Uncertainties in gas exchange parameterization during the SAGE dual-tracer experiment

A dual tracer experiment was carried out during the SAGE experiment using the inert tracers SF₆ and ³He, in order to determine the gas transfer velocity, k, at high wind speeds in the Southern Ocean. Wind speed/gas exchange parameterization is characterised by significant variability and we examine the major measurement uncertainties that contribute to that scatter. Correction for the airflow distortion over the research vessel, as determined by computational fluid dynamics (CFD) modelling, had the effect of increasing the calculated value of k by 30%. On the short time scales of such experiments, the spatial variability of the wind field resulted in differences between ship and satellite QuikSCAT winds, which produced significant differences in transfer velocity. With such variability between wind estimates, the comparison between gas exchange parameterizations from diverse experiments should clearly be made on the basis of the same wind product. Uncertainty in mixed layer depth of ∼10% arose from mixed layer deepening at high wind speed and limited resolution of vertical sampling. However the assumption of equal mixing of the two tracers is borne out by the experiment. Two dual tracer releases were carried out during SAGE, and showed no significant difference in transfer velocities using QuikSCAT winds, despite the differences in wind history. In the SAGE experiment, duration limitation on the development of waves was shown to be an important factor for Southern Ocean waves, despite the presence of long fetches.     

Measuring Earth orientation with the global positioning system

Summary A globally distributed network of high-precision receivers which obtain data from the full Global Positioning System (GPS) configuration of 18 or more satellites may soon become an efficient and economical method for the rapid determination of short-term variations in Earth orientation. A covariance analysis has been performed to evaluate the errors associated with GPS monitoring of Earth orientation. Earth orientation parameters were modeled either as constants over observing windows of various lengths, or as stochastic process-noise variables. The sensitivity of Earth orientation estimates to systematic errors in selected model parameters was also examined. GPS measurements appear to be highly competitive with those from other techniques, and have the potential to generate nearly continuous centimeter-level Earth orientation information to aid both spacecraft navigation and the study of high-frequency Earth orientation-related processes.     

变形模型可区分度量

在监测网设计阶段，变形体的变形特性一般不是完全清楚。因此，设计的监测方案应当能有效地和足够灵敏地区分几种可能的模型。本文研究了模型的可区分度量，所用的方法具有思路明确、清晰等特点，特别适用于在设计阶段设置指标。文中通过一个模拟网的分析和讨论，说明采用模型可区分度量作为设计准则的必要性。分析的结果还和Forstner法所得的结果进行初步的比较。     

Forecasting the Ethiopian Coffee Price Using Kalman Filtering Algorithm

Ethiopian coffee price is highly fluctuated and has significant effect on the economy of the country. Conducting a research on forecasting coffee price has theoretical and practical importance.This study aims at forecasting the coffee price in Ethiopia. We used daily closed price data of Ethiopian coffee recorded in the period 25 June 2008 to 5 January 2017 obtained from Ethiopia commodity exchange (ECX) market to analyse coffee prices fluctuation. Here, the nature of coffee price is non-stationary and we apply the Kalman filtering algorithm on a single linear state space model to estimate and forecast an optimal value of coffee price. The performance of the algorithm for estimating and forecasting the coffee price is evaluated by using root mean square error (RMSE). Based on the linear state space model and the Kalman filtering algorithm, the root mean square error (RMSE) is 0.000016375, which is small enough, and it indicates that the algorithm performs well.     

用卡尔曼滤波算法预测埃塞俄比亚咖啡价格（英文）

埃塞俄比亚咖啡价格波动很大,因此对国家经济发展的影响不容小视,对咖啡价格进行预测具有理论和实践意义。为了分析咖啡价格波动,我们采用来自埃塞俄比亚商品交易所(ECX)记录的2008年6月25日至2017年1月5日期间咖啡日收盘价数据。在这里,咖啡价格的性质是非平稳的,我们在单个线性状态空间模型上应用卡尔曼滤波算法来预测咖啡价格的最优值,主要通过使用均方根误差(RMSE)来评估用于预测咖啡价格的算法的性能。基于线性状态空间模型和卡尔曼滤波算法,均方根误差(RMSE)为0.000016375,说明该算法性能良好,研究结果可靠。     

On the Need for Economic Assessment of Natural Capital (A Case Study of Tomsk Oblast)

This article presents the rationale for the need to take into account and assess natural capital as an important factor for viable managerial decision-making concerning the study, use and reproduction of natural resources in the interests of sustainable development. The activity of authorities in Tomsk oblast was used as an example in examining the issues related to integration of accounting and assessing natural capital and ecosystem services in the system of managerial decision-making. We used strategic and normative documents of Tomsk oblast, departmental information and material from previous research into assessments of natural capital. A rationale is given for the need to improve the institutional conditions for proper inventory and assessment of all functions of natural capital and ecosystems in managerial decision-making, namely the development of the monitoring system for economic value in the sphere of environmental management which is based on the system of ecological-economic accounting and constitutes a set of coherent statistical indicators reflecting the status of natural capital. The mechanism is suggested for generation of the information-methodological base of economic assessment of natural capital. It is determined that a qualitatively new information basis integrated into the system of regional management. Qualitatively new information basis integrated into the regional government system will make it possible not to simply obtain information on the flows of expenditures and benefits in the sphere of environmental management but also to ensure interaction between state and municipal authorities and with organizations and the population. The monitoring system for economic value of natural capital and ecosystem services integrated into the region’s executive bodies will permit adaptive governance of environmental management of the region in the face of changes and uncertainty.     

Transitions to Energy and Climate Security in Southeast Asia? Civil Society Encounters with Illiberalism in Thailand and Myanmar

ABSTRACT

All states, whether governed by liberal or illiberal regimes, face the prospect of momentous and potentially catastrophic environmental impacts due to climate change. Historically, energy policy has been directed towards simply achieving energy security. This goal has now been significantly complicated by the need to achieve it while minimizing greenhouse gas emissions. Environmental non governmental organizations (ENGOs) could play a crucial role in promoting the transition to energy and climate security but the relative (il)liberalism of the political regime they operate under influences their effectiveness. This article assesses how ENGOs have impacted on the transition to energy and climate security in Myanmar and Thailand, two Southeast Asian countries highly susceptible to climate impacts and characterized by illiberal rule. It finds that the impact of ENGOs was highly dependent on their strategies, tactics and operation, with community-level projects providing a key route to effect change under conditions of extreme illiberalism.     

Functional attributes of epilithic diatoms for palaeoenvironmental interpretations in South-West Greenland lakes

Benthic diatoms are commonly used for palaeoenvironmental reconstruction in Arctic regions, but interpretation of their ecology remains challenging. We studied epilithic diatom assemblages from the shallow margins of 19 lakes from three areas (coast-inland-ice sheet margin) along a climate gradient in Kangerlussuaq, West Greenland during two periods; shortly after ice-off (spring) and in the middle of the growth season (summer). We aimed to understand the distribution of Arctic epilithic diatoms in relation to water chemistry gradients during the two seasons, to investigate their incorporation into lake sediments and to assess their applicability as palaeoenvironmental indicators. Diatoms were correlated with nutrients in the spring and alkalinity/major ions in the summer, when nutrients were depleted; approximately half of the variance explained was independent of spatial factors. When categorised by functional attributes, diatom seasonal succession differed among regions with the most obvious changes in inland lakes where summer temperatures are warmer, organic nutrient processing is prevalent and silicate is limiting. These conditions led to small, motile and adnate diatoms being abundant in inland lakes during the summer (Nitzschia spp., Encyonopsis microcephala), as these functional attributes are suited to living within complex mats of non-siliceous microbial biofilms. Seasonal succession in silica-rich lakes at the coast was less pronounced and assemblages included Tabellaria flocculosa (indicating more acidic conditions) and Hannaea arcus (indicating input from inflowing rivers). The nitrogen-fixing diatom Epithemia sorex increased from the coast to the ice sheet, negatively correlating with a gradient of reactive nitrogen. The presence of this diatom in Holocene sediment records alongside cyanobacterial carotenoids during arid periods of low nitrogen delivery, suggests that it is a useful indicator of nitrogen limitation. Nitzschia species appear to be associated with high concentrations of organic carbon and heterotrophy, but their poor representation in West Greenland lake sediments due to taphonomic processes limits their palaeoenvironmental application in this region. Proportions of epilithic taxa in lake sediment records of coastal lakes increased during some wetter periods of the Holocene, suggesting that snowpack-derived nutrient delivery may offer diatom taxa living at lake margins a competitive advantage over planktonic diatoms during the “moating” ice melt period. Thus, further research investigating linkages between epilithic diatoms, snowpack and nutrient delivery in seasonally frozen lakes is recommended as these taxa live on the ‘front-line’ during the spring and may be especially sensitive to changes in snowmelt conditions.