Cloud Snow Research Articles

Effect of Root Temperature and Photoperiod on Growth and Crop Productivity Efficiency of Petunia1

Abstract Seedlings of Petunia hybrida cv. Snow Cloud were subjected to root zone temperatures at the bottom surface of the pots of 15.6° to 19.4°C (NT) or 21° to 35° (HT) and photoperiods of 9 (SD) or 13 hr (LD) for 25 days in a eontrolled-environment chamber with air temperatures of 21° for 9 hr and 15.6° for 15 hr. HT × LD plants produced the largest total leaf area, largest main stem leaves, and most dry weight of all treatments; they were tallest and bloomed first, but had the fewest lateral branches. HT × SD plants developed the most lateral branches at the fastest rate and had a total leaf area, dry weight gain, and root development comparable to those of the LD treatments. NT × SD plants were the smallest. Crop productivity efficiency was determined to be NT × SD = 2.9%, HT × SD = 3.4%, NT × LD = 3.7%, and HT × LD = 3.9%.

Remote Sensing for Nuclear Power Plant Siting

It is shown that satellite remote sensing provides timely and cost-effective information for siting and site evaluation of nuclear power plants. Side-looking airborne radar (SLAR) imagery is especially valuable in regions of prolonged cloud cover and haze, and provides additional assurance in siting and licensing. In addition, a wide range of enhancement techniques should be employed and different types of image should be color-combined to provide structural and lithologic information. Coastal water circulation can also be studied through repetitive coverage and the inherently synoptic nature of imaging satellites. Among the issues discussed are snow cover, sun angle, and cloud cover, and actual site evaluation studies in the Bataan peninsula of the Philippines and Laguna Verde, California.

Some Observations of Snowfall and Meteorological Conditions in Arctic Canada

Abstract Observations of snow crystals were made in mid-winter at Inuvik, N.W.T., Canada, in order to study the snow crystal of cold temperature type. The following results were obtained: 1) The cloud temperature was, in general, warmer than expected during the observation period, that is, nearly the same as observed in snow clouds in midlatitudes, although the surface temperature was lowered to −30 or −40°C. 2) Regarding the type of snow crystals, Nakaya's Ta-s diagram was well applicable to the snow crystal in Arctic Canada. 3) Almost every day during the observation period, snowfalls were observed; however the fall intensity was as light as 1 or 2 cm day−1. In the case of a moderate snowfall of 5.1 cm day−1, the snowfall was caused by an arctic front at the 850 mb level. The vapor for the snowfall was supplied from the warm surface of the eastern or northern Pacific Ocean. 4) One day, small supercooled raindrops were observed, but no cloud region of temperature warmer than 0°C was detected in the cloud...

降水を伴う雪雲の大気電気的性質

Simultaneous observations of the surface electric field, shape and charge on snow crystals and melted diameters of the crystals were carried out at the seashore of Ishikari near Sapporo where snow clouds of falling snow accompanied by northwesterly winds were observed during the winter monsoon season.From the observational results, it was confirmed that in general dendritic crystals were negatively charged under a positive electric field and relatively large dendritic snowflakes, densely rimed crystals and soft hail were positively charged under a negative electric field. Furthermore, it was found that when positive snow crystals fell, the mode value of the size distribution of melted diameter at that moment shifted to smaller values as compared with that when negative snow crystals fell alone. Therefore, it was considered that snowflakes and densely rimed crystals were positively charged when small fragments were torn off from fragile flakes and crystals during their descent and at such times small fragments acquired negative charges. Moreover, suspended small fragments acquired negative charges when they collided with the falling flakes and crystals. As a result, the main crystals acquired positive charges as a matter of course.

雪結晶ゾンデにより観測された雪雲の垂直構造,其の1

Experimentally the collection efficiency of snow crystals by snow crystal sondes was determined to be 36%. This value was smaller than that calculated from Langmuir and Blodgetts' chart, assuming a ribbon shape for the collecting body. However, since the value determined experimentally was considered to be more practical, it was adopted in the measurement of snow crystals in clouds.Sometimes cloud droplets were collected by the snow crystal sonde in snow clouds, and they showed a reasonable size distribution insofar as cloud droplets with diameters greater than 20μ were concerned.

レーダー写真の実体鏡手法による,雪雲の微細構造の解析

レーダー写真の実体鏡手法による,雪雲の微細構造の解析

雪結晶ゾンデにより観測された雪雲の垂直構造,其の2

雪結晶ゾンデにより観測された雪雲の垂直構造,其の2

冬霧の中での地上電位傾度の観測

In winter fogs, when the polluted air or liquid fog came over, the potential gradient increased positively to several times of normal value. This increase in the potential gradient was explained by the decrease of the air conductivity.Accompanying with the glaciation of those liquid fogs, the positively enhanced potential gradient decreased to the normal values or even negative values.About the decrease due to the glaciation following mechanisms are considered. Ice crystals carried preferentially the negative charge. The conductivity of the air increased by the removing submicron aerosols due to the growth of ice crystals (Facy effect).At times, it was observed that when the snowfall stopped, the potential gradient abruptly increased to positive high values. About the mechanism, it was considered that the residual positive space charge was gravitationally separated from the negative snow crystals, then the positive space charge was brought down to the surface by downdraft between snow clouds.

冬霧と降雪における電位傾度の鉛直分布,尖端放電々流及びアンテナ•アース電流の観測

Various electrical properties of winter fog were measured at Asahikawa in 1968, following the previous observation as reported in Part I (Endoh, Iwabuchi and Magono 1972).From the results of measurement of the vertical distribution of the potential gradient in a fog layer, it was found that the electric potential gradient in a fog layer was greater than that above the layer. This was considered to be caused by the smaller conductivity of the air in the fog layer.When a snow cloud passed overhead during the fog, a high negative point discharge current was observed. This was explained by the negative potential gradient at the point due to the negative space charge of the snow cloud.Peculiar changes were noticed in the antenna-earth current, and they were explained by the effect of the smoke from steam locomotives, flapping of crows' wings, falling off of frost pieces from the antenna line, and the sheathing-layer-like phenomenon on the upper surface of the fog layer.

Study on Heavy Snowfalls in Kyushu

Recently, also in the warm region Kyushu, which is situated in the south-western area of Japan Islands, a local snowfall has become one of the important meteorological phenomena in winter, since snowfalls have many influences upon agriculture, trasportation, especially in the high-way road which nowadays is going to develop, water resources and so on. The authors have investigated snowfalls by means of the climatological analysis and general synoptic analysis, and had a chance to observe the natural snow crystals and snowflakes associated with the snow clouds developed in the north-west monsoon period, Feb. 5th to 7th in 1969. The snow crystals and flakes were observed with the method of the macroscopic sketch, the replica observation, the close lens camera, and the photographic recording. By those analyses described above it is found that when we have much snow in Kyushu where usually the snowfall occurrence is very rare and its amount is very little, the synoptic conditions and the pattern of snowfall distribution are quite similar to those when the heavy local snowfalls occurred in the coastal regions of Japan Sea. Results of analyses are summarized as follows.1) In large scale synoptic situation, when the cold and dry air mass from the Siberian Continent comes down southward near the northern part of Korean Peninsula and then passes over the Japan Sea, it is modified with heat and vapor from the sea water below and becomes an unstable air mass.2) The occurrence of snowfall is characterized by the strong wind zone near the 850mb level. This corresponds to the strong curvature of wind profile explained previously by Higuchi.3) In meso scale synoptic situation, local lines of convergence appear along the north and south-west coast of Kyushu. Those are made due to the cooling effect of radiation in the inland area and increases in the rate of precipitation.4) Types of Radar Echoes observed support that the snow clouds are convective ones and show their band structure which is characteristic to local heavy snowfalls in Hokuriku and Hokkaido.5) Snowfall distribution shows that much amount of preciptation is seen rather in the lower plain, and this is quite similar to local heavy snowfalls in the coastal region of the Japan Sea.6) Snow crystals observed at Mt. Hiko are almost consistent with the expected ones by Nakaya's Ta-S diagram.

Photogrammetry Applied to Avalanche Studies

Stereophotogrammetric techniques were used for a study of snow avalanches. The contour lines of the avalanche slope were mapped from stereo-photographs taken before and after the occurrence of the avalanche. The outline of the avalanche front at certain time intervals and the contours of the snow cloud were also plotted. A relative accuracy for the different maps of 0.7 m. on the terrain was established.The volume of the snow cloud at four different stages of the avalanche was determined from the maps. These volumes were also computed independently from coordinate readings that were made in the stereo models. The standard errors of both methods of volume determination were estimated to be 450 m.3 and 290 m.3 respectively, representing errors of 5 per cent and 3 per cent of the average cloud volume.The photographs were taken with an accurately determined time interval. Therefore, the velocity of the avalanche front could be determined from the photogrammetric measurements.

Photogrammetry Applied to Avalanche Studies

Stereophotogrammetric techniques were used for a study of snow avalanches. The contour lines of the avalanche slope were mapped from stereo-photographs taken before and after the occurrence of the avalanche. The outline of the avalanche front at certain time intervals and the contours of the snow cloud were also plotted. A relative accuracy for the different maps of 0.7 m. on the terrain was established. The volume of the snow cloud at four different stages of the avalanche was determined from the maps. These volumes were also computed independently from coordinate readings that were made in the stereo models. The standard errors of both methods of volume determination were estimated to be 450 m.3 and 290 m.3 respectively, representing errors of 5 per cent and 3 per cent of the average cloud volume. The photographs were taken with an accurately determined time interval. Therefore, the velocity of the avalanche front could be determined from the photogrammetric measurements.

Design of “Snow Crystal Sondes”

A sampling and recording sonde, called a “Snow Crystal Sonde,” was designed to observe the vertical distribution of snow crystals in a snow cloud. The shape of snow crystals was recorded on the surface of a circulating film coated with polyvinyl formvar solution during the ascent of the sonde. A radiosonde was released at the same time and place as the snow crystal sonde, in order to render a precise comparison between the snow crystal shape and the air temperature in the cloud. As the result of observation it was ascertained that Nakaya's Ta−s diagram was completely applicable to the growth of natural snow crystals. The snow crystal sonde was also found to be useful to measure the growth rate of snow crystals, and the space density of snow crystals and supercooled cloud droplets.

CLOUD STREETS

The formation and development conditions of the cloud streets over the yellow sea by the Cold Surge of Siberian Anticyclone Expansion which produce the heavy snowfall events over the southwestern coast, Honam District of the Korean peninsula, has been investigated through analyses of the three dimensional snow cloud structures by using the CAPPI, RHI, VAD and VVP data of X-band Radar at Muan Weather Observatory and S-band Radar at Jindo Weather Station. The data to be used are obtained from January 04, 2003, when heavy snow storm hits on Gwangju and Honam District. The PPI Radar images show that the cloud bands distribute in perpendicular to the expansion direction of the high pressure and that the radius of cloud cells is about 5~8 km with 20~30 dBz and distance between each cell is about 10 km. And but the vertical Radar images show that the cloud street is a small scale convective type cloud within height of about 3 km where a stable layer exists. From the VVP images, the time period of the high pressure expansion, the moving direction and development stages of the system are delineated. Finally, the vertical distribution of wind direction is fairly constants, while the wind speed sheer increases with altitude to 3 km.

雪雲の観察

Photographic observations from aircraft were carried out on the snow clouds in December 1960. The results of observations will be described separately under the following three headings : that is, layer clouds, shower clouds and snow trails. It was concluded from analysis of the photograph of the layer clouds (Photo. 1) that the distance between two precipitating cells was reasonable in comparison with the calculated value of the wave length of the internal waves, as described in section 3 a). The formation of the ragged cloudlets near the shower clouds (Photos. 6 and 7) can be explained as due to lifting of the air by the downdraf t spreading out of the shower clouds. The observed shapes of the snowtrails in Photo. 5 was in agreement with that estimated from the wind profile as seen in Fig. 8.