Interannual variation of summer monsoon rainfall over Nepal and its relation to Southern Oscillation Index

2000 ◽  
Vol 75 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
M. L. Shrestha
Keyword(s):  
Summer Monsoon ◽  
Interannual Variation ◽  
Southern Oscillation Index ◽  
Monsoon Rainfall ◽  
Southern Oscillation ◽  
Summer Monsoon Rainfall

scholarly journals Interannual Variation of the Summer Rainfall Center in the South China Sea

2017 ◽  
Vol 30 (19) ◽  
pp. 7909-7931 ◽  
Author(s):  
Tsing-Chang Chen ◽  
Jenq-Dar Tsay ◽  
Jun Matsumoto
Keyword(s):  
Summer Monsoon ◽  
Interannual Variation ◽  
Monsoon Rainfall ◽  
Monsoon Season ◽  
Summer Rainfall ◽  
The Philippines ◽  
Monsoon Trough ◽  
Summer Monsoon Rainfall ◽  
Tropical Depression ◽  
Easterly Wave

Abstract A northwest–southeast-oriented summer monsoon trough exists between northern Indochina and northwestern Borneo. Ahead of this the South China Sea (SCS) trough is located at a convergent center west of the Philippines, which provides an environment favorable for rain-producing synoptic systems to produce rainfall over this center and form the SCS summer rainfall center. Revealed from the x–t diagram for rainfall, this rainfall center is developed by multiple-scale processes involved with the SCS trough (TR), tropical depression (TY), interaction of the SCS trough with the easterly wave/tropical depression (EI), and easterly wave (EW). It is found that 56% of this rainfall center is produced by the SCS trough, while 41% is generated by the other three synoptic systems combined. Apparently, the formation of the SCS summer monsoon rainfall center is contributed to by these four rain-producing synoptic systems from the SCS and the Philippines Sea. The Southeast Asian summer monsoon undergoes an interannual variation and exhibits an east–west-oriented cyclonic (anticyclonic) anomalous circulation centered at the western tropical Pacific east of the Luzon Strait. This circulation change is reflected by the deepening (filling) of the SCS summer monsoon trough, when the monsoon westerlies south of 15°N intensify (weaken). This interannual variation of the monsoon westerlies leads to the interannual variation of the SCS summer monsoon rainfall center to follow the Pacific–Japan oscillation of rainfall. The rainfall amount produced over this rainfall center during the weak monsoon season is about two-thirds of that produced during the strong monsoon season. The rain-production ratio between TR and TY + EI + EW is 60:38 during the strong monsoon season and 47:49 during the weak monsoon season.

scholarly journals Impact of Madden-Julian oscillations on the Indian summer monsoon sub-divisional rainfalls

MAUSAM ◽  
2021 ◽  
Vol 59 (2) ◽  
pp. 195-210
Author(s):  
K. SEETHARAM
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Seasonal Variations ◽  
Monsoon Rainfall ◽  
Indian Summer Monsoon Rainfall ◽  
Southern Oscillation ◽  
Low Frequency ◽  
Summer Monsoon Rainfall ◽  
Dominant Mode ◽  
Oscillation Phenomenon

Indian summer monsoon rainfall exhibits inter-seasonal variations in the time scales of 2-7 years which are linked to quasi-biennial oscillations and El nino-Southern Oscillation phenomenon and also intra-seasonal variations in the time-scale of 30-60 days which are linked to activity of MJO which emerged as a dominant mode of intra-seasonal oscillations of Indian summer monsoon rainfall in addition to the other modes of low frequency oscillations. In this scenario, the inter and intra seasonal variability of 29 meteorological sub-divisional rainfalls has been investigated by correlating the MJO indices at 10 different longitudes covering Indian, Pacific and Atlantic Oceans with cumulative sub-divisional summer monsoon rainfall (1979 – 2000). The results were discussed.

scholarly journals El Nino, Southern Oscillation, equatorial eastern Pacific sea surface temperatures and summer monsoon rainfall in India

MAUSAM ◽  
2021 ◽  
Vol 49 (1) ◽  
pp. 103-114
Author(s):  
R. P. KANE
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
Monsoon Rainfall ◽  
El Nino ◽  
Southern Oscillation ◽  
Summer Monsoon Rainfall ◽  
Stratospheric Wind ◽  
India Summer Monsoon ◽  
Cold Events ◽  
India Summer Monsoon Rainfall

For the 120 yean (1871-1990), every year was designated as an El Nino (EN), or Southern Oscillation (SO), minimum or a combination of these, or none. For all India summer monsoon rainfall (ISMR), unambiguous ENSOW [SO and W (warm events) in the middle of the calendar year] seemed to be best associated with droughts and events of type C (cold events) were best associated with floods. However, some droughts occurred without the presence of EN related events and some floods occurred even in the presence of EN related events. In these cases, other parameters such as Eurasian snow cover or stratospheric wind QBO might have had a larger influence.

scholarly journals Timing of El Niño–Related Warming and Indian Summer Monsoon Rainfall

2008 ◽  
Vol 21 (11) ◽  
pp. 2711-2719 ◽  
Author(s):  
Chie Ihara ◽  
Yochanan Kushnir ◽  
Mark A. Cane ◽  
Alexey Kaplan
Keyword(s):  
Summer Monsoon ◽  
El Niño ◽  
Monsoon Rainfall ◽  
El Nino ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Summer Monsoon Rainfall ◽  
Equatorial Pacific ◽  
Central Pacific ◽  
Eastern Equatorial Pacific

Abstract The relationship between all-India summer monsoon rainfall (ISMR) and the timing of (El Niño–Southern Oscillation) ENSO-related warming/cooling is investigated, using observational data during the period from 1881 to 1998. The analysis of the evolutions of Indo-Pacific sea surface temperature (SST) anomalies suggests that when ISMR is not below normal despite the co-occurrence of an El Niño event, warming over the eastern equatorial Pacific starts from boreal winter and evolves early so that the western-central Pacific and Indian Ocean are warmer than normal during the summer monsoon season. In contrast, when the more usual El Niño–dry ISMR relationship holds, the eastern equatorial Pacific starts warming rapidly only about a season before the reference summer so that the western-central Pacific and Indian Oceans remain cold during the monsoon season.

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