|Name||Hungarian Meteorological Service|
|Address 3||H-1181 Budapest, Gilice tér 39.|
|Organization name||Research Centre for Astronomy and Earth Sciences|
|Last updated date||2020-09-10|
9999-12-31 00:00:00 - 9999-12-31 23:59:59: WMO CO2 X2007
1994-09-01 00:00:00 - 2007-08-09 12:59:59: LI-6251 (Li-Cor Inc.)(NDIR)
2007-08-09 13:00:00 - 9999-12-31 23:59:59: LI-7000 (Li-Cor Inc.)(NDIR)
9999-12-31 00:00:00 - 9999-12-31 23:59:59: 10 (m)
|The basic measuring cycle is two minutes, consisting of one minute flushing and one minute signal integration. Each one minute average is based on 6-7 measurements. The multiport valve steps through the four monitoring levels in eight minutes. Every 32 minutes, after four 8 minutes measuring cycles, the standard gas with the lowest CO2 mixing ratio is selected and analyzed, and we term this measurement a "zero". After every sixth cycle (every 202 minutes) a full four-point calibration is carried out. Reference gases are produced and certified by NOAA CMDL.|
|The basic measuring cycle is two minutes, consisting of one minute flushing and one minute signal integration. Each one minute average is based on 6-7 measurements. The multiport valve steps through the four monitoring levels in eight minutes. Every 32 minutes, after four 8 minutes measuring cycles, the standard gas with the lowest CO2 mixing ratio is selected and analyzed, and we term this measurement a "zero". After every sixth cycle (every 202 minutes) a full four-point calibration is carried out. The "zero" measurements are used to account for any short-term drift of the analyzer due to changes in ambient pressure or temperature. A quadratic response function is fit to each set of calibration gas measurements. The "zero" offset and response function are linearly interpolated in time to obtain values appropriate to calculate CO2 mixing ratio from the instrument response.|
[Hourly] Hourly data are calculated as an arithmetic average from the available data. As a monitoring level is measured in every 8 minutes for 2 minutes (one minute flushing + one minute signal integration), 7 one minute average values are available to calculate the hourly average in an optimum case.
[Daily] During the nights high concentration may build up in the shallow nocturnal boundary layer. The spatial representativeness of these data are low (Haszpra, 1999), and these high values significantly distort the 24-hour average. In trend analyses and several other studies requiring daily data, only the measurements performed during the early afternoo hours, when the vertical mixing of the atmosphere is the most vigorous, are taken into account. The daily CO2 mixing ratio values reported to WDCGG are the averages of the hourly values measured between 12 and 16 h local standard time. The daily data defined and calculated in this way are representative to a significant volume of the planetary boundary layer.
Haszpra, L., 1999: On the representativeness of carbon dioxide measurements. J. of Geophysical Research 104D, 26953-26960.
[Monthly] Monthly data are the monthly averages of the daily (early afternoon - see daily data for explanation) data if the number of the available daily data is >10.
Mixing ratios of CO2 are measured at 10, 48, 82 and 115 m above the ground. Air is pumped through 9.5 mm diameter tubes (Dekoron Type 1300) to a CO2 analyzer located in the TV transmitter building. Diaphragm pumps are used to draw air continuously through each of the tubes from the four monitoring levels at a flow rate of about 2 l/min. After the pump, the air at 40 kPa overpressure enters a glass trap for liquid water which is cooled in a regular household refrigerator, to dry the air to a dew point of 3-4°C. Liquid water is forced out through an orifice at the bottom of each trap.
The four inlet tubes and the standard gases are connected to a computer controlled multi-position valve, that selects which monitoring level or standard gas is sampled by the analyzer. Ambient air flows continuously through the multiport valve so that the system is constantly flushed. The air leaving the multiport valve through its common outlet is further dried to a dew point of about -25°C by passage through a 182 cm long Nafion drier, so that the water vapor interference and dilution effect are less than 0.1 ppm equivalent CO2. The Nafion drier is purged in a counter-flow (100 cm3/min) arrangement using waste sample air that has been further dried by passage through anhydrous CaSO4.
Analysis for CO2 is carried out using an infrared gas analyzer (1994-2007: Li-Cor Inc. model LI-6251; 2007-: Li-Cor Inc. model LI-7000). A constant sample flow rate of 100 cm3/min is maintained by a mass flow controller. The reference cell of the CO2 analyzer is continuously flushed at a flow rate of 5-10 cm3/min with a compressed reference gas of 350 ppm CO2 in synthetic air. Calibration of the analyzer is carried out using four standards spanning 330-440 ppm CO2, that were prepared by NOAA/CMDL.
At the highest monitoring level, 115 m above the ground, wind speed , wind direction and air temperature/humidity sensors are mounted along with the air sampling tube at the end of a 4.4 m long instrument arm. The meteorological instrumentation at 82 m above the ground is similar, but a wind direction sensor is not installed there. At the 48 m level, the flow distortion caused by the larger diameter of the tower has a significant influence on the wind measurements. Therefore, two 2.5 m long instrument arms were mounted on opposite sides of the tower. Anemometers are installed on both arms and a temperature/humidity sensor and air sample inlet tube are mounted only on the north arm. We corrected the measured wind speeds based on a theoretical laminar flow pattern around a cylindrical body using wind direction information from the 115 m level. For measurements at 10 m above the ground, a mast was erected about 70 m from the transmitter building and tower.
For more details see Haszpra et al. (2001).
Wind direction: 0
Wind speed: 1
Relative humidity: 1
Precipitation amount: 0
Air pressure: 0
Air temperature: 1
Dew point temperature: 0
Sea water temperature: 0
Sea surface water temperature: 0
Sea water salinity: 0
Sea surface water salinity: 0
Meteorological data may remain as first provded, even when greenhouse gas data are updated.
|1||Haszpra, L., Barcza, Z., Bakwin, P. S., Berger, B. W., Davis, K. J., Weidinger, T., 2001: Measuring system for the long-term monitoring of biosphere/atmosphere exchange of carbon dioxide. J. of Geophysical Research 106D, 3057-3070.|
|2||Haszpra, L., Barcza, Z., Hidy, D.,Szilagyi, I., Dlugokencky, E., Tans, P., 2008: Trends and temporal variations of major greenhouse gases at a rural site in Central Europe. Atmospheric Environment 42, 8707-8716.|
|3||Haszpra, L., Barcza, Z., 2010: Climate variability as reflected in a regional atmospheric CO2 record. Tellus 62B, 417-426. DOI:10.1111/j.1600-0889.2010.00505.x|
|4||Haszpra, L. (editor), 2011: Atmospheric greenhouse gases: The Hungarian perspective. Springer, Dordrecht - Heidelberg - London - New York. ISBN 978-90-481-9949-5.|
|5||Haszpra, L., Ramonet, M., Schmidt, M., Barcza, Z., Patkai, Z., Tarczay, K., Yver, C., Tarniewicz, J., Ciais, P., 2012. Variation of CO2 mole fraction in the lower free troposphere, in the boundary layer and at the surface. Atmos. Chem. Phys. 12, 8865-8875.|
|6||Haszpra, L., Barcza, Z., Haszpra, T., Patkai, Z., Davis, K.J., 2015. How well do tall-tower measurements characterize the CO2 mole fraction distribution in the planetary boundary layer? Atmos. Meas. Tech. 8, 1657-1671.|