Temperature inversion occurs when a layer of hotter air sits on top the ground layer indicated as patch in blue in SkewT graph (near the ground). The favorable condition for the vertial mixing is the temperature of the air reduces as the high increased (the ground is the lowest point).
Hodograph: showing the wind speed and direction (in knots (1.85km/h) and direction (in degree) with the color bar in meters)
Observed concentration of fine particulate matter (PM2.5) by a FEM station operated by US Embassy in Hanoi or US Consulate in Ho Chi Minh City