Exercise 6: Snow model

Data from the Kassjöån basin in Medelpad, Sweden is used in this exercise. In the file Snow_data.dat you find precipitation [mm], temperature [°C] and depth of the snow pack [mm water equivalent] (measured using a snow pillow). In each line of the file there is data from one day (six columns with year, month, day, precipitation, temperature, snow). 

Simulation of snow accumulation and snow melt

Write a MATLAB program to simulate the accumulation and melting of snow according to the degree-day method. Include storage within the snow pack and refreezing into your snow routine (the snow pack can store water up to 10% of its water equivalent and the refreezing rate for this water is 20 times lower than the melting rate).
Plot both snow pack (simulated and measured) and the amount of water flowing into the soil against time (daily values).
Change the parameter values (degree-day factor, threshold temperature) to fit the simulated snow pack to the observed one.
Discuss the results and how they are influenced by the parameter values!

Some hints for the start :

• Create Your own MATLAB-directory (e.g. 'c:\user\matlab' or x:\user\matlab) 
• Use Anteckningar/Notepad for writing of the program 
• Save your programs to this directory 
• Help MATLAB to find Your program by writing PATH(PATH,'c:\user\matlab') 

Some Matlab functions which you may find useful:

• load
• plot
• axis
• title
• xlabel ylabel
• if .... (else ....) end 
• for .... end
• min 
• max 

Exercise 7

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