1. Use of AWS at MeteoSwiss: Experiences and Perspectives Thomas Frei, MeteoSwiss, 8044 Zürich, Switzerland

2. 1 st generation of automatic weather stations Problems nowadays: Problems nowadays: - New demands by data users - Difficulties by replacing instruments - IT – Infrastructure must be updated - Certain stations must be replaced (either because of the user or because of the land owner)

3. 1 st generation of automatic weather stations

4. Procedures for the introduction of the 2 nd generation of AWS 1.User requirements – technology free 2.Critical review, cost-benefit approach 3.Statement of guidance 4.Implementation plan

5. Data user‘s needs Governmental organisations Governmental organisations Universities Universities Private meteo agencies Private meteo agencies National weather service (including climatological unit) National weather service (including climatological unit)

6. Definition of different weather stations according to user requirements WESTA S2 for Synoptics WESTA S1 for Warning, Modell Input WESTA B(asis) for Synoptics, Climatology, Warning, Modell Input

7. Parameter WESTA B WESTA S1 WESTA S2 Ground Temp. X LuminosityX PressureXX Snow height X Air Temp. 2m XXX Air Temp. 5cm X List of parameters (examples) measured at the different station types

8. The new ground based AWS network in Switzerland

9. General data flow Sensors Data Logger Communication Network Central Data Acquisition System Network and Instrument Monitoring and Data analysing System Message Handling System Data Warehouse

10. Challenges for the future Demands by users change fast Demands by users change fast Technology concerning the sensors increases fast  Longtime support is not guaranted Technology concerning the sensors increases fast  Longtime support is not guaranted IT – lifecycle becomes shorter IT – lifecycle becomes shorter Land owner are less cooperative in terms of long-planning Land owner are less cooperative in terms of long-planning

11. Quality control and assurance

12. Comparison of 1 st versus 2 nd generation of AWS 1 st generation of AWS 1 st generation of AWS Only one type of weather stations (ANETZ) Only one type of weather stations (ANETZ) All needs must be satisfied by one type of AWS All needs must be satisfied by one type of AWS A lot of own research and development was necessary A lot of own research and development was necessary Several companies were involved for Logger, CDAS Several companies were involved for Logger, CDAS Human observation at the same spot as AWS Human observation at the same spot as AWS 2 nd generation of AWS 2 nd generation of AWS Three types of weather stations are defined (B, S1, S2) Three types of weather stations are defined (B, S1, S2) Climatological needs are satisfied for example mainly by B-stations Climatological needs are satisfied for example mainly by B-stations ADAS, CDAS, NIMDAS are bought from the market ADAS, CDAS, NIMDAS are bought from the market Only two companies are involved (except sensors) Only two companies are involved (except sensors) Human observation independent from AWS Human observation independent from AWS

13. Implementation for the 2 nd generation of AWS in Switzerland

14. Special thanks to: Dr. Alain Heimo, MeteoSwiss, Payerne Dr. Thomas Konzelmann, MeteoSwiss, Zürich Dr. Catherine Stocker, MeteoSwiss, Zürich