TY - RPRT AU - K. Onogi BT - ERA-40 Project Report Series C1 - Research CY - Shinfield Park, Reading DA - 08/2000 LA - eng M1 - 2 PB - ECMWF PP - Shinfield Park, Reading PY - 2000 EP - 77 T2 - ERA-40 Project Report Series T3 - ERA Report TI - The long-term performance of the radiosonde observing system to be used in ERA-40 ER -