The Japan Meteorological Agency (JMA) started the operation of a wind profiler network, the WInd profiler Network and Data Acquisition System (WINDAS), in April 2001. The WINDAS is a network consisting of thirty-one 1.3 GHz-band wind profilers, with dense spatial resolution of 130 km on the average over the main islands of Japan. Operated with high data accuracy, under strict data quality control and high data availability, from reliable system operation. Height coverages of wind measurement are 6-7 km in summer, 3-4 km in winter and 5.3 km on the average through a year. The main purpose of the operation of WINDAS is to provide upper-air wind data to the numerical weather prediction (NWP) of the JMA, particularly to the hydrostatic (till 2004) and non-hydrostatic (from 2004) mesocale numerical model (MSM). The WINDAS data are assimilated into the MSM using a full forecast-analysis system, with 4-dimensional variational method. From statistical analyses and some case studies, it was conformed that the WINDAS data has contributed to improve accuracy of the MSM for mesoscale weather systems, particularly for heavy rainfall events. Being put on GTS, the wind data are distributed to the world in real-time. Although a problem of data contamination from migrating birds had occurred in the first year of the operation of the WINDAS, it was practically solved by developing a removal algorithm.

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Two ground-based Doppler radars have been used to examine the wind fields and the internal structure of the rainband of Typhoon 8305. The rainband is located 300km to the northeast of the storm center and is embedded in a broad stratiform precipitation region.The air flow around the rainband is nearly two-dimensional along the rainband. Composite crosssections in the radial direction from the storm center reveal the secondary circulation associated with the rainband. A convergence zone with a large outward tilt exists from the inner edge of the rainband (the edge near the storm center) at lower levels to the outer edge at middle levels. Frictional inflow air at lower levels rises at the inner edge of the rainband and a mesoscale updraft of 2m s-1 forms. A mesoscale downdraft less than 1m s-1 exists in the maximum reflectivity zone outside the updraft zone. The downdraft is thought to be produced by the drag forces and evaporation of raindrops. The convergence between the relatively cold air associated with the downdraft and the low-level warm inflow relative to the storm center produces the updraft. This cloud dynamic mechanism is thought to play the main role in maintaining the rainband.

The structure of the rainbands and eyewall of Typhoon 8514, which landed at the central region of Japan on 30 August 1985 was observed by two ground-based Doppler radars. The main purpose of the present study is to describe a general view of the structure of the typhoon using data of the dual-Doppler radar.Although the typhoon was a small and weak typhoon, it retained the characteristics of tropical cyclones: it was accompanied by spiral rainbands (an outer rainband and an inner rainband) and had a warm core in its upper part.The outer rainband was a spiral band located about 150 km from the center of the typhoon. This rainband consisted of continuous stratiform clouds and scattered convective clouds. A radar "bright band" was observed in this rainband. Wind perturbation induced by cooling-by-melting was observed just below the bright band. An updraft of 1.5 ms-1 was produced, mainly owing to the convergence of a southeasterly flow on the inner edge of the outer rainband. This updraft maintained the outer rainband.The inner rainband was a convective spiral band located *60 km from the typhoon center. The distribution of reflectivity and vertical velocity of this rainband indicated that an old echo cell existed in the inner part, while young echo cells existed in the outer part of this rainband. An inflow (the airflow toward the typhoon center) was observed in the lower layers of the inner rainband. This inflow reached the inner edge of the young cells, and produced an updraft there. When the depth of this inflow layer became thinner, the inner rainband decayed. This indicates that the inflow had an important role to play in maintaining the inner rainband.Because the flow into the eyewall of the typhoon in the lower layers was weak, the radius of maximum wind (RMW) was located at the outer side of the axis of reflectivity maxima. The eyewall decayed when it moved to the inner area (nearer the typhoon center) of the RMW, where downdraft was predominant.