中全新世黄河流域耕地格局重建及对原生植被的影响(英文)

Yangshao culture is the most important mid-Holocene Neolithic culture in the Yellow River catchment,and thus,a study on the impact of human activities on the environment is important.In the current study,the distribution pattern of the cultivated land in late Yangshao culture is reconstructed using GIS tool and site domain analysis(SDA).The results show that the cultivated land during 5.5-5.0 ka BP was mainly distributed in the Weihe River valley,Luohe River valley,northwestern Henan Plain,Fenhe River valley and eastern Gansu region,especially concentrated in the Xi’an-Baoji line of the Weihe River valley.At that time,at least 37,000 km 2 of lands were reclaimed in the middle and lower reaches of the Yellow River,and 132,000 km 2 of lands were affected by agricultural activities.Human activities had become the driving force of land use/land coverage.Charcoal records indicate that the ancestors of Yangshao culture burnt forests for reclamation,leading to the decrease of arbor pollen at 5 ka BP in core areas of the Yangshao culture.The areas that were significantly affected by human activities accounted for 3.2% of the Yangshao culture influenced area,while the moderately affected areas accounted for 20.1% of Yangshao culture influenced area.Meanwhile,92% of the land areas on the edge and outside of the Yangshao culture influenced area were not affected by human activities.The arbor pollen in these areas did not decrease until 4.0 ka BP.     

贵州罗甸晚二叠世辉绿岩及其区域构造意义

黔东南罗甸辉绿岩为拉斑系列岩石,其主量元素以高TiO2（2.36%～2.57%）、高CaO（9.40%~10.31%）、低MgO（5.65%~6.93%）,低碱且Na2O>K2O为特征;稀土含量（ΣREE= 164.9×10-6~ 187.3×10-6）较高,反映轻稀土富集,重稀土亏损;Eu正异常（δEu=1.22~1.26）,球粒陨石标准化配分曲线具有右倾分布特征。对辉绿岩中锆石进行的LA-ICP-MS U-Pb定年分析获得其谐和图下交点年龄为255.0±0.62Ma,代表岩体结晶时代。结合区域地质分析认为,罗甸辉绿岩可能起源于接近于原始的地幔橄榄岩的部分熔融作用,岩浆在快速上升过程中可能受到地壳物质的混染。罗甸辉绿岩具有与峨眉山玄武岩相似的地球化学特征,其形成年龄与峨眉山玄武岩的主喷发期基本同时。综合分析认为,黔东南晚二叠世辉绿岩是峨眉山玄武岩同质异相岩浆活动的产物,黔东南罗甸—望谟一带处于峨眉山玄武质岩浆活动的东部边缘地带。     

Sources of monsoon precipitation and dew assessed in a semiarid area via stable isotopes

Precipitation is usually the primary source of water for the hydrological cycle in a semiarid area. However, dew occurs frequently and affects water circulation dramatically in the west of Jilin Province in China. Measurements of the amount of dew formed and precipitation were carried out from July 2012 to October 2013 in the Momoge Natural Reserve. The results indicated that moisture from primary precipitation in the summer originated from the East Asian monsoon and was affected by the atmospheric circulation in the middle and high latitudes of Eurasia in the winter. The dew amount was approximately 19.44 mm (approximately 5% of the total rainfall amount), consisting of the evapotranspiration in the local area and atmospheric moisture. Dew also supplies nutrients to the local vegetation. The maximum contribution of total nitrogen, total phosphorus, and potassium in unit corn area could reach 288.60, 27.46, and 291.63 mg/m² in half a month, respectively. The wind speed, relative humidity, and lowest temperature were the primary factors that dramatically affected dew formation and amount. As an additional source of fresh water, dew not only had a positive impact on the ecosystem in arid and semiarid zones but also played an important role in the local water cycle and other ecological processes. This research has important implications for water circulation and land use management.     

基于GIS的青藏高原史前交通路线与分区分析

青藏高原自然环境恶劣,但并非是生命的禁区。确切证据表明,末次冰消期人类已扩张至高原地区,并通过长期实践形成了较为稳定的交通路线格局。通过构建自然因子模拟—遗址分布校正方法,利用GIS得到青藏高原史前交通路线模拟结果,再结合考古证据对模拟路线进行印证。依据模拟结果将高原分为以下4个区：东北区、东南区、西南区以及西北无人区。其中东北区路线遗址点密度高,落入路线内的遗址点数量占总数的88.56%。路线形成于旧石器时期,其方向为东西向,密切联系东北区的内部,并向外沟通黄土高原与北方地区,其形成与发展为彩陶、粟黍、小麦的传播以及丝绸之路的形成奠定了基础。东南区路线为南北走向,北与黄河上游地区连接,南与四川盆地、云贵高原沟通,加强了南北方地区的文化交流,是民族融合与交流的大走廊。西南区位于高原的腹心地带,模拟的路线体现了人类对青藏高原主体的征服,其线路总长度4602.32 km为3个区域内最长,是人类向高原进军的第2条重要通道。西北无人区主要为高寒荒漠区,其自然环境极端恶劣不适宜人类生存,故无路线分布。     

Ground-Based Atmospheric CO2, CH4, and CO Column Measurements at Golmud in the Qinghai-Tibetan Plateau and Comparisons with TROPOMI/S5P Satellite Observations

Measurements of carbon dioxide(CO₂), methane(CH₄), and carbon monoxide(CO) are of great importance in the Qinghai-Tibetan region, as it is the highest and largest plateau in the world affecting global weather and climate systems. In this study, for the first time, we present CO₂, CH₄, and CO column measurements carried out by a Bruker EM27/SUN Fourier-transform infrared spectrometer(FTIR) at Golmud(36.42°E, 94.91°N, 2808 m) in August 2021. The mean and...     

中学生地理空间思维能力提高的影响因素——基于甘肃省白银市第一中学高一学生的实证研究

地理空间思维能力是人类认识地理环境的基本能力,也是学生的地理核心素养,其影响因素及作用机制是当前迫切需要解决的基础理论问题。本文初步假设一般智力水平、生活环境特征、地理学习兴趣、地图使用习惯、地理问题关注习惯、方向敏感程度、地理专业知识等7个因素为地理空间思维能力提高的影响因素。通过样本测试取得甘肃省白银市第一中学高一年级126个学生样本的地理空间思维能力及其假设的7个影响因素数据。借助SPSS 23.0软件,运用相关分析、独立样本T检验、单因素和多元线性回归分析等方法,证实一般智力水平、地理专业知识、地图使用习惯是学生地理空间思维能力提高的必要条件,地理学习兴趣是其重要条件,上述4个因素为地理空间思维能力提高的影响因素,其作用强度从大到小依次为：一般智力水平>地理专业知识>地图使用习惯>地理学习兴趣。其中一般智力水平和地理专业知识对地理空间思维能力有较强的预测作用。此外,还发现无论地理空间思维能力还是7个假设的影响因素,均未发现有显著的男女性别差异,说明上述规律具有性别普适性。     

西太平洋中南部冬季悬空波导统计分析及成因初探

利用2015年11月—2016年1月船载GPS探空数据和欧洲中心ERA-Interim再分析资料,对西太平洋中南部海域悬空波导现象进行了统计分析。探空资料分析表明：该区域出现悬空波导的发生概率为47%,平均高度为1 393 m,平均厚度为205 m,平均强度为11.7 M-unit,平均截止波长为2.7 m。悬空波导发生时,天气晴朗,云量较少,以积云为主。进一步分析发现5～30°N范围内悬空波导发生概率高达77%,在800 hPa左右高度存在强悬空波导现象。ERA-Interim再分析资料表明强悬空波导出现在巨大反气旋运动区,副热带高压内部缓慢下沉引起的干燥大气与海洋边界层内湿润的、上升运动大气相遇,在800 hPa附近形成较强的相对湿度梯度和逆温,导致强悬空波导的发生。     

GIS and ANN-based spatial prediction of DOC in river networks: a case study in Dongjiang, Southern China

This paper investigates the use of an artificial neural network (ANN) model to predict dissolved organic carbon (DOC) in a river network and evaluates the impacts of watershed characteristics on stream DOC. Samples and relevant environmental variables were obtained from field sampling at 28 hydrological response units (HRUs) and a MODIS/SRTM DEM satellite image. HRUs can provide reliable spatial interpolation for filling data gaps and incorporate potential spatial correlation among observations in each ANN neuron. The process and results of neural network modeling were assessed by deterministic and statistical methods and spatial regression kriging. The spatial prediction results show that ANN, using improved back propagation algorithms of 7-15-1 architecture, was the optimal network, by which predictions maintained most of the original spatial variation and eliminated smoothing effects of RK. The sum of the relative contributions of four sensitive variables, including soil organic carbon density, geographic longitude, surface runoff and Chl a in river water, was >75 %. A minor prediction error of ~6 % was found in HRUs of open shrublands, but HRUs of urban and croplands had an error of 24–30 %. This pattern exemplifies anthropogenic impacts in urban areas on stream DOC and agricultural activities in croplands. The usefulness of ANN modeling-based GIS in this study is demonstrated by depiction of spatial variation of stream DOC and indicates the benefits of understanding sensitive factors for watershed impact assessments.     

垂直能量螺旋度在双流机场雷暴预报中的应用

文章引入垂直能量螺旋度指数的概念,并利用NCEP 1°×1°再分析资料,将其应用于双流机场2011年5月8—9日出现的雷暴天气过程,并对2009—2012年双流机场出现的32次雷暴天气过程进行统计,验证垂直能量螺旋度指数的有效性及普适性。结果表明,该指数综合反映了对流天气发生时的热力效应和动力效应,有明确的物理意义,是诊断和预报强对流天气的有效指数;垂直能量螺旋度对预报双流机场未来3h以内的雷暴天气有一定的指示意义,雷暴天气一般出现在垂直能量螺旋度大于0.62×10-5J·m·kg-1·s-2的条件下。