Stratospheric H2O

The h2o-module for stratospheric water vapor

IMPORTANT: set the switch at the beginning of h2o.nml (namelist) to the proper value!

  • The option 1 is useful WITHOUT a CHEMISTRY module but for example a psc-module (initialization + climatological chemical tendency, feedback to humidity). –RECOMMENDED–
  • If a chemistry module is present, e.g. mecca, which calculates a chemical tendency for [H2O], the switch should be set to 0 (feedback to humidity). –RECOMMENDED– CCM as in evaluation
  • The option 2 might be used for stratospheric studies without any chemistry or PSC-module for inclusion of the climatological source from methane oxidation. Good also for tests which exclude feedbacks of chemistry on dynamics. Caution: in the troposphere the initialization of ECHAM (QM) is used, any other initialization of H2O is overwritten.

Only for testpurposes or comparison with the naked ECHAM:

  • Option -1: initialization of the H2O tracer from satellite data only,
  • Option -2: Use the unrealistic ECHAM-values in the stratosphere (typically off by a factor of 4 or more, causes errors in radiative cooling in the upper stratosphere by 1-2K/day)

Advection, condensation and evaporation always transfered to the H2O-tracer via the humidity tendency.