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Cluster‐Based Evaluation of Model Compensating Errors: A Case Study of Cloud Radiative Effect in the Southern Ocean
Author(s) -
Schuddeboom Alex,
Varma Vidya,
McDonald Adrian J.,
Morgenstern Olaf,
Harvey Mike,
Parsons Simon,
Field Paul,
Furtado Kalli
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl081686
Subject(s) - radiative transfer , cloud computing , shortwave , cluster (spacecraft) , latitude , satellite , ranking (information retrieval) , environmental science , climate model , meteorology , climatology , remote sensing , computer science , geography , physics , geology , geodesy , climate change , machine learning , quantum mechanics , astronomy , programming language , operating system , oceanography
Model evaluation is difficult and generally relies on analysis that can mask compensating errors. This paper defines new metrics, using clusters generated from a machine learning algorithm, to estimate mean and compensating errors in different model runs. As a test case, we investigate the Southern Ocean shortwave radiative bias using clusters derived by applying self‐organizing maps to satellite data. In particular, the effects of changing cloud phase parameterizations in the MetOffice Unified Model are examined. Differences in cluster properties show that the regional radiative biases are substantially different than the global bias, with two distinct regions identified within the Southern Ocean, each with a different signed bias. Changing cloud phase parameterizations can reduce errors at higher latitudes but increase errors at lower latitudes of the Southern Ocean. Ranking the parameterizations often shows a contrast in mean and compensating errors, notably in all cases large compensating errors remain.