ESO754

Homework #4

http://yang.gmu.edu/eos754/html/EOS754-Homework-Problem4.htm

The NCEP/NCAR Reanalysis Monthly Mean Subsets for SLP (Sea Level Pressure) values are given in both GRIB and ASCII format. (For more information on this data set, visit the data web page at http://dss.ucar.edu/datasets/ds090.0/. This data is the same data for Problem 2 of HW#1.) Both the GRIB and ASCII data are available at http://yang.gmu.edu/eos754/data/.

Use only December data from 1950 to 2000 (51 months only) to perform PCA (EOF). Please remove the mean values for each grid (pixel) off first from the data. Please report your results by the followings:

1. Display the first two spatial principal components (spatial patterns for EOF₁ and EOF₂). (10 points)

2. Display the corresponding temporal principal components (time series for PC₁ and PC₂). (10 points)

3. Give the corresponding eigenvalues and contribution to the total variance by the first two components. (10 points)

4. Display the scatter plot by using PC₁ and PC₂. (10 points)

5. Limit your spatial coverage area to north of 20^oN and repeat the PCA analysis. Please display the first two spatial principal components only. (10 points)

Submission:

Please submit your results by email to yang@yang.gmu.edu (in one file if you have ZIP feature). The file name should like yourLastName_firstName_HW4 (failure to include identifier for your electronic submission may result in point loss). Your submission should have one file for all answers and your programs. If you used a GUI tool without programming, you should give a short description of the tool (if not a common tool) and your major steps to get the results. Your programs and tool descriptions may be shared with other students after the due day. If you have any concern on the distribution, please let the instructor know.

Post Date: April 16, 2008

Due Date: April 30, 2008

Grade: 50 points total and 10% contribution to the final score.