Abstract:

Owing to the vadose zone evaporation water from the ground surface, finding out the bare soil evaporation rule has important meaning to study some vadose zone water and underwater evaporation problems. To find out the rule of bare soil evaporation intensity in northwest arid inland basin,we analyze the vadose zone cross section water flow features with weather data and calculate the bare soil evaporation intensity adopting the finitedifference method through developing some bare soil water content and vadose zone pressure monitoring site experiments. Express as a result: According to vertical transportation different status of some vadose zone water, the cross section in the bare soil area vadose zone is divided into the vadose zone water upward to transfer zone and the vadose zone water downward to move zone. The extreme limit evaporation depth is 1.2 m in the bare soil zone of Northwest arid inland basin. Subjecting to the external space weather evaporation ability and the vadose zone water upward to transfer ability, the bare soil evaporation inside the basin appears in the second half month of April to the second half month of September, among which the bare soil evaporation quantity in the second half month of April to May is the biggest, and the evaporation intensity reaches to 0.56 mm/d on the average. The percentage of the bare soil evaporation intensity only equivalent to surface evaporation intensity on the average of 3.5%, as biggest as 6.7%.

Key words: bare soil, evaporation intensity, total water potential, vadose zone, arid inland basin