The Helsinki Testbed: A Mesoscale Measurement, Research, and Service Platform

Abstract

The Finnish Meteorological Institute and Vaisala have established a mesoscale weather observational network in southern Finland. The Helsinki Testbed is an open research and quasi-operational program designed to provide new information on observing systems and strategies, mesoscale weather phenomena, urban and regional modeling, and end-user applications in a high-latitude (~60°N) coastal environment. The Helsinki Testbed and related programs feature several components: observing system design and implementation, small-scale data assimilation, nowcasting and short-range numerical weather prediction, public service, and commercial development of applications. Specifically, the observing instrumentation focuses on meteorological observations of meso-gamma-scale phenomena that are often too small to be detected adequately by traditional observing networks. In particular, more than 40 telecommunication masts (40 that are 120 m high and one that is 300 m high) are instrumented at multiple heights. Other instrumentation includes one operational radio sounding (and occasional supplemental ones), ceilometers, aerosol-particle and trace-gas instrumentation on an urban flux-measurement tower, a wind profiler, and four Doppler weather radars, three of which have dual-polarimetric capability. The Helsinki Testbed supports the development and testing of new observational instruments, systems, and methods during coordinated field experiments, such as the NASA Global Precipitation Measurement (GPM). Currently, the Helsinki Testbed Web site typically receives more than 450,000 weekly visits, and more than 600 users have registered to use historical data records. This article discusses the three different phases of development and associated activities of the Helsinki Testbed from network development and observational campaigns, development of the local analysis and prediction system, and testing of applications for commercial services. Finally, the Helsinki Testbed is evaluated based on previously published criteria, indicating both successes and shortcomings of this approach.

Revised eddy covariance flux calculation methodologies – effect on urban energy balance

“…Black lines indicate the borders of the three sectors (urban 320Á408, road 40Á1808 and vegetation 180Á3208). area (Vesala et al, 2008). Furthermore, the station has formed a part of the Helsinki Testbed project since its beginning (Koskinen et al, 2011). For further information on the station and the measurement site, see Vesala et al (2008) and Ja¨rvi et al (2009a,b).…”

Evaluation of NWP results for wintertime nocturnal boundary‐layer temperatures over Europe and Finland

“…Helsinki Testbed consists of synoptic and road weather stations, masts and sounding stations (Koskinen et al, 2011). In the region (Figure 2), the surface elevation gradually increases to the northnorthwest with a gradient of approximately 2 m per 1000 m. The surface near the southern coast of Finland consists of mixed deciduous and coniferous forest, lakes, agricultural fields, small rocky islands, as well as Helsinki and smaller towns and villages.…”

Airborne laser scan data: a valuable tool with which to infer weather radar partial beam blockage in urban environments

“…The Finnish ALS data are organized in 3 km by 3 km tiles with an average point density of about 0.5 points m −2 . According to Ahokas and Kaartinen (2013), the ALS accuracy obtained in all various sur- (Koskinen et al, 2011). Recently, the Helsinki UrBAN (Urban Boundary-layer Atmosphere Network, http://urban.fmi.fi) project has started a long-term intensive observational network to study physical processes in the atmosphere above the city (Wood et al, 2013).…”