A study of 2014 record drought in India with CFSv2 model: role of water vapor transport

Ramakrishna, S. S. V. S.; Rao, V. Brahmananda; Rao, B. R. Srinivasa; Dasari, Hari Prasad; Rao, Nellipudi Nanaji; Panda, Roshmitha

doi:10.1007/s00382-016-3343-9

Cited by 14 publications

(3 citation statements)

References 48 publications

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“…In general, over the tropics, the intensity of rainfall is associated with the convergence or divergence of water vapour flux (Rao et al ., ; Li et al ., ; Wei et al ., ; Ramakrishna et al ., ; Zolina et al ., ). Therefore, examining the amount of moisture over a broader area around the Red Sea and its probable origin is also of interest.…”

Section: Resultsmentioning

confidence: 98%

ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

Dasari

Langodan

Viswanadhapalli

et al. 2017

Intl Journal of Climatology

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The Red Sea convergence zone (RSCZ) is formed by opposite surface winds blowing from northwest to southeast directions at around 18 ∘ -19 ∘ N between October and January. A reverse-oriented, low-level monsoon trough at 850 hPa, known as the Red Sea trough (RST), transfers moisture from the southern Red Sea to RSCZ. The positions of the RSCZ and RST and the intensity of the RST have been identified as important factors in modulating weather and climatic conditions across the Middle East. Here, we investigate the influence of the El Niño southern oscillation (ENSO) on the interannual variability of RSCZ, RST, and regional rainfall during winter months. Our results indicate that El Niño (warm ENSO phase) favours a shift of the RSCZ to the north and a strengthening of the RST in the same direction. Conversely, during November and December of La Niña periods (cold ENSO phase), the RSCZ shift to the south and the RST strengthens in the same direction. During El Niño periods, southeasterly wind speeds increase (20-30%) over the southern Red Sea and northwesterly wind speeds decrease (10-15%) over the northern Red Sea. Noticeable increases in the number of rainy days and the intensity of rain events are observed during El Niño phases. These increases are associated with colder than normal air intrusion at lower levels from the north combined with warm air intrusion from the south over the RSCZ. Our analysis suggests that during El Niño winters, warmer sea surface temperatures and higher convective instability over the Red Sea favour local storms conditions and increase rainfall over the Red Sea and adjoining regions.

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Section: Resultsmentioning

confidence: 98%

ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

Dasari

Langodan

Viswanadhapalli

et al. 2017

Intl Journal of Climatology

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“…Significant changes in sensible heat fluxes are also noticeable over the AP during EP2; this is due to changes in surface air temperatures that have evidently strengthened the turbulence in boundary layer and thereby increased the PBLH (Figure 6b) and, subsequently, increased surface wind speed. The significant increase in aerosols over the AP could have important broader impact, as it may, for instance, modulate the Indian summer monsoon by enhancing the regional tropospheric temperature gradients (Jin et al, 2018;Ramakrishna et al, 2017;Vinoj et al, 2014). During EP2, the net short-(long-) wave radiation at the surface shows (Figures 5e and 5f) a decrease (increase) over the western AP and an increase (decrease) over the Ethiopia region.…”

Section: The Epochal Changes In Aod and Associated Climate Variablesmentioning

confidence: 99%

On the Recent Amplification of Dust Over the Arabian Peninsula During 2002–2012

et al. 2019

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Using available satellite observations and Modern‐Era Retrospective analysis for Research and Applications Version‐2 data sets for the period 1980–2016, this study reveals a summertime dust amplification over the Arabian Peninsula (AP) during about past two decades. Our results demonstrate a significant positive trend in summertime dust loading over the AP since the year 2002, with a maximum increase of 21% over the southern Red Sea. The increased summertime dust over the southern AP is attributed to the intensification of the remote dust transport from the Sahara Desert through Sudan by a strengthened Tokar Gap westerly jet and a general increased gustiness in the AP. Furthermore, increased both air and soil temperature and reduction in the soil moisture along with increased sensible heat flux led to increased local dryness in the AP and played a significant role in enhancing wind‐induced localized dust emissions therein. The associated changes in the AP include an enhancement of net radiative fluxes, particularly the long wave radiative flux.

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“…In the recent years, the use of coupled ocean-atmosphere models for climate and weather predictions in different timescales has been increased significantly (Bender and Ginis 2000;Hamill et al 2004;Palmer et al 2004;Bechtold et al 2008;Reichler and Kim 2008;Guilyardi et al 2009;Saha et al 2014a;Joseph et al 2015;Ramakrishna et al 2016;etc.). For the past few years, India Meteorological Department (IMD) made use of the predictions from Climate Forecast System version 2 (CFSv2, Saha et al 2006Saha et al , 2014a developed by National Center for Environmental Prediction (NCEP) and customized by Indian Institute of Tropical Meteorology (Ramu et al 2016) for issuing the seasonal and extended range forecasts of Indian monsoon rainfall.…”

Section: Introductionmentioning

confidence: 99%

On the relationship between the Indian summer monsoon rainfall and the EQUINOO in the CFSv2

et al. 2018

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Several recent studies have shown that positive (negative) phase of Equatorial Indian Ocean Oscillation (EQUINOO) is favourable (unfavourable) to the Indian summer monsoon. However, many ocean-atmosphere global coupled models, including the state-of-the-art Climate Forecast System (CFS) version 2 have difficulty in reproducing this link realistically. In this study, we analyze the retrospective forecasts by the CFS model for the period 1982-2010 with an objective to identify the reasons behind the failure of the model to simulate the observed links between Indian summer monsoon and EQUINOO. It is found that, in the model hindcasts, the rainfall in the core monsoon region was mainly due to westward propagating synoptic scale systems, that originated from the vicinity of the tropical convergence zone (TCZ). Our analysis shows that unlike in observations, in the CFS, majority of positive (negative) EQUINOO events are associated with El Niño (La Niña) events in the Pacific. In addition to this, there is a strong link between EQUINOO and Indian Ocean Dipole (IOD) in the model. We show that, during the negative phase of EQUINOO/IOD, northward propagating TCZs remained stationary over the Bay of Bengal for longer period compared to the positive phase of EQUINOO/IOD. As a result, compared to the positive phase of EQUINOO/IOD, during a negative phase of EQUINOO/IOD, more westward propagating synoptic scale systems originated from the vicinity of TCZ and moved on to the core monsoon region, which resulted in higher rainfall over this region in the CFS. We further show that frequent, though short-lived, westward propagating systems, generated near the vicinity of TCZ over the Bay moved onto the mainland were responsible for less number of break monsoon spells during the negative phase of EQUINOO/IOD in the model hindcasts. This study underlines the necessity for improving the skill of the coupled models, particularly CFS model, to simulate the links between EQUINOO/IOD and the Indian summer monsoon for reliable predictions of seasonal and intraseasonal variation of Indian summer monsoon rainfall.

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A study of 2014 record drought in India with CFSv2 model: role of water vapor transport

Cited by 14 publications

References 48 publications

ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

On the Recent Amplification of Dust Over the Arabian Peninsula During 2002–2012

On the relationship between the Indian summer monsoon rainfall and the EQUINOO in the CFSv2

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