Ilman lämpötilan mittaamisesta erilaisia säteilysuojuksia käyttäen

Authors

• Yrjö Pessi Hallakoeasema, Pelso

DOI: https://doi.org/10.23986/afsci.71359

Abstract

Measurements of the minimum air temperature above a grass field have been made at the Frost Research Station during frosty nights using different radiation shields. In comparison with thermometers where the Budig shield was used above the liquid reservoir, those with cylindrical radiation shields gave, on average, values 0.5°C. lower, those without a shield values 1.1° lower, and those with the Budig shield below the liquid reservoir values 1.9° lower (Tab. 1). The error due to radiation when the Budig shield was used was —0.4° and —0.2° with wind velocities of 0.3 and 1.5 m./sec. and with radiation balance —0.11 g.cal./cm2 X minute. The most suitable method in practice was considered to be the cylindrical radiation shield, though nearly correct minimum temperatures are obtained using the Budig shield above the liquid reservoir.