floating sea ice so that annual variations can be detected and to survey the vast ice sheets that blanket Greenland and Antarctica accurately enough to detect small changes.

The validation field campaign for CryoSat, therefore, goes to great lengths to acquire in situ measurements of both types of ice.

The focus is now of the huge Greenland ice sheet.

Polar bear strolling past a corner reflector (credits: P. Assmy)

We've been aboard the RV Lance with two scientists from the Finnish Meteorological Institute who joined our NPI sea-ice physics group. Physical oceanographers, marine biologists looking at pelagic, benthic and ice-associated organisms, bio-geochemists, and a dive team are also on the icebreaker, making this a very mixed and interdisciplinary crowd!

We left from Longyearbyen on the 26 April and headed back to the ice we had been 10 days earlier. However, we were greeted by brash and broken floes. The bad weather we experienced at the end of the last cruise had broken up the continuous cover of first-year ice, leaving us with rather small floes that were not very suitable for CryoSat calibration and validation work.

So, after a rather short stop, Lance worked her way further into the ice pack in the search of larger floes. A few miles on, the pack was more consolidated with smaller leads between the floes. We managed to set up a two-day station for intensive sampling and surveying of the snow and sea ice cover.

RV Lance next to the ice station shortly before leaving. The ice broke up just after the last person left the ice (credits: A. Renner)

As part of the CryoVEx campaign, snow thickness, elevation, and ice thickness (by drilling and with ground electromagnetics) were measured on the first day along several parallel transects 140 m long. We complemented these measurements by sampling in snow pits and taking cores.

While the weather was not ideal, we got a short window for an EM-Bird flight. Our pilot got his first opportunity to get used to the load of the bird and the measurement procedures though 300 ft for calibrations were sometimes rather close to the clouds. Nevertheless, we managed to cover about 35 km and the EM-bird, called Liv, cooperated nicely after we had replaced a faulty power supply unit at the start of the cruise.

Taking measurements in a snow pit (credits: Y. Haapala)

On the second day, after a nightly visit by some polar bears, the weather was perfect for flying. So off we went again for a long flight north. Unfortunately, Liv got a bit grumpy and after about 40 km in the air decided not to work anymore. Back to the ship to troubleshoot...

Meanwhile, the Danish Twin Otter crew did their Austfonna flight and were ready to get into position and fly a transect over the corner reflectors we had set up near Lance.

In the afternoon, the sea ice folks on board were found looking patiently out the windows waiting to spot the small red Twin Otter plane and were very happy to see it when it finally arrived. A few loops by the plane over the transect seemed to inspire our Liv as well, and in the evening we managed another EM-Bird flight. We did some regional surveying as well as a nice overflight of the transect and several additional parallel lines.

All in all, it has been a very successful couple of days.

With a break in the weather, the weekend has proved very successful for the team in Svalbard.

Flying over Austfonna (credits: T. Casal)

We woke to sunshine on Saturday and heard from the ground teams on the Austfonna ice cap and the RV Lance icebreaker up north in the sea ice that the weather was quite good. So, we grabbed the opportunity fly the Twin Otter equipped with ASIRAS and the laser scanner to take some of the airborne measurements needed for this leg of the campaign.

Sea ice (credits: T. Casal)

The transit to Austfonna was breathtaking – the views were incredible, so pristine. The only trace of human activity were the occasional snowmobiles tracks from the ground team. 

Icebreaker RV Lance seen from the Twin Otter (credits: H. Skourup)

In morning we made all six flight lines that had been planned and in the afternoon we followed CryoSat's ground track from the day before, from Longyearbyen to the RV Lance icebreaker.

Flight lines across Austfonna and over sea ice (credits: H. Skourup)

We made eight flights of the validation line, but we only managed to overfly the corner reflectors in the last in the last 3–5 overflights as the sea ice had drifted 0.6 nm since they had been placed on the ice in the morning.

Over the next several days from 28 April–16 May, Arctic ice-thickness surveys will be taking place north of Svalbard, along CryoSat ground tracks.

Airborne measurements of sea-ice thickness are being conducted by the Norsk Polarinstitutt (NPI) in the sea-ice pack north of Svalbard using an EM-Bird from a ship-based helicopter, in combination with field teams taking measurements of ice thickness from the Norwegian vessel RV Lance.

Sea-ice concentration around Svalbare 20 April (credits: DTU/ESA/Polar View)

This AMSR-E satellite ice-concentration image shows the ice conditions north of Svalbard on 29 April, (Day 119) where this sea-ice component of the validation campaign is taking place.

The following ice chart from 28 April shows the corresponding interpretation of the sea-ice conditions by the Norwegian Met Service.

Ice chart showing sea-ice conditions on 28 April (credits: Norwegian Met Service)

Finally the plot below shows the CryoSat orbital ground tracks overlaid onto the map of the average April sea-ice edge in grey (and indicating the black outline of Svalbard). It also shows the days of potential airborne underflights of CryoSat by the AWI Polar-5 with EM-Bird and DTU Twin Otter with ASIRAS.  

CryoSat tracks over Svalbard 28 April to 5 May (credits: ESA)

The coloured legend with numbers indicates the digital dates of the coloured dotted CryoSat ground tracks, where day 118 = 28 April, day 121 = 1 May, and day 125 = 5 May.

The trick is for the ground teams to seek the best possible sea-ice location, over which the combination of coincident surface, airborne and satellite-borne data acquisitions are possible.

Naturally, we wish the NPI teams out on the sea ice the best of luck with the combination of sea ice and flight (visibility) conditions. Currently the perspectives look best to the northeast of Svalbard, where the ice conditions currently appear to be most favourable. Stay safe out there!

As various teams gather to kick off the measurement campaign around Svalbard, bad weather has delayed today's flights. Nevertheless, all the equipment is in place on the Austfonna ice cap and ready for when the weather is clear enough to fly.

One of the five corner reflectors on Austfonna (credits: T. Schuler)

A team of two from the University of Oslo spent the Easter week on Austfonna setting up the ground control points and preparing the base camp for the main campaign.

Five corner reflectors are now in place awaiting the overflight. As usual, conditions were difficult. This time, however, Easter brought surprisingly mild temperatures and rainfall all across the ice cap!

Maintenance work at an automatic weather station on Austfonna (credits: T. Schuler)

The resulting ice layer on top of the winter snow pack ensures an interesting stratigraphy. This layering will be studied in snow pits and by radar-profiling over the coming days by the main team. Four team members already out there working on the ice.

The remaining three team members are stuck in Longyearbyen due to bad weather and the overflight that was scheduled for today has unfortunately been postponed. Hopefully, the weather will clear soon and we can begin in earnest.