The chemical evolution of the Sacramento urban plume (California)
- 出版日期：2002.
- 页数：206 p. :
- 第一责任说明：Michael Benjamin Dillon.
- 分类号：a274
MARC全文
02h0025390 20110919144221.0 cr un||||||||| 110919s2002 xx ||||f|||d||||||||eng | AAI3082161 CNY371.35 NGL NGL NGL a274 Dillon, Michael Benjamin. The chemical evolution of the Sacramento urban plume (California) [electronic resource] / Michael Benjamin Dillon. 2002. 206 p. : digital, PDF file. Source: Dissertation Abstracts International, Volume: 64-02, Section: B, page: 0589. ; Chair: Ronald C. Cohen. Thesis (Ph.D.) -- University of California, Berkeley, 2002. Observations of hydrocarbons, nitrogen oxides, and ozone in the Sacramento, California region are analyzed using a Lagrangian plume model. The analysis indicates that the Sacramento urban plume is typically diluted to 29% of the urban core concentration and oxidized by an average of 1.4 × 10 7 molecules cm-3 of OH radicals over a five hour period. The model is capable of accurately reproducing hydrocarbon, NO x, and NOy observations at the University of California - Blodgett Forest Research Station (UC-BFRS); however, it overestimates ozone mixing ratios within the urban plume by 25 ppb or 35%. This discrepancy demonstrates that our Lagrangian model constrains the average atmospheric ozone production rate to within a factor of two. This degree of precision is sufficient to distinguish between different methods of calculating ozone production rates. The Lagrangian model represents a tool to assess if current photochemical mechanisms accurately capture all relevant tropospheric ozone photochemistry. For the model to accurately describe ozone, we require a combination of minimal reactive hydrocarbon and formaldehyde sources downwind of the Sacramento urban core, which reduce the modeled ozone production rate by 55%, and more vigorous mixing in the first half of the plume than in the second half.;Our Lagrangian analysis of NOx and NOy in the Sacramento urban plume suggests that much could be learned from a more complete analysis of NOy partitioning. Here we also evaluate a new technique for observing speciated NOy, Thermal Dissociation - Laser Induced Fluorescence (TD-LIF), by comparison to a metalcatalysis/ozone chemiluminescence NO y detector (CL). We compare 960 hours of simultaneous 1 minute observations at the UC-BFRS taken by the two instruments. The instruments agree to within 10%. This agreement varies with season: the CL observations were greater than the TD-LIF observations by 6% both in the fall and winter months and the TD-LIF observations were greater than the CL observations by 20% and 10% in the spring and summer months, respectively. The conversion of NH3 to NO 2 in the TD-LIF HNO3 channel is consistent with the magnitude and seasonal cycle of the instrumental differences based on internal TD-LIF diagnostics, prior observations of HNO3 and NH3 in the Sierra Nevada, a theoretical NH3 decomposition mechanism, and preliminary laboratory experiments. During the summer mornings, the CL observations were greater than the TD-LIF observations by 500 ppt (30%) when corrected for the NH3 interference. This additional signal in the CL instrument may be HONO given the unique conversion method of the TD-LIF instrument, the time in which the signal is observed, and prior observations of HONO in the Sierra Nevada mountains. Air ; Atmospheric chemistry. Pollution Sacramento, Calif. Electronic books. aeBook. aCN bNGL http://proquest.calis.edu.cn/umi/detail_usmark.jsp?searchword=pub_number%3DAAI3082161&singlesearch=no&channelid=%CF%B8%C0%C0&record=1 NGL Bs922 rCNY371.35 ; h1 bs1107