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621.
随着地源热泵技术的推广应用,浅层地温能作为新型可再生资源得到了重视,对浅层地温能的资源评价业已展开。目前,从浅层地温能赋存地区的地质特点出发,分析其资源可开采量的研究尚不多见。重点介绍了浅层地温能可开采资源量的常规评价方法,并针对苏北平原区的地质特点,分析了在苏北平原区的具体地质特征下不同评价方法的适用性,得出了地下水式地源热泵可开采资源量的适宜评价方法为地下水量折算法;地埋管式地源热泵可开采资源量的适宜评价方法为换热量现场测试法;通过对本地区的工程案例分析,验证了上述2种方法在苏北平原区浅层地温能可开采资源量评价中能取得较高的精度。 相似文献
622.
Christoph Clauser 《Surveys in Geophysics》2009,30(3):163-191
The heat of the Earth derives from internal and external sources. A heat balance shows that most of the heat provided by external
sources is re-emitted by long-wavelength heat radiation and that the dominant internal sources are original heat and heat
generated by decay of unstable radioactive isotopes. Understanding of the thermal regime of the Earth requires appreciation
of properties and mechanisms for heat generation, storage, and transport. Both experimental and indirect methods are available
for inferring the corresponding rock properties. Heat conduction is the dominant transport process in the Earth’s crust, except
for settings where appreciable fluid flow provides a mechanism for heat advection. For most crustal and mantle rocks, heat
radiation becomes significant only at temperatures above 1200°C.
相似文献
Christoph ClauserEmail: |
623.
主要分析了1951~2004年夏季亚洲极涡强度和面积的长期变化趋势及其对东亚夏季环流,水汽输送和降水量的影响,发现1951~2004年,夏季亚洲极涡表现出了明显的强度减弱,面积缩小的变化趋势,并以面积缩小更为显著,这正对应于北极涛动(AO)指数在该时段的显著升高.在这种北半球中高纬大尺度环流变化的影响下,东亚夏季高空西风急流在近54年显著南移,冷空气活动的南侵程度明显增强,从而造成低空偏北风显著增强而偏南风减弱.与此相应,近54年整个中国区域内低空纬向风速呈明显的减小趋势.总的来看,东亚夏季风环流发生了明显减弱.同时,流经中国的中纬度西风水汽输送在近54年也表现出一致减弱的趋势,而南风水汽输送大致以110°E为界,以东的夏季风区呈显著的减弱趋势而以西则有明显的增加趋势.这种水汽输送的变化影响了中国不同区域内水汽输送通量散度的改变,进而使得夏季降水量发生变化.分析表明,夏季亚洲极涡的面积和强度与东北、华北和西北东部的水汽输送通量散度和夏季降水呈正相关,而与长江中下游、华南、西南、青藏高原和西北西部呈显著负相关,夏季亚洲极涡在近几十年的面积缩小和强度减弱是中国夏季降水长期变化的一个可能原因. 相似文献
624.
利用1962~2006年NCEP/NCAR再分析资料,采用对历史个例进行合成分析的方法,研究了异常降水中心分别位于长江以南区域的江南型和长江-淮河流域的江淮型低频雨型的季节内水汽输送特征.研究表明,江南型的总水汽输送主要来源于孟加拉湾,并经中南半岛和南海输入江南区域;江淮型的总水汽输送主要直接来源于南海,但水汽源地主要为印度季风区.对于水汽输送异常,江南型和江淮型具有明显不同的特征.江南型的水汽输送异常主要来源于热带西太平洋-南海,中纬度西风带和中高纬度南下的水汽输送异常的贡献次之;而江淮型的水汽输送异常主要来源于热带和副热带西太平洋,中纬度西风带水汽输送异常的贡献次之.另外,水汽输送异常对江南型的区域总水汽收支的贡献约为50%,而对江淮型的区域总水汽收支的贡献高达70%左右.因此,虽然总水汽输送主要取决于气候平均水汽输送,但是,水汽输送异常与气候平均水汽输送对江南型和江淮型的水汽供应具有相同甚至更为重要的贡献.特别是对于江淮型,区域总水汽收支主要取决于水汽输送异常的贡献,而水汽输送异常的变化较平均水汽输送更为复杂,这有可能是江淮流域汛期降水预报较为困难的原因之一. 相似文献
625.
This paper describes and analyses a hillslope–channel slope failure event that occurred at Wet Swine Gill, Lake District, northern England. This comprised a hillslope slide (180 m3, c. 203 ± 36 t), which coupled with the adjacent stream, resulting in a channelized debris flow and fluvial flood. The timing of the event is constrained between January and March 2002. The hillslope failure occurred in response to a rainfall/snowmelt trigger, on ground recently disturbed by a heather moorland fire and modified by artificial drainage. Slide and flow dynamics are estimated using reconstructed velocity and discharge values along the sediment transfer path. There is a rapid downstream reduction in both maximum velocity, from 9·8 to 1·3 m s?1; and maximum discharge, ranging from 33·5 to 2·4 m3 s?1. A volumetric sediment budget quantified a high degree of coupling between the hillslope and immediate channel (~92%: 167 m3), but virtually all of the sediment was retained in the first‐order tributary channel. Approximately 44% (81 m3) of the slide volume was retained in the run‐up deposit, and termination of the debris flow prior to the main river meant that the remainder did not discharge into the fluvial system downstream. These results suggest poor transmission of sediment to the main river at the time of the event, but importantly an increase in available material for post‐event sediment transfer processes within the small upland tributary. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
626.
ChangLiang Yin TanDong Yao LiDe Tian DongNian Liu WuSheng Yu DongMei Qu 《中国科学D辑(英文版)》2008,51(7):966-975
Oxygen stable isotope of atmospheric water vapor is widely used to study the modern process of climate. Atmospheric water
vapor samples were collected at Dlingha, northeast of Tibetan Plateau during the period from July 2005 to February 2006. The
variation of δ
18O and the relationships between δ
18O and both the temperature and specific humidity are analyzed in this paper. Results show that the seasonal variation of δ
18O of atmospheric water vapor at Delingha is remarkable with higher δ
18O in summer and lower δ
18O in winter. The temporal variation of vapor δ
18O shows obvious fluctuations, with magnitude of over 37‰ The daily variation of the δ
18O is highly correlated with air temperature. The relationship between δ
18O and atmospheric water vapor content is complex. Study shows that δ
18O of atmospheric water vapor is positively correlated with specific humidity in winter in seasonal scale and inversely correlated
with specific humidity in summer rainy period. The δ
18O values of atmospheric water vapor are lower than those of precipitation at Delingha, and the average difference is 10.7‰
Variations of δ
18O of atmospheric water vapor is also found to be affected by precipitation events, The model results show that the precipitation
effect could have caused the vapor δ
18O in the raining season to lower by 7% in average in July and August.
Supported by the National Natural Science Foundation of China (Grant Nos. 40671043, 40571039 and 40771048) and National Basic
Research Program of China (Grant No. 2005CB422002) 相似文献
627.
628.
629.
Mass and heat transfer occurring across phase-interfaces in multi-phase flow in porous media are mostly approximated using equilibrium relationships or empirical kinetic models. However, when the characteristic time of flow is smaller than that of mass or heat transfer, non-equilibrium situations may arise. Commonly, empirical approaches are used in such cases. There are only few works in the literature that use physically-based models for these transfer terms. In fact, one would expect physical approaches to modeling kinetic interphase mass and heat transfer to contain the interfacial area between the phases as a variable. Recently, a two-phase flow and solute transport model was developed that included interfacial area as a state variable [36]. In that model, interphase mass transfer was modeled as a kinetic process. 相似文献
630.
The study developed an integrated reflectance model combining radiative transfer and geometric optical properties in order
to inverse leaf area index (LAI) of semiarid natural grasslands. In order to better link remote sensing information with land
plants, and facilitate regional and global climate change studies, the model introduced a simple but important geometrical
similarity parameter related to plant crown shapes. The model revealed the influences of different plant crown shapes (such
as spherical, cylindrical/cuboidal and conic crowns) on leaf/branch angle distribution frequencies, shadow ground coverage,
shadowed or sunlit background fractions, canopy reflectance, and scene reflectance. The modeled reflectance data agreed with
the measured ones in the three Leymus chinensis steppes with different degradation degrees, which validated the reflectance model. The lower the degradation degree was,
the better the modeled data agreed with the measured data. After this reflectance model was coupled with the optimization
inversion method, LAI over the entire study region was estimated once every eight days using the eight-day products of surface
reflectance obtained by multi-spectral Moderate-Resolution Imaging Spectroradiometer (MODIS) during the growing seasons in
2002. The temporal and spatial patterns of inversed LAI for the steppes with different cover degrees, swamps, flood plains,
and croplands agreed with the general laws and measurements very well. But for unused land cover types (sands, saline, and
barren lands) and forestlands, totally accounting for about 10% of the study region, the reasonable LAI values were not derived
by inversing, requiring further revising of the model or the development of a new model for them.
Supported by the National Natural Science Foundation of China (Grant No. 30500076), the National Basic Research Program of
China (Grant No. 2007CB714407), and the President Foundation of Graduate University of Chinese Academy of Sciences (Grant
No. YZJJ200205) 相似文献