In-situ erosion of cohesive sediment in a large shallow lake experiencing long-term decline in wind speed

Abstract. Based on the long-term in-situ observations of aerosol particle number size distributions and meteorological parameters, the traffic restriction measures during the Sino-African Summit (4–6 November 2006) in Beijing, China have been found to be remarkably efficient in reducing the number concentration of aerosol particles, in particular Aitken and accumulation mode particles, and in improving the visibility. The influence of traffic restriction in Beijing on the particle concentrations differed for different particle sizes. More significant effects on fine particles with diameters ranging from 40 to 800 nm have been found. Based on statistical analysis of long-term observation, under comparable weather conditions, the source strength of the particles in Aitken and accumulation modes seemingly was reduced by 40–60% when the traffic restrictions were in place. It may be mainly due to the reduction of secondary particle formation. Our size-dependent aerosol data also indicate that measures led to reductions in particulate air pollution in the optically most important diameter range, whereas further vehicle control measures may lead to an increase in ultrafine particle formation from the gas phase if the condensational sink further decreased. Assuming that there were no traffic restrictions and with normal levels of the vehicle emissions, the visibilities during the Summit would have been lower by about 50%. The importance of the restrictions is highest when the wind speed is lower than 3 m s−1. The fact that over 95% cases with visual range lower than 5 km during 2004 to 2007 occurred when the local wind speed was lower than 3 m s−1 may suggest that future traffic restrictions will lead to significant improvements of visibility in Beijing.

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Sensitivity of phytoplankton to climatic factors in a large shallow lake revealed by column-integrated algal biomass from long-term satellite observations

Water Research ◽

10.1016/j.watres.2021.117786 ◽

2021 ◽

Vol 207 ◽

pp. 117786

Author(s):

Yuchao Zhang ◽

Minqi Hu ◽

Kun Shi ◽

Min Zhang ◽

Tao Han ◽

...

Keyword(s):

Shallow Lake ◽

Algal Biomass ◽

Climatic Factors ◽

Satellite Observations ◽

Large Shallow Lake

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Long-term succession of Microcystis genotypes is driven by hydrological conditions and anthropogenic nutrient loading in a large shallow lake

Journal of Hydrology ◽

10.1016/j.jhydrol.2022.127451 ◽

2022 ◽

pp. 127451

Author(s):

Shouliang Huo ◽

Zhe Xiao ◽

Xiaochuang Li ◽

Hanxiao Zhang ◽

Jingtian Zhang ◽

...

Keyword(s):

Shallow Lake ◽

Nutrient Loading ◽

Hydrological Conditions ◽

Large Shallow Lake

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Long-term wind induced internal response mechanisms at Meiliang Bay of large, shallow Lake Taihu

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2019026 ◽

2020 ◽

Vol 56 ◽

pp. 1

Author(s):

Abdul Jalil ◽

Ke Zhang ◽

Ling Qi ◽

Yiping Li

Keyword(s):

Shallow Lake ◽

Wind Field ◽

Lake Taihu ◽

Temporal Trends ◽

Lake Ecosystem ◽

Chl A ◽

Internal Response ◽

Large Shallow Lake ◽

Meiliang Bay

The internal response of shallow lakes to external factors is very important to investigate for understanding their role in long-term changes of the shallow lake ecosystem. The current study investigated the impacts of long-term wind dynamics on in-lake processes of the degraded shallow lake. The long-term high-frequency wind field, water quality, and Chlorophyll-a data analysis showed that there were two groups of variables found with higher internal similarity at Meiliang bay of large, shallow Lake Taihu. The temporal trends of wind, temperature, and Chl-a found highly consistent while dissolved oxygen (DO), total nitrogen (TN), total phosphorus (TP), suspended solids (SS) and Secchi depth were not significantly correlated in long-term temporal trends analysis. The results showed that Chl-a and other shallow lake ecosystem variables (abiotic) are strongly related to long-term wind field. The changes in nutrients and lower mixing scenarios trigger the growth of Chl-a and onshore lower winds help in the formation of colonies. There was a shift in wind and internal response variables before and after 2006. Wind and internal water quality parameters were highly variable before 2006 whereas, decline in wind speeds along with stable wind directional switching caused intense blooms formation along with thermal stratification (warming) for a longer period of time (after 2006) in the shoreline areas. The current study can help to understand the internal ecosystem response mechanisms in long-term interactions with wind field to control the eutrophication and algal blooms.

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In situ high-resolution evaluation of labile arsenic and mercury in sediment of a large shallow lake

The Science of The Total Environment ◽

10.1016/j.scitotenv.2015.09.037 ◽

2016 ◽

Vol 541 ◽

pp. 83-91 ◽

Cited By ~ 21

Author(s):

Chao Wang ◽

Yu Yao ◽

Peifang Wang ◽

Jun Hou ◽

Jin Qian ◽

...

Keyword(s):

High Resolution ◽

Shallow Lake ◽

Large Shallow Lake

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Traffic restrictions in Beijing during the Sino-African Summit 2006: aerosol size distribution and visibility compared to long-term in situ observations

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-7583-2008 ◽

2008 ◽

Vol 8 (24) ◽

pp. 7583-7594 ◽

Cited By ~ 38

Author(s):

Y. F. Cheng ◽

J. Heintzenberg ◽

B. Wehner ◽

Z. J. Wu ◽

H. Su ◽

...

Keyword(s):

Wind Speed ◽

Traffic Control ◽

Fine Particles ◽

Ultrafine Particle ◽

Weather Conditions ◽

Aerosol Size Distribution ◽

Wind Speeds ◽

In Situ Observations

Abstract. Based on the long-term in-situ observations of aerosol particle number size distributions and meteorological parameters, the measures of traffic restriction during the Sino-African Summit (4–6 November 2006) in Beijing, China have been found to be efficient in reducing the number concentration of aerosol particles, in particular Aitken and accumulation mode particles, and in improving the visibility when local emissions dominated. The influence of traffic restrictions on the particle concentrations differed for different particle sizes. More significant effects on fine particles with diameters ranging from 40 to 500 nm have been found. Based on statistical analysis of long-term observations, under comparable weather conditions, the number concentrations of the particles in Aitken and accumulation modes seemingly were reduced by 20–60% when the traffic restrictions were in place. This change may be mainly due to the reduction of secondary particle contributions. However, it is worth to notice that the reduction of 60% might overestimate the effect of the measures of traffic control, due to the inherent data shortage with very high wind speeds in the comparison data population. Our size-dependent aerosol data also indicate that measures led to reductions in particulate air pollution in the optically most important diameter range, whereas further vehicle restriction measures might lead to an increase in ultrafine particle formation if the condensational sink further decreased. Assuming that there were no traffic restrictions and with normal levels of the vehicle emissions, the visibilities during the Summit would have been lower by about 20–45%. The fact that over 95% cases with visibility range lower than 5 km during 2004 to 2007 occurred when the local wind speed was lower than 3 m s−1 may suggest that the importance of the emission restrictions is highest when the wind speed is lower than 3 m s−1, concerning the improvement of serious low visibility situations in Beijing.

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