Modification of the beam mismatch correction algorithm

In August 2001, the orbit of the Tropical Rainfall Measuring Mission (TRMM) satellite has been boosted from the altitude of 350 km to 400 km to extend its life time. The time delay between transmission of pulses and reception from rain/surface echoes occurs by one inter pulse period (IPP) (Takahashi and Iguchi, 2004). Due to this time delay, one pulse transmitted at N - 1th angle bin is received at the receiving time gate of the next angle bin N. So the mismatch occurs between the transmitting antenna beam direction and the receiving antenna beam direction. This causes antenna gain reduction by 6 dB and leakage of rain/surface echo from the N - 1th angle bin to the Nth angle bin. In this paper, the modified beam mismatch correction algorithm is tested numerically, then it´s applied to the standard algorithm of TRMM/precipitation radar to reduce the correction error of the current beam mismatch correction algorithm.