def compute_diffs(df_dict, df_str, gridclimname1, gridclimname2, prefix1,
    prefix2='meanmonth', comp_dict=None):
    """
    Compute difference between monthly means (e.g,. Temp) for two different gridded datasets (e.g., Liv, WRF)
    """
    if isinstance(comp_dict, type(None)):
        comp_dict = {}
    for each1 in prefix1:
        for each2 in prefix2:
            diffs = df_dict['_'.join([each2, each1, gridclimname1])] - df_dict[
                '_'.join([each2, each1, gridclimname2])]
            comp_dict['_'.join([str(each1), df_str])] = diffs
    return comp_dict
