The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) built the rainfall observation network composed of 38 X-band dual polarimetric radars called XRAIN. The results of verifying the accuracy of the XRAIN rainfall, attenuation correction caused underestimation of radar rainfall distant from radar, and that underestimation caused underestimation of the compositing rainfall close to radar. The method of attenuation correction was modified to correct for attenuation of the almost all intensity of rainfall. The compositing rainfall processing was modified to add the weighting function related to the distance from radar. Modifying of attenuation correction and compositing rainfall processing improved underestimation of XRAIN rainfall.
