function [stats]=f_Tmodes(fn, T, N, idx, M, myrs, ND, ttxt)

%* plot temperature data and climate mode index
%
% fn        figure number
% T         temperature record to plot
% N         column number to plot 
% idx       mode index
% M         column number to plot
% myrs      [2 x 1] containing start and end years for average
% ND        no data value
% ttxt      title text, a string of characters
%
% T_records.mat  data are from the GISTEMP archive
%
% T_*       each temperature record contains 18 columns, temps in deg C
% (:,1)     year
% (:,2:13)  monthly means, Jan, Feb, etc.
% (:,14)    D-J-F  mean
% (:,15)    M-A-M  mean
% (:,16)    J-J-A  mean
% (:,17)    S-O-N  mean
% (:,18)    annual mean
%
% modeindex_records.mat  data are from the NOAA Climate Prediction Center
% 
% AAOindex  32x13   Antarctic, the southern annular mode            
% AOindex   61x13   Arctic, the northern annular mode
%  (:,1)    year
%  (:,2:13) monthly means
%  (:,14)   winter mean, first year is J-F mean


%* use function to compute anomaly and trend

[anom, fep, stats]=f_Tanom(T(:,1), T(:,N), [1951 1980]);

figure(fn)
clf
[AX,H1,H2] = plotyy(T(:,1), anom, idx(:,1), idx(:,M));
set(get(AX(1),'Ylabel'),'String','temperature anomaly (C)') 
set(get(AX(2),'Ylabel'),'String','mode index') 
set(AX(1), 'YColor','r', 'XLim', [min(T(:,1)) max(T(:,1))])
set(AX(2), 'YColor','b','XLim', [min(T(:,1)) max(T(:,1))])
set(H1,'Color','r','marker','.')
set(H2,'Color','b', 'marker','.')
title(ttxt)
xlabel('year')