Hyytiälä database
Tables in the new database
HYY_META: meteorological, gas concentration and soil data
HYY_EDDY233: the primary flux data measured in the mast / tall tower at 23 m height
HYY_EDDYTOW: secondary flux data from radiation tower
HYY_EDDYSUB: subcanopy fluxes
HYY_TREE: tree gas exchange, sapflow, diameter change, fluorescence
HYY_DMPS: particles
HYY_SLOW: infrequent measurements (e.g. snow depth, dendrometers)
How to access the databaseSMEAR database
The symbols used in the database
Directly copied from the text files, slightly out of date ... 
Mast data
time YYYYMMDDHHMMSS (beginning of averaging period, UTC+2)
Td dew point in C-units
Pamb air pressure in hPa
T air temperature in C
WSU wind speed in m/s measured with ultrasonic anemometer
WS wind speed in m/s measured with cup anemometer
WD wind direction (average of above-tree-top levels) in degrees measured with wind vane/ultrasonic anemometer
WDU wind direction in degrees measured with ultrasonic anemometer
NO nitrogen monoxide concentration in ppb-units
NOx nitrogen monoxide + nitrogen dioxide concentration in ppb-units
O3 ozone concentration in ppb-units
SO2 sulphur dioxide concentration in ppb-units
H2O water vapour concentration in ppth-units (part per thousand)
CO2 carbon dioxide concentration in ppm-units
H2S hydrogen sulphide concentrations in ppb-units
RHURAS relative humidity in % calculated using H2O conc. and T data
CO carbon monoxide concentration in ppb-units
RHTd relative humidity in % calculated using dew point data and T data
PTG potential temperature gradient in C/m
740 measurement level 74.0 m above Mast base
672 measurement level 67.2 m above Mast base
504 measurement level 50.4 m above Mast base
336 measurement level 33.6 m above Mast base
168 measurement level 16.8 m above Mast base
84 measurement level 8.4 m above Mast base
42 measurement level 4.2 m above Mast base
23 measurement level 23 m above Mast base
0 measurement level 0 m above Mast base
Mast base is slightly above the surrounding terrain.
Code -999 is used to indicate missing data.
The values of the variables are calculated 1-minute averages. Of the measurement levels
4.2 m and 8.4 m level represent under-tree-top layer, 16.8 m level is the first above-tree-top layer
and 67.2 m/74.0 m level is often above the surface layer at the measurement site.
Wind direction (WD) is measured with wind vane (W200P, Vector Instruments, Rhyl, Clwyd, UK) (threshold 0.6 m/s) until 20030904 and
with ultrasonic anemometer (Ultrasonic anemometer 2D, Adolf Thies GmbH, Göttingen, Germany) beginning 20030905.
Wind speed (WS) is measured with cup anemometer (A101M/L, Vector Instruments, Rhyl, Clwyd, UK) (threshold 0.15 m/s) until 20030904 and
with ultrasonic anemometer (Ultrasonic anemometer 2D, Adolf Thies GmbH, Göttingen, Germany) beginning 20030905. At level
33.6 m wind speed is measured also with cup anemometer even after 20030904.
Temperature (T) is measured with PT-100 resistance thermometers, which are protected from solar radiation and ventilated by fans.
Air pressure (Pamb) is measured from inside the measurement building with a barometer (DPI260, Druck, Leicester, UK).
Dew point (Td) is measured with a chilled mirror sensor (M4 Dew point monitor, General Eastern, Woburn, MA, USA).
NO and NOx (NO + NO2) concentrations are measured with one chemiluminescence analyser (TEI 42C TL, Thermo Environmental, Franklin, MA, USA).
NO2-concentration can be calculated as difference (NOx-NO). Note! Between 1.1.1996 - 27.2.2007 a molybdenum converter was used to convert
NO2 --> NO. This method also converts other reactive nitrogen oxide species (e.g. PAN) to NO and thus the NOx signal should
be considered as an upper estimate for NO+NO2 concentration. Starting 1.3.2007 an NO2 specific photolytic converter
(Blue Light Converter, Droplet Measurement Technologies, Boulder, CO, USA) was taken into use removing this interference
from the NOx signal.
O3 concentration is measured with one ultraviolet light absorption analyser (TEI 49C, Thermo Environmental, Franklin, MA, USA).
H2O concentration is measured with one infrared light absorption analyser (URAS 4 H2O, Hartmann & Braun, Frankfurt am Main, Germany).
RHURAS at a given measurement level is calculated as the ratio between the measured H2O concentration (converted to vapour
pressure) and the saturation vapour pressure calculated from the measured air temperature.
SO2 concentration is measured with one fluorescence analyser (TEI 43C TL, Thermo Environmental, Franklin, MA, USA).
H2S concentration is measured with one fluorescence analyser (TEI 43 BS, Thermo Environmental, Franklin, MA, USA) and a thermal oxidizer
(CDN-101, CdNova, Burnaby, British Columbia, Canada.
CO2 concentration is measured with one infrared light absorption analyser (URAS 4 CO2, Hartmann & Braun, Frankfurt am Main, Germany).
CO concentration is measured with one infrared ligth absorption analyser (HORIBA APMA 360, Horiba, Kyoto, Japan).
RHTd23 is calculated from the measured dew point temperature and the average of 16.8 m & 33.6 m air temperatures.
PTG is calculated from 67.2 m and 16.8 m air temperature and H2O concentration data
Radiation and precipitation
time YYYYMMDDHHMMSS (beginning of averaging period, UTC+2)
UV-A ultraviolet radiation in wavelength range 0.32 - 0.40 um in units W/m2
UV-B ultraviolet radiation in wavelength range 0.28 - 0.32 um in units W/m2
diffPAR diffuse photosynthetically active radiation (wavelength range 400-700 nm) in units umol/(m2s)
diffGlob diffuse solar radiation in wavelength range 0.30 - 4.8 um in units W/m2
Net net radiation in wavelength range 0.30 - 40 um in units W/m2 (+ sign means ground gains heat)
RGlob reflected solar radiation in wavelength range 0.30 - 4.8 um in units W/m2
Glob solar radiation in wavelength range 0.30 - 4.8 um in units W/m2
RPAR reflected photosynthetically active radiation (wavelength range 400-700 nm) in units umol/(m2s)
PAR photosynthetically active radiation (wavelength range 400-700 nm) in units umol/(m2s)
(i.e. 1 umol of photons = 6.02*10^17 photons); duplicate instrument to PAR2
canIR out-going far-infrared radiation emitted by canopy and ground surface in units W/m2
PAR2 photosynthetically active radiation (wavelength range 400-700 nm) in units umol/(m2s)
(i.e. 1 umol of photons = 6.02*10^17 photons); duplicate instrument to PAR
LWin incoming far-infrared radiation in units W/m2
LWout out-going far-infrared radiation in units W/m2
PRI Photochemical reflectance index (dimensionless)
NDVI Normalised difference vegetation index (dimensionless)
bNDVI "broadband NDVI" calculated from incident and reflected global radiation and PAR (dimensionless)
maaPAR PAR at 0.6 m height above the forest floor (east of REA cottage) in units umol/(m2s)
maaNet Net radiation at 0.6 m height above the forest floor (east of REA cottage) in units umol/(m2s)
canPAR1 PAR at 0.6 m height above the forest floor (west of REA cottage) in units umol/(m2s)
canPAR2 PAR at 0.6 m height above the forest floor (halfway between main cottage and REA cottage) in units umol/(m2s)
canPAR3 PAR at 0.6 m height above the forest floor (north of tree tower) in units umol/(m2s)
Precip amount of rainfall in units mm
SWS rain indicator signal in units mV
UV-A, UV-B, diffPAR, diffGlob, Glob, PAR, PAR2, Precip and SWS are measured above the forest at 18 m height.
Net, RGlob, RPAR, canIR is measured at 70 m height in the Mast.
Glob, Net and PAR are measured as the total (global) radiation, i.e. sum of direct and
diffuse radiation. Starting 1.1.2006 Glob signal is corrected due to sun elevation angle (i.e. cosine correction).
Between 1.1.1996 - 31.12.2005 Glob signal is not corrected due to sun elevation angle.
Net and PAR signals are not corrected due to sun elevation angle.
UV-A and UV-B are measured as the total (global) radiation, i.e. sum of direct and
diffuse radiation. A correction to the signals due to sun elevation angle (i.e. cosine correction)
is performed.
diffGlob is measured using a shadow ring to prevent direct light from reaching the sensor.
Precipitation reading valid only for rainfall. During sleet and snow fall the reading is suspicious, i.e. for
temperatures < 0 or even near +0 are not reliable.
SWS signal > ca. 915 mV means dry sensor surface. When water deposits on the surface the signal decreases
gradually going down below 400 mV with totally wet surface. The sensor is slightly heated to speed up
the drying of the surface after rain.
Sensors
UV-A SL 501A UVA pyranometer (Solar Light, Philadelphia, PA, USA)
UV-B SL 501A UVB pyranometer (Solar Light, Philadelphia, PA, USA)
Glob Reemann TP 3 pyranometer (Astrodata, Tõravere, Tartumaa, Estonia) until 15th June 2008 and
Middleton Solar SK08 First Class Pyranometer (Middleton Solar, Yarraville, Australia) since 15th June 2008
Net Reemann MB 1 pyranometer (Astrodata, Tõravere, Tartumaa, Estonia)
PAR LI-190SZ quantum sensor (Li-Cor, Lincoln, NE, USA)
RPAR LI-190SZ quantum sensor (Li-Cor, Lincoln, NE, USA)
Rglob Reemann TP 3 pyranometer (Astrodata, Tõravere, Tartumaa, Estonia)
diffGlob Reemann TP 3 pyranometer (Astrodata, Tõravere, Tartumaa, Estonia) until 18 Mar 2010
diffPAR Sunshine sensor BF3 (Delta-T Devices Ltd., Cambridge, UK) starting 7th Dec 2009
canIR not measured
PAR2 Sunshine sensor BF3 (Delta-T Devices Ltd., Cambridge, UK) starting 7th Dec 2009
LWin/LWout CNR1 net radiometer (Kipp & Zonen, Delft, the Netherlands) starting Nov 2009
PRI 2x SKR 1800 (in and out, Skye Instruments Ltd, Powys, UK) starting Nov 2009
NDVI 2x SKR 1800 (in and out, Skye Instruments Ltd, Powys, UK) starting Nov 2009
maaPAR 4x LI-190SZ quantum sensor (Li-Cor, Lincoln, NE, USA)
canPAR1 5x SQ-100 quantum sensor (Apogee Instruments, Logan, UT, USA) starting 19th Nov 2010
canPAR2 5x SQ-100 quantum sensor (Apogee Instruments, Logan, UT, USA) starting 24th June 2010
canPAR3 5x SQ-100 quantum sensor (Apogee Instruments, Logan, UT, USA) starting 24th June 2010
Precipitation meter is ARG-100 tipping bucket counter (Vector Instruments, Rhyl, Clwyd, UK)
SWS sensor is DRD 11-A raindetector (Vaisala, Vantaa, Finland)
The radiation and SWS data are given as 1-min averages. Precipitation data is given as accumulated rainfall during 1 minute.
PWS data
time YYYYMMDDHHMMSS (beginning of averaging period, UTC+2)
Visibility visibility in units km
Visibilitymin minimum visibility in units km
Visibilitymax maximum visibility in units km
Precipint precipitation intensity in units mm/h
Precipintmin minimum precipitation intensity in units mm/h
Precipintmax maximum precipitation intensity in units mm/h
Precipacc Precipitation in unit mm
Snowfallacc snowfall in unit mm
Wthcode WMO synop code for most frequent weather type (see code table below)
Wthcodemin WMO synop code for "best" weather type (see code table below)
Wthcodemax WMO synop code for "worst" weather type (see code table below)
Precipitation is measured above the forest at 18 m height.
Precipitation meter is FD12P Weather sensor (Vaisala Oyj, Helsinki, Finland).
FD12P measures all precipitation as liquid water, and converts the portion of snow to snowfall.
Measurements are made at 1 min interval.
Maximum visibility reading is 50 km.
The visibility and precipitation intensity data are given as medians over averaging period.
The precipitation and snowfall are given as accumulated values during averaging period.
WMO SYNOP Codes (Table 4680, WaWa )
00 Clear
04 Haze or smoke, or dust in suspension in the air, visibility equal to, or greater than 1 km
05 Haze or smoke, or dust in suspension in the air, visibilty less than 1 km
10 Mist
Code figures 20 to 25 are used, if precipitation or fog was observed during the preceding hour but not at the time of observation
20 Fog
21 PRECIPITATION
22 Drizzle (not freezing) or snow grains
23 Rain ( not freezing)
24 Snow
25 Freezing rain or freezing drizzle
The following code figures are used if precipitation or fog is observed at the time of observation
30 FOG
31 Fog or ice fog, in patches
32 Fog or ice fog, has become thinner during the past hour
33 Fog or ice fog, no appreciable change durring the past hour
34 Fog or ice fog, has begun or become thicker during the past hour
40 PRECIPITATION
41 Precipitation, slight or moderate
42 Precipitation, heavy
50 DRIZZLE
51 Drizzle, not freezing, slight
52 Drizzle, not freezing, moderate
53 Drizzle, not freezing, heavy
54 Drizzle, freezing, light
55 Drizzle, freezing, moderate
56 Drizzle, freezing, heavy
60 RAIN
61 Rain, light
62 Rain, moderate
63 Rain, heavy
64 Rain, freezing, light
65 Rain, freezing, moderate
66 Rain, freezing, heavy
67 Rain (or drizzle) and snow, light
68 Rain (or drizzle) ans snow, moderate or heavy
70 SNOW
71 Snow, light
72 Snow, moderate
73 Snow, heavy
74 Ice pellets, light
75 Ice pellets, moderate
76 Ice pellets, heavy
77 Snow grains (from WMO 4677)
78 Ice crystals (from WMO 4677)
80 SHOWERS OR INTERMITTENT PRECIPITATION
81 Rain showers, light
82 Rain showers, moderate
83 Rain showers, heavy
84 Rain showers, viloent ( > 32 mm/h)
85 Snow showers, light
86 Snow showers, moderate
87 Snow showers, heavy
89 Showers of hail, with or without rain or rain and snow mixed, not associated with thunder (from WMO 4677)
Eddy data (HYY_EDDY233)
1 Yr yy measurement year
2 Day day number number of day from year’s beginning
3 h hh starting hour of ½ an hour period
4 m m or mm starting minute of ½ an hour period
5 Sonic_H W·m^-2^ sensible heat flux neg. sign downwards
6 LE W·m^-2^ latent heat flux neg. sign downwards
7 E mmol·m^-2^ s^-1^ water vapour flux neg. sign downwards
8 F_c mmol·m^-2^ s^-1^ carbon dioxide flux neg. sign downwards
9 tau m2·s^-2^ momentum flux neg. sign downwards
10 u^* m·s-1^ friction velocity
11 MO_length m Monin-Obukhov length
12 std_u m·s^-1^ st. deviation of wind component u
13 std_v m·s^-1^ st. deviation of wind component v
14 std_w m·s^-1^ st. deviation of wind component w
15 std_t °C st. deviation of air temperature
16 std_c mmol·mol st. deviation of CO2 concentration
17 std_h mmol·mol^-1^ st. deviation of H2O concentration
18 av u m·s^-1^ average wind component u
19 av v m·s^-1^ average wind component v
20 av w m·s^-1^ average wind component w
21 av t °C average air temperature
22 av_c mmol·mol average CO2 concentration
23 av_h mmol·mol^-1^ average H2O concentration
24 av U m·s^-1^ average horiz. wind (u & v combined)
25 wind_dir ° average wind direction
26 Eta ° co-ordinate rotation angle
27 Theta ° co-ordinate rotation angle
28 Beta ° co-ordinate rotation angle
29 c_lag 1/20 s CO2 concentration lag time
30 h_lag 1/20 s H2O concentration lag time
31 err_packet number number of erraneous data packets
32 covar_T_L-w °C·m·s^-1^ no data
33 std_T_L °C st. deviation of LiCor temperature
34 av_T_L °C average LiCor temperature
35 T_L_lag 1/20 s no data
36 covar_P_L-w kPa·m·s^-1^ no data
37 std_p_L kPa st. deviation of LiCor sample pressure
38 av_p_L kPa average LiCor sample pressure
39 p_L_lag 1/20 s no data
40 F_CPC 109 m^-2^·s^-1^ particle flux neg.sign downwards
41 std_CPC 103 cm^-3^ st. deviation of particle concentration
42 av_CPC 103 cm^-3^ average particle concentration, CPC connected 01.08.2000
43 CPC_lag 1/20 s CPC concentration lag time
Soil data (in HYY_META)
tsoil_humus Soil temperature in humus in C
tsoil_A Soil temperature 2-5 cm below mineral soil surface in C
tsoil_B1 Soil temperature 9-14 cm below mineral soil surfaces in C
tsoil_B2 Soil temperature 22-29 cm below mineral soil surface in C
tsoil_C1 Soil temperature 42-58 cm belowmineral soil surface in C
wsoil_humus Water content in humus in m^3/m^3
wsoil_A Soil water content 2-6 cm below mineral soil surface in m^3/m^3
wsoil_B1 Soil water content 14-25 cm below mineral soil surface in m^3/m^3
wsoil_B2 Soil water content 26-31 cm below mineral soil surface in m^3/m^3
wsoil_C1 Soil water content 36-49 cm below mineral soil surface in m^3/m^3
Some others
CO2_storage_flux umol•m-2 s-1
H2OTd from dew point data ppth
SD Snow depth cm