Abstract. Volcanic eruptions have a significant impact on global temperature; their consequences are of particular interest in regions that are especially sensitive to climate change, like the Tibetan Plateau. In this study, we develop a temperature-sensitive tree-ring-width standard chronology covering the period 1348–2014 CE using Qilian juniper (Sabina przewalskii (Kom.)) samples collected from the Animaqin Mountains on the Tibetan Plateau. We reconstruct the annual (prior August to current July) mean minimum temperature (Tmin) since 1380 CE and show that our reconstruction explains 58 % of the variance during the 1960–2014 calibration period. Our results demonstrate that in 77.8 % of cases in which a volcanic eruption with a Volcanic Explosivity Index of 5 or greater occurs, temperature decreases in the year of or the year following the eruption. The results of the superposed epoch analysis also indicate that there is a high probability that the Tmin decreases for 2 years after a large volcanic eruption, especially when such eruptions occur in the Northern Hemisphere.
Barrier coverage is a fundamental issue in wireless sensor networks (WSNs). Most existing works have developed centralized algorithms and applied the Boolean Sensing Model (BSM). However, the critical characteristics of sensors and environmental conditions have been neglected, which leads to the problem that the developed mechanisms are not practical, and their performance shows a large difference in real applications. On the other hand, the centralized algorithms also lack scalability and flexibility when the topologies of WSNs are dynamically changed. Based on the Elfes Sensing Model (ESM), this paper proposes a distributed Joint Surveillance Quality and Energy Conservation mechanism (JSQE), which aims to satisfy the requirements of the desired surveillance quality and minimize the number of working sensors. The proposed JSQE first evaluates the sensing probability of each sensor and identifies the location of the weakest surveillance quality. Then, the JSQE further schedules the sensor with the maximum contribution to the bottleneck location to improve the overall surveillance quality. Extensive experiment results show that our proposed JSQE outperforms the existing studies in terms of surveillance quality, the number of working sensors, and the efficiency and fairness of surveillance quality. In particular, the JSQE improves the surveillance quality by 15% and reduces the number of awake sensors by 22% compared with the relevant TOBA.
Based on the tree-ring increment cores of Pinus tabuliformis collected from the eastern Yinshan Mountains, the tree-ring width chronology was developed. The correlation coefficients were calculated between the chronology and monthly mean temperature and monthly precipitation during the instrumental period of AD 1952-2007. The results showed that the highest correlation was found between the total precipitation from September of previous year to June of current year and the chronology (r=0.73, n=56, P<0.01). Based on the correlation, the September of previous year to June of current year total precipitation variation was reconstructed in the eastern Yin-shan Mountains during the past 399 years (AD 1619-2017). The reconstruction explained 54.9% of the variation in the total precipitation from September of previous year to June of current year for the calibration period (AD 1952-2007). Both the 'leave-one-out' cross validation and split-period validation showed that the model was relatively robust, with sufficient skills of estimation and high reliability. At the decadal scale, there were four wet periods (AD 1619-1663, AD 1705-1711, AD 1945-1963, and AD 1979-2017)) and four dry periods (AD 1734-1767, AD 1786-1814, AD 1839-1867, and AD 1888-1942) in the past 399 years. Among those periods, the AD 1979-2017 was the wettest period, and AD 1888-1942 was the longest dry duration with the driest period at the late 1920s. Results of power spectral analysis revealed cyclic fluctuations of precipitation series on 2-7 years and 125 years. In addition, the comparison with other reconstructions and spatial correlation analysis indicated that the reconstructed precipitation series well represented regional scale precipitation variation.基于阴山东部油松树轮样芯,建立采样区域树轮宽度年表,并计算器测时期(AD 1952—2007)月均温和月降水量与树轮宽度年表的相关系数。结果表明: 树轮宽度年表与上一年9月至当年6月降水量变化的相关性最高(r=0.73,n=56,P<0.01),基于此重建了阴山东部过去399年(AD 1619—2017)上一年9月至当年6月的降水量变化历史。该重建解释了器测时期上一年9月至当年6月降水量54.9%的方差,经“留一法”交叉验证和分段独立检验证明,重建方程稳定可靠。在年代际尺度上,过去399年存在4个湿润时期(AD 1619—1663、AD 1705—1711、AD 1945—1963和AD 1979—2017)和4个干旱时期(AD 1734—1767、AD 1786—1814、AD 1839—1867和AD 1888—1942)。其中,AD 1979—2017是最湿润的时期,而AD 1888—1942是干旱持续最长的时段,包含最干旱时期1920s晚期。功率谱分析显示,过去399年该区降水具有2～7年和125年准周期变化。通过与邻近区域重建对比及空间相关分析表明,本降水重建序列可以较好地代表研究区域的降水变化。.
Three tree-ring STD chronologies of Abies faxoniana were developed from Songpan region Sichuan Province, and a regional chronology(RC) was established based on the three STD chronologies. The calculation shows that the tree-ring width was significantly correlated with temperature, and the RC had the highest correlation( r =0.576, P R adj2=32%, N =59, F =28.33). In the past 310 years, there were 8 warm periods and 7 cool periods. According to analysis of temporal and spatial correlation, it indicated that the reconstructed series with good spatial and temporal representation. Our reconstruction was validated by other tree-ring based temperature reconstructions from the surrounding area, glacier advances and retreats, and the documented climate disaster events. MTM analysis shows that there exist periods of 2-3 a, 26 a, quasi-33 a and quasi-40 a cycles.
This study presents a 304-year mean July-October maximum temperature reconstruction for the southeastern Tibetan Plateau based on both tree-ring width and maximum latewood density data. The reconstruction explained 58% of the variance in July-October maximum temperature during the calibration period (1958-2005). On the decadal scale, we identified two prominent cold periods during AD 1801-1833 and 1961-2003 and two prominent warm periods during AD 1730-1800 and 1928-1960, which are consistent with other reconstructions from the nearby region. Based on the reconstructed temperature series and volcanic eruption chronology, we found that most extreme cold years were in good agreement with major volcanic eruptions, such as 1816 after the Tambora eruption in 1815. Also, clusters of volcanic eruptions probably made the 1810s the coldest decade in the past 300 years. Our results indicated that fingerprints of major volcanic eruptions can be found in the reconstructed temperature records, while the responses of regional climate to these eruption events varied in space and time in the southeastern Tibetan Plateau.
Tuyuhun and Tubo were two important states that thrived in north-western China during AD 311-900 in parallel with the Han Chinese dynasties of Sui and Tang periods. The Reshui Tomb Cluster located in Dulan County of the north-eastern Tibetan Plateau is an important cultural relic of the Tuyuhun-Tubo age. The official excavations of the Reshui tombs were regarded as top events in archaeology in the 1980s and 1990s in China. The Reshui-1 Tomb is the largest one among the tombs in the area. Since its excavation, there have been debates on whether the owner of the tomb belonged to the Tuyuhun or Tubo ethnicity. Therefore, accurately dating the Reshui-1 Tomb has a critical place in studying the Tubo and Tuyuhun histories. We collected 7 discs and 11 increment cores of Qilian juniper (Juniperus przewalskii Kom.) from the exposed and fallen beams of the roof of the Reshui-1Tomb. The lengths of the 16 tree-ring records are between 69 and 152 years. Based on a previously developed master dating chronology using Qilian juniper samples from the eastern Qaidam Basin, the calendar dates of the 16 specimens were determined by the COFE-CHA program and visual dating procedure. The average inter-series correlation among the dated sample series is 0.696, indicating good quality of cross-dating. The year of the outermost rings is AD 715 for the 7 discs and 4 out of the 9 increment cores. Moreover, the ring-width variations of the samples are consistent with the existing chronologies from the region. The presence of late-wood of AD 715 in the samples indicated that the Reshui-1 Tomb was completed in late AD 715 or early 716, which means that the Reshui-1 Tomb was finished in the Tubo age. This date provides direct evidence for archaeologists to determine the owner's ethnicity and identify of the Reshui-1 Tomb.
Disease bio-banks are an important strategic resource for medicine development. Such a bank with complete information and high information sharing enhances the competitiveness of medicine and promote the development of translational medicine. The present development of such banks is found with such setbacks as weak government leadership and standardization, as well as lack of a sharing mechanism. Therefore medical institutions should strengthen their standardization and informationization of disease bio-banks, which deserve sufficient government policy support and guidance. These efforts will help preserve our rich clinical resources, in addition to their integration and sharing for medicine advancement.
Key words:
Disease bio-bank; Translational medicine; Standardization; Informationization; Resource sharing
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