The frequencies of solar p-modes are known to change over the solar cycle.
There is also recent evidence that the relation between frequency shift of
low-degree modes and magnetic flux or other activity indicators differs bet
ween the rising and falling phases of the solar cycle, leading to a hystere
sis in such diagrams. We consider the influence of the changing large-scale
surface distribution of the magnetic flux on low-degree (l less than or eq
ual to 3) p-mode frequencies. To that end, we use time-dependent models of
the magnetic flux distribution and study the ensuing frequency shifts of mo
des with different order and degree as a function of time. The resulting cu
rves are periodic functions (in simple cases just sine curves) shifted in t
ime by different amounts for the different modes. We show how this may easi
ly lead to hysteresis cycles comparable to those observed. Our models sugge
st that high-latitude fields are necessary to produce a significant differe
nce in hysteresis between odd- and even-degree modes. Only magnetic field d
istributions within a small parameter range are consistent with the observa
tions by Jimenez-Reyes et al. Observations of p-mode frequency shifts are t
herefore capable of providing an additional diagnostic of the magnetic fiel
d near the solar poles. The magnetic distribution that is consistent with t
he p-mode observations also appears reasonable compared with direct measure
ments of the magnetic field.