This paper describes an analysis of the structure of a tropical squall line by the use of radar, satellite, and upper air sounding data. The observation was made in the west of the western tropical Pacific during Summer MONEX in 1979. The results of the analysis were compared with the structure of tropical squall lines observed by other authors.
   The squall line in this study showed a significantly organized mesoscale structure; that is, cumulus-scale convections and organized convections were combined within it. The existence of organized convection was the particular feature of this squall line. Anvil clouds covered these convections and extended back from the leading edge for more than 200 km. The line-shaped leading edge of the squall line propagated at a speed larger than that of ambient winds. Some portions of the leading edge were not dissipated and grew into organized convections, which maintained size and intensity for several hours.
   The squall line was formed in the boundary region between the monsoon southwesterly and the trade wind easterly in the lower troposphere. Just before the squall line was formed, a relatively large positive vorticity had existed in the middle and lower troposphere, and a large divergence of air above 400 mb and moderate convergence below 400 mb. The overturning of the atmosphere was found by upper sounding data, and the moist static energy located in the lower troposphere ahead of the squall line was thought to be an energy source of the formation of the squall line.
   Several common properties were seen in tropical squall lines in our case and in other tropical regions, but the cloud structure of the squall line in our case should be discussed three-dimensionally because of the existence of the organized convections.

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   A method of spectrum analysis using electrical filters, that is, the band-pass sigma meter and the high-pass sigma meter, and their characteristics are investigated.
   It is found, from the results processed by the band-pass sigma meter, that the spectrum shows the one which is averaged for a fairly long time and smoothed. It is also found that this method is very useful and effective in deciding the peak frequency of the spectrum though the spectrum functions can not be obtained so accurately when the spectrum is not distributed in a relatively wide frequency range.
   This method of estimating an energy spectrum is applicable not only to laboratory data but also to field ones.
   It is shown by graphical calculation of the spectrum that the method of spectrum analysis using several high-pass sigma meters of which the transfer functions are the 4th order or more higher order is more proper than that using the band-pass sigma meter, in obtaining a spectrum accurately.

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   Meso-meteorological analysis on the Hokuriku foehn was carried out using AMeDAS data. Selecting the central Japan area as the analysis area, time series of the spatial distribution of wind, temperature and humidity fields are obtained.
   The surface winds blowing from the Pacific Ocean side to the Hokuriku district, take their course along the valleys which run from south to north in the central mountain ranges. There are three wind courses in the ranges, and strong foehn wind areas in the coastal plains along the Japan Sea side sector of these courses. Foehn wind varies diurnally, light by day and strong at night, which suggests the superposed effect of the southerly synoptic wind and the diurnally varying local wind. During foehn, there is sometimes a rainfall and sometimes none on the windward side. It is found that the Scorer parameter as well as moisture condition in the lower troposphere is responsible for the appearance of the windward rainfall.

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   A new method of fluorometric determination of total and organic aluminum dissolved in sea water is described. Separation of total aluminum from sea water is done by adsorption of Al-oxine complex on XAD-2 resin, and that of organic aluminum compounds is carried out by XAD-2 adsorption method using two different pH conditions of the solution; pH of natural sea water and pH 3. The determination of Al is done by measuring the fluorescence intensity of Al-oxine complex in CHCl₃ media. The recovery of this method is 97.5%, and the detection limit is 0.08 μg of Al. The standard deviation of this method is less than 3%. Results of determination of Al in the western North Pacific, Indian and Southern Oceans indicate that Al dissolved in sea water, the content of which is ranges from 0.8 to 1.2 μg 1^-1 (average 0.8 μg 1^-1), is found to be mostly inorganic forms. The results of study in coastal water off Tokai-mura, Japan, is also given in briefly.

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   Distance measurements to estimate ground deformation by use of the AGA Geodimeter-6BL were carried out at intervals of 3 to 4 months at four active volcanoes in Japan: Asamayama, Izu-Oshima, Asosan and Sakurajima. These volcanoes have had frequent eruptions and volcanic earthquakes in historical time. Base lines for measurement are set on 6 lines at Asamayama, 7 at Izu-Oshima, 8 at Asosan and 9 at Sakurajima. Total numbers of surveys for all base lines are counted 184 times during the two years 1975-1976 and 1977-1978.
   The accuracy of distance measurement depends on the sum of the observation error (E) and the normal error (e). (E) is the standard deviation of the observation data and (e) is the error due to the setting condition and secular variation of the instrument, weather condition at the observation time, etc.
   The total maximum error (S_max) and the total mean error (S_mean) are statistically expressed as follows:
where D is the length of the base line in km.
   The total error for each base line was of the order of 10^-6 strain. On the other hand, the observed strain was of the order of 10^-5 strain at all base lines during the two years. On the other hand, 10^-6∼10^-7 strain was reported in nonvolcanic regions in the same period. It is worth noticing that the strain of the volcanic region is larger than that of other regions.
   In this paper, the base line with a variation of strain larger than twice the total error is conveniently named “the significant line”. Such lines are detected at the SSE and the NE foot of Asamayama, at the central cone “Miharayama” and foot of Izu-Oshima, near the Nakadake crater of Asosan, and at the NW to W and S foot of Sakurajima. The significant lines at the W foot of Sakurajima are located in a direction crossing the tectonic line of the “1914 Taisho Eruption”.
   Variation of strain of the significant lines has a good correlation with volcanic eruption and or seismic activity in and near the volcano. Expansion of the base line was often observed during an active period of the volcano, while contraction was found during a calm stage. These phenomena suggest that the pressure of the magma reservoir and the vent increases during an active period, so that the diameter of the crater and the width of the tectonic line of the volcano spread outward. On the other hand, the pressure decreases during a calm stage, so that the crater and the tectonic line contract inward.
   For the study of the relationship between volcanic activity and ground deformation at the above-mentioned four active volcanoes, it is useful to make the distance survey by the Geodimeter, at intervals of three months or less.

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