In this modified code, we are first using the min and max methods to find the ssta variable's minimum and maximum values, across both datasets. The colour limits for both colour bars are then set to these minimum and maximum values using the caxis function. By doing this, the colour scale for both colour bars can be maintained.
figure(1)
set(gcf, 'color', 'w', 'Units', 'Normalized', 'OuterPosition', [0.1 0.1 0.8 0.5]);
% Determine the maximum and minimum values of the ssta variable in both datasets
caxis_min = min([min(ssta_97_1(:)), min(ssta_00_1(:))]);
caxis_max = max([max(ssta_97_1(:)), max(ssta_00_1(:))]);
subplot(1,2,1)
contourf(lon_97_1,lat_97_1,ssta_97_1,'linecolor','k')
colorbar
caxis([caxis_min, caxis_max]); % Set the color limits for the first color bar
xlabel('Longitude(^o)');
ylabel('Latitude(^o)');
subplot(1,2,2)
contourf(lon_00_1,lat_00_1,ssta_00_1,'linecolor','k')
colorbar
caxis([caxis_min, caxis_max]); % Set the color limits for the second color bar
xlabel('Longitude(^o)');
ylabel('Latitude(^o)');
