生态系统服务时空演化的非线性影响因子——以钱塘江流域为例

为深入探究不同尺度、不同类别影响因素对不同类型生态系统服务的影响程度和复杂关系,本文测定了钱塘江流域7项生态系统服务的时空变化,并通过随机森林模型识别了各单项生态系统服务不同尺度自然环境因素和社会经济因素的影响程度和相对重要性,并评估了主导影响因素的边际效应.结果表明：2010~2017年,各单项生态系统服务在时空变化上具有明显的空间分异特征;不同类型生态系统服务受不同尺度自然环境因素和社会经济因素的共同影响,但其影响程度存在明显差异,格网尺度、自然环境因素的影响相对较大,建设用地、耕地及与其直接相关的社会经济因素的变化改变和塑造着生态系统服务的演化过程;主导影响因素与各单项生态系统服务之间存在复杂的非线性关系,各影响因素指标的变化对各年份生态系统服务具有非平稳的影响,如建设用地增加初期对多项生态系统服务的影响更为复杂和剧烈.     

Dry reforming of methane over oil palm shell activated carbon and ZSM-5 supported cobalt catalysts

In this study, cobalt supported oil palm shell activated carbon (Co/OPS-AC) and ZSM-5 zeolite (Co/ZSM-5) catalysts have been prepared for dry reforming of methane. Cobalt ratios of 6.0 and 14.0 wt% were deposited via wet impregnation method to the OPS-AC and ZSM-5 catalysts. The catalysts were characterized by XRD, N₂ adsorption--desorption isotherms, BET surface area, SEM, FESEM-EDX, TPR-H₂, and TPD-NH₃. The dry reforming of methane was performed using a micro reactor system under the condition of 10,000 ml/h.g-cat, 3 atm, CH₄/CO₂ ratio of 1.2:1.0 and temperature range from 923 K to 1023 K. The gaseous products were analyzed by gas chromatography (GC) with thermal conductivity detector (TCD) and further quantified to determine the conversions of CH₄ and CO₂, and the yields of CO and H₂. Experimental results revealed both catalysts exhibited lower conversions of CO₂ and CH₄ with the increase in temperature from 923 K to 1023 K. The reduced conversions may be due to the formation of carboneous substance on the catalyst known as coking. Comparatively, Co/OPS-AC gave higher conversions of CO₂ and CH₄ as well as higher yields of H₂ and CO as it has a higher surface area than Co/ZSM-5 which subsequently rendered higher activity for the reforming of methane. With the increasing cobalt loadings and reaction temperature, OPS-AC(14) catalyst exhibited improved activity and H₂/CO ratio. Based on these results, cobalt supported OPS activated carbon catalyst was suggested to be more effective for CO₂ and CH₄ conversions.     

横断山区干旱河谷大气水资源变化特征与演变趋势研究

利用横断山区干旱河谷内24个气象站逐月降水、气温等观测资料,依托高桥浩一郎陆面蒸发公式,计算了干旱河谷区陆面蒸发、可利用降水等水资源分量,并分析了各分量的未来演变趋势。结果表明:干旱河谷区年均降水量723.7mm,而年均蒸发量高达479.5mm,降水量中有超过84.89%因蒸发而损耗;大气水资源分量P、E及PE季节变化非常明显,夏季各分量最大,多年平均值达404.9mm、239.9mm和164.8mm,各占全年的55.94%、50.04%和67.51%,而冬季各分量最小,占全年的比例也相应最小,仅为2.96%、4.06%和0.79%;大气水资源各分量年代际差异很大,20世纪60年代可利用水资源丰富,70年代相对偏少,80和90年代逐渐增加,进入21世纪后又呈现为偏少特征;未来干旱河谷区的降水量维持减少的概率较转向增加的概率要小,蒸发量将依然维持增加的趋势,而可利用水资源量会继续维持减少的倾向。     

甘肃张掖市退耕还林(草)工程影响综合评价

利用抽样调查和收集资料得到的数据,对张掖市实施退耕还林（草）工程的影响从社会、经济和生态三个方面进行了评价。结果表明：张掖市退耕还林（草）社会可持续性的评价结果为“较好”;2002—2004年的退耕还林（草）工程在三年内给农户带来了17229．62万元的纯收入;通过三年的退耕还林（草）,能增加植物碳量累积（NPP）170658．11t,NEP总量增加44544．94t。同时,还针对退耕还林（草）政策的完善提出建议：希望继续增加退耕还林（草）面积,在今后的退耕还林（草）工程中安排合理的还草面积,增加退耕还林（草）工程的配套费用。政府有关部门应切实解决退耕农户关心的问题。     

干气溶胶复折射率的参数化方案

基于成都市2017年10~12月WS600一体式气象站、AURORA-3000积分浊度计、AE-31黑碳仪以及GRIMM180环境颗粒物监测仪的地面逐时观测数据,结合Mie散射理论数值改进算法与免疫进化算法反演了550nm波长处干气溶胶复折射率（DACRI）的实部（n_re）和虚部（n_i）.通过分析DACRI反演结果与颗粒物质量浓度之比（BC/PM₁,BC/PM_2.5,BC/PM₁₀,PM₁/PM_2.5,PM₁/PM₁₀和PM_2.5/PM₁₀）之间的相关性,利用逐步线性回归方法分别构建了n_re和n_i的参数化方案. n_re和n_i的参数化方案拟合值与实测值之间的相关系数（R）分别为0.54和0.85（P<0.0001）,平均相对误差（MRE）分别为2.31%和15.18%.此外,利用该参数化方案计算的DACRI模拟了一次灰霾演化过程中干气溶胶的散射系数b_sp和吸收系数b_ap,其模拟值与实测值之间的相关系数分别为0.98和0.91（P<0.0001）,平均相对误差分别为7.43%和14.97%.     

我国南方两个典型森林生态系统的硫、氮和汞沉降量

利用混合降水采样器,对江西千烟洲和湖南会同两个森林生态站的大气硫、氮和汞的湿沉降和穿透水沉降进行了为期1 a的观测.在2013-12~2014-11的观测期间,千烟洲站降水中的SO_4~(2-)-S、NO_3~--N、NH_4~+-N和Hg的体积加权平均质量浓度分别为1.89 mg·L~(-1)、0.957 mg·L~(-1)、0.401 mg·L~(-1)和12.5 ng·L-1,而穿透水中的平均浓度分别为2.39 mg·L~(-1)、1.18 mg·L~(-1)、0.897 mg·L~(-1)和22.2 ng·L-1,穿透水浓度较降水有不同比例的增加.会同站穿透水中的元素平均浓度则分别为2.93mg·L~(-1)、1.60 mg·L~(-1)、0.502 mg·L~(-1)和22.0 ng·L-1.基于穿透水的千烟洲站大气硫、氮和汞的沉降量分别为3.56g·(m2·a)-1、3.02 g·(m2·a)-1和30.6μg·(m2·a)-1,会同站分别为6.18 g·(m2·a)-1、4.48 g·(m2·a)-1和37.3μg·(m2·a)-1,三者均在夏季达到最高.汞的干湿沉降量相当,而硫和氮的湿沉降量在总沉降量中占主导地位.与硫沉降和氮沉降主要来自人为源不同,自然源对汞沉降的贡献较明显,特别是在会同站.     

上海地区不同类和不同强度灰霾季节分布特征

主要采用美国宇航局(NASA)2007年1月-2010年11月CALIPSO卫星搭载的正交极化云-气溶胶激光雷达(CALIOP)L1产品及地面气象观测资料,分析得到上海地区干霾和湿霾、不同强度灰霾天气的季节分布特征,并重点研究了发生干霾时气溶胶散射强度、粒子规则性和尺度大小随季节的变化规律。结果表明:灰霾的发生具有较明显的季节性,春季为干霾高发期,其次是夏冬季;夏冬两季轻度以上干霾发生比例均大于春季与秋季;大气中主要以小尺度、较规则的气溶胶粒子为主;干霾时,气溶胶粒子和不同量级色比值所占比例季节变化不大;夏季发生干霾时小尺度粒子所占比例最大。     

Simulating the potential for ecological restoration of dryland forests in Mexico under different disturbance regimes

Examining the potential for ecological restoration is important in areas where anthropogenic disturbance has degraded forest landscapes. However, the conditions under which restoration of degraded tropical dry forests (TDF) might be achieved in practice have not been determined in detail. In this study, we used LANDIS-II, a spatially explicit model of forest dynamics, to assess the potential for passive restoration of TDF through natural regeneration. The model was applied to two Mexican landscapes under six different disturbance regimes, focusing on the impact of fire and cattle grazing on forest cover, structure and composition. Model results identified two main findings. First, tropical dry forests are more resilient to anthropogenic disturbance than expected. Results suggested that under both a scenario of small, infrequent fires and a scenario of large, frequent fires, forest area can increase relatively rapidly. However, forest structure and composition differed markedly between these scenarios. After 400 years, the landscape becomes increasingly occupied by relatively shade-tolerant species under small, infrequent fires, but only species with both relatively high shade tolerance and high fire tolerance can thrive under conditions with large, frequent fires. Second, we demonstrated that different forms of disturbance can interact in unexpected ways. Our projections revealed that when grazing acts in combination with fire, forest cover, structure and composition vary dramatically depending on the frequency and extent of the fires. Results indicated that grazing and fire have a synergistic effect causing a reduction in forest cover greater than the sum of their individual effects. This suggests that passive landscape-scale restoration of TDF is achievable in both Mexican study areas only if grazing is reduced, and fires are carefully managed to reduce their frequency and intensity.     

塔里木油田三甘醇脱水装置参数优化研究

文章通过三甘醇脱水工艺的第三套三甘醇注醇量调整,第三套再生温度的调节、汽提气注入量调整、贫液进塔温度调整运行参数的优化,得出:当三甘醇脱水工艺循环量在3840kg/h左右时,再生效果最好,贫液浓度最高,所获得的干气水露点最低;三甘醇脱水工艺再生温度在190～200℃之间温度越高,再生效果越好;三甘醇脱水工艺再生装置在汽提气量30Nm3/h左右时,再生效果最好,贫液浓度最高,所获得的干气水露点最低。     

ABC干粉抑制瓦斯爆炸的实验研究

为测定ABC干粉对瓦斯爆炸的抑制作用,采用容积为20L的近球形抑爆实验系统,粒径为20.76μm,主要成分为高聚合度磷酸铵盐的ABC干粉进行瓦斯抑爆实验。实验结果表明：ABC干粉的添加能够降低瓦斯爆炸的压力;粉体浓度为0.10g/L时,抑爆效果最好;粉体的抑爆效果,不仅与粉体浓度有关,还与爆炸性混合气体中的甲烷浓度有关;点火延迟时间越长,粉体抑爆效果越差。