ELDONET – EUROPEAN LIGHT DOSIMETER NETWORK - Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models - page 91

ELDONET - EUROPEAN LIGHT DOSIMETER NETWORK

DONAT-P. HÄDER AND MICHAEL LEBERT
Friedrich-Alexander-Universität,

und
Pharmazeutische Biologie, Staudtstr. 5, D-91058 Erlangen, Germany

Institut für Botanik

1. Abstract

A network of three channel dosimeters has been installed in Europe and other continents
to continuously and automatically monitor solar radiation in the UV-B (280 - 315 nm),
UV-A (315 - 400 nm) and PAR (photosynthetic active radiation, 400 - 700 nm)
wavelength ranges to follow long-term and short-term changes in the light climate. The
instruments are housed in rugged cases to withstand extreme environments from the
polar circle to the tropics. The entrance optic is based on an integrating sphere and the
wavelength selection is done by appropriate filter and photodiode combinations.
Software packages have been developed to poll the data, display them graphically and
store them. Quality control is warranted by careful and frequent calibration of the
instruments as well as national and international intercalibrations. The data are sent to a
central server in Pisa from where they can be downloaded on the Internet free of charge.
The network has been in operation for the last five years and has constantly been
growing in numbers. The data are being used to extract important information on
changing light climate conditions and the development of stratospheric ozone.

2. Background

All forms of the biota on our planet are affected by solar radiation. Scientists
investigating these effects need precise instrumentation to measure the irradiation.
Starting from sporadic measurements, systematic monitoring of solar radiation has been
established to satisfy these needs. Distinct wavelength bands induce different responses,
so that it became important to measure spectrally resolved data. Following the discovery
of stratospheric ozone depletion caused by anthropogenic pollution, scientists became
concerned about the effects of the resulting increasing UV-B radiation (280 - 315 nm,
C.I.E. definition) on life 1 . One of the first study areas was an increase in UV-induced
human skin cancers 2-3 . Furthermore, UV-B is suspected to induce cataracts, impair the
human immune system and to be responsible for other health effects in humans and
animals 4-6 .
Other concerns deal with both wild and crop plants where UV-B causes adverse
effects, including decreased productivity and reduced food quality 7-10 . Solar UV
radiation inhibits photosynthesis 11-12 , stomatal movement 13-14 , growth and development
in about 50 % of all plants investigated so far 15-18 .