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We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory, on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth’s nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories. 相似文献
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《Geoforum》2016
We develop the outlines of a new approach to study the role of nonhumans in constituting ‘implementation’ and calculative–discursive practices in development projects and programs. Developing a framework around the concept of friction (material resistance or recalcitrance encountered in processes of transformation), we analyze an Energy Self-sufficient Village program in Indonesia. Focusing on specific projects and episodes within this program, we identify multiple distinctive instances of friction. These were driven by nonhumans’ (and humans’) resistance, as remolding of development beneficiaries’ practices was attempted by project administrators, government officials, entrepreneurs and by the (scientific) calculations embedded in their policies, strategies and models. In concluding, we distill four ways in which nonhumans relationally shape development practices: (a) by resisting representations and calculations produced by human actors, (b) by re-directing planned/expected courses of action, (c) through biophysical change to their weight or textures as they move in space and time, and (d) by mediating competition for resources. Overall, nonhumans play a central role in making and unmaking asymmetric relations of power in practice and by constituting practices that diverge from prior expectations, problematize linear understandings of ‘policy implementation’. Their material and discursive agency is multiple, manifesting differently in different relational settings, which highlights the importance of broadening the range of spokespersons who speak on behalf of nonhumans and whose voices can be considered reliable and true. Our study thus provides support to calls for pluralizing and democratizing development ‘expertise’ beyond the usual suspects in science, government and civil society. 相似文献
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Past research suggests that how we perceive risk can be related to how we attribute responsibility for risk-related issues, such as climate change; however, a gap in research lies in exploring possible connections between attribution of responsibility, risk perception, and information processing. Using the Risk Information Seeking and Processing model, this study fills this gap by examining how RISP-based variables are related to information processing and whether attribution of responsibility for mitigating climate change influences communication behaviors that are often predicted by elevated risk perceptions. Undergraduates at two large research universities (N = 572) were randomly assigned to read one of two newspaper articles that emphasized either individual responsibility (by highlighting personal actions) or societal responsibility (by highlighting government policy) for climate change mitigation. Results indicate that subjects in the individual responsibility condition were significantly more likely to process the message in a systematic manner; however, attribution of responsibility did not interact with risk perception to influence systematic processing. Moreover, attitudes toward climate change information and negative affect mediated the relationship between other key variables and systematic processing. These and other findings suggest that strategic communication about climate change may benefit from emphasizing individual responsibility to attract more attention from diverse audiences and to promote deeper thinking about the issue. Additional theoretical implications are presented. 相似文献
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Tropical Cyclone (TC) Dahlia occurred adjacent to over the equatorial southeastern Indian Ocean during the period 26 November – 3 December 2017 and was observed by the Bailong buoy, which provides in situ observations of high-frequency variations in the upper ocean environment. The diurnal sea surface temperature (dSST) variabilities during different stages of the passage of TC Dahlia are studied. The dSST variability is rather weak during the TC passing stage in contrast to the strong ranges before (0.35 °C) and after (0.57 °C) the TC. Before the influence of TC Dahlia, the dSST presented significant regular variability with a peak in the afternoon and minimum value in the morning, which is similar to the even larger range that occurred after TC Dahlia. During the passage of TC Dahlia, dSST decreased dramatically, and a uniform variation was presented due to the absence of strong heat fluxes and stirring and upwelling induced by strong winds. Further analysis through a one-dimensional mixed layer model (Price-Weller-Pinkel, PWP) indicated that the dominant elements responsible for the different dSST variations during distinct stages of TC Dahlia were shortwave radiation and surface wind, which strongly impacted the dSST evolution during TC Dahlia. The asymmetrical wind strength was responsible for the asymmetry of dSST variation. 相似文献
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基于全球土地利用类型和覆盖度,利用生长季多年平均（1982～2015年）归一化植被指数（Normalized Difference Vegetation Index,NDVI）和气候平均态（气温、降水量）数据,讨论了全球植被格局与气候因子之间的关系,建立了两者之间的多元回归模型,并分析了植被对气温和降水气候态敏感性的特征。植被与气候因子在气候梯度上存在明显的对应关系,回归模型可较好拟合气候态NDVI的全球分布格局,拟合与观测NDVI的相关系数达0.90。其中,常绿阔叶林、混交林、常绿针叶林、落叶阔叶林、农田和木本稀树草原空间分布的拟合能力较好（r>0.8）。不同土地覆盖类型的NDVI对气温、降水气候态的空间敏感性特征不同。整体而言,植被对气温和降水的敏感性呈现反相关关系（r=-0.6）。不同土地覆盖类型对气温表现出正/负敏感性,寒带灌木对气温的敏感性最强,而农作物、草原、裸地对气温负敏感性较大;植被对降水的敏感性均表现出正敏感性,其中落叶针叶林、草原和稀树草原对降水的空间敏感性较强。 相似文献
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Westerly Wind Events (WWEs) over the tropical Pacific are characterized by their spatiotemporal diversity and classified into six types based on their different locations and durations. Various types of WWEs exhibit quite different characteristics in terms of their amplitudes. The long events with a 10–30-day duration are stronger than the short events with a 6–10-day duration, and the maximum amplitudes of the Central-Pacific (C) type and Eastern-Pacific (E) type of long events are larger than the Western-Pacific (W) type of long ones. The evolutions of these six types of WWEs are also quite different. The W-type short and long events and the C-type long events show a distinct eastward propagation, whereas the C-type short events and the E-type short and long events have no apparent propagation direction. We demonstrate that such a difference in the eastward propagation of WWEs can be significantly associated with the Madden-Julian Oscillation (MJO). The W-type events are more influenced heavily by the MJO, as indicated by their more distinct eastward propagation patterns, than the two other types of WWEs. In addition to the MJO, the convectively coupled Kelvin waves are also associated with the WWEs, especially for the short events. 相似文献
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西太平洋副热带高压位置对华北盛夏降水的影响 总被引：5，自引：0，他引：5
应用1958～2002年NCEP/NCAR 500 hPa冉分析资料,分析夏季逐日西太平洋副热带高压在110°～130°E、20°～50°N区域脊线活动情况.发现盛夏(7～8月)副高在588 dagpm以上、脊线在30°N以北的日数与华北降水有大范围正相关区,中心相关系数0.561(显著性水平为0.001).分析发现西太平副热带高压越过30°N的初日(连续3天副高脊线越过30°N的首口)早晚与华北盛夏降水量显著相关,初口与华北盛夏的平均降水量相关系数为-0.385,即副高北上早华北盛夏降水多,反之副高北上晚华北盛夏降水少.110°～130°E区域副高脊线越过30°N的日数和初日能更好地描述西太平洋副高与华北乃至我国东部盛夏降水的关系,对实际业务工作具有重要意义. 相似文献
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冬春亚洲大气环流与华北中部夏季降水的相关分析 总被引：1，自引：0，他引：1
利用1957~2002年的NCEP/NCAR 500 hPa再分析资料以及同期华北地区夏季降水资料,分析了华北中部夏季降水与前期环流的关系。结果表明:夏季华北中部降水的多少与冬季东亚槽强弱、春季巴尔喀什湖到贝加尔湖的蒙古高原地区高度场呈显著相关。20世纪80年代中期以前冬季东亚槽偏强、春季蒙古高原地区高度值偏低;80年代中期之后冬季东亚槽开始转弱、春季蒙古高原地区高度值偏高。这与华北夏季降水的演变趋势相对应。说明冬季东亚槽的减弱以及春季蒙古高原地区高度值偏高是近年来华北夏季降水减少的原因之一。冬季东亚槽强对应夏季西太平洋副高在日本海地区高度呈偏强趋势,有利华北中部夏季降水偏多;春季蒙古高原地区高度值偏高有利于华北夏季出现西高东低形势,华北中部夏季降水易偏少。 相似文献
10.
《Journal of Atmospheric and Solar》2007,69(7):817-825
Measurements from the Global Positioning System (GPS) satellites provide a valuable source of information about the ionosphere in the form of ray-path integrations of electron density. Total electron content (TEC) through the ionosphere can be estimated for specific satellite-to-ground paths using the two GPS frequencies and knowledge of the dispersive properties of the ionosphere. One approach used is the ionospheric imaging tool Multi Instrument Data Analysis System (MIDAS), which uses differential phase data from a number of GPS satellites and receivers to create an ionospheric movie of electron density. This paper addresses the accuracy with which MIDAS images the electron density at the F-layer peak. Firstly, the image accuracy is tested using a simulation of the imaging technique, representative of 1 year of data. Experimental GPS phase data are then used to image the electron density during a period of disturbed geomagnetic activity during April 2002. The images are compared to independent measurements from three ionosondes located across Europe and confirm the underestimate in peak electron density that was found in the simulation. Regardless of the peak density errors the vertical TEC in the images remains accurate. The accuracy of the imaged peak electron density is shown to improve across the image when measurements from ionosondes are included in the inversion process. 相似文献