Wednesday, December 2, 2015

Databases Galore - 11

Fig. 1 The zones are back
The scientists I deal with in Dredd Blog posts have indicated that it is time to watch the ice shelves: "as goes the ice shelf so goes the ice stream flow in the ice sheet" (Watch The Ice Shelves).

In addition to that, they tell me that in order to watch the ice shelves, one has to watch the water flow underneath them, because in the main they are melting from below.

That means watching the water temperatures down fairly deep.

So, I found a database that has subsurface water temperature records.

Notice the following comment:
NB: While you are perfectly at liberty to download the whole database for your own research, please make a note of the version and note that corrections, additions, and re-calibrations are all on-going. Much of the data was typed in by hand, and so many errors probably remain.

The whole database can be downloaded from this link (3MB). The format is fixed width:

%7.2f%6.2f%2d%4d%5d%6.2f%6.2f%6.2f%6.1f%15s%60s

with longitude, latitude, month, year, depth (m), temperature (C), salinity (psu), d18O, dD, notes, reference.
(GISS data site). Ok, so I downloaded it, configured it for an SQL database, and placed 25,514 records in the database table.

I also resurrected the old Zone code, because this is a good place to use zones since their data is latitude / longitude specific as you can see by the column / field names: "longitude, latitude, month, year, depth (m), temperature (C), salinity (psu), d18O, dD, notes, reference".

They don't give a reference to a country, island, ice sheet, etc. in the data, so I wrote a module and ran through it.

I am marking each record with a zone designation (Fig. 1, cf. New Type of SLC Detection Model - 2).

The sea level change (SLC) business did not fit well with those 36 zones, but this subsurface temperature database will.

I have already identified from this GISS data that it contains places where there are no PSMSL tide gauge stations.

So far, I have noticed that some of them are located at or near Antarctica coastal areas (zones bk - bp), where it would be important to know the subsurface water temperature over time.

I wrote a module to scan the data to determine records for each zone area:
zone [0, aa] = 2358
zone [1, ab] = 3022
zone [2, ac] = 1333
zone [3, ad] = 1857
zone [4, ae] = 2016
zone [5, af] = 1404
zone [6, ag] = 875
zone [7, ah] = 1749
zone [8, ai] = 1
zone [9, aj] = 1448
zone [10, ak] = 161
zone [11, al] = 649
zone [12, am] = 643
zone [13, an] = 43
zone [14, ao] = 399
zone [15, ap] = 276
zone [16, aq] = 132
zone [17, ar] = 474
zone [18, ba] = 120
zone [19, bb] = 198
zone [20, bc] = 58
zone [21, bd] = 18
zone [22, be] = 45
zone [23, bf] = 81
zone [24, bg] = 459
zone [25, bh] = 1069
zone [26, bi] = 268
zone [27, bj] = 26
zone [28, bk] = 103
zone [29, bl] = 28
*zone [30, bm] = 1807
*zone [31, bn] = 363
*zone [32, bo] = 260
*zone [33, bp] = 588
*zone [34, bq] = 1
*zone [35, br] = 334

* = Antarctica

not found = 0
found = 24666
There are 25,514 total rows, 848 rows had years with a zero value, so only 24,666 were usable to begin with.

We can learn about temperatures at useful depths, since the readings go deep (>1000 m).

This may be especially useful for knowing the temperature of water that flows underneath the ice shelves driven by various currents.

So, I will be perfecting that system and reporting about it once I have a complete handle on it.

The next post in this series is here, the previous post in this series is here.




A discussion about ice shelves vs. ice sheets:

15:29 when the ice shelf "Larsen A" collapsed the entire glacier's flow speed toward the sea increased ...
18:50 "Larsen B" ice shelf collapse caused the same thing ... the entire glacier's flow accelerated toward the sea ...
19:30 when the ice shelf goes away so does the restraint on the glacier, and they then move faster, 8 times faster, toward the sea
27:15 the East Antarctica Totten Glacier basin contains about as much ice as all of Western Antarctica, and it is destabilizing
30:30 the condition of the ice shelf controls what happens to the ice sheet




2 comments:

  1. New Scientist says current El Nino is the worst ever (link).

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  2. Yep, i saw that Randy - now it's "official."

    Great advancement here, Dredd! That will really help tell the story, and i believe that the fact that we now know that this el Nino is indicating the warmest water ever in the oceans (and where will it go from here but even higher next time), that over time this warmth will find it's way to the poles and continue wreaking havoc.

    Tom

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