A dust storm which originated in the China desert area covered the Japan Islands on April 14-15, 1979. Simultaneous measurement by lidar and geosynchronous meteorological satellite enabled the spacial structure and transport path of the dust storm cloud to be characterized. The horizontal scale of the dust cloud was about 1.36 x 106 kmz, and the total dust particle mass load was at least -1.63 x lo6 tor1/1.36 x lo6 km2. The lidar measurements indicated that the dust cloud consisted of 2 distinct layers, one at 6 km height and the other at 2 km. The trajectory analysis of air mass suggests that the particulate matter contained in the upper layer is probably transported from the Takla-Makan desert and that in the lower layer from the Gobi desert and the Huang-Ho basin.

A dust storm which originated in the China desert area covered the Japan Islands on April 14–15, 1979. Simultaneous measurement by lidar and geosynchronous meteorological satellite enabled the spacial structure and transport path of the dust storm cloud to be characterized. The horizontal scale of the dust cloud was about 1.36 × 106 km2, and the total dust particle mass load was at least ∼1.63 × 106 ton/1.36 × 106 km2. The lidar measurements indicated that the dust cloud consisted of 2 distinct layers, one at 6 km height and the other at 2 km. The trajectory analysis of air mass suggests that the particulate matter contained in the upper layer is probably transported from the Takla‐Makan desert and that in the lower layer from the Gobi desert and the Huang‐Ho basin.

The modification process of convective snow-clouds in landing the Japan Sea coastal region was observed quantitatively by a RHI radar which was set at Wajima in the Noto Peninsula. The analysis of observational data-was made mainly for snow-clouds in two cases of A and D-in case A the outbreak of cold air became intensive with time after the passage of a low pressure and in case D it was predominant persistently.In both cases most of convective radar-echoes which travelled from the sea showed two stages of variation of echo structure in their landing. In the first stage the echo becomes intensive in its center before landing. Its most intensive part descends several kilometers offshore and the other part found out in its frontal side extends upward with time. The latter part descends inland rapidly after having crossed over the seashore. In the second stage seen after landing the intensity of the echo increases gradually again as a diffused broad echo. In the first stage graupels were observed on the ground predominantly and in the second stage snowflakes were observed as predominant particles. It was suggested from the comparison of echo intensity over the sea with that over the land that the amount of snowfall seen in the seaside of the peninsula was larger than that in the land side in case D, while it was smaller than that in the land side in case A.

Doppler radar observations were carried out to investigate thundercloud generation in the northern Kanto area from July to September 1997. At the end of August 1997 when the upper thermal trough was passing over central Japan, the initial thunderclouds (first echoes) were generated mainly in the evening, at the foot of mountains below 1000 m. Many of the first echoes were generated at an altitude of 4-5 km (A.G.L.). In regard to the relationship between the altitude of first echo generation and Cloud to Ground (CG) flashes, the first echoes, which were generated at 6 km A.G.L. (at the altitude of-10 °C), brought CG flashes at the highest rate. The case study of 29 August 1997 showed that many thunderclouds developed quickly over Mt. Akagi, north of Maebashi city in the northern Kanto area, and the CG flashes occurred actively both under the strong echo region (32 dBZ and over) and weak echo region (under 32 dBZ) in the life cycle of the echo cells.

The size distribution function of aerosols in the lower atmosphere (*0km *2km) measured by the two-wavelength lidar technique is compared with the results determined by an airborne optical particle counter. The comparison shows following facts,1) The vertical changes of size distribution functions determined by the lidar technique show good agreements with the results of the airborne particle counter in a qualitative sense.2) The parameter of * in the size distribution function for aerosol radius R, n(R)= AR-* can be fully accurately determined by the lidar measurements, but the estimation of the other parameter A contains some uncertainty.The remote sensing technique for the size distribution, function should contribute to the study of aerosol growth process, aerosol transformation process, aerosol transport process due to air motion in lower atmosphere, and so on.