不同土壤热通量测算方法的比较及其对地表能量平衡闭合影响的研究

土壤热通量是地表能量平衡的重要分量,对其测算方法的研究对理解能量平衡过程具有十分重要的意义.利用2010年馆陶站土壤热通量等相关观测数据对多种测算土壤热通量的方法:实测土壤热通量和热储存量的结合方法(PlateCal)、热传导方程校正法(TDEC)、谐波分析法(HM)、平均土壤热电偶法(TCAV)、耦合热传导—对流法(ITCC)获取的地表土壤热通量进行了对比分析,并且采用最优方法计算馆陶站2008-2010年的地表土壤热通量,分析了该站土壤热通量日、季节变化特征.主要结论如下:①PlateCal和TDEC法分别为获取土壤热通量的最优观测与计算方法,而HM,TCAV和ITCC法计算结果均不理想;②PlateCal与TDEC法对地表土壤温度均不敏感,而HM法对地表土壤温度则比较敏感,各种地表土壤热通量的观测与计算方法均对土壤湿度敏感;③馆陶站冬小麦、玉米覆盖地表及地表裸露时期的地表土壤热通量均呈现典型的日、季节变化特征,与净辐射变化趋势一致;④考虑热储存后,可将馆陶站2010年各月地表能量闭合率提高4％～11％,对2008-2010年的年能量平衡闭合率提高3％～5％.     

大尺度水热通量观测系统的研制

基于闪烁理论、孔径平均效应及莫宁-奥布霍夫相似理论(MOST),成功研制了大尺度水热通量观测系统样机YZ01,该系统主要由发射器、接收器、云台、瞄准器、气象传感器、数据采集器、数据处理软件、远程无线数据传输模块、太阳能供电系统等部分组成.该系统发射器平均功耗3W,接收器功耗1.8 W,比德国的BLS450和荷兰的LAS都更省电;发射器光源功率为100 mW,比荷兰LAS的80 mW更强,在同样条件下,YZ01接收器接收到的闪烁光解调信号比荷兰LAS强14%左右,说明在相同的安装距离下,YZ01比荷兰LAS更适于在能见度低的条件下使用,或者说在同样的环境条件下,YZ01比荷兰LAS可以测量更远的距离.YZ01在北京密云站与荷兰Kipp＆Zonen公司的LAS、美国Campbell公司的涡度相关测定系统进行了短期的应用对比试验,结果为:空气折射指数的结构参数Cn2、感热通量H、潜热通量LE的日变化趋势都非常一致;YZ01与LAS之间Cn2的线性拟合系数为0.98,相关系数为0.7;H的线性拟合系数为0.90,相关系数为0.93;YZ01通过余项法算出的LE与涡度相关直接测得的LE的线性拟合系数为1.07,相关系数为0.78.YZ01在青海阿柔站与德国Scintec公司的BLS450进行对比结果为:空气折射指数的结构参数Cn2、感热通量H、潜热通量LE的日变化变化趋势也都非常一致,YZ01与BLS450之间Cn2的线性拟合系数为1.25,相关系数为0.93;H的线性拟合系数为1.17,相关系数为0.99;YZ01通过余项法算出的LE与涡度相关测定系统测得的LE的线性拟合系数为1.03,相关系数为0.84.表明该研究所研制的大尺度水热通量观测系统不仅可以达到国外同类仪器同样的应用水平,而且比国外同类产品更省电、比荷兰LAS更适应在低能见度条件下使用.     

草原生长期地表辐射和能量通量月平均日变化特征

利用2008年5—9月锡林浩特国家气候观象台辐射和通量观测资料,分析了锡林浩特典型草原生长期各辐射分能量和同期能量通量的月平均日变化以及地表能量闭合度.结果表明:草原生长期总辐射月平均日最大值出现在7月,平均日最大辐射强度达到753.14W·m-2,最小值出现在5月,为697.27W·m-2.受地表反照率和太阳总辐射的影响,生长期反射辐射最大值出现在5月份,平均日积分值为4.92MJ·m-2;9月份最小,平均日积分值为3.76MJ·m-2.生长期获得的辐射能量为1385.67MJ·m-2,平均净辐射(Rn)强度为104.52W·m-2;感热通量(H)共支出640.39MJ·m-2,日平均强度为53.40W·m-2;潜热通量(LH)共支出772.96M·m-2,日平均强度为55.10W·m-2.Rn和H+HL+G线性回归的结果显示,草原生长期日平均能量闭合率为90%,能量不闭合程度为10%.     

Reply to comments by R. Von Herzen, E.E. Davis, A.T. Fisher, C.A. Stein and H.N. Pollack on “Earth's heat flux revised and linked to chemistry”

The lengthy comment by Von Herzen et al. does not address the most important conclusions of the paper by Hofmeister and Criss [Hofmeister, A.M., Criss, R.E., 2005, Earth's heat flux revisited and linked to chemistry. Tectonophys. 395, 159–177.]. These are 1) that actual measurements better describe the Earth than do simplistic models with demonstrably unrealistic boundary conditions that diverge markedly from the data; and 2) that the models are unconstrained, resulting in a series of papers proposing values for the global flux that have become increasingly disparate from the growing data base over time (Fig. 3 in our paper). We disagree strongly with penultimate concluding statement of Von Herzen et al., “that it is preferable to base surface heat flow analysis not only on the extensive measurements but also on well understood processes that are known to bias the values and statistics of the measurements,” as our Fig. 3 demonstrates that no consistent magnitude has been assigned to the alleged advective flux, so that neither the processes nor the correction are “well understood”. We do not deny the existence of submarine hydrothermal systems, but we disagree strongly with the scales over which they are alleged to operate, and with the large Rayleigh and Nusselt numbers Von Herzen et al. assign to them.     

Determination of paleoheat-flux using multiple thermal indicator tomography

Multiple thermal indicator tomography is a non-linear inversion procedure which permits simultaneous determination of geological, chemical kinetic, and thermal parameters in the burial and thermal histories of sediments. The procedure is based on inverting measurements with depth in a well of multiple thermal indicators, each of which must have experienced the same thermal history. For two wells from diverse geological settings, tomography is used to assess the paleoheat-flux variations with time most consistent with all the thermal indicator data. Resolution and sensitivity of the results are also addressed. For the case history of well X in the North Sea, with both vitrinite reflectance and sterane isomer thermal indicators, a generally decreasing heat flux from past to present is obtained roughly halving every 50 Ma. The activation energy for the sterane isomer is also determined simultaneously to be 42±20 kJ/mole. For the second case history of the Irma Mclean well in the onshore Gulf of Mexico, data from four thermal indicators are available: vitrinite reflectance, sterane and hopane isomers, and sterane aromaticity. A general decrease in paleoheat-flux from amount 2.8 heat flux units (HFU) at 100 MaBP to 1.25 HFU at the present day is obtained, the activation energy for the sterane isomer is simultaneously determined to be around 50±20 kJ/mole, while the corresponding values are around 80±20 kJ/mole for the hopane isomer, and around 65±20 kJ/mole for sterane aromatization.     

西北地区大气水汽的区域分布特征及其变化

对西北地区大气水汽的区域分布及变化特征进行了分析.结果表明:受不同气候系统影响的西北地区可划分为西风带、高原区与东亚季风等3个气候影响区,水汽沿西北、西方与西南3条路径输送到西北地区;东亚季风区是西北大气可降水量和水汽通量的最丰富区,西风带区是次之,高原区最少.平均状况下,高原区的边坡、东亚季风区、天山及祁连山等西北地区降水最大和次大中心维持水汽的辐合状态.西风带区在1978年以前净水汽通量呈“亏损”状态,之后维持“盈余”;高原区净水汽通量一直为“亏损”状态;东亚季风区90年代以前净水汽通呈“盈余”状况,其后基本维持平衡,且数值远大于其它区.西风带区降水和大气水汽在变化过程中均有突变发生,时间分别为1990年和1985年,其它两区没有突变现象发生.     

An analysis of MONTBLEX data on heat and momentum flux at Jodhpur

Parameterization of sensible heat and momentum fluxes as inferred from an analysis of tower observations archived during MONTBLEX-90 at Jodhpur is proposed, both in terms of standard exchange coefficientsC _H andC _D respectively and also according to free convection scaling. Both coefficients increase rapidly at low winds (the latter more strongly) and with increasing instability. All the sensible heat flux data at Jodhpur (wind speed at 10 m Ū₁₀ < 8 ms⁻¹) also obey free convection scaling, with the flux proportional to the ‘4/3’ power of an appropriate temperature difference such as that between 1 and 30 m. Furthermore, for Ū₁₀ < 4 ms⁻¹ the momentum flux displays a linear dependence on wind speed.     

能量平衡融雪模型在乌鲁木齐河源区的应用

山区融雪是内陆河流域重要的径流补给来源,融雪径流模拟是干旱区水文预报的研究热点。针对山区积雪消融的不确定性过程,根据能量平衡原理,以乌鲁木齐河源区融雪性洪水多发期为研究时段(2010年3月14日~4月12日),结合MODIS积雪产品和气象观测数据,采用GIS空间分析平台,阐述了融雪过程中能量平衡各收支通量变化的计算过程,并分析了融雪水量空间分布特征。模拟计算结果表明:乌鲁木齐河源区显热通量和潜热通量的日空间变化波动相似,但方向相反;日融雪量数值波动不大,但日融雪量空间分布不均,日平均融雪水量约为8.6 kg/m~2;融雪产流模拟结果和同期出山口水文站监测结果相吻合,Nash-Sutcliffe系数(R~2)和径流体积差分析(D_v)分别为0.76和6.72%,满足精度要求。该研究结果对干旱区内陆河流域融雪型洪水预报具有参考意义。     

Pelagic processes and vertical flux of particles: an overview of a long-term comparative study in the Norwegian Sea and Greenland Sea

Pelagic processes and their relation to vertical flux have been studied in the Norwegian and Greenland Seas since 1986. Results of long-term sediment trap deployments and adjoining process studies are presented, and the underlying methodological and conceptional background is discussed. Recent extension of these investigations at the Barents Sea continental slope are also presented. With similar conditions of input irradiation and nutrient conditions, the Norwegian and Greenland Seas exhibit comparable mean annual rates of new and total production. Major differences can be found between these regions, however, in the hydrographic conditions constraining primary production and in the composition and seasonal development of the plankton. This is reflected in differences in the temporal patterns of vertical particle flux in relation to new production in the euphotic zone, the composition of particles exported and in different processes leading to their modification in the mid-water layers.In the Norwegian Sea heavy grazing pressure during early spring retards the accumulation of phytoplankton stocks and thus a mass sedimentation of diatoms that is often associated with spring blooms. This, in conjunction with the further seasonal development of zooplankton populations, serves to delay the annual peak in sedimentation to summer or autumn. Carbonate sedimentation in the Norwegian Sea, however, is significantly higher than in the Greenland Sea, where physical factors exert a greater control on phytoplankton development and the sedimentation of opal is of greater importance. In addition to these comparative long-term studies a case study has been carried out at the continental slope of the Barents Sea, where an emphasis was laid on the influence of resuspension and across-slope lateral transport with an analysis of suspended and sedimented material.     

The effect of typhoon induced rainfall on settling fluxes of particles and organic carbon in Yuanyang Lake, subtropical Taiwan

A sediment-trap monitoring program measured the fluxes of settling particles and organic carbon in Yuanyang Lake, northern Taiwan, from July 2004 to July 2006 and assessed their relations to the amounts of normal monthly and typhoon-event precipitation. The flux of settling particles varied from 0.7 mg cm^?2 month^?1 to 14.7 mg cm^?2 month^?1, and the monthly precipitation ranged from 56 mm to 1218 mm during the survey period. The contributions from typhoon-event precipitation to monthly rainfall amounts were generally larger than 70%. Higher inputs of both particulate and organic carbon into the lake were found during typhoon seasons. Of the annual settling particle loading of 14.9 tons year^?1 to the lake floor, 69% occurred during the typhoon months, and 62% of the annual organic carbon loading of 2.3 tons year^?1 happened during the typhoon months. These results show the importance of typhoon events on the fluxes of settling particles and organic carbon and their delivery to lakes.     

祁连山七一冰川消融期间的能量平衡特征

冰川表面的能量平衡可以描述冰雪消融与气候响应之间的物理机制,利用2006年6月9日至9月28日在祁连山七一冰川消融区中部自动气象站(AWS)的观测资料,对七一冰川表面的能量平衡进行了估算.结果显示:在冰川消融期,净辐射、湍流热通量和冰川消融耗热是能量平衡的主要组成部分,能量收入方面主要是净辐射和感热通量,分别约占总能量收入的82.4%和17.6%;而支出方面主要是冰雪消融耗热和潜热释放,分别约占总能量支出的87.2%和12.8%.2006年7月31日至8月6日进行了为期近7 d的冰面径流场观测,基于能量平衡原理,对冰川表面的消融进行了模拟,模拟的消融速率和实测的冰面消融数据吻合的较好.     

A methodology to determine thermal conductivity of soils from flux measurement

Determination of thermal properties of soils (viz., thermal resistivity, thermal conductivity, thermal diffusivity and heat capacity), which primarily influence heat migration through the soil mass, is essential in situations where geomaterials are relentlessly subjected to higher temperatures and temperature variations. These properties of the soil mainly depend upon its type, mineralogy, particle size and gradational characteristics, density and water content. In this context, earlier researchers have determined thermal conductivity of soils by employing a thermal probe (a line heat source), which works on the principle of transient method (TM) of heat conduction. However, this methodology cannot be employed for establishing the heat flow (read thermal regime) through the soil. Hence, development of an alternate technique, which facilitates quantification of temporal and spatial variation of the heat flux and temperature in the soil mass, becomes essential. With this in mind, a methodology to determine thermal conductivity of soils by employing the concept of thermal flux measurement (TFM) has been developed and its details are presented in this paper. Results obtained from the TM and TFM have also been critically evaluated for the sake of validation and generating more confidence in the proposed methodology.     

Temperature mapping,thermal diffusivity and subsoil heat flux at Kariavattom of Kerala

We have studied the soil and air temperature characteristics over a period of one year at Kariavattom of Kerala. Thermal diffusivity(k _s) of the soil has been calculated by range and lag methods and also from amplitudes and phase angles of first and second harmonics. The two methods lead to similar results. Diurnal soil heat flux and soil temperatures at different depths are modelled and found to be comparable with observations.     

Surface meteorological instrumentation for BOBMEX

Although India has a long experience in ship-borne experiments and oceanographic instrumentation, the atmospheric component has not received much attention in the past. In this paper, the basis of the atmospheric instrumentation system assembled for use on board ORV Sagar Kanya for the BOBMEX-Pilot experiment is described along with some representative results. Wherever possible, Woods Hole's IMET recommendations for meteorological sensors for applications in the marine environment have been followed to keep our measurements in par with international standards. The sensors were tested during the BOBMEX-Pilot experiment and all sensors worked well. Velocity, humidity and temperature data have been successfully collected using fast sensors. It is shown that the component due to the ship's pitching motion can be removed from the measured vertical velocity by making use of an accelerometer. This makes it possible to calculate the surface fluxes by direct methods.     

非对称天然沸石陶瓷膜的制备及其性能表征

利用天然沸石为主要原料,制备出具有过滤功能和重金属离子吸附功能的天然沸石非对称陶瓷膜。非对称膜中支撑体、中间层膜和顶层膜的平均孔径分别为6.6μm、0.6μm和0.1μm。非对称膜单位压力降(1 MPa)下的氮气通量和水通量分别为:24.69×103m3/(m2h)和1.87×103m3/(m2h);对重金属离子(铅离子)吸附交换能力为7.13 mg/g。     

温度对青藏高原高寒灌丛CO2通量日变化的影响

应用涡度相关技术连续监测的CO₂通量及温度数据(2003年1月1日至2004年12月31日),分析了青藏高原高寒灌丛净生态系统CO₂交换(NEE)日变化与温度之间的关系.结果表明:1)在暖季夜间(21:00至次日06:00时)温度与NEE变化呈显著正相关关联,而白昼(07:00~20:00时)NEE变化与温度无显著关联;2)在冷季不论夜间还是白昼,NEE变化均与温度密切相关,温度是决定冷季高寒灌丛生态系统CO₂交换的主要因素.在全球气候变暖背景下,青藏高原气候变化呈现出冬季增温率明显高于春、夏季特征,未来气候变暖导致的增温效应可能会加速青藏高原高寒灌丛生态系统CO₂排放,使其作为碳汇的能力而减弱.     

西安南郊和陕北长武土壤CO2 释放量研究

本文根据NaOH溶液吸收CO2的方法,对西安南郊和陕北长武地区土壤CO2释放量进行了昼夜观测。观测结果表明,不同地区土壤CO2释放量存在差异,气候偏冷偏干地区土壤CO2 释放量较小,气候偏热偏湿地区土壤CO2释放量较大。陕北长武土壤CO2释放量变化再次证明,从当日早晨至次日早晨, CO2释放量具有由低变高再变低的规律; CO2释放量相对于大气温度的日变化具有滞后性,滞后时间为4～6小时;土壤CO2释放量白天较少,夜间较多; CO2释放量变化显示,在土层深厚的地区,土壤微生物夜间活动强度总体应比白天大。      

科奇喀尔冰川夏季表碛区热量平衡参数的估算分析

利用能量平衡原理、热传导理论和通量传输理论建立了一个热量平衡参数的估算模型,对西天山的科奇喀尔冰川夏季消融区中部表碛区的热量平衡参数进行估算与分析.结果表明:净辐射是表碛面热量收支的主要热源,吸收的热量主要以潜热和感热的形式向大气输送水汽和热量,剩余部分用于表碛增温耗热.与消融区上部的冰面和表碛面相比,在消融区中部表碛面热量收入中感热输送减小,同时向上的地热输送增加.热平衡支出项中,感热交换、蒸发耗热和地热通量的比例分别为39.1%、39.9%和21%,其中感热通量与蒸发耗热的比例比消融区上部有所提高,蒸发耗热的增加比较显著.在总的热量支出中,平均只有7.8%的热量可以用于表碛下部的增温和向深层传导.     

深海热液活动环境场参数及模型分析

深海热液活动是当今科学研究的热点,本文基于近年有关热液活动的各种模型,系统分析比较了热液柱的上升高度与热通量等参数变化规律,并对现有的热液羽状流模型和考虑洋壳特性的经验模型进行了分析。主要研究结果有:(1)热液柱上升高度与底部横向流和热源特性密切相关,单个热液喷口热通量和羽状热液柱中性浮力层模型热液热通量达109W/m2;(2)热液羽状流受多种因素影响,热液柱面积的轮廓,羽状热液柱各处的含盐量、潜在温度、速度可随深度改变发生变化;(3)考虑洋壳特性后,其浮力通量和热液柱最大的上升高度均有变化,上升高度可达1000多m,热通量达108W/m2。上述模型和参数可为进一步深入研究热液羽流运动机制和建立热液活动正演和反演模型提供参考。     

呼伦贝尔市2016年3月31日-4月2日暴雪过程天气学特征研究

利用常规观测资料及NCEP 1.0°×1.0°再分析资料,对2016年3月31日至4月2日发生于呼伦贝尔市的一次暴雪天气过程的环流形势、成因机制进行分析,以期总结出此次暴雪的特殊之处,为今后的暴雪天气预报提供可参考的经验。从天气学角度详细地分析此次暴雪过程的高低空影响系统的生消演变,特别对产生极端降水的水汽输送条件、水汽辐合情况、局地水汽聚集以及垂直运动情况进行详尽的分析。研究结果表明：此次暴雪天气过程是由短波扰动叠加低空锋区,导致斜压有效位能释放转变为扰动动能,并促使扰动发展加深为大型涡动而产生;水汽通量分布形态在一定程度上决定了水汽输送效果,“均匀狭长”的分布形态具有更高的水汽输送效率;涡度差动平流与温度平流表明动力因子与热力因子在本次过程中对垂直运动均有显著贡献,而水平散度作为直接反映质量汇集、流失的参量可以更为直观地反映垂直运动的强弱与分布;整层水汽通量散度积分作为与降水强度直接相关的物理量,对于降水量级的反映异常精准,配合中低空气流强度与方向,可对降水落区与时段进行精确判断。