Tag Archives: data

Ghosts of Discovery Harbor: Digging for Data

Death by starvation, drowning, and execution was the fate of 19 members of the US Army’s Lady Franklin Bay Expedition that was charged in 1881 to explore the northern reaches of the American continent. Only six members returned alive, however, they carried papers of tidal observations that they had made at Discovery Harbor at almost 82 N latitude, less than 1000 miles from the North Pole. Air temperatures were a constant -40 (Fahrenheit or Celsius) in January and February. While I knew and wrote of this most deadly of all Arctic expeditions, only 2 days ago did I discover a brief 1887 report in Science that a year-long record of hourly tidal observations exist. How to find these long forgotten data?

My first step was to search for the author of the Science paper entitled “Tidal observations of the Greely Expedition.” Mr. Alex S. Christie was the Chief of the Tidal Division of the US Coast and Geodedic Survey. He received a copy of the data from Lt. Greely. His activity report dated June 30, 1887 confirms receipt and processing of the data, but he laments about “deficient computer power” and requests “two computers of standard ability preferable by young men of 16 to 20 years.” Times and language have changed: In 1887 a computers was a man hired to crunch numbers with pen and paper.

Data table of 15 days of hourly tidal sea level observations extracted from Greely (1888).

Data table of 15 days of hourly tidal sea level observations extracted from Greely (1888).

While somewhat interesting, I still had to find the real data shown above, but further google searches of the original data got me to the Explorer’s Club in New York City where in 2003 a professional archivist, Clare Flemming, arranged and described the “Collection of the Lady Franklin Bay Expedition 1881-1884.” This most instructive 46 page document lists the entire collection of materials including Series III “Official Research” that consists of 69 folders in 4 Boxes. Box-4 File-15 lists “Manuscript spreadsheet on Tides, paginated. Published in Greely (1888), 2:651-662” as well as 3 unpublished files on tides and tide gauges. With this reference, I did find the official 1888 “Report on the United States Expedition to Lady Franklin Bay” of the Government Printing Office as digitized from microfiche as

https://archive.org/details/cihm_29328

which on page 641 shows the above table. There are 19 more tables like it, but at the moment I have digitized only the first one. Unlike my colleagues at the US Coast and Geodedic Survey in 1887, I do have enough computer power to graph and process these 15 days of data in mere seconds, e.g.,

Hourly tidal observations at Discovery Harbor taken for 15 days by Greely in 1881 and Peary in 1909.

Hourly tidal observations at Discovery Harbor taken for 15 days by Greely in 1881 and Peary in 1909.

A more technical “harmonic” analyses reveals that Greely’s 1881 (or Peary’s 1909) measured tides at Discovery Harbor have amplitudes of about 0.52 m (0.59) for the dominant semi-diurnal and 0.07 m (0.12) for the dominant diurnal oscillation. My own estimates from a 9 year 2003 to 2012 record gives 0.59 and 0.07 m for semi-diurnal and diurnal components. This gives me confidence, that both the 1881 and 1909 data are good, just have a quick look at 1 of the 9 years of data I collected:

Tidal sea level data from a pressure sensor placed in Discovery Harbor in 2003. Each row is 2 month of data starting at the top (August 2003) and ending at the bottom (July 2004).

Tidal sea level data from a pressure sensor placed in Discovery Harbor in 2003. Each row is 2 month of data starting at the top (August 2003) and ending at the bottom (July 2004).

There is more to this story. For example, what happened to the complete and original data recordings? Recall that Greely left Discovery Harbor late in the fall of 1883 after supply ships failed to reach his northerly location two years in a row. This fateful southward retreat from a well supplied base at Fort Conger and Discovery Harbor killed 19 men. Unlike ghostly Cape Sabine where most of the men perished, Discovery Harbor had both local coal reserves and musk ox in the nearby hills that could have provided heat, energy, and food for many years.

It amazes me, that a 1-year copy of tidal data survived the death march of Greely’s party. It took another 18 years for the complete and original records to be recovered by Robert Peary who handed them to the Peary Arctic Club which in 1905 morphed into Explorer’s Club of New York City. I suspect (but do not know), that these archives contain another 2 years of data that nobody but Edward Israel in 1882/83 and the archivist in 2003 laid eyes on. Sergeant Edward Israel was the astronomer who collected the original tidal data. He perished at Cape Sabine on May 29, 1884, 25 years of age.

Edmund Israel, astronomer of the Lady Franklin Bay Expedition of 1881-1884.

Edmund Israel, astronomer of the Lady Franklin Bay Expedition of 1881-1884.

References:

Christie, A.S., 1887: Tidal Observations of the Greely Expedition, Science, 9 (214), 246-249.

Greely, A.W., 1888: Report on the Proceedings of the United States Expedition to Lady Franklin Bay, Grinnell Land, Government Printing Office, Washington, DC.

Guttridge, L., 2000: The ghosts of Cape Sabine, Penguin-Putnam, New York, NY, 354pp.

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.