IIIF Color HighRes
National Institute of Informatics - Digital Silk Road Project
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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.4 |
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Citation Information
•
ICE AND SOUNDINGS IN THE TSO-NGOMBO. 299
the last sounding there still remained three or four hundred meters to the southern shore.
In every alternate hole, beginning with the second from the north, I measured the temperature of the water at different depths, namely at four levels in the vertical line, that is to say at 5, at 10, at 15 m., and at the lake bottom. The annexed section (fig. 203) shows the result of these measurements. At each and every one
| Fig. 2 03 . 3.69 1 8.19 2 0.00 20.45 | 2I.39 21.55 20.00 | 17.45 = depth. |
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| 2.6o 2.70 | 2.82 | 3.01 |
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| 2.95 2.91 3.21 3.22 | 3.27 3.30 | 3'48 3.60 | degrees Celsius. |
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| 3.09 3.29 | 3.38 | 3.59 |
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| Breadth = 137 5 + about 50o m. | Horizontal scale = 1 : | 10,000. Vertical scale = 1 : | 1,000. | |
of the stations the temperature rose at each successive depth as we travelled from north to south: thus at 15 m. depth it was 3.21°, 3.22°, 3 30°, and 3.60. Each isotherm shows therefore an upward curve, the vertex of which came immediately underneath the long lane of open water, though this by no means coincides with the greatest depth of the lake, but lies, I dare say, over a depth of 14 to I5 m. At each of the temperature stations the temperature increased uniformly towards the bottom; though there was a slight departure from uniformity observable at the first, where the temperatures read 2.60°, 2.95°, 3.21° and 3.09°. This irregularity may have been caused by chance currents, which must of course exist in a lake at the bottom of which such a relatively large number of warm springs break out. Along the northern side of the lake the water was clearly flowing west, at any rate it was doing so just underneath the ice, as was evident from the direction of the stalks of the vegetation that were frozen fast in the under side of the ice or hung down into the water; they all pointed (see fig. 204) in that direction. And indeed it must of necessity be so, for the Tso-ngombo empties itself through a sound into the Panggong-tso ; nevertheless the movement of current indicated by the vegetation is, I have no doubt, a local phenomenon occasioned by springs. At the first temperature station we found a warmer layer of water 3.21° between two somewhat colder layers, namely 2.95° and 3,09°. Upon comparing this station with the last one, we see that, whereas the temperature 3.10° occurs in the former at a depth of 18 m., in the latter it is found at 6 m. depth. Anyway the
arrangement of the isotherms makes it ;' i -- 2• J
conceivable that warm springs issue at ~~
the bottom of the lake precisely under the ~.~~~
open lane near the middle. South of that ~=
the isotherms ought to dip down again, in — the way shown in the sketch, towards the
subaqueous slope of the southern shore. Fig. 204.
~
~~~ ~ ~ ~.
~,
North.
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