Abstract
A computation of the evaporation in meso scale areas, Kyushu Island and Setouchi district, by means of atmosheric water vapor budget has been tried using radiosonde observations. The calculation scheme for this analysis is introduced at chapt. 2, and the discussion on errors in such numerical analysis is described at chapt. 6.
1) It is useful even over the meso-scale area to estimate the evaporation with the method of water-vapor budget analysis.
2) It is better to take a short air column (from earth's surface to 850mb) to eliminate the influence of precipitation R and the transfer of liquid or solid water.
3) The calculation method by means of Electronic computer on the assumption that each meteorological quantity varies linearly between two adjacent stations is also available.
4) Evaporation has large values in the field of water vapor divergence and small values, in the field of water vapor convergence and when the storage of water vapor within the atmospheric column, ∫(∂q/∂t) (dp/g) shows high negative values.
5) Seasonal variation of the calculated E from both the areas follows closely the Thornthwaite's Potential Evaporation (PE) during January to August in (except Aprill), and each of Es in this duration, 653mm (Kyushu area), 539mm (Setouchi area) is quite close to PE's 607mm.
6) Evaporation seems to have relatively high values in drought seasons.
7) Evaporations caluclated with the data of two soundings at 09 and 21 JST give different values and those at 21 JST have always larger values than the values at 09 JST.
