SeagrassNet monitoring across the Americas: case studies of seagrass decline

Seagrasses are an important coastal habitat worldwide and are indicative of environmental health at the critical land–sea interface. In many parts of the world, seagrasses are not well known, although they provide crucial functions and values to the world's oceans and to human populations dwelling along the coast. Established in 2001, SeagrassNet, a monitoring program for seagrasses worldwide, uses a standardized protocol for detecting change in seagrass habitat to capture both seagrass parameters and environmental variables. SeagrassNet is designed to statistically detect change over a relatively short time frame (1–2 years) through quarterly monitoring of permanent plots. Currently, SeagrassNet operates in 18 countries at 48 sites; at each site, a permanent transect is established and a team of people from the area collects data which is sent to the SeagrassNet database for analysis. We present five case studies based on SeagrassNet data from across the Americas (two sites in the USA, one in Belize, and two in Brazil) which have a common theme of seagrass decline; the study represents a first latitudinal comparison across a hemisphere using a common methodology. In two cases, rapid loss of seagrass was related to eutrophication, in two cases losses related to climate change, and in one case, the loss is attributed to a complex trophic interaction resulting from the presence of a marine protected area. SeagrassNet results provide documentation of seagrass change over time and allow us to make scientifically supported statements about the status of seagrass habitat and the extent of need for management action.     

长岛县旅游气候舒适度分析

气候舒适度是影响一个地区旅游资源开发和发展以及旅游季节游客数量的重要因素。利用长岛国家基本气象站1986—2015年的气温、降水、风速、相对湿度和日照时数等与旅游气候舒适度相关的气象观测资料,对山东省烟台市长岛县气候舒适度进行研究计算,划分出长岛适宜于旅游的季节分布;结合2011—2015年长岛县游客的月统计资料,分析研究长岛旅游气候舒适度与游客数量之间对应关系。结果表明:长岛县5—10月均较适宜旅游,其中最佳旅游时间段为6—9月,其他月份气候舒适度等级较低,基本不适合旅游。旅游游客数量与气候舒适度密切相关,综合气候舒适度指数每变化一个单位,长岛县游客数量月指数增加2.098个百分点。     

Modeling Study of the Effect of Anthropogenic Aerosols on Late Spring Drought in South China

In this study,the mechanisms underlying the decadal variability of late spring precipitation in South China are investigated by using the latest Community Earth System Model version 1 （CESM1）.We aim to unravel the effects of different climate forcing agents such as aerosols and greenhouse gases （GHGs） on the decadal variation of precipitation,based on transient experiments from pre-industry （for year 1850） to present-day （for year 2000）.Our results reveal that：（1） CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in South China; （2） only simulations including the forcing of anthropogenic aerosols can reproduce the observed decreasing trend of late spring precipitation from 1950-2000 in South China; （3） aerosols affect the decadal change of precipitation mainly by altering the large-scale atmospheric circulation,and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and （4） in comparison,other climate forcing agents such as GHGs have much smaller effects on the decadal change of spring precipitation in South China.     

新疆博州地区近46年来的气候变化特征

根据新疆博尔塔拉蒙古自治州(简称博州,下同)四个气象代表站点的气温及降水资料,利用线性趋势函数及t检验法分析了该地区近46年的气候变化。结果表明,博州年平均气温、平均最高气温、平均最低气温均呈上升趋势,而且平均最低气温上升的幅度远大于平均最高气温的上升幅度。年平均气温及年平均最低气温约在20世纪80年代中期出现了显著的均值突变,而年平均最高气温在80年代末出现突变;除春、夏季平均最高气温无明显变化趋势外,其它各季平均气温、平均最高气温、平均最低气温均呈上升趋势,其中均以冬季增幅最大,秋季次之;80年代冬夜升温最强劲,90年代则明显减弱;夏季的平均气温与平均最低气温均在70年代中期出现突变,比其它任何突变时间都早;暖温年多发生在80年代后,冷温年多发生在20世纪60年代、70年代。年降水量略呈上升趋势,少雨年多在60年代、70年代,多雨年多在近20年,除春季外,其余各季降水略有上升趋势。     

中国气候区划新方案

根据全国609个气象站1971-2000年的日气象观测资料,遵循地带性与非地带性相结合、发生同一性与区域气候特征相对一致性相结合、综合性和主导因素相结合、自下而上和自上而下相结合、空间分布连续性与取大去小等5个基本原则,在充分吸纳已有气候区划基本理论与区划方法的基础上,参照中国科学院《中国自然地理》编辑委员会制定的气候区划三级指标体系,对我国气候进行重新区划;结果将我国划分为12个温度带、24个干湿区、56个气候区。与先前区划方案相比发现:20世纪70年代以来,中国气候带、区的总体格局并未发生明显变化,但一些重要的气候分界线却出现了一定程度的移动。其中亚热带北界与暖温带北界均出现了北移,北方地区的半湿润与半干旱分界线也出现了不同程度的东移与南扩,同时中温带、暖温带、北亚热带和中亚热带的三级气候区也出现了一定程度的变动;这种变化可能主要是因为20世纪80年代以后我国大多数地区出现不同程度的增暖及北方一些区域出现干旱化而引起的;且与本区划所采用的资料站点和部分区划原则有一定更新有关。     

分辨率对区域气候极端事件模拟的影响

利用NCAR MM5V3对1999年6月长江流域的极端异常降水事件进行了模拟, 主要研究不同水平和垂直分辨率对极端区域气候事件模拟的影响.数值模拟试验表明:模式能够模拟出极端强降水的主要分布特征;水平分辨率的提高降低了模式模拟的强降水偏差,对逐日降水变化的模拟更加合理,而垂直分辨率的提高基本上也都减小了模拟的强降水过程的偏差,改善对强降水的模拟能力;模式水平、垂直分辨率的提高在一定程度上增强了对强降水过程的模拟能力.水平分辨率的提高能够改善模式对海平面气压的模拟,而垂直分辨率的提高可以改善模式模拟的地面气温和低层环流.分辨率对中层大气环流的影响不是很敏感.不同积云对流参数化方案模拟的对流降水比率随水平分辨率的变化是不同的,Grell方案对流降水比例随分辨率的提高而增加,而Kain-Fritsch方案的结果相反.     

Climate change mitigation scenarios and policies and measures: the case of Kazakhstan

This article illustrates the main difficulties encountered in the preparation of GHG emission projections and climate change mitigation policies and measures (P&M) for Kazakhstan. Difficulties in representing the system with an economic model have been overcome by representing the energy system with a technical-economic growth model (MARKAL-TIMES) based on the stock of existing plants, transformation processes, and end-use devices. GHG emission scenarios depend mainly on the pace of transition in Kazakhstan from a planned economy to a market economy. Three scenarios are portrayed: an incomplete transition, a fast and successful one, and even more advanced participation in global climate change mitigation, including participation in some emission trading schemes. If the transition to a market economy is completed by 2020, P&M already adopted may reduce emissions of CO₂ from combustion by about 85 MtCO₂ by 2030 – 17% of the emissions in the baseline (WOM) scenario. One-third of these reductions are likely to be obtained from the demand sectors, and two-thirds from the supply sectors. If every tonne of CO₂ not emitted is valued up to US$10 in 2020 and $20 in 2030, additional P&M may further reduce emissions by 110 MtCO₂ by 2030.     

Tankering strategies for evading emissions trading in aviation

Which actors in the aviation sector ought to be obliged to participate in emissions trading? The European Commission opted for the aircraft operator in their proposal for a Directive. A major drawback is that non-EU aircraft operators might legally challenge their inclusion in this scheme and, if the challenge was successful, discrimination between EU and non- EU operators would undermine the scheme. An alternative would be to place an obligation on fuel suppliers to prove possession of allowances, thus avoiding discrimination. However, emissions trading can be evaded to some extent by increased refuelling beyond EU boundaries (tankering). Typical city pairs were used to analyse the conditions under which such tankering strategies are economically attractive. The analysis shows that the attractiveness of tankering depends substantially on the relationship between fuel prices and allowance prices. If the price relation as of March 2006 is taken as a basis, tankering would be attractive within a radius of up to 4,000 km especially on southbound and eastward routes. Emissions trading could, under unfavourable conditions, be evaded for up to 20% of the total fuel consumption in aviation with the help of tankering. Although this value is only a theoretical upper limit, more than 10% of fuel consumption could be affected by tankering.     

Panta Rhei 2013–2015: global perspectives on hydrology,society and change

ABSTRACT

In 2013, the International Association of Hydrological Sciences (IAHS) launched the hydrological decade 2013–2022 with the theme “Panta Rhei: Change in Hydrology and Society”. The decade recognizes the urgency of hydrological research to understand and predict the interactions of society and water, to support sustainable water resource use under changing climatic and environmental conditions. This paper reports on the first Panta Rhei biennium 2013–2015, providing a comprehensive resource that describes the scope and direction of Panta Rhei. We bring together the knowledge of all the Panta Rhei working groups, to summarize the most pressing research questions and how the hydrological community is progressing towards those goals. We draw out interconnections between different strands of research, and reflect on the need to take a global view on hydrology in the current era of human impacts and environmental change. Finally, we look back to the six driving science questions identified at the outset of Panta Rhei, to quantify progress towards those aims.

Editor D. Koutsoyiannis; Associate editor not assigned     

中更新世转型时期南海北部上层水体结构演化特征——ODP1146站浮游有孔虫稳定同位素记录

文章以南海北部ODP1146站沉积物岩芯为研究材料,利用浮游有孔虫次表层水种Pulleniatina obliquiloculata壳体的氧、碳稳定同位素,结合该站位浮游及底栖有孔虫氧碳同位素数据,分析中更新世以来南海北部上层水体结构的演化。1.2 Ma以来ODP1146站P.obliquiloculata壳体δ^18O的变化可分3个阶段:1)1.2~0.9 Ma,冰期-间冰期变化幅度较小、主导周期为41 ka斜率周期;2)0.9~0.6 Ma,冰期旋回变化幅度逐渐增强、100 ka偏心率周期开始强化;3)0.6 Ma以来,冰期旋回呈现稳定且幅度较大的100 ka周期变化。0.9 Ma以来南海北部上层海水δ^18O的冰期旋回变幅增强,可能反映东亚冬季风在0.9 Ma之后显著强化。其中,表层水体δ^18O只在冰期变幅增强,P.obliquiloculata所反映的次表层水体δ^18O的变化幅度在冰期和间冰期都显著增强。约0.9 Ma浮游和底栖有孔虫δ^18O的100 ka周期几乎同时显现;但在0.9~0.6 Ma时期P.obliquiloculata的δ^18O偏心率周期更为显著、斜率周期的强度也更高。因此,冰期旋回周期转型及幅度变化两方面的证据共同反映温跃层结构演化在南海北部中更新世转型(MPT)气候转变过程中的特殊性。1.2 Ma以来ODP1146站P.obliquiloculata的δ^13C在0.02 Ma、0.49 Ma和0.99 Ma左右呈明显的碳重值,同时表层种-次表层种之间的δ^13C差值减小到近于0,可以解读为碳重值事件期间南海北部生产力相对减弱。