Modeling the effect of ozone loss on photobleaching of chromophoric dissolved organic matter in the St. Lawrence estuary

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	Modeling the effect of ozone loss on photobleaching of chromophoric dissolved organic matter in the St. Lawrence estuary
	Robert F. Whitehead ; Stephen J. de Mora
发表期刊	GLOBAL BIOGEOCHEMICAL CYCLES
ISSN	0886-6236
	2004
卷号	18 页码:11
通讯作者	Robert F. Whitehead
英文摘要	Temporal trends in total ozone for the St. Lawrence estuary were estimated from ground-based measurements at the NOAA/CMDL station in Caribou, Maine. Linear regression analysis showed that from 1979 to 1999 total ozone has decreased by about 3.3% per decade on an annual basis and ≤6.2% per decade on a monthly basis relative to unperturbed (pre-CFC) levels. The influence of increased ultraviolet-B (280–320 nm) radiation associated with ozone depletion on water column photochemical processes was evaluated by modeling the photobleaching of chromophoric dissolved organic material (CDOM). Linear regression analysis showed small (<0.5% per decade), but statistically significant upward trends in maximum noontime photobleaching rates. Most notably, positive trends in relative rates for May, June, and July, when maximum absolute rates are expected, were predicted. A global model based on TOMS ozone data revealed increases in photobleaching of ≤3% per decade at high latitudes in the Southern Hemisphere. Radiation amplification factors for increases in photochemically weighted UV (280–400 nm) in response to ozone depletion were estimated at 0.1 and 0.08 for photobleaching of CDOM absorbance at 300 and 350 nm, respectively. Application of the laboratory-based model to conditions that more closely resembled those in situ were variable with both overestimation and underestimation of measured rates. The differences between modeled rates and observed rates under quasi-natural conditions were as large or larger than the predicted increases due to ozone depletion. These comparisons suggest that biological activity and mixing play an important, but as yet ill-defined, role in modifying photochemical processes.
语种	英语
文献类型	期刊论文
条目标识符	http://ir.yic.ac.cn/handle/133337/3099
专题	科研共享资源
推荐引用方式 GB/T 7714	Robert F. Whitehead,Stephen J. de Mora. Modeling the effect of ozone loss on photobleaching of chromophoric dissolved organic matter in the St. Lawrence estuary[J]. GLOBAL BIOGEOCHEMICAL CYCLES,2004,18:11.
APA	Robert F. Whitehead,&Stephen J. de Mora.(2004).Modeling the effect of ozone loss on photobleaching of chromophoric dissolved organic matter in the St. Lawrence estuary.GLOBAL BIOGEOCHEMICAL CYCLES,18,11.
MLA	Robert F. Whitehead,et al."Modeling the effect of ozone loss on photobleaching of chromophoric dissolved organic matter in the St. Lawrence estuary".GLOBAL BIOGEOCHEMICAL CYCLES 18(2004):11.

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