The Behaviors of Intraseasonal Cloud Organization During DYNAMO/AMIE

Sakaeda, Naoko; Torri, Giuseppe

doi:10.1029/2021jd035749

Cited by 5 publications

(24 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The varying strength of MCS modulation among CCEWs suggests that not all waves provide equally favorable environments for MCS growth. This is likely rooted in differing moist dynamics between CCEWs (Adames, 2022; Nakamura & Takayabu, 2022b; Sakaeda & Torri, 2022; Wolding et al., 2020; Yasunaga & Mapes, 2011). CCEWs such as the MJO and ER are primarily driven by moisture variability.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Mesoscale Convective Systems Modulated by Convectively Coupled Equatorial Waves

Cheng

Dias

Kiladis

et al. 2023

Geophysical Research Letters

View full text Add to dashboard Cite

Satellite observations of clouds in the tropics reveal a hierarchy of organized cloud clusters ranging from the planetary-scale Madden-Julian Oscillation (MJO), through synoptic-scale convectively coupled equatorial waves (CCEWs), to mesoscale convective systems (MCSs, S. S. Chen et al., 1996;Mapes & Houze, 1993;Nakazawa, 1988). These various types of convective organization are not necessarily independent from one another, and MCSs, with scales of 100s of kilometers, are often considered building blocks of those larger-scale tropical circulations (Mapes et al., 2006). The most intense MCSs often cause high-impact weather events. The frequency of these rainfall extremes has increased in the past few decades and is projected to rise with climate change (Z. Feng et al., 2016;Tabari, 2020;Taylor et al., 2017). While MCSs are difficult to predict in current global weather and climate models due to their smaller scales and dependence on subgrid-scale processes, larger-scale disturbances such as CCEWs can be predicted with higher skill beyond 1 week (

show abstract

Section: Conclusion and Discussionmentioning

confidence: 99%

Mesoscale Convective Systems Modulated by Convectively Coupled Equatorial Waves

Cheng

Dias

Kiladis

et al. 2023

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…These results allow us to infer the role of cold pools on cloud organization associated with the different phases of the MJO that is documented in Sakaeda and Torri (2022). Their study finds that the number of deep convective cells maximizes during the MJO growing-to-enhanced phase, contributing to the maximum rainfall shown in Figures 3a and 3b.…”

Section: Spatio-temporal Evolution Of Rainfall Relative To Cold Poolsmentioning

confidence: 71%

“…During the growing-to-enhanced phase of the MJO, when the environmental moisture is at its peak, there is a greater number of deep convective cells, but their occurrence may be less associated with cold pools. Sakaeda and Torri (2022) speculated that the high environmental moisture allows convection to form more randomly due to the favorable environment for convection to develop and sustain. This does not mean that cold pools are less effective at generating convection during the growing-to-enhanced phase of the MJO.…”

Section: Spatio-temporal Evolution Of Rainfall Relative To Cold Poolsmentioning

confidence: 99%

“…Figure 2a shows the evolution of MJO convection around Addu Atoll and the Revelle on this local MJO phase diagram. The local phase angles are defined in the same manner as Sakaeda and Torri (2022), where 0° indicates the center of the enhanced MJO convective envelope, and ±180° is the center of the suppressed convective envelope. A negative phase angle around −90° represents the developing state of enhanced convection (ahead or east of enhanced convection), and a positive phase angle around 90° represents its decaying state (behind or west of enhanced convection).…”

Section: Identification Of Mjo Phasementioning

confidence: 99%

See 1 more Smart Citation

The Observed Effects of Cold Pools on Convection Triggering and Organization During DYNAMO/AMIE

Sakaeda

Torri

2023

JGR Atmospheres

Self Cite

View full text Add to dashboard Cite

Cold pools that form from existing convection can generate new clouds nearby, a process that has been suggested to contribute to cloud organization. However, some disagreement exists on the role of cold pools in cloud organization over tropical oceans, and much remains to be understood on how this role depends on the state of large‐scale disturbances such as the Madden‐Julian Oscillation (MJO). This study addresses this question by examining the intraseasonal variability in the properties of cold pools and their effects on convection triggering using observations. The unique set of surface meteorology data and ground‐based radars deployed during the DYNAMO/AMIE field campaign are used to identify cold pools and the associated spatiotemporal evolution of rainfall. The results suggest that cold pools enhance rainfall at their expected speed of 3–8 m s−1, which includes the Doppler‐shifting effect by the background wind. The cold pools also enhance rainfall mainly within a 20 km radius, especially in the direction of boundary‐layer vertical wind shear. However, gravity waves appear to contribute predominantly to the propagation of convection over a wider range of distances due to their faster propagation speeds. The interface of convection triggering and propagation at different speeds of cold pools and gravity waves seems to contribute to cloud organization. The effectiveness of cold pools and gravity waves on cloud organization also depends highly on the MJO due to the combined effects of changes in environmental humidity and boundary to lower‐tropospheric wind.

show abstract

“…This sensitivity might also be relevant to analyze observations. In particular, it might explain why the spatial organization of convection vary with the intraseasonal or seasonal variability; for example, it might explain why convection is more organized in the decaying phase of the MJO than in the active phase (Sakaeda & Torri, 2022).…”

Section: Discussionmentioning

confidence: 99%

Sensitivity of Convective Self‐Aggregation to Subsidence

Bellon

Coppin

2022

J Adv Model Earth Syst

View full text Add to dashboard Cite

Simulations using the convection-permitting MesoNH model with imposed vertical motion document the influence of large-scale circulation on convective self-aggregation. Results show that subsidence favors self-aggregation in this model and that this sensitivity includes a hysteresis: for weak subsidence, only one stationary state is found, without aggregation; for moderate subsidence, two stationary states are found, one with aggregation and one without; for large subsidence, only the aggregated stationary state is found. In that state, the area covered by deep convection decreases with subsidence. Using the variance of column moist static energy (MSE) as a metric for aggregation, we detail the role of physical processes in the development or maintenance of aggregation.Solar radiation always contributes positively to aggregation. The effect of terrestrial radiation results from a competition between the effects of the top-of-atmosphere and surface fluxes, and can therefore vary in amplitude and change sign both with time in transient simulations and with subsidence intensity in stationary state. The effect of turbulent surface fluxes also result from a competition between the effect of air-sea thermodynamic contrast and the wind-induced contribution, and it can also vary very significantly. The contribution of MSE transport within the model domain also changes from negative to positive as the intensity of subsidence is increased because the shallow circulation accelerates and causes a change of sign in the gross moist stability associated with this circulation.

show abstract

The Behaviors of Intraseasonal Cloud Organization During DYNAMO/AMIE

Cited by 5 publications

References 69 publications

Mesoscale Convective Systems Modulated by Convectively Coupled Equatorial Waves

Mesoscale Convective Systems Modulated by Convectively Coupled Equatorial Waves

The Observed Effects of Cold Pools on Convection Triggering and Organization During DYNAMO/AMIE

Sensitivity of Convective Self‐Aggregation to Subsidence

Contact Info

Product

Resources

About