| 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. |
- Singh, P, et al.
(författare)
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Hydrological sensitivity of a large Himalayan basin to climate change
- 2004
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Ingår i: Hydrological Processes. - : Wiley. - 1099-1085 .- 0885-6087. ; 18:13, s. 2363-2385
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Tidskriftsartikel (refereegranskat)abstract
- The present study sets out to investigate the sensitivity of water availability to climate change for a large western Himalayan river (the Satluj River basin with an area of 22 275 km(2) and elevation range of 500 to 7000 m), which receives contributions from rain, snow and glacier melt runoff. About 65% of the basin area is covered with snow during winter, which reduces to about 11% after the ablation period. After having calibrated a conceptual hydrological model to provide accurate simulations of observed stream flow, the hydrological response of the basin was simulated using different climatic scenarios over a period of 9 years. Adopted plausible climate scenarios included three temperature scenarios (T + 1, T + 2, T + 3degreesC) and four rainfall scenarios (P - 10, P - 5, P + 5 and P + 10%). The effect of climate change was studied on snowmelt and rainfall contribution runoff, and total stream flow. Under warmer climate, a typical feature of the study basin was found to be reduction in melt from the lower part of the basin owing to a reduction in snow covered area and shortening of the summer melting season, and, in contrast, an increase in the melt from the glacierized part owing to larger melt and an extended ablation period. Thus, on the basin scale, reduction in melt from the lower part was counteracted by the increase from melt from upper part of the basin, resulting in a decrease in the magnitude of change in annual melt runoff. The impact of climate change was found to be more prominent on seasonal rather than annual water availability. Reduction of water availability during the summer period, which contributes about 60% to the annual flow, may have severe implications on the water resources of the region, because demand of water for irrigation, hydropower and other usage is at its peak at this time. Copyright (C) 2004 John Wiley Sons, Ltd.
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| 7. |
- Semadeni Davies, Annette, et al.
(författare)
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The water balance of a sub-Arctic town
- 1999
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Ingår i: Hydrological Processes. - 1099-1085. ; 13:12-13, s. 1871-1885
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Tidskriftsartikel (refereegranskat)abstract
- Urban water balances differ from their rural counterparts due to extreme spatial heterogeneity, water imported from outside catchment boundaries and changed flow paths (e.g., drainage pipes and impervious surfaces). Urban catchments are characterized by increased peak discharges and fast response times, each contributing to specific environmental problems. The water balances of towns in the northern high latitudes are further complicated by snow which represents an energy dependent seasonal water store. This paper investigates the monthly water balance of Lulea (June 1992 to June 1996), a Swedish town of 71 000 inhabitants 100 km south of the Arctic Circle. The town has snow cover for five to six months of the year and thaw is usually in late April. Data available included daily precipitation, temperature and inflow to the Uddebo waste water treatment plant; and monthly potential evapotranspiration, groundwater levels and water supply statistics. Of interest were the seasonal differences in runoff volumes and flow pathways to the waste water treatment plant and receiving waters. It was found that increased volumes of runoff, reduced concentration times and long duration led to flooding and high waste water loads at the treatment plant. The surface water component of sewage originates from direct flow into pipe inlets and infiltration into sewer pipes. Autumn and spring were found to be the periods of groundwater recharge, although frozen soil can limit water percolation. Copyright (C) 1999 John Wiley & Sons, Ltd.
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| 8. |
- Bobba, A. G., et al.
(författare)
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Application of a watershed runoff model to north-east pond river, Newfoundland: To study water balance and hydrological characteristics owing to atmospheric change
- 1997
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Ingår i: Hydrological Processes. - 1099-1085. ; 11:12, s. 1573-1593
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Tidskriftsartikel (refereegranskat)abstract
- The hydrological sensitivities to long-term climate change of a watershed in Eastern Canada were analysed using a deterministic watershed runoff model developed to simulate watershed acidification. This model was modified to study atmospheric change effects in the watershed. Water balance modelling techniques, modified for assessing climate effects, were developed and tested for a watershed using atmospheric change scenarios from both state of the art general circulation models and a series of hypothetical scenarios. The model computed daily surface, inter- and groundwater hows from the watershed. The moisture, infiltration and recharge rate are also computed in the soil reservoirs. The thirty years of simulated data can be used to evaluate the effects of climatic change on soil moisture, recharge rate and surface and subsurface flow systems. The interaction between surface and subsurface water is discussed in relation to climate change. These hydrological results raise the possibility of major environmental and socioeconomic difficulties and have significant implications for future water resource planning and management. (C) 1997 John Wiley & Sons, Ltd.
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| 9. |
- Bengtsson, Lars
(författare)
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Probability of combined high sea levels and large rains in Malmö, Sweden, southern Öresund
- 2016
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087. ; 30:18, s. 3172-3183
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Tidskriftsartikel (refereegranskat)abstract
- Observations of sea level and precipitation in Malmö, Sweden in the southeastern part of the sound Öresund have been used to estimate the probabilities of local compound events of high sea level and large daily and hourly rains. There are observations of sea level and daily rains extending back to 1930. The observations of short-term rainfall are from 1980 and onwards. Most large rainfalls come in the summer, while the highest sea levels are in the autumn and in the winter. The highest observed sea level is about 130cm above mean sea level, and the largest daily rain is close to 100mm. However, the highest sea level observed during a day with rainfall corresponding to the 1-year rain is less than 60cm. The highest sea level observed during an hour with 1-year hourly rainfall is 30cm. From the statistics of daily rains, hourly rains and sea level, extreme values for each of them have been computed. For events with frequency higher than one per four years the probabilities of combined events sea level - rainfall are determined directly from the observations. For more rare events, marginal distributions of sea level and rainfall are determined. Copulas and conditional probabilities are used. When the sea level exceeds 20cm above mean sea level, daily rains exceeding 10mm are almost independent of the sea level and so are hourly rains exceeding 5mm. It is extremely rare that large rains occur when the sea level is very high. The combination of 1-year rainfall and the 1-year sea level has a return period of more than 200years.
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