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151.
152.
Xiaofeng Guo Hongsheng Zhang Ling Kang Jinlin Du Wanbiao Li Yuanjing Zhu 《Environmental Fluid Mechanics》2007,7(5):421-437
Micrometeorological measurements were made over an irrigated rice paddy during the Huaihe River Basin Experiment (HUBEX) in
1999. This study addresses the quality control and gap filling strategy for the heat fluxes with the Bowen ratio energy balance
(BREB) method. It also endeavors to benefit future studies through comparing five methodologies to estimate the net water
exchange. First, a three-step quality control strategy is constructed. Its first two steps guarantee the correct flux directions
and reject suspicious data, respectively. The third step forbids supersaturation by considering the Bowen ratio ranges for
different flux combinations (termed as “scenarios”). The quality-controlled latent heat (LE) and sensible heat (H) fluxes fall in three scenarios, namely I (LE > 0, H > 0), II (LE > 0, H < 0), and IV (LE < 0, H < 0). Second, the Priestley–Taylor evaporation model (PTEM) is applied to fill the gaps of LE, while the energy balance relationship is used to gap-fill H, namely H = R
N
− G − LE (R
N
: net radiation; G: soil heat flux). Central to the success of this strategy is the idea to calibrate the Priestley–Taylor parameter (α) in
a scenario-specific manner. On average, α values are calibrated as 1.20 and 1.35 for scenario I and II, respectively. For
scenario IV, most α values lie in a narrow range, namely from 0.9 to 1.0. Then, α is calibrated as 0.97 to extend the applicability
of the PTEM to condensation (negative LE). The scenario-specific treatment explicitly explains the diurnal variation of α derived without distinguishing the scenarios.
Third, five methodologies are compared in the calculation of net water exchange, including PTEM-gap-filled BREB method (M1),
energy-balance-based eddy covariance method (M2), and three simplified models to estimate LE, respectively as R
N
− H, R
N
− G, and R
N
. A major finding is that G and H have a similar effect of about 3% in the net water exchange. Thus, if either is neglected, the net evaporation should be
slightly lowered to avoid overestimate, by 3% as a rule of thumb from this work. 相似文献
153.
T J. Sauer J. L. Hatfield J. H. Prueger S. D. Logsdon 《Journal of the American Water Resources Association》1998,34(6):1401-1414
ABSTRACT: Transport of agricultural chemicals in runoff and recharge waters from snowmelt and soil thawing may represent a significant event in terms of annual contaminant loadings in temperate regions. Improved understanding of the melt dynamics of shallow snowpacks is necessary to fully assess the implications for water quality. The objective of this study was to measure the energy balance components of a corn (Zea mays L.) stubble field during the melting of its snowcover. Net radiation (Rn), soil (G), sensible (H), and latent (Q) heat fluxes were measured in a field near Ames, Iowa, during the winter of 1994–1995. Energy consumed by melting including change in energy storage of the snowpack was determined as the residual of the measured energy balance. There was continuous snowcover at the field site for 71 days (maximum depth = 222 mm) followed by an open period of 11 days before additional snowfall and a second melt period. The net radiation and snow melt/energy storage change (5) terms dominated the energy balance during both measurement intervals. Peak daily sensible and latent heat fluxes were below 100 W m?2 on all days except the last day of the second melt period. There was good agreement between predicted and measured values of H and Q during the melting of an aged snow layer but poorer agreement during the melt of fresh snow. Both snowpacks melted rapidly and coincident changes in soil moisture storage were observed. Improved estimates of Q and H, especially for partially open surfaces, will require better characterization of the surface aerodynamic properties and spatially-representative surface temperature measurements. 相似文献
154.
155.
Ian Buist 《Spill Science & Technology Bulletin》2003,8(4):341-346
This paper is a summary of the fundamentals that influence the window-of-opportunity for in situ burning of oil at sea. It is a discussion of the variables and factors that influence the capabilities and limitations of in situ burning of oil. This includes the requirements for ignition and sustained burning and the factors that influence the quantity of residue and burn efficiency and the use of emulsion breakers. 相似文献
156.
DDNP废水处理新方法研究 总被引:1,自引:0,他引:1
DDNP是一种重要的起爆药,其生产废水成份复杂,用传统工艺处理难度较大且不经济。鉴于此,经研究总结得出DDNP废水处理新工艺:先用锅炉废烟气蒸发浓缩,再焚烧的方法,即处理了废水,又降低了锅炉烟尘。是一种低成本、低能耗以废治废的经济实用方法。 相似文献
157.
Biomimetic adsorbent named as PHBBMA was prepared from lipophilic poly-3-hydroxybutyrate (PHB) by a modified double emulsion solvent evaporation method. PHBBMA, characterized by using scanning electron microscope and nitrogen adsorption/desorption measurements, is porous spherical particles. The characterization with the thermal gravimetric analysis and differential scanning calorimetry, 1 H nuclear magnetic resonance and Fourier transform infrared spectroscopy showed that PHBBMA preparation was a physical process without chemical reaction. The adsorption of PHBBMA for o-nitrochlorobenzene (o-NCB) was fitted better by Langmuir model than by Freundlich model, while the pseudo second-order model fitting was better than the pseudo first-order model fitting. The maximal adsorption capacity of PHBBMA for o-NCB was 57.83 mg/g at 30°C, although its specific surface area (S BET ) was only 8.45 m 2 /g. PHBBMA is a safe and environmental friendly adsorbent with high adsorption capacity because its component is innocuous and biodegradable PHB produced reusing wastes and contaminants, no byproduct can produced, and its ester and hydrocarbyl groups have strong affinity with organochlorine compounds. The further work will focus on the modification and improvement of PHBBMA in order to increase its S BET and adsorption capacity. 相似文献
158.
S. N. Kaul T. Nandy C. V. Deshpande A. Srivastava S. Shastry L. Szpyrkowicz 《毒物与环境化学》2013,95(1-2):247-257
An attempt has been made to present the data relating to full scale application of evaporation‐incineration technology for containment of wastewater emanating from H‐acid (mono sodium salt of 1 amino‐8‐hydroxynapthalene 3,6‐disulphonic acid) production with recourse to zero wastewater discharge. The wastewater is acidic with high concentrations of COD and total dissolved salts and BOD/COD ratio of 0.11. NOx, SOx, SPM and CO from stack emissions are within the standards stipulated by the statutory bodies. 相似文献
159.
R. P. Rudra W. T. Dickinson H. R. Whiteley J. D. Gayner G. J. Wall 《Journal of the American Water Resources Association》2000,36(3):585-594
ABSTRACT: The importance of evaporation in hydrologic modeling has been investigated by analysis of water budget at various scales and application of a water management model at plot scale. The data at all scales indicate that evaporation constitutes a major hydrological output. Accurate determination of watershed evapotranspiration depends upon appropriate accounting for the various components of evapotranspiration and their areal and temporal variability. An application of a water management model has revealed that the ranking of the sensitivity of input parameters depends upon the method of determination of evapotranspiration. 相似文献
160.