How to draw the minimum and maximum sea ice extent on a sea ice concentrations map?

Now, I draw a average sea ice concentrations map during one month （see below）, however, I want to plot a minimum and maximum sea ice extent on this map, what should I do? Can someone help me？

I uploaded a compressed file and want to use the asi-AMSR2-n6250-20160808-v5.4.nc as the average sea ice concentration to draw a map, and then use asi-AMSR2-n6250-20160718-v5.4.nc as the maximum sea ice, draw the maximum range in the figure (dashed outline), and then use asi-AMSR2-n6250-20160905-v5.4.nc as the minimum sea ice, and draw the minimum range in the figure (dashed outline). My code is as follows ：

% input sea ice data
x=ncread('asi-AMSR2-n6250-20160718-v5.4.nc','x');
y=ncread('asi-AMSR2-n6250-20160718-v5.4.nc','y');
z=ncread('asi-AMSR2-n6250-20160718-v5.4.nc','z');

[M,N]=size(z);
lat1=x;
lon1=y';
lat2=repmat(lat1,1,N);
lon2=repmat(lon1,M,1);
[lat,lon]=psn2ll(lat2,lon2);

%plot sea ice map
h=figure('color',[1 1 1]);
set(h,'position',[100,100, 800, 600]);

ax1 = axesm('MapProjection','lambert','MapLatLimit',[65 89],'MapLonLimit',[112 220],'Frame','on','Grid','on','ParallelLabel','on','MeridianLabel','on');

mlabel('PlabelLocation',5,'FontSize',12);

geoshow(ax1,lat,lon,z,'DisplayType', 'texturemap');
geoshow('landareas.shp', 'FaceColor', rgb('tan'));
colormap(ax1,gray);
hcb1 = colorbar(ax1);
set(get(hcb1,'Xlabel'),'String','Sea Ice Concentrations (%)','FontSize',12);
set(ax1,'position',[0.25,0.25,0.7,0.7]);
set(ax1,'Fontsize',14);

[Scott MacKenzie]

It might help if you frame your questions in terms of MATLAB code.

Perhaps provide the data (or a subset of the data) and provide any code you've written thus far in attempting to achieve the desired outcome.

[Rik]

Comment posted as flag by @Bei JIANG:

I update my question.