yo evert

data2=dlmread('A2vlissingen.txt');
data2=data2(1501:1501+10*12,:);
yv=(data2(:,2)-mean(data2(:,2)))/1000;
year=floor(data2(:,1));
fracyear=data2(:,1)-year;
doy=fracyear*365.24;
d0=datenum(year,01,01,0,0,0)+doy;
plot(d0,yv)
hold on
plot(t,z,'g')
xpts=[datenum(1987,01,01) datenum(1988,01,01) datenum(1989,01,01) datenum(1990,01,01)...
    datenum(1991,01,01) datenum(1992,01,01) datenum(1993,01,01) datenum(1994,01,01)...
    datenum(1995,01,01) datenum(1996,01,01) datenum(1997,01,01)];
set(gca,'XTick',xpts,'XTickLabel',datestr(xpts,'yyyy'));