Application of visibility new algorithms on fog event

To improve the visibility calculation accuracy of numerical weather predict model, the paper tries to explore two new visibility calculation methods. Firstly, a multi-element visibility algorithm is established based on air temperature, dew point temperature and relative humidity. Then a visibility fusion method is developed. Verifications show that the calculation accuracy of multi-element visibility algorithm gains an advantage over a single relative humidity method, and the visibility fusion algorithm can describe the regional distribution of fog event. visibility fusion algorithm can overcome the limitation of single visibility algorithm and improves the prediction accuracy of fog.