Total Ozone Thickness

Location	Date	UTC Time	Thickness [DU]	Sky Condition	Ozone&NO2 [ug/m³] **
Diekirch	31Dec21	12:12	265.7	some clouds	51.5
Diekirch	22Dec21	12:12	298.6	light haze	54.8
Diekirch	21Dec21	12:09	286.8	blue sky	74.9
Diekirch	19Dec21	12:11	288.5	some clouds	54.6
Diekirch	17Dec21	12:11	290.2	some clouds	61.4
Diekirch	16Dec21	12:13	283.2	some clouds	64.7
Diekirch	11Dec21	13:20	274.3	heavy clouds	61.2
Diekirch	25Nov21	12:32	291.7	light haze	57.5
Diekirch	23Nov21	11:20	297.4	blue sky	70.6
Diekirch	20Nov21	12:37	280.2	many clouds	65.6
Diekirch	11Nov21	12:09	270.0	blue sky	53.4
Diekirch	10Nov21	11:49	283.7	light haze	93.8
Diekirch	09Nov21	12:43	274.4	blue sky	66.8
Diekirch	06Nov21	12:04	249.4	some clouds	57.6
Diekirch	04Nov21	12:40	334.3	heavy clouds	48.9
Diekirch	03Nov21	13:42	325.3	heavy clouds	56.7
Diekirch	02Nov21	12:21	308.0	some clouds	67.5
Diekirch	01Nov21	12:19	304.0	some clouds	82.2
Diekirch	29Oct21	11:04	255.0	light haze	87.2
Diekirch	27Oct21	12:11	239.0	heavy clouds	66.0
Diekirch	26Oct21	11:06	275.1	heavy clouds	73.8
Diekirch	25Oct21	11:06	252.4	light haze	66.9
Diekirch	24Oct21	10:53	252.5	blue sky	57.1
Diekirch	22Oct21	11:29	268.9	some clouds	72.6
Diekirch	21Oct21	11:16	294.2	many clouds	78.2
Diekirch	19Oct21	12:42	236.3	some clouds	62.7
Diekirch	18Okt21	11:15	266.2	very hazy	45.2
Diekirch	17Oct21	11:51	269.9	heavy clouds	79.8
Diekirch	16Oct21	11:18	267.4	blue sky	71.2
Diekirch	15Oct21	11:33	281.6	some clouds	58.9
Diekirch	14Oct21	11:22	269.4	some clouds	81.1
Diekirch	13Oct21	13:03	279.2	many clouds	66.5
Diekirch	11Oct21	11:02	278.5	many clouds	87.0
Diekirch	08Oct21	11:01	247.4	blue sky	90.3
Diekirch	07Oct21	09:27	264.8	many clouds	59.6
Diekirch	05Oct21	11:54	285.4	heavy clouds	74.7
Diekirch	04Oct21	11:16	296.3	heavy clouds	70.8
Diekirch	02Oct21	11:57	273.9	many clouds	69.5
Diekirch	01Oct21	10:22	286.8	many clouds	74.0
Diekirch	30Sep21	10:17	295.5	many clouds	56.0
Diekirch	29Sep21	12:21	286.6	some clouds	94.4
Diekirch	25Sep21	10:48	278.5	blue sky	47.4
Diekirch	23Sep21	10:38	280.9	many clouds	74.6
Diekirch	22Sep21	11:03	277.6	some clouds	97.3
Diekirch	20Sep21	10:01	294.1	many clouds	73.2
Diekirch	19Sep21	11:57	286.0	many clouds	91.4
Diekirch	18Sep21	11:18	275.2	many clouds	112.1
Diekirch	17Sep21	09:25	287.5	some clouds	54.8
Diekirch	14Sep21	09:34	283.4	many clouds	87.2
Diekirch	13Sep21	11:48	270.9	many clouds	134.1
Diekirch	04Sep21	12:34	288.6	blue sky	141.6
Diekirch	03Sep21	12:30	278.1	blue sky	120.9
Diekirch	02Sep21	11:00	299.4	blue sky	122.7
Diekirch	01Sep21	11:00	310.5	many clouds	99.5
Diekirch	31Aug21	11:45	316.8	many clouds	110.4
Diekirch	25Aug21	11:07	301.7	many clouds	116.0
Diekirch	24Aug21	13:00	315.1	many clouds	113.8
Diekirch	23Aug21	11:10	308.0	blue sky	98.8
Diekirch	22Aug21	09:45	315.0	many clouds	67.0
Diekirch	21Aug21	10:05	311.6	some clouds	80.2
Diekirch	16Aug21	11:03	321.2	many clouds	72.3
Diekirch	15Aug21	11:05	300.7	many clouds	86.3
Diekirch	14Aug21	10:50	297.4	some clouds	109.4
Diekirch	13Aug21	12:55	283.1	many clouds	105.8
Diekirch	12Aug21	11:30	303.6	some clouds	114.5
Diekirch	11Aug21	11:40	298.9	many clouds	95.0
Diekirch	09Aug21	10.07	324.2	many clouds	79.4
Diekirch	08Aug21	11:06	345.1	many clouds	71.2
Diekirch	07Aug21	10:30	319.5	many clouds	69.3
Diekirch	06Aug21	10:25	337.4	many clouds	68.1
Diekirch	05Aug21	10:15	337.7	many clouds	89.9
Diekirch	04Aug21	11:40	338.5	many clouds	77.9
Dielirch	28Jul21	10:17	339.2	many clouds	68.8
Diekirch	26Jul21	10:12	350.8	many clouds	90.7
Diekirch	25Jul21	11:10	340.9	many clouds	64.3
Diekirch	24Jul21	12:00	348.0	many clouds	82.0
Diekirch	23Jul21	10:41	308.7	many clouds	135.6
Diekirch	22Jul21	11:15	323.1	many clouds	125.5
Diekirch	21Jul21	12:20	309.9	some clouds	119.2
Diekirch	20Jul21	10:05	306.0	some clouds	98.8
Diekirch	19Jul21	13:38	290.4	some clouds	90.3
Diekirch	17Jul21	12:15	309.8	many clouds	103.3
Diekirch	11Jul21	11:27	311.2	some clouds	78.9
Diekirch	10Jul21	11:22	307.2	heavy clouds	100.2
Diekirch	07Jul21	11:11	330.2	many clouds	88.1
Diekirch	06Jul21	10:12	324.2	heavy clouds	77.0
Diekirch	01Jul21	14:00	325.3	heavy clouds	87.9
Diekirch	28Jun21	11:11	311.5	many clouds	112.9
Diekirch	26Jun21	10:56	324.5	some clouds	108.3
Diekirch	25Jun21	11:26	321.3	light haze	112.23
Diekirch	21Jun21	11:17	318.4	heavy clouds	95.6
Diekirch	20Jun21	11:31	317.4	some clouds	95.3
Diekirch	19Jun21	09:34	308.8	some clouds	105.4
Diekirch	18Jun21	11:40	317.2	some clouds	111.7
Diekirch	17Jun21	11:25	316.3	light haze	147.3
Diekirch	16Jun21	11:19	311.0	some clouds	147.4
Diekirch	15Jun21	10:30	315.8	light haze	160.6
Diekirch	14Jun21	11:17	307.1	blue sky	101.7
Diekirch	13Jun21	11:08	302.5	blue sky	94.6
Diekirch	11Jun21	11:06	303.9	some clouds	109.7
Diekirch	10Jun21	11:17	317.3	some clouds	121.2
Diekirch	09Jun21	12:09	328.3	heavy clouds	107.6
Diekirch	08Jun21	09:57	324.0	heavy clouds	61.2
Diekirch	07Jun21	10:59	323.3	heavy clouds	130.9
Diekirch	02Jun21	10:38	337.4	some clouds	162.8
Diekirch	01Jun21	10:52	326.3	blue sky	145.0
Diekirch	31May21	11:30	317.8	blue sky	126.0
Diekirch	30May21	10:28	332.4	some clouds	105.8
Diekirch	29May21	10:50	347.0	many clouds	112.4
Diekirch	28May21	10:40	328.6	many clouds	85.1
Diekirch	26May21	12:08	392.6	many clouds	88.3
Diekirch	17May21	10:40	368.1	many clouds	48.9
Diekirch	16May21	10:20	374.9	many clouds	53.5
Diekirch	14May21	12:20	358.6	heavy clouds	90.8
Diekirch	12May21	11:19	360.6	many clouds	103.8
Diekirch	09May21	11:33	306.3	blue sky	115.5
Diekirch	08May21	14:10	320.1	very hazy	83.5
Diekirch	07May21	11:03	389.1	some clouds	92.5
Diekirch	05May21	10:12	393.4	some clouds	77.5
Diekirch	04May21	11:27	337.9	heavy clouds	68.6
Diekirch	02May21	11:23	378.9	heavy clouds	94.7
Diekirch	01May21	11:20	356.3	very hazy	99.1
Diekirch	30Apr21	11:04	366.5	very hazy	99.7
Diekirch	29Apr21	11:06	400.3	some clouds	112.6
Diekirch	28Apr21	11:02	362.3	blue sky	125.4
Diekirch	27Apr21	11:13	386.3	blue sky	98.5
Diekirch	26Apr21	10:25	363.4	blue sky	87.5
Diekirch	25Apr21	12:32	293.5	blue sky	99.4
Diekirch	24Apr21	11:06	293.4	light haze	105.1
Diekirch	23Apr21	11:17	326.3	blue sky	89.1
Diekirch	22Apr21	10:31	355.8	light haze	91.2
Diekirch	21Apr21	11:35	333.6	heavy clouds	126.3
Diekirch	20Apr21	10:05	358.5	some clouds	82.2
Diekirch	19Apr21	10:51	394.4	many clouds	78.3
Diekirch	18Apr21	09:18	395.2	some clouds	58.9
Diekirch	17Apr21	11:27	376.5	light haze	91.9
Diekirch	16Apr21	11:07	393.6	heavy clouds	83.7
Diekirch	15Apr21	11:00	437.8	many clouds	91.9
Diekirch	14Apr21	13:17	461.2	heavy clouds	98.5
Diekirch	13Apr21	10:57	427.2	heavy clouds	89.1
Diekirch	12Apr21	12:41	411.7	some clouds	96.2
Diekirch	09Apr21	11:10	366.1	hazy	91.1
Diekirch	08Apr21	12:23	344.8	many clouds	88.3
Diekirch	06Apr21	09:17	420.1	many clouds	78.2
Diekirch	04Apr21	15:19	361.7	light haze	111.1
Diekirch	03Apr21	11:33	362.5	some clouds	109.6
Diekirch	02Apr21	11:07	357.5	blue sky	88.9
Diekirch	01Apr21	11:02	308.8	light haze	133.1
Diekirch	31Mar21	11:14	335.8	blue sky	53.2
Diekirch	30Mar21	11:11	337.8	blue sky	69.0
Diekirch	29Mar21	11:03	333.8	blue sky	52.5
Diekirch	28Mar21	11:21	340.2	many clouds	53.8
Diekirch	27Mar21	11:22	350.6	heavy clouds	41.9
Diekirch	26Mar21	12:07	341.7	heavy clouds	50.5
Diekirch	25Mar21	11:57	353.3	heavy clouds	44.3
Diekirch	24Mar21	12:18	307.9	blue sky	35.1
Diekirch	23Mar21	12:05	336.8	blue sky	36.4
Diekirch	21Mar21	13:41	317.8	heavy clouds	40.6
Diekirch	20Mar21	12:09	334.1	blue sky	39.3
Diekirch	19Mar21	12:07	408.2	heavy clouds	47.1
Diekirch	18Mar21	12:29	372.7	some clouds	41.9
Diekirch	17Mar21	12:10	361.8	many clouds	42.3
Diekirch	15Mar21	11:18	409.4	many clouds	48.9
Diekirch	14Mar21	12:28	440.3	heavy clouds	36.4
Diekirch	13Mar21	11:14	387.7	heavy clouds	54.1
Diekirch	12Mar21	11:17	396.5	heavy clouds	44.8
Diekirch	11Mar21	13:15	304.7	heavy clouds	45.1
Diekirch	10Mar21	12:43	311.1	many clouds	43.8
Diekirch	08Mar21	11:04	368.7	some clouds	37.2
Diekirch	07Mar21	11:28	356.0	blue sky	40.2
Diekirch	06Mar21	11:12	345.7	blue sky	42.4
Diekirch	05Mar21	12:55	318.7	heavy clouds	32.6
Diekirch	04Mar21	14:31	314.6	light haze	37.7
Diekirch	03Mar21	09:11	335.6	hazy	15.6
Diekirch	02Mar21	12:20	339.2	blue sky	30.8
Diekirch	01Mar21	12:01	347.3	blue sky	43.0
Diekirch	28Feb21	11:32	310.3	blue sky	48.3
Diekirch	27Feb21	11:40	277.8	many clouds	52.3
Diekirch	25Feb21	11:53	255.4	light haze	21.5
Diekirch	24Feb21	11:24	260.8	light haze	29.6
Diekirch	23Feb21	12:06	301.2	light haze	47.4
Diekirch	22Feb21	12:55	277.9	hazy	24.9
Diekirch	21Feb21	12:21	281.4	blue sky	62.5
Diekirch	20Feb21	12:19	282.5	light haze	52.5
Diekirch	19Feb21	11:48	325.3	heavy clouds	38.4
Diekirch	16Feb21	14:10	300.0	heavy clouds	28.0
Diekirch	15Feb21	13:38	310.3	heavy clouds	13.5
Diekirch	14Feb21	11:36	334.8	blue sky	33.9
Diekirch	12Feb21	12:17	324.5	blue sky	41.1
Diekirch	11Feb21	12:07	318.0	many clouds	38.4
Diekirch	10Feb21	12:18	329.3	blue sky	39.9
Diekirch	04Feb21	12:06	336.2	many clouds	50.1
Diekirch	03Feb21	13:28	358.2	heavy clouds	60.4
Diekirch	02Feb21	12:30	324.3	heavy clouds	35.1
Diekirch	29Jan21	11:52	382.8	heavy clouds	58.1
Diekirch	26Jan21	12:44	329.0	heavy clouds	41.1
Diekirch	24Jan21	10:41	368.0	many clouds	43.3
Diekirch	22Jan21	12:09	325.1	heavy clouds	47.7
Diekirch	21Jan21	12:46	291.3	heavy clouds	49.9
Diekirch	20Jan21	12:52	271.3	some clouds	38.8
Diekirch	17Jan21	12:10	333.0	heavy clouds	33.8
Diekirch	15Jan21	11:57	295.9	some clouds	32.7
Diekirch	13Jan21	12:43	262.8	many clouds	43.5
Diekirch	11Jan21	12:28	264.3	hazy	23.8
Diekirch	09Jan21	12:36	294.4	many clouds	28.8

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 2021