排序方式: 共有4条查询结果,搜索用时 0 毫秒
1
1.
2.
Sherri A. Mason Jörg Trentmann Tanja Winterrath Robert J. Yokelson Theodore J. Christian Lisa J. Carlson Thomas R. Warner Louise C. Wolfe Meinrat O. Andreae 《Journal of Atmospheric Chemistry》2006,55(3):273-297
Results from two independently developed biomass-burning smoke plume models are compared. Model results were obtained for the temporal evolution of two nascent smoke plumes originating from significantly different fire environments (an Alaskan boreal forest and an African savanna). The two smoke plume models differed by 1%–10% for [O3], with similar differences for NO
x
and formaldehyde (relative percent differences). Smaller intermodel differences were observed for the African savanna smoke plume as compared to the plume from the Alaskan boreal fire. Mechanistic differences between the models are heightened for the Alaskan smoke plume due to the higher VOC emission ratios as compared to the African savanna fire. The largest deviations result from the differences in oxidative photochemical mechanisms, with a smaller contribution attributable to the calculation of photolysis frequencies. The differences between the two smoke plume models are significantly smaller than the uncertainties of available photokinetic data or field measurements. Model accuracy depends most significantly on having the fullest possible VOC data, a requirement that is constrained by currently available instrumentation. 相似文献
3.
Sinnhuber B.-M. Müller R. Langer J. Bovensmann H. Eyring V. Klein U. Trentmann J. Burrows J. P. Künzi K. F. 《Journal of Atmospheric Chemistry》1999,34(3):281-290
In this study measurements of mid-stratospheric Arctic ozone are compared with model simulations. The measurements obtained at Spitsbergen (79°N, 12°E) by ground based millimeter-wave radiometry exhibit large day to day variabilities as well as periods with low ozone. To interpret these measurements, calculations were made using the new photochemical box-trajectory model BRAPHO, with air parcel trajectories calculated from analyzed wind fields. Using a relatively simple approach, the model reproduces the observed ozone variability well, including inter-annual variations. The explanation for the observed ozone behavior is that at these altitudes ozone is determined by what we call dynamically controlled photochemistry. This means that the photochemical evolution of the ozone volume mixing ratio is mainly controlled by the atmospheric dynamics, in particular the solar zenith angle the air parcel has experienced. 相似文献
4.
Jörg Trentmann Heinrich Bovensmann Veronika Eyring Richard W. Müller John P. Burrows 《Journal of Atmospheric Chemistry》2003,44(3):225-240
The interpretation of atmospheric measurements and the forecasting of the atmospheric composition require a hierarchy of accurate chemical transport and global circulation models. Here, the results of studies using Bremens Atmospheric Photochemical Model (BRAPHO) are presented. The focus of this study is given to the calculation of the atmospheric photolysis frequencies It is shown that the spectral high resolved simulation of the O2 Schumann–Runge bands leads to differences in the order of 10% in the calculated O2 photolysis frequency when compared with parameterizations used in other atmospheric models. Detailed treatment of the NO absorption leads to even larger differences (in the order of 50%) compared to standard parameterizations. Refraction leads to a significant increase in the photolysis frequencies at large solar zenith angles and, under polar spring conditions, to a significant change in the nighttime mixing ratio of some trace gases, e.g., NO3. It appears that recent changes in some important rate constants significantly alter the simulated BrOx- and HOx-budgets in the mid-latitude stratosphere. 相似文献
1