def gf_var_tsplot(ax, varname, df_qa, df_gf):
    """
    Plot a variable showing what has been gapfilled
    """
    #varname_f = varname + '_f'
    # Plot gapfill data oand overlay qa data
    ax.plot(df_gf.index, df_gf[varname], marker= '.', ls='none',
            color = 'xkcd:neon green', label='Gapfilled')
    ax.plot(df_qa.index, df_qa[varname], marker='.', ls='none',
            color='k', label='Original')    
    ax.set_ylabel(varname)
    ax.legend()

    return ax