A neural network method for monitoring snowstorm: A case study in southern China

It has been observed that low temperature, rainfall, snowfall, frost have never occurred over the past 50 years in the southern China, and weather in this area is very complex, so the monitoring equipments are few. Optical and thermal infrared remote sensing is influenced much by clouds, so the passive microwave Advanced Microwave Scanning Radiometer-Earth Observing System （AMSR-E） data are the best choice to monitor and analyze the development of disaster. In order to improve estimation accuracy, the dynamic learn- ing neural network was used to retrieve snow depth. The difference of brightness temperatures of TB18.7v and TB36.sv, TBI8.7H and TB36.sH, TB23,sv and TB89v, TBz3.8H and TB89H are made as four main input nodes and the snow depth is the only one output node of neural network. The mean and the standard deviation of retrieval errors are about 4.8 cm and 6.7 cm relative to the test data of ground measurements. The application analysis indicated that the neural network can be utilized to monitor the change of snow intensity distribution through passive microwave data in the complex weather of the southern China.     

A two-parameter exponential recession model for simulating cropland soil moisture dynamics

To simulate the soil moisture variation in cropland, a two-parameter exponential recession model was derived to depict the recession process of soil moisture in the root zone. The model is based on the assumption that the recession rate of soil water is propor- tional to the potential evapotranspiration rate and the difference of soil water content and steady soil water content. Two parameters in this model are soil texture-dependent recession constant and steady soil water content. The model was calibrated and validated with measured soil water data at two experiment sites in North China with different soil textures and cropping systems. Coefficients of de- termination between measured and model simulated soil water content were all greater than 0.7, indicating that both models gave satis- factory simulation results. Results showed that values of two parameters mentioned above are both larger for finer soil than those for coarser soil. At the same potential evapotranspiration rate and soil water content, the recession rate of finer soil is usually lower than that of coarser soil. The proposed model can be used in irrigation management to predict approximate date for irrigation, as well as be em- bedded into watershed hydrological models to estimate the antecedent precipitation index.     

Simulation and causes of eastern Antarctica surface cooling related to ozone depletion during austral summer in FGOALS-s2

Two parallel sets of numerical experiments （an ozone-hole simulation and a non-ozone-hole simulation） were performed to investigate the effect of ozone depletion on surface temperature change using the second spectral version of the Flexible Global Ocean-Atmosphere-Land System model （FGOALS-s2）, focusing on the eastern Antarctica （EA） continent in austral summer. First, we evaluated the ability of the model to simulate the EA surface cooling, and found the model can successfully reproduce the cooling trend of the EA surface, as well as the circulation change circling the South Pole in the past 30 years. Second, we compared the two experiments and discovered that the ozone depletion causes the cooling trend and strengthens the circumpolar westerly flow. We further investigated the causes of the EA surface cooling associated with the ozone hole and found two major contributors. The first is the ozone-hole direct radiation effect （DRE） upon the surface that happens because the decrease of the downward longwave （LW） radiation overcomes the increase of the downward shortwave （SW） radiation under clear sky. The second is the cloud radiation effect （CRE） induced by ozone depletion, which happens because the decreased downward SW radiation overcomes the increased downward LW radiation in the case of increased cloud. Although the CRE is theoretically opposite to the DRE, their final net effect makes comparable contributions to the EA surface cooling. Compared with the surface radiation budget, the surface heat flux budgets have a much smaller contribution. We additionally note that the CRE is basically ascribed to the circulation change.     

L波段探空资料的人工干预处理方法

探空站目前使用的业务系统软件具有"自动修改温压湿曲线"和数据异常的自动纠偏功能(自动纠正),在实际工作应用中单纯依赖自动纠正功能来处理异常数据,会造成探测数据失真或不准确。为避免业务软件自动纠正功能的缺陷,确保取准、取全第一手探空资料,有必要对异常数据进行人工干预。通过东源探空站遇到的几个事例来说明人工干预的必要性和人工干预处理方法及注意事项,以供探空台站人员参考。     

基于罗德里格矩阵的混合最小二乘方法在三维激光中的应用

介绍了基于罗德里格矩阵的混合最小二乘坐标转换模型及精度,通过三维激光点云配准与坐标转换实验的结果表明,基于罗德里格矩阵的混合最小二乘方法的效果及精度明显高于基于罗德里格矩阵的最小二乘方法,说明该方法的可行性。     

五种中草药复方体外激活花鳗鲡(Anguilla marmorata)外周血白细胞活性的评价

作为典型的降河洄游鱼类,花鳗鲡(Anguilla marmorata)在我国主要分布于长江下游及以南水域。中草药作为抗生素等化学类渔药的绿色替代品,对养殖鱼类具有抗菌、消炎、促生长等多种功效。为研究中草药复方在花鳗鲡病害防治中的作用,扩大水产养殖业渔药研制与应用的选择,采用非连续性密度梯度离心法对花鳗鲡外周血白细胞的分离体系进行了优化,试验设置了密度分别为1.031、1.043、1.056、1.067、1.090 g/mL的五种分离液,分别采用染色观察法和流式细胞术检测各分离液中白细胞浓度;以浓度1.0mg/mL的五种复方药液分别与10⁵cell/mL的白细胞悬液共孵育2h后,分别采用NBT法和流式细胞术测定白细胞的呼吸暴发活性和吞噬能力,评价五种中草药复方(多糖复方Dt,白头翁复方Btw,板蓝根复方Blg,大黄复方Dh,百里酚复方Blf)对花鳗鲡外周血白细胞的激活作用。结果显示:1.043g/mL和1.056g/mL的分离液所分离获得白细胞浓度均接近10⁵cell/mL,可在后续实验中叠加使用该两个浓度的分离液分离获得白细胞;流式细胞术检测白细胞浓度比染色观察法更为灵敏准确;5种复方均能显著提高花鳗鲡外周血白细胞的呼吸暴发活性(P<0.05),大小依次为Blg>Dt>Btw>Blf>Dh;Dt和Blg能显著提高白细胞吞噬率(P<0.05),Btw、Blf、Dh也能提高白细胞吞噬率,但差异不显著(P>0.05);5种复方对发生吞噬白细胞比率的影响差异不显著(P>0.05)。     

Settlement distribution and its relationship with environmental changes from the Neolithic to Shang-Zhou dynasties in northern Shandong, China

In this paper, the spatial and temporal distribution of the settlement sites of six periods from the Neolithic Age to the Shang and Zhou dynasties in northern Shandong was investigated using the ArcGIS program, and the relationship between settlement distribution and environmental changes was discussed, based on the proxy records of climatic and environmental change contained in the sediments from three sections at the Shuangwangcheng site and the previous work. The results show that the climate was warm and humid and the sea level was relatively high during the period of 8000-5000 a BP in the study area, and the ancient people lived in the relatively flat （slope of 〈2°） areas at high elevation （20-300 m above sea level）, such as diluvial tableland and alluvial plain. On the other hand, few archaeological sites in the low-lying plain in the west of the study area indicate that few people lived there during that period. This might be attributed to frequent flooding in the area. After 5000 years ago, the scope of human activity extended to the area close to the sea because the relatively colder and drier climate results in sea-level fall, meanwhile the low-lying plain in the west was occupied by the ancient people. The study area of this period was characterized by the rapid development of prehistoric culture, the intensified social stratification and the emergence of early city-states. However, around 4000 a BP, the abrupt change in climate and the increase in frequency and intensity of floods severely disrupted human activities, and eventually led to the decline of the Yueshi culture. During the Shang and Zhou dynasties, the climatic conditions gradually stabilized in a mild-dry state, which promoted the redevelopment and flourish of the Bronze Culture. The previous situation, which was characteristic of sparse human settlements due to freshwater shortage and unfitted conditions for sedentary agriculture, changed during the Shang and Zhou dynasties in northern coastal wetlands.Local residents effectively adapted themselves to the tough environmental conditions by producing sea-salt, which led to the rapid growth of human activities.     

Different discretization method used in coupled water and heat transport mode for soil under freezing conditions

A coupled water and heat transport mode is established based on the Richards equation to study water flow and heat transport in soil during freezing process. Both the finite difference and finite element method are used in the discretization, respectively. Two different computer programs are written and used to simulate an indoor unidirectional frozen test. The freezing depth, freezing rate and temperature variation are compared among lab tests, finite difference calculation simulation and finite element calculation simulation. Result shows that: the finite difference method has a better performance in freezing depth simulation while the finite element method has a better performance in numerical stability in one-dimensional freezing simulation.     

On the relation of mid-infrared emission with the gamma-ray properties of Fermi-detected BL Lac objects

We present the Wide-field Infrared Survey Explorer (WISE) photometric data of 158 Fermi-detected BL Lacs and investigate the nature of their mid-infrared (MIR) continuum emission. In the [3.4]-[4.6]-[12] μm color–color diagram, nearly all their colors lie within the WISE Blazar strip (WBS), which is an effective diagnostic tool to separate sources dominated by non-thermal radiation from those dominated by thermal radiation. This feature indicates that their MIR emission is predominantly non-thermal. This argument is further supported by the strong radio-MIR flux correlation. We derive their MIR spectral indices and compare them with the near-infrared (NIR) spectral indices. We find that there is a prevalent steepening from MIR spectrum to NIR spectrum. The low-frequency-peaked BL Lacs (LBLs) have on average a larger MIR spectral index and a higher MIR luminosity than the high-frequency-peaked BL Lacs (HBLs), and the intermediate-frequency-peaked BL Lacs (IBLs) appear to bridge them. The MIR-γ-ray flux correlation is highly significant. A strong positive correlation is also found between the MIR and γ-ray spectral indices. The γ-ray-MIR loudness is significantly correlated with the synchrotron peak frequency. Finally we propose that the γ-rays are highly associated with the MIR emission from the jet, and the γ-ray emission is likely from the synchrotron self-Compton process for the Fermi-detected BL Lacs in our sample.