Understanding the role of topography on the diurnal cycle of precipitation in the Maritime Continent during MJO propagation

2022 ◽  
Author(s):  
Haochen Tan ◽  
Pallav Ray ◽  
Bradford Barrett ◽  
Jimy Dudhia ◽  
Mitchell Moncrieff ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Maritime Continent ◽  
Diurnal Cycle Of Precipitation

scholarly journals On the Sensitivity of the Simulated Diurnal Cycle of Precipitation to 3-Hourly Radiosonde Assimilation: A Case Study over the Western Maritime Continent

2021 ◽  
Vol 149 (10) ◽  
pp. 3449-3468
Author(s):  
Joshua Chun Kwang Lee ◽  
Anurag Dipankar ◽  
Xiang-Yu Huang
Keyword(s):  
Diurnal Cycle ◽  
High Frequency ◽  
Initial Conditions ◽  
Rainfall Variability ◽  
Weather Prediction ◽  
Radiosonde Data ◽  
Western Coast ◽  
Maritime Continent ◽  
Model Biases ◽  
Diurnal Cycle Of Precipitation

AbstractThe diurnal cycle is the most prominent mode of rainfall variability in the tropics, governed mainly by the strong solar heating and land–sea interactions that trigger convection. Over the western Maritime Continent, complex orographic and coastal effects can also play an important role. Weather and climate models often struggle to represent these physical processes, resulting in substantial model biases in simulations over the region. For numerical weather prediction, these biases manifest themselves in the initial conditions, leading to phase and amplitude errors in the diurnal cycle of precipitation. Using a tropical convective-scale data assimilation system, we assimilate 3-hourly radiosonde data from the pilot field campaign of the Years of Maritime Continent, in addition to existing available observations, to diagnose the model biases and assess the relative impacts of the additional wind, temperature, and moisture information on the simulated diurnal cycle of precipitation over the western coast of Sumatra. We show how assimilating such high-frequency in situ observations can improve the simulated diurnal cycle, verified against satellite-derived precipitation, radar-derived precipitation, and rain gauge data. The improvements are due to a better representation of the sea breeze and increased available moisture in the lowest 4 km prior to peak convection. Assimilating wind information alone was sufficient to improve the simulations. We also highlight how during the assimilation, certain multivariate background error constraints and moisture addition in an ad hoc manner can negatively impact the simulations. Other approaches should be explored to better exploit information from such high-frequency observations over this region.

scholarly journals Morning Precipitation Peak over the Strait of Malacca under a Calm Condition

2010 ◽  
Vol 138 (4) ◽  
pp. 1474-1486 ◽  
Author(s):  
Mikiko Fujita ◽  
Fujio Kimura ◽  
Masanori Yoshizaki
Keyword(s):  
Numerical Model ◽  
Observational Data ◽  
Diurnal Cycle ◽  
Early Morning ◽  
Malay Peninsula ◽  
Maritime Continent ◽  
Precipitation System ◽  
Calm Condition ◽  
Diurnal Cycle Of Precipitation ◽  
Strait Of Malacca

Abstract This paper describes the formation mechanism of morning maximum in the diurnal cycle of precipitation, at the Strait of Malacca under a calm condition, with a nonhydrostatic mesoscale numerical model and ship-based observational data. The morning precipitation peak at the strait is induced by the convergence of two cold outflows that have been produced by the precipitation systems in the previous evening over Sumatra and the Malay Peninsula. The outflows converge at the Strait of Malacca around midnight; a new precipitation system is thus generated and reaches its peak in the early morning. Sensitivity experiments using the numerical model suggest that the timing and position of the morning precipitation peak are affected by the width of the strait. In the case of the Strait of Malacca, its width favors the formation of the morning precipitation system around the center of the strait, which explains why its diurnal cycle of precipitation can be observed much clearer than those in other coastal areas over the Maritime Continent.

scholarly journals Role of Diurnal Cycle in the Maritime Continent Barrier Effect on MJO Propagation in an AGCM

2021 ◽  
Vol 78 (5) ◽  
pp. 1545-1565
Author(s):  
R. S. Ajayamohan ◽  
Boualem Khouider ◽  
V. Praveen ◽  
Andrew J. Majda
Keyword(s):  
Diurnal Cycle ◽  
General Circulation ◽  
Dominant Role ◽  
Circulation Model ◽  
Striking Difference ◽  
Barrier Effect ◽  
Maritime Continent ◽  
Stochastic Case ◽  
The Impact

AbstractThe barrier effect of the Maritime Continent (MC) in stalling or modifying the propagation characteristics of the MJO is widely accepted. The strong diurnal cycle of convection over the MC is believed to play a dominant role in this regard. This hypothesis is studied here, with the help of a coarse-resolution atmospheric general circulation model (AGCM). The dry dynamical core of the AGCM is coupled to the multicloud parameterization piggybacked with a dynamical bulk boundary layer model. A set of sensitivity experiments is carried out by systematically varying the strength of the MC diurnal flux to assess the impact of the diurnal convective variability on the MJO propagation. The effects of deterministic and stochastic diurnal forcings on MJO characteristics are compared. It is found that the precipitation and zonal wind variance, on the intraseasonal time scales, over the western Pacific region decreases with the increase in diurnal forcing, indicating the blocking of MC precipitation. An increase in precipitation variance over the MC associated with the weakening of precipitation variance over the west Pacific is evident in all experiments. The striking difference between deterministic and stochastic diurnal forcing experiments is that the strength needed for the deterministic case to achieve the same degree of blocking is almost double that of stochastic case. The stochastic diurnal flux over the MC seems to be more detrimental in blocking the MJO propagation. This hints at the notion that the models with inadequate representation of organized convection tend to suffer from the MC-barrier effect.

scholarly journals Contemporary GCM Fidelity in Representing the Diurnal Cycle of Precipitation Over the Maritime Continent

2019 ◽  
Vol 124 (2) ◽  
pp. 747-769 ◽  
Author(s):  
Dariusz B. Baranowski ◽  
Duane E. Waliser ◽  
Xianan Jiang ◽  
James A. Ridout ◽  
Maria K. Flatau
Keyword(s):  
Diurnal Cycle ◽  
Maritime Continent ◽  
Diurnal Cycle Of Precipitation

Possible Role of the Diurnal Cycle in Land Convection in the Barrier Effect on the MJO by the Maritime Continent

2019 ◽  
Vol 46 (5) ◽  
pp. 3001-3011 ◽  
Author(s):  
Jian Ling ◽  
Chidong Zhang ◽  
Robert Joyce ◽  
Ping‐ping Xie ◽  
Guiwan Chen
Keyword(s):  
Diurnal Cycle ◽  
Barrier Effect ◽  
Maritime Continent

scholarly journals Assessment of the Diurnal Cycle of Precipitation over the Maritime Continent Simulated by a 20 km Mesh GCM Using TRMM PR Data

2009 ◽  
Vol 87A ◽  
pp. 413-424 ◽  
Author(s):  
Masayuki HARA ◽  
Takao YOSHIKANE ◽  
Hiroshi G. TAKAHASHI ◽  
Fujio KIMURA ◽  
Akira NODA ◽  
...  
Keyword(s):  
Diurnal Cycle ◽  
Maritime Continent ◽  
Trmm Pr ◽  
Diurnal Cycle Of Precipitation
Sign in / Sign up

Export Citation Format

Share Document