Total Ozone Thickness

Location	Date	UTC Time	Thickness [DU]	Sky Condition	Ozone&NO2 [ug/m³] **
Diekirch	31Dec23	13:42	303.4	heavy clouds	72.1
Diekirch	28Dec23	11:10	286.2	heavy clouds	69.2
Diekirch	26Dec23	12:37	260.6	heavy clouds	76.7
Diekirch	16Dec23	11:11	264.1	blue sky	49.2
Diekirch	15Dec23	13:03	275.0	some clouds	27.6
Diekirch	13Dec23	12:27	311.5	some clouds	66.1
Diekirch	11Dec23	13:17	281.3	heavy clouds	71.5
Diekirch	07Dec23	12:19	273.3	heavy clouds	40.1
Diekirch	06Dec23	13:26	278.7	some clouds	56.3
Diekirch	03DEc23	12:43	313.3	hazy	40.2
Diekirch	25Nov23	11:46	318.5	heavy clouds	58.4
Diekirch	22Nov23	12:07	242.9	some clouds	46.9
Diekirch	21Nov23	12:52	285.9	many clouds	56.5
Diekirch	20Nov23	11:10	295.9	heavy clouds	63.9
Diekirch	19Nov23	11:09	274.3	some clouds	79.4
Diekirch	17Nov23	11:10	313.0	heavy clouds	63.0
Diekirch	15Nov23	13:02	336.0	many clouds	71.5
Diekirch	08Nov23	12:05	337.6	heavy clouds	70.8
Diekirch	07Nov23	11:44	353.7	heavy clouds	72.5
Diekirch	06Nov23	13:23	320.3	heavy clouds	67.0
Diekirch	05Nov23	14:39	280.1	heavy clouds	64.5
Diekirch	03Nov23	11:18	380.5	heavy clouds	62.7
Diekirch	02Nov23	13:16	298.5	heavy clouds	79.1
Diekirch	01Nov23	10:08	283.4	heavy clouds	54.9
Diekirch	31Oct23	09:14	345.3	many clouds	70.3
Diekirch	27Oct23	11:08	288.5	heavy clouds	72.4
Diekirch	24Oct23	14:11	290.6	some clouds	70.1
Diekirch	21Oct23	10:43	283.9	some clouds	83.2
Diekirch	17Oct23	12:34	269.4	some clouds	50.5
Diekirch	16Oct23	11:17	272.3	blue sky	68.3
Diekirch	08Oct23	11:52	239.6	some clouds	71.3
Diekirch	07Oct23	11:58	237.8	some clouds	80.6
Diekirch	06Oct23	11:02	263.6	some clouds	54.7
Diekirch	04Oct23	12:00	299.0	many clouds	64.3
Diekirch	02Oct23	10:30	266.6	some clouds	48.3
Diekirch	01Oct23	12:14	266.8	blue sky	87.4
Diekirch	30Sep23	12:05	268.9	some clouds	77.5
Diekirch	28Sep23	10:43	280.1	some clouds	74.2
Diekirch	26Sep23	10:32	269.8	blue sky	48.8
Diekirch	25Sep23	10:30	264.7	blue sky	62.4
Diekirch	24Sep23	11:50	263.3	blue sky	77.6
Diekirch	22Sep23	11:58	315.5	many clouds	71.8
Diekirch	21Sep23	12:10	269.7	many clouds	75.5
Diekirch	19Sep23	10:20	280.7	many clouds	64.2
Diekirch	25Aug23	14:41	259.8	many clouds	101.7
Diekirch	23Aug23	10:40	277.3	some clouds	126.1
Diekirch	22Aug23	14:35	261.8	some clouds	125.5
Diekirch	20Aug23	08:20	277.0	some clouds	52.2
Diekirch	18Aug23	14:02	283.4	some clouds	118.0
Diekirch	17Aug23	12:23	297.8	some clouds	106.9
Diekirch	14Aug23	14:47	288.6	many clouds	87.0
Diekirch	24Jul23	12:10	333.8	many clouds	69.7
Diekirch	22Jul23	11:04	353.8	many clouds	106.7
Diekirch	21Jul23	11:40	350.3	many clouds	103.7
Diekirch	19Jul23	09:53	328.0	some clouds	117.2
Diekirch	18Jul23	10:05	335.9	many clouds	114.7
Diekirch	16Jul23	14:00	303.1	many clouds	94.1
Diekirch	15Jul23	10:03	332.7	many clouds	54.5
Diekirch	12Jul23	11:08	313.3	many clouds	84.2
Diekirch	11Jul23	11:17	303.1	blue sky	135.7
Diekirch	09Jul23	11:07	315.5	very hazy	149.6
Diekirch	08Jul23	12:26	306.8	some clouds	153.2
Diekirch	07Jul23	12:52	321.9	light haze	145.3
Diekirch	06Jul23	10:40	340.5	some clouds	92.1
Diekirch	05Jul23	11:08	357.4	heavy clouds	78.1
Diekirch	04Jul23	13:00	321.1	some clouds	97.3
Diekirch	03Jul23	11:22	311.3	heavy clouds	100.2
Diekirch	30Jun23	11:14	329.4	very hazy	101.2
Diekirch	29Jun23	10:26	309.0	very hazy	103.7
Diekirch	28Jun23	14:34	299.2	many clouds	119.7
Diekirch	27Jun23	11:46	318.3	heavy clouds	116.8
Diekirch	26Jun23	14:57	306.2	some clouds	126.5
Diekirch	25Jun23	12:50	299.6	blue sky	168.9
Diekirch	24Jun23	11:40	340.2	some clouds	155.7
Diekirch	23Jun23	12:27	311.7	some clouds	130.1
Diekirch	22Jun23	10:19	319.9	many clouds	91.6
Diekirch	21Jun23	11:16	315.8	many clouds	139.0
Diekirch	20Jun23	11:20	316.6	some clouds	147.1
Diekirch	19Jun23	14:56	315.1	light haze	137.3
Diekirch	17Jun23	11:41	338.7	light haze	191.1
Diekirch	16Jun23	11:18	352.0	blue sky	165.2
Diekirch	15Jun23	11:10	354.5	some clouds	145.6
Diekirch	14Jun23	11:21	352.3	blue sky	147.1
Diekirch	13Jun23	11:38	342.7	blue sky	160.5
Diekirch	12Jun23	10:42	329.5	many clouds	160.7
Diekirch	10Jun23	12:20	339.9	many clouds	159.2
Diekirch	07Jun23	09:33	378.3	many clouds	130.3
Diekirch	05Jun23	12:33	353.0	some clouds	139.9
Diekirch	04Jun23	12:53	351.7	blue sky	128.3
Diekirch	30May23	12:32	323.5	blue sky	120.9
Diekirch	28May23	12:30	338.5	blue sky	123.6
Diekirch	27May23	12:43	344.3	blue sky	108.8
Diekirch	25May23	10:18	346.1	blue sky	87.4
Diekirch	24May23	10:24	379.0	blue sky	80.0
Diekirch	22May23	10:30	328.3	some clouds	86.3
Diekirch	19May23	11:20	355.7	some clouds	97.4
Diekirch	18May23	11:11	350.2	blue sky	88.6
Diekirch	17May23	13:18	359.9	some clouds	91.8
Diekirch	16May23	11:19	351.3	heavy clouds	76.3
Diekirch	15May23	11:04	355.7	some clouds	122.7
Diekirch	14May23	08.55	351.7	blue sky	77.5
Diekirch	13May23	11:03	357.3	some clouds	107.6
Diekirch	12May23	13:10	330.5	many clouds	78.5
Diekirch	08May23	11:07	329.7	some clouds	87.6
Diekirch	07May23	11:16	334.1	heavy clouds	100.2
Diekirch	05May23	12:07	358.2	heavy clouds	76.6
Diekirch	04May23	11:20	340.0	light haze	103.6
Diekirch	03May23	11:28	339.5	blue sky	93.4
Diekirch	02May23	10:30	351.2	many clouds	76.0
Diekirch	30Apr23	10:04	317.7	many clouds	89.2
Diekirch	27Apr23	11:30	320.8	hazy	70.9
Diekirch	26Apr23	11:21	333.3	many clouds	78.1
Diekirch	25Apr23	11:19	378.0	heavy clouds	77.4
Diekirch	24Apr23	14:37	362.6	heavy clouds	83.7
Diekirch	20Apr23	12:33	390.0	many clouds	80.3
Diekirch	18Apr23	11:28	391.5	many clouds	73.0
Diekirch	16Apr23	12:12	377.3	many clouds	54.1
Diekirch	14Apr23	10:15	386.3	some clouds	80.3
Diekirch	12Apr23	11:30	354.9	many clouds	69.8
Diekirch	11Apr23	10:25	343.3	many clouds	82.0
Diekirch	09Apr23	09:30	364.2	many clouds	44.4
Diekirch	04Apr23	12:35	352.2	many clouds	73.3
Diekirch	03Apr23	11:35	383.8	many clouds	79.3
Diekirch	31Mar23	10:50	367.3	heavy clouds	76.7
Diekirch	30Mar23	11:33	337.1	many clouds	92.2
Diekirch	29Mar23	10:56	327.1	many clouds	54.7
Diekirch	28Mar23	11:12	340.2	some clouds	73.3
Diekirch	27Mar23	10:08	368.3	many clouds	71.2
Diekirch	26Mar23	11:13	381.2	many clouds	88.6
Diekirch	25Mar23	12:08	350.1	some clouds	84.4
Diekirch	24Mar23	11:02	328.3	some clouds	93.8
Diekirch	22Mar23	12:02	319.9	heavy clouds	82.7
Diekirch	18Mar23	13:06	346.9	heavy clouds	70.0
Diekirch	17Mar23	12:48	325.7	heavy clouds	74.5
Diekirch	16Mar23	12:01	327.2	light haze	75.8
Diekirch	15Mar23	12:30	358.6	many clouds	72.7
Diekirch	14Mar23	11:07	362.8	heavy clouds	73.3
Diekirch	11Mar23	12:08	376.8	many clouds	66.4
Diekirch	07Mar23	13:18	393.4	heavy clouds	53.1
Diekirch	03Mar23	12:05	352.6	blue sky	55.0
Diekirch	02Mar23	12:03	368.7	blue sky	61.9
Diekirch	01Mar23	12:01	329.4	blue sky	66.7
Diekirch	28Feb23	12:42	312.9	many clouds	56.9
Diekirch	27Feb23	11:02	336.5	blue sky	64.7
Diekirch	24Feb23	11:30	365.3	blue sky	67.4
Diekirch	22Feb23	11:02	323.5	some clouds	54.3
Diekirch	21Feb23	10:43	319.5	blue sky	29.5
Diekirch	20Feb23	10:45	288.2	some clouds	64.0
Diekirch	15Feb23	12:07	272.1	many clouds	30.2
Diekirch	14Feb23	14:35	230.4	many clouds	48.5
Diekirch	13Feb23	11:28	225.6	some clouds	53.9
Diekirch	10Feb23	15:00	233.3	hazy	52.2
Diekirch	09Feb23	12:51	296.9	light haze	49.2
Diekirch	08Feb23	10:49	280.0	blue sky	54.1
Diekirch	07Feb23	12:27	256.9	blue sky	53.6
Diekirch	06Feb23	11:59	266.3	blue sky	63.9
Diekirch	05Feb23	10:45	323.8	many clouds	74.1
Diekirch	02Feb23	12:59	318.5	heavy clouds	69.6
Diekirch	01Feb23	12:44	334.5	heavy clouds	72.1
Diekirch	30Jan23	12:08	264.9	some clouds	47.4
Diekirch	29Jan23	12:10	272.1	light haze	38.9
Diekirch	21Jan23	12:36	370.6	light haze	59.7
Diekirch	18Jan23	12:16	465.2	light haze	48.4
Diekirch	17Jan23	11:16	399.1	some clouds	57.6
Diekirch	15Jan23	09:54	371.7	many clouds	83.3
Diekirch	13Jan23	10:31	342.1	many clouds	83.6
Diekirch	11Jan23	14:00	295.8	heavy clouds	81.9
Diekirch	05Jan23	12:53	298.1	many clouds	73.3
Diekirch	03Jan23	12:23	370.4	many clouds	73.8

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.
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 2023