Simulated One Point Mode

Revision as of 15:00, 11 January 2019

Simulated One Point Mode

This mode is currently only supported for Mars.

It requires:

1: a Temperature T

2: @ a season ls

3: @ a LTST hour

 OUT = krc(lat = 12., lon = 12., T = 190., ls = 0., hour = 4.)

The output is the equivalent thermal inertia in J m-2 K-1 s-1/2, in this case OUT = 334 Jm-2K-1s-1/2.

The One-Point Mode outputs a TI (SI) for an array of input temperatures with the given parameters

If no soluation can be found, it can output various values that indicate why a TI was not derived for failure cases:

-600: The Temperature provided is lower than the lowest model output. Possible Frost Presence

-500: No value was derived or returned. KRC may have failed to run all together

-400: Negative TI value. This is a non-physical return as a function of the fitting routine

-300: TI value larger than 2200 SI. 2200 SI is the top of the available lookup table and extrapolation is not permitted

-200: Returned TI value doesn't meet proximity criterion (TI_Guess_PCT)

-100: Bad TI_Guess / TI_Guess_PCT combination. This is most likely a user error

To speed up the processing time, the user can provide a TI guess (TI_Guess), and an acceptable tolerance.

Below, the user provides a good guess (300 Jm-2K-1s-1/2 vs. 334 Jm-2K-1s-1/2). The processing time is significantly reduced.

OUT = krc(T=190,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=300.)

If the user provides a poor guess, the output will be wrong, and no flag will be raised (guess is 900 Jm-2K-1s-1/2, KRC returns 641 Jm-2K-1s-1/2 but solution is ~ 334 Jm-2K-1s-1/2).

OUT = krc(T=190,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=900.)

To avoid this situation, set a tolerance (TI_Guess_PCT), in % of the guess within which the solution is deemed acceptable. Here the initial guess is within 20% of the solution, so KRC returns a value (334 Jm-2K-1s-1/2).

OUT = krc(T=190,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=300.,TI_Guess_PCT=0.2)

If the tolerance criterion is not met, a flag is retuned (-200). Here the solution is not within 5% of the guess.

OUT = krc(T=190,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=300.,TI_Guess_PCT=0.05)

Pathological Case; KRC runs, sets TI_Guess to 0., and returns a flag => -100.

OUT = krc(T=190,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess_PCT=0.2)

Below Frost point => -600. (The solution was a negative TI)

OUT = krc(T=130,ls=0.,hour=4.,lat=12.,lon=12.)

Below Frost point, horrible guess but -600

OUT = krc(T=130,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=200.) 

Below Frost point, horrible guess -200    

OUT = krc(T=130,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=200.,TI_Guess_PCT=0.5)

Much too warm => flags high TI => -300.                                                           

OUT = krc(T=500,ls=0.,hour=4.,lat=12.,lon=12.)

Much too warm, poor guess => flags high TI => -300.

OUT = krc(T=500,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=200.)

Much too warm, poor guess => flags poor guess => -200.

OUT = krc(T=500,ls=0.,hour=4.,lat=12.,lon=12.,TI_Guess=200.,TI_Guess_PCT=0.1)

No guess, slow, => 334.

OUT = krc(T=190,ls=000.00,hour=4.,lat=12.,lon=12.)

No guess, slow, => 334.

OUT = krc(T=190,ls=359.99,hour=4.,lat=12.,lon=12.)

Sets DELLS=0. to avoid this issue but error message: Please do not set both DELLS and DELJUL XXX

OUT = krc(T=190,ls=359.99,hour=4.,lat=12.,lon=12.,DELLS=0.)