Beitrag
Evaluation of the MiKlip decadal prediction system using satellite based cloud products
Spangehl, Thomas; Schröder, Marc; Stolzenberger, Sophie; Glowienka-Hense, Rita; Mazurkiewicz, Alex; Hense, Andreas
Meteorologische Zeitschrift Vol. 25 No. 6 (2016), p. 695 - 707
27 Literaturangaben
veröffentlicht: Dec 21, 2016
Online veröffentlicht: Apr 4, 2015
Manuskript akzeptiert: Nov 25, 2014
Manuskript-Revision erhalten: Nov 20, 2014
Manuskript-Revision angefordert: Jan 2, 2014
Manuskript erhalten: Mar 16, 2014
Open Access (Arbeit kann kostenlos heruntergeladen werden)
Abstract
The decadal hindcast simulations performed for the Mittelfristige Klimaprognosen (MiKlip) project are evaluated using satellite-retrieved cloud parameters from the CM SAF cLoud, Albedo and RAdiation dataset from AVHRR data (CLARA-A1) provided by the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) and from the International Satellite Cloud Climatology Project (ISCCP). The forecast quality of two sets of hindcasts, Baseline-1-LR and Baseline-0, which use differing initialisations, is assessed. Basic evaluation focuses on multi-year ensemble mean fields and cloud-type histograms utilizing satellite simulator output. Additionally, ensemble evaluation employing analysis of variance (ANOVA), analysis rank histograms (ARH) and a deterministic correlation score is performed. Satellite simulator output is available for a subset of the full hindcast ensembles only. Therefore, the raw model cloud cover is complementary used. The new Baseline-1-LR hindcasts are closer to satellite data with respect to the simulated tropical/subtropical mean cloud cover pattern than the reference hindcasts (Baseline-0) emphasizing improvements of the new MiKlip initialisation procedure. A slightly overestimated occurrence rate of optically thick cloud-types is analysed for different experiments including hindcasts and simulations using realistic sea surface boundaries according to the Atmospheric Model Intercomparison Project (AMIP). By contrast, the evaluation of cirrus and cirrostratus clouds is complicated by observational based uncertainties. Time series of the 3-year mean total cloud cover averaged over the tropical warm pool (TWP) region show some correlation with the CLARA-A1 cloud fractional cover. Moreover, ensemble evaluation of the Baseline-1-LR hindcasts reveals potential predictability of the 2–5 lead year averaged total cloud cover for a large part of this region when regarding the full observational period. However, the hindcasts show only moderate positive correlations with the CLARA-A1 satellite retrieval for the TWP region which are hardly statistical significant. Evidence for predictability of the 2–5 lead year averaged total cloud cover is found for parts of the equatorial to mid-latitudinal North Atlantic.
Schlagworte
decadal prediction • clouds • satellite simulator • MiKlip