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31.
32.
上海高温和低温气候变化特征及其影响因素 总被引:1,自引:0,他引:1
基于上海11个气象站逐日最高、最低气温、降水资料和西太平洋副热带高压(简称副高,下同)环流指数,分析了上海夏季高温和冬季低温的气候变化特征及其影响因素。结果表明,1873~2007年,上海高温日数表现为少-多-少-多的年代际变化,低温日数则表现为多-少的年代际变化。2001~2007年,上海年均高温日数、各级高温过程数和高温过程日数都最多,低温日数、低温过程数和低温过程日数都最少。1960~2007年,上海每年高温日数与当年夏季副高面积和强度指数显著正相关,低温日数与当年冬季副高面积和强度指数显著负相关。降水对上海极端气温有一定的缓解作用,上海高温日数与夏季降水量弱显著负相关,低温日数与冬季降水量显著负相关。上海高温过程数受城市化影响较大,其时间变化具有明显的城郊差异,低温过程数则受城市化影响较小。 相似文献
33.
Seasonal dependency of controlling factors on the phytoplankton production in Taihu Lake, China 总被引:1,自引:0,他引:1
In this study, 44 profiles of gross primary productivity(GPP) and sunlight, along with water temperature, Chlorophyll-a(Chla) and nutrients, were observed in Meiliang Bay of Taihu Lake, China, in the spring, summer, and fall seasons. Effects of water temperature, light,and nutrient concentration were examined in relation to the GPP-unit-Chla(GPP of algae per Chla). The results showed that the optimum temperature for the GPP of phytoplankton was 27.9°C, the optimal PNA-unit-Chla(photon number absorbed by phytoplankton per Chla) was 0.25(mol), and the HSCN-unit-Chla and HSCP-unit-Chla(half-saturation constants of nitrogen and phosphorus of algae per Chla) were 0.005(mg/L) and 0.0004(mg/L), respectively. The seasonal dependency of the effect of different factors on the GPP was analyzed. Compared with temperature and nutrients, light was found to be the most important factor affecting the GPP during the three seasons. The effect of temperature and nutrients on the GPP of phytoplankton has obvious seasonal change. In spring, temperature was the secondary factor affecting the GPP of phytoplankton, and the effect of nutrients may be negligible in the eutrophic lake on account of temperature limit, which showed that the GPP of algae was only affected by the physical process. In summer and fall, temperature didn't affect the GPP of algae, and the presence of nutrients was the secondary factor affecting the GPP of phytoplankton. From summer to fall, effect of phosphorus was weakened and effect of nitrogen was enhanced. 相似文献
34.
The purpose of this paper is to apply a stress model drawn from the literature to the relief and social service workers who have been active in refugee camps for a prolonged period of time. Working in difficult environments, social service workers deliver essential services to refugee populations around the world. A model of four work-stress determinants--tasks, management, appreciation and collaboration--was tested on 274 social workers in five regions of the Middle East (Jordan, Lebanon and Syria, as well as the occupied Palestinian territories of the Gaza Strip and the West Bank). Statistical fit indices were adequate but two relationships were statistically insignificant. The collaboration variable was dropped to create a modified model with tasks indirectly and management and appreciation directly affecting work-related stress. The five direct relationships and two indirect relationships of this modified model are consistent with stress theory, and all relationships--direct and indirect--are statistically significant. 相似文献
35.
匡玉芳 《长江流域资源与环境》1999,8(1):63-68
大麦是世界四大谷类作物之一,以适应性强、抗塑性强、抗逆性好、用途广而在世界各大洲广为种植。二次世界大战后,随着经济发展,大麦产量由60年代的9970.0万t增加到1994年的15872.8万T,长江 中游历来是我国大麦的主要种植之一,随着我国经济的发展,大麦生产经况愈下,成为我国进口量最大的农产品之一,其种植面积由1961年77.927万hm^2降为1995年的8.348万hm^2,与世界经济越发 相似文献
36.
长江中下游地区旱涝气候年景和评定方法的研究 总被引:5,自引:0,他引:5
采用经过修改的Z值指标,利用1961~1995年5~9月的总降水量,建立了长江中下游地区7省市逐年的旱涝等级序列;同时通过计算干旱指数、洪涝指数和旱涝综合指数,对长江中下游地区的旱涝和旱涝气候年景进行了评定,初步实现了气候年景评定从定性向定量的转变,并得到一致的可比的历史序列。 相似文献
37.
38.
Determinants of the Willingness-to-Participate in an Environmental Intervention in a Beirut Neighborhood 总被引:1,自引:1,他引:0
Participatory environmental management can empower communities and enhance the sustainability of environmental interventions.
However, existing power structures and inequalities along class, gender, or ethnic lines could prevent part of the community
from accessing the full benefits of the intervention. An analysis of determinants of the willingness-to-participate in an
environmental intervention in a Beirut neighborhood is conducted. Socioeconomic, health-risk distribution, and perception
of community efficacy are used as predictors. A randomly selected sample of residents was surveyed. Respondents were asked
to specify the frequency with which they were willing to be involved in an intervention to address priority environmental
problems in the neighborhood. Bivariate and multivariate ordinal regression analyses were conducted. Tests of significance
were based on the 95% confidence intervals (CI) of the odds ratio (OR). Males versus females (OR = 4.89, P < 0.001), respiratory patients versus nonsufferers (OR = 5.65, P < 0.001), tenants versus house owners (OR = 2.98, P < 0.01), and the less educated versus the more educated (OR = 2.42, P < 0.05) were significantly more likely to be willing to participate. The reluctance of female community members to participate
might be a major hindrance to community-based environmental protection and special strategies must be devised to overcome
it. On the other hand, respondents suffering from an illness perceived to be related to environmental toxins are likely to
be strong participants in environmental conservation efforts. Finally, the study yielded no evidence that belief or lack of
it in the efficacy of community action is a good predictor of the willingness-to-participate in such action. 相似文献
39.
以南水北调中线工程水源区为研究区域,采用1961~2007年9个气象站点气象观测数据和黄家港水文站实测径流资料,以FAO彭曼蒙特斯公式和水文模拟法为标准分别对多种潜在蒸散发计算方法和实际蒸散发计算方法进行比较研究,并分析了陆面蒸散发的影响因素。研究表明:南水北调中线工程水源区存在“蒸发悖论”现象,Priestley Taylor公式计算结果偏大,但与FAO 彭曼蒙特斯公式存在良好的相关关系,在气象资料较少时可以考虑建立相关方程进行推求。傅抱璞公式与水文模拟法计算结果较为接近,相关关系最优。潜在蒸散发与平均温度、气温日较差、实际水汽压、降雨量、风速、净太阳辐射、日照时数呈正相关,而实际蒸散发与平均温度、气温日较差、实际水汽压、降雨量、净太阳辐射、日照时数呈正相关,与风速呈负相关。净太阳辐射是影响陆面蒸散发的核心因素 相似文献
40.
本文阐述了我国的污水处理方式现状,认为发展分散式废水处理系统,坚持分散处理和集中处理相结合,中心城区以集中处理外排为主、郊区以分散处理为主的方式,将是提高我国污水处理率的发展趋势。 相似文献