Impacts of Cloud Microphysics Modifications on Diurnal Convection and the ISO over the Maritime Continent: A Case Study of YMC-Sumatra 2017

Nasuno, Tomoe

doi:10.2151/sola.2021-003

Cited by 3 publications

(4 citation statements)

References 45 publications

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“…For the MJO run, this feature is not confirmed, and the total number of convective cores is ∼20% smaller (Figure 2e). These results, as well as those shown in Figure 2c, confirm that the HighResMIP-tuned setting favors strong deep convection more than the MJO-tuned setting, as implied by Nasuno (2021). The above differences in the two runs are related to the different relationship between individual deep convection and moisture accumulation and detrainment.…”

Section: Deep Convection Characteristicssupporting

confidence: 75%

“…The degree of this late precipitation onset is different among the sensitivity experiments: the onset (with precipitation more than 10.5 mm day 1 ) is most delayed in the MJO run (19:00 LT; Figure 21c), and closest to the observation in the MP-LEO2-L78 run (17:00 LT; Figure 21e). A tendency similar to that in the MJO run was also confirmed in Nasuno (2021), who examined the 7-km mesh simulation of diurnal convection in the Maritime Continent. The better performance in the MP-LEO2-L78 run is probably because more vertical layers in the PBL can improve the representation of convection triggering.…”

Section: Tropical Precipitation Diurnal Cyclesupporting

confidence: 65%

“…In fact, Miura (2019) showed that the MJO reproducibility in GCRMs is sensitive to cloud microphysics parameters, such as the velocity of falling rain and snow, that can affect the vertical profile of moisture and clouds. The impacts of microphysics are also confirmed in the TC development (Nasuno et al, 2016) and diurnal convection over the Maritime Continent (Nasuno, 2021). In addition, the choice and parameter settings of turbulent schemes can influence the favored spatio-temporal scale of convective organization by changing the efficiency of the subgrid-scale horizontal/upward moisture transport (Holloway et al, 2013;Miura, Satoh, Tomita, et al, 2007).…”

Section: Introductionmentioning

confidence: 85%

“…Also, the MJO run allows stronger and continuous mid-to-upper tropospheric moistening maximized in 600-500 hPa after t = 0 hr, in conjunction with stronger PBL drying, which is partly due to active moisture transport to the free troposphere. These behaviors are certainly favorable for good MJO simulations (e.g., Hannah & Maloney, 2011;Hirons et al, 2013;Klingaman & Woolnough, 2014;Nasuno, 2021).…”

Section: Journal Of Advances In Modeling Earth Systemsmentioning

confidence: 98%

See 3 more Smart Citations

How Can We Improve the Seamless Representation of Climatological Statistics and Weather Toward Reliable Global K‐Scale Climate Simulations?

Takasuka,

Kodama,

Suematsu

et al. 2024

J Adv Model Earth Syst

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Toward the achievement of reliable global kilometer‐scale (k‐scale) climate simulations, we improve the Nonhydrostatic ICosahedral Atmospheric Model (NICAM) by focusing on moist physical processes. A goal of the model improvement is to establish a configuration that can simulate realistic fields seamlessly from the daily‐scale variability to the climatological statistics. Referring to the two representative configurations of the present NICAM, each of which has been used for climate‐scale and sub‐seasonal‐scale experiments, we try to find the appropriate partitioning of fast/local and slow/global‐scale circulations. In a series of sensitivity experiments at 14‐km horizontal resolution, we test (a) the tuning of terminal velocities of rain, snow, and cloud ice, (b) the implementation of turbulent diffusion by the Leonard term, and (c) enhanced vertical resolution. These tests yield reasonable convection triggering and convection‐induced tropospheric moistening, and result in better performance than in previous NICAM climate simulations. In the mean state, double Intertropical Convergence Zone bias disappears, and the zonal contrast of equatorial precipitation, top‐of‐atmosphere radiation balance, vertical temperature profile, and position/strength of subtropical jet are reproduced dramatically better. Variability such as equatorial waves and the Madden–Julian oscillation (MJO) is spontaneously realized with appropriate spectral power balance, and the Asian summer monsoon, boreal‐summer MJO, and tropical cyclone (TC) activities are more realistically simulated especially around the western Pacific. Meanwhile, biases still exist in the representation of low‐cloud fraction, TC intensity, and precipitation diurnal cycle, suggesting that both higher spatial resolutions and further model development are warranted.

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Section: Deep Convection Characteristicssupporting

confidence: 75%

Section: Tropical Precipitation Diurnal Cyclesupporting

confidence: 65%

Section: Introductionmentioning

confidence: 85%

Section: Journal Of Advances In Modeling Earth Systemsmentioning

confidence: 98%

See 2 more Smart Citations

How Can We Improve the Seamless Representation of Climatological Statistics and Weather Toward Reliable Global K‐Scale Climate Simulations?

Takasuka,

Kodama,

Suematsu

et al. 2024

J Adv Model Earth Syst

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Why Does Convection Weaken over Sumatra Island in an Active Phase of the MJO?

Zhao

Yokoi

et al. 2022

Monthly Weather Review

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This study investigated the diurnal cycle of convection over Sumatra Island in an active phase of the Madden-Julian Oscillation (MJO) during the Pre-Years of the Maritime Continent (YMC) observation campaign in December 2015 based on in-situ and satellite observations and a convection-permitting numerical model. Observations suggest that before the active phase of the MJO in early December, convection occurred frequently over the island during the afternoon and at midnight. By contrast, during the active phase of the MJO in mid-December, afternoon convection over the island was delayed and suppressed, and midnight convection was suppressed. Numerical experiments also successfully replicated the main features of the observed modulations. In general, during the active phase of the MJO, the troposphere became drier in the Sumatra region. While the clouds reduced the solar radiation over the land, the sea breeze was also found to be delayed and weakened. As a result, the afternoon convection initiation was delayed and weakened. Further analyses suggested that the sea breeze was weakened mainly due to the orographic stagnation effect rather than the slightly reduced land-sea temperature contrast. On the other hand, the increased stratiform-anvil clouds induced the anomalous evaporative cooling in the mid-troposphere and generated island-scale subsidence during the nighttime, which finally led to the suppression of inland convection. Overall, our study reveals the modulation of diurnal convection over Sumatra Island by an active phase of the MJO and also shows the potential role of land-sea interaction in convection initiation and maintenance.

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Precipitation Diurnal Cycle over Tropical Coastal Regions Represented in Climate Experiments with a Global Cloud-System Resolving Model

Yokoi,

Kajikawa

2024

SOLA

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Climate experiments using global cloud-system resolving models (GCRMs) are expected to realistically simulate precipitation diurnal cycle (PDC) in the tropics, which is important for better representation of influences of cumulus convection on the climate system. This study examines how three series of decade-long climate experiments with Nonhydrostatic ICosahedral Atmospheric Model (NICAM), one of the GCRMs, realistically simulate the PDC over tropical coastal regions. Analyses reveal that it is more difficult to reproduce the PDC over coastal waters than that over coastal land, the former of which is characterized by nighttime offshore migration of precipitation areas. A Yokoi and Kajikawa, Precipitation diurnal cycle in climate experiments with a GCRM 2 comparison with in situ shipborne observations further reveals that biases in the offshore migration feature are associated with poor representation of convective cold pools; experiments with poor reproducibility of the offshore migration underestimate overall intensity of cold pools. The underestimation of the intensity may be associated with overestimation of environmental moisture in the lower free troposphere. As reproducing the environmental field is a difficult task particularly for climate experiments with global models, it seems more challenging for the climate experiments to realistically simulate the PDC over the coastal waters than for short-term experiments and regional climate experiments. (Yokoi, S., and Y. Kajikawa, 2024: Precipitation diurnal cycle over tropical coastal regions represented in climate experiments with a global cloud-system resolving model.

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Impacts of Cloud Microphysics Modifications on Diurnal Convection and the ISO over the Maritime Continent: A Case Study of YMC-Sumatra 2017

Cited by 3 publications

References 45 publications

How Can We Improve the Seamless Representation of Climatological Statistics and Weather Toward Reliable Global K‐Scale Climate Simulations?

How Can We Improve the Seamless Representation of Climatological Statistics and Weather Toward Reliable Global K‐Scale Climate Simulations?

Why Does Convection Weaken over Sumatra Island in an Active Phase of the MJO?

Precipitation Diurnal Cycle over Tropical Coastal Regions Represented in Climate Experiments with a Global Cloud-System Resolving Model

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