Global structures of stationary planetary waves in the middle atmosphere are studied by using the linearized primitive equations in spherical coordinates and by imposing observed heights as the lower boundary condition under realistic zonal wind configurations at the winter solstice and the vernal equinox of the northern hemisphere. The results for winter season show that the calculated amplitudes of WN=1 (wavenumber 1) in the global primitive model are about one half of the observed ones, whereas those of WN=2 nearly same. In the phase profiles for the two wavenumbers, no remarkable differences are seen between the calculated and observed ones. Further it is noted that maximum geopotential amplitudes of WN=1 and 2 are located about 10* latitude northward of the jet maximum, mainly owing to no artificial rigid boundary at the equator. Such characteristics are in agreement with Simmons (1978), but not mainly owing to a-geostrophy as he mentioned. In the results for equinox season, inter-hemispheric coupling through the waves is shown. In the case of WN=1 where the wave forcings at the lower boundary are given in the both hemispheres, cross-equatorially propagating waves from one hemisphere play a role of the energy source in the other hemisphere, and there the wave phase changes with height eastward. In the case of WN=2 where the wave forcings are given only in the northern hemisphere, the amplitudes in the northern mesosphere decrease with decreasing latitude and attain its minimum at the equator. After cross-equatorial propagation, the amplitudes in mid-latitudes of the southern hemisphere, despite of no wave forcings at the lower boundary, recover its magnitude as large as those in the northern hemisphere. It is found that stationary planetary waves in the tropics propagating from mid-latitudes behave like the equatorial Rossby waves with smaller geopotential amplitude and shorter vertical wave-length compared with those in higher latitudes. Zonal flow acceleration due to the waves is investigated in relation to the semi-annual oscillation. At its westerly phase in equinox, WN=2 could cause an easterly acceleration of zonal flow, by -10cm/sec/day, near 45km height in the tropics; this acceleration is comparable order as the observed one. Therefore it may be said that planetary waves could play an important role in the initiation of the easterly phase of the semi-annual oscillation.
Interdiurnal variations of sea level pressure and surface temperature are studied using the WMONEX/FGGE level II-b data set for the region bounded by 30N-10S and 100E-130E during December 1978. Results of spatial cross correlation patterns indicate an eastward phase propagation of pressure and temperature maxima with speed∼10 longitude per day over the Southeast China and adjacent ocean, apparently associated with the travelling midlatitude disturbances. In the meridional direction, pressure oscillations in the midlatitudes are highly correlated with that over Indochina for three consecutive days but not with those over the bulk of the South China Sea. This difference in correlations indicates a change in the characteristics of the air mass as it traverses land and sea. Temperature analysis also implies the influence of heat transfer between the ocean and atmosphere to the areas south of 15N. An eigenvector analysis is applied to both the pressure and the temperature series. The first eigenmode resembles the pattern associated with the East Asia local Hadley circulation. The second eigenvector represents wintertime anticyclone and cyclone patterns over Southeast China and its adjoining ocean, and thus the cold surge events. Time series of the first two eigenmodes are discussed in terms of the winter monsoon circulation during this period.
Nature of individual hygroscopic particles, including those in the Aitken size range, was examined by the dialysis of water-soluble material applied to samples collected on a carbon covered nitrocellulose film supported on an electron-microscopic grid. The samples were collected by a low-pressure impactor in the urban atmosphere of Nagoya and Yokkaichi. Change in morphology of particles on the collecting surface before and after the dialysis was observed by an electron microscope. More than 80% of aerosol particles of 0.03 to 0.35μm radius were hygroscopic particles. Mixed particles occupied 34% of hygroscopic particles in the Aitken size range (0.03-0.10μm radius) and 67% in the large size range (0.10-0.35μm radius). The volume fraction of water-soluble material ε in individual particles was estimated by the electron microscopic examination. Those with high values of ε(>0.95) were dominant hygroscopic particles of 0.03 to 0.35μm radius.
Collections of aerosol particles were carried out with an electrostatic aerosol sampler in the summertime at Nagoya and Yokkaichi which are heavily polluted areas in Japan. By electron microscopic examination 21 number size distributions of all particles and those of sulfate particles, including those in the Aitken size range, were obtained. Method for the detection of sulfate ions by electron microscopy, proposed by Bigg et al. (1974), was applied to the individual particles. Sulfate particles were found to be predominant in the range of 0.016 to 0.28λm radius and they were detected with high number fractions of particles, 55 to 75% on the average. It is considered that the distributions of aerosol particles in the Aitken size range were closely related to the behavior of sulfate particles formed by gas-to-particle conversion influenced by the amount of pre-existing particles.
A simple method for taking the side view and the stereo-photomicrographs of plate-like snow crystals was described and examined their three-dimensional structures and the thickness from the photographs. The results show that most of plate-like snow crystals consist of two or more plate-like crystals which have different forms and sizes and their thickness was thinner than that observed by Ono (1969) and Auer and Veal (1970). The falling attitude of double plates was infered to be fallen with smaller plate oriented downward from the observation of their riming properties and the snow crystals which were replicated in natural falling conditions. Further, the growth conditions of natural dendritic snow crystals were briefly discussed.
A high sensitive chemiluminescent detector of NOx (NO and NO2) has been developed for the aircraft measurements in the clean troposphere. The characteristics of the first version of the instrument is presented. The measurement of NO is based on the chemiluminescent reaction with ozone supplied in the instrument. For NO2 measurements, a ferrous sulfate converter is used to convert NO2 to NO before introducing into the reaction chamber. The pressure in the reaction chamber is controlled to be a constant value to keep the sensitivity stable in the ambient variable atmospheric pressure. The sensitivity response of the detector in the region below 10ppb is linear within 5% and has been found to be 250-300counts/s/ppb in the altitude range from the ground to 7km. The sensitivity of the detector is repeatedly checked during flights. The detection limit of NOx determined by the sensitivity and the fluctuation of the background signal is 10-15ppt.