scholarly journals Scenario approach for the seasonal forecast of Kharif flows from Upper Indus Basin

2017 ◽  
Author(s):  
Muhammad Fraz Ismail ◽  
Wolfgang Bogacki
Keyword(s):  
Water Availability ◽  
Indus Basin ◽  
Flow Volume ◽  
Seasonal Forecasts ◽  
Important Indicator ◽  
Upper Indus Basin ◽  
Ice Melt ◽  
Degree Day ◽  
Snow And Ice Melt ◽  
Snow And Ice

Abstract. Snow and glacial melt runoff are the major sources of water contribution from the high mountainous terrain of Indus river upstream of the Tarbela reservoir. A reliable forecast of seasonal water availability for the Kharif cropping season (April–September) can pave the way towards the better water management and subsequently boost the agro-economy of Pakistan. The use of degree-day models in conjunction with the satellite based remote sensing data for the forecasting of seasonal snow and ice melt runoff has proved to be a suitable approach for the data scarce regions. In the present research, Snowmelt Runoff Model (SRM) has not only been enhanced by incorporating the “glacier (G)” component but also applied for the forecast of seasonal water availability from the Upper Indus Basin (UIB). Excel based SRM + G takes into account of separate degree-day factors for snow and ice melt processes. The UIB has been divided into Upper and Lower part because of the different climatic conditions in the Tibetan plateau. The application of seasonal scenario based approach proved to be very adequate for long term water availability forecast. The comparison between different models of operational seasonal forecasts for the UIB for the period in consideration show that SRM + G tends to slightly underestimate the flow volume on average by about 2 % with an overall mean absolute error MAE of 9.6 %, while the two other approaches overestimate the Kharif flow volume on average by about 6 %. More important, the standard deviation of SRM + G forecast errors is 5.7 % only, which is an important indicator for the forecasting skill.

scholarly journals Scenario approach for the seasonal forecast of Kharif flows from the Upper Indus Basin

2018 ◽  
Vol 22 (2) ◽  
pp. 1391-1409 ◽  
Author(s):  
Muhammad Fraz Ismail ◽  
Wolfgang Bogacki
Keyword(s):  
Water Availability ◽  
Climatic Conditions ◽  
Indus Basin ◽  
Percentage Error ◽  
The Tibetan Plateau ◽  
Streamflow Prediction ◽  
Component Distribution ◽  
Upper Indus Basin ◽  
Degree Day ◽  
Scenario Approach

Abstract. Snow and glacial melt runoff are the major sources of water contribution from the high mountainous terrain of the Indus River upstream of the Tarbela reservoir. A reliable forecast of seasonal water availability for the Kharif cropping season (April–September) can pave the way towards better water management and a subsequent boost in the agro-economy of Pakistan. The use of degree-day models in conjunction with satellite-based remote-sensing data for the forecasting of seasonal snow and ice melt runoff has proved to be a suitable approach for data-scarce regions. In the present research, the Snowmelt Runoff Model (SRM) has not only been enhanced by incorporating the glacier (G) component but also applied for the forecast of seasonal water availability from the Upper Indus Basin (UIB). Excel-based SRM+G takes account of separate degree-day factors for snow and glacier melt processes. All-year simulation runs with SRM+G for the period 2003–2014 result in an average flow component distribution of 53, 21, and 26 % for snow, glacier, and rain, respectively. The UIB has been divided into Upper and Lower parts because of the different climatic conditions in the Tibetan Plateau. The scenario approach for seasonal forecasting, which like the Ensemble Streamflow Prediction method uses historic meteorology as model forcings, has proven to be adequate for long-term water availability forecasts. The accuracy of the forecast with a mean absolute percentage error (MAPE) of 9.5 % could be slightly improved compared to two existing operational forecasts for the UIB, and the bias could be reduced to −2.0 %. However, the association between forecasts and observations as well as the skill in predicting extreme conditions is rather weak for all three models, which motivates further research on the selection of a subset of ensemble members according to forecasted seasonal anomalies.

scholarly journals A snow and ice melt seasonal prediction modelling system for Alpine reservoirs

2016 ◽  
Vol 374 ◽  
pp. 143-150 ◽  
Author(s):  
Kristian Förster ◽  
Felix Oesterle ◽  
Florian Hanzer ◽  
Johannes Schöber ◽  
Matthias Huttenlau ◽  
...  
Keyword(s):  
Snow Water Equivalent ◽  
Seasonal Prediction ◽  
Seasonal Forecasts ◽  
Time Step ◽  
Small Catchment ◽  
Ice Melt ◽  
Prediction Modelling ◽  
Modelling System ◽  
Snow And Ice Melt ◽  
Snow And Ice

Abstract. The timing and the volume of snow and ice melt in Alpine catchments are crucial for management operations of reservoirs and hydropower generation. Moreover, a sustainable reservoir operation through reservoir storage and flow control as part of flood risk management is important for downstream communities. Forecast systems typically provide predictions for a few days in advance. Reservoir operators would benefit if lead times could be extended in order to optimise the reservoir management. Current seasonal prediction products such as the NCEP (National Centers for Environmental Prediction) Climate Forecast System version 2 (CFSv2) enable seasonal forecasts up to nine months in advance, with of course decreasing accuracy as lead-time increases. We present a coupled seasonal prediction modelling system that runs at monthly time steps for a small catchment in the Austrian Alps (Gepatschalm). Meteorological forecasts are obtained from the CFSv2 model. Subsequently, these data are downscaled to the Alpine Water balance And Runoff Estimation model AWARE running at monthly time step. Initial conditions are obtained using the physically based, hydro-climatological snow model AMUNDSEN that predicts hourly fields of snow water equivalent and snowmelt at a regular grid with 50 m spacing. Reservoir inflow is calculated taking into account various runs of the CFSv2 model. These simulations are compared with observed inflow volumes for the melting and accumulation period 2015.

scholarly journals Evaluating the impact of climate on snow- and ice-melt dynamics in the Taillon basin, French Pyrénées

1997 ◽  
Vol 43 (145) ◽  
pp. 563-568 ◽  
Author(s):  
David M. Hannah ◽  
Glenn R. McGregor
Keyword(s):  
Large Scale ◽  
Energy Budgets ◽  
Computer Assisted ◽  
Air Masses ◽  
Atmospheric Circulation Patterns ◽  
Ice Melt ◽  
Circulation Types ◽  
The Impact ◽  
Snow And Ice Melt ◽  
Snow And Ice

AbstractThis pilot study adopts a computer-assisted synoptic typing methodology to evaluate the totality of climatic influences on snow- and ice-melt dynamics within a small cirque basin in the French Pyrénées. The synoptic categories identified possess contrasting large-scale atmospheric circulation patterns and surface energy budgets which generate differential ablation responses. Continental air masses yield consistently high melt. Advection of moist maritime air also produces elevated but more variable ablation due to air-mass transitions. The two observed local valley circulation types show melt to be higher under nocturnal katabatic drainage than for anabatic wind flows associated with development of daytime ridge-top cumulus.

The variability of the snow and ice melt in alpine rivers in northwestern China

2014 ◽  
Vol 11 (4) ◽  
pp. 884-895 ◽  
Author(s):  
Chang-bin Li ◽  
Jia-guo Qi ◽  
Lin-shan Yang ◽  
Wen-jin Yang ◽  
Gao-feng Zhu ◽  
...  
Keyword(s):  
Northwestern China ◽  
Ice Melt ◽  
Alpine Rivers ◽  
Snow And Ice Melt ◽  
Snow And Ice

scholarly journals Prevailing climatic trends and runoff response from Hindukush–Karakoram–Himalaya, upper Indus basin

2015 ◽  
Vol 6 (1) ◽  
pp. 579-653 ◽  
Author(s):  
S. Hasson ◽  
J. Böhner ◽  
V. Lucarini
Keyword(s):  
High Altitude ◽  
Water Availability ◽  
Winter Season ◽  
Indus Basin ◽  
Climatic Trend ◽  
Upper Indus Basin ◽  
Climatic Trends ◽  
Mixed Response ◽  
Long Term Trends

Abstract. Largely depending on meltwater from the Hindukush–Karakoram–Himalaya, withdrawals from the upper Indus basin (UIB) contribute to half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, we present a comprehensive hydro-climatic trend analysis over the UIB, including for the first time observations from high-altitude automated weather stations. We analyze trends in maximum, minimum and mean temperatures (Tx, Tn, and Tavg, respectively), diurnal temperature range (DTR) and precipitation from 18 stations (1250–4500 m a.s.l.) for their overlapping period of record (1995–2012), and separately, from six stations of their long term record (1961–2012). We apply Mann–Kendall test on serially independent time series to assess existence of a trend while true slope is estimated using Sen's slope method. Further, we statistically assess the spatial scale (field) significance of local climatic trends within ten identified sub-regions of UIB and analyze whether the spatially significant (field significant) climatic trends qualitatively agree with a trend in discharge out of corresponding sub-region. Over the recent period (1995–2012), we find a well agreed and mostly field significant cooling (warming) during monsoon season i.e. July–October (March–May and November), which is higher in magnitude relative to long term trends (1961–2012). We also find general cooling in Tx and a mixed response in Tavg during the winter season and a year round decrease in DTR, which are in direct contrast to their long term trends. The observed decrease in DTR is stronger and more significant at high altitude stations (above 2200 m a.s.l.), and mostly due to higher cooling in Tx than in Tn. Moreover, we find a field significant decrease (increase) in late-monsoonal precipitation for lower (higher) latitudinal regions of Himalayas (Karakoram and Hindukush), whereas an increase in winter precipitation for Hindukush, western- and whole Karakoram, UIB-Central, UIB-West, UIB-West-upper and whole UIB regions. We find a spring warming (field significant in March) and drying (except for Karakoram and its sub-regions), and subsequent rise in early-melt season flows. Such early melt response together with effective cooling during monsoon period subsequently resulted in a substantial drop (weaker increase) in discharge out of higher (lower) latitudinal regions (Himalaya and UIB-West-lower) during late-melt season, particularly during July. These discharge tendencies qualitatively differ to their long term trends for all regions, except for UIB-West-upper, western-Karakorum and Astore. The observed hydroclimatic trends, being driven by certain changes in the monsoonal system and westerly disturbances, indicate dominance (suppression) of nival (glacial) runoff regime, altering substantially the overall hydrology of UIB in future. These findings largely contribute to address the hydroclimatic explanation of the "Karakoram Anomaly".

scholarly journals Prevailing climatic trends and runoff response from Hindukush–Karakoram–Himalaya, upper Indus Basin

2017 ◽  
Vol 8 (2) ◽  
pp. 337-355 ◽  
Author(s):  
Shabeh Hasson ◽  
Jürgen Böhner ◽  
Valerio Lucarini
Keyword(s):  
Water Availability ◽  
Production Systems ◽  
Kendall Test ◽  
Indus Basin ◽  
Monsoon Period ◽  
Upper Indus Basin ◽  
Climatic Trends ◽  
Domestic Use ◽  
Long Term Trends

Abstract. Largely depending on the meltwater from the Hindukush–Karakoram–Himalaya, withdrawals from the upper Indus Basin (UIB) contribute half of the surface water availability in Pakistan, indispensable for agricultural production systems, industrial and domestic use, and hydropower generation. Despite such importance, a comprehensive assessment of prevailing state of relevant climatic variables determining the water availability is largely missing. Against this background, this study assesses the trends in maximum, minimum and mean temperatures, diurnal temperature range and precipitation from 18 stations (1250–4500 m a.s.l.) for their overlapping period of record (1995–2012) and, separately, from six stations of their long-term record (1961–2012). For this, a Mann–Kendall test on serially independent time series is applied to detect the existence of a trend, while its true slope is estimated using the Sen's slope method. Further, locally identified climatic trends are statistically assessed for their spatial-scale significance within 10 identified subregions of the UIB, and the spatially (field-) significant climatic trends are then qualitatively compared with the trends in discharge out of corresponding subregions. Over the recent period (1995–2012), we find warming and drying of spring (field-significant in March) and increasing early melt season discharge from most of the subregions, likely due to a rapid snowmelt. In stark contrast, most of the subregions feature a field-significant cooling within the monsoon period (particularly in July and September), which coincides well with the main glacier melt season. Hence, a decreasing or weakly increasing discharge is observed from the corresponding subregions during mid- to late melt season (particularly in July). Such tendencies, being largely consistent with the long-term trends (1961–2012), most likely indicate dominance of the nival but suppression of the glacial melt regime, altering overall hydrology of the UIB in future. These findings, though constrained by sparse and short observations, largely contribute in understanding the UIB melt runoff dynamics and address the hydroclimatic explanation of the Karakoram Anomaly.

scholarly journals Temporal Means and Variability of Arctic Sea Ice Melt and Freeze Season Climate Indicators Using a Satellite Climate Data Record

2018 ◽  
Vol 10 (9) ◽  
pp. 1328 ◽  
Author(s):  
Ge Peng ◽  
Michael Steele ◽  
Angela Bliss ◽  
Walter Meier ◽  
Suzanne Dickinson
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Climate Data ◽  
Ice Melt ◽  
Climate Indicators ◽  
Arctic Sea ◽  
Data Record ◽  
Climate Data Record ◽  
Snow And Ice Melt ◽  
Snow And Ice

Information on the timing of Arctic snow and ice melt onset, sea ice opening, retreat, advance, and closing, can be beneficial to a variety of stakeholders. Sea ice modelers can use information on the evolution of the ice cover through the rest of the summer to improve their seasonal sea ice forecasts. The length of the open water season (as derived from retreat/advance dates) is important for human activities and for wildlife. Long-term averages and variability of these dates as climate indicators are beneficial to business strategic planning and climate monitoring. In this study, basic characteristics of temporal means and variability of Arctic sea ice climate indicators derived from a satellite-based climate data record from March 1979 to February 2017 melt and freeze seasons are described. Our results show that, over the Arctic region, anomalies of snow and ice melt onset, ice opening and retreat dates are getting earlier in the year at a rate of more than 5 days per decade, while that of ice advance and closing dates are getting later at a rate of more than 5 days per decade. These significant trends resulted in significant upward trends for anomalies of inner and outer ice-free periods at a rate of nearly 12 days per decade. Small but significant downward trends of seasonal ice loss and gain period anomalies were also observed at a rate of −1.48 and −0.53 days per decade, respectively. Our analyses also demonstrated that the means of these indicators and their trends are sensitive to valid data masks and regional averaging methods.

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