计算次网格湍流扩散的水平扩散系数 in the Arakawa C grid。 采用形变方法计算水平扩散系数，参考 Smagorinsky (1963)。
Smagorinsky J. General circulation experiments with the primitive equations: I. The basic experiment[J]. Monthly weather review, 1963, 91(3): 99-164.
可以让评估更加平滑
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| real(kind=fp), | intent(in) | :: | dt |
积分时间: s |
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| real(kind=fp), | intent(in) | :: | dx(:,:) |
x方向长度: m |
||
| real(kind=fp), | intent(in) | :: | dy(:,:) |
y方向长度: m |
||
| real(kind=fp), | intent(in) | :: | u(:,:) |
纬向风 u-stag: m/s |
||
| real(kind=fp), | intent(in) | :: | v(:,:) |
经向风 v-stag: m/s |
||
| real(kind=fp), | intent(out) | :: | kx(:,:) |
horizontal diffusion coefficient in x: m^2/s |
||
| real(kind=fp), | intent(out) | :: | ky(:,:) |
horizontal diffusion coefficient in y: m^2/s |
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| real(kind=fp), | intent(in), | optional | :: | area |
传入全局平均面积，避免重复计算: m^2 |