Implications of Warm Rain in Shallow Cumulus and Congestus Clouds for Large-Scale Circulations

Space-borne observations reveal that 20–40% of marine convective clouds below the freezing level produce rain. In this paper we speculate what the prevalence of warm rain might imply for convection and large-scale circulations over tropical oceans. We present results using a two-column radiative–convective model of hydrostatic, nonlinear flow on a non-rotating sphere, with parameterized convection and radiation, and review ongoing efforts in high-resolution modeling and observations of warm rain. The model experiments investigate the response of convection and circulation to sea surface temperature (SST) gradients between the columns and to changes in a parameter that controls the conversion of cloud condensate to rain. Convection over the cold ocean collapses to a shallow mode with tops near 850 hPa, but a congestus mode with tops near 600 hPa can develop at small SST differences when warm rain formation is more efficient. Here, interactive radiation and the response of the circulation are crucial: along with congestus a deeper moist layer develops, which leads to less low-level radiative cooling, a smaller buoyancy gradient between the columns, and therefore a weaker circulation and less subsidence over the cold ocean. The congestus mode is accompanied with more surface precipitation in the subsiding column and less surface precipitation in the deep convecting column. For the shallow mode over colder oceans, circulations also weaken with more efficient warm rain formation, but only marginally. Here, more warm rain reduces convective tops and the boundary layer depth—similar to Large-Eddy Simulation (LES) studies—which reduces the integrated buoyancy gradient. Elucidating the impact of warm rain can benefit from large-domain high-resolution simulations and observations. Parameterizations of warm rain may be constrained through collocated cloud and rain profiling from ground, and concurrent changes in convection and rain in subsiding and convecting branches of circulations may be revealed from a collocation of space-borne sensors, including the Global Precipitation Measurement (GPM) and upcoming Aeolus missions.     

天祝盆地边缘断层的全新世活动及盆地的演化与形成

根据作者１／５０，０００活断层地质填图的资料，讨论了天祝盆地内断层的全新世活动及盆地的形成与演化历史。结果表明，天祝盆地内断层的全新世活动强烈，上窑洞沟深槽揭示３９８０±５０ａＢ．Ｐ．曾发生过一次古地震事件，天祝盆地是一个典型的拉分盆地，其形成及演化与断裂活动密切相关．     

Regional differentiation of ecological conservation and its zonal suitability at the county level in China

China’s investments, financial incentives and deductions in terms of ecological conservation are based at the county level. Therefore, the monitoring and assessment of the effects of ecological conservation at the county level is important to provide a scientific basis for the assessment of the ecological and environmental quality at the county scale. This paper quantitatively estimated the dynamics of high-quality ecosystems and vegetation coverage over the past 15 years, and their relationships with the number of ecological conservation programs at the county level were analyzed. Then, the effects of ecological conservation measures on ecological changes at the county level and their regional suitability were assessed and discussed. The results showed that counties with a percentage of high-quality ecosystems greater than 50% were primarily distributed in northeastern China, southern subtropical China and the southeastern Qinghai-Tibet Plateau, and those with a percentage lower than 20% were mostly distributed in northwestern China, the southwestern karst region and the North China Plain. In recent decades, ecological conservation has focused on ecologically fragile regions; more than five ecological conservation programs have been implemented in most counties of the Three River Source Region in Qinghai Province, southeastern Tibet, western Sichuan, the Qilian Mountains, southern Xinjiang and other western regions, while only one or zero have been implemented in the eastern coastal area of China. Over the past 15 years, the proportional area of high-quality ecosystems has increased in approximately 53% of counties. The vegetation coverage of counties in the Loess Plateau, Huang-Huai-Hai Plain, Beijing-Tianjin-Hebei (Jing-Jin-Ji), Sichuan-Guizhou-Chongqing, and Guangdong-Guangxi provincial-level areas has increased significantly. However, it decreased in northern Xinjiang, central Tibet, central and eastern Inner Mongolia, the Yangtze River Delta and other regions. The relationships between the numbers of ecological conservation programs and the indicators of ecosystem restoration response, such as high-quality ecosystem and vegetation coverage, do not show positive correlations. These results suggest that ecological conservation programs should be planned and implemented according to the distribution patterns of high-quality ecosystems and that restoration measures such as afforestation should follow natural principles and regional differentiation under the background of climate change.     

渤海湾盆地黄骅坳陷孔南地区古近系孔店组二段物源分析*

根据重力异常资料、地震资料,综合运用重矿物法、碎屑岩类分析法并结合砂体展布特征,基本明确了黄骅坳陷孔南地区孔店组二段的物源区位置及来源方向。区域布格重力异常场从宏观上勾绘出了孔南地区地势的起伏状况,对物源分析具有重要参考意义。在研究区湖盆周缘都发育砂体,在各物源口的砂体展布规律在平面上表现为呈扇形展布的特征,宏观上指示了物源的涉及范围。盆外下切沟槽能大致确定研究区周缘各物源口位置,前积反射结构也能指示出存在物源供给的地区。重矿物以锆石、电气石、金红石、石榴石、磁铁矿为主,不同的物源区具有不同的重矿组合特征,其变化规律指示了碎屑物质的搬运方向和搬运途径。碎屑岩组分以长石为主,其次为石英,岩屑含量较低,主要为岩浆岩岩屑,岩屑类型指示了物源区母岩类型主要为岩浆岩。该区孔店组二段沉积时期在东南、西南、西北、东北4个方向上都存在物源,进一步可识别出乌马营、叶三拔、舍女寺等10个子物源,它们共同控制了孔南地区孔店组二段沉积时期砂体的形成和分布,形成多物源环湖盆分布的特征。     

Formation blockage risk analysis of geothermal water reinjection:Rock property analysis,pumping and reinjection tests,and long-term reinjection prediction

The blockage induced by particle migration and deposition is one of the main reasons for the decrease of reinjection capacity in the porous geothermal reservoir with a low and medium temperature.In this paper,a new drilled geothermal well in Xining basin China is taken as an example to investigate the formation blockage risk due to the movable clay and sand particles in pores.The physical properties of the reservoir rocks were analyzed,a series of pumping and reinjection tests were conducted,and the longterm reinjection performance of the well was predicted by numerical simulation based on the test fitting.The results show that the geothermal reservoir rocks are argillaceous and weakly cemented sandstones with a content of movable clay and sand particles up to 0.18–23.42 wt.%.The well presented a high productivity of 935–2186 m3?d-1 at a pressure difference of 0.7–1.62 MPa in the pumping tests associated with a large amount of clay and sand particles produced out,while in the reinjection test,only a low injectivity of 240–480 m3?d-1 was observed at an injection pressure of 0.2–0.6 MPa with the clay and sand particles near the wellbore move into deep.According to the prediction,under conditions of a blockage risk,the injectivity of the well will start to decline after 100 days of injection,and in the third year,it will decrease by 59.00%–77.09%.The influence of invasion of pretreated suspended particles and scale particles can be neglected.Under conditions of a high blockage risk,the injectivity of the well will decrease significantly in the first 20–30 days,with a decline of 75.39%–78.96%.Generally,the higher the injection pressure or rate,the greater the decrease in injectivity of the well caused by particle blockage.Pump lifting is an effective measure to remove the well blockage which can be used regularly.     

Strength Behavior of Shanghai Clayey Soil Reinforced with Wheat Straw Fibers

It is generally recognized that the low strength and high compressibility are the characteristics of soft soil. In addition to other techniques, reinforcement can also be used in increasing the strength and decreasing the deformation of this kind of soil. The results of an investigation into the effects of a natural fiber on the consolidation and shear strength behavior of Shanghai clayey soil reinforced with wheat straw fibers are presented in this paper. A series of one dimensional consolidation and triaxial tests were conducted on samples of unreinforced and reinforced Shanghai clayey soil with different percentages of randomly distributed wheat straw fibers. The results show that the preconsolidation pressure decreases and the coefficient of swelling and compression generally increase with increasing the fiber content until a optimum content value. Furthermore, the addition of wheat straw fiber leads to a significant increase in shear strength and friction angle of the natural soil and there is an optimum wheat fiber content that makes this increase maximal.     

Evaluating Tidal Wetland Restoration Performance Using National Estuarine Research Reserve System Reference Sites and the Restoration Performance Index (RPI)

Evaluations of tidal wetland restoration efforts suffer from a lack of appropriate reference sites and standardized methods among projects. To help address these issues, the National Estuarine Research Reserve System (NERRS) and the NOAA Restoration Center engaged in a partnership to monitor ecological responses and evaluate 17 tidal wetland restoration projects associated with five reserves. The goals of this study were to (1) determine the level of restoration achieved at each project using the restoration performance index (RPI), which compares change in parameters over time between reference and restoration sites, (2) compare hydrologic and excavation restoration projects using the RPI, (3) identify key indicator parameters for assessing restoration effectiveness, and (4) evaluate the value of the NERRS as reference sites for local restoration projects. We found that the RPI, modified for this study, was an effective tool for evaluating relative differences in restoration performance; most projects achieved an intermediate level of restoration from 2008 to 2010, and two sites became very similar to their paired reference sites, indicating that the restoration efforts were highly effective. There were no differences in RPI scores between hydrologic and excavation restoration project types. Two abiotic parameters (marsh platform elevation and groundwater level) were significantly correlated with vegetation community structure and thus can potentially influence restoration performance. Our results highlight the value of the NERRS as reference sites for assessing tidal wetland restoration projects and provide improved guidance for scientists and restoration practitioners by highlighting the RPI as a trajectory analysis tool and identifying key monitoring parameters.     

Groundwater resources in the Jabal Al Hass region,northwest Syria: an assessment of past use and future potential

In many cases, the development of groundwater resources to boost agricultural production in dry areas has led to a continuous decline in groundwater levels; this has called into question the sustainability of such exploitation. In developing countries, limited budgets and scarce hydrological data often do not allow groundwater resources to be assessed through groundwater modeling. A case study is presented of a low-cost water-balance approach to groundwater resource assessments in a 1,550 km² semi-arid region in northwestern Syria. The past development of irrigated agriculture and its effect on the groundwater system were studied by analysis of Landsat images and long-term groundwater level changes, respectively. All components of the groundwater balance were determined. Groundwater recharge was estimated using the chloride mass balance method. Over the past three decades, groundwater levels have declined, on average, 23 m, coinciding with a two-fold increase in the groundwater-irrigated area. Groundwater resources are currently depleted by a value that lies between 9.5×10⁶ and 118×10⁶ m³ year^?1, which is larger than can be compensated for by a future decrease in natural discharge or changes in boundary conditions. However, groundwater resources are likely to be sufficient to supply domestic and livestock needs in the area.     

任意各向异性介质三维有限元航空电磁响应模拟

在航空电磁探测方法应用中,地下探测环境复杂,地下介质物性参数存在各向异性特征。如果采用常规各向同性介质模型,在资料解释过程中会产生严重的偏差。本文基于矢量有限元法开展三维任意各向异性频率域航空电磁响应模拟计算研究。首先,将总场分解成一次场和二次场,对空气介质的均匀全空间进行一次场解析计算,同时利用矢量有限元法对二次电场的双旋度方程进行求解。为提高求解速度,采用共享内存直接求解器PARDISO对大规模稀疏矩阵并行计算,大大提高了三维模型的计算速度。之后开展了4种典型目标模型的三维各向异性介质模拟：围岩各向同性-目标体各向异性（绕z轴旋转）模型;围岩各向同性-目标体各向异性（绕x轴旋转）模型;围岩各向异性-目标体各向异性（绕z轴旋转）模型;围岩各向异性-目标体各向异性（绕x轴旋转）模型。对比分析了不同模型在不同旋转角度情况下,磁场实虚分量的变化特征,进而总结了各向异性参数对航空电磁响应的影响规律和识别方法。     

An evaluation of the genesis and suitability of groundwater for irrigation in the Volta Region,Ghana

Stable isotope data and concentrations of the major cations and anions of groundwater from the northern part of the Volta Region, Ghana, were used to determine the source of recharge and the suitability of groundwater in the area for irrigation. This study finds that the delta deuterium (δD) and delta Oxygen-18 (δ¹⁸O) data from the area fall along the global meteoric water line (GMWL). An equation of regression derived for the relationship between δD and δ¹⁸O bears very close semblance to the equation which describes the GMWL. On the basis of this, groundwater in the study area is probably meteoric and fresh. The apparently low salinities and sodicities of the groundwater seem to support this interpretation. The suitability of groundwater for domestic and irrigation purposes is related to its source, which determines its constitution. A plot of the sodium adsorption ratio (SAR) and electrical conductivity (EC) data on a semilog axis, suggests that groundwater serves good irrigation quality in the area. Sixty percent (60%), 20% and 20% of the 67 data points used in this study fall within the medium salinity–low sodicity (C2–S1), low salinity–low sodicity (C1–S1) and high salinity–low sodicity (C3–S1) fields, which ascribe good irrigation quality to groundwater from this area. Salinities range from 28.1 to 1,956 μS/cm, whilst SAR values fall within the range 0–3. Extremely low sodicity waters of this kind, with salinities lower than 600 μS/cm, have the tendency to affect the dispersive properties of irrigation soils when used for irrigation. About 50% of the groundwater in the study area fall within this category and need prior treatment before usage.