jgg     2015 35 (4):  547-551    ISSN: 0412-1961  CN: 21-1139/TG Characteristics of Satellite Time-Variable Gravity  Field before M8.1 Nepal Earthquake 1 Key Laboratory of Earthquake Geodesy, Institute of Seismology, CEA, 40 Hongshance Road, Wuhan 430071,China 2 Wuhan Base of Institute of Crustal Dynamics, CEA, 40 Hongshance Road, Wuhan 430071,China 3 School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China Received: 2015-05-18  Revised: null  Online: 2015-07-29 Supporting info