Latitudinal Variation of Martian Surface Temperature Annual Variation

1
Latitudinal Variation of Martian Surface
Temperature Annual Variation

• Guo, Xin
• Ge151a Class Project
• Advisor Oded Aharonson
• May 28th 2004

2
Outline

• The data and problem
• The model
• The tries to a solution
• The points I try to make
• Possible future work

3
The Data and Problem

• MGS TES data
• Way to grid
• 5 degree in latitude,
• 10 degree in longitude,
• 15 degree in Ls,
• MGS global mapping period 3.78 Ls,
• 3.78415.12
• What is the dip in surface temperature around 180
  Ls ?

4
The Model

• Insolation S on Mars

S0590W/m2 is the solar constant for Mars r is
the distance between Mars and the sun (r bar is
the mean) d is the solar declination T is the
latitude H describe the length of the day S is
a function of Tand Ls
http//www-ccar.colorado.edu/asen5050/projects/pro
jects_2001/benoit/solar_irradiance_on_mars.htm
5
The problem still exists ?

• Model captures a part of the latitudinal
  variation
• But obviously not all of them, esp. the little
  dip at different latitude

6
Preprocess the data

• Make them in period of ONE Martian year
• Interpolation of missing data
• Global dust storm at mapping year 2, Ls180-300

7
FFT (Fast Fourier Transform) IFFT (Inverse Fast
Fourier Transform)
?2p/T, T360Ls

• 0 harmonic, mean
• 1st harmonic, period1 year, annual variation
• N th harmonic, period1/N year

• Second harmonic (sort of) captures the dip

8
Relative (to the mean) Powerof Different Harmonic
9
Another Tryrelative power to the annual variation
10
A little Discussion
11
Conclusion

• Surface temperature is directly related to the
  solar insolation
• Obliquity plays an important role in this
  latitudinal variation
• Dips are (very) roughly caused by the second
  harmonic, i.e. half year period component
• Complete answer might (should) be a cooperation
  of different harmonics and their phases

12
Further Work

• Which are those harmonics that play this game?
• What put those harmonics into this game?
  Topography? Thermal inertia? Underground heat
  sources? Intelligent life using air conditioner
  to make a cool summer?
• Whats special at 10-15N 160-170E? I need a rover
  ?