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Notes on the measurement and estimation of atmospheric radiation
Author(s) -
Robinson G. D.
Publication year - 1947
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49707331510
Subject(s) - emissivity , water vapor , radiation , environmental science , radiometer , calibration , atmosphere (unit) , atmospheric sciences , meteorology , earth's energy budget , observatory , remote sensing , mathematics , physics , optics , geology , statistics , astrophysics
A series of measurements of the infra red emission of the atmosphere has been made at Kew Observatory with Dines and Linke‐Fuessner radiometers. Precautions necessary during the calibration and use of these instruments are discussed, the results obtained with them compared, and the accuracy of the measurements assessed. Computation of the atmospheric emission by Elsasser's method is discussed, and compared with the experimental results. It is suggested that the divergence found is due to over‐estimation of the emissivity of water vapour in the presence of carbon dioxide by Elsasser, together with the presence of a variable additional component of radiation of from 0 to 8 per cent of the total. Some comments are made on the possible origin of this radiation. A modification of the method of F. A. Brooks is used to derive values of water vapour emissivity from the measurements, and by combining these with the laboratory values of Elsasser and Brooks an emissivity curve is obtained which differs from that now generally accepted. This is used to compute the water vapour radiation, and the construction of an empirical radiation chart is described. Finally it is shown that the outward radiation of the ground may be obtained from the reading of an ordinary thermometer, and that by combining this with an estimate of atmospheric emission based on routine upper air data, the net infra red radiation of the surface may be estimated with an accuracy better than 15 per cent.