山西省日照平行观测资料对比分析

<正>1引言日照是指太阳在一地实际照射的时数。日照时数也称实照时数[1];其定义为,在一给定时间,太阳直接辐照度达到或超过120瓦·米^-2(W·m^-2)的那段时间总和,以小时(h)为单位,取一位小数。日照时数表示一个地区接受太阳光照射的时间长短,直观反映太阳辐射,是农业生产重要的环境因素,对人民的日常生活影响重大。日照时间的长短决定了对太阳能的利用程度,也对当地的气候资源具有较高的分析     

Comparison of models calculating the sky view factor used for urban climate investigations

The sky view factor (SVF) describes the surface geometry and is a commonly used and important measure in urban climate investigations whose aim is the exploration of effects of a complex urban surface on climatological processes in built-up areas. A selection of methods and models for calculating the SVF was compared. For this purpose, fish eye images were taken at several locations in the city of Szeged, southern Hungary. The fish eye images equidistantly follow linear transects to cover a range of SVF values and to analyze the reaction of the methods to a continuously changing environment. The fish eye pictures were evaluated by three methods: the method according to Steyn (Atmos-Ocean 18(3):245?C258, 1980) implemented in a GIS-Script, the ??Edit free sky view factor?? tool of the RayMan model and BMSkyView. The SVF values at the coordinates of the fish eye pictures were calculated with three numerical models (SkyHelios, ArcView SVF extension, and SOLWEIG) with a 3D building data base as input. After comparing the results of the first run, a deviation occurs. The deviation disappears after implementing an option to include a weighting factor in some of the models.     

The group of sunshine modes on any inclined surface

Summary It is easy to compute the diurnal arc or day length. We show that the same simplicity exists for the solar arc on an inclined surface, i.e. the theoretical interval during which it sees the sun. By transposing the daily extraterrestrial irradiance onto the celestial sphere, we demonstrate the concept of image, sunshine modes, transitions from one mode to another and annual sequence of modes which are, in a sense, the generalization of astronomical seasons for inclined surfaces. The modes are the elements of a group, or the focus of the theory. We give the foundation of a simple and exhaustive theory on the subject for any surface the following explicit formulae: image, mode, declination of transition between two modes, sunrise and sunset, solar arc or extraterrestrial sunshine, and daily irradiance. This subject has been previously broached in some infrequently referenced papers as well as in more recent papers by Revfeim (1976, 1978, 1982), Swift (1976), and Sato (1984). However, due to their lack of structure, those contributions to a geometrical theory have been largely neglected and the empirical point of view still prevails.With 2 Figures     

黔南州2019年人工与自动站日照数据对比分析

本文主要通过利用黔南州12市、县2019年自动站与人工的日照观测月整编数据从理论上分析黔南州自动站与人工日照观测数据之间的差异,结果表明：黔南州1-12月自动站观测的小时日照次数均高于人工观测到的次数;自动站观测的小时日照次数从1月起表现为明显、稳定的逐月上升趋势,并在在8月达到全年峰值;在观测小时日照时数时,人工与自动站的观测数值接近,误差小。总体来讲,光电式日照计比暗筒式日照计有着更好的感光能力,所以自动站的日照观测数据更为客观和准确,但二者之间的日照观测数值仍有着较强的相关性。     

基于MODIS数据的水体识别指数方法的比较研究

从典型地物光谱曲线分析入手,MODIS数据的第7、2、1波段对植被、陆地、水体区分明显。本文对长三角太湖流域地区,采用MODIS数据以五种常水体识别进行水体信息提取,然后分别从目视解译效果、水体区分度的计算和提取的水体面积三方面来对这五种指数方法进行比较和评价。结果表明,在应用MODIS数据进行水体识别时,比值植被指数（RVI,Ratio Vegetation Index）和混和水体指数（CIWI,Combined Index of Normalized Difference Water Index）模型的目视解译效果较好,且CIWI指数具有水陆区分度较大和水体面积提取精度较高的优点。     

On the positivity of mass in commonly used numerical transport schemes

Abstract

Numerical transport schemes used in atmospheric models only approximate the evolution of the real mass continuity equation. The inaccuracies introduced by discretization schemes result, amongst other things, in the appearance of fictitious “holes” in the mass field, i.e. places where the concentration is locally negative. In this article we compare the behaviour of various numerical schemes that are commonly used in atmospheric models, the remedies that are often applied to prevent the appearance of unphysical holes, and their side effects on the evolution of a transported field.     

内蒙古自动站与人工观测数据差异对比分析

利用2006年内蒙古自治区共36个自动站和人工站平行观测资料,对观测得到的气象要素进行了统计和评估。通过分析气温、气压、相对湿度、风等要素的对比差值及其标准差、对比差值的频次分布和空间分布等,探讨自动站与人工观测数据差异的可能原因。结果表明：内蒙古自动观测与人工观测各气象要素均存在一定的差异,对所有台站平均而言,其差异均在自动站差值允许范围之内。产生差异的原因：观测仪器结构与观测原理差异、观测时空差异、观测方式差异等,在将人工观测数据与自动观测数据连续使用时,需要根据当地情况进行适当订正,以确保资料的连续性。     

陕西降水现象仪与人工观测资料对比评估

利用陕西省99个地面气象观测站2018年1-12月降水现象仪观测记录和人工观测记录的平行资料,从数据完整性、准确性、一致性等方面进行全面分析评估,结果表明:陕西20站降水现象仪基本能满足业务需求,其余79站均需要延长平行观测时间。建议进一步完善仪器性能,优化相关数据处理软件。     

江西省闪电定位资料与人工观测雷暴日的对比分析

利用江西省81个气象站1984—2013年雷暴日观测资料和2010—2019年闪电定位资料,对比分析了3—19 km半径下闪电日数与雷暴日数的关系。结果表明,全省范围内闪电日数与雷暴日数相等的监测半径置信区间为10.1—11.5 km,监测半径为 10 km 和 11 km 时全省闪电日数与雷暴日数差异不显著,相对偏差最小。聚类分析表明,全省闪电日数与雷暴日数相等的半径可分为5个区域：R1—R5,对应闪电日数与雷暴日数相等的半径均值分别为14.5、9.4、9.6、10.5、10.2 km。     

使用AHDM程序常见问题及气表-1的人工审核

介绍黑龙江省在开展县 -省两级机制气表审核试点中 ,使用AHDM - 4 1程序审核时遇到的问题及解决办法 ,并介绍了人工审核的方法