Evaluation of CMIP5 models and ensemble climate projections using a Bayesian approach: a case study of the Upper Indus Basin, Pakistan

2021 ◽  
Author(s):  
Firdos Khan ◽  
Jürgen Pilz ◽  
Shaukat Ali
Keyword(s):  
Bayesian Approach ◽  
Indus Basin ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Upper Indus Basin

scholarly journals Impacts of Climate Change on the Water Availability, Seasonality and Extremes in the Upper Indus Basin (UIB)

2020 ◽  
Vol 12 (4) ◽  
pp. 1283 ◽  
Author(s):  
Asim Khan ◽  
Manfred Koch ◽  
Adnan Tahir
Keyword(s):  
General Circulation ◽  
Extreme Values ◽  
Regional Climate ◽  
Total Duration ◽  
Future Climate ◽  
Indus Basin ◽  
Mean Annual Precipitation ◽  
Climate Projections ◽  
Climatic Data ◽  
Upper Indus Basin

Projecting future hydrology for the mountainous, highly glaciated upper Indus basin (UIB) is a challenging task because of uncertainties in future climate projections and issues with the coverage and quality of available reference climatic data and hydrological modelling approaches. This study attempts to address these issues by utilizing the semi-distributed hydrological model “Soil and water assessment tool” (SWAT) with new climate datasets and better spatial and altitudinal representation as well as a wider range of future climate forcing models (general circulation model/regional climate model combinations (GCMs_RCMs) from the “Coordinated Regional Climate Downscaling Experiment-South Asia (CORDEX-SA) project to assess different aspects of future hydrology (mean flows, extremes and seasonal changes). Contour maps for the mean annual flow and actual evapotranspiration as a function of the downscaled projected mean annual precipitation and temperatures are produced and can serve as a “hands-on” forecast tool of future hydrology. The overall results of these future SWAT hydrological projections indicate similar trends of changes in magnitudes, seasonal patterns and extremes of the UIB—stream flows for almost all climate scenarios/models/periods—combinations analyzed. In particular, all but one GCM_RCM model—the one predicting a very high future temperature rise—indicated mean annual flow increases throughout the 21st century, wherefore, interestingly, these are stronger for the middle years (2041–2070) than at its end (2071–2100). The seasonal shifts as well as the extremes follow also similar trends for all climate scenario/model/period combinations, e.g., an earlier future arrival (in May–June instead of July–August) of high flows and increased spring and winter flows, with upper flow extremes (peaks) projected to drastically increase by 50 to >100%, and with significantly decreased annual recurrence intervals, i.e., a tremendously increased future flood hazard for the UIB. The future low flows projections also show more extreme values, with lower-than-nowadays-experienced minimal flows occurring more frequently and with much longer annual total duration.

scholarly journals Migration as an Adaptation Strategy and its Gendered Implications: A Case Study From the Upper Indus Basin

2014 ◽  
Vol 34 (3) ◽  
pp. 255-265 ◽  
Author(s):  
Giovanna Gioli ◽  
Talimand Khan ◽  
Suman Bisht ◽  
Jürgen Scheffran
Keyword(s):  
Adaptation Strategy ◽  
Indus Basin ◽  
Upper Indus Basin

scholarly journals Hydrological Modeling of the Upper Indus Basin: A Case Study from a High-Altitude Glacierized Catchment Hunza

Water ◽  
2017 ◽  
Vol 9 (1) ◽  
pp. 17 ◽  
Author(s):  
Khan Garee ◽  
Xi Chen ◽  
Anming Bao ◽  
Yu Wang ◽  
Fanhao Meng
Keyword(s):  
High Altitude ◽  
Hydrological Modeling ◽  
Indus Basin ◽  
Upper Indus Basin

scholarly journals Future Hydrological Regimes in the Upper Indus Basin: A Case Study from a High-Altitude Glacierized Catchment

2015 ◽  
Vol 16 (1) ◽  
pp. 306-326 ◽  
Author(s):  
Andrea Soncini ◽  
Daniele Bocchiola ◽  
Gabriele Confortola ◽  
Alberto Bianchi ◽  
Renzo Rosso ◽  
...  
Keyword(s):  
High Altitude ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Ice Cover ◽  
Global Climate Models ◽  
Indus Basin ◽  
Rapid Decline ◽  
Climate Projections ◽  
Upper Indus Basin

Abstract The mountain regions of the Hindu Kush, Karakoram, and Himalayas (HKH) are considered Earth’s “third pole,” and water from there plays an essential role for downstream populations. The dynamics of glaciers in Karakoram are complex, and in recent decades the area has experienced unchanged ice cover, despite rapid decline elsewhere in the world (the Karakoram anomaly). Assessment of future water resources and hydrological variability under climate change in this area is greatly needed, but the hydrology of these high-altitude catchments is still poorly studied and little understood. This study focuses on a particular watershed, the Shigar River with the control section at Shigar (about 7000 km2), nested within the upper Indus basin and fed by seasonal melt from two major glaciers (Baltoro and Biafo). Hydrological, meteorological, and glaciological data gathered during 3 years of field campaigns (2011–13) are used to set up a hydrological model, providing a depiction of instream flows, snowmelt, and ice cover thickness. The model is used to assess changes of the hydrological cycle until 2100, via climate projections provided by three state-of-the-art global climate models used in the recent IPCC Fifth Assessment Report under the representative concentration pathway (RCP) emission scenarios RCP2.6, RCP4.5, and RCP8.5. Under all RCPs, future flows are predicted to increase until midcentury and then to decrease, but remaining mostly higher than control run values. Snowmelt is projected to occur earlier, while the ice melt component is expected to increase, with ice thinning considerably and even disappearing below 4000 m MSL until 2100.

A Hydrological Perspective on Interpretation of Available Climate Projections for the Upper Indus Basin

2019 ◽  
pp. 159-179 ◽  
Author(s):  
Nathan Forsythe ◽  
David R. Archer ◽  
David Pritchard ◽  
Hayley Fowler
Keyword(s):  
Indus Basin ◽  
Climate Projections ◽  
Upper Indus Basin

scholarly journals Selecting and Downscaling a Set of Climate Models for Projecting Climatic Change for Impact Assessment in the Upper Indus Basin (UIB)

2018 ◽  
Author(s):  
Asim Jahangir Khan ◽  
Manfred Koch
Keyword(s):  
Climate Models ◽  
Climate Change Impacts ◽  
Indus Basin ◽  
Climate Projections ◽  
Upper Indus Basin ◽  
Mountainous Regions ◽  
Precipitation Decrease ◽  
Late 21St Century ◽  
Weighted Score ◽  
Precipitation Changes

This study focusses on identifying a set of representative future climate projections for the Upper Indus Basin (UIB). Although a large number of GCM’s predictor sets are nowadays available in the CMIP5 archive, the issue of their reliability for specific regions must still be confronted. This situation makes it imperative to sort out the most appropriate, single or small-ensemble set of GCMs for the assessment of climate change impacts in a region. Here a set of different approaches is adopted and applied for a step-wise shortlist and selection of appropriate climate models for the UIB under two RCPs: RCP 4.5 and RCP 8.5, based on, a) range of projected mean changes, b) range of projected extreme changes, and c) skill in reproducing the past climate. Furthermore, because of higher uncertainties in climate projection for high mountainous regions like the UIB, a wider range of future GCM climate projections is considered by using all possible future extreme scenarios (wet-warm, wet-cold, dry-warm, dry-cold). Based on this two-fold procedure, a limited number of climate models is pre-selected, out of which the final selection is done by assigning ranks to the weighted score for each of the mentioned selection criteria. The dynamically downscaled climate projections from the Coordinated Regional Downscaling Experiment (CORDEX) available for the top-ranked GCMs are further statistically downscaled (bias-corrected) over the UIB. The downscaled projections up to year 2100 indicate temperature increases ranging between 2.3 °C and 9.0 °C and precipitation changes that range, from a slight annual increase of 2.2% under the drier scenarios,  to as high as 15.9% for the wet scenarios.  Moreover, for all scenarios, the future precipitation will be more extreme, as the probability of wet days will decrease, while, at the same time, the precipitation intensities will increase. The spatial distribution of the downscaled predictors across the UIB also shows similar patterns for all scenarios, with a distinct precipitation decrease over the south-eastern parts of the basin, but an increase in the northeastern parts. These two features are particularly intense for the “Dry-Warm” and the “Median” scenarios over the late 21st century.

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