SO503 Honors ResearchMethods

## Spring 2008 Test 2

 Short answer 5 @ 20 points 100 Total 100

Answer 5 of the 6 questions.

1.  Answer both parts of this question. (Two tidal records in the Chesapeake Bay)

One of the graphs above shows an autocorrelation, and the other a cross correlation.  Which is which?  How could you tell, and what is the difference between the two?

The figures above show a portion of the correlogram for an autocorrelation or cross correlation (which of the two does not matter), and the one below shows portions of the two series plotted with two different lags.  Suggest a lag whose correlation in the top diagram could correspond with each of the plots in the lower diagram, and explain why you made these choices.

2.  The two graphs below show cross correlations between two time series.  The series are sampled at monthly intervals.  There are a total of 4 different time series; two for each comparison.

·        According the Nyquist sampling theory, how does the monthly sampling interval affect the results?

·        What two things could you be looking for in this data, and what do the results show for the two comparisons?

·        Are the two results similar or different?

Top:  NAO, BWI temperature anomaly

Bottom: UCAR, OZ estimates of SOI

3.  For the snippet of Matlab code below, explain the purpose of 4 different lines of code.   How much output will this code write?

`time=zeros(12,1);`
`temp=zeros(12,1);`
` `
`…………………… Code omitted`
` `
`for i=1:10,`
`   if heading(i) < 0,`
`     fprintf('%8.3f %12.2f \n',time(i),temp(i));`
`   end`
`end;`

4.  Define 5 of the following 6 terms:

·        Stefan-Boltzmann law

·        Wien's displacement law

·        Image registration

·        Drainage basin

·        Contrast enhancement

·        Hyperspectral imagery

5.  The two graphs below show different ways of analyzing the decline in sea ice extent.  Which do you think will have a higher correlation coefficient, and why?  What will be the sign of the correlation coefficient, and what does that indicate about the relationship?

(monthly variation from 1950 to 2000, plotted as annual fluctuations versus plotted by season)

6.  Discuss the process used by Halpern and others for their paper in Science, and the results they obtained.   What techniques did they use, and what was important enough about the paper to warrant publication in Science?