干旱区生态环境知识资源中心

Knowledge of the mechanisms of water infiltration in sand dunes and wadis is the key to understanding the hydrological conditions in arid and semiarid regions. in order to trace infiltration processes in sand dunes, two sites were chosen in Al Ain, United Arab Emirates. An artificial rainfall infiltration experiment was conducted at one site. The other was left in its natural state. The variations in temperature between the sites were compared with soil water tension as well as soil water content at the same depths. Field observations showed that the temperature of the sand dune at the experimental site was more greatly affected by air temperature than that at the natural site, which means that the temperature distribution in the sand dune is closely related to the water content. The vertical distribution of temperature correlated well with the water movement in the sand dune. from which the average velocity of infiltration has been estimated as 3 cm h(-1). The results showed that water infiltration in sand dunes is not continuous but stepped, and suggested the possibility of tracing water movement in sand dunes using temperature.