Adriatic-Ionian air temperature and precipitation patterns derived from self-organizing maps: relation to hemispheric indices

Abstract

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 78:149-163 (2019) - DOI: https://doi.org/10.3354/cr01565 Adriatic-Ionian air temperature and precipitation patterns derived from self-organizing maps: relation to hemispheric indices Frano Matić1,*, Hrvoje Kalinić2, Ivica Vilibić1, Branka Grbec1, Karla Morožin3 1Institute of Oceanography and Fisheries, 21000 Split, Croatia 2Faculty of Science, University of Split, 21000 Split, Croatia 3Department of Marine Studies, University of Split, 21000 Split, Croatia *Corresponding author: fmatic@izor.hr ABSTRACT: Normalized anomalies in air temperature and precipitation patterns derived from monthly data series collected at 28 in situ meteorological stations in the Adriatic-Ionian region between 1961 and 2015 were mapped by using the self-organizing map (SOM) method—an unsupervised neural network method—and connected with hemispheric indices in the atmosphere. Four indices were used: North Atlantic Oscillation (NAO), East Atlantic (EA), East Atlantic/West Russia (EAWR) and Scandinavian (SCA). Two experiments were conducted: the first combined normalized temperature anomalies with the indices, and the second combined normalized precipitation anomalies with the indices. Precipitation data better fit the SOM model than temperature data, while the SOM model has the best performance at a 3 × 3 matrix size. Region-wide negative precipitation anomalies are related to a combination of positive NAO and EAWR, and negative SCA indices, and vice versa. Positive air temperature anomalies are related to the positive EA index and vice versa. The mapped relations between the NAO index and precipitation anomalies indicate a nonlinear connection, because positive index values resemble 2 different precipitation patterns. The SOM-based nonlinear clustering might be useful in determining and forecasting precipitation and air temperature patterns from hemispheric indices. KEY WORDS: Self-organizing maps · Air temperature · Precipitation · Hemispheric indices · Central Mediterranean Full text in pdf format PreviousNextCite this article as: Matić F, Kalinić H, Vilibić I, Grbec B, Morožin K (2019) Adriatic-Ionian air temperature and precipitation patterns derived from self-organizing maps: relation to hemispheric indices. Clim Res 78:149-163. https://doi.org/10.3354/cr01565 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 78, No. 2. Online publication date: August 08, 2019 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2019 Inter-Research.