Hideki NARITA

Tomomi YAMADA

ナリタ ヒデキ

ヤマダ トモミ

National Institute of Polar Research Repository

IV. DRIFTING SNOW AT SYOWA STATION AND MIZUHO CAMP IN 1971 - 1972 Tomomi YAMADA* and Hideki NARIT A* 1. Drifting Snow at Syowa Station in 1971 (Observer: T . Yamada) An observation site was located on a sea ice, about 200m in the north­east of Syowa Station, where the sea ice was covered by a flat snow cover. Two parallel trenches (2 . Sm long, 1. Sm wide and 60 cm deep for each) were excavated at the snow surface, so that their long axes were perpendicular to the wind direction and a distance between them along the wind direction was 1 m, as shown in Fig .1. Kobayashi (1972) pointed out the collection factor of a trench in such a size for low -drifting snow as 1.0 for a wind slower than 7 m/ s, and O. 8 - 0. 9 for a wind faster than that. Snow drifting rate (g/ cm· min: amount of drifting snow through a vertical plane with unit width perpendicular to the wind direction, per unit time) was calculated from the amount of captured snow in the windward trench during a certain time period, as it was observed that the collection factor of the windward trench was considerably close to 1 .0 even by a wind of 11 m/ s. The result of the observation is given in Table 1. 2. Drifting Snow at Mizuho Camp in 1971 (Observer: T. Yamada) Two kinds of cyclone-type drift collectors (Fig. 2) were used to measure the mass flux of drifting snow (g/ cm2. min: amount of drifting snow through unit area, perpendicular to the wind direction at a certain height from the snow surface, per unit time). The inner diameter of the inlet tube of the type-1 and the type-2 drift collector w_as 3 cm and 2 cm, respectively, and the collection factor was estimated as 0.6 for both (Naruse, 1970). The observation area was selected so that it was fairly flat and smooth (without big sastrugis and snow dunes) for a wide extension. Several drift collectors were set at different heights from the snow surface. Measurements were made when the direction and speed of wind were fairly constant. The result of the observation is given in Table 2. * The Institute of Low Temperature Science, Hokkaido University, Sapporo. -106 3. Wind Speed and Air Temperature in 1971 The wind speed· and air temperature were measured as important parameters of snow drifting, during the drift observation at the following locations and heights: Location and height at which (A) wind Snow drift observation site speed and CB) air temperature were measured Location Height Syowa Station 200m NE of Syowa Station A: 10m above the groun (14. Sm above B: 1. Sm above the area Syowa Station sea level) ground d Mizuho Camp 30 m ENE of by the observa - A: 4 .Sm above the snow area Mizuho Camp tion site surface B: 1. 8m above the snow surface The result is given in Tables 1 and 2. 4. Drifting Snow at Mizuho Camp in 1972 (Ovserver: H. Narita) A box-type drift gauge (a combination of 10 small cabinets in a series, as shown in Fig.3: Kobayashi, 1972) was placed at the snow surface so that the upper side (open side) of the cabinets was properly level with the surround­ing snow surface without a gap between the gauge and snow, whereby the lengthwise side of the gauge was directed in parallel to the wind direction. The amount of drifting snow captured in each cabinet was weighed, and the drifting rate Q (g/ cm· sec), the average saltation length [ (cm), and the rebounding mass of drifting snow G (g/ cm2 , sec) were calculated as follows: the x -axis was taken in parallel to the wind direction with the origin at the windward edge of the gauge, as shown in Fig. 3; then the amount of drifted snow F(x) is given as, F (x) = G { 100 g(l)dl - lx g(l)dl} G { 1 -( g(l)cll}' -107-(1) where F(x) G amount of drifted snow onto a unit area (g/ cm2. sec), the center of which is located at x, rebounding mass of drifting snow, G = F(x)x=o (g/ cm2. sec), 1 saltation length of a snow particle (cm), g(l) distribution function of saltation length. The amount of drifting snow Q is given as, Q = 1·F(x) dx = L·G, where Q L mass of drifting snow which passes through a unit width perpendicular to the wind direction in a unit time (g/ cm. sec), mean length of saltation of drifting snow particles (cm), (L and G are functions of wind velocity, respectively.) The wind velocity was measured at a level of lm above the snow surface. The result is given in Table 3. References Kobayashi, D .(1972): Studies of snow transport in low-level drifting snow. Contr. Inst. Low Temp. Sci., Ser. A, 24, 1-58. Naruse, R .(1970): Measurement of drifting snow on the coastal region of Antarctica, near Syowa Station. Low Temp. Sci., Ser. A, 28. 147-153 (in Japanese). m, I t 1_0:,-1.5�, ..... 0. 1.5-'I _L prevailing .Edd" t· win ,rec ,on Fig. 1 . Trenches for measuring drift rate of snow, in Syowa Station area. -108 -Date 24 Aug. 25 Aug. 26 Aug -12--+ unit:cm �2-+-� Type-1 Type-2 Fig. 2. Cyclone-type drift collectors (from Naruse, 1970). "' r,,, X • Q WIND •• , I > x '•. F<x> . ..Ii 100 cm • , �,/r . •  �  ·10cm : : · : I : l I : : : . I , ,,., ' l I I : I I I I I I I I,, i. •• •-'• •- - ., ·- - .I• • - .L • • _ _, - • • ..I.• - -' - - • .i.. • - L • ••-" Fig. 3. Box-type drift gauge. Table 1. Measurement of drifting snow by a trench method at Syowa Station in 1971. Level of snow surface Time Mean w:ilrl Mean air Amount of s peed temperature snowdrift Drift rate from to (min) (m/ s ec) (OC) (f}../ cm) 12./cm.min) 1130 1230 60 10.0 -12.2 427 7.1 1233 1427 114 11.0 -12.0 718 6.3 1432 1548 76 11.0 -11.6 824 10.8 1618 1716 58 11.5 -11.0 864 14.9 1724 1750 26 11.0 -11.2 160 6.2 1116 1200 44 11.2 -10.5 276 6.3 1408 1440 32 11.0 -9.6 278 8.7 1457 1538 41 9.9 -11.5 369 9.0 1546 1622 36 10.5 -12.0 274 7.6 1628 1706 38 8.0 -13.0 204 5.4 1002 1050 48 9.3 -17.1 293 6.1 1056 1136 40 10.7 -17.5 642 16.1 1143 1222 39 9.0 -17.2 312 8.0 -109 -Table 2. Measurement of drifting snow by cyclone-type drift collectors at Mizuho Camp in 1971. ( Level of collector was measured from the snow surface ) Time Mean wind Mean air Drift collector Mass flux Date speed temperature Level (g/cm2 -minxl0- 2) from to (min) (rrvs ) ( °C) TYpe (cm) Nov- 21 1500 1 7 1 0 130 1 5 -2 1.5 I 1 1 4 5.3 3 I 42 7.1 0 2 42 8.4 9 2 7 5 2.4 1 1 1 1 8 0.29 2 150 0.4 1 1845 2000 7 5 1 6 -2 2.0 1 1 1 84.0 I 1 42 2 2.7 7 1 1 1 8 6.0 4 Nov- 22 1205 1320 7 5 1 7 -1 6.0 1 4 117.86 I 9 64.20 1 20 2 9.91 2 60 61.5 7 2 1 3 3 29.7 9 1420 1520 60 1 7 -1 5.5 1 1 3 9 5.4 2 1 2 1 3 1.6 1 1 36 23.8 7 2 65 3 6.00 2 1 3 5 106.0 7 1635 1 7 4 5 70 1 7 - 1 5.8 1 9 91.1 9 1 2 1 3 5.4 5 1 37 2 2.4 7 2 37 51.4 9 2 68 3 3.6 7 2 1 3 5 13.27 Nov, 23 1330 1403 33 1 7 -1 4.7 1 5 2 5 1.6 3 1 1 3 3 7 5.3 0 1 34 1 0 1.5 1 2 34 136.7 2 2 64 3 8.1 2 2 1 3 8 13.99 I 5 1 0 1540 30 1 6 -1 4.7 I 5 4 4 2.7 1 1 I 3 2 5 8.7 9 1 3 4 9 3.5 8 2 3 5 1 8 5.4 2 - 110 -Time Mean wind Mean air Drift coll ector Mass fl ux Date speed temperature Level from to (min) (m/s) ( °C) TYpe (cm) ( g/cm2 •min x 10-2) Nov- 23 2 62 2 9.5 5 2 I 3 7 9.7 3 1 61 7 1633 1 6 1 5 -15.0 1 8 4 0 1.7 8 1 6 1 7 1644 30 1 5 -1 5.0 1 1 6 l 6 3.0 1 1 35 7 1.7 1 1 34 113.76 2 62 3 3.09 2 1 3 7 8.6 7 l 7 3 7 1758 21 1 8 -1 6.3 1 7 4 20.9 2 1737 1807 30 1 8 -I 6.3 I 1 5 237.79 1 36 8 2.88 1 36 115.36 2 62 5 3.7 9 2 I 3 7 I 8.7 5 1833 1850 1 7 1 8 -1 7.0 1 7 527.46 1833 1903 30 1 8 -1 7.0 1 l 5 2 30.4 8 1 36 9 0.1 2 1 36 103.6 8 2 62 4 5.8 2 2 137 9.5 5 Nov- 24 0938 1039 6 1 1 2 -1 5.3 1 9 1 3 2.4 9 1 l 9 23.36 1 36 4.8 3 2 37 6.3 5 2 62 2.5 2 2 I 3 7 0.4 4 1 1 1 2 1 1 5 7 45 I 3 -1 3.8 I 9 2 I 0.5 3 1 1 7 3 7.6 9 1 36 7.2 3 Dec. 9 1650 1754 64 9 -1 6.0 I I 0 1 3.6 4 I I 8 5.1 6 I 40 2.5 1 2 40 7.3 8 2 72 4.2 3 2 I 4 7 3.9 8 -111 -Time Mean wind Mean air Drift collector M ass flux Date · speed temperature Level (g/cm2 • minx 10-2) from to (min) (m/s) ("c) TYJ>e (cm) Dec. 18 1525 1625 60 11 - 10.1 1 1 0 166.5 9 1 1 5 5 7.80 1 38 2.9 1 2 38 2.9 2 2 75 0.53 2 1 5 0 0.0 9 170 1 180 1 60 1 2 -1 l.3 1 10 1 5 4.4 0 1 1 5 9 1.8 5 1 39 3.7 7 2 39 3.80 2 75 0.80 2 150 -Dec, 27 1 22 5 1325 60 1 3 -11.5 1 6 2 0 4.6 9 1 1 5 14 6.8 9 1 39 9.24 2 39 13.27 2 78 2.2 1 2 144 1.2 4 1400 1500 60 1 3 -10.3 1 5 166.1 2 1 1 5 8 2.61 1 39 6.0 5 2 38 16.90 2 78 l.9 5 2 1 5 3 3.18 1540 1640 60 1 0 - I 0.1 1 9 50.4 0 1 1 5 16.51 1 39 0.8 6 2 38 0.2 7 2 78 -2 153 0.44 -112-I No. Date 1 May 30 2 30 3 31 4 31 5 June 2 6 2 7 3 8 3 9 6 10 6 l 1 7 14 1 2 1 5 1 2 18 14 20 17 21 1 7 24 30 25 30 26 30 27 July l 28 1 Table 3. Measurement of drifting snow by a box-type drift gauge at Mizuho Camp in 1972. State of Wind Tern- Mass of deposited snow in each box (g) Total Dura- Drift velocity perature amount t ion rate snow of snow Rebound mass surface (rn/sec) ( ·c ) 1 2 3 4 5 6 7 8 9 1 0 drift (g) (sec) (g/cm-s) (xl0- 2g/cm2 •s) Dune 9.8 " 10.9 " 10.2 Sastrugi 10.6 Dune 11.1 " 10.6 " 11.3 Sastrugi 11.6 Dune 11.8 " 11.3 Sastrugi 14.5 Dune l 0.5 " 10.2 Sastrugi 12.0 Dune 7.6 ,, 8.0 " 8.4 Sastrugi 78 " 7 0  " 72 " 7 8  - 54.0 359.8 - 54.5 402.0 - 53.0 352.1 - 54.0 4.6 - 48.7 420.2 - 48.6 381.6 - 50.5 426.3 - 50.0 16.8 - 37. 5 426.3 - 37.5 464.2 - 33.0 17. 3 - 45.5 326.5 - 45.5 274.9 - 52.0 9.8 - 372 40.1 - 38.2 41.6 -40.51297.9 - 41.0 43.2 -40.5 15.0 - 46 7 28.7 - 470 27.9, 174.3 114.0 102.5 64.5 197.0 97.8 68.8 52.8 123.3 63.5 37.4 30.5 3.1 3.0 3.4 4.2 1 73.1 100.6 57. 5 37.4 110.9 68.2 46.4 43.0 1 75.2 101.6 71.3 54.6 1 7.1 16.8 16.5 16.3 214.3 115. 7 78.6 58.7 202.2 130.7 89.0 72.5 19.1 18.l 19.2 1 7.7 116.4 78.1 55.8 52.1 161.1 96.3 60.3 47.9 8.8 13.6 12.3 13.3 20.9 14.5 8.0 6.5 30.4 19.4 12.6 9.4 76.7 33.0 18.0 10.8 43 7 32.9 27.4 20.0 14.7 12.7 10.1 8.1 20.9 22.1 17. 6  1 3.7 26.8 25.6 18.5 18.4 62.4 60.5 5 6.9 53.5 55.8 1104.2 60 109.2 2,99 39.8 39.8 37.3 26.9 28 990.2 60 89.1 3.55 22.3 19.4 19.2 24.6 24.7 717.0 60 61.8 2.93 3.9 4.8 4.7 5.4 4.7 41.8 60 3.8 0.05 28.0 24.5 20.l 20.1 21.6 903.1 60 78.9 3.50 33.6 31.6 30.9 31.6 58.6 836.4 60 72.4 3.18 41.1 44.9 46.7 37. 7 34.7 1034.1 60 94.4 3.55 13.5 14.7 13.7 12.4 13.9 151.7 60 13.0 0.14 52.4 37. 7 35.0 3 9.5 48.5 1106.7 60 100.9 3.55 55.7 59.4 49.6 49.1 57.7 1230.1 60 108.2 3.87 15.4 21.0 20.4 22.6 24.6 195.4 60 8.1 0.07 49.2 42.9 40.8 35.0 36.9 833.7 60 80.3 2.72 41.6 45.7 35.4 28.6 25.1 845.3 60 75.8 2.29 13.4 13.6 12.8 15.8 12.1 125.5 60 10.3 0.08 5.3 4.4 3.1 3.7 3.6 110. l 120 4.9 0.18 7. 8 6.3 8.0 6.7 6.0 148.2 120 6.5 0.17 7. 4 4.7 3.5 2.7 2.1 456.8 120 l 9. 1 1.24 16.2 11.4 10.4 8.1 7.0 220.1 120 9.9 0.18 7.0 5.2 4.2 3.6 2.9 83.5 120 3.4 0.06 11.5 10.1 7. 6 6.6 6.0 144.8 120 13.7 0.24 14.7 12.8 10.4 9.4 j 8.8 1 73.3 120 16.6 0.23 29 2 Dune 6.8 - 53.5 161.4 42.6 27. 8 7.0 4.7 3.2 2.7 - 1.6 1.4 252.4 120 9.4 0.67 30 2 Sastrugi 7.0 - 53.5 10.2 9.1 8.8 7.7 7. 3 5.8 6.0 5.2 4.6 4.3 69.0 120 2.9 0.04 31 6 Dune 9.4 - 34.5 14 7.6 98.0 44.1 27.0 18.2 13.5 11.3 10.4 8.8 8.4 387.3 60 36.0 1.38 32 6 · "  9.4 - 34.5 l 77. 5 83.8 39.2 29.0 1 7.1 13.2 10.2 8.8 8.4 7.7 394.9 60 34.9 1.48 37 22 " 78 - 32.0 29.8 21.7 18.1 l 0.5 8.8 6.0 5.9 4.2 3.6 3.4 112.0 120 4.7 0.12 38 22 " 7.8 - 32.0 31.2 20.5 18.9 12.5 9.5 8.0 6.1 5.4 4.3 4.1 120.5 120 5.3 0.13 39 26 Sastrugi 7. 5 - 52.0 15.3 21.3 19.9 20.0 l 7. 8 15.3 14.6 14.4 13.2 13.8 165.6 120 6.8 0.06 40 27 Dune 7.5 - 52.5 134.0 35.4 13.6 7. 7 5.4 3.8 3.1 2.5 2.5 2.0 210.0 60 18.2 1.12 Salta-tion length (cm) 36.5 25.1 21.1 76.0 22.5 22.8 26.6 92.6 28.4 27. 9 115.7 29.5 33.1 128.8 27.3 38.4 15.4 55.0 56.7 57. 2  72.2 9.0 72.5 26.1 23.6 39.2 40.9 113.3 16.3 

IV. DRIFTING SNOW AT SYOWA STATION AND MIZUHO CAMP IN 1971-1972

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IV. DRIFTING SNOW AT SYOWA STATION AND MIZUHO CAMP IN 1971-1972

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