Fig.1

Three-dimensional topography within a radius of 40 km from the observed area"

Table 1

Performance indicators for observation equipment"

Table 2

P-T method for stability classification"

Table 3

An improved stability classification table using solar radiation or night net radiation and wind speed values"

Table 4

Atmospheric stability classification (temperature gradient method)"

Table 5

Classification of atmospheric stability(combined method of temperature gradient and wind speed ΔT-U)"

Table 6

Classification standard of coastal area by Ri method"

Table 7

Frequency of occurrence of atmospheric stability for four classification methods in the observed area in 2018 %"

Fig.2

Occurrence frequency of different atmospheric stability based on four classification methods during spring (a), summer (b), autumn (c), and winter (d) in 2018"

Fig.3

Occurrence frequency of different atmospheric stability based on solar radiation method(a), temperature gradient method(b), ΔT-U method (c), and Ri method (d) in 2018"

Fig.4

Annual mean profiles of wind speed (a) and air temperature (b) in the observed area in 2018"

Fig.5

Daily variation of occurrence frequency of each stability under four classification methods solar radiation method(a), temperature gradient method(b), ΔT-U method (c), Ri method(d), in the observed area in 2018"

Fig.6

The occurrence frequency of various kinds of stability under different flows in the observed area in 2018, based on ΔT-U method (a)、Ri method(b)"