Fig. 7: The relationship between equatorial wind anomalies, low-level absolute vorticity, and BoB LLC frequency during contrasting phases of ENSO.
From: ENSO influence on Bay of Bengal cyclogenesis confined to low latitudes
a Equatorial wind anomalies versus 850hPa absolute vorticity, and b Equatorial wind anomalies versus BoB LLC frequency. Both equatorial wind anomalies (averaged over 2.5°S–2.5°N, 83°E–95°E) and absolute vorticity anomaly (averaged over 5°S–10°N, 83°E–95°E) are normalised by its own standard deviation. The El Niño, La Niña and neutral ENSO years are marked in red, blue, and grey colours, respectively. Years are labelled using arrows to the points. The linear trend is shown as the orange line, and the grey shading indicates 95% confidence level in panel a. During El Niño and positive IOD years, equatorial westerlies weaken leading to reduced absolute vorticity and fewer number of LLCs. The reverse occurs during La Niña and negative IOD years.
