Based on variational adjoint methods, theoretical analyses and numerical experiments are performed for retrievals of two-dimensional winds and related parameters from single-Doppler radar data in polar coordinates. In the method, the reflectivity conservation equation is used as the goving equation and the mass continuity equation as a weak constraint. At the same time, the stable functional of regularization and background field are also introduced in the cost functional. Based on the ideal experiments with artificial data, real two-dimensional wind fields are retrieved with low-altitude data from the Nanjing Doppler Radar Station, and the results are encouraging and promising.