Manual on Instrumentation and Operations for Automatic Weather Stations for Agrometeorological Application
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World Meteorological Organization Institute ofAgrometeorology and Environmental Analysis for Agriculture - Research National Council Regional Meteorological Training Center Manual on Instrumentation and Operations for Automatic Weather Stations for Agrometeorological Application P. Battista, G. Maracchi, F. Sabatini, M.V.K. Sivakumar, A. Zaldei { 1 [ { i I I ! I t L Manual on Instrumentation and Operations for Automatic Weather Stations for Agrometeorological Application P. Battista Ce.S.LA - Center for Computer Science in Agriculture - Georgofili Academy, Via G. Caproni, 8 - 50145 Florence, Italy. G. Maracchi LAT.A - C.N.R. - Institute of Agrometeorology and Environmental Analysis for Agriculture - Research National Council- P.le delle Cascine, 18 - 50144 Florence, Italy. F. Sabatini LAT.A - C.N.R. - Institute of Agrometeorology and Environmental Analysis for Agriculture - Research National Council- P.le delle Cascine, 18 - 50144 Florence, Italy. M.V.K. Sivakumar World Meteorological Organization - Agricultural Meteorology Division - 41 Avenue Giuseppe Motta - 1211 Geneva 2 - Switzerland A. Zaldei AM.F. - Applied Meteorological Foundation - Via G. Caproni, 8 - 50145 Florence, Italy. This document was prepared to education plllpose, with examples and exercises, using trademarked names and symbols. This is due to the necessity of explain technical operations and it doesn't implicate any preference by the authors. r f' 1-' r t' 1~ J L t f [ f f 1 f f L Index - Introduction MANUAL ON INSTRUMENTATION AND OPERATIONS FOR AUTOMATIC WEATHER STATIONS FOR AGROMETEOROLOGICAL APPLICATIONS r~ i-' I I f' I { I I t [ t I I f I I { 1 L Index - Introduction - INTRODUCTION - 1) SENSORS 1.1 ) Temperature 1.1.1) Thermocouples 1.1.2) Thermistors 1.1.3) Thermoresistances 1.1.4) Integrated sensors 1.1.5) Linearized Thermistors 1.2) Air Humidity 1.2.1) Hygrometric sensors 1.2.2) Psycrometric sensors 1.2.3) Dew-point sensors 1.3) Soil Humidity 1.3.1) Neutron Probe 1.3.2) Bouyoucos probes 1.3.3) Tensiometers 1.3.4) Time Domain Reflectometry (TDR) 1.4) Air Pressure 1.4.1) Capacity sensors 1.4.2) Inductivity sensors 1.4.3) Piezoelectric sensors 1.4.4) Potentiometetric sensors 1.4.5) Resistivity sensors 1.4.6) Semicondutor sensors 1.5) Solar Radiation 1.5.1) Thermopile 1.5.2) Photocell 1.6) Wind Speed 1.6.1) Cup Anemometer 1.6.2) Hot wire Anemometer 1.6.3) Ultrasonic Anemometer 1.6.4) Doppler Anemometer 1.7) Wind direction 1.8) Rainfall 1.8.1) Pluviometer 1.8.2) Meteorological Radar 1.8.3) Rain drop energy sensor (Impactometer) 1.9) Evaporation 1.9.1) Evaporimeters 1.9.2) Lysimeters 1.10) Leafwetness 1.11) Soil heat flux 2) DATA ACQUISITION SYSTEMS 2.1) Data-Logger Index - Introduction 2.2) Data-Logger programming 2.3) Data storage 2.3.1) Solid state memory 2.3.2) PC card 2.3.3) Magnetic tape 2.3.4) Hard disk 2.4) Data retrieval 2.4.1) Personal Computer cOlmection 2.4.2) Memory card 2.4.3) Remote Transmission ofdata 2.4.3.1) Radio 2.4.3.2) Modem 2.4.3.2.1) Dedicated or commutated phone line 2.4.3.2.2) Cellular phones 2.4.3.2.3.) Satellite 3) STATE OF THE ART AND AVAILABLE INSTRUMENTATION 3.1) Data-logger 3.2) Sensors J.J'1 '1) Integrated logger and transducer systems 3.4) Low-cost agrometeorological station ofC.N.R.-LA.T.A. 3.4.1) Data-logger 3.4.2) Sensors 4) UTILIZATION AND MAINTENANCE OF AUTOMATIC AGROMETEOROLOGICAL STATIONS 4.1) Agrometeorological station location 4.2) Sensors employment 4.2.1) Air temperature 4.2.2) Soil temperature 4.2.3) Air humidity 4.2.4) Soil humidity 4.2.5) Air pressure 4.2.6) Solar radiation 4.2.6.1) Global Radiation 4.2.6.2) Diffuse radiation 4.2.6.3) Direct radiation 4.2.6.4) Outgoing radiation 4.2.6.5) Net radiation 4.2.6.6) Photosynthetically Active Radiation (P.A.R.) 4.2.6.7) Sunshine duration 4.2.6.8) UV-B radiation 4.2.7) Wind speed 4.2.8) Wind direction 4.2.9) Rainfall 4.2.10) Evaporation 4.2.11) Leafwetness 4.2.12) Heat flux plate I L Index - Introduction 5) INSTRUMENTATION POWER SUPPLY AND PROTECTION 5.l) Power supply 5.1.1) Main power supply - No-break power 5.1.2) Battery power supply - Solar panel 5.2) Instrument protection 5.2.1) Environmental class quality 5.2.2) Over-transient voltage protection 6) SENSORS CALIBRATION 6.1) Calibration principles 6.1.1) Sensors comparison calibration 6.1.2) Calibration uncertainty 6.1.3) Methodology 6.1.4) Calibration response curve 6.1.5) Time response 6.2) Sensors calibration 6.2.1) Air temperature 6.2.2) Air humidity 6.2.3) Air pressure 6.2.4) Solar radiation 6.2.5) Wind speed 6.2.6) Rainfall 6.2.7) Evaporation 6.2.8) Heat Flux Plate 7) DATA ANALYSIS AND ARCHIVING 7.1) Data validation 7.1.1) Values range check and time-based verification 7.1.2) Historical data series comparison (statistical method) 7.2) Data process 7.2.1) Time unit (hour, day, decade, month, year. .. ) 7.2.2) Data processing choice 7.2.3) Agroclimatologica1 processing 7.2.4) Data visualization 3.2.4.1) Graphic display 3.2.4.2) Numeric (data table) 7.3) Data format 7.3.1) Binary 7.3.2) Hexadecimal 7.3.3) ASCII format 7.3.4) Commercial and specific software data storage 7.4) Data diffusion 7.4. 1) Weather rep0 rt 7.4.2) Telefax 7.4.3) Television 7.4.4) Internet Index - Introduction r f' 8) EXAMPLES OF INSTALLATIONS FOR SPECIFIC PURPOSES 8.1) Dimensioning of solar panel power for agrometeorological station l' 8.2) Installation for air temperature profile study 8.3) Installation for wind erosion study 8.4) Installation for crop water irrigation scheduling r 8.5) Installation for crop protection strategy based on agrometeorological data 8.6) Installation for UV-B radiation study f' I 9) APPENDIX 9.1) Metrology characteristics ofinstruments r' 9.2) Instrument's employment features 9.3) Conversion tables for main measurements units 9.4) Institutions and Companies addresses of agrometeorological interest f' 9.5) Julian days table 9.6) Crop coefficients f 10) INTERNET USEFUL ADDRESSES f I { ( L f r 1 I I t L Index - Introduction - INTRODUCTION - Purposes of the Guide In the past twenty years the world of applied meteorology, climatology and environmental monitoring changed in a radical way. Experts trained in the knowledge and techniques and this process is already under way. The fields where the changes where more relevant are electronics, computer science, telecommunications, space science. Nowadays an applied meteorologist should deal with a large number of tools ranging from automatic weather stations to geographical information systems, from satellite pictures to information technologies as Internet. The ability to manage all these teclmiques together"and to apply them to the data collecting, archiving and processing according to a logic chain allows delivering to the users new products with a higher added value. At the same time the impact of man activities on the planet, the globalization of trades and policies, the huge increase of world population open new scenarios. Close to the preoccupations for the food availability and health situation of a large part of mankind there is now a new attention to the environmental impacts of many industrial practices and to the sustainability of some activities as agriculture, fisheries, forestry. The United States Conference of Rio de Janeiro and recently of Kyoto are the clear signal that there is a new political recognized dimension of the world social, economic and environmental strategies. In this perspective new areas of intervention as in the case of climatic impacts and climate prediction should give in the future fruitful results. All these aspects, technological and political ask for new capacities building at level both of scientists and of public services concerned with the natural resources management. This manual would be a modest contribution to the bringing technicians up to date and to give them some of the tools that should help to reply to new eXigenCies. Peace and welfare should come also from a common effort to manage to manage in a better way, scientifically based, our world and save at the same time traditions and cultures ofvarious communities! The plan of the guide is conceived to allow the user to plan, buy, install. maintain automatic weather stations jointly with the first data processing concerning data quality assessment, data organization and editing. Index - Introduction TIns guide should be usefully completed with the lecture of the Guide to Computer Science Application in Agrometeorology, of the same authors. In a time where in many parts of the world the evidence of climatic anomalies is under way, the importance of reliable observation is increasing. To the efforts of the W.M.O. and of the authors there is a need for an effort of the users to develop a new professionalism and to look around to a world that is rapidly changing!! { t Index - Introduction Note about the Manual At the end of each chapter there is a bibliography appendix. In the text a number in square brackets relates to the bibliography cited. In the text you could find also a word in square brackets. It relates to the Internet pages cited. In the chapter 10 there are the Internet addresses related to each chapter. r~ l' 1' ACF~OWLEDGEMENTS r The authors wish to thank all the staffofLA.T.A.