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
2021 ◽  
Vol 149 (10) ◽  
pp. 3449-3468
Author(s):  
Joshua Chun Kwang Lee ◽  
Anurag Dipankar ◽  
Xiang-Yu Huang

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.


2022 ◽  
Author(s):  
Haochen Tan ◽  
Pallav Ray ◽  
Bradford Barrett ◽  
Jimy Dudhia ◽  
Mitchell Moncrieff ◽  
...  

2010 ◽  
Vol 138 (4) ◽  
pp. 1474-1486 ◽  
Author(s):  
Mikiko Fujita ◽  
Fujio Kimura ◽  
Masanori Yoshizaki

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.


2009 ◽  
Vol 87A ◽  
pp. 413-424 ◽  
Author(s):  
Masayuki HARA ◽  
Takao YOSHIKANE ◽  
Hiroshi G. TAKAHASHI ◽  
Fujio KIMURA ◽  
Akira NODA ◽  
...  

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