Tangent Adjoint Mode Technology Of Chinese GRAPES Global Mode

Four dimensional variational data assimilation technology is an important method to enhance the effect of numerical whether forecast, Tangent mode and adjoint mode are the key technology of assimilation system. In order to set up tangent and adjoint mode of GRAPES global four dimensional variation assimilation system, below researches were done based on the multi-scale used GRAPES (Global and Regional Assimilation Prediction Enhanced System) which was developed independently by China.GRAPES_TL and GRAPES_AD of GRAPES global mode were set up based on GRAPES global mode adiabatic dynamics frame and four dimensional adjoint information assimilation theory.Global adjoint dynamic database storing library was designed and checkpoint technology was adopted, which solved the original values' storing and restoring difficult points of GRAPES global adjoint mode.Global semi-implicit and semi-Lagrangian atmospheric model's Ritche computation's continuous tangent and adjoint mode in the physical space was design which solved the problem that denominator come forth to be zero in tangent mode in Ritche computation. Helmholtz Equation's high precision tangent and adjoint mode was set up based on GCR.Different Krylov sub-space method and pre-conditional algorithms library of Helmholtz was set up based on PETSc. Helmholtz equation's tangent and adjoint frame is designed in the PESTc library.