Diurnal Cycle in Different Weather Regimes and Rainfall Variability over Borneo Associated with ENSO

Qian, Jian‐Hua; Robertson, Andrew W.; Moron, Vincent

doi:10.1175/jcli-d-12-00178.1

Cited by 92 publications

(98 citation statements)

References 34 publications

(67 reference statements)

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“…In La Niña and negative IOD years, larger moisture transport from warmer sea water enhances diurnal cycle rainfall, which leads to a less clear dry season and flood disasters during cold surges and/or MJO active phases in the rainy season (e.g., Wu et al 2007Wu et al , 2013Matsumoto et al 2017). These results are essentially consistent with independent similar studies by Qian (2008) and Qian et al (2013). Decadal or longer-scale rainfall trends (e.g., Endo et al 2009;Villafuerte and Matsumoto 2015) should also appear through amplitude modulations of the diurnal cycles associated with variations of SST and moisture transport.…”

Section: Diurnal Cycle Observed Around the Imc Coastlinessupporting

confidence: 92%

Maritime continent coastlines controlling Earth’s climate

Yamanaka

Ogino

et al. 2018

Prog Earth Planet Sci

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During the Monsoon Asian Hydro−Atmosphere Scientific Research and Prediction Initiative (MAHASRI; 2006-16), we carried out two projects over the Indonesian maritime continent (IMC), constructing the Hydrometeorological Array for Intraseasonal Variation−Monsoon Automonitoring (HARIMAU; 2005-10) radar network and setting up a prototype institute for climate studies, the Maritime Continent Center of Excellence (MCCOE; 2009-14). Here, we review the climatological features of the world's largest "regional" rainfall over the IMC studied in these projects. The fundamental mode of atmospheric variability over the IMC is the diurnal cycle generated along coastlines by land−sea temperature contrast: afternoon land becomes hotter than sea by clear-sky insolation before noon, with the opposite contrast before sunrise caused by evening rainfall-induced "sprinkler"-like land cooling (different from the extratropical infrared cooling on clear nights). Thus, unlike the extratropics, the diurnal cycle over the IMC is more important in the rainy season. The intraseasonal, seasonal to annual, and interannual climate variabilities appear as amplitude modulations of the diurnal cycle. For example, in Jawa and Bali the rainy season is the southern hemispheric summer, because land heating in the clear morning and water vapor transport by afternoon sea breeze is strongest in the season of maximum insolation. During El Niño, cooler sea water surrounding the IMC makes morning maritime convection and rainfall weaker than normal. Because the diurnal cycle is almost the only mechanism generating convective clouds systematically near the equator with little cyclone activity, the local annual rainfall amount in the tropics is a steeply decreasing function of coastal distance (e-folding scale 100-300 km), and regional annual rainfall is an increasing function of "coastline density" (coastal length/land area) measured at a horizontal resolution of 100 km. The coastline density effect explains why rainfall and latent heating over the IMC are twice the global mean for an area that makes up only 4% of the Earth's surface. The diurnal cycles appearing almost synchronously over the whole IMC generate teleconnections between the IMC convection and the global climate. Thus, high-resolution (<< 100 km; << 1 day) observations and models over the IMC are essential to improve both local disaster prevention and global climate prediction.

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Section: Diurnal Cycle Observed Around the Imc Coastlinessupporting

confidence: 92%

Maritime continent coastlines controlling Earth’s climate

Yamanaka

Ogino

et al. 2018

Prog Earth Planet Sci

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“…The strength of land-sea and mountain-valley wind regimes is also modulated by the ambient, or background, winds (Miller et al 2003, and references therein;Qian et al 2010Qian et al , 2013. Pointwise regression and reduced incidence of thunderstorms over land, in agreement with the observations of Fujita et al (2011) and Qian et al (2013).…”

Section: Lightning Variability: Impact Of Clouds and Low-level Windsmentioning

confidence: 98%

Diurnal Lightning Variability over the Maritime Continent: Impact of Low-Level Winds, Cloudiness, and the MJO

Virts

Wallace

Hutchins

et al. 2013

Journal of the Atmospheric Sciences

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Lightning over the Maritime Continent exhibits a pronounced diurnal cycle. Daytime and evening lightning occurs near coastlines and over mountain slopes, driven by sea and valley breezes. Nocturnal and morning thunderstorms are touched off where land breezes or mountain breezes converge or by gravity waves propagating away from regions of vigorous afternoon convection. In this study, the modulation of the diurnal cycle of lightning and precipitation by 850-hPa winds, cloudiness, and the Madden-Julian oscillation (MJO) is investigated using observations from the World Wide Lightning Location Network (WWLLN) and the Tropical Rainfall Measuring Mission (TRMM) satellite. The 850-hPa wind speed and area-averaged cloudiness are shown to be negatively correlated with day-to-day lightning frequency over land, and thunderstorm occurrence is suppressed windward of, and enhanced leeward of, mountain ranges. Lightning and environmental conditions are similarly related in the MJO. During break periods, the regular diurnal cycle of lightning is enhanced where ambient low-level winds are easterly but abnormally weak-in the Strait of Malacca, over western and southern Borneo and the adjacent seas, and in the region of nocturnal thunderstorms to the west of Sumatra and Java. When the active, cloudy phase of the MJO, accompanied by low-level westerly winds, passes over the Maritime Continent, the regular diurnal cycle of lightning is enhanced leeward (to the east) of the mountains of Java, Borneo, and the Malay Peninsula. The spatial patterns of lightning and rainfall anomalies are broadly similar, but lightning anomalies tend to be more concentrated near coastlines.

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“…The prominent contrast of wet condition in western Borneo and anomalously dry condition in northern Borneo during DJF of an El Niño event was also highlighted in Juneng and Tangang () and Qian et al . (). However, the centre of the wet region is located over west of Kalimantan and Kuching is situated in between these two contrasting areas.…”

Section: Composites Of Precipitation Extremes During El Niño and La Niñamentioning

confidence: 99%

“…Furthermore, we also suggest that the wet tendency over west Kalimantan during DJF of El Niño, as discussed earlier and highlighted in Juneng and Tangang () and Qian et al . (), is contributed by this moisture convergence.…”

Section: Precipitation Extremes During Different Intensities Of El Nimentioning

confidence: 99%

Characteristics of precipitation extremes in Malaysia associated with El Niño and La Niña events

Tangang

Farzanmanesh

Mirzaei

et al. 2017

Intl Journal of Climatology

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This study investigates the El Niño‐Southern Oscillation (ENSO)‐related seasonal variations in precipitation extremes based on the observed daily precipitation dataset of 23 meteorological stations in Malaysia, spanning a period of 46 years from 1966 to 2011. The extreme indices were a subset of the Expert Team for Climate Change Detection and Indices (ETCCDI) that covers the duration, frequency and intensity aspects of precipitation extremes. Seasonal composites of ‘El Niño minus neutral’ and ‘La Niña minus neutral’ years of these indices were computed based on El Niño and La Niña occurrences during the period. The results showed that the ENSO‐related variations in precipitation extremes were generally coherent with the variations in total precipitation. Generally, dry (wet) precipitation extremes tended to enhance during El Niño (La Niña); however, this was dependent on season and location. The El Niño and La Niña influences on precipitation extremes were not entirely linear. While the impacts of El Niño and La Niña were generally opposite for most locations and seasons, there were cases where both exerted in‐phase influences. The impacts were also dependent on the intensity of the event itself. While the El Niño impacts were generally coherent across different intensities, La Niña can have entirely different impacts among different categories. During December–January–February (DJF), strong (moderate) La Niña caused a significant decrease (increase) in wet precipitation extremes over the Peninsular Malaysia. This was related to the broadening (narrowing and westward displacement) of the anomalous cyclonic circulation over the western north Pacific during strong (moderate) La Niña. Hence, the likelihood for widespread flooding over the east coast of the Peninsular Malaysia during DJF increases during moderate but not during strong La Niña events.

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Diurnal Cycle in Different Weather Regimes and Rainfall Variability over Borneo Associated with ENSO

Cited by 92 publications

References 34 publications

Maritime continent coastlines controlling Earth’s climate

Maritime continent coastlines controlling Earth’s climate

Diurnal Lightning Variability over the Maritime Continent: Impact of Low-Level Winds, Cloudiness, and the MJO

Characteristics of precipitation extremes in Malaysia associated with El Niño and La Niña events

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