Relationship between intraseasonal oscillation and diurnal variation of summer rainfall over the South China Sea

Ho, Chin Siong; Park, Myung‐Sook; Choi, Yun-Sang; Takayabu, Yukari N.

doi:10.1029/2007gl031962

Cited by 21 publications

(41 citation statements)

References 13 publications

(28 reference statements)

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“…The organisation of convection into mesoscale convective systems is also a strong function of the time of day, especially over the ocean (Nesbitt and Zipser, 2003). The diurnal cycle is further complicated by interactions with intraseasonal variability such as the Madden-Julian Oscillation (MJO; Tian et al, 2006;Ichikawa and Yasunari, 2006Ho et al, 2008). Such scale interactions are an integral part of the convection, precipitation and circulation characteristics of the region (Sui and Lau, 1992;Mapes and Houze, 1993;Chen et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

The diurnal cycle of precipitation over the Maritime Continent in a high‐resolution atmospheric model

Love

Matthews

Lister

2011

Quart J Royal Meteoro Soc

177

200

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Climate models can exhibit systematic errors in their mean precipitation over the Maritime Continent of the Indonesian archipelago at the heart of the tropical warm pool. These can often be traced back to an erroneous simulation of the diurnal cycle, and can lead to errors in global climate, through planetary wave propagation. Here, we examine the simulation of the diurnal cycle over the Maritime Continent in a series of high-resolution integrations of the UK Met Office atmospheric model, with horizontal resolutions of 40 and 12 km (where the convection is parametrised) and 4 km (where the convection is explicitly resolved), as part of the Cascade project. In these models, the vertical heating profile over the islands changes from a convective profile with a mid-tropospheric maximum in the early afternoon to a more stratiform profile with upper-tropospheric heating and mid-tropospheric cooling later. The convective heating profile forces a first internal mode gravity wave that propagates rapidly offshore; the deep warm anomalies behind its downwelling wavefront suppress convection offshore during early afternoon. The stratiform heating profile forces a gravity wave with a higher-order vertical mode that propagates slowly offshore later in the afternoon. This mode has a negative, destabilising temperature anomaly in the mid-troposphere. Together with the convergence zone between the wave fronts of the two modes, favourable conditions are created for offshore convection. In the 4 km explicit convection model, the offshore convection responds strongly to this gravity wave forcing, in agreement with observations, supporting a gravity wave-convection paradigm for the diurnal cycle over the Maritime Continent. However, the convective response in the lower-resolution models is much less coherent, leading to errors in the diurnal cycle and mean precipitation.

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Section: Introductionmentioning

confidence: 99%

The diurnal cycle of precipitation over the Maritime Continent in a high‐resolution atmospheric model

Love

Matthews

Lister

2011

Quart J Royal Meteoro Soc

177

200

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“…In addition, the diurnal cycle of rainfall in southeastern China and the South China Sea may be modulated greatly by the land and sea breeze, which is characterized by diurnal circulation with a rising (sinking) motion in the late afternoon over warm continents (adjacent to cool sea waters) and the reversed circulation during the early morning [16,17].…”

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confidence: 99%

Diurnal Variation of Rainfall Associated with Tropical Depression in South China and its Relationship to Land-Sea Contrast and Topography

Yuchun

2013

Atmosphere

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Convective precipitation associated with tropical depression (TD) is one primary type of post-flooding season rainfall in South China (SC). Observations of the Tropical Rainfall Measuring Mission (TRMM) satellite have shown specific diurnal features of convective rainfall in South China, which is somewhat different from that in other seasons or regions of China. Convective precipitation is usually organized into a rainfall band along the southeastern coast of South China in the early morning hours. The rainfall band develops and intensifies quickly in the morning, then moves inland in the afternoon and, finally, diminishes at night. The daily convective rainfall along the coast is much more than that in the inland region, and heavy rainfall is often found along the coast. A long-duration heavy rainfall event associated with tropical depression "Fitow" during the period from 28 August to 6 September 2001, is selected in this study to explore the diurnal feature of convective rainfall and its formation mechanism. Modeling results of the 10-day heavy rainfall event are compared with both rain-gauge observation and satellite-retrieved rainfall. Total precipitation and its spatial distribution, as well as diurnal variations are reasonably simulated and agree well with observations. Further analysis reveals that the development and movement of convective precipitation is mainly related to the land and sea breezes. The anomalous height-latitudinal circulation in the morning-to-noon hours is completely reversed in the afternoon-to-late-evening hours, with the convective rainfall swinging back and forth, following its updraft branch. Sensitivity experiments show that the afternoon convective rainfall in the inland region of SC is caused by the diurnal variation of solar radiation forcing. The mountain range along the coast and the complex topography in the inland region of SC plays a critical role in the enhancement of diurnal convective rainfall everywhere. The formation of a heavy rainfall band along the OPEN ACCESSAtmosphere 2014, 5 17 southeastern coast of SC and the diurnal variation of the rainfall pattern are mainly the results of the land-sea thermal contrast.

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“…Thus, the convective processes over the South China Sea would not be expected to be related to the TC formation process. Indeed, the diurnal evolution of convection throughout the morning and afternoon appears to correspond with the climatological diurnal variation of rainfall during a WWB as in Ho et al (2008). In the morning (0000 UTC, 0800 LT in Fig.…”

Section: A Diurnal Evolution Of Mcss During Formation (24-27 Septembmentioning

confidence: 99%

“…When the strong large-scale southwesterlies are present over the South China Sea owing to the eastward movement of the MJO over the western North Pacific (section 4), the primary area in which most of the MCSs and heavy precipitation originate is upstream and over the Philippines (Hoyos and Webster 2007;Ho et al 2008;Park et al 2011). Based on an analysis of eight years of TRMM PR rain rates, Ho et al (2008) found out that the diurnal maximum of rainfall during the WWB period occurs in the late morning.…”

Section: A Diurnal Evolution Of Mcss During Formation (24-27 Septembmentioning

confidence: 99%

“…Based on an analysis of eight years of TRMM PR rain rates, Ho et al (2008) found out that the diurnal maximum of rainfall during the WWB period occurs in the late morning. This peak rainfall is attributed to an organized oceanic convective system that develops in a region of maximum low-level convergence upstream (west) of Philippines.…”

Section: A Diurnal Evolution Of Mcss During Formation (24-27 Septembmentioning

confidence: 99%

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Tropical Cyclone Mekkhala’s (2008) Formation over the South China Sea: Mesoscale, Synoptic-Scale, and Large-Scale Contributions

Park

Kim

et al. 2015

Monthly Weather Review

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Tropical cyclone formation close to the coastline of the Asian continent presents a significant threat to heavily populated coastal countries. A case study of Tropical Storm Mekkhala (2008) that developed off the coast of Vietnam is presented using the high-resolution analyses of the European Centre for MediumRange Weather Forecasts/Year of Tropical Convection and multiple satellite observations. The authors have analyzed contributions to the formation from large-scale intraseasonal variability, synoptic perturbations, and mesoscale convective systems (MCSs). Within a large-scale westerly wind burst (WWB) associated with the Madden-Julian oscillation (MJO), synoptic perturbations generated by two preceding tropical cyclones initiated the pre-Mekkhala low-level vortex over the Philippine Sea. Typhoon Hagupit produced a synoptic-scale wave train that contributed to the development of Jangmi, but likely suppressed the Mekkhala formation. The low-level vortex of the pre-Mekkhala disturbance was then initiated in a confluent zone between northeasterlies in advance of Typhoon Jangmi and the WWB. A key contribution to the development of Mekkhala was from diurnally varying MCSs that were invigorated in the WWB. The oceanic MCSs, which typically develop off the west coast of the Philippines in the morning and dissipate in the afternoon, were prolonged beyond the regular diurnal cycle. A combination with the MCSs developing downstream of the Philippines led to the critical structure change of the oceanic convective cluster, which implies the critical role of mesoscale processes. Therefore, the diurnally varying mesoscale convective processes over both the ocean and land are shown to have an essential role in the formation of Mekkhala in conjunction with large-scale MJO and the synoptic-scale TC influences.

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Relationship between intraseasonal oscillation and diurnal variation of summer rainfall over the South China Sea

Cited by 21 publications

References 13 publications

The diurnal cycle of precipitation over the Maritime Continent in a high‐resolution atmospheric model

The diurnal cycle of precipitation over the Maritime Continent in a high‐resolution atmospheric model

Diurnal Variation of Rainfall Associated with Tropical Depression in South China and its Relationship to Land-Sea Contrast and Topography

Tropical Cyclone Mekkhala’s (2008) Formation over the South China Sea: Mesoscale, Synoptic-Scale, and Large-Scale Contributions

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