The EFFECT OF LAND WIDTH ON LAND-SEA BREEZE
By Using WRF.4.0.3 & NCL
The Transition Point of the Land Wind from The Sea Breeze.
"The narrower the land width, the faster transition of sea breeze and land breeze comes because of the difference of heat capacity in each case."
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Case1 : Transition point on 4 - 5 p.m.
KST: 2018-06-01_16:00:00
KST: 2018-06-01_17:00:00
In case1(when the land width is the smallest one), land breeze component is formed right after the accumulated energy’s peak time(4 p.m.). This is because the narrower land width has the smaller heat capacity and cools down quickly.
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Case2 : Transition point on 6 - 7 p.m.
KST: 2018-06-01_18:00:00
KST: 2018-06-01_19:00:00
In case2(Land width=152km), the land breeze is formed 2 hours later than case1. Because the land width is broader than case1, case2 relatively has the larger heat capacity and cools down slowly. Therefore, the initial time that the land breeze is formed is slower than case1. Furthermore, strong U-wind component near the surface would have impeded the initial development of the land breeze.
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Case3 : Transition point on 8 - 9 p.m.
KST: 2018-06-01_20:00:00
KST: 2018-06-01_21:00:00
In default case(when the land width is the largest one), the land breeze is formed 4hours later than case1. Because the land width is broader than case1 and 2, default case relatively has the largest heat capacity and cools down very slowly. Therefore, the initial time that the land breeze is formed is slower than case1 and case2. Furthermore, strong U-wind component near the surface would have impeded the initial development of the land breeze like case2.
With the declination of sun energy with the passing of time, sea breeze lost its momentum and reached to transition stage between 9P.M. ~ 10P.M. [R. Pokhrel et al., 2012]
However, looking at the above three cases, only default results close to theory. The reasons may be explained for the following research:
The thermal forcing over a narrow peninsula or island (width<100 km) is insufficient for developing a deep, well-organized mesoscale circulation, and both sea breeze systems are weak. For landmasses with widths between 100 and 150 km the thermal forcing is strong enough to develop deep systems, and the landmass is still narrow enough so that the two opposite systems converge at the center and produce a region of deep convection. Landmasses>150 km across are too wide for the two opposing systems to reach each other before sunset, and the associated convergence region in the center of the landmass is weakened. [Xian and Pielke,1991]
Therefore, with the exception of default case, it can be analyzed that sea breeze was converted at a faster time because sea breeze was not sufficiently developed due to sea breeze collision.