Analyzing impacts of seasonality and landscape gradient on event-scale nitrate-discharge dynamics based on nested high-frequency monitoring

2020 ◽  
Vol 591 ◽  
pp. 125585
Author(s):  
Xiaolin Zhang ◽  
Xiaoqiang Yang ◽  
Seifeddine Jomaa ◽  
Michael Rode
Keyword(s):  
High Frequency ◽  
Event Scale ◽  
Frequency Monitoring ◽  
Landscape Gradient

scholarly journals High-frequency monitoring reveals seasonal and event-scale water quality variation in a temporally frozen river

2018 ◽  
Vol 564 ◽  
pp. 619-639 ◽  
Author(s):  
M. Kämäri ◽  
S. Tattari ◽  
E. Lotsari ◽  
J. Koskiaho ◽  
C.E.M. Lloyd
Keyword(s):  
Water Quality ◽  
High Frequency ◽  
Event Scale ◽  
Water Quality Variation ◽  
Frequency Monitoring ◽  
Quality Variation

scholarly journals Drivers of nitrogen and phosphorus dynamics in a groundwater-fed urban catchment revealed by high frequency monitoring

2020 ◽  
Author(s):  
Liang Yu ◽  
Joachim C. Rozemeijer ◽  
Hans Peter Broers ◽  
Boris M. van Breukelen ◽  
Jack J. Middelburg ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Column ◽  
High Frequency ◽  
Water Bodies ◽  
Organic N ◽  
Hydrological Process ◽  
Nitrogen And Phosphorus ◽  
Urban Catchment ◽  
Event Scale ◽  
Frequency Monitoring

Abstract. Eutrophication of water bodies has been a problem causing severe degradation of water quality in cities. To gain mechanistic understanding of the temporal dynamics of nitrogen and phosphorus in a groundwater fed low-lying urban polder, we applied high frequency monitoring in Geuzenveld, a polder in the city of Amsterdam. The high frequency monitoring equipment was installed at the pumping station where water leaves the polder. From 2016 March to 2017 June, total phosphorus (TP), ammonium (NH4), turbidity, electrical conductivity (EC), and water temperature were measured at intervals smaller than 20 minutes. This paper discusses the results at three time scales: annual scale, rain event scale, and single pumping event scale. Mixing of upwelling groundwater and runoff was the dominant hydrological process and governed the temporal pattern of the EC, while N and P fluxes from the polder were also significantly regulated by primary production and iron transformations. The mixing of groundwater and runoff water governed water quality through variation of the intensity and duration of the events. For NH4, the dominant form of N in surface water originating from groundwater seepage, we observed low concentrations during the algae growing season, while concentrations were governed by mixing of groundwater and precipitation inputs in the late autumn and winter. The depletion of dissolved NH4 in spring suggests uptake by primary producers, consistent with high chlorophyll-a, O2, and suspended solids during this period. Total P and turbidity were high during winter, due to the release of reduced iron and P from anoxic sediment to the water column. Rapid Fe2+ oxidation in the water column is the major cause of turbidity. In the other seasons, P is retained in the sediment by iron oxides. Nitrogen is exported from the polder to the downstream water bodies throughout the whole year, mostly in the form of NH4, but as organic N in spring. P leaves the polder mainly during winter, primarily associated with Fe(OH)3 colloids and as dissolved P. Based on this new understanding of the dynamics of N and P in this low lying urban catchment, it is possible to formulate management strategies that can effectively control and reduce eutrophication situation in urban polders and receiving downstream waters.

scholarly journals Drivers of nitrogen and phosphorus dynamics in a groundwater-fed urban catchment revealed by high-frequency monitoring

2021 ◽  
Vol 25 (1) ◽  
pp. 69-87
Author(s):  
Liang Yu ◽  
Joachim C. Rozemeijer ◽  
Hans Peter Broers ◽  
Boris M. van Breukelen ◽  
Jack J. Middelburg ◽  
...  
Keyword(s):  
Surface Water ◽  
Iron Oxides ◽  
High Frequency ◽  
Temporal Dynamics ◽  
Organic N ◽  
Rain Event ◽  
Hydrological Process ◽  
Urban Catchment ◽  
Event Scale ◽  
Frequency Monitoring

Abstract. Eutrophication of water bodies has been a problem causing severe degradation of water quality in cities. To gain mechanistic understanding of the temporal dynamics of nitrogen (N) and phosphorus (P) in a groundwater-fed low-lying urban polder, we applied high-frequency monitoring in Geuzenveld, a polder in the city of Amsterdam. The high-frequency monitoring equipment was installed at the pumping station where water leaves the polder. From March 2016 to June 2017, total phosphorus (TP), ammonium (NH4), turbidity, electrical conductivity (EC), and water temperature were measured at intervals of less than 20 min. This paper discusses the results at three timescales: annual scale, rain event scale, and single pumping event scale. Mixing of upwelling groundwater (main source of N and P) and runoff from precipitation on pavements and roofs was the dominant hydrological process governing the temporal pattern of the EC, while N and P fluxes from the polder were also regulated by primary production and iron transformations. In our groundwater-seepage controlled catchment, NH4 appeared to be the dominant form of N with surface water concentrations in the range of 2–6 mg N L−1, which stems from production in an organic-rich subsurface. The concentrations of NH4 in the surface water were governed by the mixing process in autumn and winter and were reduced down to 0.1 mg N L−1 during the algal growing season in spring. The depletion of dissolved NH4 in spring suggests uptake by primary producers, consistent with high concentrations of chlorophyll a, O2, and suspended solids during this period. Total P and turbidity were high during winter (range 0.5–2.5 mg P L−1 and 200–1800 FNU, respectively, where FNU represents Formazin Nephelometric Unit) due to the release of P and reduced iron from anoxic sediment to the water column, where Fe2+ was rapidly oxidized and precipitated as iron oxides which contributed to turbidity. In the other seasons, P is retained in the sediment by sorption to precipitated iron oxides. Nitrogen is exported from the polder to the receiving waters throughout the whole year, mostly in the form of NH4 but in the form of organic N in spring. P leaves the polder mainly during winter, primarily associated with Fe(OH)3 colloids and as dissolved P. Based on this new understanding of the dynamics of N and P in this low-lying urban catchment, we suggested management strategies that may effectively control and reduce eutrophication in urban polders and receiving downstream waters.

scholarly journals High-resolution monitoring of nutrients in groundwater and surface waters: process understanding, quantification of loads and concentrations, and management applications

2016 ◽  
Vol 20 (9) ◽  
pp. 3619-3629 ◽  
Author(s):  
Frans C. van Geer ◽  
Brian Kronvang ◽  
Hans Peter Broers
Keyword(s):  
High Resolution ◽  
High Frequency ◽  
Temporal Trends ◽  
Surface Water Quality ◽  
Mitigation Measures ◽  
Nutrient Concentrations ◽  
Special Issue ◽  
Monitoring Strategies ◽  
Frequency Monitoring ◽  
Water Quality And Quantity

Abstract. Four sessions on "Monitoring Strategies: temporal trends in groundwater and surface water quality and quantity" at the EGU conferences in 2012, 2013, 2014, and 2015 and a special issue of HESS form the background for this overview of the current state of high-resolution monitoring of nutrients. The overview includes a summary of technologies applied in high-frequency monitoring of nutrients in the special issue. Moreover, we present a new assessment of the objectives behind high-frequency monitoring as classified into three main groups: (i) improved understanding of the underlying hydrological, chemical, and biological processes (PU); (ii) quantification of true nutrient concentrations and loads (Q); and (iii) operational management, including evaluation of the effects of mitigation measures (M). The contributions in the special issue focus on the implementation of high-frequency monitoring within the broader context of policy making and management of water in Europe for support of EU directives such as the Water Framework Directive, the Groundwater Directive, and the Nitrates Directive. The overview presented enabled us to highlight the typical objectives encountered in the application of high-frequency monitoring and to reflect on future developments and research needs in this growing field of expertise.

MEASURING SHOCK IN FINANCIAL MARKETS

2000 ◽  
Vol 03 (03) ◽  
pp. 347-355 ◽  
Author(s):  
GILLES O. ZUMBACH ◽  
MICHEL M. DACOROGNA ◽  
JØRGEN L. OLSEN ◽  
RICHARD B. OLSEN
Keyword(s):  
Financial Markets ◽  
High Frequency ◽  
Foreign Exchange Market ◽  
Exchange Market ◽  
Time Intervals ◽  
Event Scale ◽  
Time Horizons ◽  
Richter Scale ◽  
Market Shocks ◽  
Short Time

Analogous to the Richter scale for earthquakes, we introduce the Scale of Market Shocks (SMS), an "event" scale to quantify the size of shocks in financial markets. It is based on price volatilities and computed by integrating volatilities over time horizons ranging from 1 hour to 42 days. The SMS is computed using quality high frequency market data and can be constructed for any market. We compute the SMS for the foreign exchange market. For two major FX rates, we study the relation between SMS peaks and major "world events". We measure also the correlation between the Scale of Market Shocks index and the size of the subsequent price movements and show a high correlation for short time intervals.

Lena River biogeochemistry resolved by a high frequency monitoring: comparing a wet and a dry year

2021 ◽  
Author(s):  
Bennet Juhls ◽  
Anne Morgenstern ◽  
Pier Paul Overduin
Keyword(s):  
Organic Carbon ◽  
High Frequency ◽  
Monitoring Program ◽  
The Arctic ◽  
Lena River ◽  
O Isotopes ◽  
The Arctic Ocean ◽  
Frequency Monitoring ◽  
Biogeochemical Parameters ◽  
Doc Flux

<p>River biogeochemistry at any location integrates environmental processes over a definable upstream area of the river watershed. Therefore, biogeochemical parameters of river water are powerful indicators of the climate change impact on the entire watershed and smaller parts of it.</p><p>The current warming of the Siberian Arctic is changing atmospheric forcing, precipitation, subsurface water storage, and runoff from rivers to the Arctic Ocean. A number of studies predict an increase of organic carbon export by rivers into the Arctic Ocean with further warming of the Arctic. Major potential drivers for this increase are the rise of river discharge and permafrost thaw, which mobilizes organic matter.</p><p>Here, we present results of high frequency monitoring program of the Lena River waters in the central part of its delta at the Laptev Sea. For the first time, a number of biogeochemical parameters such as dissolved organic carbon (DOC), coloured dissolved organic matter, electrical conductivity, temperature, and d<sup>18</sup>O isotopes were measured at an interval of every few days throughout the entire season. Currently, the data set comprises two complete years from the spring 2018 until the spring 2020, which were characterized by extremely high and low summer discharges, respectively. While 2018 to 2019 was the fourth highest on record from 1936 to present, resulting in an annual DOC flux of 6.8 Tg C yr<sup>-1</sup>, 2019 was the sixth lowest discharge year with a significantly lower DOC flux of 4.5 Tg C yr<sup>-1</sup>. Endmember analysis using electrical conductivity and d<sup>18</sup>O isotopes showed that rainwater transported less DOC in 2019 (1.5 Tg C) than in 2018 (2.9 Tg C) although the winter base flow and the snow and ice meltwater transported similar amounts.</p><p>The biogeochemical response of the Lena River water provides us with new insights into the catchment processes, including permafrost thaw and potential mobilization of previously frozen organic carbon. Our new monitoring program will serve 1) as a baseline to measure future changes and 2) as a training dataset to project changes under future climate scenarios.</p>

Beyond high frequency monitoring: an optimised automatic sampling

2021 ◽  
Author(s):  
Jérémy Mougin
Keyword(s):  
Organic Matter ◽  
Water Body ◽  
High Frequency ◽  
Passive Samplers ◽  
Size Exclusion ◽  
Strong Impact ◽  
Small Stream ◽  
Automatic Sampling ◽  
Frequency Monitoring ◽  
On Line

<p>Beyond high frequency monitoring : an optimised automatic sampling</p><p>Mougin Jérémy, Superville Pierre-Jean, Cornard Jean-Paul, Billon Gabriel</p><p> </p><p>In order to improve the representativity of samples when monitoring a water body, efforts have been made these last years to develop new methodologies to replace grab samples. Passive samplers have allowed to have measurement averaged over several days and represented a first step. High frequency monitoring (usually one measure per hour), either in situ or on-line, led to the observations of daily cycles or transitory phenomena that were not suspected beforehand.</p><p>However, such method is usually difficult to implement for some trace analytes (e.g. trace metals or pesticides) or for some specific analysis (e.g. size exclusion chromatography on natural organic matter). Automatic sampling and analysis in the lab can be a solution, but it becomes very labor intensive as soon as the sampling frequency is high. Luck is also needed as a long sampling period can sometimes lead to very few variations if the water system is stable. In order to optimise the automatic sampling, a new methodology has been developped in this project.</p><p>A multiparameter probe measuring general parameters (temperature, pH, turbidity, ORP, conductivity, dissolved oxygen and two fluorometers for organic matter) was coupled with an automatic filtering sampler. The data from the probe are processed on-line and an algorithm decides if the geochemical situation in the water body seems new enough to trigger the sampling, based on previously sampled waters. The aim of this device is to collect the right number of samples with the best representativeness of phenomena taking place in the environment.</p><p>This method will be tested over a year in 2021 in order to monitor the dissolved organic matter in a small stream with both rural and urban contamination. These high-frequency measurements and samplings could make it possible to better define the sources and dynamics of the organic matter that has a strong impact on the quality of watercourses.</p>

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