| 1. |
- Singh, V.P., et al.
(författare)
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Kinematic wave modelling of saturated basal flow in a snowpack
- 1997
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Ingår i: Hydrological Processes. - 0885-6087 .- 1099-1085. ; 11:2, s. 177-187
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Tidskriftsartikel (refereegranskat)abstract
- Movement of snowmelt water through a thin saturated layer at the infiltrating base of a snowpack is modelled by applying the kinematic wave theory. Analytical solutions are obtained for flow depth, velocity and discharge assuming that the rate of input to the saturated layer due to vertical percolation is constant. This assumption results in a linear rise and recession of the snowmelt hydrograph. The solutions are extended to the case of time-varying input. An explicit consideration of infiltration leads to a free boundary problem.
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| 2. |
- Singh, V.P., et al.
(författare)
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Kinematic wave modelling of vertical movement of snowmelt water through a snowpack
- 1997
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Ingår i: Hydrological Processes. - 0885-6087 .- 1099-1085. ; 11:2, s. 149-167
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Tidskriftsartikel (refereegranskat)abstract
- Vertical movement of snowmelt water through snowpacks is modelled by applying the kinematic wave theory. Analytical solutions are obtained for moisture flux, particle velocity, time history and velocity of meltwater front and total moisture content for a single melt event assuming that the melt rate is constant. These solutions are extended to the case involving more than one event.
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| 3. |
- Bengtsson, Lars, et al.
(författare)
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Extreme storms in Malmo, Sweden
- 2010
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 24:24, s. 3462-3475
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Tidskriftsartikel (refereegranskat)abstract
- Short-term very intensive storms in the years 1980-2007 from rain gauges in Malmo have been analysed to find intensities of long return periods and to investigate trends. Observations from different stations have been pooled into series to which probability functions have been adjusted. Quality control of short-term precipitation records is emphasized. In order to investigate whether high rain intensities are different today compared to back in time, new and old rain data have been compared. Trends over the last 25 years have been computed for storms of duration 10 min to 1 h, and for 89 years of daily rains. A literature review of investigations of changing rain intensities is presented. It is found that 10- to 25-year long rain series from single stations are too short to give good estimates of storms of long recurrence time because a single event influences much. The largest observed rains in Malmo in the investigated period have a return period of about 20-50 years. For the very short-term storms, 50-year old intensity-duration-frequency curves do not differ much from those derived from new data. Trend analysis shows changing short-term high storm intensities only for storms of 10-min duration. (C) Copyright. 2010 John Wiley & Sons, Ltd.
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| 4. |
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| 5. |
- Bengtsson, Lars, et al.
(författare)
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Long- term change of daily and multi- daily precipitation in southern Sweden
- 2014
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 28:6, s. 2897-2911
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Tidskriftsartikel (refereegranskat)abstract
- Daily rain series from southern Sweden with records dating back to the 1870s have been analysed to investigate the trends of daily and multi-day precipitation of different return periods with emphasis on the extremes. Probabilities of extreme storms were determined as continuously changing values based on 25 years of data. An extra set of data was used to investigate changes in Skane, the southernmost peninsula of Sweden. Another 30-year data set of more than 200 stations of a dense gauge network in Skane was used to investigate the relation between very large daily rainfall and annual precipitation. The annual precipitation has increased significantly all over southern Sweden due to increased winter precipitation. There is a trend of increasing maximum annual daily precipitation at only one station, where the annual maximum often occurs in winter. The number of events with a short return period is increasing, but the number of more extreme events has not increased. Daily and multi-daily design storms of long return periods determined from extreme value analysis with updating year by year are not higher today than during the last 100 years. The largest daily storms are not related to stations with annual rainfall but seem to occur randomly. Copyright (c) 2013 John Wiley & Sons, Ltd.
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| 6. |
- Chen, Haorui, et al.
(författare)
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Forecasting the human and climate impacts on groundwater resources in the irrigated agricultural region of North China Plain
- 2023
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 37:3
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Tidskriftsartikel (refereegranskat)abstract
- Climate change has caused significant impacts on water resource redistribution around the world and posed a great threat in the last several decades due to intensive human activities. The impacts of human water use and management on regional water resources remain unclear as they are intertwined with the impacts of climate change. In this study, we disentangled the impact of climate-induced human activities on groundwater resources in a typical region of the semi-arid North China Plain based on a process-oriented groundwater modelling approach accounting for climate-human-groundwater interactions. We found that the climate-induced human effect is amplified in water resources management ('amplifying effect') for our study region under future climate scenarios. We specifically derived a tipping point for annual precipitation of 350 mm, below which the climate-induced human activities on groundwater withdrawal will cause significant 'amplifying effect' on groundwater depletion. Furthermore, we explored the different pumping scenarios under various climate conditions and investigated the pumping thresholds, which the pumping amount should not exceed (4 x 10(7) m(3)) in order to control future groundwater level depletion. Our results highlight that it is critical to implement adaptive water use practices, such as water-saving irrigation technologies in the semi-arid regions, in order to mitigate the negative impacts of groundwater overexploitation, particularly when annual precipitation is anomalously low.
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| 7. |
- Divine, D. V., et al.
(författare)
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Modelling the regional climate and isotopic composition of Svalbard precipitation using REMOiso : a comparison with available GNIP and ice core data
- 2011
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:24, s. 3748-3759
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Tidskriftsartikel (refereegranskat)abstract
- Simulations of a regional (approx. 50 km resolution) circulation model REMOiso with embedded stable water isotope module covering the period 1958-2001 are compared with the two instrumental climate and four isotope series (d18O) from western Svalbard. We examine the data from ice cores drilled on Svalbard ice caps in 1997 (Lomonosovfonna, 1250 m asl) and 2005 (Holtedahlfonna, 1150 m asl) and the GNIP series from Ny-angstrom lesund and Isfjord Radio. The surface air temperature (SAT) and precipitation data from Longyearbyen and Ny-angstrom lesund are used to assess the skill of the model in reproducing the local climate. The model successfully captures the climate variations on the daily to multidecadal times scales although it tends to systematically underestimate the winter SAT. Analysis suggests that REMOiso performs better at simulating isotope compositions of precipitation in the winter than summer. The simulated and measured Holtedahlfonna d18O series agree reasonably well, whereas no significant correlation has been observed between the modelled and measured Lomonosovfonna ice core isotopic series. It is shown that sporadic nature as well as variability in the amount inherent in precipitation process potentially limits the accuracy of the past SAT reconstruction from the ice core data. This effect in the study area is, however, diminished by the role of other factors controlling d18O in precipitation, most likely sea ice extent, which is directly related with the SAT anomalies.
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| 8. |
- Hiroshiro, Y, et al.
(författare)
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Hydrogeochemical properties of a salinity-affected coastal aquifer in western Japan
- 2006
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 20:6, s. 1425-1435
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Tidskriftsartikel (refereegranskat)abstract
- Coastal groundwater aquifers are often exposed to heavy pumping and consequently to risks of saltwater intrusion. In many cases, however, the observed increase in groundwater salinity can only be partly explained by actual saltwater intrusion from the sea. Other salinity-increasing processes may also significantly contribute to the total salt content of the groundwater. This paper describes a geochemical investigation that was carried out to investigate recent salinity increases in groundwater for the Motooka coastal area in Fukuoka, Japan. A strong increase in electrical conductivity at 15-20 m depth was observed, corresponding to the freshwater and saltwater interface. Oxidation-reduction potentials observed in deeper groundwater were low, indicating long residence time for the groundwater. These results, together with hydrogen-oxygen isotope ratio analysis, indicated that the deeper groundwater is affected by seawater. Consequently, observed tritium concentration in the shallow groundwater system was higher than that of the deeper groundwater system, and a C-14 isotope dating of shell samples collected at 2 m depth indicated an age of about 2000 years. The overall results suggest that the aquifer was originally below the current sea floor and that deeper saline groundwater is not mixed with the shallower fresh groundwater. The deeper groundwater is, therefore, mainly affected by old seawater. In other words, modern saltwater intrusion has not yet occurred even if some wells contain saline water. The study shows that, even though coastal aquifers are heavily pumped, the reason for the rise in groundwater salinity may not necessarily be due to seawater intrusion. Further geochemical and hydrological investigations will be necessary to identify the underlying mechanisms. Copyright (c) 2006 John Wiley & Sons, Ltd.
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| 9. |
- Jin, Y H, et al.
(författare)
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Detection of ENSO-influence on the monthly precipitation in South Korea
- 2005
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 19:20, s. 4081-4092
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Tidskriftsartikel (refereegranskat)abstract
- During the latest several decades, there has been considerable interest in revealing the relationship between El Nino-southern oscillation (ENSO) and hydro-meteorological variables. The oscillation is characterized by a simple index, the southern oscillation index (SOI). However, thus far, there is little evidence for the influence of ENSO in Korea and Japan. The influence of ENSO has also been studied in South Korea, but the estimated results are still qualitative and show an indirect relationship between ENSO and hydro-meteorological variables. In this study we use simple approaches to reveal the quantitative and direct correlation between SOI and the monthly precipitation at five stations distributed over South Korea. The monthly precipitation data are transformed into nonexceedance probability time series because the data cannot be normally distributed by applying the usual transformations. The SOI is classified into five categories according to their values. Additionally, to detect the nonlinear relationship between categorized SOI and nonexceedance probability of the monthly precipitation, we use Kendall's tau, a nonparametric test. Significant correlations between the categorized SOI and the transformed precipitation are detected. Generally, the monthly precipitation is influenced by a La Nina event with a lag time of 4 months for southern coastal areas and a lag time of 5 months for middle to high regions in South Korea.
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| 10. |
- Mendoza, Jose Alfredo, et al.
(författare)
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Aquifer interactions with a polluted mountain river of Nicaragua
- 2008
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 22:13, s. 2264-2273
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between a stream and nearby shallow aquifers were investigated in a mountain basin being polluted by mercury released during mining in central Nicaragua. Hourly data series of water levels and temperatures were analysed using cross-correlation. Resistivity imaging was used to map the subsurface and to complement the hydrological data interpretation. The results show the complex hydrogeological conditions that characterize the region, with weathering and fractured rock as main contributors to groundwater transport. The resistivity images suggest the presence of two vertical dykes perpendicular to the stream, and zones rich in clay. The data series indicate a rapid response from the aquifers to recharge events, followed by immediate discharge on a yearly basis. Furthermore, alternating periods of stream infiltration and aquifer discharge were identified. This work demonstrates that surface water pollution is a threat to groundwater quality in the area.
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