By using computer model analyses, the past 72-hour backward trajectory of the air mass reaching Hong Kong is estimated by the Observatory on a daily basis. The daily trajectories are compiled into the Monthly Backward Trajectory Map. The Monthly Map for June 2010 is now available on the following webpage:
As revealed from the figure below, the air masses reaching Hong Kong in the first half of June 2010 mainly followed a route from the northeast, while those in the second half were originated from the South China Sea.
Backward Trajectory of Air Mass reaching Hong Kong in June 2010
For Daily or Seasonal Backward Trajectory Maps, please visit the following webpages: