scholarly journals Non-Negligible Lag of Groundwater Infiltration Recharge: A Case in Mu Us Sandy Land, China

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 561 ◽  
Author(s):  
Ze-Yuan Yang ◽  
Kai Wang ◽  
Yue Yuan ◽  
Jinting Huang ◽  
Zhi-Jun Chen ◽  
...  
Keyword(s):  
Groundwater Recharge ◽  
Heavy Rain ◽  
Observation Data ◽  
Sandy Land ◽  
Mu Us Sandy Land ◽  
Recharge Sources ◽  
Matrix Flow ◽  
Lag Times ◽  
Rain Events ◽  
Storm Rainfall

Groundwater is often the main source of available water, and precipitation is one of the main recharge sources of groundwater in arid and semi-arid regions. This paper studies a fixed dune in Mu Us Sandy Land in China, establishes a numerical model, acquires hydraulic parameters and heat parameters of the vadose zone, and calculates the recharge coefficient based on field observation data and numerical modelling. These measurement results show that the response depths of storm rain are more than 90 cm, while those of small rain events are less than 10 cm. The numerical results show that infiltration depths are 10 cm for small rain and more than 90 cm for middle rain respectively. The lag time of the water content at 90 cm below the surface was 25 h following a middle rain, 18–19 h following a heavy rain, and 16–18 h following a storm rainfall. Groundwater recharge lag times (matrix flow) varied from 11 h to 48 h. Excluded precipitation for groundwater recharge was 11.25–11.75 mm in 1 h when groundwater depth was 120 cm and 15–15.5 mm when 140 cm, showing significant influence in groundwater resource evaluation.

scholarly journals Comparison of Radar-Based Hail Detection Using Single- and Dual-Polarization

2019 ◽  
Vol 11 (12) ◽  
pp. 1436 ◽  
Author(s):  
Skripniková ◽  
Řezáčová
Keyword(s):  
Comparative Analysis ◽  
Heavy Rain ◽  
Radar Data ◽  
Severe Weather ◽  
Detection Methods ◽  
Polarimetric Radar ◽  
Dual Polarization ◽  
Rain Events ◽  
Single Polarization ◽  
Strong Agreement

The comparative analysis of radar-based hail detection methods presented here, uses C-band polarimetric radar data from Czech territory for 5 stormy days in May and June 2016. The 27 hail events were selected from hail reports of the European Severe Weather Database (ESWD) along with 21 heavy rain events. The hail detection results compared in this study were obtained using a criterion, which is based on single-polarization radar data and a technique, which uses dual-polarization radar data. Both techniques successfully detected large hail events in a similar way and showed a strong agreement. The hail detection, as applied to heavy rain events, indicated a weak enhancement of the number of false detected hail pixels via the dual-polarization hydrometeor classification. We also examined the performance of hail size detection from radar data using both single- and dual-polarization methods. Both the methods recognized events with large hail but could not select the reported events with maximum hail size (diameter above 4 cm).

Groundwater age from multi-level bores: What it can tell about the aquifers

2021 ◽  
Author(s):  
Uwe Morgenstern ◽  
Zara Rawlinson
Keyword(s):  
Groundwater Flow ◽  
Groundwater Recharge ◽  
Sea Level ◽  
Preferential Flow ◽  
Groundwater Age ◽  
Geological Processes ◽  
Recharge Sources ◽  
Transient Electromagnetic ◽  
Geophysical Surveys ◽  
Multi Level

<p>Geologic data to provide information on the functioning of aquifers is often scars. For the aquifers underlying the Heretaunga Plains, Hawkes Bay, one of New Zealand’s most important groundwater systems, we used groundwater age (tritium, SF6, 14C) to inform the geologic model and to provide information on groundwater flow through alternating strata of permeable river gravel beds and fine impermeable beds that form an interconnected unconfined–confined aquifer system with complex groundwater flow processes.</p><p>The aquifers are a result of geological processes responding to climate change cycles from cold glacial when sea level was more than 100m below present sea level, to warm interglacial periods with sea level similar to present day. Glacial climate strata are river gravel, sand and silt deposits and include the artesian aquifers. The interglacial strata form the aquicludes and are marine sand, silt, and clay deposits with interbedded estuarine, swamp and coastal fluvial silt, clay, peat and gravel deposits.</p><p>We have re-visited tracer data sampled during the drilling of multi-level observation well in the early 1990s, and collected new samples from these multi-level bores in order to understand in 3D the groundwater recharge sources, groundwater recharge and flow rates, connection to the rivers, and potential groundwater discharge out to sea. Consistently young water (c. 25 years) at depth greater than 100m indicates preferential flow paths, likely related to paleo-river channels. The flow pattern obtained from the water tracer data improves the geologic information from the drill-holes, and fits with information from recent airborne transient electromagnetic (SkyTEM) geophysical surveys.</p>

scholarly journals Spatial structures and directionalities in Monsoonal precipitation over South Asia

2010 ◽  
Vol 17 (5) ◽  
pp. 371-381 ◽  
Author(s):  
N. Malik ◽  
N. Marwan ◽  
J. Kurths
Keyword(s):  
Indian Subcontinent ◽  
Monsoon Season ◽  
Daily Rainfall ◽  
Heavy Rain ◽  
Data Sets ◽  
Spatial Structures ◽  
Break Phase ◽  
Rainfall Events ◽  
Monsoonal Precipitation ◽  
Rain Events

Abstract. Precipitation during the monsoon season over the Indian subcontinent occurs in form of enormously complex spatiotemporal patterns due to the underlying dynamics of atmospheric circulation and varying topography. Employing methods from nonlinear time series analysis, we study spatial structures of the rainfall field during the summer monsoon and identify principle regions where the dynamics of monsoonal rainfall is more coherent or homogenous. Moreover, we estimate the time delay patterns of rain events. Here we present an analysis of two separate high resolution gridded data sets of daily rainfall covering the Indian subcontinent. Using the method of event synchronization (ES), we estimate regions where heavy rain events during monsoon happen in some lag synchronised form. Further using the delay behaviour of rainfall events, we estimate the directionalities related to the progress of such type of rainfall events. The Active (break) phase of a monsoon is characterised by an increase(decrease) of rainfall over certain regions of the Indian subcontinent. We show that our method is able to identify regions of such coherent rainfall activity.

scholarly journals Effect of natural rainfall on the migration characteristics of runoff and sediment on purple soil sloping cropland during different planting stages

2021 ◽  
Author(s):  
Yi Wang ◽  
Jiupai Ni ◽  
Chengsheng Ni ◽  
Sheng Wang ◽  
Deti Xie
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Heavy Rain ◽  
Sediment Concentration ◽  
Purple Soil ◽  
Torrential Rain ◽  
Sediment Yields ◽  
Natural Rainfall ◽  
Sediment Loss ◽  
Rain Events

Abstract Due to the difficulty in monitoring subsurface runoff and sediment migration, their loss loads are still not clear and need further study. This study monitored water and soil loss occurring within experimental field plots for two calendar years under natural rainfall events. The sediment loss load was quantified by considering the corresponding water flow flux and its sediment concentration. The results showed that 60.04% of the runoff and 2.83% of the sediment were lost underground. The annual underground sediment loss reached up to 54.6 kg*ha−1*yr−1. A total of 69.68% of the runoff yield and 67.25% of the sediment yield were produced during the corn planting stage (CPS: March–July). Heavy rain and torrential rain events produced 94.45%, 65.46% of the annual runoff and 94.45%, 76.21% of the sediment yields during the corn-planting stage and summer fallow period (SFP: August–September). The rain frequency, rainfall, and rainfall duration of each planting stage significantly affected the resulting runoff and sediment yield. Measures aimed at the prevention and control of water-soil loss from purple soil sloping land should heavily focus on torrential rain and heavy rain events during the CPS and SFP. This paper aims to provide a practical reference for quantifying the water and soil loss from purple soil sloping cropland.

scholarly journals Export of <sup>134</sup>Cs and <sup>137</sup>Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

2013 ◽  
Vol 10 (2) ◽  
pp. 2767-2790 ◽  
Author(s):  
S. Nagao ◽  
M. Kanamori ◽  
S. Ochiai ◽  
S. Tomihara ◽  
K. Fukushi ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Heavy Rain ◽  
Rain Event ◽  
Normal Flow ◽  
Flow Conditions ◽  
Pulse Input ◽  
Heavy Rain Event ◽  
Coastal Marine ◽  
Rain Events ◽  
Heavy Rains

Abstract. Effects of a heavy rain event on radiocesium export were studied at stations on the Natsui River and the Same River in Fukushima Prefecture, Japan after Typhoon Roke during 21–22 September 2011, six months after the Fukushima Daiichi Nuclear Power Plant accident. Radioactivity of 134Cs and 137Cs in river waters was 0.011–0.098 Bq L−1 at normal flow conditions during July–September in 2011, but it increased to 0.85 Bq L−1 in high flow conditions by heavy rains occurring with the typhoon. The particulate fractions of 134Cs and 137Cs were 21–56% in the normal flow condition, but were close to 100% after the typhoon. These results indicate that the pulse input of radiocesium associated with suspended particles from land to coastal ocean occurred by the heavy rain event. Export flux of 134Cs and 137Cs by the heavy rain accounts for 30–50% of annual radiocesium flux in 2011. Results show that rain events are one factor controlling the transport and dispersion of radiocesium in river watersheds and coastal marine environments.

scholarly journals Improvement in WRF model prediction for heavy rain events over North Sumatra region using satellite data assimilation

2021 ◽  
Vol 893 (1) ◽  
pp. 012040
Author(s):  
Immanuel Jhonson Arizona Saragih ◽  
Huda Abshor Mukhsinin ◽  
Kerista Tarigan ◽  
Marzuki Sinambela ◽  
Marhaposan Situmorang ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Initial Data ◽  
Satellite Data ◽  
Wrf Model ◽  
Heavy Rain ◽  
Convective System ◽  
Large Area ◽  
Weather Forecasts ◽  
Rain Events ◽  
North Sumatra

Abstract Located adjacent to the Indian Ocean and the Malacca Strait as a source of water vapour, and traversed by the Barisan Mountains which raise the air orographically causing high diurnal convective activity over the North Sumatra region. The convective system that was formed can cause heavy rainfall over a large area. Weather Research and Forecasting (WRF) was a numerical weather model used to make objective weather forecasts. To improve the weather forecasts accuracy, especially for predict heavy rain events, needed to improve the output of the WRF model by the assimilation technique to correct the initial data. This research was conducted to compare the output of the WRF model with- and without assimilation on 17 June 2020 and 14 September 2020. Assimilation was carried out using the 3D-Var technique and warm starts mode on three assimilation schemes, i.e. DA-AMSU which used AMSU-A satellite data, DA-MHS which used MHS satellite data, and DA-BOTH which used both AMSU-A and MHS satellite data. Model output verification was carried out using the observational data (AWS, AAWS, and ARG) and GPM-IMERG data. The results showed that the satellite data assimilation corrects the WRF model initial data, so as increasing the accuracy of rainfall predictions. The DA-BOTH scheme provided the best improvement with a final weighted performance score of 0.64.

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