Total Ozone Thickness 2024

jump straight-on to the data

Look here: 1. Intercomparison between the ozone measurements of the Microtops II and those made by the Brewer instruments at the RMI at Uccle: 2017, 2016, 2012, 2011, previous years.
New: compare the 2023 TOC readings as published by Uccle on their website and meteoLCD measurements, look at these graphs (Excel file here)
3. 3D plot of total ozone column for latitude region [45 to 50] from 1964 to 2007 and  maps of all of meteoLCD measurements (from WOUDC, many years missing!)
4. Older dobson files are in the data archive

other near-live or very recent total ozone data:
Thickness of the ozone layer at Uccle Measured by the Royal Meteorological Institute (RMI) of Belgium; shows mean and variance of all data from 1971 on.
Click here for .xlsx file of same-day values of meteoLCD and Uccle's Website (irregular updates!)
Ozone Distribution (NH + SH) Global Ozone maps from NASA
Northern Hemisphere Ozone Map (not available) Ozone map generated from all Northern Hemisphere stations by the WOUDC

The coordinates of DIEKIRCH are:
latitude = 4952' North 
longitude = 610'
altitude = 218 m a.s.l.
click to enlarge!

Location Date UTC Time Thickness [DU] Sky Condition Ozone&NO2 [ug/m3] **
Diekirch 03Mar24 09:41 412.7 some clouds 69.9
Diekirch 02Mar24 11:24 417.3 many clouds 103.9
Diekirch 01Mar24 11:12 377.7 heavy clouds 89.3
Diekirch 29Feb24 14:06 333.0 blue sky 80.7
Diekirch 28Feb24 11:38 371.0 light haze 63.5
Diekirch 27Feb24 12:02 380.9 many clouds 59.0
Diekirch 02Feb24 12:12 321.5 light haze 76.5
Diekirch 01Feb24 11:56 362.9 many clouds 81.7
Diekirch 31Jan24 12:00 363.8 some clouds 77.9
Diekirch 29Jan24 12:01 327.9 hazy 45.5
Diekirch 28Jan24 12:05 334.0 blue sky 44.8
Diekirch 27Jan24 12:00 352.0 light haze 22.5
Diekirch 26Jan24 12:33 332.0 many clouds 80.0
Diekirch 24Jan24 11:32 335.7 heavy clouds 75.0
Diekirch 21Jan24 10:18 370.5 light haze 4.9
Diekirch 19Jan24 12:03 420.0 light haze 47.2
Diekirch 18Jan24 11:28 326.1 light haze 42.6
Diekirch 16Jan24 11:58 291.5 some clouds 40.4
Diekirch 15Jan24 11:54 357.1 heavy clouds 27.9
Diekirch 11Jan24 13:10 318.8 blue sky 29.4
Diekirch 10Jan24 11:30 336.8 blue sky 30.0
Diekirch 09Jan24 10:30 425.3 blue sky 38.5
Diekirch 04Jan24 11:27 321.3 many clouds 67.4
Diekirch 03Jan24 10:03 295.1 heavy clouds 73.9
Diekirch 01Jan24 10:49 291.3 heavy clouds 64.4

The total thickness of the (stratospheric) ozone layer is measured at unspecified, irregular intervals using the handheld Microtops II sensor manufactured by Solar Light Company of Philadelphia. This instrument measures the thickness of the ozone layer by computing the ratios of UVB irradiances measured at three different wavelengths; the water vapour content of the atmosphere and the AOT (aerosol optical thickness) are also measured by the instrument.
The measurement results are given in DU (Dobson Unit). 100 DU correspond to a total thickness of 1 mm, if the ozone layer were at a standard atmospheric pressure of 1013.25 [HPa]. Common values are in the 250..350 DU range.

The previous years dobsonyy.html files and the Microtops measurement files can be found in the data area!


1. Starting 01-Apr-2021 a new calibration factor of 0.9466 is applied to #3012 measurements by Mike Zimmer. This new factor is the result of a comparison made from 08 to 23 March 2021. #3012 readings multiplied by this factor are given in blue.

2. Green DU's correspond to a new calibration factor of 0.9422 applied to #3012 measurements by Mike Zimmer starting 02Jun16 ! This new calibration factor has been found by a new comparison over several measurements made from March to July 2016.

Starting 15 Sep 2009, Microtops #5375 is back from calibration at Mauna Loa. Purple data correspond to the new calibrated readings. There is a big difference between the readings before and after calibration. For some time, measurements will be made with both Microtops, and a conclusion drawn thereafter.

Green ground ozone data should be considered unreliable!

(**)  Ground ozone:
The O3&NO2 concentration is given for the actual temperature and pressure conditions. It is NOT corrected for STP conditions! As the NO2 concentrations is practically negligible (below the sensor threshold of 40 ug/m3, the readings should be taken as O3 concentration.

The "old" CAIRSENS O3&NO2 has been replaced by a new model the 15th May 2020. This new Cairsens seems to have a strong positive bias. As our O3 values are very close to those measured by the official station at Beckerich (confirmed by several comparisons), a calibration function will be applied in the datalogger starting 1st July. Correct_O3 = 1.074*reading - 36.309. This function as been applied to all the ground ozone values from 16 May to 29 June (numbers in red) which have not been corrected by the logger. Please read the NEWS from 1 July 20 for the various graphs.
Update 01-Apr-2021: The calibration factor used in the logger has been changed to 1/0.6656 and the offset to -27.8 (see the NEWS from 31-Mar-2021). This will apply to all readings from 01-Apr-2021 on.

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