Category Archives: Iridium

Greenland Oceanography by Sled and Snowmobile

Wind chill matters in Greenland because one must see and breath. This implies exposed skin that will hurt and sting at first. Ignoring this sting for a few minutes, I notice that the pain goes away, because the flesh has frozen which kills nerves and skin tissue. The problem becomes worse as one drives by snowmobile to work on the sea ice which I do these days almost every day.

Navigating on the sea ice by identifying ice bergs with LandSat imagery. The imagery also shows polynyas and thin ice in the area. [Photo Credit: Sonny Jacobsen]

Mar.-22, 2017 LandSat image of study area with Thule Air Base near bottom right, Saunders Island in the center. Large red dots are stations A, B, and C with Camp-B containing weather station, shelter, and first ocean mooring. My PhD student Pat Ryan prepared this at the University of Delaware.

My companion on the ice is Sonny Jacobsen who knows and reads the land, ice, and everything living on and below it. He teaches me how to drive the snowmobile, how to watch for tracks in the snow, how to pack a sled, and demonstrates ingenuity to apply tools and materials on-hand to fix a problem good enough to get home and devise a new and better way to get a challenging task done. Here he is designing and rigging what is to become our “Research Sled” R/S Peter Freuchen, but I am a little ahead of my story:

Sonny Jacobsen on Mar.-27, 2017 on Thule Air Base building a self-contained sled for ocean profiling.

First we set up a shelter in the center of what will hopefully soon become an array of ocean sensors and acoustic modems to move data wirelessly through the water from point A in the north-west via point B to point C. Point C will become the pier at Thule Air Base while the tent is at B that I call Camp-B:

Ice Fishing shelter to the north-east of Saunders Island seen to the left in the background.

Next, we set up an automated weather station (AWS) next to this site, because winds and temperatures on land next to hills, glaciers, and ice sheets are not always the same 10 or 20 km offshore in the fjord. It is a risk-mitigating safety factor to know the weather in the study area BEFORE driving there for 30-60 minutes to spend the day out on the ice. It does not hurt, that this AWS is also collecting most useful scientific data, but again, I am slightly ahead of my story:

Weather station with shelter at Camp-B with the northern shores of Wolstenholme Fjord in the background. Iridium antenna appears just above the iceberg on the sidebar of the station. Winds are measured at 3.2 m above the ground.

With shelter and weather station established and working well, we decided to drill a 10” hole through 0.6 m thin ice to deploy a string of ocean instruments from just below the ice bottom to the sea floor 110 m below. Preparing for this all friday (Mar.-24), we deploy 22 sensors on a kevlar line of which 20 record internally and must be recovered while 2 connect via cables to the weather station to report ocean temperature and salinity along with winds and air temperatures. It feels a little like building with pieces of Lego as I did as a kid. Engineers and scientists, perhaps, are trained early in this sort of thing.

Weather station with ocean mooring (bottom right) attached with eastern Saunders Island in the background on Sunday Mar.-26, 2017.

Sadly, only the ocean sensor at the surface works while the one at the bottom does not talk to me. I can only suspect that I bend a pin on the connector trying to connect very stiff rubber sealing copper pins from the cable with terminations equally stiff in the cold, however, there are other ways to get at the bottom properties albeit with a lot more effort … which brings me to R/S Peter Freuchen shown here during its maiden voyage yesterday:

R/S Peter Freuchen in front of 10” hole (bottom right) for deployment of a profiling ocean sensor. The long pipes looking like an A-frame on a ship become a tripod centered over the hole with the electrical winch to drive rope and with sensors (not shown) over a block into the ocean. This was yesterday Mar.-28, 2017 on the way from Camp-B back to Thule Air Base.

The trial of this research sled was successful, however, as all good trials, it revealed several weaknesses and unanticipated problems that all have solutions that we will make today and tomorrow. The design has to be simple to be workable in -25 C with some wind and we will strip away layers of complexities that are “nice to have” but not essential such as a line counter and the speed at which the line goes into the water. There can not be too many cables or lines or attachments, because any exposure to the elements becomes hard labor. This becomes challenging with any gear leaving the ocean (rope, sensors) and splattering water on other components. Recall that ocean water is VERY hot at -1.7 C relative to -25 C air temperatures. This means that ANYTHING from the ocean will freezes instantly when in contact with air. Efficiency and economy matter … as does body heat to keep critical sensors and batteries warm.

A big Thank-You to Operation IceBridge’s John Woods for something related to this post that I wish not to advertise 😉

Oceanography below Petermann Gletscher for 400 Days

Ocean data from 810 meters below sea level under one of Greenland’s last remaining ice shelves arrives every 3 hours at my laptop via a 3-conductor copper cable that passes through 100 meter thick ice to connect to a weather station that via a satellite phone system connects to the rest of the world. This Ocean-Weather station on the floating section of Petermann Gletscher has reported for 400 days today. I am still amazed, stunned, and in awe that this works.

The station started 20th August of 2015 as a small part of a larger joint US-Swedish expedition to North Greenland after friends at the British Antarctic Survey drilled holes through the Empire-State-Building thick ice shelf. It is powered by two 12 Volt car batteries that are recharged by two solar panels. When the sun is down, the car batteries run the station as in winter when temperatures reached -46 C. When the sun is up, the solar cells run the station and top off the batteries. The voltage during the last 400 days shows the “health” of the station:

Battery voltage at the Petermann Ocean-Weather Station from Aug.-20, 2015 through  Sept.-23, 2016. The polar night is indicated by slowly declining voltage near 12 V while during the polar day voltage is near 14 V with oscillations in spring and fall during the transition from 24 hours of darkness to 24 hours of sun light.

Battery voltage at the Petermann Ocean-Weather Station from Aug.-20, 2015 through Sept.-23, 2016. The polar night is indicated by slowly declining voltage near 12 V while during the polar day voltage is near 14 V with oscillations in spring and fall during the transition from 24 hours of darkness to 24 hours of sun light.

There is an unexplained outage without data from February 12-25 (Day 175-189) which happened a day after the first data logger shut down completely without ever recovering. Our station has 2 data loggers: A primary unit controls 2 ocean sensors, atmospheric sensors, and the Iridium satellite communication. The secondary unit controls 3 ocean sensors and the GPS that records the moving glacier. Remote access to the secondary logger is via the primary, however, each logger has its own processors, computer code, and back-up memory card.

Inside of University of Delaware command and control of five ocean sensors and surface weather station. Two data loggers are stacked above each other on the left.

Inside of University of Delaware command and control of five ocean sensors and surface weather station. Two data loggers are stacked above each other on the left.

The primary logger failed 11th February 2016 when we received our last data via Iridium satellites until Keith Nicholls and I visited the station 27th and 28th August 2016 via helicopter from Thule, Greenland. Since I could not figure out what went wrong sitting on the ice with the helicopter waiting, I spent a long night without sleep to swap the data logger with a new and tested unit. I rewired sensors to new data logger, switched the Iridium modem, transceiver, and antenna, changed the two car batteries, and now both data loggers with all five ocean sensors have since reported faithfully every 3 hours as scheduled as seen at

http://ows.udel.edu

Lets hope that the station will keep going like as it does now.

The major discovery we made with the ocean data are large and pronounced pulses of fresher and colder melt waters that swosh past our sensors about 5 and 25 meters under the glacier ice. These pulses arrive about every 14 days and this time period provides a clue on what may cause them – tides. A first descriptive report will appear in December in the peer-reviewed journal Oceanography. Our deeper sensors also record increasingly warmer waters, that is, we now see warm (and salty) waters under the glacier that in 2015 we saw more than 100 km to the west in Nares Strait. This suggests that the ocean under the glacier is strongly coupled to the ambient ocean outside the fjord and vice versa. More on this in a separate future posting.

Time series of salinity (top) and potential temperature (bottom) from four ocean sensors deployed under the ice shelf of Petermann Gletscher from 20th of August 2015 through 11th of February 2016. Temperature and salinity scales are inverted to emphasize the vertical arrangements of sensors deployed at 95m (black), 115 (red), 300 m, and 450 m (blue) below sea level. Note the large fortnightly oscillations under the ice shelf at 95 and 115 m depth in the first half of the record. [From Muenchow et al., 2016]

Time series of salinity (top) and potential temperature (bottom) from four ocean sensors deployed under the ice shelf of Petermann Gletscher from 20th of August 2015 through 11th of February 2016. Temperature and salinity scales are inverted in order to emphasize the vertical arrangements of sensors deployed at 95m (black), 115 (red), 300 m, and 450 m (blue) below sea level. Note the large fortnightly oscillations under the ice shelf at 95 and 115 m depth in the first half of the record. [From Muenchow et al., 2016]

P.S.: The installation and year-1 analyses were supported by a grants from NASA and the Jet Propulsion Laboratory, respectively, while the current work is supported by NSF for the next 3 years. Views and opinions are mine and do not reflect those of the funding agencies.

Greenland Calling: Iridium Satellite Phone

I have trouble calling Petermann Gletscher, Greenland where I am collecting ocean data that feeds into a remote weather station. This station is run on a pair of car batteries, because the solar panels do not work until the sun rises again in two months and the next electrical outlet is about 300 miles away. A computer controls power to sensors and a satellite phone. All calls from and to the station are routed via a commercial satellite phone system that consists of about 66 satellites orbiting our planet. They often appear as shooting stars in the night sky that are called Iridium flares. As beautiful as these orbiting satellites are, they have driven me mad.

Screen shot of Iridium satellite orbits observed in real-time from http://www.satflare.com/track.asp?q=iridium

Screen shot of Iridium satellite orbits observed in real-time from http://www.satflare.com/track.asp?q=iridium

Iridium satellite phones and modems connected to computers are the only way to get data from remote areas of the Arctic and Antarctic. Some modems send small text messages called Short-Burst-Data (SBD) while other modems support a true two-way dial-up connection that includes all the hand-shaking of a telephone call. This computer-to-computer calling is more tricky than the person-to-person calls that this system was originally designed for. Working near Petermann Fjord, we had much trouble with even the person-to-person calls. Senator John McCain’s of the U.S. Congress was rudely disconnected, when he called us on the ship while in Sweden working with Government officials. And the Iridium phones on our Swedish icebreaker I/B Oden were thoroughly checked by field technician Robert Holden:

Rob Holden testing Iridium phones above the bridge of I/B Oden.

Robert Holden testing Iridium phones above the bridge of I/B Oden in August of 2015.

The building and coding of this ocean weather station is cool stuff for someone like me who likes Legos, computer games, and hacking electronics. Our Greenland ocean observing system uses both the text message SBD system at two smaller stations and the dial-up system at the larger weather station. The SBD system is great for small burst of data smaller than 1960 bytes per message. The Greenland station makes the call to a ground station that then e-mails the message forward to us. The method is very reliable, but there are small connection gaps that become data gaps.

Inside of University of Delaware command and control of five ocean sensors and surface weather station. Two computers are stacked above each other on the left.

Inside of University of Delaware command and control of five ocean sensors and surface weather station. Two computers are stacked above each other on the left with satellite modem 9522B on bottom left with RS-232 cable connecting to computer (Campbell Scientific CR1000).

In contrast, the dial-up method delivers a gap-free data set, but its bi-polar behavior drives me nuts. There are periods when each scheduled call results in a connection and new data, but there are also periods when each scheduled call fails to connect. Over the last 4 months I made 1450 calls to Greenland. Only 189 of these 1450 calls resulted in a connection. That is a failure rate of 87%. It admittedly includes one desperate day (Sept.-18) when I made a call every 3 minutes and each call failed. This desperation was after a 10-day sequence of failed calls when I lost my cool. There were 86 out of 130 days when a successful connection was made, that’s still a large failure rate of 34%, but there are zero missing data so far. [The station was set up Aug.-20.]

Logs-OWS

The advantage of the fickle dial-up connection is that I only need one connection to recover all data that has been collected since the last successful call. This differs from the SBD text message, where a lost connection means lost data. Furthermore, the connection to the Greenland station is a regular RS-232 connection which acts the same as the iPhone connected to the computer from which I type these lines. Hence software changes are possible, too, as scary as they may be.

Now why is the Iridium connection acting in a such a bi-polar fashion, that is, working like a charm for weeks and months to suddenly shut down completely for days to weeks just as suddenly? My honest answer is that I do not know. Furthermore, nobody really knows for sure. There is some talk in hidden places that Iridium modems or phones “de-register” themselves from the Iridium network, if they do not start a phone call. This is no problem for the SBD message as the Greenland modem always does the calling. It does matter for my dial-up, because the Greenland modem never initiates a call, it only responds when called after the Greenland computer gives it the power to do so. Which brings me to

‘Fake call’
Register_Modem = “ATDT 1234″ & CHR(13) & CHR(10)
SerialOpen (ComRS232,19200,0,0,2000)
Delay (0,1,Sec)
SerialOut (ComRS232,Register_Modem,””,0,0)
SerialClose (ComRS232)

The “fake call” is a software update that tells the Greenland modem to, well, make a fake call. The text string Register_Modem contains a non-existing phone number (I hope) 1234 as well as a carriage return CHR(13) and a line feed CHR(10) and the string is send via SerialOut to the modem that is addressed here as ComRS232 after the serial port between Greenland computer and modem is opened via SerialOpen. Lets see how this works over the next days, weeks, and months. For the first time, I received this morning a response from Greenland that it was “BUSY.” I took this as a good sign …

PostScript: Data look awesome with new, large, and unexpected diurnal variations that started Dec.-8.

Ocean temperature (black) and salinity (red) below Petermann Gletscher from Dec.-6 (Day-340) through Dec.-31 (Day-365). Top panel is just below the glacier ice at 95-m below sea level while bottom panel shows data 810-m below sea level.

Ocean temperature (black) and salinity (red) below Petermann Gletscher from Dec.-6 (Day-340) through Dec.-31 (Day-365). Top panel is just below the glacier ice at 95-m below sea level while bottom panel shows data 810-m below sea level.

Below Petermann Glacier: The First 100 Days

I am still stunned to see data coming to me hourly from below a glacier in northern Greenland while I sip my breakfast coffee. Each and every day for the last 100 days I got my data fix from the Ocean Weather Station that was born 100 days ago. Every morning at 8:15 the station sends me data from 5 ocean sensors below the glacier. A year ago I did not even know that I would be going to northern Greenland with the Swedish icebreaker I/B Oden in the summer of 2015, never mind that we would be able to pull off the engineering challenge to set up the first and only ocean observing system of Greenland. Today, I am over-joyed to report, we got 100 days of data.

IMG_3029

University of Delaware PhD student Peter Washam at the Ocean-Weather station on Petermann Gletscher after final installation 2015-Aug.-20, 17:00 UTC at 80 39.9697 N and 60 29.7135 W.

It all started when a French PhD student approached me at a scientific meeting in San Francisco last December. Céline is a now a doctor of oceanography, but at the time she was not. At the meeting Dr. Céline Heuzé of the University of Gothenburg in Sweden asked me for data and insights on how the ocean circulation in Nares Strait worked, so that she could connect results from planned field work in northern Greenland to her science interests in the Labrador Sea more than 1000 miles to the south. She also introduced me to Dr. Anna Wåhlin and the three of us got very excited about Petermann Fjord, Sweden, and polar oceanography. Here we are in Sweden preparing and off Greenland working:

A few weeks prior the US government and Sweden had just agreed to work together on a joint expedition to Petermann Fjord in northern Greenland. Friends at Oregon State University needed a ship to collect data with which to reconstruct and understand changes of the land- sea-, and ice-scape of North Greenland during the last 10,000 to 50,000 years. They wanted to uncover where past glaciers were located and where sea level was at that time. For this, they needed many sediment cores from the adjacent ocean, fjord, and below the floating glacier. Today this glacier is as thick as the Empire State Building in Manhattan is high. The British Antarctic Survey (BAS) agreed to drill the holes, collect the sediment samples, and take a profile of ocean properties from below the glacier ice to the bottom of the ocean. They estimated it would take about 5 days to drill each hole. Our idea was to use these holes to keep sensors, computers, and satellite phones in place to collect hourly data into the future as long as possible … 100 days so far.

After the Dec.-2014 San Francisco meeting we decided to use these holes to measure ocean temperature, salinity, and pressure for as long as the batteries would last, about 3-4 years, but I had neither money, cables, data logging computers, nor satellite phones to do any of this, only the ocean sensors. When I told Keith Nicholls of BAS about the idea and my predicament, he said that he could find some computers and satellite phones from experiments he had done in Antarctica. I then said that I would organize cables, a weather station, and some funds to pay for it.

A crowd-funding experiment in February failed to generate funds, but NASA came to the rescue by opening a way to compete for the needed $60,000 to cover the cost of hardware, travel, and satellite phone charges. The funds allowed us to ship about 1200 pounds of gear from Delaware to Sweden where it had to be loaded onto the ship in May of 2015. We did not have much time to built the system and had no time left to test it. Two drums of cable arrived with only 5 hours to spare before the ship left Sweden in June for Greenland. We met the ship in Thule, Greenland in July.

Fast-forward to the 20th of August 2015 when our ocean observing system went into the salty ocean waters below Petermann Gletscher. The surface weather station with satellite connections was deployed 10 days earlier to test satellite communications and collect weather data for Oden’s extensive helicopter flight operations on and around the glacier. It included a rushed visit by a large team from CBS News 60 Minutes who were flown and shown all over the place. We last saw the station during 24 hours of day light on 27th August when we calibrated the wind sensors, but to me the daily satellite phone call of the station with new data is a sign of life from an ocean outpost that survived another day in the total darkness of the polar night. It draws energy from two car batteries that run even at the -36 degree Centigrade (-33 F).

AWS

First 100 days of ocean and weather observations from the University of Delaware Ocean Weather Station on Petermann Gletscher, Greenland. Panels show (from bottom to top) time series of 1. battery voltage, 2. ocean (red) and air (black) temperatures, 3. wind speed, 4. wind direction, 5. glacier movement, and 6. atmospheric pressure. Time is given in year-day, Nov.-28 is Day-332. The sun set on Day-290 or Oct.-17.

New data are posted at

http://ows.udel.edu

which over the next few weeks we will develop into a web-site to distribute the daily observations to everyone. I am most thankful to many of scientists, engineers, technicians, sailors, and women in England, Sweden, and the United States of America, but this Thanks-Giving weekend I am grateful to the men and women of a great nation that gave me a place to study, work, and live doing while exploring ocean and now glacier physics as well.

EDIT: I just discovered this 7 minute video on our expedition, credits go to Saskia Madlener at 77th Parallel Productions:

Sun Sets over Petermann Gletscher

Lights are out. Our ocean weather station on a floating glacier of northern Greenland confirms what the U.S. Naval Observatory reports for location 60 degrees and 30 minutes West longitude and 80 degrees and 40 minutes North latitude: As of today the sun is no longer above the horizon and will not rise until 23 February 2016. Total darkness means no solar power for the station that will have to survive on a fancy car battery temperatures as low as -50 degrees centigrade. Last week with the sun still up our station recorded -30.4 degrees celsius about 4 feet above the ice. How long will the station survive on that car battery?

Petermann Gletscher at dawn on 5 Oct. 2015 as captured by NASA Operation IceBridge. Our Ocean Weather Station is in the corner bottom left.

Petermann Gletscher at dawn on 5 Oct. 2015 as captured by NASA Operation IceBridge. Our Ocean Weather Station is in the corner bottom left.

Without power the station does not function, because each sensor, each computer, and each telephone call via the Iridium satellite system requires electricity. Without power I am in the dark about what the station does or what ocean or air temperatures are. Since I do have power at the moment, well, I got new data. For example, there is a voltage that the station sends me …

Voltage at Ocean Weather Station on Petermann Gletscher.

Voltage at Ocean Weather Station on Petermann Gletscher.

… whenever the sun is up, the solar panels recharge the battery and the voltage goes up. As I use electricity, the voltage goes down. Lets ignore a small temperature effect and details on how much electricity we draw at what “amperage.” Instead, lets focus on the regular up and down of voltage for the last 60 days and how it suddenly went flat. The flat line at 12.5 Volts tells me that the sun is down. The station now uses the car battery, but how long will this last? Quick answer is … a day, if I am dumb. Or 150 days, if I am smart. Time will tell, if I made a mistake in either my power budget or my computer code that gives and takes power to a range of sensors. Scary stuff, and my little sister Christina Parsons can attest, how nervous I was, when I uploaded new power-saving software that I wrote from my attic at home to the station in Greenland. The station did take the new software, restarted itself, and works making one data call each day instead of three. Data are still collected every hour, but I save 20% of total power.

Power is something in Watts (40 W Light bulb anyone?) and you have to multiply voltage by current draw (0.5 Amps anyone?) to estimate the power needs of the device drawing 0.5 Amp current at 12 Volts. Incidentally, 0.5 Amps is what the Iridium satellite phone draws when it calls me with new data. Let me check my power budget, if this is true … nope, it only takes 0.365 Amps, so it takes 12 volts times 0.365 Amps equal 4.4 Watts which is about 1/10 of that 40 W light bulb you are looking at, perhaps, or the station we put up: the yellow box is the car battery powering all the gadgets you see and many more you do not:

What I just showed you is the beginning of a power budget that I had to make to get my station through the night, now that there is no more sun for the next 4-5 months. My car batteries are rated to give 110 Watts for an hour, so if I run my 4.4 W satellite phone all the time, I would be out of battery juice after 110 Watt-Hours divided by 4.4 Watts equals 25 hours. That’s bad, real bad, especially since one should not run a car battery to zero and the battery at -30 degrees Celsius may only give me half the power than it would at the more usual 15 degrees Celsius we got outside. The solution to this problem is to use the phone only for a few minutes each day, say 5 minutes. So, since I am using the phone only 5 minutes out of the 1440 minutes that each day has, it takes about 1440 minutes divided by 5 minutes times 25 hours equals 300 days for the phone running 5 minutes each day to run down the battery. Magic this math is not, but it shows how important it is to use resources (electricity) wisely. There are times and places where it is not possible to plug your iPhone into a power outlet. You get the picture … well, here are some that University of Delaware PhD student Peter Washam took who was part of the ice drilling team during last summer’s deployment of the ocean weather station:

So, as of this morning at 4 am Delaware time, the station now in total darkness tells me that the ocean temperatures 700 meters below the 100 meter thick glacier are +0.3 degrees Celsius while air temperatures 2 meters above the ice are -11.1 degrees Celsius. Now what that means to the melting of the glacier by the ocean, I will have to tell you at another time in more detail. These data are the ONLY data from below any glacier to the north of the equator. We are really breaking new ground and are making new discoveries as we go along … as long as there is power. Hopefully there is no dumb mistake in my power budget.

Sun over the horizon of Greenland as seen during NASA's Operation IceBridge Flight in October 2015.

Sun over the horizon of Greenland as seen during NASA’s Operation IceBridge Flight in October 2015.