The watershed flow concentration scheme in the distributed hydrology-soil- vegetation model (DHSVM) is coupled with the mesoscale atmospheric model MM5 version 3.5, in which the Oregen States University land surface model (OSULSM) was involved. The flood event which happened in July 2002 in the upper reaches of Heihe river basin is simulated and the surface flow convergence process is shown with this coupled model. It has been concluded that times water head reaches each place of the basin are different. Water amount at each point is split-flow proportionally as the drops in elevation between it and neighbor points. Large part of the water amount pass away in greater slope direction and small part pass away in smaller slope one. Adding of the slope convergence makes the atmospheric model redistributes the surface water laterally.
We present a sedimentary geochemical record of human perturbation in the watershed and related changes in trace metals (Cr,
Ni, Zn and Pb), phosphorus and abundant rock-forming elements (Al, Fe, K, Mg, etc.) in Chaohu Lake over the past 500 years,
a period spanning historical agricultural expansion and modern economic development. The record exhibited a stable terrestrial
detrital input to Chaohu Lake before ca. 1540 AD, a period with less human perturbation of the watershed, which resulted in
low and constant values of trace metals and phosphorus (TP) concentrations as well as Al, Fe, K, Mg, fine silt (<16 μm), the
chemical index of alteration (CIA) and K/Na ratio. Two periods of successive marked increases in Al, Fe, K, Mg, fine silt,
chemical index of alteration (CIA) and K/Na ratio occurred after ca. 1540 AD and 1950 AD. The former period apparently resulted
from enhanced well-weathered topsoil erosion in the watershed related to the expansion of arable land, and the latter resulted
from further enhancement of human perturbation in the watershed during the modern period. Concentrations of trace metals and
TP were positively correlated with that of the rock-forming elements and fine silt. Trace metal pollution was limited during
1540–1950 AD, according to the low enrichment factors (EFs = 0.8–1.1), when an increase in trace metal concentrations was
also linked to changes in detrital input. In addition to detrital regulation, pollution also contributed to an increase in
TP concentrations (average EF 1.4) during 1540–1950 AD and the average accumulation rate of anthropogenic phosphorus was 87.3 mg m−2 a−1. Anthropogenic phosphorus increased further and Pb and Zn pollution also occurred after 1950 AD, reaching maximum values
after 1980 AD, when the average accumulation rates of anthropogenic Zn, Pb and phosphorus (mainly in the form of NaOH-P) were
242.2, 43.3 and 811.8 mg m−2 a−1, respectively. The increase in phosphorus pollution in recent decades is probably from the domestic sewage sources of Hefei
City and non-point sources related to agricultural utilization of commercial fertilizer, whereas Zn and Pb pollution is probably
derived mainly from industrial sources of Hefei City, as deduced from their spatial variations in the sediments of the river
mouths. 相似文献
The hydrothermal synthesis of AlPO4-n which is a functional material of aluminophosphate, was conducted from two kinds of aluminum dross discharged in an aluminum regeneration factory. The effect of structure-directing agent (SDA) on the formation behavior of AlPO4-n from aluminum dross, the suitable condition to obtain AlPO4-n efficiently, and the pore structure and gas adsorption property were investigated in this study.AlPO4-5 and AlPO4-34 are mainly formed from aluminum dross as a raw material, and it is possible to make AlPO4-5 successfully as a main product by adjusting the amount of triethylamine (TEA) as SDA. The gas adsorption amount with AlPO4-5 is the following order; ammonia > dipropylamine > benzene, and it is found that this order mainly corresponds with the polarity of molecule among them. 相似文献