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971.
我国云南腾冲地区地热资源丰富,对地热资源进行定量的预测评价势在必行。而以遥感为手段进行地表温度的反演是地热研究的重要方法。本文利用ETM数据的Band6热红外通道,对工作区进行温度反演并通过消除阴影影响对反演温度进行修正使得温度差异较大的情况得到改善,减少了太阳照射造成的温差影响。结果表明,研究区地表温度分布主要有3个区域;通过温度反演结果与已知地热点叠加分析,选取14~21℃为进行地热预测评价的有利区间。 相似文献
972.
近年来,生猪养殖业陆续开展了生猪禁养工作。通过划定生猪禁养区域,对禁养区内的"散、小、乱"养猪场进行清拆和整顿,再引进大型现代化生猪养殖场来发展企业化、规范化的生猪养殖是整治工作的常见思路,需要精准的数据、科学的理论作为支撑。本文以广州市增城区为例,从生猪禁养范围图制作和专题数据统计两方面探讨了测绘技术在生猪养殖业环保整治工作中的应用。通过数据提取、缓冲区分析、叠加分析、面的差异运算、地图编制等测绘技术的综合应用,证实了其服务于生猪养殖业环保整治工作的实用性、高效性和科学性,为各省市开展生猪养殖业环保整治工作提供了翔实的参考资料。 相似文献
973.
爆炸防雹中可能动力机制的探讨 总被引:5,自引:2,他引:5
文中在进一步归纳观测现象和分析爆炸产物能力的基础上 ,提出了爆炸扰动气流和重力波破碎可以对气流产生显著影响的物理假说 ,并应用数值模式模拟了扰动气流对基本流的作用 ,得到的结果与物理假说所预期的相一致 ;也与过去的实验或试验结果相一致。这说明爆炸(瞬时 )产生扰动场 ,扰动场 (维持一段时间 )再与基本场相互作用来影响基本流 (更长维持时间 ) ,看来这可能是爆炸影响基本流的主导途径 相似文献
974.
975.
青藏高原热力状况异常与长江中下游地区梅雨关系的相关分析及数值试验 总被引:8,自引:2,他引:8
利用观测资料对青藏高原热力状况与长江中下游地区梅雨进行统计分析, 发现两者存在一定的联系:旱、涝年青藏高原下垫面热力状况存在南北反相特征, 即当青藏高原下垫面前冬南侧偏暖 (冷)、北侧偏冷 (暖) 时, 对应长江中下游地区梅雨量易偏少 (多)。而且这种高原下垫面异常热力状况具有持续性, 可以持续维持到夏季。在此基础上, 设计了两组敏感性试验, 分别改变高原下垫面热力状况, 应用NCAR RegCM2区域气候模式进行数值模拟, 模拟结果可以较好的验证上述统计事实。 相似文献
976.
林志垒 《测绘与空间地理信息》2001,24(1):3-5
应用 1988年和 1992年福州市卫星图像 ,对福州市热岛效应进行动态研究 ,结果表明 :随着城市建设的发展 ,原热岛范围内高温区增加 ,热岛范围明显扩大 ,尤其是市区东部施展最快 ,在 1988~ 1992这 4年中福州的热岛范围向东扩展了约 15km2 ,同时热岛外围小热岛也不断涌现。在这些动态变化特征的基础上 ,本文分析了福州市热岛效应动态变化的原因以及减轻热岛效应影响的具体措施。 相似文献
977.
刘旭春 《测绘与空间地理信息》2001,24(3):47-48
分析了在测绘高新技术飞速发展条件下,非测量专业测量教学面临的诸多问题,并就一些关键性问题提出了自己的看法,仅供同行参考. 相似文献
978.
Feedback Mechanisms For The Atmosphere And Ocean Surface 总被引:4,自引:0,他引:4
Two kinds of feedback mechanisms in the coupling process between the atmosphere and ocean surface are identified in this paper. One is a negative feedback mechanism, which is effective in the dynamic interaction processes through momentum flux exchange. In this mechanism,the ocean extracts momentum from the atmosphere as a forcing field to generate waves, which decelerates atmospheric motions, lessening the intensity of synoptic systems. The second is a positive feedback mechanism, which is effective in the thermal interaction processes through heat flux exchange. This is a mechanism that is effective in the transport of sensible and latent heat fluxes to the atmosphere from the underlyingocean surface. As a result, the atmosphere obtains energy from the ocean, which intensifies atmospheric motions. For storm conditions typical of North Atlantic mid-latitudes, we consider these thermal and dynamical nteractions, the dominance of one over the other, and related implications for storm intensification. 相似文献
979.
A coupled atmosphere-ocean model developed at the Institute for Space Studies at NASA Goddard Space Flight Center (Russell et al., 1995) was used to verify the validity of Haney-type surface thermal boundary condition, which linearly connects net downward surface heat flux Q to air / sea temperature difference △T by a relaxation coefficient k. The model was initiated from the National Centers for Environmental Prediction (NCEP) atmospheric observations for 1 December 1977, and from the National Ocean Data Center (NODC) global climatological mean December temperature and salinity fields at 1° ×1° resolution. The time step is 7.5 minutes. We integrated the model for 450 days and obtained a complete model-generated global data set of daily mean downward net surface flux Q, surface air temperature TA,and sea surface temperature To. Then, we calculated the cross-correlation coefficients (CCC) between Q and △T. The ensemble mean CCC fields show (a) no correlation between Q and △T in the equatorial regions, and (b) evident correlation (CCC≥ 0.7) between Q and △T in the middle and high latitudes.Additionally, we did the variance analysis and found that when k= 120 W m-2K-1, the two standard deviations, σQ and σk△T, are quite close in the middle and high latitudes. These results agree quite well with a previous research (Chu et al., 1998) on analyzing the NCEP re-analyzed surface data, except that a smaller value of k (80 W m-2K-1) was found in the previous study. 相似文献
980.
Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results 总被引:59,自引:0,他引:59
Five test runs were performed to assess possible bias when performing the loss on ignition (LOI) method to estimate organic matter and carbonate content of lake sediments. An accurate and stable weight loss was achieved after 2 h of burning pure CaCO3 at 950 °C, whereas LOI of pure graphite at 530 °C showed a direct relation to sample size and exposure time, with only 40-70% of the possible weight loss reached after 2 h of exposure and smaller samples losing weight faster than larger ones. Experiments with a standardised lake sediment revealed a strong initial weight loss at 550 °C, but samples continued to lose weight at a slow rate at exposure of up to 64 h, which was likely the effect of loss of volatile salts, structural water of clay minerals or metal oxides, or of inorganic carbon after the initial burning of organic matter. A further test-run revealed that at 550 °C samples in the centre of the furnace lost more weight than marginal samples. At 950 °C this pattern was still apparent but the differences became negligible. Again, LOI was dependent on sample size.An analytical LOI quality control experiment including ten different laboratories was carried out using each laboratory's own LOI procedure as well as a standardised LOI procedure to analyse three different sediments. The range of LOI values between laboratories measured at 550 °C was generally larger when each laboratory used its own method than when using the standard method. This was similar for 950 °C, although the range of values tended to be smaller. The within-laboratory range of LOI measurements for a given sediment was generally small. Comparisons of the results of the individual and the standardised method suggest that there is a laboratory-specific pattern in the results, probably due to differences in laboratory equipment and/or handling that could not be eliminated by standardising the LOI procedure.Factors such as sample size, exposure time, position of samples in the furnace and the laboratory measuring affected LOI results, with LOI at 550 °C being more susceptible to these factors than LOI at 950 °C. We, therefore, recommend analysts to be consistent in the LOI method used in relation to the ignition temperatures, exposure times, and the sample size and to include information on these three parameters when referring to the method. 相似文献