Subseasonal-to-interannual variability of rainfall over New Caledonia (SW Pacific)

Moron, Vincent; Barbero, Renaud; Robertson, Andrew W.

doi:10.1007/s00382-015-2712-0

Cited by 10 publications

(14 citation statements)

References 44 publications

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“…Finally, the present-day NC rainfall interannual variability is strongly related to ENSO (Fischer 2004;Moron et al 2016;Nicet and Delcroix 2000). Several studies (e.g.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…1a). While the average annual rainfall is high (~ 5 mm.day −1 ), water is regarded as a vulnerable resource in New Caledonia since ~ 70% of the total rainfall occurs within ~ 15 days (Moron et al 2016), mainly during the first quarter of the year. Hill reservoirs and dams were built a decade ago to reduce the risks of water (including drinking water) shortages, but are now insufficient to meet the growing needs of various economic sectors, such as agriculture (https ://www.forum h2o.nc).…”

Section: Introductionmentioning

confidence: 99%

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Fine-scale rainfall over New Caledonia under climate change

Dutheil

Menkès²,

Lengaigne

et al. 2020

Clim Dyn

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Global climate models projections indicate no clear future rainfall changes over the Southwestern Pacific islands in response to anthropogenic forcing. Yet, these models have low (~ 100–200 km) spatial resolution and suffer from large systematic biases, such as the trademark “double ITCZ”. Here, 4 km-resolution simulations were used with a nested regional atmospheric model, which resolves the New Caledonian mountainous topography. The resulting present-day rainfall amount, spatial structure, seasonal cycle, and extremes compare much better with observations than at 20 km resolution. We applied projected changes from global climate models under the RCP8.5 scenario at the boundaries, following an approach that corrects both their present-day and projected sea surface temperature biases. Unlike climate models, our refined projections reveal an 18% decrease in annual mean rainfall over New Caledonia by 2080–2100, especially on the leeward side of the island (up to 30%) and during the hot season (that accounts for ~ 80% of the rainfall decrease). This drying is robust without bias correction, and much stronger than at ~ 20 km resolution. It is mainly driven by circulation changes. A weather regime classification further demonstrates that ~ 80% of the hot season drying relates to a strong anti-cyclonic and air subsidence anomalies centred on the north of NC, which reduces moisture convergence over the archipelago. The frequency and intensity of extreme precipitation events is also reduced by ~ 20% by 2080–2100. This drastic projected drying would have dramatic impacts on water resources and terrestrial ecosystems, pleading for carefully-planned adaptation policies for New Caledonia.

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“…Finally, the present-day NC rainfall interannual variability is strongly related to ENSO (Fischer 2004;Moron et al 2016;Nicet and Delcroix 2000). Several studies (e.g.…”

Section: Summary and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fine-scale rainfall over New Caledonia under climate change

Dutheil

Menkès²,

Lengaigne

et al. 2020

Clim Dyn

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“…Midlatitude highs and lows, and especially the Kermadec high, control the orientation of the prevailing trade winds, while tropical influences impact New Caledonia through the seasonal variations in the location of the South Pacific convergence zone (SPCZ, Griffiths et al 2003). Being located to the south of the mean position of the SPCZ, New Caledonia's weather is impacted by the frequent southward shifts of the SPCZ in the wet season, which bring increased precipitation (Lefort 2005;Moron et al 2016). Global modes of variability then modulate these climatological processes.…”

Section: Introductionmentioning

confidence: 99%

“…At the interannual time scale, El Niño-Southern Oscillation (ENSO) influences the orientation of the SPCZ (Vincent et al 2011;Salinger et al 2014) and the probability of occurrence of tropical cyclones, that is increased in La Niña phase and decreased in El Niño phase (Leroy and Wheeler 2008). At the subseasonal time scale, the Madden-Julian oscillation (MJO; Madden and Julian 1971) impacts wind patterns (Lefort 2005;Lefèvre et al 2010), while it is also responsible for shifts in the SPCZ (Matthews 2012;Moron et al 2016) and changes in the probability of observing a tropical cyclone (Leroy and Wheeler 2008). As a result, Leroy (2006) highlights an impact of the MJO on New Caledonia rainfall, and Moron et al (2016) also show a modulation of rainfall by the subseasonal variability, although they need to use a tailor-made OLR-based intraseasonal index centered on New Caledonia to demonstrate it.…”

Section: Introductionmentioning

confidence: 99%

“…At the subseasonal time scale, the Madden-Julian oscillation (MJO; Madden and Julian 1971) impacts wind patterns (Lefort 2005;Lefèvre et al 2010), while it is also responsible for shifts in the SPCZ (Matthews 2012;Moron et al 2016) and changes in the probability of observing a tropical cyclone (Leroy and Wheeler 2008). As a result, Leroy (2006) highlights an impact of the MJO on New Caledonia rainfall, and Moron et al (2016) also show a modulation of rainfall by the subseasonal variability, although they need to use a tailor-made OLR-based intraseasonal index centered on New Caledonia to demonstrate it. Moreover, the MJO not only impacts the daily rainfall but also the diurnal cycle around islands, as documented by several studies based on observations (Chen and Houze 1997;Sui et al 1997;Tian et al 2006;Suzuki 2009;Hidayat and Kizu 2009;Rauniyar and Walsh 2011;Oh et al 2012;Kanamori et al 2013;Peatman et al 2014) and model simulations (Birch et al 2016;Vincent and Lane 2017).…”

Section: Introductionmentioning

confidence: 99%

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Influence of Subseasonal Variability on the Diurnal Cycle of Precipitation on a Mountainous Island: The Case of New Caledonia

Specq

Bellon

Peltier

et al. 2019

Monthly Weather Review

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The relationship between the large-scale intraseasonal variability, synoptic wind regimes, and the local daily variability of precipitation over the main island of New Caledonia (southwest tropical Pacific) is investigated with a focus on the austral summer wet season (November–April). The average diurnal cycle of precipitation over the island is characterized by a sharp afternoon maximum around 1600 local time, with significant differences between the windward east coast, the leeward west coast, and the mountain range. The afternoon peak is related to the afternoon sea-breeze circulation and to the diurnal cycle of convection over land. In general, its magnitude follows the same evolution as the daily mean. In agreement with past studies, a clear modulation of the Madden–Julian oscillation (MJO) on both the diurnal cycle of precipitation and the probability of occurrence of four robust wind regimes can be identified in the New Caledonia region during the wet season. From the evidence that there is a qualitative correspondence between the effects of both the MJO phases and the wind regimes on features in the diurnal cycle of precipitation, a simple model is proposed to inspect the MJO forcing mediated by wind regimes on the diurnal variability of rain. The complete decomposition of the MJO impact shows that the modulation of diurnal cycle by the MJO relies on complex interactions between the MJO and synoptic winds that involve both large-scale MJO convective anomalies and MJO-induced modification of wind patterns.

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Weather patterns in Southeast Asia: Relationship with tropical variability and heavy precipitation

Howard

Thomas

Frame

et al. 2021

Quart J Royal Meteoro Soc

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Two sets of weather patterns describing variability in 850 hPa winds in Southeast Asia are presented and compared. Patterns are calculated using EOF/k-means clustering with and without imposing a separation between planetary-scale and regional-scale circulation features. The former are labelled as tiered patterns while the latter are referred to as flat. The ability of the patterns to distinguish between known modes of tropical circulation variability is examined. This includes climate modes such as the seasonal monsoons, the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) as well as sub-seasonal modes including cold surges, phases of the MJO and Boreal summer intraseasonal oscillation (BSISO), tropical cyclones, Borneo vortices and equatorial waves. All these modes are well captured by the weather patterns except for the equatorial waves and the IOD. The tiered patterns are shown to better describe large-scale modes of variability, while the flat patterns better describe the synoptic variability. Both sets of weather patterns are then used to study the likelihood of heavy precipitation depending on synoptic circulation by considering the regime-conditioned probability of high-percentile precipitation using the satellite-derived Global Precipitation Measurement (GPM) dataset. It is shown that the pattern centroids explain up to 10% of the seasonally anomalous precipitation over land, and that a perfect weather pattern forecast would outperform a perfect MJO forecast. These weather patterns show promising potential in extending the useful forecast range for the risk of heavy precipitation, dependent on their forecastability.

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Subseasonal-to-interannual variability of rainfall over New Caledonia (SW Pacific)

Cited by 10 publications

References 44 publications

Fine-scale rainfall over New Caledonia under climate change

Fine-scale rainfall over New Caledonia under climate change

Influence of Subseasonal Variability on the Diurnal Cycle of Precipitation on a Mountainous Island: The Case of New Caledonia

Weather patterns in Southeast Asia: Relationship with tropical variability and heavy precipitation

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