Sentence:  The constant <WSD>temperature</WSD> contours are much smoother than those observed at 4.3 mm by Coates ( 1959 a ) , and apparently the emission at 8 mm is not nearly so sensitive to differences in surface features . 
Meaning of the word marked with <WSD> tags:  the degree of hotness or coldness of a body or environment (corresponding to its molecular activity)