El Niño–Southern Oscillation (ENSO) Impact on Tea Production and Rainfall in South India

2020 ◽  
Vol 59 (4) ◽  
pp. 651-664
Author(s):  
Esack Edwin Raj ◽  
Rajagopal Raj Kumar ◽  
K. V. Ramesh
Keyword(s):  
Crop Yield ◽  
El Niño ◽  
South India ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Tea Production ◽  
Enso Phases

AbstractEl Niño–Southern Oscillation (ENSO) is an aperiodic oscillation of sea surface temperature (SST)-induced interannual rainfall variability in south India (SI) that has a direct impact on rain-fed agricultural production and the economy of the region. The study analyzed the influence of ENSO-related rainfall variability on crop yield of south Indian tea-growing regions (SITR) for the period of 1971–2015. The relationship between SST anomalies from June to August over the Niño-3 sector of the tropical Pacific Ocean and tea production anomalies of SI shows a positive correlation. However, SST has a negative relationship with rainfall in the regions of the southwest monsoon but not with the northeast monsoon region of the Nilgiris. The correlation between rainfall and crop yield in SI (r = 0.045) is positively weak and statistically insignificant (p > 0.05). Tea production is influenced more by the cold phase than the warm phase of ENSO, whereas rainfall is greatly influenced by the warm phase. Tea production across the regions indicated that none of the ENSO phase categories based on Niño-3 has significantly greater production than any of the other ENSO phases. Therefore, the predictability of tea production on the basis of ENSO phases is limited. Our findings highlight that the crop production of SITR appeared to be less responsive to the ENSO phases. This may be due to improvements in production technology that mitigated the problems associated with rainfall variability.

Citrus postbloom fruit drop risk in Southern Brazil as influenced by different El Niño Southern Oscillation (ENSO) phases

Agrometeoros ◽  
2020 ◽  
Vol 28 ◽  
Author(s):  
Henrique Boriolo Dias ◽  
Ana Raquel Soares-Colletti ◽  
Fernando Dill Hinnah ◽  
Paulo Cesar Sentelhas
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Southern Brazil ◽  
Fruit Drop ◽  
Enso Phases

Modulation of East African boreal fall rainfall: combined effects of the Madden Julian Oscillation (MJO) and El Niño Southern Oscillation (ENSO)

2021 ◽  
pp. 1-42
Keyword(s):  
East Africa ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rainfall Variability ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Combined Effects ◽  
Madden Julian Oscillation ◽  
East African

Abstract Climate variabilities can have significant impacts on rainfall in East Africa, leading to disruption in natural and human systems and affecting the lives of tens of millions of people. Subseasonal and interannual variabilities are critical components of total rainfall variability in the region. The goal of this study is to examine the combined effects of the Madden Julian Oscillation (MJO), operating at subseasonal timescale, and the El Niño Southern Oscillation (ENSO), operating at an interannual scale, on the modulation of East African boreal fall (October-November-December; OND) rainfall, commonly called the short rains. Composite analysis shows that daily rainfall responses depend on MJO phase and its interaction with ENSO state. In particular, MJO modulation of rainfall is generally stronger under El Niño conditions relative to ENSO neutral and La Niña conditions, leading to increased potential for daily precipitation excesses during wet MJO phases under El Niño. There is evidence for both dynamic and thermodynamic mechanisms associated with these impacts, including an increase in westerly moisture transport and easterly advection of temperature and moist static energy. Seasonal analysis shows that the frequency and intensity of wet MJO phases during an El Niño contribute notably to the seasonal total precipitation anomaly. This suggests that MJO can mediate El Niño’s impact on OND rainfall in East Africa.

scholarly journals Variability in lightning hazard over Indian region with respect to El Niño–Southern Oscillation (ENSO) phases

2021 ◽  
Vol 21 (8) ◽  
pp. 2597-2609
Author(s):  
Avaronthan Veettil Sreenath ◽  
Sukumarapillai Abhilash ◽  
Pattathil Vijaykumar
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Indian Subcontinent ◽  
Monsoon Season ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Lightning Flash ◽  
The Impact ◽  
Enso Phases

Abstract. The El Niño–Southern Oscillation (ENSO) modulates the lightning flash density (LFD) variability over India during premonsoon, monsoon and postmonsoon seasons. This study intends to shed light on the impact of ENSO phases on the LFD over the Indian subcontinent using the data obtained from Optical Transient Detector (OTD) and Lightning Imaging Sensors (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite. Results suggest the LFD over northeast India (NEI) and southern peninsular India (SPI) strengthened (weakened) during the warm (cold) phase of ENSO in the premonsoon season. During monsoon season, NNWI (north of northwest India) shows above (below) normal LFD in the cold (warm) ENSO phase. It is striking to note that there are three hot spots of LFD over the Indian land region which became more prominent during the monsoon seasons of the last decade. A widespread increase in LFD is observed all over India during the warm phase of ENSO in the postmonsoon season. A robust rise in graupel/snow concentration is found during the postmonsoon season over SPI in the ENSO warm phase, with the lowest fluctuations over the NEI and NNWI regions. The subtropical westerly jet stream is shifted south in association with the warm phase, accompanied by an increase in geopotential height (GPH) all over India for the same period. This exciting remark may explain the indirect influences of ENSO's warm phase on LFD during the postmonsoon season by pushing the mean position of the subtropical westerly towards southern latitudes. However, the marked increase in LFD is confined mostly over the NNWI in the cold ENSO phase.

scholarly journals Characteristics of Intense Convection in Subtropical South America as Influenced by El Niño–Southern Oscillation

2019 ◽  
Vol 147 (6) ◽  
pp. 1947-1966 ◽  
Author(s):  
Zachary S. Bruick ◽  
Kristen L. Rasmussen ◽  
Angela K. Rowe ◽  
Lynn A. McMurdie
Keyword(s):  
South America ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Jet Stream ◽  
The World ◽  
Thermodynamic Conditions ◽  
Enso Phases

Abstract El Niño–Southern Oscillation (ENSO) is known to have teleconnections to atmospheric circulations and weather patterns around the world. Previous studies have examined connections between ENSO and rainfall in tropical South America, but little work has been done connecting ENSO phases with convection in subtropical South America. The Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) has provided novel observations of convection in this region, including that convection in the lee of the Andes Mountains is among the deepest and most intense in the world with frequent upscale growth into mesoscale convective systems. A 16-yr dataset from the TRMM PR is used to analyze deep and wide convection in combination with ERA-Interim reanalysis storm composites. Results from the study show that deep and wide convection occurs in all phases of ENSO, with only some modest variations in frequency between ENSO phases. However, the most statistically significant differences between ENSO phases occur in the three-dimensional storm structure. Deep and wide convection during El Niño tends to be taller and contain stronger convection, while La Niña storms contain stronger stratiform echoes. The synoptic and thermodynamic conditions supporting the deeper storms during El Niño is related to increased convective available potential energy, a strengthening of the South American low-level jet (SALLJ), and a stronger upper-level jet stream, often with the equatorward-entrance region of the jet stream directly over the convective storm locations. These enhanced synoptic and thermodynamic conditions provide insight into how the structure of some of the most intense convection on Earth varies with phases of ENSO.

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