利用钻孔温度梯度重建过去气候变化进展

地球表面的温度信号向地下传播并影响地下温度剖面,这种温度剖面可从钻孔中测量,通过分析可重建过去表面温度变化.虽然认识到表面温度变化对地下温度和热流的影响已有很长时间,但仅在20世纪80年代以后钻孔温度剖面才被广泛应用于气候变化研究.钻孔气候方法与其他重建过去气候的近似方法不同,因为它是基于温度剖面测量与过去气候,即地表温度(GST)、重构参数的直接物理联系之上的.钻孔温度气候研究方法已被证实可以重建过去地表温度趋势,并且最终可结合表面气温序列估计其预观测平均值(POMs).钻孔温度剖面并不是地表温度的代用指标,而是地球大陆表面能量平衡的直接测量.这种地下的信号通过热扩散衰减非常快,因而对从地下温度测量数据中提取过去气候变化信息的方法施加了一个物理限制.描述由钻孔中测量的温度—深度剖面来重建GST历史的基本特征及问题.     

Shallow geothermal regime in the Perth Metropolitan Area

Exploration of Perth's geothermal potential has been performed by the Western Australian Geothermal Centre of Excellence (WAGCoE). Detailed vertical temperature and gamma ray logging of 17 Western Australia Department of Water's (DoW) Artesian Monitoring (AM) wells was completed throughout the Perth Metropolitan Area (PMA). In addition, temperature logs from 53 DoW AM wells measured in the 1980s were digitised into LAS format. The logged data are available in the WAGCoE Data Catalogue.

Analysis of the gamma ray logs yielded the first estimates of radiogenic heat production in Perth Basin formations. Values by formation ranged between 0.24 and 1.065 μW m^?3. The temperature logs provide a picture of true formation temperatures within shallow sediments in the Perth Basin. A three-dimensional model of the temperature distribution was used to produce maps of temperature at depth and on the top of the Yarragadee aquifer.

The temperature data were interpreted with a one-dimensional conductive heat model. Significant differences between the model and the observations was indicative of heat moving via non-conductive mechanisms, such as advection or convection. Evidence of non-conductive or advective heat flow is demonstrated in most formations in the region, with significant effects in the aquifers. Average conductive geothermal gradients range from 13°C km^?1 to 39°C km^?1, with sandstone formations exhibiting average gradients of approximately 25°C km^?1, while insulating silt/shale formations show higher average gradients of over 30°C km^?1.

To produce preliminary heat flow estimates, temperature gradients were combined with thermal conductivities measured elsewhere. The geometric mean heat flow estimates range between 64 mW m^?2 to 91 mW m^?2, with the standard deviation of the arithmetic mean heat flow ranging between 15 and 23 mW m^?2.

The study characterises the shallow temperature regime in the Perth Metropolitan Area, which is of direct relevance towards developing commercial geothermal projects.     

西安城市地温与气温变化初步分析

地下浅层地温和近地表空气温度存在着必然的内在联系,地面温度变化的信息随着时间推移向下传播并叠加到稳态地温场上,因此通过对现今地温剖面的分析可以重建过去地面温度变化的历史。为了研究西安地区地下和地上的温度变化,本文在西安开展了钻孔温度测量,获得了16个钻孔的地温剖面,同时收集整理了西安气象站1951～2010年气温数据。对1951～2010年气温数据进行回归分析得到西安地区年平均气温、年平均最高气温和最低气温增温率分别为3.71 ℃/100a、2.03 ℃/100a和5.14 ℃/100a,均高于全国和全球平均水平,其中1986～2010年间平均气温增温更是显著,达到9.01 ℃/100a。从钻孔测温曲线中筛选出西安城郊6个传导型地温剖面进行分析,结果表明西安地区钻孔温度记录的地面温度变化趋势与气象台记录的气温变化趋势基本吻合。根据利用钻孔温度剖面下段回归分析得到的地表稳态温度和地温梯度以及25年间西安地区平均气温增温率推算得到钻孔理论地温剖面与实测地温数据总体上具有较好的一致性。对实测地温数据的进一步精确拟合分析显示,西安城郊6个选定的钻孔所在区域地面温度变暖分别起始于20年、24年、26年、28年、30年和30年前,对应的地表增温幅度分别为0.4 ℃、0.72 ℃、2.18 ℃、4.2 ℃、2.4 ℃和2.4 ℃。市区和周边郊区钻孔所在区域在增温幅度上存在明显的差异,市区增温强度明显高于郊区,而城郊结合部介于两者之间。     

Design of gas drainage modes based on gas emission rate in a gob: a simulation study

In the process of working face advance in longwall coal mining, a great deal of gas relieved by the strata adjacent to the mining coal seam and the residual coal in gob migrates to gob. If the gas drainage method in gob is unreasonable, gas will accumulate in the upper corner and overrun in the return air flow. In the paper, a CFD (computational fluid mechanics) model of gob based on the actual geological conditions and gas drainage mode of 1262 working face of Dingji Coal Mine, China, was established. The gas drainage modes that should be taken to effectively control gas accumulation in the upper corner and gas overrun in the return air flow at different gas emission rates were discussed. The simulation results show that when the gas emission rate in the working face is lower than 20 m³/min, buried pipe drainage can effectively control gas accumulation in the upper corner and gas overrun in the return air flow. When gas emission rate there is between 20 and 30 m³/min, the two problems can be solved through cross-measure borehole drainage combined with buried pipe drainage. When gas emission rate there is higher than 40 m³/min, they can be effectively controlled through a three-dimensional drainage mode including buried pipes, cross-measure boreholes, and surface wells. Arranging surface wells within the fractured zone near the return airway can increase the gas drainage rate, and the gas concentration can reach over 85%; the gas concentrations of buried pipe drainage and cross-measure borehole drainage are 15~20% and 70~80%, respectively.     

Performance and Sustainability of District-Scale Ground Coupled Heat Pump Systems

This study proposes a solution to the problem of maintaining the performance and sustainability of district-scale, cooling-dominated ground coupled heat pump (GCHP) systems. These systems tend to overheat because heat dissipates slowly in relation to the size of the borefields. To demonstrate this problem, a 2000-borehole field is considered at a district-scale GCHP system in the Upper Midwest, US. The borefield’s ground and fluid temperature responses to its design heating and cooling loads are simulated using computational fluid dynamics implemented by applying the finite volume method. The ground temperature is predicted by applying the thermal loads uniformly over the borefield and simulating heat dissipation to the surrounding geology through conduction coupled with advection due to groundwater flow. The results show that a significant energy imbalance will develop in the ground after the first few years of GCHP operation, even with high rates of groundwater flow. The model presented in this study predicts that the temperature at the center of the borefield will reach 18 °C after 5 years and approximately 50 °C after 20 years of operation in the absence of any mitigation strategies. The fluid temperature in the boreholes is then simulated using a single borehole model to estimate the heat pump coefficient of performance, which decreases as the modeled system heats up. To balance the energy inputs/outputs to the ground—thus maintaining the system’s performance—an operating scheme utilizing cold-water circulation during the winter is evaluated. Under the simulated conditions, this mitigation strategy carries the excess energy out of the borefield. Therefore, the proposed mitigation strategy may be a viable measure to sustaining the operating efficiency of cooling-dominated, district-scale borefields in climates with cold winters.     

Air-sea interaction over the tropical Indian Ocean during several contrasting monsoon seasons

Monthly mean anomaly fields of various parameters like sea surface temperature, air temperature, wind stress, effective radiation at the surface, heat gain over the ocean and the total heat loss between a good and bad monsoon composite and the evaporation rates over the Arabian Sea and southern hemisphere have been studied over the tropical Indian Ocean. The mean rates of evaporation on a seasonal scale over the Arabian Sea during a good and bad monsoon composites were equal (about 2·48 × 10¹⁰ tons/day). The evaporation rates over the southern hemisphere were greater during all the months. The mean evaporation rates over the southern hemisphere on a seasonal scale for the good and bad monsoon composites were 4·4 × 10¹⁰ and 4·6 × 10¹⁰ tons/day respectively. The maximum evaporation rates over the southern hemisphere were observed in August. The anomalies of wind stress, effective radiation at the surface and the heat gain over the ocean also exhibit large variations in August, as compared to other monsoon months.     

Effect of thermal-hydrogeological and borehole heat exchanger properties on performance and impact of vertical closed-loop geothermal heat pump systems

Ground-source geothermal systems are drawing increasing attention and popularity due to their efficiency, sustainability and being implementable worldwide. Consequently, design software and regulatory guidelines have been developed. Interaction with the subsurface significantly affects the thermal performance, sustainability, and impacts of such systems. Reviewing the related guidelines and the design software, room for improvement is evident, especially in regards to interaction with groundwater movement. In order to accurately evaluate the thermal effect of system and hydrogeological properties on a borehole heat exchanger, a fully discretized finite-element model is used. Sensitivity of the loop outlet temperatures and heat exchange rates to hydrogeological, system and meteorological factors (i.e. groundwater flux, thermal conductivity and volumetric heat capacity of solids, porosity, thermal dispersivity, grout thermal conductivity, background and inlet temperatures) are analyzed over 6-month and 25-year operation periods. Furthermore, thermal recovery during 25  years after system decommissioning has been modeled. The thermal plume development, transport and dissipation are also assessed. This study shows the importance of subsurface thermal conductivity, groundwater flow (flux > 10^?7 m/s), and background and inlet temperature on system performance and impact. It also shows the importance of groundwater flow (flux > 10^?8 m/s) on thermal recovery of the ground over other factors.     

Reconstructions of long-term ground surface heat flux changes from deep-borehole temperature data

Based on analysis of geothermal data from the Ural superdeep borehole (SG-4) and Onega parametric borehole, the first reconstructions of ground surface heat flux changes for the last 40 kyr have been made. The increase in heat flux during the Pleistocene-Holocene warming (20-10 ka) proceeded ~ 2 kyr earlier than the growth in surface temperature; reaching the maximum value of 0.08-0.13 W/m² at ~ 13 ka, the heat flux was reduced. The coordinated changes in heat flux and average annual insolation at 60° N at 5-24 ka indicate that the orbital factors were the main cause of climatic changes in this period. The correlations between the changes in heat flux and CO₂ content in the Antarctic ice cores and the temperature changes are analyzed.© 2014, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.     

咸阳地热田钻孔温度测量及水动力系统

地热田温度场分析, 不仅为地热田类型划分和热源机理研究提供科学根据, 而且可以为确定地热田有利开采区域和深度提供直接依据。本文报道了咸阳地热田13口钻孔的系统(准)稳态测温数据, 对研究区温度的垂向分布特征做了初步分析, 并据此划分了地热田水动力系统。结果表明, 咸阳地热田属于以传导为主的沉积盆地型地热田, 地温梯度为26.2~40.1 ℃/km, 平均为32.4 ℃/km。然而, 与典型的传导型地热田相比, 咸阳地热田的地温场特征又存在特殊性, 表现为钻孔温度-深度曲线分段性明显: 浅部受地表水流动对温度场的影响, 地温曲线呈现出锯齿形波动; 钻孔中上部受地表水和深部水热活动影响较小, 温度曲线为传导性地热特征; 井孔中下部测温曲线明显"下凹", 揭示了地下水沿渭河断裂侧向补给的同时使地层温度降低; 井孔下部温度随深度异常增大, 表明存在异常压力流体封存箱。测温资料揭示了咸阳地热田水动力系统在垂向上存在多层结构: 浅部为垂向重力驱动型, 中上部为正常压实型, 中下部为侧向重力驱动型, 下部为封闭型。基于咸阳地热田水动力系统的多层结构, 建议将各系统赋存的地热资源分别进行规划和开发。     

New heat flow data from the immediate vicinity of the Kola super-deep borehole: Vertical variation in heat flow confirmed and attributed to advection

We present new heat flow values and other geothermal data in the upper crystalline crust in the immediate vicinity of the 12.4-km deep Kola super-deep borehole, NW Russia. Our results show a systematic vertical increase in geothermal gradient and heat flow density as deep as we could measure (1.6 km). Our results confirm earlier results on vertical heat flow trends of in the uppermost part of the Kola super-deep hole, and imply that the thermal regime is not in steady-state conductive conditions. In an area of 3-km × 5-km measurements were performed in 1–2-km deep boreholes surrounding the Kola super-deep hole and on core samples from these holes. Temperature logs are available from 36 holes. Core data exists from 23 boreholes with a total length of 11.5 km at a vertical resolution of 10 m. We carried out a very detailed study on thermal conductivity with regard to anisotropy, inhomogeneity and temperature dependence. Tensor components of thermal conductivity were determined on 1375 core samples from 21 boreholes in 3400 measurements. Additionally, we measured specific heat capacity, heat generation rate, density, porosity, and permeability on selected subsets of core samples. Heat flow from 19 boreholes varies between 31 and 45 mW m⁻² with an average value of 38 mW m⁻². In most boreholes the vertical heat flow profiles show a considerable variation with depth. This is consistent with observations in the upper part of the Kola super-deep borehole. We conclude that this variation is not caused by technical operations but reflects a natural process. It is considered to be due to a combination of advective, structural and paleoclimatic effects. Preliminary 3-D numerical modeling of heat and flow in the study area provides an indication of relative contributions of each of these factors: advective heat transfer turns out to have a major influence on the vertical variation of heat flow, although transient changes in surface temperature may also cause a significant variation. Heterogeneity of the rocks in the study area is less important.     

地表暖化影响下温度示踪地下水流速方法

为构建温度示踪方法测算地下水流速技术体系,并应用于区域地下水资源评价,基于最小二乘法和垂向一维非稳定流水-热运移方程数值解法,提出地表暖化情形下地下水流速计算方法,并对雷州半岛东北部地下水流速进行测算。结果表明:研究区域地下水补给速度为0.796m/a,入渗以西北部降水和运河渗漏为主;地下水排泄速度为0.269m/a,排泄入海主要发生在东海岛、南三岛和硵州岛附近。温度示踪解析区域地下水流动情况与地下水位分布情况基本一致,观测和计算地温数据具有较强相关性(R^2>0.50)和较低均方根误差(均值0.748),表明提出方法率定得到的地下水流速具有较强的可靠性。参数敏感性分析结果表明,地质体热扩散率和地表温度均对地温计算结果产生较明显的影响,参数的准确率定对利用地温计算地下水流速十分重要。     

基于冰川钻孔温度的古气候重建研究进展北大核心CSCD

冰川内部温度与过去冰面温度变化密切相关,因此可以利用冰川钻孔温度对过去冰面温度变化过程进行重建。耦合的热传导-冰流物理模型与相关反演算法,是基于冰川钻孔温度进行古气候重建研究的理论基础和关键。论文收集了过去三十多年基于冰川钻孔温度进行古气候重建的研究文献,从冰川钻孔温度对气候变化的响应和古气候重建等方面进行了概述,并简要讨论了不同反演算法的优劣性和适用条件。尽管很多因素(如太阳辐射、融水等)都会对冰川钻孔温度造成影响,但两极或高纬地区的冷冰川钻孔温度能较好地反映气候变化历史。目前已通过这些不同地区的冰川钻孔温度,重建了末次冰期冰盛期以来不同时间尺度的气候变化历史,同时可与对应的冰芯记录相互印证。此外,通过冰川钻孔温度可以研究冰川与气温的耦合作用,并进一步预测冰川对未来气候变化的响应。利用中纬度冷冰川钻孔温度开展古气候重建的研究较少,未来加深这一方面的研究将有助于揭示中纬度高海拔地区的气候变化状况。     

Post-drilling destabilization of temperature profile in borehole Yaxcopoil-1, Mexico

As part of the International Continental Scientific Drilling Program (ICDP), the 1.5-km-deep borehole Yaxcopoil-1, located in the Chixculub meteor impact structure in Mexico, has undergone further study after drilling operations ceased. Temperature logs were repeated ten times at intervals 0.3–0.8, 15, 24 and 34 months after borehole shut-in. The logs bear a distinct signature of transient heat transfer by groundwater flow manifested by a gradual distortion of the linear temperature profile when a cold wave of 0.8–1.6°C amplitude was detected propagating downward from 145 to 312 m at a rate of 4–6 m/month. To understand the nature of this moving anomaly, a 20-day monitoring of the cold wave was carried out at a depth of 307 m that showed further cooling of 0.6°C during the first 16 days of the passage followed by temperature stabilisation. As an explanation of this unusual phenomenon, a theory is proposed, whereby the drilling mud has accumulated within the overlying and cooler highly porous and permeable karstic rocks during the drilling and migrates downward. The observed migration rate suggests a permeability higher than 10^?11 m². This indicates a high vulnerability to contamination of the only freshwater aquifer in the Yucatan region.     

Hydrochemistry and gas geochemistry of the northeastern Algerian geothermal waters

This study focuses on the water and gas chemistry of the northeastern Algerian thermal waters. The helium gas was used to detect the origin of the geothermal fluid. In the Guelma Basin, the heat flow map shows an anomaly of 120 ± 20 mW/m² linked to the highly conductive Triassic extrusion. The chemical database reveals the existence of three water types, Ca-SO₄/Na-Cl, which are related to evaporites and rich in halite and gypsum minerals. The third type is Ca (Na)-HCO₃, which mostly characterizes the carbonated Tellian sector. The origin of thermal waters using a gas-mixing model indicates a meteoric origin, except for the El Biban hot spring (W10), which shows a He/Ar ratio of 0.213, thus suggesting the presence of batholith. The helium distribution map indicates a lower ³He/⁴He ratio between 0 Ra and 0.04 Ra in the W10 and W15 samples, which is compatible with the crustal ratio. Reservoir temperatures estimated by silica geothermometers give temperatures less than 133 °C. The geothermal conceptual model suggests that a geothermal system was developed by the deep penetration of infiltrated cold waters to a depth of 2.5 km and then heated by a conductive heat source (batholith for El Biban case). The thermal waters rise up to the surface through the deep-seated fractures. During their ascension, they are mixed with shallow cold groundwater, which increase the Mg content and cause the immature classification of the water samples.     

2-D Crustal thermal structure along Thuadara-Sindad DSS profile across Narmada-Son lineament,central India

Central India is traversed by a WSW-ENE trending Narmada-Son lineament (NSL) which is characterized by the presence of numerous hot springs, feeder dykes for Deccan Traps and seismicity all along its length. It is divided in two parts by the Barwani-Sukta Fault (BSF). To the west of this fault a graben exists, whereas to the east the basement is uplifted between Narmada North Fault (NNF) and Narmada South Fault (NSF). The present work deals with the 2-D thermal modeling to delineate the crustal thermal structure of the western part of NSL region along the Thuadara-Sindad Deep Seismic Sounding (DSS) profile which runs almost in the N-S direction across the NSL. Numerical results of the model reveal that the conductive surface heat flow value in the region under consideration varies between 45 and 47mW/m². Out of which 23mW/m² is the contribution from the mantle heat flow and the remaining from within the crust. The Curie depth is found to vary between 46 and 47 km and is in close agreement with the earlier reported Curie depth estimated from the analysis of MAGSAT data. The Moho temperature varies between 470 and 500°C. This study suggests that this western part of central Indian region is characterized by low mantle heat flow which in turn makes the lower crust brittle and amenable to the occurrence of deep focused earthquakes such as Satpura (1938) earthquake.     

Shallow groundwater temperature in the Turin area (NW Italy): vertical distribution and anthropogenic effects

This study investigated the thermal regime of shallow groundwater in the Turin area (NW Italy), where the large energy demand has motivated a new interest for renewable sources, such as the use of ground-source heat pumps for domestic heating and cooling. The vertical variability of the groundwater temperature between the ground surface and 10–20 m was detected: deeper temperatures were higher than shallow temperatures in spring, while a decrease with depth occurred in autumn. These variations are connected with the heating and cooling cycles of the ground surface due to the seasonal temperature oscillation. Variations below the seasonal oscillation are likely to be connected with the presence of advective heat transport due to the groundwater flow, according to the hydraulic features of a shallow aquifer. Temperature values mostly ranged between 12 and 14 °C in rural areas, while the values were between 14 and 16 °C below the Turin city. This groundwater warming is attributed to a widespread urban heat island phenomenon linked to warmer land surface temperatures in Turin city. Sparse warm outliers are connected with point heat sources and site-specific conditions of land and subsurface use, which may cause the aquifer temperature to rise. A relatively stable temperature below the seasonal fluctuation zone combined with high productivity and legislated limits for deeper groundwater use represent favourable conditions for a large-scale diffusion of groundwater heat pumps within the shallow aquifer. Moreover, this heat surplus should be regarded as a resource for future geothermal installations.     

Emission reduction technology and application research of surface borehole methane drainage in coal mining-influenced region

Windblown methane is an important gas resulting in atmospheric greenhouse effect. Therefore, reduction in windblown methane is one of the important measures to mitigate atmospheric greenhouse effect. In China, weak coal seam of low permeability is common in coal mines, so it is beset with difficulties to decrease the methane emission rate by means of gas drainage from the virgin coal seam, further to decrease the windblown mine gas. Utilizing the pressure relief and permeability and fluidity improvement effect in coal mining an approach to release methane emission through surface borehole was established, for example establishing a comprehensive deformation fracture model of surface borehole in extraction area based on quantitative rule of overlying rock movement in pit and forming a technology to select the surface borehole arrangement site in extraction area on the basis of deformation of bore frame structure and distribution characteristics of extraction flow field. And optimization technology of shape and structure of surface borehole in extraction area on the basis of ultimate stress analysis of surface borehole casing was given. The technology overcomes effectively the problem that surface borehole casing is vulnerable to premature fracture due to impact of strata movement on the surface borehole, and further increases the drainage result of the surface borehole. The technology has been test in China Shanxi Jincheng Sihe Coal Mine, achieving good results, including 12,000 Nm³/d pure methane drainage rate from single borehole, 85% methane concentration and 1.1 million Nm³ accumulative methane drainage, which demonstrate practicability and advanced performance of the technology.     

冻土温度状况研究方法和应用分析

分析讨论了冻土温度状况研究中相关问题,包括构成多年冻土层的岩性、含水量、结构和构造,决定多年冻土温度状况动态变化的地面温度与气温间的关系,地中热流,研究区域的确定以及取决于地层的岩性、含水量、结构和构造、容重的热量在地层内传播过程的热物理参数.在分析物理学、地学和气候学等学科研究结果的基础上,笔者认为:1)在研究冻土温度状况问题中,研究区域应根据所研究问题的时间尺度确定,由于多年冻土层内不同深度上的温度和热流(或温度梯度)随时间的不同影响深度也不同,研究数十年时间尺度的多年冻土温度状况问题,一般应取多年冻土下限处的地中热流(或温度梯度)作为问题的下边界条件;2)以气温积温(或气温)与地面温度积温(或地面温度)比值所定义的N系数不仅存在年变化、季节变化和日变化,并在求解时必须已知地面冻结(或融化)的持续时间,而在目前对于不同地面条件缺乏定量描述气温与地面温度间关系的实验基础.因此,在缺乏比较严格的地面条件定量描述的情况下,应用气温与地面温度之差描述二者间的关系可能更为简单;3)在青藏高原地区,由于不同区域地形、地面条件、地层岩性以及地中热流等存在着很大差异,因而,不同区域多年冻土的热状况也不同.所以,不能简单地以气温等值线进行多年冻土制图,更不能以此年冻土变化预报的基础.     

Effect of land surface processes on the Tibetan Plateau’s past and its predicted response to global warming: an analytical investigation based on simulation results from the CMIP5 model

Complex interactions between the land surface and atmosphere and the exchange of water and energy have a significant impact on climate. The Tibetan Plateau is the highest plateau in the world and is known as “Earth’s third pole”. Because of its unique natural geographical and climatic characteristics, it directly affects China’s climate, as well as the world’s climate, through its thermal and dynamic roles. In this study, the BCCCSM1.1 model for the simulation results of CMIP5 is used to analyze the variation of the land surface processes of the Tibetan Plateau and the possible linkages with temperature change. The analysis showed that, from 1850 to 2005, as temperature increases, the model shows surface downward short-wave radiation, upward short-wave radiation, and net radiation to decrease, and long-wave radiation to increase. Meanwhile, latent heat flux increases, whereas sensible heat flux decreases. Except for sensible heat flux, the correlation coefficients of land surface fluxes with surface air temperature are all significant at the 99 % significance level. The model results indicate rising temperature to cause the ablation of ice (or snow) cover and increasing leaf area index, with reduced snowfall, together with a series of other changes, resulting in increasing upward and downward long-wave radiation and changes in soil moisture, evaporation, latent heat flux, and water vapor in the air. However, rising temperature also reduces the difference between the surface and air temperature and the surface albedo, which lead to further reductions of downward and upward short-wave radiation. The surface air temperature in winter increases by 0.93 °C/100 years, whereas the change is at a minimum (0.66 °C/100 years) during the summer. Downward short-wave and net radiation demonstrate the largest decline in the summer, whereas upward short-wave radiation demonstrates its largest decline during the spring. Downward short-wave radiation is predominantly affected by air humidity, followed by the impact of total cloud fraction. The average downward short-wave and net radiation attain their maxima in May, whereas for upward short-wave radiation the maximum is in March. The model predicts surface temperature to increase under all the different representative concentration pathway (RCP) scenarios, with the rise under RCP8.5 reaching 5.1 °C/100 years. Long-wave radiation increases under the different emission scenarios, while downward short-wave radiation increases under the low- and medium-emission concentration pathways, but decreases under RCP8.5. Upward short-wave radiation reduces under the various emission scenarios, and the marginal growth decreases as the emission concentration increases.     

辽宁省地温场结构及变化特征

以辽宁省为例,采用统计分析方法,根据辽宁省61个气象站1951-2013年0~320 cm地温资料,分析了季节性冻土区地温场结构和变化特征。结果表明：地温最冷月出现时间随着深度增加而推后,辽宁各地浅层地温最冷月基本均为1月,深层地温最冷月为1-5月,深度越深温度越高。地温最热月出现时间也随深度增加而推后,浅层地温最热月为7、8月,深层地温最热月为8-10月,深度越深温度越低。越深层地温受地表影响越小,320 cm深度与地表的月平均最大温差达到19℃左右,40 cm深度与地表的月平均最大温差仅在8℃左右。随着深度增加,地温的季节变化减小,沈阳320 cm深度地温年内温差不足8℃。5~80 cm深度3-8月为储能期,160 cm深度5-9月为储能期,320 cm深度6-10月为储能期。越接近地表,地温日变化越显著,40 cm以下深度基本可以忽略日变化。沈阳地温升高程度大于气温,以向大气输送热量为主。地表最冷月变暖率明显大于最热月,但随着土层加深各土层最冷月、最热月变暖的程度无明显规律。深层地温的年际变化有时会受到更深层热源的非气候扰动。地温变化对气候、冻土区域工程等的影响不容忽视。