Seasonal prediction of Indian summer monsoon in India: The past, the present and the future

<p>The prediction of the onset date of the Indian Summer Monsoon (ISM) is crucial for effective agricultural planning and water resource management on the Indian subcontinent, with more than one billion inhabitants. Existing approaches focus on extended-range to subseasonal forecasts, i.e., provide skillful predictions of the ISM onset date at horizons of 10 to 60 days. Here we propose a method for ISM onset prediction and show that it has high forecast skill at longer, seasonal time scales. The method is based on recurrent neural networks and allows for ensemble forecasts to quantify uncertainties. Our approach outperforms state-of-the-art numerical weather prediction models at comparable or longer lead times. To our knowledge, there is no statistical forecasting approach at comparable, seasonal time scales. Our results suggest that predictability of the ISM onset emerges earlier than previously assumed.</p>

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On the relationship between Indian Ocean Dipole, Indian summer monsoon and ENSO

10.5194/egusphere-egu21-14562 ◽

2021 ◽

Author(s):

Annalisa Cherchi ◽

Pascal Terray ◽

Satyaban Bishoyi Ratna ◽

Virna Meccia ◽

Sooraj K.P.

Keyword(s):

Indian Ocean ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Indian Ocean Dipole ◽

Climate Models ◽

Southern Oscillation ◽

Global Climate ◽

Global Climate Models ◽

The Future ◽

The Indian Ocean

<p>The Indian Ocean Dipole (IOD) is one of the dominant modes of variability of the tropical Indian Ocean and it has been suggested to have a crucial role in the teleconnection between the Indian summer monsoon and El Nino Southern Oscillation (ENSO). The main ideas at the base of the influence of the IOD on the ENSO-monsoon teleconnection include the possibility that it may strengthen summer rainfall over India, as well as the opposite, and also that it may produce a remote forcing on ENSO itself. The Indian Ocean has been experiencing a warming, larger than any other basins, since the 1950s. During these decades, the summer monsoon rainfall over India decreased and the frequency of Indian Ocean Dipole (IOD) events increased. In the future the IOD is projected to further increase in frequency and amplitude with mean conditions mimicking the characteristics of its positive phase. Still, state of the art global climate models have large biases in representing IOD and monsoon mean state and variability, with potential consequences for properties and related teleconnections projected in the future. This works collects a review study of the influence of the IOD on the ISM and its relationship with ENSO, as well as new results on IOD projections comparing CMIP5 and CMIP6 models.</p>

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Changes in the Indian Summer Monsoon during the past 600 years: A high-resolution record from the Anshupa Lake, Upper Mahanadi Delta, Core Monsoon Zone of India

Journal of Asian Earth Sciences ◽

10.1016/j.jseaes.2021.105048 ◽

2021 ◽

pp. 105048

Author(s):

Chinmay Dash ◽

Rajasekhariah Shankar ◽

Pitambar Pati ◽

Busnur Rachotappa Manjunatha ◽

Rayees Ahmad Shah ◽

...

Keyword(s):

High Resolution ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

The Past

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Objective Definition of the Indian Summer Monsoon Onset*

Journal of Climate ◽

10.1175/2008jcli2675.1 ◽

2009 ◽

Vol 22 (12) ◽

pp. 3303-3316 ◽

Cited By ~ 114

Author(s):

Bin Wang ◽

Qinghua Ding ◽

P. V. Joseph

Keyword(s):

Indian Ocean ◽

Excellent Agreement ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Time Scale ◽

Rainy Season ◽

Arabian Sea ◽

Monsoon Onset ◽

Indian Peninsula ◽

The Past

Abstract The onset of the Indian summer monsoon (ISM) over the southern tip of the Indian peninsula [also known as monsoon onset over Kerala (MOK)] has been considered the beginning of India’s rainy season. The Indian Meteorological Department (IMD) makes an official prediction of ISM onset every year using a subjective method. Based on an analysis of the past 60-yr (1948–2007) record, the authors show that the onset date can be objectively determined by the beginning of the sustained 850-hPa zonal wind averaged over the southern Arabian Sea (SAS) from 5° to 15°N, and from 40° to 80°E. The rapid establishment of a steady SAS westerly is in excellent agreement with the abrupt commencement of the rainy season over the southern tip of the Indian peninsula. In 90% of the years analyzed, this simple and objective index has excellent agreement with the onset dates that are subjectively defined by the IMD. There are only 3 yr of the past 60 yr during which the two onset dates differ by more than 10 days, and none of them perfectly reflects the MOK. A prominent onset precursor on the biweekly time scale is the westward extension of the convection center from the equatorial eastern Indian Ocean toward the southeast Arabian Sea. On the intraseasonal time scale, the onset tends to be led by northeastward propagation of an intraseasonal convective anomaly from the western equatorial Indian Ocean. The objective determination of the onset based on the SAS low-level westerly is a characteristic representation of the complex process of the ISM onset. Given its objectiveness and its representation of the large-scale circulation, the proposed new onset definition provides a useful metric for verifying numerical model performance in simulating and predicting the ISM onset and for studying predictability of interannual variations of the onset.

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Seasonal prediction of Indian summer monsoon rainfall in NCEP CFSv2: forecast and predictability error

Climate Dynamics ◽

10.1007/s00382-015-2703-1 ◽

2015 ◽

Vol 46 (7-8) ◽

pp. 2305-2326 ◽

Cited By ~ 26

Author(s):

Samir Pokhrel ◽

Subodh Kumar Saha ◽

Ashish Dhakate ◽

Hasibur Rahman ◽

Hemantkumar S. Chaudhari ◽

...

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Monsoon Rainfall ◽

Indian Summer Monsoon Rainfall ◽

Seasonal Prediction ◽

Summer Monsoon Rainfall

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Late Holocene Indian Summer Monsoon Variations Recorded at Lake Erhai, Southwestern China

Quaternary Research ◽

10.1016/j.yqres.2014.12.004 ◽

2015 ◽

Vol 83 (2) ◽

pp. 307-314 ◽

Cited By ~ 21

Author(s):

Hai Xu ◽

Xinying Zhou ◽

Jianghu Lan ◽

Bin Liu ◽

Enguo Sheng ◽

...

Keyword(s):

Grain Size ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Late Holocene ◽

Southwestern China ◽

Sediment Grain Size ◽

The Past ◽

Pollen Concentrations ◽

Lake Erhai ◽

Elemental Contents

In this study we report changes in Indian summer monsoon (ISM) intensity during the past ~ 3500 yr inferred from proxy indices at Lake Erhai, southwestern China. Both the pollen concentrations and other proxy indices, including sediment grain size, total organic carbon contents (TOC), and elemental contents (e.g., Fe, Al), clearly indicate a long term decreasing trend in ISM intensity over the late Holocene. During the period from approximately AD 750 to AD 1200, pollen concentrations of conifer and broadleaf trees, and herbs reached the lowest levels over the past ~ 3500 yr; while the pollen percentages of both herbs and broadleaf trees increased, suggesting a significant medieval drought. The grain size, TOC, and elemental contents also support an arid climate during the medieval period. The Little Ice Age (LIA) at Lake Erhai was characterized as cold and wet. The medieval and LIA climatic patterns at Lake Erhai were similar to those over most of the ISM areas, but anti-phase with those over East Asian summer monsoon (EASM) areas. We suspect that sea surface temperature variations in the Indo-Pacific oceans and the related land-sea thermal contrasts may be responsible for such hydroclimatic differences between EASM and ISM areas.

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