NUMERICAL PREDICTION OF AN EXTREME RAINSTORM OVER THE PEARL RIVER DELTA REGION ON 7 MAY 2017 BASED ON WRF-ENKF

An ensemble Kalman filter based on the Weather Research and Forecasting Model (WRF-EnKF) is used to explore the effectiveness of the assimilation of surface observation data in an extreme local rainstorm over the Pearl River Delta region on 7 May 2017. Before the occurrence of rainstorm, the signals of weather forecasts in this case are too weak to be predicted by numerical weather model, but the surface temperature over the urban area are high. The results of this study show that the wind field, temperature, and water vapor are obviously adjusted by assimilating surface data of 10-m wind, 2-m temperature, and 2-m water vapor mixing ratio at 2300 BST 6 May, especially below the height of 2 km. The southerly wind over the Pearl River Delta region is enhanced, and the convergence of wind over the northern Guangzhou city is also enhanced. Additionally, temperature, water vapor mixing ratio and pseudoequivalent potential temperature are obviously increased over the urban region, providing favorable conditions for the occurrence of heavy precipitation. After assimilation, the predictions of 12-h rainfall amount, temperature, and relative humidity are significantly improved, and the rainfall intensity and distribution in this case can be successfully reproduced. Moreover, sensitivity tests suggest that the assimilation of 2-m temperature is the key to predict this extreme rainfall and just assimilating data of surface wind or water vapor is not workable, implying that urban heat island effect may be an important factor in this extreme rainstorm.     

基于Sentinel-2的潮间红树林提取方法

位于潮间带的红树林可能在高潮时被海水淹没的特点,使得传统的植被提取方法在红树林信息提取方面存在局限性。本文在对比分析了出露的红树林、高潮水位淹没的红树林、海水水体的光谱特征后,提出了一种利用归一化潮间红树林指数（NIMI）提取潮间带红树林的方法。该指数是由植被强吸收的红波段,强反射的两个红边波段和近红外波段组成的归一化表达式。利用该指数对福建省龙海九龙江口湿地的红树林进行了分类提取,提取结果与高分二号影像目视验证和现场调查结果进行了对照。结果显示,该方法提取红树林的用户精度达到93.98%,并显著优于利用归一化水体指数（NDWI）、归一化植被指数（NDVI）及随机森林的结果。     

泥蚶(Tegillarca granosa)生长因子受体结合蛋白2(GRB2)基因的克隆与表达分析

通过已构建的泥蚶(Tegillarca granosa)转录组文库, 利用SMART RACE技术扩增得到泥蚶Tg-GRB2基因的全长cDNA序列, 并对其生物信息学、组织表达及发育阶段表达特征进行了分析。结果表明, 泥蚶Tg-GRB2 cDNA全长1283bp, 开放阅读框为708bp, 编码236个氨基酸; 蛋白结构预测显示, Tg-GRB2蛋白包含SH3-SH2-SH3三个功能域, SH2结构域由两端的α-螺旋和中间反向平行的β-折叠片构成, SH3结构域主要由β-折叠片组成, 具备典型的结构特征; 氨基酸序列比对发现, Tg-GRB2与脊椎动物的同源性为62.1%—63.8%, 而与玻璃海鞘和日本血吸虫同源性较低。qRT-PCR检测结果显示: Tg-GRB2 mRNA在泥蚶血液、斧足、鳃、外套膜、闭壳肌、内脏团6个组织中都有表达, 而在血液中的表达量极显著地高于其它组织; 在泥蚶的不同发育阶段中, Tg-GRB2 mRNA在 2—4细胞胚胎、原肠胚、担轮幼虫、D形幼虫中均有较高的表达量, 而在D形幼虫中表达量最高, 表明Tg-GRB2基因在泥蚶早期发育中发挥重要调节作用。     

基于高分二号卫星数据的农作物分类方法研究

针对目前高分二号卫星数据(GF-2)有较高的空间分辨率而在农业领域应用较少和农作物分类普遍存在同谱异物和同物异谱的现象,以辽宁省沈阳市苏家屯区以西的新开河村周边为试验基地,利用最佳波段组合指数法(OIF)对所选取的高分二号(GF-2)卫星数据的纹理特征和植被指数以及波段信息进行筛选,选取最佳的波段组合,以增加分...     

基于GF-2影像西藏桑耶地区岩性-构造遥感解译

西藏桑耶地区位于青藏高原中南部,区内切割强烈,地势陡峻,属于高山峡谷区。为提高区域地质调查野外工作效率,在调查中率先开展了遥感解译研究。在充分收集已有资料的基础上,通过对GF-2卫星数据进行预处理和影像增强,结合野外验证建立了各地质要素的遥感解译标志,实现了区内不同地层岩性、侵入岩、断裂和褶皱等地质要素的提取,最终编制了研究区1:5万遥感地质解译图,为区域地质调查提供了数据支撑。结果表明: 各地质要素在GF-2数据上均有良好反映,完全满足1:5万尺度的遥感地质解译和编图的需要,充分显示出该卫星数据在区域地质调查等工作中具有良好的应用前景。     

缢蛏天然抗性相关巨噬蛋白2(Sc-Nramp2)基因克隆及其在副溶血弧菌刺激下的表达分析

克隆得到缢蛏天然抗性相关巨噬蛋白2（Sc-Nramp2）基因的cDNA全长序列3 681 bp,该基因的开放阅读框有1 776 bp,编码591个氨基酸,预测分子量为65.86 kDa;其结构具有Slc11蛋白家族的典型特征,包括有10个典型的跨膜结构和2个糖基化位点。Sc-Nramp2基因3'-UTR有2个类似于脊椎动物Nramp2中铁反应控制蛋白结合位点;同源性分析表明,Sc-Nramp2和太平洋牡蛎Nramp2-like的同源性最高为71.6%。实时荧光定量PCR结果表明,Sc-Nramp2基因在闭壳肌、外套膜、肝胰腺、斧足、水管和鳃6个组织中均有表达,其中肝胰腺中的表达量最高,其次是鳃,与其他组织均有极显著性差异（P<0.01）;注射副溶血弧菌后,肝胰腺中Sc-Nramp2基因的表达量较对照组显著上调（P<0.01）,且表达量呈现先上升后下降的趋势,在12 h时达到最大表达量,推测Sc-Nramp2基因参与了缢蛏非特异性免疫应答反应。     

不同植被红边指数在城市草地健康判别中的对比研究

遥感红边指数与表征绿色植物生长状况的重要生化参数有密切的关系,是植被长势监测的重要因子。为寻找出最适用于城市草地生长状况监测的红边指数,本文基于Sentinel-2A数据,对比分析了不同红边指数在城市草地健康状况估算方面的差异。本文以福州市和厦门市的城市草地为例,在全面分析各种健康水平草地光谱响应特征差异的基础上,选取了6种与草地生化参数相关的红边指数,即红边位置REP、地面叶绿素指数MTCI、归一化差值红边指数NDRE1、新型倒红边叶绿素指数IRECI、红边叶绿素指数CI_red-edge以及叶绿素吸收指数MCARI2,然后采用独立样本T检验及欧式距离对这6种红边指数在草地健康判别中的优劣进行了定量对比。结果表明：IRECI指数对草地健康状况最为敏感,该指数在不同健康等级草地的值域区间和均值都存在显著性差异,其判别总精度均大于85%;NDRE1和MCARI2指数次之,其他3个指数则难以判别草地的健康状况。因此,在基于Sentinel-2A影像的城市草地健康遥感判别中,推荐使用IRECI指数。     

河流-河口-近海连续体碳循环研究进展

河流-河口-近海连续体(简称连续体)是连接陆地和大洋的过渡地带,也是目前全球碳收支估算的薄弱环节.这个复杂的海陆交互生态系统不仅可以通过光合作用、溶解作用吸收大气中的CO2,陆地和流域光合作用或化学风化作用固定的碳也可以被横向输送到陆架和大洋中.本文以国际上著名的切萨皮克湾以及长江-长江口-东海等为例,综述了连续体碳循...     

TiO2光催化降解微污染水中腐殖酸的研究

为探讨TiO2光催化法处理微污染水中腐殖酸的规律,利用悬浮状的TiO2颗粒在紫外光的照射下催化降解含有腐殖酸污染物的水样,设计正交试验研究pH值、TiO2的投加量、腐殖酸溶液初始浓度、曝气量和温度等对腐殖酸降解效果的影响及规律。结果表明:pH=3.5时,TiO2的投加量为1.0 g/L、曝气量为0.12 m3/h、温度为18℃时,最佳有机物降解效果为96.83%;TiO2光催化法对微污染水中的腐殖酸能够有效降解。     

Assessment of 2DH and pseudo‐3D modelling platforms in a large saline aquatic system: Lake Urmia,Iran

The main objective of this paper is to provide comparative quantitative examinations on the capabilities of two‐dimensional horizontal and pseudo‐three‐dimensional (3D) modelling approaches for simulating spatial and temporal variability of the flow and salinity in Lake Urmia, Iran. The water quality in the lake has been an environmentally important subject partly because this shallow hypersaline aquatic ecosystem is considered to be one of the largest natural habitats of a unique multicellular organism, Artemia urmiana. This brine shrimp is the major food source for many of the protected and rare shorebirds that visit the lake. A. urmiana can grow and survive in certain ranges of salinity, and their disappearance could lead to an alteration of existing equilibria. The lake has also experienced considerable man‐made changes during the past three decades. A newly built crossing embankment almost divided the lake into two northern and southern halves. A relatively small opening of 1.25 km in the new embankment provides water connections between the two halves. As a result, the flow and salinity regimes have been significantly changed. This might have had adverse serious impacts on the lake ecosystem. In the current study, the two‐dimensional horizontal hydrodynamic model has been found to provide reasonable predictions for the flow regime in the lake, whereas its salinity predictions have not been consistent with the field observations. The pseudo‐3D model has produced results fairly close to the salinity measurements and its temporal and spatial variations. The pseudo‐3D model has been used for evaluating the embankment effects on the lake hydrodynamics and on the salinity conditions. The effectiveness of introducing a different number or length of openings in the embankment for restoring the pre‐embankment conditions has also been examined. These remedy options have been found not to offer substantial improvements to the lake's existing ecosystem. Copyright © 2013 John Wiley & Sons, Ltd.