Rondrotiana BarimalalaGeorgia Institute of Technology | GT · School of Earth and Atmospheric Sciences
Rondrotiana Barimalala
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27
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Introduction
Publications
Publications (27)
In recent years, there has been an increasing need for climate information across diverse sectors of society. This demand has arisen from the necessity to adapt to and mitigate the impacts of climate variability and change. Likewise, this period has seen a significant increase in our understanding of the physical processes and mechanisms that drive...
Two consecutive failed rainy seasons in the southern part of Madagascar in 2019–21 had devastating impacts on the population, including an amplification of the ongoing food insecurity in the area. The drought events were second in severity only to the 1990–92 drought and were estimated in a previous study to have a return period of 135 years. In th...
Mozambique is highly dependent on subsistence agriculture. Thus a climatology of rainfall onset and cessation is derived together with their interannual variability and trends using gridded daily data and station data. Mean onset is found to occur from early to mid‐November over southernmost regions, mid‐ to late November over central regions and l...
Southern Madagascar recently experienced a severe food security crisis, made significantly worse by well below average rainfall from July 2019 to June 2021. This exceptional drought has affected a region with high pre-existing levels of vulnerability to food insecurity (subsistence agriculture and pastoralism in the region is rain-fed only), while...
The topography of Madagascar and the strength of the Mozambique Channel Trough (MCT) modulate summer rainfall over southern Africa. A strong MCT hinders the penetration of moisture bearing easterlies from the South Indian Ocean into the mainland, thus reducing rainfall there and vice versa for weak MCT summers. Given the link between the MCT and ra...
The impacts of the low level jets that form through the gaps in the topography in the Limpopo and Zambezi River Valleys (LRV and ZRV) on southern African climate are investigated. ERA-5 reanalysis data and numerical experiments using regional climate models reveal that the two valleys act as main gateways for southwest Indian Ocean-sourced moisture...
The Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6) assess the physical science basis of climate change. As part of that contribution,
this Technical Summary (TS) is designed to bridge between the comprehensive assessment of the WGI Chapters and its Summary for Policymakers (SPM). I...
The evidence for human influence on recent climate change strengthened from the IPCC Second Assessment Report to the IPCC Fifth Assessment Report, and is now even stronger in this asessment. The IPCC Second Assessment Report (1995) concluded ‘the balance of evidence suggests that there is a discernible human influence on global climate’. In subsequ...
Outputs from 25 regional climate models within the coordinated regional downscaling experiments—Africa are used to assess the impacts of the 1.5°C and 2°C global warming levels (GWLs) over Madagascar. A robust increase in the annual mean temperature ranging from 0.9°C to 1.2°C (1.3°C–1.8°C) is projected in the 1.5°C (2°C) GWL. The west and southwes...
The Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6) assess the physical science basis of climate change. As part of that contribution, this Technical Summary (TS) is designed to bridge between the comprehensive assessment of the WGI Chapters and its Summary for Policymakers (SPM). It...
The evidence for human influence on recent climate change strengthened from the IPCC Second Assessment Report to the IPCC Fifth Assessment Report, and is now even stronger in this assessment. The IPCC Second Assessment Report (1995) concluded ‘the balance of evidence suggests that there is a discernible human influence on global climate’. In subseq...
Southern African climate is under the influence of both tropical and subtropical systems which result in a complex region where important interactions co-exist over a large spectrum of spatiotemporal scales. The Angola Low (AL), situated on boundary between tropical and subtropical southern Africa, has been diagnosed as a key driver of moisture dis...
The Mozambique Channel Trough (MCT) is a cyclonic region prominent in austral summer in the central and southern Mozambique Channel. It first becomes evident in December with a peak in strength in February when the Mozambique Channel is warmest and the Mascarene High (MH) is located furthest southeast in the Indian Ocean basin. The strength and the...
Climate models provide a key component of climate risk information. However, it is difficult to use climate model output for Africa due to model biases and/or limited understanding of how models represent African regions.
Most climate models are developed outside of Africa, whilst many experts in African weather and climate have limited access to...
The rainfall mean state and variability of the tropical Southern Hemisphere are strongly affected by the Tropical Convergence Zones. Unlike the South Pacific and South Atlantic, the topography of Madagascar prevents, through the Mozambique Channel Trough, the direct transport of moisture from the Indian Ocean towards southern Africa
that feeds the...
Mesoscale sea surface temperature (SST) variability plays an important role in shaping local atmospheric boundary layers through thermodynamic processes. This study focuses on the upscaling effects of mesoscale SST gradients in sensitive areas on the southern Africa regional atmospheric circulation. Using regional atmospheric model sensitivity expe...
Current and future climate change poses a substantial threat to the African continent. Young scientists are needed to advance Earth systems science on the continent, but they face significant challenges.
The impact of sampling variability on the correlation between all-India rainfall (AIR) and the El Niño-Southern Oscillation is investigated in a large ensemble of seasonal climate simulations made using the European Centre for Medium-Range Weather Forecasting Ensemble Prediction System at T319 (64 km). The analyzed runs consist of 51 ensemble membe...
This study examines El Niño–Southern Oscillation (ENSO) prediction in Project Minerva, a recent collaboration between the Center for Ocean–Land–Atmosphere Studies (COLA) and the European Centre for Medium-Range Weather Forecasts (ECMWF). The focus is primarily on the impact of the atmospheric horizontal resolution on ENSO prediction, but the effect...
A series of recent papers showed that sea surface temperature (SST) anomalies in the south equatorial tropical Atlantic modulate
the interannual variability of the African and Indian monsoon rainfall. Physically this teleconnection can be explained by
a simple Gill-Matsuno mechanism. In this work, the output from five different models chosen within...
The focus of this paper is to assess the relative role of the north-south and east-west contrasts in atmospheric heating for the maintenance of the South Asian summer monsoon climatology. The juxtaposition of the Eurasian land mass and the Indian Ocean is responsible for the north-south contrast, while the greater diabatic heating above the western...
In recent studies we have shown that the tropical Atlantic exerts a considerable influence to both the Indian Ocean basin, modulating also the Indian summer monsoon. A warm (cold) tropical Atlantic Ocean forces a Gill-Matsuno-type quadrupole response with a low-level anticyclone (cyclone) located over India that weakens (strengthens) the Indian mon...
Recent studies found that tropical Atlantic variability may affect the climate in both the tropical Pacific and Indian Ocean basins, possibly modulating the Indian summer monsoon and Pacific ENSO events. A warm tropical Atlantic Ocean forces a Gill-Matsuno-type quadrupole response with a low-level anticyclone located over India that weakens the Ind...