Assessing Weather Research and Forecasting (WRF) Model Parameterization Schemes Skill to Simulate Extreme Rainfall Events over Dar es Salaam on 21 December 2011

This paper evaluates the skills of physical Parameterization schemes in simulating extreme rainfall events over Dar es Salaam Region, Tanzania using the Weather Research and Forecasting (WRF) model. The model skill is determined during the 21 December 2011 flooding event. Ten sensitivity experiments have been conducted using Cumulus, Convective and Planetary boundary layer schemes to find the best combination and optimize the WRF model for the study area for heavy rainfall events. Model simulation results were verified against observed data using standard statistical tests. The model simulations show encouraging and better statistical results with the combination of Kain-Fritsch cumulus parameterization scheme, Lin microphysics scheme and Asymmetric Convection Model 2 (ACM2) planetary boundary scheme than any other combinations of physical parameterization schemes over Dar es Salaam region.

Greenland Ice Sheet Contribution to Future Global Sea Level Rise based on CMIP5 Models

Sea level rise （SLR） is one of the major socioeconomic risks associated with global warming. Mass losses from the Greenland ice sheet （GrIS） will be partially responsible for future SLR, although there are large uncertainties in modeled climate and ice sheet behavior. We used the ice sheet model SICOPOLIS （Simulation COde for POLythermal Ice Sheets） driven by climate projections from 20 models in the fifth phase of the Coupled Model Intercomparison Project （CMIP5） to estimate the GrlS contribution to global SLR. Based on the outputs of the 20 models, it is estimated that the GrIS will contribute 0-16 （0-27） cm to global SLR by 2100 under the Representative Concentration Pathways （RCP） 4.5 （RCP 8.5） scenarios. The projected SLR increases further to 7-22 （7-33） cm with 2~basal sliding included. In response to the results of the multimodel ensemble mean, the ice sheet model projects a global SLR of 3 cm and 7 cm （10 cm and 13 cm with 2~basal sliding） under the RCP 4.5 and RCP 8.5 scenarios, respectively. In addition, our results suggest that the uncertainty in future sea level projection caused by the large spread in climate projections could be reduced with model-evaluation and the selective use of model outputs.

Arctic Sea Ice and Eurasian Climate:A Review

The Arctic plays a fundamental role in the climate system and has shown significant climate change in recent decades,including the Arctic warming and decline of Arctic sea-ice extent and thickness. In contrast to the Arctic warming and reduction of Arctic sea ice, Europe, East Asia and North America have experienced anomalously cold conditions, with record snowfall during recent years. In this paper, we review current understanding of the sea-ice impacts on the Eurasian climate.Paleo, observational and modelling studies are covered to summarize several major themes, including： the variability of Arctic sea ice and its controls; the likely causes and apparent impacts of the Arctic sea-ice decline during the satellite era,as well as past and projected future impacts and trends; the links and feedback mechanisms between the Arctic sea ice and the Arctic Oscillation/North Atlantic Oscillation, the recent Eurasian cooling, winter atmospheric circulation, summer precipitation in East Asia, spring snowfall over Eurasia, East Asian winter monsoon, and midlatitude extreme weather; and the remote climate response（e.g., atmospheric circulation, air temperature） to changes in Arctic sea ice. We conclude with a brief summary and suggestions for future research.

Causes of Mid-Pliocene Strengthened Summer and Weakened Winter Monsoons over East Asia

The mid-Pliocene warm period was the most recent geological period in Earth＇s history that featured long-term warming. Both geological evidence and model results indicate that East Asian summer winds （EASWs） strengthened in monsoonal China, and that East Asian winter winds （EAWWs） weakened in northern monsoonal China during this period, as compared to the pre-industrial period. However, the corresponding mechanisms are still unclear. In this paper, the results of a set of numerical simulations are reported to analyze the effects of changed boundary conditions on the mid-Pliocene East Asian monsoon climate, based on PRISM3 （Pliocene Research Interpretation and Synoptic Mapping） palaeoenvironmental recon- struction. The model results showed that the combined changes of sea surface temperatures, atmospheric CO2 concentration, and ice sheet extent were necessary to generate an overall warm climate on a large scale, and that these factors exerted the greatest effects on the strengthening of EASWs in monsoonal China. The orographic change produced significant local warming and had the greatest effect on the weakening of EAWWs in northern monsoonal China in the mid-Pliocene. Thus, these two factors both had important but different effects on the monsoon change. In comparison, the effects of vegetational change on the strengthened EASWs and weakened EAWWs were relatively weak. The changed monsoon winds can be ex- plained by a reorganization of the meridional temperature gradient and zonal thermal contrast. Moreover, the effect of orbital parameters cannot be ignored. Results showed that changes in orbital parameters could have marked!y affected the EASWs and EAWWs, and caused significant short-term oscillations in the mid-Pliocene monsoon climate in East Asia.

Positive attitudes towards priority setting in clinical guidelines among Danish general practitioners: A web based survey

Aims: Increasing focus on improvement and optimisation of the treatment in primary care and reduction of healthcare costs emphasize the need to understand which factors determines adherence and non-adherence to clinical guidelines. In the present study, we examined attitudes towards clinical guidelines in Danish general practitioners (GPs). Methods: We conducted a survey among Danish GPs from all five regions of Denmark. In total, 443 GPs answered the web-based questionnaire that contained questions about attitudes and barriers to clinical guidelines. Results: More than 90% of the GPs reported that they have good knowledge of the guidelines and in general follows the guidelines. A majority of the GPs (81%) found it acceptable that economic considerations are part of the guidelines. The most important factors for non- adherence to guidelines were “need of adjustment to clinical practice” and “lack of confidence in guidelines”. The attitudes to clinical guidelines were not significantly associated with practice characteristics such as gender, years of experience, practice organisation and localisation. Conclusions: Our findings show that clinical guidelines are an integrated or internalised part of everyday practice among GPs in Denmark. Furthermore, the findings indicate that Danish GPs are positive towards applying priority setting in their practice. This is decisive in the light of rising healthcare costs due to development of new expensive technologies and ageing populations that puts pressure on the healthcare system in general and primary healthcare in particular.

Potential impacts of enhanced tropical cyclone activity on the El Ni?o–Southern Oscillation and East Asian monsoon in the mid-Piacenzian warm period

热带气旋不仅是一种严重的灾害性天气事件,其在气候时间尺度也可通过加强海洋上层垂直混合进而调节全球海洋经向热量输送。基于一个海气耦合模式,本文探讨了强热带气旋活动对皮亚琴察暖期(又称晚上新世暖期;约300万年前)ENSO和东亚季风环流的可能影响。模拟结果表明,热带气旋引起的海洋垂直混合加强可造成热带东太平洋显著增温、温跃层加深,但ENSO年际变率减弱。对东亚季风而言,夏季副热带高压南移且西伸,副热带急流减弱并南移,我国南方西南风加强;冬季东亚大槽加深,副热带急流南移,我国北方偏北风加强。上述模拟结果可增进我们对热带气旋气候反馈作用以及晚上新世暖期全球气候特征的认识。

Unprecedented Retreat in a 50-Year Observational Record for Petermann Glacier, North Greenland

Petermann Glacier is a marine-terminating outlet glacier that had a 70 km-long floating ice tongue prior to a～270 km2calving event that was observed from satellite sensors in August 2010,shortening the ice tongue by～27 km.Further,in July 2012,another 10 km was lost through calving.In order to understand these events in perspective,here the authors perform a long-term data analysis of Petermann Glacier calving-front variability and ice velocity for each year in the 1990s–2000s,supplemented by available observations from the previous three decades.Five major(on the order of 100 km2)calving events are identified,with～153 km2calved from1959 to 1961,～168 km2in 1991,～71 km2in 2001,～270 km2in 2010,and～130 km2in 2012—as well as～31km2calved in 2008.The increased frequency of major calving events in recent years has left the front terminus position retreated nearly 25 km beyond the range of observed in previous decades.In contrast,stable ice-dynamics are suggested from ice-velocity measurements made each year between 1993–2012,which are on average1063 m yr–1,with limited interannual variability and no significant trend;moreover,there is no apparent relationship between ice-velocity variability and calving events.The degree to which the massive calving events in 2010and 2012 represent natural episodic variability or a response to atmospheric and/or oceanic changes remains speculative;however,melt-induced weakening of the floating ice tongue in recent years is strongly suggested.

Mid-Pliocene Westerlies from Plio MIP Simulations

The midlatitude westerlies are one of the major components of the global atmospheric circulation. They play an important role in midlatitude weather and climate, and are particularly significant in interpreting aeolian sediments. In this study, we analyzed the behavior and the possible mechanism involved in the change of the westerlies, mainly in terms of the jet stream position, in the mid-Pliocene warm period （3.3 to 3.0 million years ago） using simulations of 15 climate models from the Pliocene Model Intercomparison Project （PlioMIP）. Compared to the reference period, the mid-Pliocene midlatitude westerlies generally shifted poleward （approximately 3.6° of latitude in the Northern Hemisphere and 1.9~ of latitude in the Southern Hemisphere at 850 hPa level） with a dipole pattern. The dipole pattern of the tropospheric zonal wind anomalies was closely related to the change of the tropospheric meridional temperature gradient as a result of thermal structure adjustment. The poleward shift of the midlatitude westerly jet corresponded to the poleward shift of the mean meridional circulation. The sea surface temperatures and sea ice may have affected the simulated temperature structure and zonal winds, causing the spread of the westerly anomalies in the mid-Pliocene between the atmosphere-only and coupled atmosphere-ocean general circulation model simulations.

Conditions for autonomous choice： a qualitative study of older adults＇ experience of decision-making in TAVR

耐心的自治是在为分享的决策的生物伦理学和一个基础的一个领先的原则。这研究为最近经历了 trans 导管的更老的成年人经验丰富的一种自治选择探索条件必要的大动脉的阀门代替(TAVR ).MethodsQualitative 学习一件有目的的样品的半结构化的会见十更旧(范围 73-89，中部 83.5 年) 在 TAVR 以后的成年人(中部 23 天) 。学习背景是在自从 2010，执行 TAVR 的一所大学医院的一个心脏的部门。当选择似乎难或不在时，分析由系统的文章 condensation.ResultsEven， TAVR 病人故意抓住了处理风险评价，矛盾心理和命运提供他们的机会。他们考虑了衰退比接受与过程有关的风险更坏的治疗。被他们的医生彻底地劝告的经验形成了自治信任的基础。他们为医生建议感到了的信任关于过程和风险减轻了矛盾心理。TAVR 病人表示了与 self-empowerment 一致的感情并且宣称它不得不是他们的决定。甚至这样，选择干预为一项义务到他们的家庭或消极地相信它也是一个自治决定的 reported.ConclusionsOlder TAVR 病人经验可以包含坦率的折衷；象一个有弹性的自我看法一样商讨医生相关性。医生们应该特别知道 how older 成年人微妙的认知衰落和倾向到当获得知情同意时，保存他们能影响他们的医药决策的身份。心脏病专家和另外的供应商可以也使用这些卓见开发更好对如此的固有的复杂性作出回应的新策略。

Strengthened African Summer Monsoon in the Mid-Piacenzian

Using model results from the first phase of the Pliocene Model Intercomparison Project （PlioMIP） and four experiments with CAM4, the intensified African summer monsoon （ASM） in the mid-Piacenzian and corresponding mechanisms are analyzed. The results from PlioMIP show that the ASM intensified and summer precipitation increased in North Africa during the mid-Piacenzian, which can be explained by the increased net energy in the atmospheric column above North Africa. Further experiments with CAM4 indicated that the combined changes in the mid-Piacenzian of atmospheric CO2 concentration and SST, as well as the vegetation change, could have substantially increased the net energy in the atmospheric column over North Africa and further intensified the ASM. The experiments also demonstrated that topography change had a weak effect. Overall, the combined changes of atmospheric CO2 concentration and SST were the most important factor that brought about the intensified ASM in the mid-Piacenzian.

Seismic analysis of aircraft accidents

Seismic records from Finnish and Swedish stations were analyzed for a study of two aircraft accidents in Finland and Sweden. A Hornet F-18 fighter crashed in central Finland, and analysis of recorded impact signals from 7 nearby seismic stations yielded in a crash location only 4 km in error. An estimated magnitude (ML) of 0.5 units gave an impact velocity of 335 m/sec (1200 km/h), which was in excellent agreement with that reported by the Finnish Air Force. A Norwegian Hercules transport plane crashed in foul weather near the summit of Mt. Kebnekaise, NW Sweden. Both seismic and infrasound signals were weak, and in our interpretation, this implied that the Hercules aircraft had a less steep impact angle against the mountain. We also examined seismic analyses of other spectacular air accidents like that of Lockerbie, UK in 1988, and terrorist aircraft attacks on September 11th, 2001 in the USA. Likewise, accidents at sea, such as the sinking of the Russian submarine Kursk in the Barents sea in 2000, and the freighter M/S Rocknes near Bergen in 2004, were recorded and analyzed seismically. In this study, we demonstrated that it was feasible to use seismic registrations to locate impact sites, and to define the exact time of such accidents. Also, negative evidence, i.e., lack of seismic recordings, may provide some information of such accidents and their consequences.

过去千年北大西洋热带气旋生成潜势的模拟研究：基于PMIP3气候模式

本文利用古气候模式比较计划第三阶段（PMIP3）10个耦合模式结果研究了过去千年北大西洋热带气旋生成潜势的空间特征。对于影响热带气旋生成的大尺度环境场而言，模拟结果表明中世纪暖期（950～1200A．D．）热带气旋潜在强度相对于小冰期（1600～1850A．D．）在北大西洋普遍增强，尤其是中纬度地区。中世纪暖期垂直风切变在10°～30°N之间的纬度带显著减小，而对流层中层相对湿度和低层绝对涡度在北大西洋东部增大。基于热带气旋生成潜势指数，中世纪暖期大尺度环境条件有利于热带气旋在北大西洋的生成和发展。同时，中世纪暖期热带气旋高空引导气流为东风异常，有利于热带气旋登陆北美地区。在百年尺度热带气旋气候态的角度，模拟结果与地质证据基本一致。此外，敏感性试验结果表明太阳辐射增加和火山活动减少对中世纪暖期北大西洋热带气旋生成潜势增加均有作用。

上新世中期格陵兰冰盖模拟

格陵兰冰盖是造成21世纪海平面预估不确定性的一个主要来源,而研究格陵兰冰盖对过去暖期气候的响应,可以为研究未来格陵兰冰盖提供参考.本文采用全球气候模式CAM 3.1(Community Atmosphere Model version 3.1),CAM 4和NorESM(Norwegian Earth System Model)以及冰盖模式SICOPOLIS(SImulation COde for POLythermal Ice Sheets),对上新世中期暖期(距今～3 Ma)格陵兰气候和冰盖展开模拟研究.模拟结果表明上新世中期格陵兰夏季平均气温比工业革命前高9.4～13.4℃,年平均降水增加了65.2～108.3 mm a 1.在上新世中期暖湿的气候背景下,仅有少量冰存在于格陵兰东部沿岸高海拔地区;与参照试验相比,上新世中期格陵兰冰盖减少造成全球海平面比现代高大约7.8～8.1 m.同时,古气候代用资料也表明上新世中期格陵兰可能无大规模冰盖存在.

上新世海道变化对中国气候的影响

气候记录显示晚新生代全球气候在上新世3～4Ma发生明显变化，这一转变弓海道变化触发的全球变冷密切相关。对于这一时期，以往数值模拟研究较多关注热带海道（中美海道和印尼海道），而白令海峡打开的气候效应往往被忽略。本文利用挪威地球系统模式，模拟了白令海峡打开和热带海道关闭/收缩对中国气候的影响。白令海峡和热带海道的变化，都可以引起全球大部分地区的气候响应；但白令海峡打开的气候影响主要集中在中高纬地区，对热带气候的影响并不显著；而热带海道的变化呵以引起全球大范围地区的温度降低，导致热带太平洋表面温度升高，使得热带太平洋东西之间的温度梯度加强，热带太平洋厄尔尼诺一南方涛动年代际变率加强。对于上新龇中国区域气候而言，热带海道的变化比白令海峡打开的作用更加重要，热带海道关闭／收缩可以引起我国东北和西南地区的气候响应，而白令海峡打开对我国气候的影响几乎可以忽略。

青藏高原主体与周边区域隆升对亚洲季风气候的影响

本文利用全球海气耦合模式，设计并进行了7组高原不同隆升情景的数值试验，集中研究了青藏高原隆升在欧亚内陆干旱演化中的作用。在无高原试验中，亚洲副热带干旱区为东西对称的纬向型分布；随着高原高度的增加，一方面有助于东亚季风降水的向北扩展，另一方面导致欧亚大陆西风强度显著减弱，使得亚洲副热带气候纬向不对称性增加，同时欧亚中纬度干旱面积增加。其原因是，高原隆升导致近地层气温下降，进而大气含水量减小；同时，地形的阻挡效应导致纬向和经向的环流减弱，这两个因素综合导致内陆地区水汽输送的减弱是中亚干旱区范围增加的主要动力学机制。与以往大气模式试验一致，海气耦合试验支持了高原隆升是亚洲内陆水汽输送和降水减少，以及内陆干旱化加剧的重要原因的科学认识。

第四纪北半球冰盖发育与东亚气候的遥相关

新生代东亚气候演化和北半球冰盖演化具有很好的耦合性。这种耦合性在气候学上可以被称为遥相关。一般认为，北半球冰盖的消长通过影响西伯利亚高压来改变东亚气候。第四纪冰期，北半球冰盖的增长，可以加强西伯利亚高压，从而增强东亚冬季风和加剧亚洲内陆干旱程度；反之，间冰期北半球冰盖的消退，可以减弱西伯利亚高压，并加强东亚夏季风。本文利用通用大气模式CAM4，开展理想试验，模拟了北半球冰盖对东亚气候的影响。模拟结果证实，冰期北半球冰盖消长与东亚地区气候变化存在遥相关，很好地支持了地质记录所反映的东亚气候与冰盖演化之间的耦合性。第四纪冰期，北半球气候变冷和冰盖发育，可以加剧我国北方的干旱程度。北半球北美-欧亚冰盖的发育，尤其是冬季，通过影响北半球的槽脊系统，在北美-欧亚冰盖南侧形成一个气旋式环流异常，这对加强我国西北内陆和黄土高原区西风或西北风至关重要。然而我们的模拟并不支持北美-欧亚冰盖通过加强西伯利亚高压来影响东亚冬季大气环流这一传统认识，第四纪北半球冰盖发育与东亚气候的遥相关可能比我们原有的认识复杂。

两个气候模式对我国MIS 5e气候的模拟研究

理解历史时期气候变化的现象和机制,对预测未来气候变化有重要的启示意义。过去多个间冰期中,末次间冰期最暖期(MIS 5e)被认为是研究未来气候变化的典型时期。我们利用NorESM-L和CESM两个气候模式对MIS 5e开展数值模拟研究。模拟结果揭示,由地球轨道参数导致的太阳辐射变化是造成MIS 5e温暖气候的主导因素。在我国,与工业革命前相比,MIS 5e年平均地表温度降低、夏季升高、冬季降低;年降水量和夏季降水量在中部地区减少、其他地区增加,冬季降水量一致减少。与地质记录重建的年平均结果相比,模拟结果整体上比代用资料重建偏冷、偏干。这种模拟与地质记录重建之间的差异可能由以下因素导致:地球系统模式的模拟方案存在简化、古气候代用指标的气候意义存在多解性、模拟的地表温度和降水与代用指标重建结果之间的对比存在不确定性。如何减小模拟与重建记录对比的差异,这仍需在今后的研究中不断探索。