Simulating saturation‐excess surface run‐off in a semi‐distributed hydrological model

The level of complexity, and the number of parameters, to include in a hydrological model is a relatively contentious issue in hydrological modelling. However, it can be argued that explicitly representing important run‐off generation processes can improve the practical value of a model's outputs. This paper explores the benefits of including a new function into an existing semi‐distributed hydrological model (the Pitman model) that is widely used in the sub‐Saharan Africa region. The new function was designed to represent saturation‐excess surface run‐off processes at subcatchment scales and was motivated by the evidence of dambo (low topography riparian areas) type features in many sub‐Saharan river basins. The results for uncertainty versions of the model, with and without the new function, were compared for 25 catchments, which were divided up into those where evidence of dambos exists and those where there is no such evidence. The results suggest that the new function certainly improves the model results for the catchments where dambos exist, but not in situations where saturation‐excess surface run‐off is not expected to occur. The overall conclusion is therefore that the addition of the new function is justified.     

An Environmental Threshold of Soil Test P and Degree of P Saturation of Brazilian Oxisols

To develop P management guidelines for poultry litter application in Oxisols of Brazil, the relationship between water soluble P (WSP), soil test P (STP), and degree of P saturation (DPS) needs to be established. The study examined this relationship in Oxisols of Brazil receiving poultry litter. Soils were analyzed for Mehlich‐1 P (M1‐P), WSP, P fractions, P sorption index (PSI), and P saturation based on Mehlich‐1 extractable P, Al, Fe (DPS_M1), and PSI (DPS_PSI). Surface water bodies in the catchment area were examined for inorganic and total P. All the surface water bodies in the catchment area of the sampled plots were highly enriched in inorganic and organic P. Enrichment of soil P fractions following poultry litter application followed the order HCl‐bound > NaOH‐bound > NaHCO₃‐bound fraction. M1‐P was correlated to labile (NaHCO₃‐P_i), and stable P pools (NaOH‐P and HCl‐P) and reflected the cumulative P accumulation in these soils. P saturation indices increased with cumulative P addition and increasing M1‐P. WSP increased with increasing DPS and a change point was noticed at 23% DPS_PSI (equivalent to DPS_M1 of 16.5%) corresponding to M1‐P of 44.5 mg P kg^?1, which could be regarded as threshold for P loss in these soils.     

BP 模型在南海神狐海域天然气水合物储量参数预测中的应用

在用测井数据预测储量参数方法的基础上,采用BP 神经网络法预测天然气水合物储量参数( 孔隙度、饱和度) 。选取一口有实测值的井,将其测井数据作为样本数据,建立网络模型,由其他井的测井数据输入此模型得到储量参数预测结果。经过实践检验此模型得出的结果比经验公式法更精确。     

塔里木盆地奥陶系礁灰岩CO2毛细残余封存能力实验研究

实施CO2地质封存是目前公认的减少温室气体排放的有效方法。在可能进行封存的场所中,咸水含水层封存潜力最大,机理也最为复杂。其中毛细残余封存机理在封存量和封存安全性方面均具有十分重要的意义。在评价毛细残余封存量时,残余气饱和度是一个十分重要的参数。文中提出了测定残余气饱和度的实验方法,并实际应用于中国塔里木盆地奥陶系礁灰...     

陕西华清池温泉热储温度的估算

本文以华清池泉水化学成分为例,采用水—岩化学平衡计算的方法,进行了热储温度估算。根据9种矿物平衡温度的统计结果,得出华清池温泉深部热储温度为53.44±6.11℃。这和温泉附近几个热水孔的温度测定结果是基本一致的。     

Effect of anthropogenic CO2 on the pH and the saturation states of calcite and aragonite of seawater

Growth of phytoplankton, zooplankton and probably most other marine organisms as well, is likely to be affected by the pH of seawater. Growth of calcareous shells and skeletons is less likely to be affected by the saturation states of calcite and aragonite but the dissolution is. The increase of CO₂ in the oceans due to burning of fossil fuel and clearing of forests is decreasing the pH of seawater and the degrees of saturation for calcite and aragonite wordwide. This paper presents the results of the first attempt to estimate the vertical distribution of anthropogenic CO₂, and the decreases in pH and the degrees of saturation of calcite and aragonite in seawater near Taiwan. Most effects are very small except for the possible dissolution of aragonite on the upper continental slope starting around 2050 AD.     

单元路网长度的DMSP/OLS夜间灯光数据去饱和方法

近年来DMSP/OLS夜间灯光数据被广泛应用到人类活动强度及城市化进程的研究中,但由于OLS传感器的限制导致,在夜间灯光强度过高的城市中心区,NTL数据存在较为明显的饱和现象。这种饱和现象直接掩盖了城市中心区内部的灯光差异、细节,限制了DMSP/OLS数据在城市中心区的应用。目前缓解灯光数据饱和的方法主要分为:辐射定标法和非辐射定标法。其中辐射定标法虽精度较高,但定标算法复杂,干扰因素多,目前只有部分定标产品;非辐射定标法利用辅助数据(包括自然因素指标、社会经济指标)构建函数模型,对饱和区稳定灯光数据进行去饱和处理,具有较好修正效果。本文在总结VANUI(基于NDVI所构建)、EANTLI(基于EVI所构建)等去饱和指数的基础上,利用地理探测器对NDVI、EVI和UNL(单元路网长度)进行因子探测,量化对稳定灯光数据的解释力,提出了UNLI指数。为了验证UNLI、EANTLI及NTL数据之间的差异,通过"饱和区灯光强度细节刻画程度"、"UNLI、EANTLI与辐射定标数据RCNTL相关性分析"、"耗电量及GDP等经济指标回归拟合优度"3个方面进行比对分析,可以看出:(1)UNLI、EANTLI在修正过饱和灯光数据上均有较好的效果,但UNLI对饱和区灯光强度差异的刻画更加准确;(2)UNLI较之VANUI、EANTLI,可以突破空间分辨率的限制,增加灯光强度细节差异;(3)在灯光强度最高的饱和区,UNLI在与RCNTL的相关性最高,但随着灯光强度的减弱,UNLI、EANTLI与RCNTL的线性回归判断系数R~2逐渐接近,UNLI与RCNTL相关性优势正逐渐丧失;(4)在对耗电量、GDP的拟合分析中,引入UNLI指数的"EANTLIUNLI"的分段式修正模型,充分发挥EVI、UNL各自的优势,具有最优的拟合效果(R~2)_(Adj)=0.873)。实验结果表明,本文引入的修正夜间灯光饱和方法,能够有效的缓解城市中心区的灯光数据饱和问题,并在细节刻画和空间分辨率上有较为明显的提升,可以更精确的从灯光强度的角度反映城市结构的特征。     

饱和度对泥质粉砂岩冻结力学性质的影响

饱和度对泥质粉砂岩常温下力学性质的影响已多有讨论,但对其冻结状态下力学性质的影响尚不明确。对6种饱和度（0%、20%、40%、60%、80%、100%）的泥质粉砂岩样品冻结前后的纵波波速、核磁共振T₂谱、冻结状态下的抗拉强度和点荷载强度进行了测试,试验结果表明：（1）冻结状态下,随饱和度的增加,纵波波速呈现先降低后升高的趋势;（2）在-20℃下,完全饱和样品内部孔隙水有49.2%保持未冻,60%饱和度的样品有81.4%未冻,而20%饱和度样品有87.4%的孔隙水没有冻结;（3）冻结状态下岩样的抗拉强度和点荷载强度随初始饱和度的增加均呈现减小-增加-减小的趋势,在饱和度80%左右均有一极大值,且两个强度的最大值均不出现在饱和度100%时。分析后发现,在低饱和度的状态下,冻结岩石的强度仍取决于孔隙中的未冻水含量;而在高饱和度的区间,孔隙冰的含量决定了其冻结强度;对于接近饱和的岩石,其冻结强度还受到冻胀损伤的影响。     

Modeling the spatiotemporal dynamics of electric power consumption in Mainland China using saturation-corrected DMSP/OLS nighttime stable light data

Obtaining timely and accurate data on the spatiotemporal dynamics of electric power consumption (EPC) is crucial for the effective utilization of electric power in China. The Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) nighttime stable light (NSL) data have good potential for estimating EPC effectively at large scales. However, saturated lighted pixels contained within the NSL data limit the accuracy of EPC estimation. We developed a new method to correct the saturated lighted pixels, using the SPOT VEGETATION (SPOT/VGT) 10-day synthesis product (S10) normalized difference vegetation index (NDVI) data and then modeled the spatiotemporal dynamics of EPC in Mainland China from 2000 to 2008. The results demonstrated the reliability of our approach with an average R value of 0.93 (P<0.001) and an average relative error of ?28.92%. EPC in Mainland China showed an average annual growth rate of 13.46% during the study period from 1198.23 billion kWh in 2000 to 3290.51 billion kWh in 2008. EPC in Mainland China also showed clear regional variation. Northern coastal China and eastern coastal China consumed 37.61% of the total EPC in Mainland China, with only 25.96% of the population and 6.11% of the area.     

Characterization of Continental Intercalaire aquifer (CI) in the Tinrhert-East Area-Illizi Basin on the Algerian-Libyan Border

This paper addresses the characterization of the Continental Intercalaire aquifer (CI) in the Tinrhert-East area of Illizi Basin on the Algerian-Libyan border, which belongs to the SASS1 system, one of the biggest transboundary aquifers in the world. This study concerns a superficies of 4 300 km2. On the basis of Mud Logging borehole data conducted in this part of the aquifer, a realistic characterization of the aquifer was done. The thickness of the CI aquifer varies from 300 m in the south to 700 m in the north, and the depth ranges from 180 m to 320 m. The interpretation of the logs showed that the aquifer is characterized by a maximum net thickness in its southwestern part (more than 600 m), the porosity is very high, ranging from 30% in the west to 24% at the Libyan borders, the permeability is low to medium around 10-5 m/s, and the maximum transmissivity values of about 8×10-3 m2/s were recorded at the center of the study area. The depth of water varies from 235 m to 312 m, and the water flows from south to north, in accordance with the general direction observed in the CI aquifer in the Northern Sahara Aquifer System (SASS). The porosity values obtained from the interpretation of the sonic and density logs permit to estimate the water reserves of this aquifer considered fossil, at thresholds much higher than what was considered until now.