A method is presented by which combined S-band polarimetric weather radar and UHF wind profiler observations of precipitation can be used to extract the properties of liquid phase hydrometeors and the vertical velocity of the air through which they are falling. Doppler spectra, which contain the air motion and/or fall speed of hydrometeors, are estimated using the vertically pointing wind profiler. Complementary to these observations, spectra of rain drop size distribution (DSD) are simulated by several parameters as related to the DSD, which are estimated through the two polarimetric parameters of radar reflectivity (Z H ) and differential reflectivity (Z DR ) from the scanning weather radar. These DSDs are then mapped into equivalent Doppler spectra (fall speeds) using an assumed relationship between the equivolume drop diameter and the drop's terminal velocity. The method is applied to a set of observations collected on 11 March 2007 in central Oklahoma. In areas of stratiform precipitation, where the vertical wind motion is expected to be small, it was found that the fall speeds obtained from the spectra of the rain DSD agree well with those of the Doppler velocity estimated with the profiler. For those cases when the shapes of the Doppler spectra are found to be similar in shape but shifted in velocity, the velocity offset is attributed to vertical air motion. In convective rainfall, the Doppler spectra of the rain DSD and the Doppler velocity can exhibit significant differences owing to vertical air motions together with atmospheric turbulence. Overall, it was found that the height dependencies of Doppler spectra measured by the profiler combined with vertical profiles of Z, Z DR , and the cross correlation (r HV ) as well as the estimated spectra of raindrop physical terminal fall speeds from the polarimetric radar provide unique insight into the microphysics of precipitation. Vertical air motions (updrafts/downdrafts) can be estimated using such combined measurements.

Observations of fogs with a millimeter-wave scanning Doppler radar were conducted at Kushiro in Hokkaido, Japan, in the summer seasons of 1999 and 2000. Three typical types of plan position indicator (PPI) displays were observed: cellular echoes with high radar reflectivity factors (∼−10 dBZ), uniformly distributed echoes with high reflectivities (∼−10 dBZ), and uniformly distributed echoes with low reflectivities (∼−30 dBZ). The authors focused on advection fog with cellular echoes observed on 5 August 1999 and 31 July 2000. Echoes showed structures of cells with a reflectivity of −10 dBZ and with intervals of about 1 km. This echo pattern moved northward (i.e., from the sea to the land). There was a vertical shear of the horizontal wind at a height around 200 m in both cases, and structures of each cell were upright above the shear line and were leaning below it. The direction and the speed of the echo pattern in both PPI and range–height indicator (RHI) displays agreed well with that of the horizontal wind at heights above the shear (200 m). In the echo cells, existence of drizzle drops is implied.

Abstract. Typhoon 9707 (Opal) was observed with the VHF-band Middle and Upper atmosphere (MU) radar, an L-band boundary layer radar (BLR), and a vertical-pointing C-band meteorological radar at the Shigaraki MU Observatory in Shiga prefecture, Japan on 20 June 1997. The typhoon center passed about 80 km southeast from the radar site. Mesoscale precipitating clouds developed due to warmmoist airmass transport from the typhoon, and passed over the MU radar site with easterly or southeasterly winds. We primarily present the wind behavior including the vertical component which a conventional meteorological Doppler radar cannot directly observe, and discuss the relationship between the wind behavior of the typhoon and the precipitating system. To investigate the dynamic structure of the typhoon, the observed wind was divided into radial and tangential wind components under the assumption that the typhoon had an axi-symmetric structure. Altitude range of outflow ascended from 1-3 km to 2-10 km with increasing distance (within 80-260 km range) from the typhoon center, and inflow was observed above and below the outflow. Outflow and inflow were associated with updraft and downdraft, respectively. In the tangential wind, the maximum speed of counterclockwise winds was confirmed at 1-2 km altitudes. Based on the vertical velocity and the reflectivity obtained with the MU radar and the C-band meteorological radar, respectively, precipitating clouds, accompanied by the wind behavior of the typhoon, were classified into stratiform and convective precipitating clouds. In the stratiform precipitating clouds, a vertical shear of radial wind and the maximum speed of counterclockwise wind were observed. There was a strong reflectivity layer called a 'bright band' around the 4.2 km altitude. We confirmed strong updrafts and downdrafts below and above it, respectively, and the existence of a relatively dry layer around the bright band level from radiosonde soundings. In the convective precipitating clouds, Correspondence to: H. Hashiguchi (hasiguti@kurasc.kyoto-u.ac.jp) the regions of strong and weak reflectivities were well associated with those of updraft and downdraft, respectively.

Observations of frontal cirrus clouds were conducted with the scanning millimeter-wave radar at the Shigaraki Middle and Upper Atmosphere (MU) Radar Observatory in Shiga, Japan, during 30 September–13 October 2000. The three-dimensional background winds were also observed with the very high frequency (VHF) band MU radar. Comparing the observational results of the two radars, it was found that the cirrus clouds appeared coincident with the layers of the strong vertical shear of the horizontal winds, and they developed and became thicker under the condition of the strong vertical shear of the horizontal wind and updraft. The result of the radiosonde observation indicated that Kelvin–Helmholtz instability (KHI) occurred at 8–9-km altitudes because of the strong vertical shear of the horizontal wind. The warm and moist air existed above the 8.5-km altitude, and the cold and dry air existed below the 8.5-km altitude. As a result of the airmass mixing of air above and below the 8.5-km altitudes, the cirrus clouds were formed. The updraft, which existed at 8.5–12-km altitude, caused the development of the cirrus clouds with the thickness of >2 km. By using the scanning millimeter-wave radar, the three-dimensional structure of cell echoes formed by KHI for the first time were successfully observed.

A special fog observation campaign was conducted in the Miyoshi basin, Hiroshima prefecture, Japan during the period November 7-15, 2000. We observed the spatial distributions of fogs and their movements using a millimeterwave scanning radar. This is the first time that the distribution of basin fogs associated with fog development and decay processes has been examined. Echo intensity observed with the radar, which is mainly associated with fog particle size, was almost under −23 dBZ at levels below 200 m in height. The horizontal distribution of echo intensity changed with time. Namely, weak echoes were observed over nearly all observation areas at first, and then the echoes gradually became stronger as the fogs developed, although the echoes were weaker at higher levels. After sunrise, the echoes decayed. During the developing periods, the occurrence ratio of the echo intensity between −38 and −23 dBZ increased from the lower height, while the ratio decreased from the higher levels during the decay periods. This feature in the developing period is consistent with the results of optical measurements but the feature in the decaying period is inconsistent. It is suggested that this inconsistency is due to the difference in sensitivity between the two measurement approaches.