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We present optical observations and Monte Carlo models of the dust coma,tail, and trail structures of comet 22P/Kopff during the 2002 and 2009apparitions. Dust loss rates, ejection velocities, and power-law sizedistribution functions are derived as functions of the heliocentric distanceusing pre- and post-perihelion imaging observations during both apparitions.The 2009 post-perihelion images can be accurately fitted by an isotropicejection model. On the other hand, strong dust ejection anisotropies arerequired to fit the near-coma regions at large heliocentric distances (bothinbound 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 mostlyseasonally-driven, coming mainly from regions near subsolar latitudes at farheliocentric distances inbound and outbound. At intermediate to near-perihelionheliocentric distances, the outgassing would affect much more extended latituderegions, the emission becoming almost isotropic near perihelion. We derived amaximum dust production rate of 260 kg s$^{-1}$ at perihelion, and an averagedproduction 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>$2.5pre-perihelion.  The model has also been extended to the thermal infrared in order to beapplied to available trail observations with IRAS and ISO spacecrafts of thiscomet. The modeled trail intensities are in good agreement with thoseobservations, which is remarkable taking into account that those data aresensitive to dust ejection patterns corresponding to several orbits before the2002 and 2009 apparitions.

Comet 22P/Kopff: Dust environment and grain ejection anisotropy from visible and infrared observations