An improved ecological model and software for short-term algal bloom forecasting

Zhang, Hongju; Hu, Weiping; Gu, Kai; Li, Qin‐Qin; Zheng, Daolin; Zhai, Shikui

doi:10.1016/j.envsoft.2013.07.001

Cited by 55 publications

(36 citation statements)

References 24 publications

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“…The model includes three modules: a relatively independent hydrodynamics module, a food chain network module, and a material transform and transport module. The model has been used to study water transfers from the Yangtze River to Taihu Lake [66] and to predict algal blooms [52]. The model parameterization, initialization, and forcing functions as well as other details can be found in [33], while the data assimilation method can be found in [43].…”

Section: Data Assimilation Results Using Default Chla and New Chla: Amentioning

confidence: 99%

“…The second was based on physical and biological processes, which could reveal controlling factors and causal relationships [75][76][77][78][79][80]. For Taihu Lake, such process-oriented models have been developed and used to study hydrodynamics and biological response to physical forcing [33,52,81,82]. However, application of such a model together with MODIS data assimilation revealed large-scale artifacts, where the reasons need to be further diagnosed.…”

Section: Discussionmentioning

confidence: 99%

“…The drainage basin covers some of the most developed regions in China including Jiangsu, Zhejiang, and Anhui Provinces and the Shanghai Municipality, which contributed ~10% of China's GDP with only 0.4% of China's territory [51,52]. In recent years, increasing eutrophication and cyanobacterial blooms have been reported, posing a significant threat the environment and humans who rely on the lake for drinking water, tourism, aquaculture, recreation, and other activities [9,53].…”

Section: Study Areamentioning

confidence: 99%

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An EOF-Based Algorithm to Estimate Chlorophyll a Concentrations in Taihu Lake from MODIS Land-Band Measurements: Implications for Near Real-Time Applications and Forecasting Models

Duan

et al. 2014

Remote Sensing

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For near real-time water applications, the Moderate Resolution Imaging Spectroradiometers (MODIS) on Terra and Aqua are currently the only satellite instruments that can provide well-calibrated top-of-atmosphere (TOA) radiance data over the global aquatic environments. However, TOA radiance data in the MODIS ocean bands over turbid atmosphere in east China often saturate, leaving only four land bands to use. In this study, an approach based on Empirical Orthogonal Function (EOF) analysis has been developed and validated to estimate chlorophyll a concentrations (Chla, μg/L) in surface waters of Taihu Lake, the third largest freshwater lake in China. The EOF approach analyzed the spectral variance of normalized Rayleigh-corrected reflectance (Rrc) data at 469, 555, 645, and 859 nm, and subsequently related that variance to Chla using 28 concurrent MODIS and field measurements. This empirical algorithm was then validated using another 30 independent concurrent MODIS and field measurements. Image analysis and radiative transfer simulations indicated that the algorithm appeared to be tolerant to aerosol perturbations, with unbiased RMS uncertainties of <80% for Chla ranging between 3 and 100 μg/L. Application OPEN ACCESSRemote Sens. 2014, 6 10695 of the algorithm to a total of 853 MODIS images between 2000 and 2013 under cloud-free conditions revealed spatial distribution patterns and seasonal changes that are consistent to previous findings based on floating algae mats. The current study can provide additional quantitative estimates of Chla that can be assimilated in an existing forecast model, which showed improved performance over the use of a previous Chla algorithm. However, the empirical nature, relatively large uncertainties, and limited number of spectral bands all point to the need of further improvement in data availability and accuracy with future satellite sensors.

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Section: Data Assimilation Results Using Default Chla and New Chla: Amentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

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An EOF-Based Algorithm to Estimate Chlorophyll a Concentrations in Taihu Lake from MODIS Land-Band Measurements: Implications for Near Real-Time Applications and Forecasting Models

Duan

et al. 2014

Remote Sensing

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“…The Ecotaihu model is vertical-compressed, three-dimensional ecological model that involves hydrodynamic, nutrient cycling and food chain network modules (Hu et al 2006). The model has been verified and validated by many observations, and continuously been improved (Hu et al 2006(Hu et al , 2011Zhang et al 2013). Its new structure (Zhang et al 2013) is shown in Fig.…”

Section: Ecotaihu Modelmentioning

confidence: 96%

Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study

Zhai³

2015

Environmental Management

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Algal blooms have recently become one of the most serious environmental problems in eutrophic freshwater ecosystems worldwide. Although many observation and simulation approaches have been applied to predict algal blooms, few studies have addressed the alert levels of algal blooms using integrative indicators in a large lake with multiple service function and significant horizontal heterogeneity. This study developed an integrative indicator assessment system (IIAS) to rank the alert level of algal blooms. In the IIAS, algal biomass, area percentage, distance from drinking water intake points, distance from scenic zones and duration of algal bloom were used as indicators to calculate a comprehensive alert level, which was classified into five grades (Vigilance, Low, Moderate, High, and Severe). Lake Taihu was taken as a case study to assess the comprehensive alert level of algal blooms in 2007 and 2010. The comprehensive alert level showed obvious spatial-temporal patterns, with an acceptable accuracy in Lake Taihu. The comprehensive alert levels were relatively higher in typical phytoplankton subzones than typical hydrophytes subzones and are more sensitive to weight factor in the northern and western subzones where high biomass usually occurs. Case study showed a very good application of the proposed comprehensive alert level assessment methodology, which can be adjusted to predict the degree of hazard of algal blooms in multi-service function large lakes to help the government and decision makers to act to prevent the disaster from algal bloom spreading.

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“…In this paper, numerical models are used to study the hydrodynamics and water quality of Taihu Lake under steady and unsteady wind conditions. Even though, over 20 studies have been carried out using two or three-dimensional numerical models before this study, their focus is either on the resulting water quality index or on the ecological status, and none of them are dedicated to a thorough, quantitative description of (wind induced) large-scale hydrodynamic circulation itself, nor to the implication of hydrodynamic circulation to environment or ecology in this lake [25,31,32].…”

Section: Introductionmentioning

confidence: 99%

Horizontal Circulation Patterns in a Large Shallow Lake: Taihu Lake, China

Liu

et al. 2018

Water

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Abstract:Wind induced hydrodynamic circulations play significant roles in the transport and mixing process of pollutants and nutrients in large shallow lakes, but they have been usually overlooked, while environmental, biological, and ecological aspects of eutrophication problems get the most focus. Herein we use a three-dimensional model, driven by steady/unsteady wind, river discharge, rainfall, evaporation to investigate the spatially heterogeneous, large-scale hydrodynamic circulations and their role in transporting and mixing mechanisms in Taihu Lake. Wind direction and velocity determines the overall hydrodynamic circulation structure, i.e. direction, intensity, and position. A relative stable hydrodynamic circulation pattern has been formed shortly with steady wind (~2 days). Vertical profiles of horizontal velocities are linearly correlated to the relative shallowness of water depth. Volume exchange between subbasins, influenced by wind speed and initial water level, differs due to the complex topography and irregular shape. With unsteady wind, these findings are still valid to a high degree. Vertical variations in hydrodynamic circulation are important in explaining the surface accumulation of algae scums in Meiliang Bay in summers. Vorticity of velocity field, a key indicator of hydrodynamic circulation, is determined by wind direction, bathymetry gradient, and water depth. The maximum change of velocity vorticity happens when wind direction is perpendicular to bathymetry gradient. Furthermore, Lagrangian-based tracer transport is used to estimate emergency pollution leakage impacts, and also to evaluate operational management measurements, such as, the large-scale water transfer. The conclusion is that the large-scale water transfer does not affect the hydrodynamic circulation and volume exchanges between subbasins significantly, but succeeds to transport and then mix the fresh, clean Yangtze River water to a majority area of Taihu Lake.

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An improved ecological model and software for short-term algal bloom forecasting

Cited by 55 publications

References 24 publications

An EOF-Based Algorithm to Estimate Chlorophyll a Concentrations in Taihu Lake from MODIS Land-Band Measurements: Implications for Near Real-Time Applications and Forecasting Models

An EOF-Based Algorithm to Estimate Chlorophyll a Concentrations in Taihu Lake from MODIS Land-Band Measurements: Implications for Near Real-Time Applications and Forecasting Models

Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study

Horizontal Circulation Patterns in a Large Shallow Lake: Taihu Lake, China

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