Abstract:We put forward a new tomography model based on the classical tropospheric tomography model. To begin with, the water vapor densities at the vertexes of voxel are estimated using a non-iterative reconstruction algorithm (NIRA). Then, the humidity information at the center of the voxel is derived from NIRA-results through interpolation method, and as initial value was amended again by an iterative reconstruction algorithm. The combined reconstruction algorithm has the advantage of providing initial values which are high quality and reliable in the iterative reconstruction algorithm. Test results show that its accuracy is better than a single reconstruction algorithm.