dydx modifications
By default, musoc determines the spacing in meridional direction, dy, according to zonal grid spacing, dx by dydx:
dxmnut=360.*60./dble(i2t)
dxdeg=dxmnut/60.
dydx=1.
do j=2, j0t
yvdegg(j)=yvdegg(j-1)+1.476-dxdeg*dydx*cos(yvdegg(j-1)*pi_180)
enddo
However, this will generate some problems when it comes to high resolution configuration; at high latitude, dy becomes extremely small. Thus, we change dydx along with latitudes:
dxmnut=360.*60./dble(i2t)
dxdeg=dxmnut/60.
do j=2, j0t
dydx = min( 8.25/(18.*cos(yvdegg(j-1)*pi_180) , 10.)
yvdegg (j)=yvdegg (j-1)+dxdeg*dydx*cos(yvdegg (j-1)*pi_180)
enddo
the modified grid spacing of dy at high latitude: 0.03~0.04deg