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961.
????????????????y?????GOCE???????????10??60??ε?????????????????GOCE??гλ????в?????????????????????????????????з????????30°??Χ????????仯??????????GOCE??????????????B????(-75°, 250°)???????仯??-9.15 cm/a????B??????????????????? 相似文献
962.
Zongming Wang Yubo Zhang Bai Zhang Kaishan Song Zhixing Guo Dianwei Liu Fang Li 《中国地理科学(英文版)》2008,18(2):137-145
The landscape pattern of Da'an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape pattern and its spatial dynamics of Da'an County at the landscape level over the nearly 50-year span. Patch dynamics were examined according to land use and land cover change processes built from a series of images, as well as topographic maps, and temporal patterns built from landscape pattern metrics. The transition matrix of landscape patch types and changes of various landscape metrics were applied. The results showed that, from 1956 to 2000, the landscape within the study area had undertaken a complicated evolution in landscape structure and composition. The outstanding characteristic is that saline-alkali land increased and grassland decreased. As some smaller patches amalgamated, the heterogeneity of patch decreased. All those changes were the synthetic result of both climatic and anthropogenic influences, but the predominant factor was different in different parts. In the southern part of the study area, the landscape pattern changes resulted from the modification of climate obviously, while in the northern part, the landscape pattern changes were mainly caused by human activities, such as the conversion between farmland and saline-alkali land. This phenomenon showed that human activities played more important role in the north than in the south of Da'an County. 相似文献
963.
This paper presents the study on two continuous glacio-lacustrine sedimentary deposits, Laotanfang (3 597 m) and Shibantang (3 689 m) located on the southern and northern sides of Hulifang peak in Yunan, China. Environmental change indexes are constructed for each deposit, based on grain size, geochemical and pollen analysis, environmental magnetic susceptibility, and 14C dating. The study of climatic environmental change since the Holocene epoch in this region shows that the climate fluctuated at different stages during the early Holocene, that is, the climate was cool and wet during 8 4-7 7 ka, cold and wet during 7 7-6 5 ka, cold and dry during 6 5-4 7 ka, cool and wet during 4 7-2 1 ka, warm and wet during 2 1-1 0 ka, and warmer and wet since 1 ka. These findings reflect the overlapping influences of the southwest and southeast monsoons in different times during the Holocene in the north part of southwestern China are in accord with other Holocene climate change models in this part of China. 相似文献
964.
Method for evaluating the degrees of land use sustainability of mountainous county and its application in Yunnan Province,China 总被引:3,自引:1,他引:3
The evaluation of sustainable land use is the key issue in the field of studying the sustainable land utilization. In general analysis, the sustainable land use is evaluated respectively from its ecological sustainability, economic sustainability and social sustainability in China and other countries in recent years. Although this evaluation is an important work, it seems insufficient and hard to comprehensively reflect the whole degree of land use sustainability. Thus, to make up this deficiency, this paper brings forward the evaluation indexes, which make it possible to quantitatively reflect the whole degree of land use sustainability, namely, the concept of "degrees of overall land use sustainability" (Dos), and research and measurement development of the method of and calculation in Dos. Taking the evaluation of the degree of land use sustainability in county regions of Yunnan Province as the actual example for analysis, results are basically as follows:
1) The degree of land use sustainability (Dos) is the ration index to organically and systematically integrate the degree of ecological friendliness (DeF), the degree of economic viability (Dev) and the degree of social acceptability (Dsa), able to comprehensively reflect the whole sustainability degree of regional land use
2) Based on the value of Dos, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy.
3) The pract 相似文献
1) The degree of land use sustainability (Dos) is the ration index to organically and systematically integrate the degree of ecological friendliness (DeF), the degree of economic viability (Dev) and the degree of social acceptability (Dsa), able to comprehensively reflect the whole sustainability degree of regional land use
2) Based on the value of Dos, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy.
3) The pract 相似文献
965.
�ɶ���̨������������������ 总被引:9,自引:7,他引:9
2007??4???2008??6?£???FG5/232??FG5/214????????????????????????????????????????5?ξ???????????????ι????????????С???2??10 -8 ms -2??????t??????????????????????С???????????????????????????????????????2007??12????????????2007??4??????5??10 -8 ms -2?????????????????????仯?????????????????????????????δ????? 相似文献
966.
���ھ�������ʵ��۲�ȶ� 总被引:2,自引:0,他引:2
???FG5???????????????????????2008??1?????й??????????о?????3053????????????????????????о?????????????????FG5-214??FG5-232???н???????????????????????????????????????н????????????????????????????????????2~3????10 -8 ms -2?? 相似文献
967.
�봨8.0������ͬ���������α�ЧӦģ�� 总被引:7,自引:4,他引:7
???????λ??????????е???????????????????Ms8.0???????????????????仯?????????????????????λ????????????????????????α?仯?????????????????????????????????????????仯????,????????????????????????????????????α?????????????????????????????仯?????10??10 -8 ms -2???£??????????仯??????????50??10 -8 ms -2????????????????????????? 相似文献
968.
地下水位对定点形变观测干扰的抽水实验 总被引:3,自引:2,他引:3
抽水所造成的地下水位的变化会即时在局部范围内造成地表的形变,干扰定点地壳形变观测。在蓟县地震台进行的抽水实验表明:这种干扰的幅度与抽水水井到形变监测仪器的距离有关,也和抽水水井水位的最大降深有关。根据实验数据得到了抽水对定点形变观测的影响范围的经验公式。 相似文献
969.
基于融合技术的结构性栅格时空数据平台的构建 总被引:6,自引:0,他引:6
时空数据融合是当前研究地理现象空间格局的数据存储、处理方法与有效途径。在构建国家资源环境时空数据平台过程中 ,我们设计了基于 1 km栅格单元的土地利用现状与变化数据库。这种时空数据表达方式的优点 :(1 )在保持面积信息不损失情况下明显减少了数据存储量 ,并且满足区域分析的空间尺度要求 ;(2 )便于多时间序列的数据存储与变化分析 ,以及变化专题信息提取与结果显示 ;(3)有利于区域土地利用变化环境背景与驱动力分析 ,可以实现与其他多源数据的有效融合 ;(4 )从小尺度到大尺度的空间尺度转换非常便利 ,在空间聚合的基础上能够快速实现从区域分析扩大至国家尺度、全球尺度的分析。 相似文献
970.
松辽盆地中生代沉积基准面变化研究 总被引:6,自引:0,他引:6
利用地质资料研究来恢复沉积基准面变化。首先根据沉积物的分布规律、沉积构造、古生物组合及古生态、自生矿物和波基面等特征来获得古水深,然后利用对地层做脱水压实校正获得沉积物原始厚度。对湖盆地区古水深和沉积物原始厚度累加起来就可得到沉积基准面变化曲线。沉积基准面变化曲线为在松辽盆地中进行地层对比提供了依据。 相似文献