Opened 11 years ago

Last modified 10 years ago

## #74 new defect

# Validación de GCMs: Errores de Z crecen con la altura

Reported by: | SwenBrands | Owned by: | gutierjm |
---|---|---|---|

Priority: | major | Milestone: | |

Component: | Otro | Keywords: | GCM error |

Cc: | chus, lluis, MarkelGarcia, antonio |

### Description

Validando los GCMs de ENSEMBLES contra ERA-40, hemos comprobado que un error dado para Z en 850 hPa crece con la altura. Un revisor del artículo enviado a Climate Research nos da una explicación física de este fenómeno que será de interés para algunos:

"The authors ask me to explain why I understand that the deterioration of performance of geopotential height might be explained on the basis of hydrostatic equilibrium. Starting from the hypsometric equation

P=Ps*exp(-z/H)

we can write:

z=Rd/g*ln(Ps/P) * T

So, errors in T below any level P are being multiplied by the constant Rd/g*ln(Ps/P) before they get converted to errors in z. Thus, as P takes lower values (upper atmospheric levels), this constant grows and errors in Z are higher due to errors in T below that isobaric level (unless errors in temperature cancel in the vertical, something that seems difficult to happen in a systematic way). The value of the constant Rd/g*ln(Ps/P) is almost 11 at 700 hPa and almost 21 at 500 hPa (assuming Ps=1013.25 hPa). I hope this explains what I meant in my previous revision. This is consistent with the result given by the authors in line 290 of the current version of the manuscript."

**Note:**See TracTickets for help on using tickets.

hola quiero saber los resultados de examenes del dia 11 de julio

_{ mi nombre y apellido es moriconi horacio 25413386 }