Место издания:Riso National Laboratory, Roskilde, Denmark
Первая страница:87
Последняя страница:90
Аннотация:The question of accuracy of the determination of the mixing height as the input parameter for short-range dispersion models is considered. It is demonstrated that applicability of those or other methods of the mixing height determination depends on influence of its errors on the results of modeling. Criteria of allowable errors, which depend on both the class of models and the values of the mixing height, are suggested.
The results of comparisons of the mixing height values taken from sodar data and from profiles of the potential temperature are presented. The sodar was operated in the residential area of Moscow; the site of launching the low-level radiosondes and the standard radiosondes was situated in the suburbs, 13 km from sodar.
The comparisons have shown that under the conditions of developed convection the mixing height values derived from sodar and radiosondes are agreed between themselves within the formulated criteria. However, such conditions in Moscow happen only in 3 % of the total annual time. Under other conditions the standard radiosondes data either give no way to determination of the mixing height over city, or give unreal estimations of it.
The results of estimations of the mixing heights over Moscow by long-term sodar measurements are presented. The satisfactory accuracy of these estimations is confirmed by results of their comparison with data of synchronous measurements of the local gas impurity concentrations.
From obtained results the conclusion is made that sodar is quite acceptable and the most accessible tool for operational and climatological determination of the mixing heights to estimate dispersion potential of the lower atmosphere over large cities.