First Seasonal El Nino Thresh Hold Reached – Now For A Full Fledged El Nino NOAA Criteria Requires ONI >= +0.5ºC For A Continuous Period Of Four More Months

First Seasonal El Nino Thresh Hold Reached – Now For A Full Fledged El Nino NOAA Criteria Requires ONI >= +0.5ºC For A Continuous Period Of Four More Months

El Nino થ્રેશ હોલ્ડ પહેલા ચરણે પહોંચ્યું – હવે વિધિવત El Nino માટે NOAA ના નિયમો મુજબ સળંગ ચાર મહિના ONI >= +0.5ºC રહેવું જોઈએ

Enso Status on 5th July 2023

The first El Nino thresh hold has been reached for AMJ 2023 with ONI at +0.5ºC. Earlier Enso Neutral conditions had prevailed in the earlier three 3-monthly seasons JFM ONI at -0.4ºC, FMA ONI at -0.1ºC and MAM 2023 ONI at +0.2ºC.

Ashok Patel’s Analysis & Commentary :

The first El Nino thresh hold has been reached for AMJ 2023 with ONI at +0.5ºC. Earlier Enso Neutral conditions had prevailed in the earlier three 3-monthly seasons JFM ONI at -0.4ºC, FMA ONI at -0.1ºC and MAM 2023 ONI at +0.2ºC. NOAA criteria stipulates that a Full fledged El Nino requires five 3-monthly seasons with ONI => 0.5C, which can only be achieved earliest at the end of October 2023 since the AMJ is at First El Nino thresh hold with ONI at +0.5ºC . Hence it can be concluded that a full fledged El Nino is not possible during the Indian Southwest Monsoon season which ends at the end of September 2023. The other development is that SOI is currently in the Neutral territory after having been in negative zone last month. El Nino requires SOI to be in the negative zone. Pacific Ocean and atmosphere have yet to become fully coupled, as occurs during El Niño events

Indian Monsoon & Enso relationship for India:

Based on earlier more than 100 years weather Data for Indian Summer Monsoon, The Average Rainfall in an El Nino years is 94% of LPA while in La Nina Years it has been 106 % of LPA for the whole country. Monsoon Rainfall over India had been +106% of LPA at the end of 30th September 2022. El Nino or La Nina may affect the Monsoon differently for different Regions of India and warrants research for concrete co-relations for each region of India if any.

અશોક પટેલ નું તારણ અને વિશ્લેષણ :

AMJ 2023 નું ONI +0.5ºC હોય El Nino પહેલા ચરણે (પહેલા ત્રિમાસિક) પહોંચ્યું. આની પહેલા ના 3 ત્રિમાસિક સિઝન માં જે JFM ONI -0.4ºC, FMA ONI -0.1ºC અને MAM 2023 ONI +0.2ºC હતા જે Enso Neutral હતા. પહેલી ત્રિમાસિક સીઝન El Nino થ્રેશ હોલિડે પહોંચ્યું હોય NOAA ના નિયમો મુજબ હવે આવા 4 મહિના El Nino થ્રેશ હોલ્ડ જળવાય રહેવો જોઈએ તો વહેલા માં વહેલું ઓક્ટોબર 2023 માં વિધિવત El Nino પ્રસ્થાપિત થઇ શકે. ત્યાં સુધી માં ઇન્ડિયા નું ચોમાસુ સપ્ટેમ્બર 2023 માં પૂરું થઇ જશે. El Nino સાથે સંકળાયેલ પરિબળ SOI છે. જૂન આખર માં SOI ન્યુટ્રલ ઝોન માં હતું જે મે મહિના આખર માં નેગેટિવે ઝોન માં હતું. એલ નિનો માટે SOI નેગેટિવ ઝોન માં હોવું જરૂરી છે. પ્રશાંત મહાસાગર અને તેની ઉપર નું વાતાવરણ હજુ સંપૂર્ણ રીતે જોડાયેલા નથી, જેમ કે El Nino ઘટનાઓ દરમિયાન થાય છે.

આગળ ના 100 વર્ષ થી વધુ ની શરેરાશ પ્રમાણે એલ નિનો વર્ષ માં ભારતીય ચોમાસુ 94% રહેલ છે, જયારે લા નિના વર્ષ માં ચોમાસુ 106% રહેલ છે. ભારતીય ચોમાસા માટે વિવિદ્ધ પરિબળો પૈકી નું એલ નિનો/લા નિના ફક્ત એક પરિબળ છે. ભારત ના અલગ અલગ વિસ્તારો ના ચોમાસા પર એલ નિનો/લા નિના ની અસર એક સરખી નથી થતી, જે હાલ રિસર્ચ નો ઠોસ વિસય છે.

How ONI is determined:

The ONI is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO. Defined as the three-month running-mean SST departures in the Niño 3.4 region. Departures are based on a set of further improved homogeneous historical SST analyses (Extended Reconstructed SST – ERSST.v5).

NOAA Operational Definitions for El Niño and La Niña, El Niño: characterized by a positive ONI greater than or equal to +0.5ºC. La Niña: characterized by a negative ONI less than or equal to -0.5ºC. By historical standards, to be classified as a full-fledged El Niño or La Niña episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.

CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST departures meet or exceed +/- 0.5ºC along with consistent atmospheric features. These anomalies must also be forecast to persist for 3 consecutive months.

The Climate Prediction Center (CPC) is a United States Federal Agency that is one of the NECP, which are a part of the NOAA

The last La Nina 2021-23 ONI Index were JAS 2021 -0.5ºC ASO 2021 -0.7ºC SON 2021 -0.8ºC, OND 2021 -1.0ºC, NDJ 2021 -1.0ºC, DJF 2022 -1.0ºC, JFM 2022 -0.9ºC, FMA 2022 -1.0ºC, MAM 2022 -1.1ºC, AMJ 2022 -1.0ºC, MJJ 2022 -0.9ºC, JJA -0.8ºC, JAS 2022 -0.9ºC, ASO 2022 -1.0ºC, SON 2022 -1.0ºC, OND 2022 -0.9ºC, NDJ 2023 -0.8ºC, DJF 2023 -0.7ºC and the last Enso Neutral ONI Index are JFM 2023 -0.4ºC, FMA 2023 -0.1ºC, MAM 2023 +0.2ºC and now the El Nino thresh hold ONI Index AMJ 2023 +05ºC.

Latest Oceanic Nino Index Graph Shows
First El Nino Thresh Hold Achieved End Of June 2023

The Table below shows the monthly SST of Nino3.4 Region and the Climate adjusted normal SST and SST anomaly from July 2021. Climate Base 1991-2020. ERSST.v5

Period    Nino3.4 ClimAdjust
YR   MON  Temp.ºC Temp.ºC ANOM ºC


2021   7   26.90   27.29   -0.39
2021   8   26.32   26.86   -0.53
2021   9   26.16   26.72   -0.55
2021  10   25.78   26.72   -0.94
2021  11   25.76   26.70   -0.94
2021  12   25.54   26.60   -1.06
2022   1   25.61   26.55   -0.95
2022   2   25.88   26.76   -0.89
2022   3   26.33   27.29   -0.97
2022   4   26.72   27.83   -1.11
2022   5   26.83   27.94   -1.11
2022   6   26.98   27.73   -0.75
2022   7   26.60   27.29   -0.70
2022   8   25.88   26.86   -0.97
2022   9   25.65   26.72   -1.07
2022  10   25.73   26.72   -0.99
2022  11   25.80   26.70   -0.90
2022  12   25.75   26.60   -0.86
2023   1   25.84   26.55   -0.71
2023   2   26.30   26.76   -0.46
2023   3   27.19   27.29   -0.11
2023   4   27.96   27.83    0.14
2023   5   28.40   27.94    0.46
2023   6   28.54   27.73    0.81

Indications and analysis of various International Weather/Climate agencies monitoring ENSO conditions is depicted hereunder:

Summary by: Climate Prediction Center / NCEP  Dated 3rd July 2023

ENSO Alert System Status: El Niño Advisory
El Niño conditions are observed.*
Equatorial sea surface temperatures (SSTs) are above average across the eastcentral and eastern Pacific Ocean. The tropical Pacific atmospheric anomalies are consistent with weak El Niño conditions.
El Niño conditions are expected to gradually strengthen into the Northern Hemisphere winter 2023-24.*

* Note: These statements are updated once a month (2nd Thursday of each month) in association
with the ENSO Diagnostics Discussion, which can be found by clicking here.

Recent (preliminary) Southern Oscillation Index values as per The Long Paddock – Queensland Government.

30 Days average SOI was -3.19 at the end of June 2023 and was +0.95 on 4th July 2023 as per The Long Paddock – Queensland Government and 90 Days average SOI was -5.65 on 4th July 2023. The SOI has come back to neutral zone.

Southern Oscillation Index

As per BOM, Australia:

The 30-day Southern Oscillation Index (SOI) for the period ending 2 July 2023 was +1.1, returning to the neutral range over the past fortnight. Value for the 90-day SOI was −5.5. Both the 30-day and 90-day SOI have shown a steady decrease in magnitude over the past month.

Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.

As per BOM – Australia 4th July 2023