4.2
The Helsinki Testbed Program: An integrated atmospheric observing and modeling system
David M. Schultz, University of Helsinki and Finnish Meteorological Institute, Helsinki, Finland; and W. F. Dabberdt, J. Damski, E. Gregow, J. Koskinen, J. Poutiainen, R. Pyle, and H. Turtiainen
Since January 2005, the Finnish Meteorological Institute and Vaisala Corporation have established and maintained a mesoscale atmospheric observational network in southern Finland. The Helsinki Testbed (HTB) is a research and operational program designed to provide new information on observing systems and strategies, mesoscale weather phenomena, urban and regional modeling, and applications in a high-latitude coastal environment. As the HTB enters its fourth year of operations and a second phase of funding, this paper provides an update on the activities and research programs of the HTB.
The HTB program features several components: observing system design and implementation, small-scale data assimilation and short-range numerical weather prediction, public service, and commercial development of applications. Examples of each of these components are described below.
THE OBSERVING SYSTEM: The HTB focuses on meteorological observations and forecasting directed towards meso-gamma-scale phenomena that are often too small to be detected adequately by traditional observing networks. The domain of the HTB covers much of southern Finland and the Gulf of Finland. Most of the new observation sites are located in an area of about 150 x 150 km that includes Helsinki. In particular, more than 40 communication masts, 60–100-m high, are equipped with new weather transmitters capable of measuring temperature, humidity, air pressure, rain, and wind speed and direction. Each mast has at least two measurement heights, typically 2 m and mast top. Additionally, the number of radio soundings and ceilometer measurements has been increased, a wind profiler and dual-polarimetric radar have been installed, and data from five satellites and four Doppler weather radars are available. Most of the data is freely available on the Internet, and the HTB is an open program, which means collaborative and independent measurements are encouraged. The Helsinki Testbed supports the development and testing of new observational instruments, systems and methods in concentrated field experiments. The first live tests of the HTB took place in August 2005, and provided real-time support to the World Championships in Athletics. Measurements were accomplished through five thematic, typically month-long, measurement campaigns. During these campaigns, the existing Finnish weather observation network was supplemented with a number of new in situ and remote sensing observations. NASA is considering Helsinki Testbed to be one of the major calibration and validation sites for the Global Precipitation Mission (GPM) planned to be launched in 2013. Helsinki Testbed will also serve the GPM mission, especially, in development of retrieval algotihms for winter precipitation.
DATA ASSIMILATION AND NUMERICAL WEATHER PREDICTION: The heart of the data assimilation and forecast system is Local Analysis and Prediction System (LAPS) developed by NOAA Earth Systems Research Laboratory's Global Systems Division. Although LAPS presently can be run operationally using the HTB data, much work remains to determine the optimal configuration (e.g., domain, resolution, use of ensembles, sensitivity to assimilation parameters) to provide the best analysis and forecasts. A research program to explore the sensitivities of the LAPS configuration to the performance of the analyses and forecasts is presently being developed. The results of this program will immediately benefit the LAPS implementation using the HTB, but will inform future commercial users of the HTB, as well as the data assimilation and numerical weather prediction communities.
PUBLIC SERVICE: Data from the HTB is freely available on the FMI web site. A recent two-month survey of 462 users shows that a majority of people are using it for personal reasons, citing a need for weather information for recreation, commuting, or home improvement, among others. Some people like access to weather data closer to where they live or work. Forty-four percent of respondents have already recommended it to others. Some other Finnish cities (e.g., Kokkola, Oulu) have implemented testbeds, too, recognizing the potential benefit to the public.
APPLICATIONS: Applications being developed using the HTB data include those for air quality and road weather. Air-quality applications will involve the following tasks: the short-term chemical dispersion forecast and real-time assessment services for emergency response and odor prevention; the development of a new generation of pollution dispersion models using high-resolution meteorology; development and testing of methods directly using the dense meteorological observation network, especially the meteorological profile measurements, for providing the essential turbulence characteristics and mixing height estimates needed for air-quality models; and near-real-time analysis of the size distribution and chemical composition of the ambient fine particles. The evolution of the sea breeze plays an important role in the dispersion of atmospheric constituents. The Helsinki capital area offers a representative study region for urban air quality research and boundary-layer modeling, especially in stable nocturnal conditions, which are dominant in the area (especially in winter when stable stratification can exist throughout the day). Road-weather applications will provide more precise weather information in time and space to develop new type of intelligent road weather services, including applications based on the numerical weather prediction efforts. The key idea of intelligent road-weather services is, not only to provide pure road weather information, but also refine the information for the customers' own needs. Different modules will be constructed on general platforms, allowing for easy commercialization. Also, FMI will provide a new type of road weather services for private users using the latest mobile phone and internet technologies.
All interested users are welcome to use the data or to implement additional observational, modeling or application tools. Guidance and data policies are provided at the HTB website http://testbed.fmi.fi.
Recorded presentationSession 4, Atmospheric Observations for Weather and Climate-IV
Monday, 21 January 2008, 4:00 PM-5:30 PM, 204
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