readme95.html

INFO-FILE FOR THE LCD METEO-STATION

This file contains all relevant informations concerning the meteorological station of the LYCEE CLASSIQUE DIEKIRCH (LCD). It is also a LOG-FILE for occurring problems, changes or other important news. These informations will simply be appended to the end of this file.

Please mail your correspondance to: francis.massen@ci.educ.lu

Attention: this file has been replaced by readme.html and stays here only for archiving proposes!



1. Description of the meteorological station

Name:
Meteorological station of the LYCEE CLASSIQUE DIEKIRCH

Address:
LYCEE CLASSIQUE L-9233 DIEKIRCH (Luxembourg, Europe) attn: Prof. Francis Massen, Physics Lab.

Model:
DELTA-T Weatherstation, connected to DL2 datalogger; manufacturer DELTA-T Devices Ltd 128 Low Road, Burwell, GB - Cambridge, CB5 OEJ

Coordinates:

Altitude:
218 meter above sea-level

TIME:
UTC TIME, manually synchronised on DCF77 atomic clock


2. SENSORS (in the order of appearance in the data-file):
state: JUNE 95

  1. AN1 air speed measured by cup-anemometer accuracy 1%; threshhold 0.2 m/s
  2. RG1 rain-fall measured by tipping-bucket device 0.2 mm per tip; expressed in mm per hour
  3. TM1 Logger temperature, NTC sensor, serves as a check for critical high temperatures; disregard!
  4. TM1 Air_Temperature, NTC sensor in louvred enclosure accuracy 0.1 degrees Celsius
  5. %RH Air_Humidity in louvred enclosure accuracy better then 2%
  6. TM1 Soil_Temperature, NTC sensor insertet into brick wall; actually measures temperature of the wall on top at the roof; specifications same as TM1 Air_Temperature
  7. BAR Real local air pressure, NOT REDUCED TO SEA-LEVEL!!! Add 27.3 HPa to get sea-level barometric pressure SCXAN15 sensor from Sensortechnics, accuracy 1-2 HPa
  8. ESR Solar radiation (irradiance) in W/m2; silicon photodiode with reasonably flat spectral response from 400 to 1000 nanometer. Accuracy 1-2% (estim.)
  9. UV_A Ultraviolet (UV-A region) sensor covering the spectrum from 320 to 400 nm. Output in W/m2.Spectral response curve is bell-shaped (slightly asymetric), with maximum 100% relative sensitivity at 370 nm. Bandwidth at -3db (70% rel.sens.) is from 357nm and 378nm; bandwidth at half maximum (50%) is from 352 to 382nm. Please read separate file UV_AB.html
  10. UV_B Ultraviolet (UV_B region) sensor covering the spectrum from 280 to 360nm. Output in W/m2 Spectral response curve is bell-shaped, with maximum 100% relative senssitivity at 313nm. Bandwidth at -3dB (70% rel. sens.) is from 304 to 323nm; bandwidth at half maximum (50%) is from 302 to 327nm (approx.) Please read separate file UV_AB.html
  11. UVB_Bio Ultraviolet Solar 501A sensor measuring the UVB effective radiation, expressed in mMED/h ( milli minimal erythema dose per hour) 1 MED/h = 210 J/(m2*h) = 0.00583 W/m2 effective UV_B irradiance Please read separate file UV_AB.html
  12. UVB_Tin The UVB_Bio sensor must be temperature stabilized at 25 degrees Celsius approx. This signal monitors the temperature of the UVB_Bio sensor
  13. c(CO2) CO2 concentration of the air, expressed in ppm (parts per million; 1 volume% = 10000 ppm) Concentration is NOT reduced to STP conditions! Sensor: self-built NDIR double beam sensor based on the GASGARD 3000 OEM board of Edinburgh Sensors (UK, Edinburgh). Precision = 3%
  14. WV2 Wind_Direction, Windvane (0 degrees means wind blows from North, 90 degrees from East ...). Accuracy better than 2 degrees
  15. Kai Kroneis dew point sensor: voltage of air temperature NTC

    Please read separate file dewpoint.html

  16. KDe Kroneis dew point sensor: voltage of dew point temperature NTC

    Please read separate file dewpoint.html


Sampling for most sensors : 1 per minute, average stored 1 per hour;

except: RG1, CO2 and WV2: 1 measure per hour


3. DATAFILE FORMAT:

The data-files are self-explaining ASCII files, of the type 'comma and " separated columns'; they may readily be imported into (checked!):

Data-files usually cover a whole month, and contain 744 + 8 = 752 lines for 31-days months.

The file TEST_94.DAT is a test-file covering part of March_94


Attention: There are several ERROR-FLAGS which may appear BEFORE


These flags show up mostly on the ESR solar radiation sensor, which gives a slightly negative voltage at night, instead of zero.



4. HISTORY LOG:


  1. 11_Mar_94; 09:00 UTC: start of logging
  2. 18_May_94; 09:00 UTC: installation of aluminium screen to protect datalogger from direct solar radiation
  3. 15_Jun_94; 09:00 UTC: installation of an UV_A and UV_B sensor. Due to malfunction all values from 15_Jun_94 10:00 to 17_Jun_94 09:00 should be discarded. Correct measurements start at 17_Jun_94 10:00. Please read separate file UV_AB.html
  4. JULY_94, AUG_94, SEP_94: due to a hardware problem, raingauge reports 0 mm rain, which was not the case. The global rainfall for these months, as reported by a nearby weatherstation are:
  5. 07_Aug_94: The EMP of a nearby lightning stroke killed the serial interface of the logger. This made communication with a computer impossible, but did not hamper the normal functioning of the weather- station. All values of August and first part of September 94 are ok (except rainfall). The logger was out of action from 15_Sep_94 08:00 up to 14_Oct_94 15:00 (repair could not be done more quickly!) Normal operation resumed the 14th October 1994 at 17:00 UTC
  6. 25_Jan_95: A period of heavy rainfall and high wind gusts shows that the rain-gauge measures too high rainfall when wind velocity exceeds about 5 m/s. This is probably due to wind induced vibrations which provoke a dipping of the water collecting buckets, even if these are empty or not comppletely filled. The values of 22_Jan_95 16:00 to 23_Jan_95 00:00 and 25_Jan_95 18:00 to 26_Jan_95 00:00 corresponding to high wind velocities should be discarded. The raingauge-mounting has been modified the 03_Feb_95 10:00 to correct this problem.
  7. 09_May_95 23:00 UTC: End of logging under previous configuration. Major overhaul of electrical installation. Added UVB_Bio and CO2 sensors
  8. 15_May_95 07:00 UTC: Restart with new configuration
  9. 20_Jun_95 00:00 UTC: CO2 sensor malfunction up to end of month!
  10. 06_Jul_95 08:00 UTC : Power supply malfunction stops logger. No data available up to 14_Jul_95 10:00. From this time on 2 new signals from Kroneis dew point sensor


5. DATA FILES:


  1. MAR94.dat : March 1994; from 11_MAR-94 09:00 UTC to 31_Mar_94 23:00 UTC
  2. APR94.dat : April 1994; max. et minim. values refer to time shown in the header
  3. MAY94.dat : May 1994; .... idem ....
  4. JUN94_1.dat : June 1994; first half of month (01->15 at 08:00) prior to UV sensors installation
  5. JUN94_2.dat : June 1994; second half of month; UV sensors installed
  6. JUL94.dat : July 1994; no rainfall values
  7. AUG94.dat : August 1994; no rainfall values
  8. SEP94.dat : September 1994; only values from 01/09/94 00:00 to 15/09/94 07:00 then logger out of operation until 14/10/94 16:00
  9. OCT94.dat : October 1994; only values from 14/10/94 17:00 on rainfall sensor problem corrected
  10. NOV94.dat : November 1994
  11. DEC94.dat : December 1994
  12. 1994.ZIP : all values from 11_Mar_1994 to 31_Dec_1994, together with README.TXT and UV_AB.TXT files
  13. JAN95.dat : January 1995 ; please read history log concerning rainfall data
  14. FEB95.dat : February 1995
  15. MAR95.dat : March 1995
  16. APR95.dat : April 1995
  17. MAY95_1.dat : May 95, 1-->09 at 23:00; previous configuration
  18. MAY95_2.dat : May 95. 15/05/95 07:00 --> 31/05/95 23:00 new configuration
  19. JUN95.dat : June 1995
  20. JUL95_1.dat: 1 to 6 July 1995, 08:00. No data up to 14_Jul_95 10:00
  21. JUL95_2.dat: 17 July 95 05:43 to 31 July 95 23:45 NO CO2 values; Kroneis Dewpoint sensor active! (but bad values from 29Jul 21:43 on)
  22. AUG95.dat: August 1995; no CO2 values, dewpoint-values regrettably bad!
  23. SEP95.dat: September 1995; partial CO2 values, may be too low. No dew-point-values, sensor in repair!
  24. OCT95.dat: October 1995; CO2 values seem to be too low. We wait for a repaired and new calibrated sensor board. No dew-point-values, sensor still in repair!
  25. NOV95.dat: NEW REPAIRED and CALIBRATED CO2 sensor starts 16 Nov 95 at 10:00 UTC NEW REPAIRED and CALIBRATED DEW POINT sensor starts 23 Nov 95 11:00 UTC >LI>DEC95.dat: December 1995 data. From January 1996 on the history log and other relevant informations will be included in the monthly data file as a ten line header!