Actinometric Observations and Sunshine Duration in Tomsk
Abstract Generated abstract
This paper reports actinometric and heliographic observations made in Tomsk, combining winter 1910 measurements with earlier data from 1901 and sunshine records from 1911 to 1914. Atmospheric transparency coefficients were calculated by least squares for different solar altitudes, and four years of Velichko heliograph observations were summarized by month and hour to estimate sunshine duration, clear and overcast days, and solar heat received on a horizontal surface. The results indicate strong seasonal variation in sunshine, an annual actual solar heat total of 58.5 large calories per square centimeter after accounting for cloudiness, and a somewhat higher annual heat receipt in Tomsk than at comparable Western European latitudes.
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V. D. Dudetskii
Actinometric Observations and Duration of Sunshine in Tomsk
In the winter of 1910, the author and A. V. Ignat'ev (†) carried out a series of observations with a Violle–Savel'ev actinometer in Tomsk. These observations supplement the observations of D. A. Smirnov in the spring and autumn of 1901.
From the longest series of observations by the author and A. V. Ignat'ev on February 1, 2, and 3, 1910,*) the coefficient \(p\) of atmospheric transparency was computed by the method of least squares. Depending on the altitude of the sun, the coefficient \(p\) was found to be different: for the air mass \(M\) traversed by the ray, \(M > 6.6\), \(p = 0.91\); for \(4.5 < M < 6.6\), \(p = 0.87\); and for \(M < 4.5\), \(p = 0.85\). According to D. A. Smirnov’s data, for \(1.3 < M < 1.5\) one obtains \(p = 0.74\).
In addition to these observations, a series of determinations of radiation at noon was carried out. The results are not given here for lack of space.
Sunshine was recorded with a Velichko heliograph installed on the tower of the physical laboratory of the Technological Institute. Complete years of observations, 1911–1914, were processed and summarized. Table I presents, averaged over four years, the distribution of the duration of sunshine by hours of the day for all months of the year. This duration is expressed in hours and tenths of an hour for the whole month, in the corresponding hour. The last column gives the percentage ratio of the actual sunshine to the possible sunshine.
Table I.
| Months | 4–5 | 5–6 | 6–7 | 7–8 | 8–9 | 9–10 | 10–11 | 11–12 | 12–13 | 13–14 | 14–15 | 15–16 | 16–17 | 17–18 | 18–19 | 19–20 | Sum | % |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I. | — | — | — | — | 0.0 | 1.2 | 2.9 | 4.4 | 4.3 | 3.6 | 1.6 | 0.0 | — | — | — | — | 18.0 | 25 |
| II. | — | — | — | 0.0 | 1.3 | 3.3 | 4.9 | 5.7 | 5.9 | 5.5 | 4.2 | 1.7 | 0.2 | — | — | — | 32.7 | 35 |
| III. | — | — | 0.3 | 2.3 | 4.5 | 5.5 | 6.0 | 6.2 | 6.0 | 6.0 | 5.4 | 4.5 | 2.7 | 0.7 | — | — | 49.6 | 48 |
| IV. | — | 0.5 | 3.5 | 4.7 | 5.4 | 5.8 | 5.9 | 5.9 | 5.8 | 5.6 | 5.8 | 4.7 | 4.9 | 3.4 | 0.8 | — | 64.1 | 46 |
| V. | 0.0 | 0.3 | 4.9 | 6.1 | 6.2 | 6.3 | 6.6 | 6.6 | 6.6 | 5.9 | 5.8 | 5.4 | 5.5 | 4.7 | 2.8 | 0.0 | 75.9 | 47 |
| VI. | 0.8 | 4.4 | 5.4 | 5.7 | 6.3 | 6.5 | 6.4 | 6.4 | 6.3 | 6.4 | 6.1 | 6.0 | 5.4 | 4.9 | 3.9 | 1.3 | 88.3 | 48 |
| VII. | 0.5 | 3.6 | 5.4 | 5.9 | 6.6 | 6.7 | 6.7 | 6.7 | 6.2 | 6.0 | 5.6 | 5.5 | 5.9 | 5.3 | 3.4 | 0.8 | 81.0 | 48 |
| VIII. | 0.0 | 0.9 | 3.3 | 4.3 | 4.9 | 4.9 | 4.8 | 5.0 | 4.9 | 4.6 | 4.3 | 4.0 | 3.7 | 3.2 | 1.2 | 0.0 | 54.0 | 36 |
| IX. | — | 0.1 | 1.3 | 2.7 | 3.8 | 4.4 | 5.0 | 5.3 | 4.9 | 4.7 | 4.4 | 4.3 | 3.9 | 2.7 | 0.5 | — | 48.0 | 38 |
| X. | — | — | — | 0.9 | 2.6 | 3.1 | 3.5 | 3.6 | 3.6 | 3.2 | 3.2 | 2.7 | 1.1 | — | — | — | 27.4 | 27 |
| XI. | — | — | — | 0.1 | 0.1 | 0.1 | 1.8 | 2.4 | 2.5 | 2.5 | 2.1 | 1.5 | 0.2 | — | — | — | 12.9 | 16 |
| XII. | — | — | — | — | 0.0 | 0.2 | 1.2 | 1.9 | 2.2 | 1.8 | 0.4 | 0.0 | — | — | — | — | 7.6 | 11 |
| Average | 0.3 | 2.0 | 3.4 | 3.3 | 3.5 | 4.0 | 4.6 | 5.0 | 5.0 | 4.6 | 4.1 | 3.4 | 3.3 | 3.6 | 2.1 | 0.5 | 52.8 | 35 |
Counting as clear those days when sunshine amounted to no less than 80% of the possible duration, and as overcast those when it was no more than 20%, I compiled a table of the number of clear and overcast days by months.
*) Printed in full in Izv. Sib. Sel'sk. Khoz. Akademii for 1923.
Table II.
| Month | I. | II. | III. | IV. | V. | VI. | VII. | VIII. | IX. | X. | XI. | XII. | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clear | 0.8 | 2.0 | 5.2 | 6.0 | 3.5 | 2.8 | 2.8 | 1.5 | 3.0 | 2.5 | 0.2 | 0.0 | 30 |
| Overcast | 17.0 | 9.7 | 10.2 | 8.5 | 6.7 | 4.7 | 4.0 | 8.5 | 8.7 | 17.0 | 20.7 | 23.2 | 139 |
Having at our disposal the solar radiation and the coefficient of transparency of the air from our observations and Smirnov’s observations for different seasons of the year, and knowing the average duration of sunshine, one can calculate the sum \(S\) of large calories received from the sun by one square centimeter of a horizontal surface during a month, if there were no clouds, and the actual sum \(S'\) of heat as it is obtained if the actual duration of sunshine is taken into account.
Table III.
| Month | I. | II. | III. | IV. | V. | VI. | VII. | VIII. | IX. | X. | XI. | XII. | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| \(S\) | 1.6 | 4.0 | 8.0 | 13.0 | 17.0 | 18.4 | 17.2 | 14.1 | 9.5 | 5.0 | 2.0 | 0.9 | 110.7 |
| \(S'\) | 0.6 | 1.9 | 4.3 | 7.1 | 10.0 | 11.2 | 10.2 | 6.8 | 4.3 | 1.7 | 0.4 | 0.1 | 58.5 |
Comparing these numbers with the data for stations of Western Europe at the latitude of Tomsk, one can see that in Tomsk the quantity of heat falling on a horizontal surface is somewhat (about 8%) greater than in Europe.
Stud. E. A. Bessonov
I. Investigation of the Ice of the Tom River before the Ice Drift of 1914 (abstract).
The investigation was carried out in the same manner as in 1911 and 1912 (B. P. Weinberg, Izv. Tomsk. Tekhn. Inst., 29, 1913, pp. 7+7) and in 1913 (E. A. Bessonov, Izv. Tomsk. Tekhn. Inst., 35, 1914, 6 pp.). Six blocks of ice were studied; one of them (No. 5) was taken at a place on the Tom River where the water of the Ushaika River had free access. The results are expressed in five tables with numerous notes characterizing the individual specimens and the special features of the experiments. The 1st and 2nd tables correspond, in content and arrangement, to Tables I and II of the 1914 article; the 3rd gives the results of testing for fracture a series of pieces cut in various directions from one and the same horizontal layer; the 4th and 5th give the results of a detailed investigation of the density and resistance to fracture of a series of small blocks cut from block No. 5. In abbreviated form these tables give