5.3 Update on El Niño

A likely El Nino condition has appeared across the Pacific Ocean during the first month of 2019. Figure 1. illustrates the behavior of the standard Southern Oscillation Index (SOI) of the Australian Bureau of Meteorology (BOM) from January 2018 to January 2019. Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between about +7 and −7 generally indicate neutral conditions. 

During the current season, SOI decreased slightly from +3 in October to -0.1 in November, then increased to +9.3 in December, but dropped to -0.6 again in January 2019, indicating a likely El Nino condition.

Figure 5.5. Monthly SOI-BOM time series from January 2018 to January 2019[1]

The sea surface temperature anomalies in January 2019 for NINO3, NINO3.4, and NINO4 regions are +0.5°C, +0.5°C, and +0.7°C in sequence,  a litter warmer than 1961-1990 average according to BOM monitored (see Figure 5.7). Both of BOM and Japan Meteorological Agency[2] think that the warmer condition indicates a weak El Niño trend and their ENSO’s outlook lies at El Niño Watch in the following spring of Northern Hemisphere. CropWatch will keep on monitoring its condition.

Figure 5.6. Map of NINO Region[3]

Figure 5.7. January 2019 sea surface temperature departure from the 1961-1990 average[4]

Main Sources:

[1] http://www.bom.gov.au/climate/current/soi2.shtml

[2] https://ds.data.jma.go.jp/tcc/tcc/products/elnino/elmonout.html

[3] https://www.climate.gov/sites/default/files/Fig3_ENSOindices_SST_large.png

[4] http://www.bom.gov.au/climate/enso/wrap-up/archive/20190219.ssta_pacific_monthly.png?popup