Influence of wind speed averaging on estimates of dimethylsulfide emission fluxes
Influence of wind speed averaging on estimates of dimethylsulfide emission fluxes
复制标题
风速平均对二甲硫醚排放通量估算的影响
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
S. Ghan
中科院分区：
文献类型：
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作者：
E. Chapman;W. Shaw;R. Easter;X. Bian;S. Ghan
[1]定量评价了不同风速平均周期对计算的二甲基硫化物（DMS）排放通量的影响。一个全球气候模式和一个排放通量模块在独立模式下运行了整整一年。将气候模式产生的20分钟瞬时地面风速及相关变量进行存档，并计算相应的1小时、6小时、日和月平均值。这些不同的时间平均的、模式衍生的量被用作发射通量模块的输入，DMS排放是使用大气模式中常用的传质速度的两种表达式来计算的[Liss和Merlivat, 1986；Nightingale et al., 2000]。结果表明，风速平均时段的选择会影响计算得到的DMS发射通量的大小。全球网格内的许多单个海洋单元显示，当使用20分钟瞬时模式时间步长风速而不是每月平均风速计算排放量时，DMS排放通量高出10-60%，并且在某些位置差异超过200%。这些细胞中有许多位于南半球，那里人为硫排放较低，海洋DMS排放的变化可能显著影响计算出的气溶胶浓度和气溶胶辐射强迫。
[1] The effect of various wind speed averaging periods on calculated dimethylsulfide (DMS) emission fluxes is quantitatively assessed. A global climate model and an emission flux module were run in stand-alone mode for a full year. Twenty-minute instantaneous surface wind speeds and related variables generated by the climate model were archived, and corresponding 1-hour, 6-hour, daily, and monthly averaged quantities were calculated. These various time-averaged, model-derived quantities were used as inputs in the emission flux module, and DMS emissions were calculated using two expressions for the mass transfer velocity commonly used in atmospheric models [Liss and Merlivat, 1986; Nightingale et al., 2000]. Results indicate that the time period selected for averaging wind speeds can affect the magnitude of calculated DMS emission fluxes. A number of individual marine cells within the global grid show DMS emissions fluxes that are 10–60% higher when emissions are calculated using 20-min instantaneous model time step winds rather than monthly averaged wind speeds, and at some locations the differences exceed 200%. Many of these cells are located in the Southern Hemisphere where anthropogenic sulfur emissions are low and changes in oceanic DMS emissions may significantly affect calculated aerosol concentrations and aerosol radiative forcing.