三峡水库156m蓄水前后澎溪河回水区藻类多样性变化特征

为了解156 m蓄水前后三峡水库次级河流藻类多样性变化特征,对2007年7月至2008年1月澎溪河回水区的藻类种群结构的变化进行连续监测.基于三峡水库水位调度特点,将监测期划分为蓄水前、中、后三个时段,即7-9月、10月、11月至翌年1月,应用Shannon-Weaver多样性指数H’对藻类多样性进行评价,通过Connell中度扰动假说理论结合优势藻种探讨蓄水过程水动力变化及藻类多样性的变化特征.结果表明:2007年7-9月蓄水前H’均值为3.466±0.317,10月蓄水期则降为3.246±0.338,而11月蓄水后高水位阶段H’均值上升为3.431±0.352.蓄水前澎溪河回水区具有河流型特征,流量与降雨作为主要的物理扰动因子影响水体扰动强度,进而引起多样性变化.10月蓄水期间水位突升、流量骤降导致水体扰动强度加剧,较蓄水前藻类多样性下降.自11月蓄水后的高水位阶段,降雨较小、流量趋于稳定,水体扰动降低,多样性回升并维持在相对稳定的状态.     

永年地震台水管倾斜仪降水干扰异常判定

针对河北永年地震台水管仪2016年7月21日EW分量快速西倾、NS分量快速北倾的异常现象,进行现场详细调查及排查,发现受7月19日—20日强降雨影响,台站西北方向出现有限范围的雨水汇集区,造成该区域荷载发生迅速变化,利用荷载模型进行定量计算,进一步分析该影响因素对观测结果的影响。     

APOD mission status and preliminary results

On September 20 th, 2015, twenty satellites were successfully deployed into a near-polar circular orbit at 520 km altitude by the Chinese CZ-6 test rocket, which was launched from the Tai Yuan Satellite Launch Center. Among these satellites, a set of 4 Cube Sats conform the atmospheric density detection and precise orbit determination(APOD) mission, which is projected for atmospheric density estimation from in-situ detection and precise orbit products. The APOD satellites are manufactured by China Spacesat Co. Ltd. and the payload instruments include an atmospheric density detector(ADD), a dual-frequency dualmode global navigation satellite system(GNSS) receiver(GPS and Beidou), a satellite laser ranging(SLR) reflector, and an S/Xband very long baseline interferometry(VLBI) beacon. In this paper, we compare the GNSS precise orbit products with colocated SLR observations, and the 3 D orbit accuracy shows better than 10 cm RMS. These results reveal the great potential of the onboard micro-electro-mechanical system(MEMS) GNSS receiver. After calibrating ADD density estimates with precise orbit products, the accuracy of our density products can reach about 10% with respect to the background density. Density estimates from APOD are of a great importance for scientific studies on upper atmosphere variations and useful for model data assimilation.     

Characteristics of low altitude ionospheric electric field over Hainan Island,China

A sounding rocket experiment undertaken by the Chinese Meridian Project from a low latitude station on Hainan Island(19.5°N,109.1°E),China,measured the DC electric field during 05:45-05:52 LT on April 5,2013.The data observed using a set of electric field double probes,as part of the rocket's scientific payload,revealed the special profile of how the vectors of the DC electric field vary with altitude between 130 and 190 km.During the experiment,the vertical electric field was downward,and the maximum vertical electric field was nearly 5.1 mV/m near the altitude of 176 km.The zonal electric field was eastward and slightly less than 0.6 mV/m.The plasma drift velocity was estimated from the E×B motion,and the zonal drift velocity was eastward and of the order of 100 m/s.The zonal wind velocity was also estimated using the drift velocity near the maximum density height in the F1-region,and it was found to be nearly 120 m/s.This work constituted the first in situ measurement of the DC electric field conducted within the Fl-region(between 130 and 190 km) in the East Asian Sector.     

大地电磁相位超象限现象的各向异性模型研究——以上下结构为例

大地电磁观测数据中的相位超象限现象可以由不同的电性结构产生.本文在已实现大地电磁三维任意各向异性有限差分正演的基础上,以具有上下结构关系的三维各向异性模型为例,分析各向异性体的规模以及参数变化对阻抗相位的影响.在下部各向异性体规模明显大于上部各向异性体或表现为层状特征的情况下,上部各向异性体在两个水平方向上的尺度差异较大,可以看作准二维体时容易发生相位超象限;当上部各向异性体在两个水平方向上尺度相近表现为规则三维体时,要产生相位超象限的现象则需要各向异性体具有更高的各向异性比.在同等条件下,增加各向异性体的各向异性比更容易发生相位超象限;而各向异性走向方位角的变化将直接影响到发生相位超象限的范围.对于准二维模型引起相位超象限的条件,沿用二维模型的近似解析分析方法,进一步构建了基于各向异性体的电导率、背景电导率以及各向异性走向角的相位超象限指标函数,从而更加直观地解释在二维或准二维条件下发生相位超象限现象的模型参数特征.     

Ciliates in the Marsh Wetlands of Chongming Island: Taxonomy of Five Species and a Species List

To clarify the confusion surrounding species identification and state intraspecific variations, this research studied the morphological taxonomy of five species, Kentrophyllum cf. setigerum Petz et al., 1995; Zosterodasys shumerica Aliev, 1990; Frontonia tchibisovae Burkovsky, 1970; Neourostylopsis orientalis Chen et al., 2013; and Apoholosticha cf. sinica Fan et al., 2014, which were collected from Chongming Island's marsh wetlands. Kentrophyllum cf. setigerum possesses less somatic kineties than K. setigerum(19–26 right and 18–25 left kineties vs 35–40 right and 30 left kineties). Whether Z. shumerica is identical to Z. transversa Foissner et al., 1994, which was presented in a previous report, was negated. The improved diagnosis for the species is provided. Frontonia tchibisovae was confirmed to have three or four micronuclei, and the number of kinetosome rows in its peniculus 3 varied between China and Russia populations. The new population of N. orientalis bears cortical granules, which differs from the original population that has an arrangement of rows across the dorsal bristles. For A. cf. sinica, there are colorless cortical granules on the ventral side of the new population, whereas in the previously reported populations bright orange, spherical granules were clustered around dorsal cilia. Additionally, we sequenced the small-subunit(SSU) rRNA genes of K. cf. setigerum, N. orientalis, and A. cf. Sinica, and compared the new and reported populations. For the first time, we also provide a species list, including 33 ciliates collected from the wetlands based on living observation and silver staining.     

新疆三大山区可降水量时空分布特征

利用美国宇航局(NASA)发布的2003年1月～2015年12月的AIRS Standard Physical Retrieval Edition 6. 0中的level2的反演数据,对新疆及其周边地区——特别是三大山区近13 a的可降水量的时空分布特征进行了研究。结果表明,从空间分布看,可降水量高值区主要集中在盆地地区,尤其在塔里木盆地、准噶尔盆地及吐鲁番盆地。低值区主要分布在新疆南部的昆仑山脉和北部的阿尔泰山脉。最高值达14. 74 mm,最低值达1. 92 mm;新疆及其周边地区可降水量所有格点13a平均值来看,总体上,夏季最高,冬季最低。从时间分布看,对新疆及其周边地区、天山、昆仑山和阿尔泰山4个研究区域分别进行区域平均,发现以上4个区域年变化呈单峰型,从1～7月的可降水量逐渐增加,8～12月份的可降水量逐月减少;可降水量的整体年际变化趋势是一致的,2003—2010年呈上升趋势,2010—2015年呈下降趋势。     

云南快速更新循环数值预报系统及其12小时降水预报检验与改进

以中尺度WRF模式为基础,参照北京地区高分辨率快速更新循环同化系统,建立了云南快速更新循环数值预报系统(WRF-RUC)。为了充分了解该系统在云南省的预报性能,对预报结果进行个例和2016年6~7月检验。结果表明:快速更新循环同化数值预报系统能进行强降水过程预报,但与业务化“区域WRF数值预报系统”预报结果相比,12h降水预报评分较低。通过个例数值试验表明WRF-RUC系统进行本地化参数方案试验,挑选适合云南省的物理方案,是系统预报效果改进的有效途径。     

Monitoring thermal field,humidity field and energy balance over heterogeneous surfaces in the typical valley-city

Journal of Geographical Sciences - Land use and land cover (LULC) alteration has changed original energy balance and heat fluxes between land and atmosphere, and thus affects the structure...     

多源数据的嫦娥四号着陆点定位

嫦娥四号着陆点的精确定位对于工程任务安全高效实施至关重要。本文基于嫦娥二号正射影像、LROC NAC正射影像、嫦娥四号降落相机影像、嫦娥四号监视相机影像等多源数据,利用影像特征匹配定位和单像视觉测量定位技术,确定了嫦娥四号着陆点的精确位置为(177.588°E,45.457°S)。本研究结果对综合利用多源数据深入开展着陆区科学研究具有重要意义。