How well can we measure Earth's Energy Imbalance?

Maria Zita Hakuba1,2, Graeme L Stephens2, Felix W Landerer2, Frank Webb3, Srinivas V Bettadpur4, Byron D Tapley5, Bruno Christophe6 and Bernard Foulon6, (1)Colorado State University, Fort Collins, CO, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States, (3)JPL, Pasadena, CA, United States, (4)Center for Space Research, Austin, TX, United States, (5)Univ Texas Austin, Austin, TX, United States, (6)ONERA Châtillon, Châtillon Cedex, France