scholarly journals Variability and changes in Pearl River Delta water level: oceanic and atmospheric forcing perspectives

2021 ◽  
Author(s):  
Xiangbo Feng ◽  
Wei Zhang ◽  
Zhenglei Zhu ◽  
Amulya Chevuturi ◽  
Wenlong Chen
Keyword(s):  
Water Level ◽  
Pearl River Delta ◽  
Southern China ◽  
Northern South China Sea ◽  
River Delta ◽  
Pearl River ◽  
Decadal Variations ◽  
Oceanic Forcing ◽  
The Pearl River

AbstractUnderstanding water level (WL) fluctuations in river deltas is of importance for managing water resources and minimizing the impacts of floods and droughts. Here, we demonstrate the competing effects of atmospheric and oceanic forcing on multi-timescale variability and changes in the Pearl River Delta (PRD) WLs in southern China, using 52 years (1961–2012) of in-situ observations at 13 hydrological stations. PRD WL presents significant seasonal to decadal variations, with large amplitudes upstream related to strong variability of southern China rainfall, and with relatively small amplitudes at the coastal stations determined by sea level (SL) fluctuations of the northern South China Sea. We find that the strengths of atmospheric and oceanic forcing in PRD are not mutually independent, leading to a distinct contrast of WL–forcing relationships at upstream and coastal stations. In the transition zone, because of counteracts of atmospheric and oceanic forcing, no robust relationships are identified between WL and either of the forcing. We further show that in the drought season of the warm ENSO and PDO epochs, the effect of atmospheric (oceanic) forcing on PRD WL is largely enhanced (weakened), due to increased southern China rainfall and negative SL anomalies. Over the observation period, WL significantly decreased at upstream stations, by up to 28–42 mm/year for flood season, contrasting with the upward trends of <4.3 mm/year at coastal stations across all seasons. Southern China rainfall explains little of the observed WL trends, whilst SL rise is mostly responsible for the WL trends at coastal stations.

scholarly journals Basic Mechanical Parameter Relations of Soft Clay in Pearl River Delta

2014 ◽  
Vol 8 (1) ◽  
pp. 320-325 ◽  
Author(s):  
Zhangming Li ◽  
Na Qi ◽  
Zhibin Masumi ◽  
Weidi Lin
Keyword(s):  
Shear Strength ◽  
Pearl River Delta ◽  
Large Scale ◽  
Soft Clay ◽  
River Delta ◽  
Pearl River ◽  
Cylindrical Cavity Expansion ◽  
In Situ Data ◽  
The Pearl River

Basic parameters relations among CPT parameters, un-drained strength and other mechanical parameters of soft clay are presented based on an elastic-plastic solution for cylindrical cavity expansion for soil investigation in energy engineering. The relation between CPT parameters and shear strength from vane test is also presented based on the result. Thus, the CPT parameters can be determined directly by elastic parameters and shear strength or vane shear parameters and vice versa. That makes it possible to save the high test costs and provide theoretical formulas to avoid some tests which are limited due to the site and/or other condition. Results are compared between the relations and in situ data at a large-scale project in the Pearl River Delta. The results showed consistency between the relation and in situ data.

Distribution of alkylphenols in the Pearl River Delta and adjacent northern South China Sea, China

Chemosphere ◽  
2006 ◽  
Vol 63 (4) ◽  
pp. 652-661 ◽  
Author(s):  
Bing Chen ◽  
Jing-Chun Duan ◽  
Bi-xian Mai ◽  
Xiao-Jun Luo ◽  
Qing-Shu Yang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Pearl River Delta ◽  
Northern South China Sea ◽  
River Delta ◽  
Pearl River ◽  
China Sea ◽  
The Pearl River Delta ◽  
The Pearl River

scholarly journals MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data

2010 ◽  
Vol 10 (5) ◽  
pp. 2079-2089 ◽  
Author(s):  
X. Li ◽  
T. Brauers ◽  
M. Shao ◽  
R. M. Garland ◽  
T. Wagner ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
Southern China ◽  
Pearl River ◽  
Aerosol Extinction ◽  
Pearl River Delta Region ◽  
In Situ Data ◽  
The Pearl River Delta ◽  
The Pearl River ◽  
Radiative Transfer Modeling

Abstract. We performed MAX-DOAS measurements during the PRiDe-PRD2006 campaign in the Pearl River Delta region 50 km north of Guangzhou, China, for 4 weeks in June 2006. We used an instrument sampling at 7 different elevation angles between 3° and 90°. During 9 cloud-free days, differential slant column densities (DSCDs) of O4 (O2 dimer) absorptions between 351 nm and 389 nm were evaluated for 6 elevation angles. Here, we show that radiative transfer modeling of the DSCDS can be used to retrieve the aerosol extinction and the height of the boundary layer. A comparison of the aerosol extinction with simultaneously recorded, ground based nephelometer data shows excellent agreement.

scholarly journals Observation and modelling of OH and HO<sub>2</sub> concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

2011 ◽  
Vol 11 (4) ◽  
pp. 11311-11378 ◽  
Author(s):  
K. D. Lu ◽  
F. Rohrer ◽  
F. Holland ◽  
H. Fuchs ◽  
B. Bohn ◽  
...  
Keyword(s):  
Pearl River Delta ◽  
Southern China ◽  
River Delta ◽  
Rural Site ◽  
Pearl River ◽  
Recycling Process ◽  
Mixing Ratios ◽  
Suburban Areas ◽  
The Pearl River Delta ◽  
The Pearl River

Abstract. Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15–26) × 106 cm−3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1–0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the corresponding OH formation at PRD would be more important than the primary OH production from ozone and HONO. While the new isoprene mechanisms need to be confirmed by laboratory experiments, there is probably need for other, so far unidentified chemical processes to explain entirely the high OH levels observed in Southern China.

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