Accuracy of Radar-AMeDAS Precipitation

Ysutaka MAKIHARA; Naotaka UEKIYO; Akira TABATA; Yoshiyuki ABE

Accuracy of Radar-AMeDAS Precipitation

Ysutaka MAKIHARA, Naotaka UEKIYO, Akira TABATA, Yoshiyuki ABE

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A verification is made on the accuracy of Radar-AMeDAS precipitation, which represents hourly precipitation over the Japanese Islands and the surrounding sea area with a spatial resolution of 5km using data from 5cm conventional radars, 10cm Fujisan Radar, and Automated Meteorological Data Acquisition System (AMeDAS) raingauge network. By comparing with data from a very dense raingauge network of the Tokyo Metropolitan Government, it is found that 1) Radar-AMeDAS precipitation shows good agreement if a positioning error of one pixel of 5km square is allowed 2) Radar-AMeDAS precipitation represents almost the average of raingauge measurements in the 5km square for most of the precipitation caused by a large scale disturbance, and 3) Radar-AMeDAS precipitation is close to the maximum raingauge measurement in the pixel when precipitation is extremely localized such as thunderstorms or showers. Radar-AMeDAS precipitations are compared also with AMeDAS measurements statistically with respect to the appearance rates, that is (total number of pixels where specific intensity is observed) / (total number of all pixels), for different precipitation intensities. The rate of Radar- AMeDAS precipitation shows excellent agreement with that of AMeDAS if radar echoes are observed at the altitude lower than 2km. Since Radar- AMeDAS precipitation on land sometimes represents the maximum of precipitation in a pixel for the purpose of unfailingly detecting extremely localized severe precipitation, it shows a high appearance rate at high precipitation intensity than AMeDAS, which is considered to represent statistically the average of a pixel. As a result, in estimating areal rainfall amounts, Radar- AMeDAS precipitation overestimates AMeDAS measurement by 8% at 5mm/h and by 12% at 40mm/h. Radar- AMeDAS precipitation over the sea, with no local calibration by AMeDAS and with little influence of orography, is 2% weaker in intensity than AMeDAS at 10mm/h, and 12% at 40mm/h.

Publication: IEICE TRANSACTIONS on Communications Vol.E79-B No.6 pp.751-762

Publication Date: 1996/06/25

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Type of Manuscript: Special Section PAPER (Special Issue on Weather Radar Technology)

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Ysutaka MAKIHARA, Naotaka UEKIYO, Akira TABATA, Yoshiyuki ABE, "Accuracy of Radar-AMeDAS Precipitation" in IEICE TRANSACTIONS on Communications, vol. E79-B, no. 6, pp. 751-762, June 1996, doi: .
Abstract: A verification is made on the accuracy of Radar-AMeDAS precipitation, which represents hourly precipitation over the Japanese Islands and the surrounding sea area with a spatial resolution of 5km using data from 5cm conventional radars, 10cm Fujisan Radar, and Automated Meteorological Data Acquisition System (AMeDAS) raingauge network. By comparing with data from a very dense raingauge network of the Tokyo Metropolitan Government, it is found that 1) Radar-AMeDAS precipitation shows good agreement if a positioning error of one pixel of 5km square is allowed 2) Radar-AMeDAS precipitation represents almost the average of raingauge measurements in the 5km square for most of the precipitation caused by a large scale disturbance, and 3) Radar-AMeDAS precipitation is close to the maximum raingauge measurement in the pixel when precipitation is extremely localized such as thunderstorms or showers. Radar-AMeDAS precipitations are compared also with AMeDAS measurements statistically with respect to the appearance rates, that is (total number of pixels where specific intensity is observed) / (total number of all pixels), for different precipitation intensities. The rate of Radar- AMeDAS precipitation shows excellent agreement with that of AMeDAS if radar echoes are observed at the altitude lower than 2km. Since Radar- AMeDAS precipitation on land sometimes represents the maximum of precipitation in a pixel for the purpose of unfailingly detecting extremely localized severe precipitation, it shows a high appearance rate at high precipitation intensity than AMeDAS, which is considered to represent statistically the average of a pixel. As a result, in estimating areal rainfall amounts, Radar- AMeDAS precipitation overestimates AMeDAS measurement by 8% at 5mm/h and by 12% at 40mm/h. Radar- AMeDAS precipitation over the sea, with no local calibration by AMeDAS and with little influence of orography, is 2% weaker in intensity than AMeDAS at 10mm/h, and 12% at 40mm/h.
URL: https://global.ieice.org/en_transactions/communications/10.1587/e79-b_6_751/_p

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@ARTICLE{e79-b_6_751,
author={Ysutaka MAKIHARA, Naotaka UEKIYO, Akira TABATA, Yoshiyuki ABE, },
journal={IEICE TRANSACTIONS on Communications},
title={Accuracy of Radar-AMeDAS Precipitation},
year={1996},
volume={E79-B},
number={6},
pages={751-762},
abstract={A verification is made on the accuracy of Radar-AMeDAS precipitation, which represents hourly precipitation over the Japanese Islands and the surrounding sea area with a spatial resolution of 5km using data from 5cm conventional radars, 10cm Fujisan Radar, and Automated Meteorological Data Acquisition System (AMeDAS) raingauge network. By comparing with data from a very dense raingauge network of the Tokyo Metropolitan Government, it is found that 1) Radar-AMeDAS precipitation shows good agreement if a positioning error of one pixel of 5km square is allowed 2) Radar-AMeDAS precipitation represents almost the average of raingauge measurements in the 5km square for most of the precipitation caused by a large scale disturbance, and 3) Radar-AMeDAS precipitation is close to the maximum raingauge measurement in the pixel when precipitation is extremely localized such as thunderstorms or showers. Radar-AMeDAS precipitations are compared also with AMeDAS measurements statistically with respect to the appearance rates, that is (total number of pixels where specific intensity is observed) / (total number of all pixels), for different precipitation intensities. The rate of Radar- AMeDAS precipitation shows excellent agreement with that of AMeDAS if radar echoes are observed at the altitude lower than 2km. Since Radar- AMeDAS precipitation on land sometimes represents the maximum of precipitation in a pixel for the purpose of unfailingly detecting extremely localized severe precipitation, it shows a high appearance rate at high precipitation intensity than AMeDAS, which is considered to represent statistically the average of a pixel. As a result, in estimating areal rainfall amounts, Radar- AMeDAS precipitation overestimates AMeDAS measurement by 8% at 5mm/h and by 12% at 40mm/h. Radar- AMeDAS precipitation over the sea, with no local calibration by AMeDAS and with little influence of orography, is 2% weaker in intensity than AMeDAS at 10mm/h, and 12% at 40mm/h.},
keywords={},
doi={},
ISSN={},
month={June},}

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TY - JOUR
TI - Accuracy of Radar-AMeDAS Precipitation
T2 - IEICE TRANSACTIONS on Communications
SP - 751
EP - 762
AU - Ysutaka MAKIHARA
AU - Naotaka UEKIYO
AU - Akira TABATA
AU - Yoshiyuki ABE
PY - 1996
DO -
JO - IEICE TRANSACTIONS on Communications
SN -
VL - E79-B
IS - 6
JA - IEICE TRANSACTIONS on Communications
Y1 - June 1996
AB - A verification is made on the accuracy of Radar-AMeDAS precipitation, which represents hourly precipitation over the Japanese Islands and the surrounding sea area with a spatial resolution of 5km using data from 5cm conventional radars, 10cm Fujisan Radar, and Automated Meteorological Data Acquisition System (AMeDAS) raingauge network. By comparing with data from a very dense raingauge network of the Tokyo Metropolitan Government, it is found that 1) Radar-AMeDAS precipitation shows good agreement if a positioning error of one pixel of 5km square is allowed 2) Radar-AMeDAS precipitation represents almost the average of raingauge measurements in the 5km square for most of the precipitation caused by a large scale disturbance, and 3) Radar-AMeDAS precipitation is close to the maximum raingauge measurement in the pixel when precipitation is extremely localized such as thunderstorms or showers. Radar-AMeDAS precipitations are compared also with AMeDAS measurements statistically with respect to the appearance rates, that is (total number of pixels where specific intensity is observed) / (total number of all pixels), for different precipitation intensities. The rate of Radar- AMeDAS precipitation shows excellent agreement with that of AMeDAS if radar echoes are observed at the altitude lower than 2km. Since Radar- AMeDAS precipitation on land sometimes represents the maximum of precipitation in a pixel for the purpose of unfailingly detecting extremely localized severe precipitation, it shows a high appearance rate at high precipitation intensity than AMeDAS, which is considered to represent statistically the average of a pixel. As a result, in estimating areal rainfall amounts, Radar- AMeDAS precipitation overestimates AMeDAS measurement by 8% at 5mm/h and by 12% at 40mm/h. Radar- AMeDAS precipitation over the sea, with no local calibration by AMeDAS and with little influence of orography, is 2% weaker in intensity than AMeDAS at 10mm/h, and 12% at 40mm/h.
ER -