基于旋翼无人机观测的雾天和霾天VOCs垂直分布特征研究

为研究雾和霾天气下VOCs时空变化特征,于2020年11月19日—2021年1月15日在江苏省东海国家气象观测站进行为期58 d的外场观测试验。利用自主研发的多旋翼无人机捕获2次辐射雾和2次霾天气过程,获得气温、气压、相对湿度、风向、风速、VOCs、O₃等7种要素100多条垂直廓线。结果表明：时间上,霾过程夜间VOCs体积浓度(0.225～0.253 ppm(parts per million, 1 ppm=10^-6))明显高于白天(0.191～0.205 ppm),雾形成前体积浓度(0.121～0.239 ppm)显著高于雾过程(0.056～0.209 ppm)。雾过程中VOCs体积浓度与雾强度变化相反,雾层高度与VOCs体积浓度剧烈变化高度一致,雾层(<200 m)中VOCs体积浓度(0.172～0.178 ppm)明显减小,显著低于雾形成前(0.195～0.240 ppm),雾层以上浓度变化大,雾结束后1 h内保持雾过程中分布特点。雾对逆温层中的水溶性污染物有清除作用,VOCs体积浓度和O₃质量浓度均下降。     

最优气候相似法及其在降水预报中的应用

介绍了一种短期气候预测方法———最优气候相似法 ,并应用于张家界地区 1 999～ 2 0 0 2年 5～ 7月总降水预报中 ,结果显示最优气候相似法能够有效地提高短期气候的预测能力 ,特别对气候异常具有良好的反应能力 ,适合于短期气候业务预报。     

2014年秋季长株潭城市群一次典型霾污染天气过程的气象特征及成因分析

利用长株潭地区地面空气质量监测资料、常规地面气象资料及NCEP再分析资料和MODIS火点监测资料,结合HYSPLIT4后向轨迹模式,对2014年10月1718日长株潭地区一次严重霾天气过程的空气污染特征和成因进行综合分析。研究表明,长株潭地区此次严重霾天气污染事件的主要污染物为PM2.5,安徽南部和江西西北部地区秸秆焚烧产生的颗粒物,经高空偏东北气流引导输送到长株潭地区,是这次大范围烟霾天气的主要来源。长株潭地区西部高空槽区宽广,槽前西南气流较为强盛,地面受均压场控制,水平风速弱,为严重霾污染天气的维持提供了有利的环流条件。中低层逆温和大气底层湿度的增加,使污染物粒子不断累积;近地面连续静（小）风和风向的频繁转变,不利于污染物粒子的水平扩散;中下层弱的下沉气流、较低的混合层高度有利于污染物的垂直累积,为此次重度霾污染天气的发展、加强提供了有利的气象条件。     

Sediment transport in analogue flume models compared with real‐world sedimentary systems: a new look at scaling evolution of sedimentary systems in a flume

Evolution of sedimentary systems at large temporal and spatial scales cannot be scaled down to laboratory dimensions by conventional hydraulic Froude scaling. Therefore, many researchers question the validity of experiments aiming to simulate this evolution. Yet, it has been shown that laboratory experiments yield stratigraphic responses to allocyclic forcing that are remarkably similar to those in real‐world prototypes, hinting at scale independency with strong dependence on boundary conditions but weak dependence on the actual sediment transport dynamics. This paper addresses the dilemma by contrasting sediment transport rules that apply in the laboratory with those that apply in real‐world geological systems. It is demonstrated that the generation of two‐dimensional stratigraphy in a flume can be simulated numerically by the non‐linear diffusion equation. Sediment transport theory is used to demonstrate that only suspension‐dominated meandering rivers should be simulated with linear diffusion. With increasing grain‐size (coarse sand to gravel) and shallowness of river systems, the prediction of long‐term transport must be simulated by non‐linear, slope‐dependent diffusion to allow for increasing transport rates and thus change in stratigraphic style. To point out these differences in stratigraphic style, three stages in infill of accommodation have been defined here: (i) a start‐up stage, when the system is prograding to base level (e.g. the shelf edge) with no sediment flux beyond the base‐level point; (ii) a fill‐up stage, when the system is further aggrading while progressively more sediment is bypassing base level with the progression of the infill; and (iii) a keep‐up stage, when more than 90% of the input is bypassing the base level and less than 10% is used for filling the accommodation. By plotting the rate of change in flux for various degrees of non‐linearity (varying the exponent in the diffusion equation) it was found that the error between model and real‐world prototype is largest for the suspension‐dominated prototypes, although never more than 30% and only at the beginning of the fill‐up stage. The error reduces to only 10% for the non‐linear sandy‐gravelly and gravelly systems. These results are very encouraging and open up ways to calibrate numerical models of sedimentary system evolution by such experiments.     

The role of diagenesis and depositional facies on pore system evolution in a Triassic outcrop analogue (SE Spain)

This study aims at unravelling the diagenetic history and its effect on the pore system evolution of the Triassic redbeds exposed in SE Spain (TIBEM¹), an outcrop analogue of the TAGI (Trias Argilo-Gréseux Inférieur) reservoir (Berkine-Ghadames Basin, Algeria). Similar climatic, base level and tectonic conditions of aforementioned alluvial formations developed analogue fluvial facies stacking patterns. Furthermore, interplay of similar detrital composition and depositional facies in both formations resulted in analogue early diagenetic features. Petrographic observations indicate lithic subarkosic (floodplain facies) and subarkosic (braidplain facies) compositions which are considered suitable frameworks for potential reservoir rocks. Primary porosity is mainly reduced during early diagenesis through moderate mechanical compaction and formation of K-feldspar overgrowth, gypsum, dolomite and phyllosilicate cements. Early mesodiagenesis is testified by low chemical compaction and quartz cementation. Telodiagenetic calcite filling fractures and K-feldspar dissolution determined the final configuration of analysed sandstones. Mercury injection-capillary pressure technique reveals overbank deposits in the floodplain as the least suitable potential reservoirs because of their lowest open porosity (OP < 16%), permeability (k < 5 mD) and small dimensions. On the other hand, braidplain deposits show the highest values of such properties (OP up to 31.6% and k > 95 mD) and greater thickness and lateral continuity, so being considered the best potential reservoir. The accurate estimation of TIBEM microscale attributes can provide important input for appraisal and enhanced oil recovery performance in TAGI and in others reservoirs consisting on similar fluvial sandy facies.     

离岸型背景风和海陆风对珠江三角洲地区灰霾天气的影响

不同类型的背景场和海陆风对珠江三角洲地区大气灰霾有不同的影响。作者主要利用空气质量模式系统Models-3 (MM5/SMOKE/CMAQ)研究离岸型背景风和海陆风对珠江三角洲一次灰霾天气的影响, 结果表明, 中尺度气象模式MM5对珠江三角洲地区这次灰霾天气的气象模拟, 较好地模拟了风速和风向的变化。多尺度空气质量模式CMAQ模拟出了PM10浓度的变化, 与观测值比较一致。在这次灰霾天气过程中, 由于离岸型背景风与陆风风向一致, 在陆风维持的情况下, 内陆源区的PM10被输送到沿海地区, 导致沿海城市和海面上PM10浓度比较高; 而在海风维持的情况下, 海风与离岸型背景风方向相反, 造成海风较小, 致使整个珠江三角洲地区灰霾天气都比较严重。敏感性试验结果表明离岸背景风和海陆风的相互作用对灰霾天气的生成与分布有重大的影响。     

风廓线雷达在重污染天气与逆温层关系研究中的应用

本文利用气象要素地面观测和环境空气质量监测数据,结合对流层风廓线雷达探测资料,深入研究了2013-2019年发生在青岛地区的65个重污染天气的逆温层变化特征及其与重污染天气的关系.结果表明:(1)青岛地区的重污染天气主要发生在12月至次年1月,重污染发生当日的空气质量指数(Air quality iudex AQI)有...     

基于水电比拟方法的山东南四湖上级湖流场研究

利用水电比拟方法模拟了南四湖流场结构。同时,基于HAMSOM模式,对其流场进行了数值模拟,所得结果与水电比拟结果一致,两者平均相关系数在0.94以上,表明水电比拟实验技术路线可行,流场基本结构准确。该方法适用于低流速大流场的模拟。流场结构分析表明,湖区流速在汛期为cm/s量级,非汛期仅为mm/s量级。其中,在南阳湖北部...     

鲨肝刺激物质类似物基因在大肠杆菌中的表达与产物活性分析

构建了鲨肝刺激物质类似物基因片段的原核表达载体质粒 (pET-sHSS) ,转化大肠杆菌后通过IPTG诱导获得原核表达产物 ,并利用凝胶层析方法对表达产物进行了分离纯化 ;进一步利用MTT比色法研究了该重组产物对肝癌细胞株SMMC -7721的增殖影响。结果表明 ,在1mmol/L的IPTG的诱导下 ,鲨肝刺激物质类似物基因片段在大肠杆菌BL21菌株中获得表达 ,表达产物的相对分子质量大小约为17500u,占菌体可溶性蛋白总量的38%左右 ;纯化后的产物在低浓度下 (<50ng/L)具有明显刺激SMMC7721细胞株增殖的活性 ,高浓度下 (>100ng/L)则明显抑制该肿瘤细胞株的生长 ,与天然鲨肝刺激物质的生物活性类似     

多种风电场风速预报订正方法的适用性研究与集成应用

以内蒙古中部某风电场为实验风电场,采用随机森林（Random forest,RF）方法、相似误差订正（Analogue correction of errors,ACE）方法以及概率密度匹配方法（Probability density function matching method,PDF）分别对风电场风速预报进行订正及适用性研究。结果表明：3种方法在各季均对中尺度天气预报模式（Weather research and forecasting model, WRF）风速预报具有不同程度的订正效果,RF方法可以有效改善WRF误差较大的问题,但兼具误差过分放大情况,ACE方法和PDF虽然对较大误差的改善能力不及RF方法,但是能够较好地控制误差过分放大问题。此外,3种方法针对小于5 m·s^-1的小风速段,订正效果不理想,随着风速的增加,订正能力逐渐增强。参照预报模型各自的优势,尝试开展多种预报模型的分风速等级集成应用,可以对不同风速等级下的WRF预报起到较好的改善作用。