% Template for question 1 of Problem Set 3
% Brian Hornbuckle, January 25, 2011.

clear;

load ivs_2009_air.dat;

doy = ivs_2009_air(:,1);  hhmm = ivs_2009_air(:,2);

time = timeconvert(doy,hhmm,0);

air = ivs_2009_air(:,3);        % third column of data file is air temperature, deg C

rh = ivs_2009_air(:,4);         % fourth column is relative humidity, %

figure(1)

subplot(2,1,1)
plot(time,air);  grid on;
xlabel('day of year'); ylabel('air temperature, \circC');
 

subplot(2,1,2)
plot(time,rh);  grid on;
xlabel('day of year'); ylabel('relative humidity, %');
axis([195 196 70 100]);         % zoom in on day 195
set(gca,'XTick',[195:3/24:196]);        % set x ticks every 3 hours
set(gca,'XTickLabel',{'midnight' '' '6am' '' 'noon' '' '6pm' '' 'midnight'});       % change the tick labels