排序方式: 共有16条查询结果,搜索用时 140 毫秒
11.
12.
To study how global warming and eutrophication a ect water ecosystems, a multiplicative growth Monod model, modified by
incorporating the Arrhenius equation, was applied to Lake Taihu to quantitatively study the relationships between algal biomass and
both nutrients and temperature using long-term data. To qualitatively assess which factor was a limitation of the improved model,
temperature variables were calculated using annual mean air temperature (AT), water temperature (WT), and their average temperature
(ST), while substrate variables were calculated using annual mean total nitrogen (TN), total phosphorus (TP), and their weighted
aggregate (R), respectively. The nine fitted curves showed that TN and AT were two important factors influencing algal growth; AT
limited growth as algal photosynthesis is mainly carried out near the water surface; N leakage of phytoplankton and internal phosphorus
load from sediment explains why TN was the best predictor of peak biomass using the Monod model. The fitted results suggest that
annual mean algal biomass increased by 0.145 times when annual mean AT increased by 1.0°C. Results also showed that the more
eutrophic the lake, the greater the e ect AT had on algal growth. Subsequently, the long-term joint e ect of annual temperature increase
and eutrophication to water ecosystems can be quantitatively assessed and predicted. 相似文献
13.
广州市PM_(10)与气象要素的关系分析 总被引:5,自引:1,他引:4
广州的PM10污染状况较为严重.PM10是大气颗粒物中对环境和人体健康危害最大的一类,PM10与医院就诊率、呼吸器官疾病发病率乃至死亡率等关系密切.PM10污染与气象条件关系密切,研究气象条件对PM10污染的影响,对改善城市空气质量条件有重要意义.文章利用2001~2004年广州市PM10和同期地面气象要素的监测资料,定量分析PM10与降雨量、相对湿度、平均温度和气压之间的关系:不同等级的降雨对PM10污染均有一定的清除作用;PM.0日平均质量浓度的改变量随着降雨量的增大而增大;1mm降雨量对PM10的清除能力按春、夏、秋、冬依次递增.春、夏、秋三个季节均为当日平均相对湿度低于季平均相对湿度时容易出现PM10污染天气,冬季则相反.春、秋两季均为当日平均气温在季平均值附近徘徊时,较易出现PM10污染,冬季则相反,夏季较少出现PM10污染.较高气压下PM10污染日的出现频率明显高于非污染日. 相似文献
14.
15.
<正>目前,对气候变化问题的认识已有大量科学证据,国际社会也基本就气候变化问题的科学性达成共识,但也仍存在一些质疑的声音。厘清对气候变化科学性及其不确定性的认知,有利于进一步取得科学共识,坚定积极应对气候变化、走低碳发展道路的方向。本文将试图从气候变化的观测事实和归因、气候变化问题的影响和风险、气候变化科学认识的局限性和不确定性等方面对气候变化问题的科学性进行浅析。 相似文献
16.
为研究飞机货舱火灾发展至轰燃的内在规律,在1/4体积标准飞机货舱内开展了一系列火灾轰燃试验。以单壁瓦楞纸箱被引燃作为轰燃发生的判据,研究了油盘尺寸和燃料种类对轰燃的影响,通过对货舱上部热烟气层平均温度、地板所受辐射热通量、燃料热释放速率及烟气体积分数的分析,探讨了轰燃发生的临界条件和表现形式。结果表明:油盘尺寸的增大提高了轰燃发生的可能性和轰燃的剧烈程度,在达到引发轰燃所需的临界油盘尺寸后,继续增大油盘尺寸会使轰燃发生的时间提前;引发飞机货舱轰燃所需的临界条件为,上部热烟气层平均温度达到456℃,地板所受辐射热通量达到14.3 kW/m2;此外,通过对轰燃所需的临界油盘尺寸与燃料热物性参数的拟合,发现轰燃所需的临界油盘尺寸正比于燃料的蒸发热,反比于燃料的燃烧热。 相似文献