scholarly journals Comparisons of Low-Level Circulation Characteristics between ECHAM5/MPI-OM Results and NCEP/NCAR Re-Analysis Data in East Asia

2010 ◽  
Vol 3 (4) ◽  
pp. 189-194 ◽  
Author(s):  
Zhao De-Ming ◽  
Fu Cong-Bin
Keyword(s):  
East Asia ◽  
Analysis Data ◽  
Low Level ◽  
Circulation Characteristics

scholarly journals Variation of High and Low Level Circulation of Meiyu in Jiangsu Province in Recent 30 Years

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1258
Author(s):  
Ruoxin Hu ◽  
Lijuan Wang
Keyword(s):  
Western Pacific Subtropical High ◽  
Analysis Data ◽  
Jiangsu Province ◽  
Water Vapor Transport ◽  
Low Level ◽  
South Asia High ◽  
Westerly Jet ◽  
Daily Precipitation Data ◽  
The Western Pacific ◽  
Circulation Characteristics

By using the NCEP/NCAR re-analysis data from 1990 to 2019 and the daily precipitation data of CN05.1 gridded observation dataset, the high and low level circulation characteristics and their influence on the onset and precipitation of Meiyu in Jiangsu Province in recent 30 years are studied. Comparing Meiyu in the 2010s with that in the 1990s, it is found that during the 2010s Meiyu was characterized by a late arrival and less precipitation. There were obviously earlier Meiyu years in the 1990s, while no extremely early Meiyu year existed in the 2010s, which was mainly caused by the late northward jump of the upper jet and the ridge line of the western Pacific subtropical high (WPSH hereinafter) in the 2010s. Compared with the 1990s, the 2010s witnessed an eastward position of the South Asia high and a westward position of the subtropical westerly jet during the Meiyu period, which are not conducive to precipitation in the Yangtze-Huaihe region. At the same time, the cold air flowing southward to the Yangtze-Huaihe region was hindered in the 2010s due to the change of blocking in the middle troposphere. In the 2010s, the water vapor transport and the vertical transportation weakened, resulting in the decrease of precipitation in the Yangtze-Huaihe region.

Parameter Tuning and Calibration of RegCM3 with MIT–Emanuel Cumulus Parameterization Scheme over CORDEX East Asia Domain

2014 ◽  
Vol 27 (20) ◽  
pp. 7687-7701 ◽  
Author(s):  
Liwei Zou ◽  
Yun Qian ◽  
Tianjun Zhou ◽  
Ben Yang
Keyword(s):  
East Asia ◽  
Regional Climate ◽  
Cumulus Parameterization ◽  
Parameterization Scheme ◽  
Cumulus Parameterization Scheme ◽  
Convection Scheme ◽  
Total Rainfall ◽  
Low Level ◽  
Positive Effects ◽  
Cordex East Asia

Abstract In this study, the authors calibrated the performance of the Regional Climate Model, version 3 (RegCM3), with the Massachusetts Institute of Technology (MIT)–Emanuel cumulus parameterization scheme over the Coordinated Regional Climate Downscaling Experiment (CORDEX) East Asia domain by tuning seven selected parameters based on the multiple very fast simulated annealing (MVFSA) approach. The seven parameters were selected based on previous studies using RegCM3 with the MIT–Emanuel convection scheme. The results show the simulated spatial pattern of rainfall, and the probability density function distribution of daily rainfall rates is significantly improved in the optimal simulation. Sensitivity analysis suggests that the parameter relative humidity criteria (RHC) has the largest effect on the model results. Followed by an increase of RHC, an increase of total rainfall is found over the northern equatorial western Pacific, mainly contributed by the increase of explicit rainfall. The increases of the convergence of low-level water vapor transport and the associated increases in cloud water favor the increase of explicit rainfall. The identified optimal parameters constrained by total rainfall have positive effects on the low-level circulation and surface air temperature. Furthermore, the optimized parameters based on the chosen extreme case are transferable to a normal case and the model’s new version with a mixed convection scheme.

scholarly journals Pembelajaran Bahasa Arab di Provinsi Lampung Tahun 2016

2017 ◽  
Vol 1 (01) ◽  
pp. 1
Author(s):  
Akla Akla
Keyword(s):  
High School ◽  
Language Learning ◽  
Learning Process ◽  
Language Skills ◽  
Analysis Data ◽  
Arabic Language ◽  
Survey Study ◽  
Low Level ◽  
Medium Level ◽  
Associative Analysis

This research aims to reveal the data of Arabic language learning in Lampung. This research is focused on teachers professionality, Arabic learning process, and  students’ Arabic language skills that consist of istima’, kalam, qira’ah, and kitabah. This research refers to a survey study by collecting information from sample through questionnaire. The objectives of this research not only examine the map of teachers professionality, Arabic learning process, and students’ Arabic language skills but also find out the interaction between learning process and students’ Arabic skills. The samples of this research were 49 Arabic teachers and 382 students of Islamic Senior High School around Lampung. From the results of analysis data, it can be concluded that teachers professionality belongs to medium level, Arabic learning process belongs to medium level, students’ Arabic language skills belong to low level. The results of associative analysis showed that there is a significant influence between learning process and students’ Arabic language skills; therefore, it can be regarded that un-maximal learning process and environment have an impact towards the students low-level Arabic language skills.

The role of surface air temperature over the east Asia on the early and late Indian Summer Monsoon Onset over Kerala

2020 ◽  
Author(s):  
Devanil Choudhury ◽  
Debashis Nath ◽  
Wen Chen
Keyword(s):  
East Asia ◽  
Air Temperature ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Late Onset ◽  
Southern China ◽  
Surface Air Temperature ◽  
Monsoon Onset ◽  
Low Level ◽  
Summer Monsoon Onset

<p>We investigated the physical mechanism for late Indian Summer Monsoon onset over Kerala<br>(MOK). 14 early and 9 late onset years are selected based on the criteria when the onset is 5 days or<br>more prior and after normal onset date (i.e 1 st June according to India Meteorological Department)<br>respectively. Then, we perform composite analyses of mean May monthly and daily evolution during<br>early and late onset years to examine the differences in monsoon circulation features prior to the MOK.<br>We find that advection of Surface Air Temperature (SAT) from the northern to the southern China and<br>the eastern Tibetan Plateau (TP) plays an important role to modulate the MOK processes. In the late<br>onset years, more low-level jet (LLJ) from the Bay of Bengal (BOB) divert towards the east Asia before<br>the onset, which is due to an extension of the low sea level pressure and high SAT over the east Asia<br>(eastern TP, east-central China). This strengthens the low-level convergence and upper level divergence<br>over the eastern TP and southern China. As a result, a significant amount of moisture from the BOB<br>is transported towards the eastern TP and southern China. Thereby, a comparatively weaker LLJ and<br>deficit low-level moisture supply over the eastern BOB maintain the key roles in modulating the MOK<br>processes.</p>

scholarly journals Diurnal Cycle of a Heavy Rainfall Corridor over East Asia

2017 ◽  
Vol 145 (8) ◽  
pp. 3365-3389 ◽  
Author(s):  
Guixing Chen ◽  
Weiming Sha ◽  
Toshiki Iwasaki ◽  
Zhiping Wen
Keyword(s):  
East Asia ◽  
Heavy Rainfall ◽  
Southern China ◽  
Central China ◽  
Moist Convection ◽  
Low Level ◽  
Effective Discharge ◽  
Upward Transport ◽  
Convection Initiation ◽  
The Impact

Moist convection occurred repeatedly in the midnight-to-morning hours of 11–16 June 1998 and yielded excessive rainfall in a narrow latitudinal corridor over East Asia, causing severe flood. Numerical experiments and composite analyses of a 5-day period are performed to examine the mechanisms governing nocturnal convection. Both simulations and observations show that a train of MCSs concurrently developed along a quasi-stationary mei-yu front and coincided with the impact of a monsoon surge on a frontogenetic zone at night. This process was regulated primarily by a nocturnal low-level jet (NLLJ) in the southwesterly monsoon that formed over southern China and extended to central China. In particular, the NLLJ acted as a mechanism of moisture transport over the plains. At its northern terminus, the NLLJ led to a zonal band of elevated conditionally unstable air where strong low-level ascent overcame small convective inhibition, triggering new convection in three preferred plains. An analysis of convective instability shows that the low-tropospheric intrusion of moist monsoon air generated CAPE of ~1000 J kg−1 prior to convection initiation, whereas free-atmospheric forcing was much weaker. The NLLJ-related horizontal advection accounted for most of the instability precondition at 100–175 J kg−1 h−1. At the convective stage, instability generation by the upward transport of moisture increased to ~100 J kg−1 h−1, suggesting that ascending inflow caused feedback in convection growth. The convection dissipated in late morning with decaying NLLJ and moisture at elevated layers. It is concluded that the diurnally varying summer monsoon acted as an effective discharge of available moist energy from southern to central China, generating the morning-peak heavy rainfall corridor.

scholarly journals Unprecedented Temporary Reduction in Global Air Pollution Associated with COVID-19 Forced Confinement: A Continental and City Scale Analysis

2020 ◽  
Vol 12 (15) ◽  
pp. 2420 ◽  
Author(s):  
Zhijie Zhang ◽  
Arfan Arshad ◽  
Chuanrong Zhang ◽  
Saddam Hussain ◽  
Weidong Li
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
East Asia ◽  
Anthropogenic Activities ◽  
Analysis Data ◽  
Baseline Period ◽  
Scale Analysis ◽  
Ozone Monitoring Instrument ◽  
Continental Scale ◽  
Maximum Reduction

Shortly after the outbreak of the novel infectious disease (COVID-19) started at the end of 2019, it turned into a global pandemic, which caused the lockdown of many countries across the world. Various strict measures were adopted to reduce anthropogenic activities in order to prevent further spread and infection of the disease. In this study, we utilized continental scale remotely sensed data along with city scale in situ air quality observations for 2020 as well as data from the baseline period (2015–2019) to provide an early insight on air pollution changes in response to the COVID-19 pandemic lockdown, by combining both continental and city scales. For the continental scale analysis, data of NO2, SO2, and O3 were acquired from the ozone monitoring instrument (OMI) and data of aerosol optical depth (AOD) were collected from the moderate resolution imaging spectroradiometer (MODIS). For city scale analysis, data of NO2, CO, PM2.5, O3, and SO2 were derived from ground-based air quality observations. Results from satellite observations at the continental scale showed that concentrations of NO2, SO2, and AOD substantially dropped in 2020 during the lockdown period compared to their averages for the baseline period over all continents, with a maximum reduction of ~33% for NO2 in East Asia, ~41% for SO2 in East Asia, and ~37% for AOD in South Asia. In the case of O3, the maximum overall reduction was observed as ~11% in Europe, followed by ~10% in North America, while a slight increase was found in other study regions. These findings align with ground-based air quality observations, which showed that pollutants such as NO2, CO, PM2.5, and SO2 during the 2020 lockdown period decreased significantly except that O3 had varying patterns in different cities. Specifically, a maximum reduction of ~49% in NO2 was found in London, ~43% in CO in Wuhan, ~38% in PM2.5 in Chennai, and ~48% in SO2 in Beijing. In the case of urban O3, a maximum reduction of ~43% was found in Wuhan, but a significant increase of ~47% was observed in Chennai. It is obvious that restricted human activities during the lockdown have reduced the anthropogenic emissions and subsequently improved air quality, especially across the metropolitan cities.

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