1、BSI Standards PublicationBS ISO 19289:2015Air quality Meteorology Siting classifications for surfaceobserving stations on landBS ISO 19289:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19289:2015. The UK participation in its preparation was entrusted to
2、TechnicalCommittee EH/2/3, Ambient atmospheres.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Sta
3、ndards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 83778 4 ICS 07.060 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2015.Am
4、endments/corrigenda issued since publicationDate T e x t a f f e c t e d ISO 2015Air quality Meteorology Siting classifications for surface observing stations on landQualit de lair Mtorologie Classifications des sites pour les stations terrestres dobservationINTERNATIONAL STANDARDISO 19289First edit
5、ion 2015-03-01Reference number ISO 19289:2015(E)BS ISO 19289:2015ISO 19289:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, elec
6、tronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. +
7、41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 19289:2015ISO 19289:2015(E)Foreword ivIntroduction v1 Scope . 12 Air temperature and humidity . 12.1 General . 12.2 Class 1 . 22.3 Class 2 . 32.4 Class 3 (additional estimated uncertainty added b
8、y siting up to 1 C) 32.5 Class 4 (additional estimated uncertainty added by siting up to 2 C) 42.6 Class 5 (additional estimated uncertainty added by siting up to 5 C) 43 Precipitation . 53.1 General . 53.2 Class 1 . 53.3 Class 2 (additional estimated uncertainty added by siting up to 5 %) 63.4 Clas
9、s 3 (additional estimated uncertainty added by siting up to 15 %) .63.5 Class 4 (additional estimated uncertainty added by siting up to 25 %) .63.6 Class 5 (additional estimated uncertainty added by siting up to 100 %) 74 Surface wind 74.1 General . 74.2 Roughness . 74.3 Environment classification .
10、 84.4 Class 1 . 84.5 Class 2 (additional estimated uncertainty added by siting up to 30 %, possibility to apply correction) . 94.6 Class 3 (additional estimated uncertainty added by siting up to 50 %, correction cannot be applied) . 94.7 Class 4 (additional estimated uncertainty added by siting grea
11、ter than 50 %) 104.8 Class 5 (additional estimated uncertainty cannot be defined) 105 Global and diffuse radiation 105.1 General 105.2 Class 1 105.3 Class 2 115.4 Class 3 115.5 Class 4 115.6 Class 5 126 Direct radiation and sunshine duration .126.1 General 126.2 Class 1 126.3 Class 2 126.4 Class 3 1
12、36.5 Class 4 136.6 Class 5 13Bibliography .14 ISO 2015 All rights reserved iiiContents PageBS ISO 19289:2015ISO 19289:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internationa
13、l Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO,
14、also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1
15、. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the ele
16、ments of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations receiv
17、ed (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adhe
18、rence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationISO 19289 was prepared by ISO/TC 146, Air quality, Subcommittee SC 5, Meteorology, and the World Meteorological Organization (WMO) as a common ISO/WMO Standard under the Ag
19、reement on Working Arrangements signed between the WMO and ISO in 2008. This International Standard is identical to the “Siting Classifications for Surface Observing Stations on Land”, published in the WMO Guide to Meteorological Instruments and Methods of Observations (WMO-No. 8), 2014 Edition, Par
20、t I, Chapter 1, Annex 1B.iv ISO 2015 All rights reservedBS ISO 19289:2015ISO 19289:2015(E)IntroductionEnvironmental conditions of a site1)might influence the measurement results. A careful analysis of the site environmental conditions is to be associated to the knowledge of the instrument characteri
21、stics to avoid quantities of influence to distort measurement results affecting their representativeness, particularly when a site is supposed to be representative of a large area (i.e. 100 km2to 1 000 km2).1) A “site” is defined as the place where the instrument is installed. ISO 2015 All rights re
22、served vBS ISO 19289:2015BS ISO 19289:2015Air quality Meteorology Siting classifications for surface observing stations on land1 ScopeThis International Standard indicates exposure rules for various sensors, but what should be done when these conditions are not fulfilled? There are sites that do not
23、 respect the recommended exposure rules. Consequently, a classification has been established to help determine the given sites representativeness on a small scale (impact of the surrounding environment). Hence, a class 1 site can be considered as a reference site. A class 5 site is a site where near
24、by obstacles create an inappropriate environment for a meteorological measurement that is intended to be representative of a wide area (at least tens of km2). The smaller the siting class, the higher the representativeness of the measurement for a wide area. In a perfect world, all sites would be in
25、 class 1 but the real world is not perfect and some compromises are necessary. A site with a poor class number (large number) can still be valuable for a specific application needing a measurement in this particular site, including its local obstacles.The classification process helps the actors and
26、managers of a network to better take into consideration the exposure rules and thus it often improves the siting. At least, the siting environment is known and documented in the metadata. It is obviously possible and recommended to fully document the site but the risk is that a fully documented site
27、 might increase the complexity of the metadata, which would often restrict their operational use. That is why this siting classification is defined to condense the information and facilitate the operational use of this metadata information.A site as a whole has no single classification number. Each
28、parameter being measured at a site has its own class and is sometimes different from the others. If a global classification of a site is required, the maximum value of the parameters classes can be used. The rating of each site should be reviewed periodically as environmental circumstances can chang
29、e over a period of time. A systematic yearly visual check is recommended: if some aspects of the environment have changed, a new classification process is necessary. A complete update of the site classes should be done at least every five years.In this International Standard, the classification is (
30、occasionally) completed with an estimated uncertainty due to siting, which has to be added in the uncertainty budget of the measurement. This estimation is coming from bibliographic studies and/or some comparative tests.The primary objective of this classification is to document the presence of obst
31、acles close to the measurement site. Therefore, natural relief of the landscape may not be taken into account, if far away (i.e. 1 km). A method to judge if the relief is representative of the surrounding area is the following: Does a move of the station by 500 m change the class obtained? If the an
32、swer is no, the relief is a natural characteristic of the area and is not taken into account.Complex terrain or urban areas generally lead to high class numbers. In such cases, an additional flag “S” can be added to class numbers 4 or 5 to indicate specific environment or application (i.e. 4S).2 Air
33、 temperature and humidity2.1 GeneralSensors situated inside a screen should be mounted at a height determined by the meteorological service (within 1,25 m to 2,0 m as indicated in Reference 1). The height should never be less than 1,25 m. The respect of the higher limit is less stringent, as the tem
34、perature gradient versus height is decreasing with height. For example, the difference in temperature for sensors located between 1,5 m and 2,0 m is less than 0,2 C.INTERNATIONAL STANDARD ISO 19289:2015(E) ISO 2015 All rights reserved 1BS ISO 19289:2015ISO 19289:2015(E)The main discrepancies are cau
35、sed by the following unnatural surfaces and shading:a) Obstacles around the screen influence the irradiative balance of the screen. A screen close to a vertical obstacle might be shaded from the solar radiation or “protected” against the night radiative cooling of the air by receiving the warmer inf
36、rared radiation from this obstacle or influenced by reflected radiation;b) Neighbouring artificial surfaces might heat the air and should be avoided. The extent of their influence depends on the wind conditions, as wind affects the extent of air exchange. Unnatural or artificial surfaces to take int
37、o account are heat sources, reflective surfaces (for example, buildings, concrete surfaces, car parks), and water or moisture sources (for example, ponds, lakes, irrigated areas). Shading by nearby obstacles should be avoided. Shading due to natural relief is not taken into account for the classific
38、ation (see above). The indicated vegetation growth height represents the height of the vegetation maintained in a “routine” manner. A distinction is made between structural vegetation height (per type of vegetation present on the site) and height resulting from poor maintenance. Classification of th
39、e given site is therefore made on the assumption of regular maintenance (unless such maintenance is not practicable).2.2 Class 1a) Flat, horizontal land, surrounded by an open space, slope less than 1/3 (19);b) Ground covered with natural and low vegetation (30);b) Possible obstacles shall be situat
40、ed at a distance greater than one half (1/2) the height of the obstacle.6 ISO 2015 All rights reservedBS ISO 19289:2015ISO 19289:2015(E)Key1 siteFigure 8 Schematic showing criteria for precipitation for class 4 sites3.6 Class 5 (additional estimated uncertainty added by siting up to 100 %)Obstacles
41、situated closer than one half (1/2) their height (tree, roof, wall, etc.).Figure 9 Schematic showing criteria for precipitation for class 5 sites4 Surface wind4.1 GeneralConventional elevation rules stipulate that sensors should be placed 10 m above ground surface level and on open ground. Open grou
42、nd here represents a surface where obstacles are situated at a minimum distance equal to at least 10 times their height.4.2 RoughnessWind measurements are disturbed not only by surrounding obstacles; terrain roughness also plays a role.WMO defines wind blowing at a geometrical height of 10 m and wit
43、h a roughness length of 0,03 m as the surface wind for land stations.This is regarded as a reference wind for which exact conditions are known (10 m height and roughness length of 0,03 m).Therefore, roughness around the measuring site has to be documented. Roughness should be used to convert the mea
44、suring wind to the reference wind but this procedure can be applied only when the obstacles are not too close. Roughness-related matters and correction procedure are described in Reference 1(Part I, Chapter 5). ISO 2015 All rights reserved 7BS ISO 19289:2015ISO 19289:2015(E)The roughness classificat
45、ion reproduced from Reference 1(Part I, Chapter 5) is recalled here:Table 1 Terrain classification 2,3in terms of aerodynamic roughness length z0Class index Short terrain descriptionz0in m1 Open sea, fetch at least 5 km 0,000 22 Mud flats, snow; no vegetation, no obstacles 0,0053 Open flat terrain;
46、grass, few isolated obstacles 0,034 Low crops; occasional large obstacles, xH 20 a0,105 High crops; scattered obstacles, 15 8 mKeyaWidth.Figure 10 Schematic showing criteria for surface wind for class 1 sites4.5 Class 2 (additional estimated uncertainty added by siting up to 30 %, possibility to app
47、ly correction)a) The mast should be located at a distance of at least 10 times the height of the surrounding obstacles;b) Sensors should be situated at a minimum distance of 15 times the width of thin obstacles (mast, thin tree) over 8 m high.Single obstacles lower than 4 m can be ignored.Roughness
48、class index is less than or equal to five (roughness length 0,25 m).a) Location of mast b) Large obstacle c) Thin obstacle 8 mKeyaWidth.Figure 11 Schematic showing criteria for surface wind for class 2 sitesNOTE When the mast is located at a distance of at least 20 times the height of the surroundin
49、g obstacles, a correction see Reference 1(Part I, Chapter 5) can be applied. In case of nearer obstacles, a correction may be applied in some situations.4.6 Class 3 (additional estimated uncertainty added by siting up to 50 %, correction cannot be applied)a) The mast should be located at a distance of at least five times the height of surrounding obstacles; ISO 2015 All rights reserved 9BS ISO 19289:2015ISO 19289:2015(E)b) Sensors should be situated at a minimum distance of 10 times the width of thin obstacl
