scholarly journals Seasonal variation of black carbon over the South China Sea and in various continental locations in South China

2013 ◽  
Vol 13 (7) ◽  
pp. 17375-17405 ◽  
Author(s):  
D. Wu ◽  
C. Wu ◽  
B. Liao ◽  
F. Li ◽  
H. Tan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Rainy Season ◽  
Dry Season ◽  
The South China Sea ◽  
The South ◽  
Monsoon Period ◽  
China Sea ◽  
Background Site ◽  
Urban Sites

Abstract. Black carbon (BC) is an important atmospheric constitute as an air pollutant and as a climate forcer. To our knowledge, field measurements of BC have not been reported over the South China Sea. Observation of light absorption coefficients (σabs) and BC concentrations by Aethalometer were conducted on Yongxing Island in the South China Sea and at five continental sites in the Pearl River Delta (PRD) region, South China during the South China Sea monsoon period (rainy season, 16 May–20 June 2008) and the northeast monsoon period (dry season, 12 December 2008–8 January 2009). At the oceanic site, the daily average BC concentrations vary from 0.28 to 2.14 μg m−3 and seasonal variations of BC were small (0.67 in dry season and 0.54 μg m−3 in rainy season). Similarly, little seasonal difference was found at a background site in PRD (2.88 in dry season and 2.62 μg m−3 in rainy season). At PRD urban sites, the daily average concentration of BC ranges from 1.56 to 37.9 μg m−3, higher in the dry season (12.6 μg m−3) and lower in the rainy season (6.4 μg m−3). The observed average σabs values in rainy vs. dry seasons are 119 vs. 62 Mm−1 at the PRD urban sites, 29 vs. 26 Mm−1 at the PRD background site, and 8.4 vs. 7.2 Mm−1 at the marine site. A bi-peak pattern in diurnal BC variation was observed at all sites while this pattern is the most prominent at the urban sites. The first peak appears in the early morning rush hour and the second peak in early evening, with the evening peak more pronounced in dry season.

scholarly journals Black carbon over the South China Sea and in various continental locations in South China

2013 ◽  
Vol 13 (24) ◽  
pp. 12257-12270 ◽  
Author(s):  
D. Wu ◽  
C. Wu ◽  
B. Liao ◽  
H. Chen ◽  
M. Wu ◽  
...  
Keyword(s):  
South China Sea ◽  
Black Carbon ◽  
South China ◽  
Rainy Season ◽  
Sampling Period ◽  
Dry Season ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Urban Sites

Abstract. Black carbon (BC) is an important atmospheric constituent as an air pollutant and as a climate forcer. To our knowledge, field measurements of BC have not been reported over the South China Sea. Observations of light-absorption coefficients (σabs) and BC concentrations by Aethalometer were conducted on Yongxing Island in the South China Sea and at five continental sites in the Pearl River delta (PRD) region, South China, in two periods: 16 May–20 June 2008 in the rainy season and 12 December 2008–8 January 2009 in the dry season. At the oceanic site, the daily average BC concentrations varied from 0.28 to 2.14 μg m−3 and variations of BC were small between the two periods (0.67 in the dry season sampling period and 0.54 μg m−3 in the rainy season sampling period). Similarly, little difference in BC level was found at a rural site in PRD between the two sampling periods (2.88 and 2.62 μg m–3). At the PRD urban sites, the daily average concentration of BC ranged from 1.56 to 37.9 μg m−3, higher in the dry season sampling period (12.31 μg m–3) and lower in the rainy season sampling period (6.17 μg m–3). The observed average σabs values in rainy vs. dry season sampling periods are 119 vs. 62 Mm−1 at the PRD urban sites, 29 vs. 26 Mm−1 at the PRD background site, and 8.4 vs. 7.2 Mm−1 at the marine site. At urban/suburban PRD sites, BC was observed to have a diurnal pattern of higher concentrations at night and at the urban sites a small peak in the early morning rush hour.

Influence of mesoscale eddies on primary production in the South China Sea during spring inter-monsoon period

2014 ◽  
Vol 33 (3) ◽  
pp. 118-128 ◽  
Author(s):  
Zifeng Hu ◽  
Yehui Tan ◽  
Xingyu Song ◽  
Linbin Zhou ◽  
Xiping Lian ◽  
...  
Keyword(s):  
South China Sea ◽  
Primary Production ◽  
South China ◽  
Mesoscale Eddies ◽  
The South China Sea ◽  
The South ◽  
Monsoon Period ◽  
China Sea

scholarly journals Synoptic-Dynamic Analysis of Early Dry-Season Rainfall Events in the Vietnamese Central Highlands

2016 ◽  
Vol 144 (4) ◽  
pp. 1509-1527 ◽  
Author(s):  
Roderick van der Linden ◽  
Andreas H. Fink ◽  
Tan Phan-Van ◽  
Long Trinh-Tuan
Keyword(s):  
South China Sea ◽  
South China ◽  
Cold Front ◽  
Dry Season ◽  
The South China Sea ◽  
The South ◽  
Low Level ◽  
China Sea ◽  
Central Highlands ◽  
Wet Spells

Abstract The Central Highlands are Vietnam’s main coffee growing region. Unusual wet spells during the early dry season in November and December negatively affect two growing cycles in terms of yield and quality. The meteorological causes of wet spells in this region have not been thoroughly studied to date. Using daily rain gauge measurements at nine stations for the period 1981–2007 in the Central Highlands, four dynamically different early dry-season rainfall cases were investigated in depth: 1) the tail end of a cold front, 2) a tropical depression–type disturbance, 3) multiple tropical wave interactions, and 4) a cold surge with the Borneo vortex. Cases 1 and 4 are mainly extratropically forced. In case 1, moisture advection ahead of a dissipating cold front over the South China Sea led to high equivalent potential temperature in the southern highland where this air mass stalled and facilitated recurrent outbreaks of afternoon convection. In this case, the low-level northeasterly flow over the South China Sea was diverted around the southern highlands by relatively stable low layers. On the contrary, low-level flow was more orthogonal to the mountain barrier and high Froude numbers and concomitant low stability facilitated the westward extension of the rainfall zone across the mountain barrier in the other cases. In case 3, an eastward-traveling equatorial Kelvin wave might have been a factor in this westward extension, too. The results show a variety of interactions of large-scale wave forcings, synoptic-convective dynamics, and orographic effects on spatiotemporal details of the rainfall patterns.

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