In this research, we will focus on the adjoint based adaptive observation strategies derived from the Retrospective Optimal Interpolation (ROI). The ROI is a new data assimilation scheme which was derived from the quasi-static variational assimilation (QSVA) algorithm and introduced by Song et al. (2009). The Hessian Singular Vectors (Leutbecher, 2003) and Forecast Sensitivity to Observation (Gelaro et al., 2007) are used as the adaptive observation strategy. To test the accuracy of these methods, experiments are performed with the Lorenz 40-variable model.
Key words: adaptive observation strategy, retrospective optimal interpolation, hessian singular vector, forecast sensitivity to observation, adjoint.