Welcome to the meteoLCD blog

September 28, 2008

This blog started 28th September 2008 as a quick communication tool for exchanging information, comments, thoughts, admonitions, compliments etc… related to http://meteo.lcd.lu , the Global Warming Sceptic pages and environmental policy subjects.

16th September Ozone Layer Preservation Day

September 18, 2014


The 16th September is the International Day for the Preservation of the Ozone Layer!

This 16th September is meant to commemorate the 1987 Montreal protocol banning human made ozone depleting gases, like chlorofluorocarbons. Read here a longer explanation of the chemical reactions which reflects the traditional view.
This NASA graph shows that a few years after Montreal, the yearly minimum of ozone layer thickness at the South Pole stabilized (but did not markedly recover!). The scientific reasons for the ban, which seemed complete and rock-solid at that time, are becoming gradually more uncertain, as more natural sources of ozone destroying gases were found (e.g. bromides emitted by plankton) and a new mecanism in the South Seas has been detected. Also unexpectedly new gases have been found recently that seem to destroy ozone.
Caring for the ozone layer is noble, but as often in environmental problems much hype and hysteria muddled the problem; above all, the science really is not settled!
MeteoLCD measures the thickness of the ozone layer above Luxembourg since 1998, and the linear trend does not show an ongoing thinning; neither are the UVB irradation levels increasing (look at the trends page). Look also here for the results of the Uccle station, which is one of the longest acting measuring stations in the world.

1. data show no continuing further thinning of the ozone layer.
2. the natural occuring ozone hole above Antarctica has stabilized.
3. in our regions, the trend is more on an increase of the layer. The UVB irradiation at ground level is not increasing.
4. In our region the thickness of the ozone layer often varies tremendously on extremely short periods. To expect a constant thickness of the ozone layer is foolish.

PS1: you may read Matt Ridley’s comment in The Times :The Ozone Hole Isn’t Fixed. But That’s No Worry (go to chapter 6 here)

PS2: here is the report of the EEA on the European emissions of ozone depleting substances

The 6th July 2014 storm… and radioactivity peak.

July 7, 2014

See new additions at the end of the text!

Some parts of Luxembourg were under a severe storm during the late afternoon of the 6th July 2014. Wind gusts were very high (we measured a half-hour maximum of 15 m/s (54 km/h, i.e. a maximum of the average over 30 minutes) which is considerable for a location at the bottom of a valley. Our backup Vantage Pro station measured a high wind maximum of 25 m/s (90 km/h, this is an instantaneous maximum, not an average over some time interval), so no wonder that quite a lot of trees went down or lost branches. The atmospheric pressure dip (average over 30 minutes) was not spectacular: about -4 hPa (mbar),  but this seems sufficient to cause very strong winds. Our lightning sensor was down, which is a pity, for we missed to  record a nice storm activity. Precipitation (rainfall) peaked at about 20 mm in half an hour, and the corresponding atmospheric radioactivity surge due to radon washout was  27 nSv/h.


So lets go back to our previous discussions of radon washout (here and here) and update the graph relating radioactivity peak to precipitation pulse.


A linear fit forced through the origin is impossible: R2 = 0 ! The affine fit Rad_peak = a + b* Rain_pulse gives a slope of 0.45, i.e. every mm of precipitation pulse would increase ambient radioactivity dose-intensity through radon washout by 0.45 nSv/h. This very low value (to be compared to 7 given in the previous discussion) points to sort of a saturation effect. Let use imagine that a rain pulse of infinite intensity (hm!) would washout all radioactive radon daughters contained in a surrounding volume (a column of a certain height and a certain diameter for instance). Then a better model would be a logarithmic one,  something like radon-peak = a*log(b*rain-pulse) +c, where log is the natural logarithm ( a still better model would have a horizontal asymptote). This gives indeed a better picture with a GOF of R2 = 0.29.:


In this discussion, only measurements were there is an interval of at least 3 days between the rain-pulse have been retained. The 8 Sep 2013 data point seems rather odd: may be it is the outlier spoiling a nice model!

Let’s close with a very simple model using a rational function, which has a horizontal asymptote but will not be forced through the origin:

radon_washout_06Jul14_rationalmodelHurrah: the goodness of the fit now jumps to R2 = 0.33. If the rain_pulse x tends to infinity, the rad_peak will reach the asymptotic value of 30.26 nSv/h. When the rain_pulse is zero, we should expect a radon-peak being also zero: we are close with 1.1 nSv/h.

Time to leave the playground, but this amusing topic will be continued…


Additional comments (08 July 2014):

Patrick Breuskin from the Division de la  Radioprotection and  a meteoLCD collaborator from time to time sent me his measurements made at 3 different locations by an AGS421 gamma counter (sampling interval = 10 minutes): AGS421_7235 is installed on the deck of meteoLCD, AGS421_7288 at the Findel airport and AGS421_7199 is measuring at Esch-Alzette. I annotated his graphs, which are shown here in the same order:

20140706AGS7235StormRain_annotated 20140706AGS7288StormRain_annotated20140706AGS0199StormRai_annotated

Obviously all instruments show a radiation peak coincident with the precipitation pulse. Expressed as percentages above the previous background levels, the radiation peaks are:

Diekirch meteoLCD:  33 %               (baclground 83 nSv/h)

Diekirch AGS421     :  47% (54%)    (background 83 nSv/h)

Findel airport:             83%               (background  113 nSv/h)

Esch-Alzette:               37%                (baclground  132 nSv/h)

The two Diekirch and Esch-Alzette peaks are relatively close. As the meteoLCD reading is an average over 30 minutes, one should expect lower values than the 10-minutes sampled AGS421_7235 located on the same deck. The high value of 83% at Findel airport is a bit of a surprise: as this airport is located at about 360m asl, and much more exposed to wind than the other stations. Could it be that higher wind-speeds push the radiation peaks up?

Here are the wind speed peaks rounded to the nearest integer:

Diekirch meteoLCD:  15 m/s

Findel airport:             13 m/s

Esch-Alzette:     not available

These wind velocities are comparable, so wind speed does not seem to influence the relative radiation peak; neither does the background level which is highest at Esch-Alzette without yielding a higher relative radiation peak. Possibly the level of the precipitation pulse is the main factor contributing to the intensity of the radon washout. The Findel measurements are not yet available, and the closest station from ASTA is that of Merl which shows only 14.2 mm.

Well you know the tune “We need more data!”, so lets be patient.


Radon washout (2)

April 26, 2014

In August 2013 I wrote a small comment  on ambient air radioactivity peaks coincident with a sharp rain fall pulse. Several specialists like A. Kies and M. Severijnen confirmed that these observations show a wash out of the radioactive daughters of the ubiquitous radon gas. This year a similar event happened the 21th April 2014:


Note that the 2 mm rain fall pulse triggered a radiation rise of about 20 nSv/h above the base level. One also sees that the much lower rain fall pulse (0.8 mm) which happened the next day does only a minor radiation peak.

Several interesting questions can be asked:

1. Is there a minimum time between two rain fall pulses needed to cause strong radiation peaks?

Or in other words: how long does it take for the atmosphere aerosol content to recover after a first washout?

The observations made in August 2013 suggest that 1 day could be enough:


The first rain pulse (1.2 mm) causes a radiation peak of about 14 nSv/h; the second much stronger rain pulse (2.2 mm) triggers a radiation peak of comparable amplitude: this could be a hint that the atmospheric aerosol load has not quite recovered to the previous level (which would be the base line after 3 dry days).

A week in September 2013 gives a similar picture:


Here we see two strong similar rain pulses of about 4 mm separated by about 48 hours: the first triggers a radiation peak of about 35 nSv/h. and the second of only 15 nSv/h. A close inspection shows that this second rain pulse actually is double, a first of 2.8 mm followed a couple of hours by a second of 4 mm. The radiation curve peak also shows these two peaks, with again the second (corresponding to a higher rain fall) less than the first.
The conclusion is that a simple relation-ship of the form radiation-peak = f(rain pulse) can not be established without respecting this atmospheric recovery time lapse.

2. Is the radiation peak proportional to the rain fall pulse?

Using only our miniscule set of observations from 2013 and 2014, let us just keep the (rain pulse, radiation peak) points separated by a minimum of 3 dry days:


The plot shows that the slope of the regression line is 7.09. i.e. the first rain-fall pulse of 1 mm causes on average a radiation peak of 7 nSv/h. The goodness of the fit is rather poor (R2 = 0.28), and this analysis shouts for more data!



An analysis of the relationship between rain pulse and radiation peak intensities must respect the time lapse needed for the recovery of atmospheric aerosol load, possibly 3 dry consecutive days . This first short study suggests a possible linear relationship with a slope of 7 (nSV/h)/mm .

RAF revisited (total ozone column and UVI)

March 8, 2014

In April 2013 I used a period where total ozone column (TOC) made a spectacular plunge to calculate the RAF (Radiation Amplification Factor) which tells us by how much the UVI (or biologically effective UVB) will increase when the total ozone column becomes smaller.  This month (March 2014) we had a relatively low TOC of 276.5 DU the 7th March, followed the next day by a DU of 328.1. Sky conditions, total solar irradiance and solar angle were practically the same, so that TOC is the only factor influencing UVI. The calculation gives an RAF = 1.17, similar to the value found last year. Broadly speaking, if TOC diminishes by 20%, UVI increases by 20% (here -18.7% for DU and +18.2% for UVI).

See also this paper from last year.


The values used to compute the RAF are the UVI’s, which are proportional to the mMED/h given as red curve in the graph (1000 mMED/h = 25/9 UVI, see here).

2013 in review

December 31, 2013

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

A New York City subway train holds 1,200 people. This blog was viewed about 4,200 times in 2013. If it were a NYC subway train, it would take about 4 trips to carry that many people.

Click here to see the complete report.

The winters they are cooling!

November 25, 2013

The EU wants to spend 20% of its budget to avoid “dangerous global warming” (now called “climate change”), but it seems unaware that winters in the EU zone are steadily cooling since quite a long time. I pointed to our meteoLCD data showing this trend for a couple of years, and our latest trend graph for the period 1992 to 2012 showed this:


The overall trend for Diekirch is -0.42 °C/decade (that of our national meteo station at Findel airport even -0.67 °/dec).  Ed Caryl has a comment at the Notrickszone blog of Pierre Gosselin, where he examines winter trends from the GISS data. The global figure shows this:


Luxembourg belongs to the light-blue region, which means that the trend for the 1995-2012 period of 18 years is between -0.5 and -1.0 °C, which gives a decadal trend of -0.28 to -0.56 °C/dec (with a mean value of -0.42 °C/decade, really close to the meteoLCD trend).
The analysis of the Diekirch data shows that the winter temperatures correlate very well with the NAO index of the December to March months. The coming years will tell us if this not so surprising correlation remains stable.

I wonder that absolutely NONE of our climate anxious politicians and NGO’s seems to recognize this situation, which is an observable fact and not a prediction of some climate models ensemble. Colder winter will be problematic, as they stress the energy needs for heating, and collide with the ambition to continuously lower energy usage.

The Austrian meteorologist Dominik Jung found the same winter cooling throughout the Alps, which should comfort the managers of the various sky resorts who have been continuously told by the climate alarmists that sky resorts have no future due to climate warming.

German subsidies: EEG 17 billion, research/education 13.7 billion !

October 26, 2013

The 44/3 edition of  europhysicsnews, the journal of the European Physical Society, contains an interesting comment by its former president Fritz Wagner titled “The pitfalls of time derivatives”. You may read it here (highlights by me).

The author writes that last year (2012) the total subsidies for the Energiewende were 17 billion Euros (17*10**9, billion always used in the US tradition), to be compared to the 13.7 billion of the federal science and education budget!

The Bundesministerium f. Umwelt, Naturschutz und Reaktorsicherheit gives more recent and higher numbers in his latest brochure: the total EEG costs are about 20.4 billion Euros in 2013 and will rise to 23.6 billion in 2014 !

Being a fusion researcher, F. Wagner belongs to a category of German scientists I wish good courage to stem the tide of the hysterical “anti-atomism” embraced by the large majority of the German  media and politicians. The last sentence of his opinion-paper reminds us that the electricity production of Norway, Sweden and France is essentially CO2 free, a fact not welcome in his country!

Read also on this subject an interview (in German) with Dr. Günther Keil, president of the “Deutscher Arbeitsgeberverband”: “Nur Dilettanten beschließen Maßnahmen, deren logische negative Auswirkungen sie nicht sehen können.”

Decline in wind power: the slump in capacity factors.

September 20, 2013

In the preceeding comment I showed using the IWES report that the decadal decline in potential wind power was about 14% per decade during the 1992-2012 time period in Germany (coastal and land locations). Such an important decline of the available wind resource should be show up in the electricity produced by the wind turbines. The easiest metric to use is the capacity factor (CF) or the equivalent parameter “Volllaststunden”. (VLh) prefered in German reports. The relation between both parameters is  CF = VLh/8760.

1. The ThinkAero data

It is not easy to find reliable data,so I will start with the data found at the ThinkAero blog. Here we have a table which gives the average VLh of all German wind turbines and also those located in the Land Baden-Würtemberg.

Volllaststunden_BRD_2004_2011The upper red data points represent the German average, the lower blue squares the numbers for in-land Baden-Würtemberg. Trend lines have been computed with Excel. Clearly both groups show declining VLh’s (or CF’s).

As in the previous comment, we clearly find that the year 2007 was an exceptional good one, both for the whole country as well as for Baden-Würtemberg.

For the whole country, the decline given by the trend line would be 62.5 hours per decade, or about -4%/decade (percentages calculated w.r. to the trend line).  The same calculation made for Baden-Würtemberg gives -181 hours per decade or -14.8%/decade.

The situation in Baden-Würtemberg becomes dramatic during the last 4 years 2008 to 2011:


Here we see a decline of -32% during that short period. Needless to say that such a slump will make all economic predictions a laughing-stock!

2. The BMU data

The website of the BMU (Bundesministerium f. Umwelt…) has a data table with values from 2000 to 2012. To be able to compare to the ThinkAero data let us just use the results from 2004 to 2012:

Volllaststunden_BMU_2004_2012The trend line gives a decadal decline of -4.6%.

If we use the ThinkAero data and add the BMU value of 1530 for the year 2012, the same calculation gives a decadal decline of -3.5%, close to the BMU result.

3. The BWE data

The Bundesverband WindEnergie gives a table with the “Windjahr” percents (actually these are anomalies of probably the wind resource (not the produced wind electricity) over an unspecified period, probably a decade):

Here again we find a decline of -12.2% per decade (computed from the trend line), a number close to those found in the preceding comment. And as is the case for Baden-Würtemberg, the last 4 years are especially worrying.

3. Conclusions

1. Both the wind resource data and the capacity factor (or Volllaststunden) data show a (long-term) decline

The 2 series we have studied give the following decadal declines in percent for the period 2004 to 2012:

ThinkAero (Volllaststunden): – 3.5%
BMU (Volllaststunden) :           – 4.5%
The declines in wind resource given by the IWES report (preceeding comment) and by the BWE are comparable (-14% and -12.2%)

2. Especially instructive is the comment given in “Energiewirtschaftliche Tagesfragen” from September 2013: “Bisher ist ein Trend zu steigenden VLS trotz stetiger technischer Weiterentwicklung durch Serienproduktion und rapide gestiegene Anlagenkapazitäten und Nabenhöhen nicht erkennbar.”

Approximate translation: “Up until now a rising trend in CF’s can not be detected, despite technical progress and fast rising power capacities and wind turbine heights”.

It would be more correct to acknowledge that an uncomfortable declining trend  is clearly detectable!

The dramatic decline in available wind power

September 19, 2013

In two previous comments (here and here) I wrote about declining wind power and declining capacity factors of installed wind turbines in Europe and especially in Germany and Ireland. The German Fraunhofer “Institut für Windenenergie und Energiesystemtechnik IWES” has published a very interesting report “Windenergie Report Deutschland 2012” which I recommend for reading to everyone interested in wind energy, be he a 100% fan or a more skeptic individual. Sure, the IWES must be on the side of the wind power pushers, but this report has serious scientific reflections and, if you read it carefully, they do not refrain to put the finger on spots that hurt (click here for an English version).


I intend to write a couple of comments on this report; this first one will exclusively document the dramatic decline in available wind power over Europe during the last 21 years.

1. The potential wind velocities over Europe.


This picture taking from a EEA report shows the mean wind speed over sea and land (I do not know if this a an average over a certain period neither at what height above ground it is measured, so let us take it simply as a rough indicator). Wind power in W/m2 is proportional to the cube of wind speed and to the air density (P = 1/2*density*speed**3), so to convert to W/m2 multiply the cube by 1.25 as the density of air is about 2.5). This gives approx. 1.25*1000 = 1250 W/m2 for offshore locations , and this number must be approximately divided by 3. The main unsurprising result is that offshore potential is much higher that onshore. Onshore potential at 5 m/s is only  5**3/10**3 = 0.5**3 = 1/8 of offshore potential.

2. The year 2012 with respect to the long time mean over 20 years


This picture from the report clearly shows that at most locations the 2012 wind potential is considerably lower than the 20 year mean: onshore locations in Germany are about 20% lower than this mean. The blue color describing lower potential is dominant if we neglect the offshore locations at great distances from shorelines.

3. The trend over 21 years for German locations.

The IWES report has another figure, that documents the real dramatic decline for various German wind power locations. I have digitized the curves relative to the coastal (“Küste”) and northern plain regions (“Norddeutsche Tiefebene”) using the wonderful UNSCAN-IT software, and calculated the linear trends:

Winddargebot_1992_2012_annotatedThis figure (modified fig.34 of the report) shows an eye-opening decline from 1992 to 2012, with the 2007 peak being a real exception. The trend lines have approximately the same slopes: at coastal and plain locations, potential wind power decreased by ~100 W/m2 (-29%), which gives a decrease of roughly -14% per decade (percentages calculated w.r. to the start point of the trend line) !
This is a very worrying trend for wind power, and one wonders why this trend is mostly ignored in the media and political discussions. The extreme increase in yearly added wind turbines masks this decline of the available resource. But if the installation of new turbines comes to a halt due to saturation, the negative trend (if it continues…) could well spell disaster for wind energy production and investors.

PS: The ZHAO et al. paper I referred to in a previous post finds a decline of  -2.9% for wind velocity per decade (from 1978 to 2008). This results in approx. -24%/3 = -8% per decade in wind power (the divisor 3 represents very roughly the usual efficiency of wind turbines).


IWES: Windenergie Report Deutschland 2012. (link)

MASSEN F., 2013:  Bad wind, lower wind power, exploding costs. (link)

MASSEN F,. 2011:  Wind Power (link)

MASSEN F., 2011:  Réflexions sur les éoliennes (link)

ZHAO et al: Is Global Strong Wind declining? Advances in Climate Change, 2011.

The O’Dowd paper on aerosols and global warming.

August 26, 2013


There is a lot of discussion in the blogosphere on the paper Cleaner air: Brightening the pollution perspective?” by  O’Dowd et al. (paywalled!) which suggests that European warming of the last decade(s) is (also) caused by a sky brightening: the good results of air-pollution control lead to a rise in the negative radiative forcing of the aerosols (i.e. the negative forcing becomes less negative), and as a consequence solar irradiance at ground level increases. This increase is at least partially responsible for the observed warming.

Colin O’Dowd and co-authors have published a similar free-access article in issue 11 of the bulletin of Royal Irish Academy’s Climate Change Sciences Committee (here). Wang et al published in 2012 a paper “Atmospheric impacts on climatic variability of surface incident solar radiation” which essentially follows the same path.

What makes me uncomfortable, is that both authors clearly affirm that we have an ongoing solar brightening in Europe (brightening and dimming is a seen as a decadal change in solar irradiance). Here is a figure from Wang’s paper showing the situation in Europe:

Wang_Climate_variabilityThe green line shows the anomaly (5 years smoothing applied) of solar irradiance, the blue of the inverted atmospheric optical depth (-AOT) and the red of the free (= cloudless) sky fraction. Clearly AOT declines after 2000, and solar irradiance increases.

O’Dowd et al conclude their investigation with “…the trends of reducing anthropogenic aerosol emissions and concentrations, at the interface between the North-East Atlantic and western-Europe, lead(ing) to a staggering increase in surface solar radiation of the order of ∼20% over the last decade.”

These are strong words, and paint a situation that is the contrary of what I have been measuring since about 15 years. Actually, in Diekirch (Luxembourg) we have an ongoing solar dimming since 1998, which has even become stronger after 2003 (the heat-wave year I would not dare to take as a starting point for a regression line!)


There also is no warming here, but we even measure a slightly cooling since 2002 (see here). What gives me some comfort that our measurements are not picked out of the blue, are the satellite data from Helioclim for Luxembourg (which alas stop at 2005):

Helioclim_solar_dimming_Luxbg_1985_2005The Helioclim plot shows a long-time dimming over two decades for Luxembourg!

Martin Wild from ETH (Zürich, Switzerland) is one of the world specialists in global dimming/brightening, and co-author of the Wang and Norris papers. He asserts that there was a dimming in Europe from 1950 to 1980, followed by two brightening periods of different magnitude from 1980 to 2000 and after 2000 (see here). So he is in consensus with the two other authors.

Assuming these authors correct, global European trends may clearly be very different from those of smaller specific regions. So one should be cautious to generalize a broad picture to regional scale, where the exact opposite might go on.

Let us conclude with another paper by Norris et al. “Trends in aerosol radiative effects over Europe inferred from observed cloud cover, solar ‘‘dimming,’’ and solar ‘‘brightening’’” which use the GEBA archive (Global Energy Balance Archive) and which give this picture:

GEBA_global_radiation_trendsGEBA_global_radiation_trends_legendThe blue dots correspond to decreasing, the red to increasing irradiance. Now watch the right part and the legends: all crossed circles correspond to statistically not significant trends, and clear circles to a situation where 25% or more data are missing. If we leave out these measurements, not much remains in the 1987-2002 part which allows to conclude to a brightening. Here the right part magnified:


If you keep only the statistically significant points and those with enough data you have 3 cooling points (Germany, France, Bulgaria) and three brightening (2 in northern Italy and one in Finland), see the arrows. Not so impressive!



  • Colin O’Dowd, Darius Ceburnis, Aditya Vaishya, S. Gerard Jennings, Eoin Moran : Cleaner air: Brightening the pollution perspective? AIP Conf. Proc. 1527, pp. 579-582; doi:http://dx.doi.org/10.1063/1.4803337 (4 pages)
  • K. C. Wang, R. E. Dickinson, M. Wild, S. Liang: Atmospheric impacts on climatic variability of surface incident solar radiation. Atmos. Chem. Phys., 12, 9581–9592, 2012. http://www.atmos-chem-phys.net/12/9581/2012/ doi:10.5194/acp-12-9581-2012 (link)
  • Joel R. Norris, Martin Wild:  Trends in aerosol radiative effects over Europe inferred from observed cloud cover, solar ‘‘dimming,’’ and solar ‘‘brightening’’. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D08214, doi:10.1029/2006JD007794, 2007 (link)


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