edu.ucar.opensky::articles:42250 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T18:03:52.834883 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.net/ark:/85065/d7z03dfr A simple subtropical high‐pressure system index over the South Atlantic 2024-11-01T00:00:00Z publication https://n2t.net/ark:/85065/d7z03dfr https://doi.org/10.1002/asl.1266 Quagraine, Kwesi A. author Hewitson, B. author Nkrumah, F. author Quagraine, K. T. author Egbebiyi, T. S. author UCAR/NCAR - Library publisher This research introduces a novel index for the South Atlantic High Pressure (SAHP) system to enhance understanding of regional climate variability and change. Subtropical highs significantly influence regional climates, yet comprehensive indices to measure their behaviours are lacking. Utilizing ERA5 reanalysis data from 1940 to 2023, the proposed index estimates a weighted centroid of the area surrounding the maximum sea level pressure within a 3&#8201;hPa range. This method ensures robustness and flexibility in contiguous area estimation specific to subtropical high events. Results showed the index effectively reflects the position and intensity of the SAHP. The study reveals that latitudinal variability of the SAHP has a strong unimodal structure, whereas longitudinal variability exhibits a bimodal structure. Seasonal patterns of the index show noticeable changes, with winter (JJA) and spring (SON) months having relatively high index values compared to summer (DJF) and autumn (MAM) months, underscoring the intra&#8208;annual variability of the SAHP index. During ENSO events, the mean centroid position of the SAHP shifts significantly, moving westwards and polewards during El Ni&#241;o and showing greater stability during La Ni&#241;a. The index, with minimal computation requirements and flexibility, can be applied across diverse datasets, aiding in the assessment of future subtropical high changes. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication <style type="text/css"></style><span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</span> None eng geoscientificInformation