EVAPOTRANSPIRATION OF LOW-LYING PRAIRIE WETLAND IN MIDDLE REACHES OF HEIHE RIVER IN NORTHWEST CHINA

1 IN T R O D U C T IO NW aterbalance and interactions are foundation to utilizew aterresources rationally in arid inland river basins inC hina (W U etal.,2005).W ateravailability in those ar-eas m ay be the m ain constraint to poverty alleviation,publiche…     

Geochemical behavior of rare earth elements in hydrothermally altered rocks of the Kuroko mining area,Japan

In this study we analyzed the chemical composition of hydrothermally altered dacite and basalt from the Kuroko mining area, northeastern Honshu, Japan, by REE (rare earth element). Features of rare earth element analyses include: (1) altered footwall dacite exhibits a negative Eu anomaly compared with fresh dacite, suggesting preferential removal of Eu²⁺ from the altered dacite via hydrothermal solutions, (2) altered hangingwall dacite and basalt and dacite and basalt adjacent to ore deposits exhibit positive Eu anomalies compared with fresh dacite and basalt, suggesting addition of Eu²⁺ from hydrothermal solutions, (3) LREE ratio (∑LREE/∑REE) from altered dacite of chlorite–sericite zone and K-feldspar zone show a negative relationship with δ¹⁸O, and La/Sm ratios show a positive correlation with the K₂O index. These trends indicate the addition of light rare earth elements such as La to the altered dacite from hydrothermal solution and/or leaching of heavy rare earth elements such as Sm and Yb, (4) Principal component analysis (PCA) indicates that light rare earth elements enrichment is related to the formation of sericite zone near the Kuroko deposits but not to the formations of chlorite and K-feldspar zones, and (5) The correlations among REE features (LREE ratio, MREE ratio, HREE ratio, Eu/Eu?), δ¹⁸O and K₂O index are not found for montmorillonite zone, mixed layer clay mineral zone and mordenite zone. Therefore, it is inferred that sericite, chlorite and K-feldspar alterations are related to the Kuroko and vein-type mineralization, but montmorillonite and mordenite alterations are not related to the mineralizations, and probably they formed at the post-mineralization stage.     

Effects of clear-cutting,meteorological, and physiological factors on evapotranspiration in the Kamabuchi experimental watershed in northern Japan

This study investigated the effects of clear-cutting and the meteorological and physiological factors on forest evapotranspiration (ET), by using the water-budget method in the Kamabuchi experimental watershed (KMB; 38° 56′ 21″ N, 140° 15′ 58″ E) in northern Japan. Meteorological and discharge data collected during no-snow periods (from June to October) from 1939 were used to compare ET in three sub-watersheds: No. 1, where the forest had been left undisturbed, and No. 2 and No. 3, where Cryptomeria japonica was planted after clear-cutting. Paired watershed experiments revealed that clear-cutting caused ET to decrease by approximately 100 mm yr⁻¹, and this reduction continued for more than 20 years, even after C. japonica was planted. ET fluctuated similarly across all watersheds, regardless of clear-cutting or planting. This fluctuation is mainly caused by solar radiation and temperature. Intrinsic water-use efficiency (iWUE) calculated using δ¹³C of tree-ring cellulose in C. japonica increased due to elevated atmospheric CO₂ concentration. We estimated annual carbon fixation in a single tree as the annual net photosynthesis (A). Subsequently, transpiration (E) was calculated from the relationship between iWUE and A. The results showed that A and E per tree increased as the tree grew older; however, the trees' responses to increasing c_a suppress the increase in ET. Moreover, the fluctuation of ET from the watershed was small compared to the fluctuation of P during the observation periods because the increase and decrease in E and interception loss complemented each other.     

Trace Fossils and Sulfur Isotopes in Mudstones around the Kuroko Deposits in the Hokuroku Basin, Northeast Japan: An Attempt to Delineate the Depositional Environment

Abstract. A comprehensive investigation was carried out on the distribution of both trace fossils and sulfur isotopes in mud-stones in the Hokuroku district, northeast Japan, in the hope of delineating the depositional environment of the mudstones in which the Kuroko deposits are embedded. The mudstones are generally massive in structure and usually contain large trace fossils, being indicative of an aerobic biofacies. On the other hand, some mudstones in and above the Kuroko ore horizon are partly laminated and usually contain smaller trace fossils, being assignable to an anaerobic or dysaerobic biofacies. The δ³⁴S values of sulfides in the mudstones above and below the ore horizon range from -40 to -12 %o, indicating mostly oxic depositional conditions in equilibrium with the inferred aerobic biofacies. In the mudstones in the ore horizon, the δ³⁴S values exhibit regionally discriminated variations: -44 to -12 %o in areas far (>1 km) from the known Kuroko deposits and -24 to +6 %o in areas closer to them. The latter high δ³⁴S group implies the temporal occurrence of local anoxic basins in the vicinity of the known Kuroko deposits. At the time of late Nishikurosawa Stage (i.e. the currently assumed Kuroko metallogenic epoch), an intense oceanic stagnation is suggested to have taken place to form the local anoxic basins responsible for the formation and preservation of Kuroko deposits. This oceanic environmental event is considered to be most likely due to increasing biological productivity primarily triggered and enhanced by upwelling of NADW in the paleo-Sea of Japan at that time.     

Aerodynamic Parameters of Regular Arrays of Rectangular Blocks with Various Geometries

The aerodynamic effects of various configurations of an urban array were investigated in a wind-tunnel experiment. Three aerodynamic parameters characterising arrays—the drag coefficient (C _d ), roughness length (z _o) and displacement height (d)—are used for analysis. C _d is based on the direct measurement of the total surface shear using a floating element, and the other two parameters are estimated by logarithmic fitting of the measured wind profile and predetermined total drag force. The configurations of 63 arrays used for measurement were designed to estimate the effects of layout, wind direction and the height variability of the blocks on these parameters for various roughness packing densities. The results are summarised as follows: (1) The estimated C _d and z _o of the staggered arrays peak against the plan area index (λ _p ) and frontal area index (λ _f ), in contrast with values for the square arrays, which are less sensitive to λ _p and λ _f . In addition, the square arrays with a wind direction of 45° have a considerably larger C _d , and the wind direction increases z _o/H by up to a factor of 2. (2) The effect of the non-uniformity of roughness height on z _o is more remarkable when λ _f exceeds 20%, and the discrepancy in z _o is particularly remarkable and exceeds 200%. (3) The effect of the layout of tall blocks on C _d is stronger than that of short blocks. These results indicate that the effects of both wind direction and the non-uniformity of the heights of buildings on urban aerodynamic parameters vary greatly with λ _p and λ _f ; hence, these effects should be taken into account by considering the roughness packing density.     

Radiometrically determined skin temperature and scalar roughness to estimate surface heat flux. Part I: Parameterization of radiometric scalar roughness

A series of experiments carried out in a pasture field during a growing season, allowed a radiometric determination of the scalar roughness for sensible heatz _oh,r . The values ofz _oh,r are shown to vary over the range of 10^–1–10^–7m both diurnally and seasonally, and an existing theoretical model for the estimation of scalar roughness for sensible heat is found to be inappropriate for the precise estimation ofz _oh,r . To parameterizez _oh,r better, a multiple regression analysis was performed, with predictor candidates such as solar elevation, solar radiationR _s , leaf area index LAI, canopy height, the ratio of the solar radiation and the extraterrestrial radiationR _s /R _e , the ratio of the direct and the total solar radiationR _d /R _s , and the roughness Reynolds number among others. The best regression equation which usesR _s , LAI,R _s /R _e , andR _d /R _s is derived withr=0.75; with smaller numbers of predictors, values ofr tend to deteriorate gradually down tor=0.52 when only one predictor, LAI, was incorporated into the equation.     

Energy Balance of Irrigated Intercropping Field in the Middle Reaches of Heihe River Basin

1 Introduction Most of the solar radiation that ecosystem seizes is con- sumed on latent, sensible and soil heat flux. Among them, latent heat flux shares the biggest part (Gutierrez and Meizer, 1994; Ham et al., 1991; Rachidi et al., 1993). The radiation budget and the energy balance are crucial to water conversion and effective water utilization. Also, they are important parts of research of water-saving ag- riculture (Mo et al., 1997). At present, the researches on radiation budget and e…