Emerging and Decaying Magnetic Flux and Subsurface Flows

We study the temporal variation of subsurface flows of 788 active regions and 978 quiet regions. The vertical-velocity component used in this study is derived from the divergence of the measured horizontal flows using mass conservation. The horizontal flows cover a range of depths from the surface to about 16 Mm and are determined by analyzing about five years of GONG high-resolution Doppler data with ring-diagram analysis. We determine the change in unsigned magnetic flux during the disk passage of each active region using MDI magnetograms binned to the ring-diagram grid. We then sort the data by their flux change from decaying to emerging flux and divide the data into five subsets of equal size. The average vertical flows of the emerging-flux subset are systematically shifted toward upflows compared to the grand average values of the complete data set, whereas the average flows of the decaying-flux subset show comparably more pronounced downflows especially near 8 Mm. For flux emergence, upflows become stronger with time with increasing flux at depths greater than about 10 Mm. At layers shallower than about 4 Mm, the flows might start to change from downflows to upflows, when flux emerges, and then back to downflows after the active regions are established. The flows in the layers between these two depth ranges show no response to the emerging flux. In the case of decaying flux, the flows change from strong upflows to downflows at depths greater than about 10 Mm, whereas the flows do not change systematically at other depths. A cross-correlation analysis shows that the flows in the near-surface and the deeper layers might change about one day before flux emerges. The flows associated with the quiet regions fluctuate with time but do not show any systematic variation.     

The INTEGRAL complete sample of type 1 AGN

In this paper we discuss the broad-band X-ray characteristics of a complete sample of 36 type 1 active galactic nuclei (AGN), detected by INTEGRAL in the 20–40 keV band above the 5.5σ level. We present, for all the objects in the sample, the broad-band (1–110 keV) spectral analysis obtained by using INTEGRAL / Swift /Burst Alert Telescope observations together with XMM–Newton , Chandra , ASCA and Swift /X-Ray Telescope data. We also present the general average properties of the sample, i.e. the distribution of photon indices, high-energy cut-offs, reflection fractions and absorption properties, together with an in-depth analysis of their parameter space. We find that the average Seyfert 1 power law has an index of 1.7 with a dispersion of 0.2. The mean cut-off energy is at around 100 keV, with most objects displaying E _c in the range 50–150 keV; the average amount of Compton reflection is 1.5 with a typical dispersion of 0.7. We do not find any convincing correlation between the various parameters, an indication that our analysis is not strongly dependent by the interplay between them. Finally, we investigate how the results presented in this work fit into current frameworks for AGN spectral modelling and cosmic diffuse X-ray background synthesis models.     

POLAR investigation of the Sun—POLARIS

The POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75° with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS’s primary objective: determining the relation between the magnetism and dynamics of the Sun’s polar regions and the solar cycle.

包含CO2因子的冠层光合作用简化模型及其关键参数数值敏感分析

利用美国Licor公司生产的Li-6200便携式光合作用测定仪对冬小麦叶片光合作用进行了较为系统的测定研究,在实测资料支持下建立了包含CO2因子的叶片和冠层光合作用模型,验证结果表明,模型具有较高准确性.利用模型对CO2影响参数μ进行数值敏感分析,结果表明:对叶片光合而言,μ=0.83时叶片光合作用模型拟合最好,随μ减小或增大,拟合精度均下降;对冠层光合而言,μ=0.83时模拟光合日总量达到最大值,μ减小或增大,光合日总量均下降.多因子数值分析表明:在辐射值较大的状况下,μ对冠层光合的影响更为显著.     

CO2地下埋存分布状况及环境影响的监测

 CO₂的地质埋存处理是减缓温室效应的现实选择之一。要保证埋存的有效性、安全性和持久性,需要对钻井（主要包括注入井和废弃井）、CO₂地下分布运移状况以及因CO₂渗漏所造成的环境影响等方面实施严格的监测管理。通过对以上各方面文献的查阅和综合分析,系统阐述了世界范围内目前CO₂地质埋存过程中所采用的各项主要监测技术。     

珠峰北坡绒布河谷大气二氧化碳浓度低值观测

In the summers of 2006 and 2007, the atmospheric CO2 concentration and the wind speed in the Rongbuk Valley on the northern slope of Mt. Everest were measured by an ultrasonic anemometer with an Li-7500 CO2/H2O gas analyzer. The average CO2 concentration was 370.23±0.59 and 367.45±1.91 ppm in June of 2006 and 2007, respectively. The values are much lower than those at sites with similar latitudes and altitudes worldwide. The observed atmospheric CO2 concentration in Rongbuk Valley can be affected by the transportation of prevailing down-valley winds from the up-valley direction to the observation site. Our results suggest that the Mt. Everest region could be ideal for background atmospheric and environmental studies.     

几种再分析地表气压资料在中国区域的适用性评估

应用台站观测资料对ERA-40, NCEP/NCAR以及NCEP/DOE再分析地表气压产品在中国不同区域、不同年代和不同季节的适用性进行了评估。分析发现, 几种再分析产品虽然能在一定程度上反映出观测资料所具有的时空分布特征, 但它们之间的差异却具有明显的区域和季节变化特征, 即冬季小而夏季大、东部地区小而西部地区大; 同时还发现ERA-40和NCEP/NCAR再分析产品在20世纪70年代以前均与观测资料有相对较大的差别, 特别是NCEP/NCAR在70年代以前的夏季气压值过于偏低, 从而夸大了很多地区的年代际变化特征。相比而言, ERA-40地表气压的长期变化趋势以及时空演变规律在中国大多数地区要优于NCEP/NCAR再分析产品, 特别是在中国西部地区。分析还表明, NCEP/DOE虽与观测资料存在一定的系统性偏差, 却与另外两种再分析产品有着较为相似的年际变化特征及趋势。     

世界主要CO2排放国家和地区的排放状况及对比分析

 通过对国际能源机构（IEA）最新公布的各国CO2排放量进行分析对比,结果显示,1990-2005年世界按购买力平价计算的CO2排放量整体呈下降趋势,降幅较大,而且在2000年之后基本保持稳定。经济合作与发展组织（OECD）国家按购买力平价计算的CO2排放量也有不同程度的减少,非OECD国家按购买力平价计算的CO2排放量与1990年相比整体上也呈现负增长,但各国情况相差较大。在人均排放量方面OECD国家普遍高于世界平均水平,而大多数非OECD国家则低于世界平均水平。     

Impact of Different Guidances on Sensitive Areas of Targeting Observations Based on the CNOP Method

The conditional nonlinear optimal perturbations(CNOPs) obtained by a fast algorithm are applied to determining the sensitive area for the targeting observation of Typhoon Matsa in 2005 using an operational regional prediction model-the Global/Regional Assimilation and PrEdiction System(GRAPES).Through a series of sensitivity experiments,several issues on targeting strategy design are discussed,including the effectivity of different guidances to determine the sensitive area(or targeting area) and the impa...