Accuracy of spatio-temporal RARX model predictions of water table depths

2002 ◽  
Vol 16 (2) ◽  
pp. 112-126 ◽  
Author(s):  
M. Knotters ◽  
M. F. P. Bierkens
Keyword(s):  
Water Table ◽  
Model Predictions ◽  
Spatio Temporal

scholarly journals Spatial variability in tropospheric peroxyacetyl nitrate in the tropics from infrared satellite observations in 2005 and 2006

2016 ◽  
Author(s):  
Vivienne H. Payne ◽  
Emily V. Fischer ◽  
John R. Worden ◽  
Zhe Jiang ◽  
Liye Zhu ◽  
...  
Keyword(s):  
Central Africa ◽  
Satellite Observations ◽  
Biogenic Emissions ◽  
Tropical Atlantic ◽  
Peroxyacetyl Nitrate ◽  
Fire Emissions ◽  
Model Predictions ◽  
Spatio Temporal ◽  
The Tropics ◽  
In Fire

Abstract. Peroxyacetyl nitrate (PAN) plays a fundamental role in the global ozone budget and is the primary reservoir of tropospheric reactive nitrogen over much of the globe. However, large uncertainties exist in how surface emissions, transport and lightning affect the global distribution, particularly in the tropics. We present new satellite observations of free tropospheric PAN in the tropics from the Aura Tropospheric Emission Spectrometer. This dataset allows us to test expected spatio-temporal distributions that have been predicted by models but previously not well observed. We compare here with the GEOS-Chem model with updates specifically for PAN. We observe an austral springtime maximum over the tropical Atlantic, a feature that model predictions attribute primarily to lightning. Over Northern Central Africa in December, observations show strong inter-annual variability, despite low variation in fire emissions, that we attribute to the combined effects of changes in biogenic emissions and lightning. We observe small enhancements in free tropospheric PAN corresponding to the extreme burning event over Indonesia associated with the 2006 El Nino.

scholarly journals Improving the Accuracy of Hydrodynamic Model Predictions Using Lagrangian Calibration

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 575 ◽  
Author(s):  
Neda Mardani ◽  
Kabir Suara ◽  
Helen Fairweather ◽  
Richard Brown ◽  
Adrian McCallum ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Field Measurements ◽  
Hydrodynamic Models ◽  
Lagrangian Drifters ◽  
Lagrangian Velocity ◽  
Model Predictions ◽  
Spatio Temporal ◽  
Lagrangian Data ◽  
Lagrangian Drifter ◽  
Recent Attention

While significant studies have been conducted in Intermittently Closed and Open Lakes and Lagoons (ICOLLs), very few have employed Lagrangian drifters. With recent attention on the use of GPS-tracked Lagrangian drifters to study the hydrodynamics of estuaries, there is a need to assess the potential for calibrating models using Lagrangian drifter data. Here, we calibrated and validated a hydrodynamic model in Currimundi Lake, Australia using both Eulerian and Lagrangian velocity field measurements in an open entrance condition. The results showed that there was a higher level of correlation (R2 = 0.94) between model output and observed velocity data for the Eulerian calibration compared to that of Lagrangian calibration (R2 = 0.56). This lack of correlation between model and Lagrangian data is a result of apparent difficulties in the use of Lagrangian data in Eulerian (fixed-mesh) hydrodynamic models. Furthermore, Eulerian and Lagrangian devices systematically observe different spatio-temporal scales in the flow with larger variability in the Lagrangian data. Despite these, the results show that Lagrangian calibration resulted in optimum Manning coefficients (n = 0.023) equivalent to those observed through Eulerian calibration. Therefore, Lagrangian data has the potential to be used in hydrodynamic model calibration in such aquatic systems.

scholarly journals Water table fluctuation and its effects on vegetation in a semiarid environment

2011 ◽  
Vol 8 (2) ◽  
pp. 3271-3304 ◽  
Author(s):  
L. Duan ◽  
T. Liu ◽  
X. Wang ◽  
Y. Luo ◽  
W. Wang ◽  
...  
Keyword(s):  
Water Table ◽  
Vegetation Index ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Depth Map ◽  
Northern China ◽  
Temporal Variations ◽  
Water Table Fluctuation ◽  
Semiarid Environment ◽  
Spatio Temporal

Abstract. A good understanding of water table fluctuation effects on vegetation is crucial for sustaining fragile hydrology and ecology of semiarid areas such as the Horqin Sandy Land (HSL) in northern China, but such understanding is not well documented in literature. The objectives of this study were to examine spatio-temporal variations of water table and their effects on vegetation in a semiarid environment. A 9.71 km2 area within the HSL was chosen and well-instrumented to continuously measure hydrometeorologic parameters (e.g., water table). The area comprises of meadow lands and sandy dunes as well as transitional zones in between. In addition to those measured data, this study also used Landsat TM and MODIS imageries and meteorological data at a station near the study area. The spatio-temporal variations were examined using visual plots and contour maps, while the effects on vegetation were determined by overlaying a water table depth map with a vegetation index map derived from the MODIS imageries. The results indicated that water table was mainly dependent on local topography, localized geological settings, and human activities (e.g., reclamation). At annual and monthly scales, water table was mainly a function of precipitation and potential evapotranspiration. A region within the study area where depth to water table was smaller tended to have better (i.e., more dense and productive) vegetation cover. Further, the results revealed that water table fluctuation was more sensitive for vegetations in the meadow lands than in the transitional zones, but it was least sensitive for vegetations in the sandy dunes.

scholarly journals Hydrologic processes of groundwater in a small monsoon-influenced mountainous watershed

2018 ◽  
Vol 49 (6) ◽  
pp. 2016-2029 ◽  
Author(s):  
Ruiqiang Yuan ◽  
Shiqin Wang ◽  
Lihu Yang ◽  
Jianrong Liu ◽  
Peng Wang ◽  
...  
Keyword(s):  
Water Table ◽  
Northern China ◽  
Temporal Variations ◽  
Hydrologic Processes ◽  
Mountain Valley ◽  
Mountain Watersheds ◽  
Mountainous Watershed ◽  
The Mean ◽  
Spatio Temporal ◽  
In The Beginning

Abstract Mountain block recharge is the least well quantified owing to the lack of a thorough understanding of mountain block hydrological processes. Observations of spatio-temporal variations of groundwater were employed to clarify hydrologic processes in a semi-arid mountainous watershed of northern China. Results showed that the annual feeding rate of precipitation changed between 21% and 40%. However, infiltration of precipitation was mainly drained as interflow on slopes and recharged into the mountain valley as focused recharge. As a result, the mean correlation coefficient between precipitation and groundwater level was only 0.20 and seasonal variations were reduced. Mountain slope is essentially impermeable with no bedrock percolation under arid circumstances. Only a bedrock percolation event occurred after multiple closely-spaced heavy rains during the four-year observation, which induced a local rapid ascending of the water table and an enhanced lateral recharge from upgradient watersheds. The influence of the enhanced lateral recharge lasted three years, suggesting a huge groundwater catchment overcoming local watershed divides in mountain blocks. The average of the gradual recession of the water table was 5.1 mm/d with a maximum of 11.4 mm/d in the beginning stage. Both interflow and bedrock percolation are important. Our results highlight the changeability of hydrologic processes in mountain watersheds.

scholarly journals Development of a Coupled Land Surface Hydrologic Model and Evaluation at a Critical Zone Observatory

2013 ◽  
Vol 14 (5) ◽  
pp. 1401-1420 ◽  
Author(s):  
Yuning Shi ◽  
Kenneth J. Davis ◽  
Christopher J. Duffy ◽  
Xuan Yu
Keyword(s):  
Latent Heat ◽  
Water Table ◽  
Land Surface ◽  
Hydrologic Model ◽  
Heat Fluxes ◽  
Water Table Depth ◽  
Surface Model ◽  
Land Surface Scheme ◽  
Model Predictions ◽  
Surface Scheme

Abstract A fully coupled land surface hydrologic model, Flux-PIHM, is developed by incorporating a land surface scheme into the Penn State Integrated Hydrologic Model (PIHM). The land surface scheme is adapted from the Noah land surface model. Because PIHM is capable of simulating lateral water flow and deep groundwater at spatial resolutions sufficient to resolve upland stream networks, Flux-PIHM is able to represent heterogeneities due to topography and soils at high resolution, including spatial structure in the link between groundwater and the surface energy balance (SEB). Flux-PIHM has been implemented at the Shale Hills watershed (0.08 km2) in central Pennsylvania. Multistate observations of discharge, water table depth, soil moisture, soil temperature, and sensible and latent heat fluxes in June and July 2009 are used to manually calibrate Flux-PIHM at hourly temporal resolution. Model predictions from 1 March to 1 December 2009 are evaluated. Both hydrologic predictions and SEB predictions show good agreement with observations. Comparisons of model predictions between Flux-PIHM and the original PIHM show that the inclusion of the complex SEB simulation only brings slight improvement in hourly model discharge predictions. Flux-PIHM adds the ability of simulating SEB to PIHM and does improve the prediction of hourly evapotranspiration, the prediction of total runoff (discharge), and the predictions of some peak discharge events, especially after extended dry periods. Model results reveal that annual average sensible and latent heat fluxes are strongly correlated with water table depth, and the correlation is especially strong for the model grids near the stream.

scholarly journals Evaluation of spatio-temporal dynamics of water table in NW Bangladesh: an integrated approach of GIS and Statistics

2016 ◽  
Vol 2 (3) ◽  
pp. 297-312 ◽  
Author(s):  
A. T. M. Sakiur Rahman ◽  
Md. Kamruzzaman ◽  
Chowdhury Sarwar Jahan ◽  
Quamrul Hasan Mazumder ◽  
Ahammad Hossain
Keyword(s):  
Water Table ◽  
Temporal Dynamics ◽  
Integrated Approach ◽  
Spatio Temporal

scholarly journals Coordination of contractility, adhesion and flow in migrating Physarum amoebae

2015 ◽  
Vol 12 (106) ◽  
pp. 20141359 ◽  
Author(s):  
Owen L. Lewis ◽  
Shun Zhang ◽  
Robert D. Guy ◽  
Juan C. del Álamo
Keyword(s):  
Particle Image ◽  
Amoeboid Motility ◽  
Image Velocimetry ◽  
Model Predictions ◽  
Spatio Temporal ◽  
Adhesive Interactions ◽  
The Relationship ◽  
Generate Model ◽  
Adhesive Forces ◽  
Traction Stress

This work examines the relationship between spatio-temporal coordination of intracellular flow and traction stress and the speed of amoeboid locomotion of microplasmodia of Physarum polycephalum . We simultaneously perform particle image velocimetry and traction stress microscopy to measure the velocity of cytoplasmic flow and the stresses applied to the substrate by migrating Physarum microamoebae. In parallel, we develop a mathematical model of a motile cell which includes forces from the viscous cytosol, a poro-elastic, contractile cytoskeleton and adhesive interactions with the substrate. Our experiments show that flow and traction stress exhibit back-to-front-directed waves with a distinct phase difference. The model demonstrates that the direction and speed of locomotion are determined by this coordination between contraction, flow and adhesion. Using the model, we identify forms of coordination that generate model predictions consistent with experiments. We demonstrate that this coordination produces near optimal migration speed and is insensitive to heterogeneity in substrate adhesiveness. While it is generally thought that amoeboid motility is robust to changes in extracellular geometry and the nature of extracellular adhesion, our results demonstrate that coordination of adhesive forces is essential to producing robust migration.

scholarly journals Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study

2010 ◽  
Vol 7 (3) ◽  
pp. 3931-3976
Author(s):  
H. Li ◽  
M. Sivapalan ◽  
F. Tian ◽  
D. Liu
Keyword(s):  
Annual Runoff ◽  
Tile Drainage ◽  
The Other ◽  
Distributed Model ◽  
Nitrogen Storage ◽  
Nutrient Balances ◽  
Model Predictions ◽  
Dry Conditions ◽  
Spatio Temporal ◽  
Central Illinois

Abstract. This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in Central Illinois, Mid-West of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

scholarly journals ASSESSMENT OF SPATIO-TEMPORAL FLUCTUATIONS IN GROUNDWATER LEVEL AND ITS IMPACT ON TUBEWELL ENERGY NEXUS

2020 ◽  
pp. 161-165
Author(s):  
Hafiz M. Awais ◽  
Aamir Shakoor
Keyword(s):  
Water Table ◽  
Groundwater Level ◽  
Groundwater Resources ◽  
Management Strategies ◽  
Canal Water ◽  
Shallow Water Table ◽  
Total Cost ◽  
North East ◽  
Spatio Temporal ◽  
Over Exploitation

Over exploitation of groundwater to fulfill the crop water requirements due to insufficient canal water supply can pose a major threat of water table lowering in semi-arid regions like Pakistan. So, it is necessary to analyze the seasonal groundwater level variations for appropriate management strategies to sustainable groundwater use. Water table declining has adverse economic impacts on total cost of agricultural inputs, as more than 50% of irrigation demand is being fulfilled from groundwater resources. Therefore, this research was aimed to draw the groundwater level zones and to determine the impacts of lowering water table on tubewell energy nexus in district Hafizabad, Pakistan. Water table depth was categorized in three zones i.e., shallow (<10 m), moderate (10-15 m) and deep (>15 m) for years 2003, 2008 and 2013. It was found that water table was shallow on north-east boundary, moderate on the Centre and deep on west-south boundary. During the study period, the area under shallow water table zone reduced from 38.6 to 23%, moderate area expanded from 52.3 to 59.2% and deep area increased from 9.1 to 17.9%. The difference between total cost of shallow and moderate water table was minor. The total cost (construction and operational) of tubewell for 36 m deep water table was 3 times higher than shallow depth (9 m). Thus, lowering of water table should be controlled by increasing share of canal water in deeper zone and introducing artificial recharge methods

scholarly journals Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study

2010 ◽  
Vol 14 (11) ◽  
pp. 2259-2275 ◽  
Author(s):  
H. Li ◽  
M. Sivapalan ◽  
F. Tian ◽  
D. Liu
Keyword(s):  
Annual Runoff ◽  
Tile Drainage ◽  
The Other ◽  
Distributed Model ◽  
Nitrogen Storage ◽  
Nutrient Balances ◽  
Model Predictions ◽  
Dry Conditions ◽  
Spatio Temporal ◽  
Central Illinois

Abstract. This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

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