Hydrogeologic controls on summer stream temperatures in the McKenzie River basin,Oregon     

Christina Tague  Michael Farrell  Gordon Grant  Sarah Lewis  Serge Rey 《水文研究》2007,21(24):3288-3300

Stream temperature is a complex function of energy inputs including solar radiation and latent and sensible heat transfer. In streams where groundwater inputs are significant, energy input through advection can also be an important control on stream temperature. For an individual stream reach, models of stream temperature can take advantage of direct measurement or estimation of these energy inputs for a given river channel environment. Understanding spatial patterns of stream temperature at a landscape scale requires predicting how this environment varies through space, and under different atmospheric conditions. At the landscape scale, air temperature is often used as a surrogate for the dominant controls on stream temperature. In this study we show that, in regions where groundwater inputs are key controls and the degree of groundwater input varies in space, air temperature alone is unlikely to explain within-landscape stream temperature patterns. We illustrate how a geologic template can offer insight into landscape-scale patterns of stream temperature and its predictability from air temperature relationships. We focus on variation in stream temperature within headwater streams within the McKenzie River basin in western Oregon. In this region, as in other areas of the Pacific Northwest, fish sensitivity to summer stream temperatures continues to be a pressing environmental issue. We show that, within the McKenzie, streams which are sourced from deeper groundwater reservoirs versus shallow subsurface flow systems have distinct summer temperature regimes. Groundwater streams are colder, less variable and less sensitive to air temperature variation. We use these results from the western Oregon Cascade hydroclimatic regime to illustrate a conceptual framework for developing regional-scale indicators of stream temperature variation that considers the underlying geologic controls on spatial variation, and the relative roles played by energy and water inputs. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Reduced rates of primary production in the Columbia River Estuary following the eruption of Mt Saint Helens on 18 May 1980     

Bruce E. Frey  J.Rubén Lara-Lara  Lawrence F. Small 《Estuarine, Coastal and Shelf Science》1983,17(2):213-218

The eruption of Mt Saint Helens on 18 May 1980 resulted in a massive increase in suspended particulate material in the Columbia River Estuary, producing a substantial increase in light attenuation. Since photosynthesis in the estuarine water column is partly controlled by the depth of light penetration in the water, photosynthesis was reduced by about 75% during the period of increased turbidity. It took about five weeks for the estuary to clear. Although primary production within the estuarine water column was greatly diminished during this period, the flux of particulate carbon through the estuary was high, and the total production we estimate to have been lost amounted to only about 2% of the total particulate carbon flux just after the eruption. That the high levels of turbidity in the estuary did not induce a severe fall in the phytoplankton population is evidence that phytoplankton biomass concentrations in the Columbia River Estuary are mostly a function of import from the Columbia River, rather than a function of in situ production.  相似文献   

The spatial division of industries of the pearl river delta in the 1990s: Characteristics and trends     

Yong-jian Xu  Xiao-pei Yan  Xue-qiang Xu 《中国地理科学(英文版)》2001,11(1):63-69

The article analyzed the spatial division of industries of the Pearl River Delta (PRD) in the 1990s, a period that witnessed the deepening of the reform and opening policies and continued rapid development of the region. By adopting the index of specialization, the extent of specialization, its change and its spatial distribution in the region are measured and demonstrated. The research revealed that, despite the trend of more balanced development of the secondary sector between the PRD and the rest of the province, in the PRD, it is the unbalanced development that dominated and the spatial division of the secondary sector has been shaped. The tertiary industry has also been experiencing unbalance development and the spatial division of the tertiary sector has been emerging, its extent of concentration appearing even more evident than that of the secondary sector. The author also discussed the linkage between the spatial division of the two sectors. In the end of the paper, the trends of the spatial division of the industries in the PRD are forecasted. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 49831030). Biography: XU Yong-jian (1972 – ), female, a native of Changsha City, Ph. D.. Her research interest includes urban geography.  相似文献   

PROBLEMS　OF　THE　AQUATIC　ENVIRONMENT　AND　COUNTERMEASURES　IN　RAPID　ECONOMIC　DEVELOPMENT　IN　THE　ZHUJIANG　RIVER　DELTA     

温琰茂  程国佩 《中国地理科学(英文版)》1995,(1)

ＰＲＯＢＬＥＭＳＯＦＴＨＥＡＱＵＡＴＩＣＥＮＶＩＲＯＮＭＥＮＴＡＮＤＣＯＵＮＴＥＲＭＥＡＳＵＲＥＳＩＮＲＡＰＩＤＥＣＯＮＯＭＩＣＤＥＶＥＬＯＰＭＥＮＴＩＮＴＨＥＺＨＵＪＩＡＮＧＲＩＶＥＲＤＥＬＴＡ￥ＷｅｎＹａｎｍａｏ（温琰茂）；ＣｈｅｎｇＧｕｏｐｅｉ...  相似文献   

长江上游防护林体系建设要点     

钟祥浩  程根伟  杨定国  陶和平 《山地学报》1991,(2)

本区防护林体系的建设目标是:改善生态环境,发展山区经济。人口稠密区防护林体系建设成败的关健在于:能否掌握生态生产双重功能,是否具有生态社会经济三大效益。为此进行了防护林体系分类,提出了林种的生态功能指标和生产功能指标。防护林体系的生态经济分区要研究生态经济系绽的地域差异,有助于发挥各个林种的生态生产双重功能,是建设防护林体系的重要途径,为合理布局提供科学依据。  相似文献   

THE DISCOVERED DEEP BURIED LAKE ICE IN SOURCE REGION OF THE HUANGHE RIVER     

王绍令  李位乾 《中国地理科学(英文版)》1993,3(3):247-254

The 4.45 m-thick pure ice lens have been discovered firstly at depth from 19.81 -24.26 m in the bore No.6, which locates in north bank of the Ngoring Lake. In source region of the Huanghe (Yellow) River, 14C dating, X -ray diffraction, pollen analysis, micropalaeontology, chemical components, environmental isotope 2H, 3H, 18O and freezing point of the ice and water samples from the bore have been tested and microorganism in the ice have been also appraised with microscope. Combined with the research on geomorphy and Quaternary around the lake, the ice lens are determined as a kind of deep-buried lake ice, formed in 35,030-45,209 yr.B.P., and annual mean air temperature was about -10℃ during that time.  相似文献   

Primary fish survey in the Huanghe River estuary   总被引：2，自引：0，他引：2  

Yang Jiming  Wang Cunxin 《中国海洋湖沼学报》1993,11(4):368-374

The survey in the Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cold-temperate species (15.3%). The seasonal changes of fish species, density and biomass are obvious. The total biomass is highest (7 699t) in August and lowest (489 t) in January.Setipinna taty has mean density of 9 278 indiv/km², and is the most important species constituting 25.5% of the total weight of fish caught.Trichiurus haumela was a dominant species in the 1950s, but no one was caught in this survey. There were obvious changes of the dominant fish species during the recent three decades. The demersal fish biomass has dropped greatly to only 1/10 in over 50 years since 1930. Contribution No. 2210 from the Institute of Oceanology, Academia Sinica.  相似文献   

THE PROTECTION OF THE ECOLOGIC ENVIRONMENT OF THE GREEN CORRIDOR IN THE LOWER REACHES OF THE TARIM RIVER     

程其畴 《中国地理科学(英文版)》1992,2(1):74-79

The Green Corridor in the lower reaches of the Tarim River is not only a unique natural landscape in desert but also an important passageway. Nowadays, the ecologic environment of the corridor is getting worse and worse due to man's economic activities and the lack of knowledge of the importance of the environment, which is one of is the three environment problems in Xinjiang. The corridor is in great need of planning and managing.  相似文献   

黄河上游及源头区生态环境质量综合评价   总被引：2，自引：0，他引：2  

卢中正邱少鹏  高会军 《地球信息科学学报》2003,5(1):11-15

本文简要介绍了利用遥感和地理信息系统技术进行黄河上游及源头区生态环境质量综合评价中,评价因子的获取及其分值和权值的确定,评价模型的建立及评价等级的划分。评价结果表明,该区环境质量具有垂直分带规律,人类不合理的经济活动是影响环境质量的重要因素。  相似文献   

东江鲤鱼的生物学   总被引：1，自引：0，他引：1  

叶富良  罗平  叶星 《广东海洋大学学报》1992,(2)

东江鲤鱼年轮形成时期主要在2～8月,生长特点可用von Bertalanffy生长方程L_t=851[1-e~(-0.133(t+0.0394))]、W_t=19171.5[1-e~(-0.173(t+0.0394))]~3来表达;怀卵量3.1～63.563.5万粒,怀卵量与体长、体重的关系分别为F=5.14×10~(-2)L~2.6176、F=17905.43+138.86W;食物组成周年变化不明显。结合生物学资料,讨论了东江鲤鱼资源合理利用问题,提出最小捕捞年龄应在2龄以上,捕捞强度F=0.35左右。  相似文献