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The development of a coupled model (PCPF-SWMS) to simulate water flow and pollutant transport in Japanese paddy fields 总被引:1,自引:0,他引:1
Julien Tournebize Hirozumi Watanabe Kazuhiro Takagi Taku Nishimura 《Paddy and Water Environment》2006,4(1):39-51
A new coupled model (PCPF–SWMS) was developed for simulating fate and behavior of pollutant in paddy water and paddy soil.
The model coupled the PCPF-1, a lumped model simulating pesticide concentrations in paddy water and 1 cm-surface sediment
compartment, and the SWMS-2D, a finite element numerical model solving Richard's and advection-dispersion equations for solute
transport in soil compartment. The coupling involved improvements on interactions of the water flow and the concentration
the pollutant of at the soil interface between both compartments. The monitoring data collected from experimental plots in
Tsukuba, Japan in 1998 and 1999 were used to parameterise and calibrate hydraulic functioning, hydrodynamic and hydrodispersive
parameters of the paddy soil. The analysis on the hydraulic functioning of paddy soil revealed that the hard pan layer was
the key factor controlling percolation rate and tracer transport. Matric potential and tracer monitoring highlighted the evolution
of saturated hydraulic conductivity (K
S) of hard pan layer during the crop season. K
S slightly decreased after puddling by clay clogging and strongly increased after mid term drainage by drying cracks. The model
was able to calculate residential time in every soil layers. Residential time of tracer in top saturated layers was evaluated
to be less than 40 days. It took 60 days to reach the unsaturated layers below hardpan layer. 相似文献
455.
Satoshi Suyama Kazuhiro Oshima Masayasu Nakagami Atsushi Kawabata 《Fisheries Science》2011,77(2):223-233
We evaluated the seasonal changes in otolith and somatic growth of age-0 Pacific saury Cololabis saira in 223 fish collected between June and November 2002. We calculated the age in days of each individual by measuring otolith
growth increments under a scanning electron microscope. The age was correlated with body length and otolith radius. We also
observed seasonal changes in the rate of increase in body length and otolith radius and in the pattern of otolith growth.
Until August, both body length and otolith radius increased with age. Thereafter, the otolith radius continued to increase,
whereas the rate of somatic growth decreased. As a result, the ratio of otolith radius to body length increased. After August,
the percentage of otoliths with unreadable increments on their edge increased due to the formation of hyaline zones. Otoliths
grew both radially and in thickness until July, but gradually stopped growing in thickness after August. Beginning in October,
more than 80% of otoliths only grew radially. After August, the otolith not only continued growing but the morphological growth
pattern also changed. 相似文献