The EFFECT OF LAND WIDTH ON LAND-SEA BREEZE
By Using WRF.4.0.3 & NCL
The Circulation Intensity
"The narrower the land width, the weaker circulation intensity occurs."
KST: 2018-06-01_16:00:00
CASE 1
CASE 2
DEFAULT
Cause1. Heat capacity
The maximum wind speed is about 6 m/s in case1, 7 m/s in case2 and 8 m/s in default case. In the three cases, however, the maximum value of wind speed is fixed as 6 on the graph because the wind speed is 2 to 3 m/s, except for 2 p.m. to 6 p.m., when the wind speed is fast.
The heat capacity is shown as Cp=c*m*Δt. Since the difference in the width of the land results in a difference of mass and thus makes a difference of heat capacity, default has the largest heat capacity, followed by case 2 and case 1. The temperature difference between land and sea causes the sea breeze, and in the wide land, during growth, the temperature difference is maintained, so the wind becomes stronger and stronger. Thus, the wind speed of the sea breeze is the largest in the default case and the smallest in case1.
The maximum wind speed is about 6 m/s in case1, 7 m/s in case2 and 8 m/s in default case. In the three cases, however, the maximum value of wind speed is fixed as 6 on the graph because the wind speed is 2 to 3 m/s, except for 2 p.m. to 6 p.m., when the wind speed is fast.
The heat capacity is shown as Cp=c*m*Δt. Since the difference in the width of the land results in a difference of mass and thus makes a difference of heat capacity, default has the largest heat capacity, followed by case 2 and case 1. The temperature difference between land and sea causes the sea breeze, and in the wide land, during growth, the temperature difference is maintained, so the wind becomes stronger and stronger. Thus, the wind speed of the sea breeze is the largest in the default case and the smallest in case1.
Cause2. Collision
KST: 2018-06-01_15:00:00
In case1(Land width = 76km) at 15kst, both sides of sea breezes collide in the middle of the land. If you look at the U-wind graph at 15kst, it is offset by the winds from the east and the west, which are in opposite directions. At the same time, if you look at the wind vector graph, you can find that the wind speed is getting weaker from 15kst to 18kst near the land surface. In case1, the wind speed changes from 5m/s to 3.25 ~ 1m/s after sea breeze collision.
In short, the narrower land width, the more likely it is that the sea breeze will collide, causing the winds in opposite directions to bump against each other. This results in the reduction of wind speed. This can be interpreted as a weakening of the sea breeze circulation because the wind, which is part of the circulation, slows down.