PR Validation Result
The purpose of TRMM is to measure absolute quantity of rain distribution in high accuracy. So, it is important to validate radar reflectivity by means of comparison with ground radar data, rain measurement network data and so on.
For validation of radar reflectivity, the following ground radars have been used.
- Japanese ground radar such as meteorological radar at Ishigaki Island.
- Rutherford Appleton Laboratory’s ground radar placed in Singapore.
- JAXA’s meteorological radar located in Tibet as a part of GEWEX Asian Monsoon Experiment (GAME), this radar was used at Miyako Island and Kagoshima. And then routine observation using the radar has been performed at Tanegashima.
Moreover, cross-calibration of TRMM data has been performed with sonde data and ground radar data that were acquired simultaneously during the convergence observation of GAME. Additionally, TRMM data is compared with the rain measurement network data of all over Japan using telemeters, and also verified by rainfall data from TMI.
For validation of radar reflectivity, the following ground radars have been used.
- Japanese ground radar such as meteorological radar at Ishigaki Island.
- Rutherford Appleton Laboratory’s ground radar placed in Singapore.
- JAXA’s meteorological radar located in Tibet as a part of GEWEX Asian Monsoon Experiment (GAME), this radar was used at Miyako Island and Kagoshima. And then routine observation using the radar has been performed at Tanegashima.
Moreover, cross-calibration of TRMM data has been performed with sonde data and ground radar data that were acquired simultaneously during the convergence observation of GAME. Additionally, TRMM data is compared with the rain measurement network data of all over Japan using telemeters, and also verified by rainfall data from TMI.
| Validation | - campaign experiments - regular observations using ground radar and rain gauges - compare radar reflectivity factors (Z-factors) and precipitation intensity (R) |
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・IMCET、GAME−Tibet、X−Baiu、etc. ・Japan Meteorological Agency Ishigaki-jima radar (C band) ・X-band radar (JAXA, Nagoya University, Hokkaido University) ・CRL airborne multiparameter radar (CAMPR) (Ku band) |
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| Regular observations ・Japan Meteorological Agency radar, radar AMeDAS, AMeDAS ・MU radar (Kyoto University) ・Rain gauge (Nagoya University) |
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At present, the status of PR is very good, and it was confirmed that error of receiving level was within 1 dB, based on the internal calibration result, ARC data and sea surface scattering data without rain. Moreover, unlike ground radars, bad influence of anomalous spread or clutter is lower and the data is very clean. On the other hand, it was suggested that PR data includes a little error, because weak rain may not be observed due to the limitation of radar sensitivity. Additionally, extremely weak echo was found in clutter, due to the antenna side-robe. However, the reason of these error has been almost investigated, and the clutter may be removed by using the current processing algorithm. According to the above discussion, TRMM data seems to be better quality than data from ground radars.
| Summary |
PR performed very stably for three years. |
- Algorithms ・・ PR Algorithm Flow / Example of PR Output Product
- Standard Products ・・ Samples
- PR Calibration and Validation ・・ Calibration / Validation Result
