The KNMI has provided video recording of the sky (A.), short- & NET long wave radiation (B.) and IR-radiation measurements (C.) for the duration of CLARE'98. The following data is available from this site:
During the campaign, a cloud video tape is made with a time lapse recorder. Six MPEG video movies were made from this tape for the chosen priority legs. Each 1.5 minute MPEG-movie shows 4 hours of time lapsed video recording; approximately 2 hours before and 2 hours after aircrafts passed overhead. The view reaches from the western horizon to near zenith. (Opening angle lens: Vert.; 88 degrees, Hor.; 107 degrees)
Both SW and LW were recorded for the duration of the campaign.
SW radiation was measured with two Kipp CM-11 pyranometers; one
up- and one downward looking. First a graphical interpretation
of the data is shown, followed by the hyperlink to the data.
The NET LW radiation was calculated from the LW radiation measurements
of a Schulze dual-dome radiometer and the SW observations. Data
was recorded with a Campbell 21X datalogger. 10 Minute averages
are available for the period 6 - 26 october, that is julian day
279 - 299.
SW-LW Radiation files & description
The radiometers (Heimann KT15.85) were equipped with a precipitation detector which controlled a mechanical cover to protect the Heimann against precipitation. (Instruments do not operate during rain, then Tsky = Tcover)
One IR-radiometer was fitted in the 3 Ghz radar dish to record the sky or cloud base temperature of the volume scanned by the dish and aircrafts. Flights were recorded when authorised RAL personal was available to perform a memory card switch. Data available from 7 ,13, 14, 16 & 22 oct.
Specifications dish IR-radiometer:
| Spectral range: | 9.6 to 11.5 micrometer |
| Temp.range : | -50 to +50 C |
| Sampling rate : | 1.0 sec. |
| Storing rate : | every 2 sec. (Average of 2 samples) |
| Parameters : | Tsky, Thouse, Precipitation, Tmax, Tmin, # observations within 5C of Tmax or Tmin |
The other IR-radiometer was installed on the roof of the main building of the Chilbolton Observatory to observe the overhead sky temperature. Due to a unknown reason, there was no data recorded after a memory card switch halfway the campaign. So, this data is only available from 6 to 15 oct.
Specifications roof IR-radiometer:
Identical as for dish-radiometer except:
| Sampling rate | 1.2 sec. |
| Storing rate : | every 10 min. (Average of 500 samples) |
IR Radiation files & description
In the following graph an example of a comparison between sky
temperature and LW radiation is shown;
Last update 4/3/1999
Questions about the data should be addressed to Andre v. Lammeren
or Eric Meijer who is making
fine adjustments to the radar in next picture.
