These are the news starting 01 Jan 2018
Click here for the news of the previous years.

01 Mar 18 1. Upload of the February 2018 data into the  data archive.
Attention: there are no data from 26/02 08:00 to 27/02 08:30, due to the logger breakdown. This is a very rare event in the more than 20 years of meteoLCD, but alas not an impossible one!
2. The plots of Air Quality now show in the title "good if < 200). This qualifier corresponds to the UK norm of combined O3 and NO2 concentration; if that number is below 200 ug/m3, the situation corresponds to the 2nd level of the "GOOD" (=green) category, which holds 3 levels.
27 Feb 18 1. The datalogger computer was unable to load it's system (XPe), no obvious cause found. Restarted at 07:28 UTC today.
2. There is a second much more severe problem: the datalogger has corrupted readings, probably caused by my yesterday tests with reading dual analog signals (voltage and intensity) of the Cairsens O3&NO2 into the logger (problem of channel overload from inexistent galvanic separation, obscure common ground problem....).
3. I downloaded all data from the logger, emptied memory, re-installed configuration and programmed to restart logging at 09:00. The first correct data (graphs and numbers) should be available at 09:45.
26 Feb 18 There is a breakdown of our datalogger computer, since this morning around 07:30 UTC. Will look at the problem tomorrow morning...Sorry!
19 Feb 18 The meteoLCD crew has written a short paper comparing our 2017 total ozone column measurements with those made at the RMI, Uccle (close to Brussels). Uccle is a world famous research facility for TOC measurements, and has one of the longest data series available. Our Diekirch measurements made with vastly less expensive instruments are quite satisfying. Read the paper here.
01 Feb 18 1. Upload of January 2018 data into data archive. Please read metadata (file header) very carefully!
2. Attention: this is the last month with [O3] readings from the O341M sensor, which will be shut down now. The overlap with simultaneous measurements by the CAIRSENS O3&NO2 allows a comparison of the two measurement series, and most important, about their temporal synchronicity. A quick check shows a very satisfying behaviour of the CAIRSENS device, so that we plan to add a second CAIRSENS measuring only NO2, which would give [O3] by simple difference between the two CAIRSENS readings.
A real serious investigation on the CAIRSENS sensor can be found here (with highlighting added).
11 Jan 18 1. Work on the "trends" section finished. Some future editing is probable, as some datasets for comparison (like Uccle's TOC at WOUDC) are still uncomplete.
2. A first quick comparison of the measurements of our new CAIRSENS Air Quality sensor and the old ozone sensor shows a quite satisfying correlation.
04 Jan 18 Work on the "trends" section has started. 7 parameters out of 13 have been updated. This is not a fast and quick automatically done procedure, but remains tedious work, so be patient waiting for the final update.
03 Jan 18 Installation of the new CAIRSENS O3&NO2 mini-sensor (09:30)

This electrochemical (amperometric) sensor measures the combined O3 and NO2 concentration, which we call AQ (for Air Quality). The new measurements are on channel 16 (the former NOx channel). Channel 17 (former NO) should be ignored!

Picture shows our Stevenson hut with the Vaisala CO2 and the Cairsens O3&NO2 sensors (click for full size).

Using this sensor is sort of an experience. Only time will tell if it lives up to its promises (no calibration needed, minimal maintenance, acceptable precision).

The graphs of today will be a bit messy!

The purchase of the new sensor has been financed by our sponsor AALCD (Amicale des Anciens du Lycée Classique Diekirch).

02 Jan 18 Upload into data archive of :
1. yearly Excel file with 2017 measurements and elementary statistics : 2017_only.xls
2. summary Excel file with statistics 1998-2017: meteoLCDstats_1998_2017.xls
3. Corrected/edited the "monthlys" worksheet of the 2016_only.xls file.
4. NOx/NO2 sensor from Environnement SA (AC31M) definitively shut off.
This is the end of our traditional atmospheric gas measurements using big and expensive equipement. The O341M sensor for ground ozone will continue for a couple of weeks to allow comparison with the new equipment, before also going into retirement!
01 Jan 18 1. The usual dogs-dinner in the 7days plot due to Gnuplot problems with handling previous and new year (the logger files do not contain the year number). This will be self healing in the the next 7 days.
2. Upload dec17.dat and (= all 2017 .dat files concatenated with headers, and zipped) into data archive.


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