  The structure and dynamics of the magnetospheres of the outer planets,
particularly Saturn and Jupiter, have been explored both through remote and
in-situ observations. Interpreting these observations often necessitates
simultaneous knowledge of the solar-wind conditions impinging on the
magnetosphere. Without an available upstream monitor, solar-wind context is
typically provided using models initiated with either the output of
magnetogram-constrained coronal models or, more commonly, in-situ observations
from 1 AU. While 1-AU observations provide a direct measure of solar wind
conditions, they are single-point observations and thus require interpolation
to provide inputs to outer-heliosphere solar-wind models. In this study we test
the different interpolation methods using synthetic 1-AU observations of
time-evolving solar-wind structure. The simplest method is "corotation", which
assumes solar-wind structure is steady state and rotates with the Sun. This
method of reconstruction produces discontinuities in the solar-wind inputs as
new observations become available. This can be reduced by corotating both back
and forward in time, but this still introduces large errors in the magnitude
and timing of solar wind streams. We show how the dynamic time warping (DTW)
algorithm can provide around an order-of-magnitude improvement in solar-wind
inputs to outer-heliosphere model from in-situ observations near 1 AU. This is
intended to build the foundation for further work demonstrating and validating
methods to improve inner-boundary conditions to outer-heliosphere solar-wind
models, including dealing with solar wind transients and quantifying the
improvements at Saturn and Jupiter.
