We present optical observations and Monte Carlo models of the dust coma , tail , and trail structures of comet 22P/Kopff during the 2002 and 2009 apparitions .
Dust loss rates , ejection velocities , and power-law size distribution functions are derived as functions of the heliocentric distance using pre- and post-perihelion imaging observations during both apparitions .
The 2009 post-perihelion images can be accurately fitted by an isotropic ejection model .
On the other hand , strong dust ejection anisotropies are required to fit the near-coma regions at large heliocentric distances ( both inbound at r _ { h } =2.5 AU and outbound at r _ { h } =2.6 AU ) for the 2002 apparition .
These asymmetries are compatible with a scenario where dust ejection is mostly seasonally-driven , coming mainly from regions near subsolar latitudes at far heliocentric distances inbound and outbound .
At intermediate to near-perihelion heliocentric distances , the outgassing would affect much more extended latitude regions , the emission becoming almost isotropic near perihelion .
We derived a maximum dust production rate of 260 kg s ^ { -1 } at perihelion , and an averaged production rate over one orbit of 40 kg s ^ { -1 } .
An enhanced emission rate , accompanied also by a large ejection velocity , is predicted at r _ { h } > 2.5 pre-perihelion .

The model has also been extended to the thermal infrared in order to be applied to available trail observations with IRAS and ISO spacecrafts of this comet .
The modeled trail intensities are in good agreement with those observations , which is remarkable taking into account that those data are sensitive to dust ejection patterns corresponding to several orbits before the 2002 and 2009 apparitions .