An evolving synoptic magnetic flux map and implications for the distribution of photospheric magnetic flux

We describe a procedure intended to produce accurate daily estimates of the magnetic flux distribution on the entire solar surface. Models of differen tial rotation, meridional flow, supergranulation, and the random emergence of background flux elements are used to regularly update unobserved or poor ly observed portions of an initial traditional magnetic synoptic map that a cts as a seed. Fresh observations replace model estimates when available. A pplication of these surface magnetic transport models gives us new insight into the distribution and evolution of magnetic flux on the Sun, especially at the poles where canopy effects, limited spatial resolution, and foresho rtening result in poor measurements. We find that meridional circulation ha s a considerable effect on the distribution of polar magnetic fields. We pr esent a modeled polar field distribution as well as time series of the diff erence between the northern and southern polar magnetic flux; this flux imb alance is related to the heliospheric current sheet tilt. We also estimate that the amount of new background magnetic flux needed to sustain the `quie t-Sun' magnetic field is about 1.1x10(23) Mx d(-1) (equivalent to several l arge active regions) at the spatial resolution and epoch of our maps. We co mment on the diffusive properties of supergranules, ephemeral regions, and intranetwork flux. The maps are available on the NSO World Wide Web page.