Surface Radiation Measurements at Neumayer
Since March 1982 surface radiation balance measurements have been carried out at Georg-von-Neumayer. The radiation signals were taken at one minute intervals and stored as averages over 10 minutes. They include:
- global radiation (pyranometer CM11, Kipp+Zonen),
- reflected solar radiation (pyranometer CM11, Kipp+Zonen),
- downward long-wave radiation (pyrradiometer Lange),
- upward long-wave radiation (pyrradiometer Lange),
- sunshine duration (Solar 111, Haenni).
In March 1992 the radiation measurements at Neumayer were extended in order to fulfil the standards of the Baseline Surface Radiation Network (BSRN). The pyrradiometers were replaced by pyrgeometers (PIR, Eppley), the averaging period was first reduced to 5 minutes, in 1998 with measurements every 5 seconds to 1 minute and the following quantities are now additionally measured:
- diffuse sky radiation (pyranometer CM11, Kipp+Zonen),
- direct solar radiation (NIP, Eppley mounted on a sun tracker),
- OG1 (global>530nm, pyranometer CM11, Kipp+Zonen),
- RG8 (global>695nm, pyranometer CM11, Kipp+Zonen),
- UV (300-370nm, TUVR, Eppley).
The pyranometers and pyrgeometers are ventilated with slightly preheated air to minimize hoar frost problems and zero offsets during cloudless and windless conditions. The instruments are maintained continuously throughout the year. After one year of operation they get re-calibrated at the Word Radiation Center according the World Radiometric Reference (WRR).
Radiation balance 1982-1992
Annual variation of surface radiation balance 1993
Publications
The radiation measurements of Neumayer Station from 1982 - 1992 are published in the Report on Polar Research Volume 146 which is available from the
Alfred Wegener Institute
Foundation for Polar and Marine Research, Bremerhaven
Postfach 12 0161
D-27515 Bremerhaven.
Archiving and Retrieving Data
At AWI, the radiation measurements - averaged over 10 (5) minutes - are archived together with the data from the mast measurements, daily upper air soundings and routine synoptic surface observations in a relational database (SYBASE). Additionally some derived quantities (Iqbal 1983) such as the solar elevation, extraterrestrial solar insolation, astronomical sunshine duration are available.
In order to obtain daily averaged radiation data, each day was subdivided into eight 3-hourly intervals (0-3, 3-6, ..., 21-24 UTC). For each 3-hourly interval an average was derived irrespective of the number of measurements. This procedure was chosen in order to minimize problems resulting from missing values. If one or more 3-hourly averages were missing, no daily average was calculated.
The direct radiation is measured with respect to a plain perpendicular to the sun. All other radiation fluxes are measured with respect to a horizontal plain.
Pyranometer as well as pyheliometer are equipped with thermopiles which have a certain cross sensitivitiy to temperature effects not associated with radiation fluxes. A quantification of this cross sensitivitiy is possible with the data taken during night.
Measurements for the global and refleced short-wave radiation fluxes as well as for the incomming and outgoing long-wave components are available from March 13 1982. Since March 1992, the full dataset is available.The data in the database can be retrieved directly in two different forms:
- daily averages (up to one month at a time)
- full time resolution (day by day).