fig, axes = plt.subplots(2,3,figsize = (15,10),constrained_layout=True)
vmin = -1
vmax = 1
p0=axes[0,0].pcolormesh(ds_s1.z_LM_at_end,vmin = vmin, vmax = vmax,cmap = 'RdBu_r')
axes[1,0].pcolormesh(ds_s3.z_LM_at_mid,vmin = vmin, vmax = vmax,cmap = 'RdBu_r')
axes[0,1].pcolormesh(ds_s1.z_LM_at_mean,vmin = vmin, vmax = vmax,cmap = 'RdBu_r')
p1 = axes[0,2].pcolormesh(ds_s1.Xi12_y,vmin = 0, vmax = 2*np.pi,cmap = 'viridis')
axes[0,2].contour(ds_s1.Xi12_y,levels=50,linewidths=0.5,colors='k')
axes[1,1].pcolormesh(ds_s3.z_LM_at_mean,vmin = vmin, vmax = vmax,cmap = 'RdBu_r')
axes[1,2].pcolormesh(ds_s3.Xi32_y,vmin = 0, vmax = 2*np.pi,cmap = 'viridis')
axes[1,2].contour(ds_s3.Xi32_y,levels=50,linewidths=0.5,colors='k')
textposx = 6
textposy = 236
bbox=dict(facecolor='white', edgecolor='none', boxstyle='round')
axes[0,0].text(textposx,textposy,r'a) Strategy 1, $\tilde{\zeta}(\mathbf{x})$ ',bbox=bbox)
axes[0,1].text(textposx,textposy,r'b) Strategy 1, $\overline{\zeta}^\mathrm{L}\,(= \tilde{\zeta}((\boldsymbol{\Xi^{1 \mapsto 2}})^{-1}(\mathbf{x}))$ ',bbox=bbox)
axes[0,2].text(textposx,textposy,r'c) Strategy 1, $\boldsymbol{\Xi^{1 \mapsto 2}}\cdot \hat{\mathbf{y}}$',bbox=bbox)
axes[1,0].text(textposx,textposy,r'd) Strategy 3, $\zeta^*(\mathbf{x})$',bbox=bbox)
axes[1,1].text(textposx,textposy,r'e) Strategy 3, $\overline{\zeta}^\mathrm{L}\,(= \zeta^*((\boldsymbol{\Xi^{3 \mapsto 2}})^{-1}(\mathbf{x})))$',bbox=bbox)
axes[1,2].text(textposx,textposy,r'f) Strategy 3, $\boldsymbol{\Xi^{3 \mapsto 2}}\cdot \hat{\mathbf{y}}$',bbox=bbox)
cbar_ax1 = fig.add_axes([0.035, -0.052, 0.6, 0.05])
cbar_ax2 = fig.add_axes([0.7, -0.052, 0.275, 0.05])
fig.colorbar(p0, cax=cbar_ax1, orientation = 'horizontal',label='Relative vorticity')
fig.colorbar(p1, cax=cbar_ax2, orientation = 'horizontal',label=r'Final $y$-map')
[axes[i,j].axes.set_xticklabels([]) for i in range(2) for j in range(3)];
[axes[i,j].axes.set_yticklabels([]) for i in range(2) for j in range(3)];
[axes[i,j].set_aspect('equal') for i in range(2) for j in range(3)];
fig.savefig('Figure-4.png',dpi=200,bbox_inches='tight')