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Measurements of Dry Deposition of No 2 to A Dutch Heathland Using the Eddy‐Correlation Technique
Author(s) -
Coe H.,
Gallagher M. W.
Publication year - 1992
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.49711850608
Subject(s) - eddy covariance , canopy , atmospheric sciences , environmental science , anemometer , flux (metallurgy) , deposition (geology) , analytical chemistry (journal) , chemistry , zoology , soil science , meteorology , wind speed , geology , botany , physics , ecology , environmental chemistry , biology , paleontology , organic chemistry , ecosystem , sediment
Nitrogen dioxide (NO 2 ) fluxes were determined over a dry heather moor by the eddy‐correlation technique using a sonic anemometer and two Scintrex LMA‐3 chemiluminescent analysers. Using power spectral analysis virtually all the fluctuations in NO 2 concentration were of frequencies less than 1 Hz at the measuring height of 5.32m. Even with the non‐ideal response of the LMA‐3 little information about NO 2 concentration was lost. Co‐spectral analysis showed there was no loss of flux at high frequencies arising from the slow response of the LMA‐3. NO 2 was deposited at a constant rate of 0.02 μg m‐ 2 ‐ 1 for nearly all of the measuring period. the deposition velocity maintained a mean value of 1 mm s‐ 1 throughout with minimum values nearing zero and maximum values of 3.5 mms‐ 1 . There was no diurnal variation in canopy resistances to NO 2 . Mean values were 548 s m‐ 1 and 400 sm‐ 1 with and without the inclusion of several brief periods when the resistance increased markedly. Except for a brief period on 1 May the deposition was to the leaf cuticle as temperature and water stress caused the stomata to be closed. During the afternoon of 1 May there was some stomatal activity when the canopy resistance to water vapour fell and NO 2 flux increased. Finally a simulation of the cumulative sampling method was performed on the data set as described in Businger and Oncley (1990). They calculated a constant of proportionality, b , and showed it to have a value of 0.6 when considering heat and water‐vapour fluxes. A value of b was calculated for NO 2 flux using the data set presented here and was found to be 0.58.