Total Ozone Thickness

Location	Date	UTC Time	Thickness [DU]	Sky Condition	Ozone&NO2 [ug/m³] **
Diekirch	28Apr24	08:08	421.2	many clouds	104.9
Diekirch	27Apr24	12:52	407.8	many clouds	100.0
Diekirch	26Apr24	11:03	428.0	many clouds	96.7
Diekirch	24Apr24	10:54	427.0	some clouds	86.7
Diekirch	22Apr24	10:28	435.2	heavy clouds	94.3
Diekirch	21Apr24	13:53	420.6	many clouds	85.3
Diekirch	18Apr24	10:22	436.1	heavy clouds	84.6
Diekirch	16Apr24	10:47	461.2	heavy clouds	92.0
Diekirch	16Apr24	11:50	449.1	many clouds	97.8
Diekirch	15Apr24	11:10	370.2	some clouds	110.8
Diekirch	13Apr24	12:07	275.2	some clozds	97.9
Diekirch	11Apr24	11:35	338.9	many clouds	97.2
Diekirch	10Apr24	12:30	360.5	some clouds	94.0
Diekirch	08Apr24	11:30	341.4	many clouds	92.1
Diekirch	28Mar24	11:10	468.6	some clouds	96.5
Diekirch	26Mar24	11:58	379.1	heavy clouds	89.8
Diekirch	25Mar24	12:17	340.4	some clouds	92.9
Diekirch	24Mar24	12:04	413.2	many clouds	90.9
Diekirch	23Mar24	12:02	369.7	heavy clouds	98.6
Diekirch	22Mar24	12:41	325.1	some clouds	92.3
Diekirch	21Mar24	12:09	350.3	light haze	101.8
Diekirch	20Mar24	11:37	336.6	light haze	89.1
Diekirch	19Mar24	11:12	337.5	many clouds	73.7
Diekirch	18Mar24	11:35	359.7	some clouds	66.5
Diekirch	17Mar24	12:12	320.3	heavy clouds	62.1
Diekirch	15Mar24	12:43	323.0	heavy clouds	88.9
Diekirch	14Mar24	11:51	256.7	many clouds	78.7
Diekirch	13Mar24	13:57	329.4	heavy clouds	70.7
Diekirch	11Mar24	14:44	419.2	many clouds	94.9
Diekirch	10Mar24	11:23	362.0	heavy clouds	76.0
Diekirch	09Mar24	12:27	376.3	light haze	95.3
Diekirch	08Mar24	12:21	333.9	blue sky	83.4
Diekirch	07Mar24	12:06	341.6	some clouds	78.1
Diekirch	06Mar24	13:20	378.0	some clouds	80.0
Diekirch	05Mar24	13:27	401.6	heavy clouds	84.5
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	24Feb24	11:30	462.7	many clouds	90.6
Diekirch	17Feb24	11:10	313.8	many clouds	75.3
Diekirch	13Feb24	13:20	313.5	many clouds	74.2
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.

(**) 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.

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

Total Ozone Thickness 2024