To identify whether the spatial and temporal distribution of temperature extremes and precipitation extremes has changed in central and eastern China including Henan, Shandong, Anhui and Jiangsu provinces, the spatial and temporal distributions of extreme temperature and precipitation indices trends during 1961–2011 were investigated and analysed. To guarantee the accuracy of trend analysis, daily maximum and minimum surface temperature and daily precipitation from 299 meteorological stations were used. Eight extreme temperature indices and seven extreme precipitation indices were chosen. Mann–Kendall method was used to check the statistical significance of trends, while Sen's nonparametric method was used to calculate the trend magnitudes. The analyses of extreme temperature indices detected significant and stable trends in the majority of the stations, especially for the most part of southern Anhui and southern Jiangsu provinces. The strongly stable downward trends in cold extremes and the strongly stable upward trends in hot extremes were recorded in most of the regions. In contrast, significant and stable positive trends were insignificantly recorded for precipitation extremes in the study area, which predominantly occurred in the southern part of the region. Furthermore, the positive trends were more frequent than the negative trends in most extreme precipitation indices. The results may provide a reference for a more particular knowledge of the climate change in this region and provide guidance for agriculture development.

The porous-fiber module (PFM) is an advanced product used for rainfall regulation and storage. Most studies focus on the characteristics of its constituent material while ignoring the impacts of PFM application on infiltration and runoff. In this study, several factors were comprehensively considered in the field control simulated rainfall experiments conducted on bare land, including two types of rainfall intensities, four PFM volumes, and two arrangements of the PFM, to evaluate the impacts. The experiments consisted of measuring soil water content variation, surface runoff of each treatment plot, and the cumulative infiltration obtained by water balance. The results demonstrated that the effect of PFM volume on infiltration and runoff was much greater than that of the PFM arrangement. The addition of PFM could improve the water-holding capacity of soil; this effect initially strengthened and subsequently weakened with the increase in the PFM volume. The PFM embedding increased the cumulative infiltration of the experimental plots by 5.1-79.2%, delayed the runoff start time by 0-20 min, weakened the peak by 13.6-51.1%, and reduced the runoff-yielding amount by 11.23-62.53%, compared with those of the control plot. These effects were enhanced as PFM volume increased. An empirical formula, presented as the theoretical influence of PFM volume on the product of the cumulative infiltration multiplied by the Philip model derived by the control plot, was further established for simulating the infiltration process with various PFM volumes.

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