Uranus flux model too simplistic

[JamieStevens]

While trying to perfect the 1934-638 flux model at mm frequencies, we noticed that the flux of 1934 at 12mm was significantly higher than that recorded by Sault in the current miriad model. After investigation by Wieringa, a paper was found describing long-term variations in the microwave brightness temperature of Uranus. This paper can be found at ​http://dx.doi.org/10.1016/j.icarus.2006.04.012

This not only complicates the process of finalising our 1934 flux model, it means that any flux calibration relying on Uranus may be incorrect. A new model that incorporates Uranus' changing brightness temperature should be implemented.

[MarkCalabretta]

The Miriad planetary routines make no allowance for time variability. This will require changing the argument list of PLTBS (in subs/planet.for) and modifying the five tasks that use it. That would be the first step.

However, it is not clear exactly what time variability should be implemented for Uranus. I would be inclined to take a conservative approach and use a sinusoidal variation of period 84 years and amplitude approx 10K (5%) as shown by the solid line in Fig. 3 of Klien & Hofstader (2006). Is this what you had in mind?

What about the frequency dependence of the variability? Do we assume that it simply scales from that at 3.5cm, i.e. 5%?

[JamieStevens]

I have found two papers that I think I can get a good quality Uranus temperature model from, and that is the focus of my work at the moment.

These papers are: ​http://fr.arxiv.org/abs/1001.4731 (Calibration of Uranus by WMAP against CMB at all ATCA mm frequencies) ​http://adsabs.harvard.edu/abs/2008A%26A...482..359K (Calibration of Uranus by IRAM at 90 GHz, taking into account Uranus pole orientation)