Validation of general circulation model radiative fluxes using surface observations

Journal Article · Mon May 01 04:00:00 EDT 1995 · Journal of Climate

DOI:https://doi.org/10.1175/1520-0442(1995)008<1309:VOGCMR>2.0.CO;2· OSTI ID:95956

Wild, M; Oshmura, A; Gilgen, H ^[1]

---

1. Swiss Federal Institute of Technology, Zurich (Switzerland); and others

The surface radiative fluxes of the ECHAM3 General Circulation Model (GCM) with T21, T42, and T106 resolutions have been validated using observations from the Global Energy Balance Archive (GEBA, World Climate Program-Water Project A7). GEBA contains the most comprehensive dataset now available for worldwide instrumentally measured surface energy fluxes. The GCM incoming shortwave radiation at the surface has been compared with more than 700 long-term monitoring stations. The ECHAM3 models show a clear tendency to overestimate the global annual-mean incoming shortwave radiation at the surface due to an underestimation of atmospheric absorption. The model-calculated global-mean surface shortwave absorption around 165 W M{sup -2} is estimated to be too high by 10-15 W m{sup -2}. A similar or higher overestimate is present in several other GCMs. Deficiencies in the clear-sky absorption of the ECHAM3 radiation scheme are proposed as a contributor to the flux discrepancies. A stand-alone validation of the radiation scheme under clear-sky conditions revealed overestimates of up to 50 W m{sup -2} for daily maximum values of incoming shortwave fluxes. Further, the lack of shortwave absorption by the model clouds is suggested to contribute to the overestimated surface shortwave radiation. There are indications that the incoming longwave radiation at the surface is underestimated in ECHAM3 and other GCMs. This largely offsets the overestimated shortwave flux in the global mean, so that the 102 W m{sup -2} calculated in ECHAM3 for the surface net radiation is considered to be a realistic value. A common feature of several GCMs is, therefore, a superficially correct simulation of global mean net radiation, as the overestimate in the shortwave balance is compensated by an underestimate in the longwave balance. 41 refs., 14 figs., 5 tabs.

• OSTI ID: 95956
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 5 Vol. 8; ISSN JLCLEL; ISSN 0894-8755
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ATMOSPHERIC CIRCULATION
CLOUDS
ENERGY BALANCE
GENERAL CIRCULATION MODELS
HEAT FLUX
SURFACE ENERGY
VALIDATION