Three-dimensional observations of heavy rainfall using a phased-array weather radar

This paper is an overview of a project concerned with “Early warning for torrential rainfall/tornado” under “Enhancement of Societal Resiliency against Natural Disasters,” which is one of eleven themes of the SIP (Cross-ministerial Strategic Innovation Promotion Program under the Council for Science, Technology and Innovation, the Cabinet Office, Government of Japan). The characteristics of the project are the development of a multi-parameter phased array weather radar (MP-PAWR) that enables the accomplishment of an accurate three-dimensional model of precipitation over 30 s within a 60 km radius. Various products developed ducts using MP-PAWR and other observations, and numerical predictions, are also discussed, with a demonstration experiment to provide early warnings for torrential rainfall and related disasters. For end users such as local governments and general citizens, the final goal of this project is the social implementation of these products.

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High-Speed Volumetric Observation of a Wet Microburst Using X-Band Phased Array Weather Radar in Japan

Monthly Weather Review ◽

10.1175/mwr-d-16-0125.1 ◽

2016 ◽

Vol 144 (10) ◽

pp. 3749-3765 ◽

Cited By ~ 10

Author(s):

Toru Adachi ◽

Kenichi Kusunoki ◽

Satoru Yoshida ◽

Ken-ichiro Arai ◽

Tomoo Ushio

Keyword(s):

High Speed ◽

Phased Array ◽

Three Dimensional ◽

Weather Radar ◽

Ground Level ◽

Dimensional Structure ◽

Convection Cell ◽

Low Level ◽

X Band ◽

Traffic Operation

This paper reports a high-speed volumetric observation of a wet microburst event using X-band phased array weather radar (PAWR) in Japan. On 10 September 2014, PAWR observed the three-dimensional structure of a convection cell, which had a vertical extent of 5–6 km and a horizontal dimension of 2–10 km, moving toward the east-northeast. At 2310 Japan standard time (JST), a precipitation core with a radar reflectivity of >40 dBZ appeared at 3–5 km above ground level. The core then increased in size and intensity and rapidly descended to the ground. During this time, a reflectivity notch associated with midlevel inflow was initially formed near the top of the precipitation core and, subsequently, at lower altitudes. A strong low-level outflow with a radial divergence of >4 × 10−3 s−1 appeared just below the notch at around 2321 JST. The outflow lasted for approximately 13 min and eventually disappeared after 2333 JST along with dissipation of the causative storm cell. These results suggest that, in addition to hydrometeor loading, evaporative cooling due to the entrainment of midlevel relatively dry air played an additional role in driving a strong downdraft. The preceding signatures including descending precipitation core, reflectivity notch, and midlevel convergence observed by PAWR are useful precursors to forecast the occurrence of low-level wind shear 5–10 min ahead, which is important for safe air traffic operation.

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Fast high-quality three-dimensional reconstruction from compressive observation of phased array weather radar

2017 Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC) ◽

10.1109/apsipa.2017.8282000 ◽

2017 ◽

Cited By ~ 1

Author(s):

Ryosuke Kawami ◽

Hidetomo Kataoka ◽

Daichi Kitahara ◽

Akira Hirabayashi ◽

Takashi Ijiri ◽

...

Keyword(s):

Phased Array ◽

Three Dimensional ◽

Weather Radar ◽

Three Dimensional Reconstruction ◽

High Quality ◽

Dimensional Reconstruction

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Precipitation Nowcasting with Three-Dimensional Space–Time Extrapolation of Dense and Frequent Phased-Array Weather Radar Observations

Weather and Forecasting ◽

10.1175/waf-d-15-0063.1 ◽

2016 ◽

Vol 31 (1) ◽

pp. 329-340 ◽

Cited By ~ 22

Author(s):

Shigenori Otsuka ◽

Gulanbaier Tuerhong ◽

Ryota Kikuchi ◽

Yoshikazu Kitano ◽

Yusuke Taniguchi ◽

...

Keyword(s):

Phased Array ◽

Dimensional Space ◽

Three Dimensional ◽

Weather Radar ◽

Convective Precipitation ◽

Dimensional Space Time ◽

3D Volume ◽

New Generation ◽

Time Extrapolation ◽

Three Dimensional Space

Abstract The phased-array weather radar (PAWR) is a new-generation weather radar that can make a 100-m-resolution three-dimensional (3D) volume scan every 30 s for 100 vertical levels, producing ~100 times more data than the conventional parabolic-antenna radar with a volume scan typically made every 5 min for 15 scan levels. This study takes advantage of orders of magnitude more rapid and dense observations by PAWR and explores high-precision nowcasting of 3D evolution at 1–10-km scales up to several minutes, which are compared with conventional horizontal two-dimensional (2D) nowcasting typically at O(100) km scales up to 1–6 h. A new 3D precipitation extrapolation system was designed to enhance a conventional algorithm for dense and rapid PAWR volume scans. Experiments show that the 3D extrapolation successfully captured vertical motions of convective precipitation cores and outperformed 2D nowcasting with both simulated and real PAWR data.

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Study on Water Level Prediction Using Observational Data from a Multi-Parameter Phased Array Weather Radar

Journal of Disaster Research ◽

10.20965/jdr.2021.p0410 ◽

2021 ◽

Vol 16 (3) ◽

pp. 410-414

Author(s):

Kazuhiro Yoshimi ◽

Masakazu Wada ◽

Yukio Hiraoka ◽

◽

Keyword(s):

Water Level ◽

Observational Data ◽

Urban Areas ◽

High Speed ◽

Phased Array ◽

Three Dimensional ◽

Weather Radar ◽

Water Levels ◽

Hydrological Processes ◽

Basic Study

A dual-polarization, phased array weather radar, also known as the multi-parameter phased array weather radar (MP-PAWR), was developed by the Japanese Cross-ministerial Strategic Innovation Promotion (SIP) Program. Since this weather radar has been made into an active phased array, three-dimensional observation of weather phenomena can be realized at high speed by means of electrical scanning in the elevation direction and mechanical scanning in the azimuth direction. This is expected to shed light on hydrological processes in river basins, such as those of urban rivers, and improve prediction accuracy. In this study, river water levels in urban areas were estimated from vertically integrated liquid (VIL) Nowcast water content results, a meteorological forecasting method based on the three-dimensional observation MP-PAWR data, using a synthesized rational formula. A runoff analysis for urban basins was carried out using the rainfall forecast results based on MP-PAWR observational data. Since it is known that this formula can be used to deliver a rapid response time for runoff phenomena in the basin, it is possible to fully exploit the features of the MP-PAWR. This study shows how MP-PAWR is used in a series of hydrological processes. In this paper, we report the results of a basic study on water level predictions based on MP-PAWR observational data and also present future prospects for the use of this technology.

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Analysis of a Precipitation System that Exists above Freezing Level Using a Multi-Parameter Phased Array Weather Radar

Atmosphere ◽

10.3390/atmos10120755 ◽

2019 ◽

Vol 10 (12) ◽

pp. 755

Author(s):

Nobuhiro Takahashi

Keyword(s):

Vertical Velocity ◽

Vertical Profile ◽

Phased Array ◽

Three Dimensional ◽

Weather Radar ◽

Cloud Base ◽

Doppler Velocity ◽

Freezing Level ◽

Precipitation System ◽

Fall Speed

An X-band multi-parameter phased array weather radar (MP-PAWR) was developed in 2017. The scan concept of the MP-PAWR is electronic scanning in elevation by combining fan beam transmissions and pencil beam receptions with digital beam-forming techniques and mechanical scanning along the azimuth. The MP-PAWR realized three-dimensional (60 km in radius and 15 km in height) observations without gaps of 30 s. Although the MP-PAWR is supposed to be suitable for observations of rapidly changing convective systems, it can be advantageous for observations of stratiform rainfall because of continuous vertical pointing observations and its ability to apply the Velocity Azimuth Display (VAD) method with a constant radius for a vertical profile of dynamic parameters such as divergence and deformation. In this study, a precipitation system that existed mainly above the freezing level (in this case, it was approximately 5 km in height) observed from 14:00 to 17:00 Japan Standard Time on 6 September 2018 was analyzed using MP-PAWR data. The averaged area of the vertical profile of Z, and the Doppler velocity with fixed elevation showed a stationary structure with time. The average differential reflectivity factor (ZDR) profile with fixed elevation angles showed values that were close to zero and increased with height. Similar characteristics were shown in the average Specific Differential Phase (KDP) profile. Vertical pointing data, especially for Z, ZDR, and Doppler velocity, were utilized when the echo passed over the radar site, and the Doppler velocity showed the acceleration of fall speed below the freezing level. The vertical profile of divergence with a fixed radius was calculated using the VAD method, and the vertical velocity was calculated using the fall speed profile from the vertical pointing data and by assuming the vertical velocity at the cloud base was zero. The results indicate that the updraft region corresponds to higher ZDR and KDP regions.

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