GAW Report No. 227 WMO/GAW Aerosol Measurement Procedures, Guidelines and Recommendations 2nd Edition 2016 WEATHER CLIMATE WATER CLIMATE WEATHER WMO-No. 1177 GAW Report No. 227 WMO/GAW Aerosol Measurement Procedures, Guidelines and Recommendations 2nd Edition 2016 WMO-No. 1177 2016 THIS REPORT SUPERSEDES GAW REPORT No. 153 EDITORIAL NOTE METEOTERM, the WMO terminology database, may be consulted at: http://www.wmo.int/pages/prog/lsp/meteoterm_wmo_en.html. Acronyms may also be found at: http://www.wmo.int/pages/themes/acronyms/index_en.html. © World Meteorological Organization, 2016 The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chairperson, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 80 40 CH-1211 Geneva 2, Switzerland E-mail: [email protected] ISBN 978-92-63-11177-7 NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of itsfrontiers or boundaries. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. The findings, interpretations and conclusions expressed in WMO publications with named authors are those of the authors alone and do not necessarily reflect those of WMO or its Members. This publication has been issued without formal editing. CONTENTS Preface 1. INTRODUCTION ............................................................................................. 1 2. SAMPLING TECHNIQUES AND CONSIDERATIONS .......................................... 6 2.1 Inlet design considerations ......................................................................... 6 2.2 Size cuts-offs ........................................................................................... 7 2.3 Tubing and flow splitters ............................................................................ 8 2.4 Sample drying .......................................................................................... 9 2.5 General aspects of particle motion .............................................................. 9 2.5.1 Laminar flow sampling configuration .................................................. 10 2.5.2 Turbulent flow sampling configuration ................................................ 11 2.6 Integrated aerosol sampling and local contamination .................................... 13 2.7 Sampling system integrity ......................................................................... 13 References 3. AEROSOL CHEMICAL MEASUREMENTS AT GAW STATIONS ............................. 15 3.1 Introduction ............................................................................................. 15 3.2 Critical issues for a GAW station for aerosol chemical monitoring ..................... 15 3.3 Recommended chemical sampling techniques and analysis ............................. 15 3.3.1 Sampling media and methods ........................................................... 15 3.3.2 Sampling setup for aerosol chemical analysis ...................................... 17 3.3.3 Flow measurements ........................................................................ 17 3.3.4 Sampling frequency ........................................................................ 18 3.3.5 Recommended analyses and considerations ........................................ 18 3.3.5.1 Mass ................................................................................. 19 3.3.5.2 Ionic species in aerosols ....................................................... 20 3.3.5.3 Mineral dust ....................................................................... 22 3.3.5.4 Carbonaceous materials ....................................................... 23 3.3.5.5 Trace components ............................................................... 25 3.3.6 Location and distribution of analytical chemistry .................................. 26 3.4 Sample handling protocol .......................................................................... 26 3.5 Continuous instrumentation ....................................................................... 27 3.6 Quality assurance and quality control plans .................................................. 30 References 4. IN SITU MEASUREMENTS OF AEROSOL RADIATIVE PROPERTIES ................... 34 4.1 Introduction ............................................................................................. 34 4.2 Aerosol particle light scattering ................................................................... 35 4.3 Aerosol particle light absorption .................................................................. 37 4.4 Aerosol particle light extinction ................................................................... 41 4.5 Data reporting, sampling frequency, data editing .......................................... 41 4.6 Quality assurance and quality control considerations (QA/QC) ......................... 42 5. PARTICLE NUMBER CONCENTRATION AND SIZE DISTRIBUTION ................... 46 5.1 Particle number concentration .................................................................... 46 5.1.1 Condensation particle counter ........................................................... 46 5.1.2 Calibration ..................................................................................... 47 5.1.3 Network measurement .................................................................... 47 5.2 Particle number size distribution ................................................................. 48 5.2.1 Mobility particle size spectrometer ..................................................... 48 5.2.1.1 Recommended instrument set-up .......................................... 48 5.2.1.2 Recommended particle loss correction .................................... 51 5.2.1.3 Operation procedures and calibrations .................................... 52 References 6. CLOUD CONDENSATION NUCLEI .................................................................... 56 6.1 Introduction ............................................................................................. 56 6.2 Instrument operation ................................................................................ 56 6.3 Data collection and processing .................................................................... 57 6.4 Instrument maintenance ............................................................................ 58 References 7. AEROSOL OPTICAL DEPTH ............................................................................. 60 7.1 Introduction ............................................................................................. 60 7.2 Method of measurement ............................................................................ 61 7.2.1 Wavelengths and field of view ........................................................... 61 7.2.2 Sampling strategy ........................................................................... 61 7.2.3 Ancillary measurements ................................................................... 62 7.3 Instrumentation ....................................................................................... 62 7.4 Calibration issues ..................................................................................... 63 7.5 Data evaluation ........................................................................................ 63 7.6 Quality control and assurance ..................................................................... 64 7.7 Reporting interval ..................................................................................... 65 References 8. GAW AEROSOL LIDAR .................................................................................... 68 8.1 Introduction ............................................................................................. 68 8.2 Lidar remote sensing ................................................................................. 68 8.3 Aerosol lidar techniques ............................................................................. 69 8.4 Lidar aerosol products ............................................................................... 70 8.5 Specifications ........................................................................................... 72 8.6 Quality assurance and quality control plans .................................................. 73 References 9. ARCHIVING PROCEDURES ............................................................................. 77 9.1 Introduction ............................................................................................. 77 9.2 WDCA architecture .................................................................................... 78 9.3 Implementation of data traceability ............................................................. 79 9.4 Submitting Data to the World Data Centre for Aerosol .................................