Enso Status on 5th October 2022
JAS 2022 ONI Index is -0.9ºC. The ‘Double Dip La Nina’ continues to persist at the end of September 2022. Southwest Monsoon Rainfall over India has been +106% of LPA at the end of 30th September 2022.
JAS 2022 ONI ઈન્ડેક્સ -0.9ºC. ‘ડબલ ડીપ લા નીના’ હજુ ચાલુ છે. દક્ષિણ પશ્ચિમ ચોમાસા માં દેશ લેવલ માં વાર્ષિક શરેરાશ વરસાદ ના 106% વરસાદ થયેલ છે.
Ashok Patel’s Analysis & Commentary :
Using NOAA Criteria, the La Nina thresh hold was first met in JAS 2021 with Oni Index of -0.5ºC, however, the full fledged La Nina event was confirmed at the end of January 2022 having fulfilled the five consecutive overlapping 3-monthly seasons with ONI less than or equal to –0.5ºC. La Nina has continued for over a year, September 2022 being the 13th 3-monthly season with JAS 2022 at –0.9ºC. This La Nina event is called a ‘Double Dip La Nina’. See https://www.noaa.gov/news/double-dip-la-nina-emerges wherein NOAA mentions “Consecutive La Ninas following a transition through ENSO neutral conditions are not uncommon and can be referred to as a “double-dip.”
The First La Nina event was in 2020-21 which was followed by a second La Nina the current event of 2021-22 with a transition through Enso Neutral Conditions in 2021.
The Double Dip La Nina is expected to continue for some more Months.
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. El Nino or La Nina may affect the Monsoon differently for different Regions of India and the same is being researched for some concrete co-relations.
અશોક પટેલ નું તારણ અને વિશ્લેષણ :
NOAA માપદંડ મુજબ ‘લા નીના’ વ્યાખ્યા ની પહેલી સિઝન JAS 2021 માં શરુ થઇ અને વિધિવત ‘લા નીના’ જાન્યુઆરી 2022 ના પ્રસ્થાપિત થયું કહેવાય કે જયારે સળંગ 5 ત્રિમાસિક સીઝન માં ONI ઈન્ડેક્સ -0.5C કે તેની નીચે રહેલ. ‘લા નીના’ એક વરસ થી વધુ સમય થયા ચાલુ છે. સપ્ટેમ્બર 2022 આખર માં કુલ 13 ત્રિમાસિક સીઝન થી ‘લા નીના’ ચાલુ છે, જેમાં JAS 2022 નું ઓની ઈન્ડેક્સ -0.9ºC છે. NOAA એવું જણાવે છે આ લિંક માં કે બે સળંગ લા નીના વચ્ચે એન્સો ન્યુટ્રલ સ્થિતિ આવે તો તેને ‘ડબલ ડીપ લા નીના’ કહેવાય. પહેલો ‘લા નીના’ 2020-21 માં થયેલ ત્યાર બાદ એન્સો ન્યુટ્રલ પરિસ્થિતિ 2021 માં થયેલ અને ત્યાર બાદ સળંગ બીજો ‘લા નીના’ 2021-22 થયેલ જે હજુ ચાલુ છે. આ પ્રકિયા ને ‘ડબલ ડીપ લા નીના’ કહેવાય. હજુ આ ‘ડબલ ડીપ લા નીના’ પરિસ્થિતિ અમુક મહિના ચાલુ રહેશે.
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). Explanation about ERSST.v5 is given here.
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
Current La Nina 2021-22 all ONI Index are JAS 2021 -0.5ºC ASO 2021 -0.7ºC SON 2021 -0.8ºC, OND 2021 -1.0ºC, NDJ 2022 -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 and JAS 2022 -0.9ºC.
Latest Oceanic Nino Index Graph Shows
Double Dip La Nina 2021-22 Exists End Of September 2022
The Table below shows the monthly SST of Nino3.4 Region and the Climate adjusted normal SST and SST anomaly from June 2020. Climate Base 1991-2020. ERSST.v5
Period Nino3.4 ClimAdjust YR MON Temp.ºC Temp.ºC ANOM ºC 2020 6 27.39 27.73 -0.34 2020 7 26.99 27.29 -0.30 2020 8 26.27 26.86 -0.59 2020 9 25.89 26.72 -0.83 2020 10 25.46 26.72 -1.25 2020 11 25.28 26.70 -1.42 2020 12 25.45 26.60 -1.15 2021 1 25.56 26.55 -0.99 2021 2 25.76 26.76 -1.00 2021 3 26.50 27.29 -0.80 2021 4 27.11 27.83 -0.72 2021 5 27.48 27.94 -0.46 2021 6 27.45 27.73 -0.28 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 25.60 26.55 -0.95 2022 2 25.87 26.76 -0.90 2022 3 26.32 27.29 -0.98 2022 4 26.71 27.83 -1.12 2022 5 26.82 27.94 -1.12 2022 6 26.97 27.73 -0.76 2022 7 26.59 27.29 -0.70 2022 8 25.87 26.86 -0.98 2022 9 25.62 26.72 -1.09
Southern Oscillation Index
As per BOM, Australia:
The 30-day Southern Oscillation Index (SOI) to 3rd October 2022 was +19.2 and is considered in the La Nina zone.
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.
Recent (preliminary) Southern Oscillation Index values as per The Long Paddock – Queensland Government.
30 Days average SOI was +18.89 at the end of September 2022 and was +19.49 on 5th October 2022 as per The Long Paddock – Queensland Government and 90 Days average SOI was +12.40 on 5th October 2022.
SOI Monthly graph up to September 2022 as per The Long Paddock – Queensland Government.
Summary by: Climate Prediction Center / NCEP Dated 3rd October 2022
ENSO Alert System Status: La Niña Advisory
La Niña is present.*
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean. The tropical Pacific atmosphere is consistent with La Niña. La Niña is favored to continue through Northern Hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.*
* 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.
As per BOM – Australia 27th September 2022
ENSO outlooks
The ENSO Outlook continues at LA NIÑA. Sea surface temperatures in the tropical Pacific remain near La Niña thresholds, with corresponding changes in the overlying atmosphere.
The majority of models predict an easing of the La Niña in early 2023, suggesting a relatively short-lived event; ENSO events typically decay during the southern hemisphere autumn.
(Note: Autumn is with reference to Southern Hemisphere)
