scholarly journals Seasonal changes of the soil hydrological and erosive response in contrasted Mediterranean eco-geomorphological conditions at patch scale

2013 ◽  
Vol 5 (2) ◽  
pp. 1423-1460 ◽  
Author(s):  
M. A. Gabarrón-Galeote ◽  
J. F. Martínez-Murillo ◽  
M. A. Quesada ◽  
J. D. Ruiz-Sinoga
Keyword(s):  
Soil Water ◽  
Seasonal Changes ◽  
Overland Flow ◽  
Hydrological Response ◽  
The South ◽  
Seasonal Behavior ◽  
Maximum Rainfall ◽  
Small Catchment ◽  
The North ◽  
Mediterranean Areas

Abstract. Mediterranean areas are characterized by a strong spatial variability that makes highly complex the soil hydrological response. Moreover, Mediterranean climate has a marked seasonal variability that provokes dramatic changes on the soil properties determining the hydrological behavior, such as soil water content, crust formation or soil water repellency (SWR). Thus, soil hydrological and erosive response in Mediterranean areas can be highly time- as well space-dependant. The main goal of this study was to characterize the relations between SWR, aspect and vegetation, determining the soil hydrological and erosive response throughout the rainy period in different microenvironments of opposite hillslopes. This study was undertaken in a small catchment located in the South of Spain. Erosion plots were installed in the north- and the south-facing hillslope, in areas with different vegetal cover, and runoff and sediments were collected. Moreover, precipitation parameters were recorded and SWR measurements were performed. SWR proved to have a significant effect on the soil hydrological response, but this influence was modulated by seasonal changes and by the discontinuities on the repellent layer. In general, the influence of SWR was restricted to the first rains after the summer and was greater on the north-facing hillslope due to the more continuous vegetation cover. The more important precipitation parameter influencing runoff generated was maximum rainfall intensity in ten minutes (Imax). The relation between Imax and overland flow showed a contrasting seasonal behavior in the north-facing hillslope and, on the contrary, remained homogeneous throughout the year in the south-facing hillslope.

scholarly journals Seasonal changes in the soil hydrological and erosive response depending on aspect, vegetation type and soil water repellency in different Mediterranean microenvironments

Solid Earth ◽  
2013 ◽  
Vol 4 (2) ◽  
pp. 497-509 ◽  
Author(s):  
M. A. Gabarrón-Galeote ◽  
J. F. Martínez-Murillo ◽  
M. A. Quesada ◽  
J. D. Ruiz-Sinoga
Keyword(s):  
Soil Water ◽  
Vegetation Type ◽  
Water Repellency ◽  
Vegetation Pattern ◽  
The South ◽  
Wet Season ◽  
Soil Water Repellency ◽  
The North ◽  
Mediterranean Areas ◽  
Set Up

Abstract. Mediterranean areas are characterized by a strong spatial variability that makes the soil hydrological response highly complex. Moreover, Mediterranean climate has marked seasons that provoke dramatic changes on soil properties determining the runoff rates, such as soil water content or soil water repellency (SWR). Thus, soil hydrological and erosive response in Mediterranean areas can be highly time- as well as space-dependant. This study shows SWR, aspect and vegetation as factors of the soil hydrological and erosive response. Erosion plots were set up in the north- and the south-facing hillslope and rainfall, runoff, sediments and SWR were monitored. Soil water repellency showed a seasonal behaviour and it was presented in three out of four microenvironments after the summer, disappearing in the wet season. In general, runoff rate was higher in shrubs patches (0.47 ± 0.67 mm) than in inter-shrub soils (1.54 ± 2.14 mm), but it changed seasonally in different ways, depending on the aspect considered, decreasing in the north-facing hillslope and increasing in the south-facing one. The main factor determining the hydrological and erosive response was the rainfall intensity, regardless of the rainfall depth of the event. This response was modulated mainly by SWR in the north-facing hillslope and the vegetation pattern in the south-facing one.

scholarly journals Assessment of the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) as an Agricultural Drought Index in China

2018 ◽  
Vol 10 (8) ◽  
pp. 1302 ◽  
Author(s):  
Jueying Bai ◽  
Qian Cui ◽  
Deqing Chen ◽  
Haiwei Yu ◽  
Xudong Mao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
Microwave Remote Sensing ◽  
Agricultural Drought ◽  
Drought Monitoring ◽  
In Situ Observation ◽  
Soil Water Deficit ◽  
The South ◽  
The North

China is frequently subjected to local and regional drought disasters, and thus, drought monitoring is vital. Drought assessments based on available surface soil moisture (SM) can account for soil water deficit directly. Microwave remote sensing techniques enable the estimation of global SM with a high temporal resolution. At present, the evaluation of Soil Moisture Active Passive (SMAP) SM products is inadequate, and L-band microwave data have not been applied to agricultural drought monitoring throughout China. In this study, first, we provide a pivotal evaluation of the SMAP L3 radiometer-derived SM product using in situ observation data throughout China, to assist in subsequent drought assessment, and then the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) is compared with the atmospheric water deficit (AWD) and vegetation health index (VHI). It is found that the SMAP can obtain SM with relatively high accuracy and the SWDI-SMAP has a good overall performance on drought monitoring. Relatively good performance of SWDI-SMAP is shown, except in some mountain regions; the SWDI-SMAP generally performs better in the north than in the south for less dry bias, although better performance of SMAP SM based on the R is shown in the south than in the north; differences between the SWDI-SMAP and VHI are mainly shown in areas without vegetation or those containing drought-resistant plants. In summary, the SWDI-SMAP shows great application potential in drought monitoring.

scholarly journals Flood Risk Zoning by Using 2D Hydrodynamic Modeling: A Case Study in Jinan City

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Tao Cheng ◽  
Zongxue Xu ◽  
Siyang Hong ◽  
Sulin Song
Keyword(s):  
Flood Risk ◽  
Flood Control ◽  
Overland Flow ◽  
The South ◽  
Rapid Urbanization ◽  
Risk Zoning ◽  
The North ◽  
Hourly Rainfall ◽  
Infoworks Icm ◽  
Jinan City

Climate change and rapid urbanization have aggravated the rainstorm flood in Jinan City during the past decades. Jinan City is higher in the south and lower in the north with a steep slope inclined from the south to the north. This results in high-velocity overland flow and deep waterlogging, which poses a tremendous threat to pedestrians and vehicles. Therefore, it is vital to investigate the rainstorm flood and further perform flood risk zoning. This study is carried out in the “Sponge City Construction” pilot area of Jinan City, where the InfoWorks ICM 2D hydrodynamic model is utilized for simulating historical and designed rainfall events. The model is validated with observations, and the causes for errors are analyzed. The simulated water depth and flow velocity are recorded for flood risk zoning. The result shows that the InfoWorks ICM 2D model performed well. The flood risk zoning result shows that rainfalls with larger recurrence intervals generate larger areas of moderate to extreme risk. Meanwhile, the zoning results for the two historical rainfalls show that flood with a higher maximum hourly rainfall intensity is more serious. This study will provide scientific support for the flood control and disaster reduction in Jinan City.

Predicting stormflow response of a degraded tropical grassland catchment using a spatially variable infiltration model

2021 ◽  
Author(s):  
Zhuo Cheng ◽  
Jun Zhang ◽  
Bofu Yu ◽  
L. Adrian Bruijnzeel
Keyword(s):  
Rainfall Intensity ◽  
Overland Flow ◽  
Stream Water ◽  
Catchment Scale ◽  
Infiltration Capacity ◽  
Maximum Rainfall ◽  
Small Catchment ◽  
Near Surface ◽  
Infiltration Model ◽  
Infiltration Rates

<p>Reduced surface infiltration capacity (K<sub>sat</sub>), increased infiltration-excess overland flow (IOF) and soil loss after deforestation and subsequent surface degradation in the humid tropics are well-documented. However, attempts to predict concomitant increases in storm runoff using physically-based approaches or to relate infiltration model parameter values calibrated with observed hyetographs and hydrographs at the small catchment scale to point-based measurements of K<sub>sat</sub> are rare. We used measured rainfall intensity and stormflow rates at 5-min intervals for 37 separate events (receiving 5–154 mm of rain) from the 3.2 ha degraded fire-climax grassland Basper catchment (Leyte Island, Philippines) to evaluate the performance of a spatially variable infiltration (SVI) model. SVI relates actual infiltration rates to rainfall intensity and a spatially averaged infiltration parameter I<sub>m</sub> after an initial infiltration amount F<sub>0</sub> and has been used successfully to predict IOF at the plot scale at various tropical locations. Quickflow hydrographs were produced using the Hewlett & Hibbert straight-line separation method and actual infiltration rates were derived by subtracting 5-min quickflow rates from corresponding rainfall inputs. SVI-predicted actual infiltration rates were compared with observed rates to derive optimized values of I<sub>m</sub> and F<sub>0</sub> per event. Earlier work at Basper had revealed very low (near-)surface values of K<sub>sat</sub> (implying frequent IOF although there was reason to suspect that K<sub>sat</sub> was underestimated). No explicit measurement was made of hillslope IOF, but stable isotope mass balance computations and a high degree of stream-water dilution during times of rain suggested large contributions of ‘new’ water of low electrical conductivity that likely represented OF. Whilst SVI generally replicated individual quickflow hydrographs very well, values of I<sub>m</sub> and F<sub>0</sub> varied markedly between events. Using the median values of I<sub>m</sub> (46 mm h<sup>-1</sup>) and F<sub>0</sub> (6.8 mm) produced reasonable to good results (NSE > 0.6) for a subset of 15 (larger) events only. F<sub>0</sub> was positively related to maximum rainfall intensity over 15 or 30 min while I<sub>m</sub> was not significantly correlated to measured (mid-slope) soil water content or precipitation-based antecedent wetness indicators. However, I<sub>m</sub> exhibited a significant inverse correlation (Spearman r<sub>s</sub>=-0.617) with pre-storm baseflow rate Q<sub>b</sub> (notably for Q<sub>b</sub><0.5 mm d<sup>-1</sup>) suggesting foot-slope wetness status may be important for stormflow generation as well. The spatial distribution of K<sub>sat</sub>-values implied by SVI confirmed the suspected under-estimation of field-based K<sub>sat</sub> across the measured range, presumably reflecting a combination of macropore smearing (near-surface Amoozemeter measurements) and the limited size of the double-ring infiltrometer used for the measurement of surface infiltration rates.</p>

Runoff variability of an extreme flash flood event on the Catalan Coastal System-Ebro Basin water divide (NE Iberian Peninsula)

2020 ◽  
Author(s):  
Josep Carles Balasch ◽  
Jordi Tuset ◽  
Xavier Castelltort ◽  
Mariano Barriendos ◽  
Llanos Valera-Prieto ◽  
...  
Keyword(s):  
Soil Moisture ◽  
River Basin ◽  
Overland Flow ◽  
Peak Flow ◽  
Flash Flood ◽  
Maximum Intensity ◽  
Tree Cover ◽  
Hydrological Response ◽  
Coastal System ◽  
Maximum Rainfall

<p>On the 22<sup>nd</sup> and 23<sup>rd</sup> of October 2019 a severe rainfall produced floods in the basins of the Catalan Coastal Range-Ebro Depression border (Francolí, Set, Femosa rivers) that affected various towns such as L'Espluga de Francolí, Montblanc, l'Albi, Vinaixa, among others, causing 6 deaths and material damages that exceeded 100 million euros. According to historical records, this rainfall episode would exceed the maximum rainfall estimates expected for 500 years in this region and the maximum heights reached by the water are comparable to, or exceed, those of the remembered Santa Tecla flash flood on September 1874, which would have a recurrence of more than 250 years.</p><p>This rain was caused by a S-SE warm and wet Mediterranean air mass over the Catalan Coastal System (Prades and Llena Ranges). The area of maximum rainfall was located at the headwaters of the rivers Set, Francolí and Montsant rivers, with rain depths above 200 mm. The hourly distribution at El Vilosell and Prades rain gauges shows 50 mm from 6 to 14 UTC and maximum intensity of 10 to 15 mm h<sup>-1</sup>, followed by a second pulse of 180-220 mm from 16 to 01 UTC and maximum intensity of 65 mm h<sup>-1</sup> (maximum 3.1 mm min<sup>-1</sup>). </p><p>Soil moisture content was low at the time of the rain after a dry summer. Early precipitation saturated the topsoil, therefore the soil surface was very wet at the beginning of the second rainfall event and it generated a hortonian overland flow. The highest rainfall intensity occurred around 19 UTC and the peak flow response was immediate, around an hour later, depending on the location.</p><p>Despite the similarity of rainfall and initial soil moisture conditions, the hydrological response in the two analyzed basins was markedly different. The flows generated in the Set River basin at l'Albagès reservoir produced a peak flow of 245 m<sup>3</sup> s<sup>-1</sup> (1.5·m<sup>3</sup>·s<sup>-1</sup>·km<sup>-2</sup>) and a very low flood runoff ratio of only 8%. In the basin of the Francolí River, at L'Espluga de Francolí, the peak flow was 1,300 m<sup>3</sup> s<sup>-1</sup> (13 m<sup>3</sup>·s<sup>-1</sup>·km<sup>-2</sup>) and the runoff ratio was of the order of 70%. The Set river basin is basically agricultural with terraced slopes that retained much of the precipitation, only released after the flood as baseflow. The Francolí river basin has steeper slopes and channels and is dominated by an extensive tree cover but very poorer soils that caused little water retention, giving rise to a major hydrological response, an order of magnitude larger than that of the Set River.</p>

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

US and Russian policies and strategies in the Middle East: Iraq and Syria as a model

2019 ◽  
pp. 220
Author(s):  
Esraa Aladdin Noori ◽  
Nasser Zain AlAbidine Ahmed
Keyword(s):  
Middle East ◽  
East Asia ◽  
Balance Of Power ◽  
Western World ◽  
International Conflicts ◽  
The South ◽  
The West ◽  
The North ◽  
East Region ◽  
Middle East Region

The Russian-American relations have undergone many stages of conflict and competition over cooperation that have left their mark on the international balance of power in the Middle East. The Iraqi and Syrian crises are a detailed development in the Middle East region. The Middle East region has allowed some regional and international conflicts to intensify, with the expansion of the geopolitical circle, which, if applied strategically to the Middle East region, covers the area between Afghanistan and East Asia, From the north to the Maghreb to the west and to the Sudan and the Greater Sahara to the south, its strategic importance will seem clear. It is the main lifeline of the Western world.

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

Observed seasonal regimes of North-South Atlantic Ocean interbasin exchange

2019 ◽  
Author(s):  
Hamed D. Ibrahim
Keyword(s):  
North Atlantic ◽  
Climate Models ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Volume Flux ◽  
The South ◽  
The North ◽  
Basin Scale ◽  
Interbasin Exchange ◽  
North And South

North and South Atlantic lateral volume exchange is a key component of the Atlantic Meridional Overturning Circulation (AMOC) embedded in Earth’s climate. Northward AMOC heat transport within this exchange mitigates the large heat loss to the atmosphere in the northern North Atlantic. Because of inadequate climate data, observational basin-scale studies of net interbasin exchange between the North and South Atlantic have been limited. Here ten independent climate datasets, five satellite-derived and five analyses, are synthesized to show that North and South Atlantic climatological net lateral volume exchange is partitioned into two seasonal regimes. From late-May to late-November, net lateral volume flux is from the North to the South Atlantic; whereas from late-November to late-May, net lateral volume flux is from the South to the North Atlantic. This climatological characterization offers a framework for assessing seasonal variations in these basins and provides a constraint for climate models that simulate AMOC dynamics.

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