Case studies of springtime fog in Hong Kong

Two typical cases of fog in Hong Kong are documented in this paper. The meteorological conditions leading to the occurrence of fog are examined using observations from ground-based, remote sensing meteorological instruments. An acoustic sounding system and a microwave radiometer were used to monitor the atmospheric boundary layer and nowcast the low visibility weather conditions. The measurements from these instruments provide many interesting observations of both the sea fog and mixing fog, including temperature inversions and changes in the humidity profiles. The skill of the numerical weather prediction models in forecasting fog episodes is also briefly discussed. The global model is found to have skill in predicting the occurrence of low visibility weather up to 2 days in advance. © 2018 Royal Meteorological Society