A General Model for Analyzing Data from Mark-recapture Experiments with an Application to the Pacific Halibut

A general model is developed to examine the patterns of the regional movement of tagged and released fish from mark-recapture experiments. It is a stochastic model that incorporates fishing mortality, natural mortality, fish movement, tag-shedding, and different rates of reporting. A likelihood function is constructed for estimating its parameters. We used this model to analyze data on the Pacific halibut from mark-recapture experiments conducted by the International Pacific Halibut Commission (IPHC), with a total of 36,058 releases from 1982 to 1986 and 5,826 recoveries from 1982 to 2000. We estimated their rates of movement among IPHC management areas, along with their instantaneous rates of natural and fishing mortalities. Our analysis revealed that fish movement was not significant among areas, with a resident probability of > 0.92. This lends support to the IPHC catch-at-age stock assessment model (which has no built-in movement components). The estimated instantaneous rate of natural mortality (0.198 year⁻¹) lies between that assumed in all IPHC stock assessments before 1998 (0.20 year⁻¹) and that from 1999 onwards (0.15 year⁻¹). The estimates of the instantaneous rates of fishing mortality were consistent with those from the IPHC stock assessment model. Received: April 2003 / Revised: May 2005     

Window Sensitivity Functions for Line Transect Sampling

L and width 2w, then by a selection of viewing window is meant a choice of w, with the intent being to search for optimal viewing windows, with the goal in mind of improving variances of estimators of population density, reducing sampling effort, while maintaining the property of unbiasedness. The notions of increasing window sensitivity (IWS) and decreasing window sensitivity (DWS) are introduced, and a method of deriving confidence intervals is discussed.     

ESTIMATING THE Q100 IN BRITISH COLUMBIA: A PRACTICAL PROBLEM IN FOREST HYDROLOGY1

ABSTRACT. Estimates of peak flows, with specified return periods, are needed in practice for the design of works that affect streams in forested areas. In the province of British Columbia (B.C.), Canada, the new Forest Practices Code specifies the 100-year instantaneous peak flow (Q100) for the design of bridges and culverts for stream crossings under forest roads; and many practitioners are engaged in making such estimates. The state of the art is still quite primitive, very similar to the state of urban hydrology 30 years ago, when popular estimating techniques were used with little consideration given to their applicability. Urban hydrology then evolved on a much more scientific basis, such that within about a 10-year period, standard approaches to design were developed. Forest hydrology should follow the same pattern, at least as far as estimating design flows is concerned. Popular present day design procedures include the rational method and other empirical approaches based on rainfall data, as use of the standard flood frequency approach is limited by the paucity of relevant flow data. Estimating procedures based on peak streamflow measurements and statistics are likely to evolve, and these will include distinctions for rain, snowmelt, and rain on snow floods. Guidelines will also be developed for selecting and applying appropriate procedures for particular areas.     

Mark-recapture estimators for dual frame population size of prominent nesting structures: the effect of uncertain detection probability

The combined mark-recapture and line transect sampling methodology proposed by Alpizar-Jara and Pollock [Journal of Environmental and Ecological Statistics, 3(4), 311–327, 1996; In Marine Mammal Survey and Assessment Methods Symposium. G.W. Garner, S.C. Amstrup, J.L. Laake, B.F.J. Manly, L.L. McDonald, and D.C. Robertson (Eds.), A.A. Balkema, Rotterdam, Netherlands, pp. 99–114, 1999] is used to illustrate the estimation of population size for populations with prominent nesting structures (i.e., bald eagle nests). In the context of a bald eagle population, the number of nests in a list frame corresponds to a pre-marked sample of nests, and an area frame corresponds to a set of transect strips that could be regularly monitored. Unlike previous methods based on dual frame methodology using the screening estimator [Haines and Pollock (Journal of Environmental and Ecological Statistics, 5, 245–256, 1998a; Survey Methodology, 24(1), 79–88, 1998b)], we no longer need to assume that the area frame is complete (i.e., all the nests in the sampled sites do not need to be seen). One may use line transect sampling to estimate the probability of detection in a sampled area. Combining information from list and area frames provides more efficient estimators than those obtained by using data from only one frame. We derive an estimator for detection probability and generalize the screening estimator. A simulation study is carried out to compare the performance of the Chapman modification of the Lincoln–Petersen estimator to the screening estimator. Simulation results show that although the Chapman estimator is generally less precise than the screening estimator, the latter can be severely biased in presence of uncertain detection. The screening estimator outperforms the Chapman estimator in terms of mean squared error when detection probability is near 1 wheareas the Chapman estimator outperforms the screening estimator when detection probability is lower than a certain threshold value depending on particular scenarios.     

天津市区夏季碳气溶胶特征及改进的二次有机碳估算方法

为更加准确地估算环境受体PM_2.5中SOC（二次有机碳）的质量浓度,于2015年6-8月利用在线监测仪器同步采集小时分辨率的PM_2.5及OC（有机碳）和EC（元素碳）样品数据,分析碳气溶胶的变化特征,并尝试运用改进的EC示踪法估算ρ（SOC）.结果表明:天津市区夏季ρ（PM_2.5）为（70.9±46.0）μg/m3,ρ（OC）和ρ（EC）分别为（7.6±3.1）（2.2±1.5）μg/m3,占ρ（PM_2.5）的11.8%±4.6%和3.1%±1.4%,OC/EC（质量浓度之比,下同）的平均值为4.0±2.0.ρ（OC）与ρ（EC）之间的Pearson相关系数（R）仅为0.66,说明OC和EC的来源较为复杂,SOC的产生可能是重要影响因素.ρ（NO₂）与OC/EC呈显著负相关（R=-0.47,P < 0.01）,并且OC/EC（4.0）相对较低,说明天津市区机动车可能对碳气溶胶具有重要影响.ρ（SO₂）与ρ（OC）、ρ（EC）的相关性较低（R均为0.33,P均小于0.01）,说明天津市区碳气溶胶可能受燃煤源的影响较低.改进的EC示踪法主要是利用O₃和CO、EC作为光化学反应和一次源排放的指标,并结合ρ（OC）、ρ（EC）和OC/EC的变化特征,逐步筛选一次排放源主导的时间段的ρ（OC）和ρ（EC）数据,然后利用最小二乘法拟合获得ρ（OC）和ρ（EC）的线性方程,最后进行ρ（SOC）和ρ（POC）（POC为一次有机碳）的估算.天津市区夏季ρ（SOC）的平均值为（2.5±2.0）μg/m3,分别占ρ（OC）和ρ（PM_2.5）的28.8%±15.0%和3.7%±3.6%;ρ（POC）的平均值为（5.2±1.7）μg/m3,分别占ρ（OC）和ρ（PM_2.5）的71.2%±15.0%和8.1%±5.2%,说明天津市区夏季有机碳的主要来源是一次排放源.研究显示,相比于EC示踪法,改进的EC示踪法估算的ρ（SOC）明显降低,ρ（POC）明显升高.AT（大气温度）对ρ（SOC）的影响较为显著,而WS（风速）对ρ（POC）的影响较为显著.      

利用集合均方根卡尔曼滤波反演重庆地区SO2源排放

传统的"自下而上"清单方法估算的排放清单,其数据的准确性和时效性存在较大局限.基于集合均方根卡尔曼滤波的源清单反演方法,结合WRF-CMAQ（天气研究和预报模式-公共多尺度空气质量模型）被用于对以清华大学编制的2010年MEIC（中国多尺度排放清单模型）排放清单为基础制作的重庆地区SO₂排放源进行反演试验以解决准确性和时效性问题,试验时间段为2014年10月15-31日,重庆主城17个环境空气质量国控监测点ρ（SO₂）小时观测资料用于反演及检验.结果表明:该方法能够反演重庆地区SO₂源排放量,随着反演次数增加,基于反演排放源预报的ρ（SO₂）预报误差持续减小,反演4次后预报误差达到比较低的稳定的水平,其均方根误差均低于20 μg/m3. 5次反演后SO₂源排放量用于2014年10月24-29日每天起始预报,其预报的站点、时间平均的均方根误差从100~400 μg/m3降至30 μg/m3以下.反演中应用局地化尺度减少集合取样误差影响,54与81 km两个局地化尺度反演结果对预报改善效果相当,表明主要影响重庆主城ρ（SO₂）的源排放位于主城及周边地区,也说明内源排放对重庆主城ρ（SO₂）起主要影响.反演后面源排放量主城区降幅约为30 kg/（d·km2）,周边地区减少10~20 kg/（d·km2）,主城区部分SO₂点源排放量降幅约为25 kg/（d·km2）,说明2010年MEIC排放清单高估了试验时段重庆地区的SO₂排放.      

上海市电子废弃物产生量预测与回收网络建立

以上海市为例,利用无容量限制的设施选址模型(UFCLP模型)建立了上海市电子废弃物(WEEE)回收网络,同时,为获得模型求解所需数据,根据1991～2012年的销售量对上海市2010～2017年彩电、冰箱、洗衣机、空调和电脑的废弃量进行了预测.结果表明,5种电子产品的总废弃量会从2010年的269.49×104台增至2017年的635.75×104台.最后,依据区域GDP、人口密度和区域面积等多因素对电子废弃物空间分布量进行了预测,并以此为基础选取了214个回收站候选点,使用SITATION软件对UFCLP模型进行求解,最终确定10个点作为拟建回收点,可实现未来上海市约76%的电子废弃物回收.该网络的建立对长三角地区和全国大中型城市电子废弃物回收都具有良好的示范作用.     

运用Jayaweera-Mikkelsen模型对太湖地区水稻田稻季氨挥发的模拟

运用密闭气室通气法测定了太湖地区典型水稻田lysimeter实验中肥料施用后的稻季氨挥发动态变化和总损失量,并使用Jayaweera-Mikkelsen氨挥发模型验证了测定结果.田间测定结果表明,施用普通尿素和控释尿素后的氨挥发显著不同,在水稻生育期普通尿素的氨挥发损失达施入N量的29%～35%,不同施N水平间差异显著;而不同用量的控释尿素的氨挥发损失则相对一致,仅为施入N量的5%.模型高估了生育期的氨挥发总量,特别是在普通尿素高挥发时期造成了较大偏差.对尿素处理,模型预测值与实测值的比率为2.95～4.19;对控释尿素处理,预测值对实测值有正负偏差,比率为1.19～1.40.运用预测值与实测值的级数商评价了模型的实用性.通过灵敏度分析,对模型中的参数NH 4-N的浓度进行了修正,引入了限制条件.修正后的模型能够很好地满足对高挥发量的预测,模拟结果比率为1.12～1.28.实测田面水中的NH 4-N浓度不能代表模型中参与计算的实际浓度,可能原因是藻类活动对NH 4-N浓度和氨挥发过程产生的影响.     

Development and application of a two-dimensional water quality model for the Daqinghe River Mouth of the Dianchi Lake

Water quality models are important tools to support the optimization of aquatic ecosystem rehabilitation programs and assess their efficiency. Basing on the flow conditions of the Daqinghe River Mouth of the Dianchi Lake, China, two-dimensional water quality model was developed in the research. The hydrodynamics module was numerically solved by the alternating direction iteration (ADI) method. The parameters of the water quality module were obtained through the in situ experiments and the lab analyses that were conducted from 2006 to 2007. The model was calibrated and verified by the observation data in 2007. Among the four modelled key variables that were water level, CODcr, NH3-N and PO4-P, the minimum value of the coefficient of determination (CoD) was 0.69, which mean the model performed reasonably well. The developed model was then applied to simulate the water quality changes at the downstream cross-section assuming that the designed restoration programs were implemented. According to the simulated results, the restoration programs could cut down the loads of CODcr and PO4-P about 15%, however, they would have very little effect on the NH3-N removal. Besides, the water quality at the outlet cross-section would be still in class V (3838-02), indicating more measures should be taken to further reduce the loads. The study demonstrated the capability of water quality models to support aquatic ecosystem restorations.     

基于树种蓄积量的中国森林VOC排放估算

以中国森林优势树种为对象,应用《全国森林资源统计》提供的林分优势树种蓄积量资料和Guenther提出的光温影响模型,估算各优势树种的VOC排放量,建立了中国森林生态系统的VOC排放清单,并探讨了森林源VOC在不同时空和不同龄级林分中的分配规律.结果表明,中国森林VOC总排放量为8 565.76 Gg,其中异戊二烯5 689.38 Gg(66.42%),单萜烯1 343.95 Gg(15.69%),其他VOC 1 532.43 Gg(17.89%);不同树种的VOC排放量差异较大,栎类、云杉、马尾松等为主要贡献树种,贡献率分别为45.22%、6.34%和5.22%;西南和东北地区为中国森林VOC主要排放区域,云南、四川、黑龙江、吉林、陕西5省排放最多,分别占全国总量的15.09%、12.58%、10.35%、7.49%和7.37%;森林VOC排放存在非常强的季节性变化,夏季排放量最大,占全年的56.66%;不同龄级林分对VOC排放的贡献有所不同,中龄林贡献最多,占森林排放总量的38.84%.