Niels Eduard Busch (born in 1936) is an eminent Danish meteorologist and research director, who played a key role in establishing a world-class research laboratory in micrometeorology near Roskilde in Denmark, within an institution formerly known as Risø National Laboratory, now DTU Wind Energy.
If you work in Wind Energy and already know Risø (the name of the small peninsula – “ø” means “island” in Danish – where the lab is located, by Roskilde fjord), you would for sure know about their meteorology department, and projects such as the Danish- and European Wind Atlases, or the WAsP software suite. These projects were carried out in the early 1980s, where Risø provided much support to the newly formed (modern) wind energy industry through, for instance, its turbine design- and certification services.
The story has been told already, see for instance the works of Matthias Heymann (AU) and Peter Karnøe (AAU), or this book by DTU released in 2019; yet, it usually starts in 1978 (with the creation of the Test Center for Small Wind Turbines), and the work carried out at Risø prior to that is only briefly alluded to (see p. 17 of ibid.) and generally not clearly laid out. As discussed elsewhere on this blog, while the discipline of wind turbine design is often being favoured by historians and generalogists, it forms only part of the field Wind Energy Engineering/Science. As the field draws from multiple other fields (Aeronautics, Meteorology, Structural Design, etc), I believe it is important to highlight not only breakthrough and discontinuities (moving from civil nuclear energy to wind energy for instance), but also continuities and long-lasting developments.
In this post, I will try to provide a more exhaustive- and continuous picture of the basic- and applied research work carried out at Risø from 1956 to the late 1980s; first by telling about the foundation of the Nuclear Energy Test Station at Risø, the works of Niels Busch here in Denmark but also at Pennsylvania State University (Penn State), and the continuation of micrometeorology research at Risø after that (Wind Energy being one, but not the only, field of application).
For writing this post, I have relied upon a number of documents, in particular:
- the lecture “Kansas 1968: Et nøgleeksperiment for udviklingen af mikrometeorologi“, given by Niels Busch at the Danish Meteorological Society meeting in Autumn 2015 (LINK, see also below).
- the Danish Technical Library research database, DTU Orbit (LINK)
The 1950s, the rise of microscale meteorology, and the case of Denmark
As explained by Niels Busch in his 2015 lecture (see link above), microscale meteorology took off in the 1950s, mainly driven by the rapid evolution of the aerospace industry, civil engineering and pollutant dispersion studies. The history of modern meteorology starts way earlier (mid 19th century), see this nice article, but it is fair to say that modern laboratories specialised in micro- and mesoscale meteorology only emerged after WWII, like the meteorology group at the Brookhaven National Lab on Long Island (equipped since 1948 with a 420-ft met tower).
Beside boundary-layer meteorology, other wind-related fields of science/engineering were very active in the 1950s. If you belong to the Wind Engineering community (wind loads on structures, etc), you surely know about Martin Jensen, who was a pionneer and well respected engineer (see this piece by Davenport). Wind Energy folks would surely recall Johannes Juul, student of Poul LaCour, who engineered the modern (three-bladed, upwind) turbine.
In Denmark, following the creation of the the Danish Atomic Energy Commission in 1955, a test center equipped with two nuclear reactors was built on the Risø peninsula in 1956-1957. The test center included, like at Brookhaven, a meteorology group equipped with a tall met tower (120 m, 394 ft, still standing) and all the necessary measurement equipment. Risø was also equipped with Denmark’s second computer, GIER (for Geodætisk Institut Elektronisk Regnemaskine). Shortly after, and following the example from Brookhaven and Risø, a 123 m tall tower was built in 1963-1964 at the Jülich Research Center in Germany. And the list goes on (see this article): in 1958 already, a 310 m tall tower was erected in Obninsk Russia; in The Netherlands, the 60 m Vlaardingen tower preceeded the Cabauw tower (213 m, 1972); etc.
The first report about the measurements “Preliminary Report on the Meteorological Measurements at Risø” was authored by Hans Bjerrum Møller (1932-2016) and Kaj Jensen, it was published in 1959. Kaj Jensen was in audience, during Niels Busch’s lecture in 2015; Niels thanked him, as well as Gunnar Jensen, Jørgen Christensen and Morten Frederiksen for all the good work with the measurement equipment. A later report, “Meteorological Measurements at Risø 1958 – 1961” was authored by Kaj in 1962. I have purchased a copy of the 1959 report, and shall make it available on Aeolians.net library shortly. In 1986, Gunnar wrote a report called “Med støvler, hjelm og sikkerhedsline – Meteorologi på feltfod” (which I am trying to locate), it translates roughly as “With boots, helmets and lifelines, Meteorology on the (battle) field”.
Niels Busch, from Risø to Penn State (1965-1967)
Niels Busch was born in 1936, and graduated in engineering. According to this source, he served in the Royal Danish Navy prior to joining Risø. The earliest reports authored by Niels Busch, “A micrometeorological data-handling system and some preliminary results“, and “A note on the similarity hypothesis for wind profiles” are from 1965, see abstracts in the Figure below. As explained in his 2015 lecture, one of the main research question at that time was about comparing predictions from the Monin-Obukhov Similarity Theory- and other assumptions about the ABL against field measurements (incl. Kolmogorov’s -5/3 law). This was being hampered by the difficulty of measuring 3D turbulence (which – still today – require some extensive amount of data analysis); there was no FFT yet, and spectra were derived by computing matrices of covariances, themselves computed using time series recorded on punch tapes (punch cards were used only from 1971) and processed using Denmark’s second computer model: GIER (it was unit no.3), manufacturered by Regnecentralen.
The results presented in these report were among the first in the word, and brought Niels Busch to Penn State in 1965 as visiting scholar. As he recalls during his 2015 lectures, those were the times, in the meteorology deparment, of Panofsky, Blackadar, Dutton; while across the street, in the fluid mechanics department, worked people like Lumley and Tennekes. If you don’t already know these giants, see the interesting, following links:
- about Lumley: “John Leask Lumley: Whither Turbulence?” (2018)
- about Blackadar: “The life of Alfred K. Blackadar. WxYz January 28, 2015“
- about Panofsky: “Panofsky, Hans Arnold“
Any wind energy professional has browsed at least once through an article which refers to the work on these people from Penn State. Niels Busch authored several papers and participated in research activities while in the US:
- “A summary of recent turbulence measurements at Brookhaven National Laboratory” (w/ Frizzola and Singer from Broohaven National Lab, 1967)
- “The micrometeorology of the turbulent flow field in the atmospheric surface boundary layer” (w/ Frizzola and Singer, BNL report, 1967)
- “A note on the Monin-Obuchov similarity hypothesis for fully turbulent flow with negligible horizontal mean-pressure gradient and a steady, parallel mean flow: Technical memo” (again w/ Frizzola and Singer, BNL report, 1967)
- “Recent spectra of atmospheric turbulence” (w/ Panofsky, 1968)
The Haven Acres / Windy Acres experiment (Kansas, 1968)
Niels Busch was in contact wih Duane Haugen, who had been heading, since 1961, the Boundary Layer Branch at the Air Force Cambridge Research Laboratories (AFCRL). At the time, and since 1965, the group was working (among other things) on a surface layer experiment called “Haven Acres” and then “Windy Acres“. As explained by Niels in the 2015 lecture, the goal was to measure turbulent fluxes and spectra in the surface layer, at a site where the assumptions of the similarity theory would be met; i.e. flat, and with stationnary flow conditions. For that purpose, the AFCRL was renting 5 acres of land between the towns of Liberal and Sublette in Kansas. A first experiment was carried out in 1965, and a second one in 1968, who became known as the “Kansas experiment” from which numerous papers and studies emerged. The most famous ouput of the project are the so-called “Kaimal spectral forms”, that are parametrised spectral form of the turbulent fluxes for various stability conditions. These have been used for wind turbine design, and are still widely used today (they are one of the two types of spectral forms in the IEC61400-1 standards).
Niels Busch, together with the Risø meteorology group (and Søren Ejling Larsen in particular) contributed to the project by installing a set of hot-wire anemometers which were used for verifying that the spectra obtained using the sonic anemometers were correct. You can read about this work in papers by Larsen (1972), Busch and Larsen (1976) and Larsen (1986). Back “home” at Risø, Søren and Niels did not use GIER, but instead some analog calculator (they mention this in the 2015 lecture).
A decade of ABL research (1967-1977)
As mentioned earlier, Niels Busch had tied close links with the Penn State micrometeorology community, and in particular with Hans Panofsky. When Panofsky died in 1988, Blackadar wrote an orbituary in the Bulletin American Meteorological Society, “Hans A. Panofsky 1917-1988“. In the same issue, there was a second orbituary entitled “Hans A. Panofsky and Meteorology at Risø, or HAP and Penn State East“, authored by the following members of the meteorology group at Risø: N. E. Busch, S.-E. Gryning, J. Højstrup, N. O. Jensen, L. Kristensen, S. E. Larsen, E. L. Petersen. The text is very touching, and mentions that:
In the 1970s, there was particularly intense traffic between Penn State and Risø. Most of us here at Risø have spent time at Penn State listening to HAP’s lectures and taking advantage of his intuitive physical insight. A large number of the Penn State faculty spent time at Risø, and HAP himself would usually come once a year. This is the reason why HAP called us “Penn State East”, which we considered an honor.
When back at Risø from 1967, Niels Busch and his colleagues set up a wide research program covering the principal aspects of ABL meteorology, including measurement technologies. This included clarifying (lobbying?), with the Danish authorities, about the roles and mandates of the existing institutions dealing with meteorology: as stated in “De danske vejrtjenesters struktur (1976)“, the Risø team becomes a specific- and independent meteorology group, focused on microscale meteorology, air pollution and measurement techniques; thereby it is make clearly different from what is today the Danish Meteorological Institute. Niels had a clear vision about his group’s objectives, as well as strong leadership in the global community of microscale meteorologists, see for instance his comments to the “Proceedings of the Symposium on Air Pollution, Turbulence, and Diffusion, December 7-10, 1971” (from page 275).
The various projects are listed in the Physics Department’s Annual progress reports during the 1970s, see the Table below.
| Year | Projects | Newcomer | Visiting/external |
| 1971 | Experimental equipment Climatology 1968 Kansas experiment Air-Sea interaction Analysis of Stochastic Data Series Applied meteorology (various) | L. Kristensen | H.A. Panofsky J.A. Dutton M. Jensen |
| 1972 | Velocity profiles Mesoscale effects in tower data Spectral analysis of climatological data Analysis of the Greenland Ice Data Climatology in Greeland Air-Sea interaction Applied meteorology (various) | P.A. Taylor W. Klug J. Taagholt | |
| 1973 | Wind profiles at Risø Turbulence in the atmospheric surface boundary layer Numerical Modelling of the Wind Structure in the PBL Air-Sea interaction I (Kattegat) Air-Sea interaction II (JONSWAP) Fine Structure Experiment Climatology in Greenland Spectral Analysis of Climatological Data Statistical Analysis of Extreme Wind Velocities Applied meteorology (various) | N.O. Jensen O. Christensen N.W. Nielsen | E.W. Peterson C.H. Gibson N. Boston J. Taagholt |
| 1974 | Change of Terrain Roughness Atmospheric Gravity Waves Simulation of Atmospheric Turbulence Time Series Analysis Digital Noise Air-Sea Interaction Fine Structure Experiment Climatology in Greenland Numerical Modelling of the Planetary Boundary Layer Stress-Profile Experiment Wind Power Dynamic Wind Loading Applied meteorology (various) | K. Hedegaard | E.W. Peterson R.H. Jones R.A. Anthes S. Chang J. A. Dutton |
| 1975 | Flow over Non-Uniform Terrain Stress-Profile Experiment Simulation of Atmospheric Turbulence Numerical Modelling of the Planetary Boundary Layer Air-Sea Interaction (JONSWAP – 1975) Air-Sea Interaction (Kattegat-1975) Climatology of Wind Direction Fluctuations Climatology in Greenland Time Series Analysis Development of an Automatic Weather Station (AWS) Over-speeding in Cup Anemometers Acoustic Sounder Cold Wire Technique Dynamic Wind Loading Applied Meteorology I: Site Evaluation Applied Meteorology II: Air Pollution Studies | S. E. Gryning E. Lyck | E. W. Peterson J. A. Dutton R.A. Anthes S. Chang H.A. Panofsky J. Taagholt P. Dorph-Petersen K. Rasmussen |
| 1976 | Numerical modelling of the planetary boundary layer Wind-direction measurements at the Risø tower Climatology of the Horsens fjord area Cold wire technique Dynamic windloading Nuclear meteorology Determination of atmospheric dispersion in the urban environment by means of tracers Diffusion over land and over water in near-calm, very-stable conditions | C.J. Christensen | R.A. Anthes S. Chang K. Rasmussen M. Nansen Nielsen |
| 1977 | Flow over non-uniform terrain Numerical modelling of the planetary boundary layer Air-sea interaction Quantitative sodar measurements of atmospheric turbulence A phase-locked loop, continuous wave, sonic anemometer- thermometer Measurements of high-frequency temperature fluctuations Dynamic wind loading | J. Højstrup I. Troen D.W. Thomson S. Frandsen | E. W. Peterson K. Katsaros R.A. Anthes S. Chang R.M. Williams F. Weller J.A. Businger C. Gibson |
As the years go, familiar names appear (to the wind energy professional): Niels Otto Jensen, Sten Frandsen, Leif Kristensen, Jørgen Højstrup, Svend-Erik Gryning. Yet, an until 1977 where the first measurements from the refurbished Gedser turbine were available, not much of the work carried out in the meteorology department had to do with wind energy. Instead, either basic research studies were carried out, or applied meteorology was destinated to pollution dispersion. Yet, from all the works mentioned above, many of them should become very relevant to wind energy projects; in particular the work on turbulence in the surface layer, wind speed profile changes to do consequent, multiple roughness changes, and cup anemometry.
Wind Energy, increasingly (1978-1987)
As mentioned earlier the test station for small wind turbines was created, at Risø, in 1978 (following a decision by the government in 1976, if I recall well). But how did that happen? See what the Wind Turbine Industry magazine from June 2001 tells us (page 12): Helge Petersen from Risø, who was taking part to the Tvind turbine project, was also part of the council for wind energy; as they were looking for a place for creating a test center (like those in the US), it is actually Niels Busch (vice-director at the time) who helped make this happen (most of Risø was against hosting the test center).
From here-on, start the more well known story of Risø and Wind Energy. First came the Danish Wind Atlas, then the NIBE turbines, FLEX (Stig Øye), the European Wind Atlas, WAsP, and cluster wake studies. The number of publications increases drastically, and so does the number of employees and researchers in the meteorology department.
During those years, the connection between the fluid mechanics department at the Technical University of Denmark (in Lyngby, North of Copenhagen) was made. There, people like Maribo Petersen (involved in the IEA-IEC certifcation works), Martin O.L Hansen (aeroelasticity), Kurt Hansen, and later Jens Nørkær Sørensen have been working with turbine aerodynamics and measurement technologies. This small (but dense) department is often forgotten, and I hope that they will be mentoned in future Risø retrospectives.
Between 1981 and 1987, Niels Busch was Risø’s director. In 2002, in an article called “Hindsight and Foresight“, he writes:
Does boundary-layer meteorology have a future? We believe so. It appears obvious that mesoscale modelling is the crank, but is equally obvious that mesoscale modelling quickly is getting close to the point, where it is not computer power that limits the usefulness of the model results but rather the understanding of the subgrid processes, processes that may or may not be describable in terms of ordinary algorithms.
This has at least two consequences. The one is that we should be looking for alternatives to straightforward number crunching of differential equations. The other is that we need an increasingly intelligent interface between the basically rather simply-thinking mesoscale model and the complications that the real world presents in terms of chemical and biological processes, which by nature, or because of small space and time scales, cannot be resolved in mesoscale models.
We also make the observations:
1. That money tends to come from where big money is (e.g. wind power projects and infrastructural projects with relatively shortsighted research strategies),
2. That care should be taken to preserve a strong element of strategic research in boundary-layer meteorology,
3. That models are necessary, but that strong ties to physical validation are an imperative,
4. That non-elephants are difficult to attack scientifically, and
5. That there is no substitute for the real world, so numerical experiments may guide but cannot take the place of physical experiments and observations.
Niels Busch was, by all means, a strong advocate for doing basic research (and calling it basic resarch), as much as for doing applied research (and calling it applied research). What ties both together is a long-term vision, not entirely separated from politics, but not entangled neither.
I hope that I have convinced my dear readers about the necessity to know- and aknowledge Niels Eduard Busch’ work at Risø. He became CEO of the Storebælt bridge (a project to which Risø provided much consultancy work) in 1988, and later on took the head of the Teknologisk Institut. May he and his colleagues be thanked for their contributions.
Comments/suggestions are welcome.
Rémi
This article was updated on 2020-08-21, following discussions with Niels Buch and Sven-Erik Gryning; thank you both!
