Contents 3 President’s Column 25 AW11 Provides Olympic Weather Reporting 4 New Calibration Procedure Optimizes RS90 Radiosonde 25 Sustainable Development Requires Performance Greater Understanding of Global Climate Systems 7 CAL4 Ensures Accurate Radiosonde Calibration 27 The 78th AMS Meeting: To maintain its high safety standards, Volvo Maturing Our Predictive Capability has extensive facilities for testing new models. 8 Promising Pilot Test Results of the Vaisala’s weather monitoring equipment New RS90 Radiosonde in Vienna 29 Vaisala’s Global ICE Activities informs test drivers about the ambient weath- er conditions. 11 New AUTOSONDE Installations in 30 New Predictive Road Condition Australia Monitoring for Flanders 12 JMA Upgrades Three ASAP 32 Finland’s Traffic Management Centre Sounding Systems 34 Ice Warning System Improves Traffic 13 MAWS – Automatic Weather Safety in Moscow Stations 36 Latvia Expands Its Road Weather 15 Important Step Towards Open Information System Communication 37 Ice and Fog Warning Systems in 16 Ambitious Upgrading Project in Australia Hungary 38 New Ice Prediction System for the Three new AUTOSONDEs were installed 20 Volvo’s Proving Ground: Birmingham Airport in Australia last year; one of them is situated Safety on the Tracks in the desert-like Cobar region. 40 The World’s Southernmost IceCast 22 MILOS 500 Data Collection System Installation Supports Marine Research 43 New ICE Customers Using information 23 A Vital Tool for Fire and Rescue 43 Key Personnel in the ICE Group provided by Vaisala’s Operations IceCast ice prediction system and extensive Thermal Mapping, the Birmingham Airport takes preven- tive action to avoid ice formation on criti- cal runway surfaces. Vaisala in Brief Cover photo: Design and Artwork: Lehtikuva/Sipa Image Non-Stop Studiot Oy Editor-in-Chief: Editors: Marit Finne Axioma Oy Publisher: Printed in Finland by Vaisala Oyj, P.O. Box 26 Sävypaino, Finland FI-00421 Helsinki, – We develop, manufacture and market – We focus on market segments where we FINLAND products and services for environmental can be world leaders, as the preferred sup- Phone (int.): and similar industrial measurements. plier. We pay high attention on customer (+358 9) 894 91 – Purpose of those measurements is to pro- satisfaction. Our main market quality disci- Telefax: vide basis for better quality of life, cost sav- pline is Product Leadership. Competitive (+358 9) 894 9227 ings, protection of environment, improved advantage is enhanced by economies of safety and performance. scale and scope. Internet: http://www.vaisala.com ISSN 1238-2388 2 147/19 9 8 ■ ■ ■ President’s Column ■ ■ ■ Setting New Standards hen people develop sensors in the RS90 radiosonde are now used in many locations something new – are new. The accuracy of tem- in both the Northern and either procedures or perature measurements has Southern hemispheres. The im- W products – there are been improved significantly, plementation of these systems usually three common themes: humidity measurements revive has created new models for simplification, automation and quickly after exposure to icy winter maintenance. Wherever integration. The same is true conditions, and the pressure they are used, these systems set for weather observations. Vai- sensor maintains its accurate a new standard for operations. sala has always looked boldly calibration even in harsh envi- A new standard is also need- to the future, aiming to create ronments. To optimize the per- ed for the quality of the global new products that offer added formance of these sensors and weather observation network. value to our customers. Instead achieve the greatest benefit To improve our understanding of simply comparing one prod- from them, we have integrated of climate variation and uct to another, we look at mar- completely new calibration changes, we have to build even ket needs from a wider perspec- equipment in our radiosonde better models of climate behav- tive. production. This was a major ior. This requires input from Today, full automation of challenge because we set much research, and correspondingly, upper air observations is a fact higher demands than those for better weather observations in of life. As the many operative traditional weather chambers. terms of geographical coverage, AUTOSONDE systems have Mini Automatic Weather time and measurement param- proved, our concept is reliable Stations (MAWS) represent a eters. The financial input need- and efficient. This technology new way of thinking about ed for continuous develop- has set a new standard for our weather station structure. The ment must be impressed on the vision of the observation net- compact design and easy con- national authorities, who should work in the next millennium. figuration of the MAWS are also be involved in the devel- Radiosonde product genera- brand new. Although most opment of the new standard. tions seldom change. New prod- applications are in the opera- ucts must represent significant tive weather services field, the advances before it is worth- MAWS will no doubt find while to verify their perfor- users in new applications re- mance. After years of research quiring real-time weather meas- and development work, we are urements. now launching a new-genera- Road and airport runway sys- Pekka Ketonen tion RS90 radiosonde. All the tems for ice and fog warning President and CEO 147/19 9 8 3 The structure of the CAL4 calibration machine. New Calibration Procedure Optimizes RS90 Radiosonde Performance When development of the new-generation RS90 The CAL4 has four pressure chambers with constant tempera- radiosonde began, the decision was made to ture and variable air pressure. optimize the calibration process and equipment The nominal temperatures are used with it. The goal was to take full advantage +60, +25, -33, and -72 °C. The of the advanced features of the entirely new pres- RS90 pressure sensors are cali- brated at nominal pressure lev- sure, temperature and humidity sensor of the els of 1080, 900, 800, 600, 400, new radiosonde. The following article describes 200, 100, 50, 20 and 2 hPa. Vaisala’s state-of-the-art calibration process for A fifth order polynomial pres- radiosonde sensors. It also discusses the factors sure calibration curve is fitted to Ari Paukkunen, Ph. Lic. (Phys.) ten pressure calibration points at Project Manager affecting the uncertainty of radiosonde measure- +25 °C. The temperature de- Upper Air Division ments. All the information included is based on pendence is calculated as the Vaisala Helsinki, Finland the texts cited in the references. deviation from the +25 °C cali- bration. The CAL4 has seven cham- bers dedicated to temperature calibration. The RS90 tempera- ture sensors are calibrated at aisala’s new CAL4 • Individual calibration of temperature levels of -90, -72, radiosonde calibra- each sensor with sensor -52, -33, -6, +25, and +60 °C. tion equipment was electronics The fifth order polynomial is fit- V specifically designed • Accurate and unbiased ted to the seven temperature cali- for the RS90 radiosonde. The mathematical modeling of bration points. The RS90 hu- result is a state-of-the-art calibra- the sensors midity sensors are calibrated at a ° tion system that meets the high- • Stable and well character- temperature of +25 C in four est performance standards, ized calibration chambers chambers at nominal humidities offering high accuracy with low of 0, 30, 60 and 90% RH. The short-term and long-term uncer- • Internationally traceable second order polynomial is fit- low uncertainty working tainties. In the development references and instruments ted through these four measure- process, the following require- ment points. The temperature ments for a good industrial cali- • Computer aided test (CAT) dependence correction is done bration system were carefully instrument set-up and checked in a chamber with a considered: • High level of automation nominal temperature of -33 °C. 4 147/19 9 8 1 Belongs organizationally to the Technical Research Centre of Finland. 2 Belongs organizationally to the Center for Metrology and Accreditation. points in the range of ±3 °C The measurement uncertain- The measurement uncertain- about the chamber nominal tem- ties of absolute pressure (k = 2) ty and dewpoint range covered perature. The thermistors are cali- and the ranges covered with with these instruments is as fol- brated at MSL at 6 month in- these instruments are as follows: lows: tervals. A set of dewpoint meters is • ±2% of reading from 0.1 to • 0.24 °C from -74 to +20 °C used as a working reference for 20 Pa, with MKS SRG-2 with GE 1311-DR/SR sen- humidity. The dewpoint meters Spinning Rotor Gage, sor are calibrated at MSL at 12 ° ° month intervals. The calibration • 0.5% of reading from 20 to • 0.22 C from 0 to +80 C of reference thermistors is de- 50 hPa, with MKS-Baratron with GE DR-2 sensor. scribed above. The reference Absolute Pressure Temperature dependence was value – expressed as relative hu- Transducer, Short-term and long-term uncertainty of CAL4 tested to be unlinear as a func- midity (over water) – is calculat- • (0.005% of reading + 0.08 tion of temperature accurately ed using the reference dewpoint Pa) from 50 hPa to 130 kPa, and accurately enough linear as a reading and the chamber tem- with Ruska-2465 Pressure The calculation of the shorst- function of humidity. perature by using Wexler and Balance. term uncertainty of CAL4 ( r) Hyland formulations for satura- is based on the following esti- References for tion vapour pressures (ref. 5 and The primary standards for tem- mations: radiosonde calibration 6). The long-term stability of the perature are the Hart 1575 Ther- humidity references is measured mometer and Hart 5681 Stand- • Uncertainty of the primary The quality of CAL4 calibra- by using the measured equiva- ard Platinum Resistance Ther- standard (chapter of tions is controlled by repeating lent water temperature of the air mometer. The Hart 1575 Ther- Traceability and uncertainty the calibration of a test sample saturator.