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The impact of a physically based microphysical scheme on the climate simulation of the meteorological office unified model
Author(s) -
Wilson Damian
Publication year - 2000
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712656505
Subject(s) - precipitation , environmental science , meteorology , convection , atmospheric sciences , climatology , general circulation model , scheme (mathematics) , climate model , ice crystals , climate change , mathematics , geology , geography , mathematical analysis , oceanography
The predictions of two, large‐scale precipitation schemes for a general‐circulation model are compared within a development version of the Meteorological Office's climate model. One scheme contains a prognostic ice content and a representation of mixed‐phase microphysical processes, whereas the second scheme is a diagnostic scheme where condensate is partitioned into liquid and ice as a function of temperature. Results show that, although the overall near‐surface conditions are similar, significant differences occur in the structure of clouds predicted by the two schemes. The total precipitation rate is similar, but the microphysical scheme has less convective activity than the temperature‐partition scheme, because of the different subgrid nature of the schemes. Layer‐cloud amounts are changed due to both changes in condensate and changes in its diagnosis. More ice is predicted by the microphysical scheme, mainly as a result of reduced fall speeds of ice particles. This shows the need for global measurement methods of ice‐water content to be developed.