scholarly journals The diurnal cycle of precipitation over the Maritime Continent in a high-resolution atmospheric model

2011 ◽  
Vol 137 (657) ◽  
pp. 934-947 ◽  
Author(s):  
Barnaby S. Love ◽  
Adrian J. Matthews ◽  
Grenville M. S. Lister
Keyword(s):  
High Resolution ◽  
Diurnal Cycle ◽  
Atmospheric Model ◽  
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 Multimodel Prediction Skills of the Somali and Maritime Continent Cross-Equatorial Flows

2018 ◽  
Vol 31 (6) ◽  
pp. 2445-2464 ◽  
Author(s):  
Chen Li ◽  
Jing-Jia Luo ◽  
Shuanglin Li ◽  
Harry Hendon ◽  
Oscar Alves ◽  
...  
Keyword(s):  
High Resolution ◽  
Walker Circulation ◽  
Seasonal Prediction ◽  
Atmospheric Model ◽  
Precipitation Anomaly ◽  
Boreal Summer ◽  
Maritime Continent ◽  
Anomaly Correlation Coefficient ◽  
The Difference ◽  
The Individual

Predictive skills of the Somali cross-equatorial flow (CEF) and the Maritime Continent (MC) CEF during boreal summer are assessed using three ensemble seasonal forecasting systems, including the coarse-resolution Predictive Ocean Atmospheric Model for Australia (POAMA, version 2), the intermediate-resolution Scale Interaction Experiment–Frontier Research Center for Global Change (SINTEX-F), and the high-resolution seasonal prediction version of the Australian Community Climate and Earth System Simulator (ACCESS-S1) model. Retrospective prediction results suggest that prediction of the Somali CEF is more challenging than that of the MC CEF. While both the individual models and the multimodel ensemble (MME) mean show useful skill (with the anomaly correlation coefficient being above 0.5) in predicting the MC CEF up to 5-month lead, only ACCESS-S1 and the MME can skillfully predict the Somali CEF up to 2-month lead. Encouragingly, the CEF seesaw index (defined as the difference of the two CEFs as a measure of the negative phase relation between them) can be skillfully predicted up to 4–5 months ahead by SINTEX-F, ACCESS-S1, and the MME. Among the three models, the high-resolution ACCESS-S1 model generally shows the highest skill in predicting the individual CEFs, the CEF seesaw, as well as the CEF seesaw index–related precipitation anomaly pattern in Asia and northern Australia. Consistent with the strong influence of ENSO on the CEFs, the skill in predicting the CEFs depends on the model’s ability in predicting not only the eastern Pacific SST anomaly but also the anomalous Walker circulation that brings ENSO’s influence to bear on the CEFs.

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 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 Understanding Biases in Simulating the Diurnal Cycle of Convection over the Western Coast of Sumatra: Comparison with Pre-YMC Observation Campaign

2019 ◽  
Vol 147 (5) ◽  
pp. 1615-1631 ◽  
Author(s):  
Anurag Dipankar ◽  
Stuart Webster ◽  
Xiang-Yu Huang ◽  
Van Quang Doan
Keyword(s):  
High Resolution ◽  
Diurnal Cycle ◽  
Local Convergence ◽  
Land Breeze ◽  
Limited Area ◽  
Western Coast ◽  
Initial Condition ◽  
Maritime Continent ◽  
Total Delay ◽  
Sst Bias

Abstract Biases in simulating the diurnal cycle of convection near the western coast of the island of Sumatra have been investigated using the data from the pilot field campaign of the Years of the Maritime Continent (pre-YMC). The campaign was carried out at a sea [Research Vessel (R/V) Mirai] and a land (Bengkulu, Sumatra) site. Simulations are performed using a tropical configuration of the Met Office model at a grid resolution of 1.5 km in a limited-area mode. The focus of this study is to understand how biases in the input conditions from ECMWF high-resolution deterministic forecast affect the diurnal cycle. Modeled precipitation is found to be delayed and weak, with cold SST bias in the model as the key contributing factor affecting convection at both sites. Colder SST causes a delay in the trigger of convection at Bengkulu by delaying the onset of the local land breeze, which in turn delays the local convergence. The cold outflow from precipitation over the adjacent mountain is also found to be delayed in the model, contributing to the total delay. This delay in the evening convection at Bengkulu is shown to directly affect the timing of nighttime convection at Mirai. Weaker convection at Bengkulu is argued to be due to lower-tropospheric dry humidity bias in the model initial condition. Convection at Mirai is shown to be caused by the convergence of the cold outflow from Bengkulu with the prevailing landward wind over the sea. Both thermodynamic and dynamic conditions near the cold outflow front are found to be less favorable for intense convection in the simulation, the reason for which is argued to be a combination of the cold SST bias and a weaker cold outflow.

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
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