scholarly journals Modeling Hydrological Response to Climate Change in a Data-Scarce Glacierized High Mountain Astore Basin Using a Fully Distributed TOPKAPI Model

Climate ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 127
Author(s):  
Atif ◽  
Iqbal ◽  
Su
Keyword(s):  
Air Temperature ◽  
Water Scarcity ◽  
Surface Runoff ◽  
Water Policy ◽  
Monsoon Season ◽  
Global Scale ◽  
Indus Basin ◽  
High Mountain ◽  
Kinematic Approximation ◽  
Storage Structures

Water scarcity is influencing environmental and socio-economic development on a global scale. Pakistan is ranked third among the countries facing water scarcity. This situation is currently generating intra-provincial water disputes and could lead to transboundary water conflicts. This study assessed the future water resources of Astore basin under representative concentration pathways (RCP) 4.5 and 8.5 scenarios using fully distributed TOPographic Kinematic APproximation and Integration (TOPKAPI) model. TOPKAPI model was calibrated and validated over five years from 1999–2003 with a Nash coefficient ranging from 0.93–0.97. Towards the end of the 21st century, the air temperature of Astore will increase by 3°C and 9.6 °C under the RCP4.5 and 8.5 scenarios, respectively. The rise in air temperature can decrease the snow cover with Mann Kendall trend of –0.12%/yr and –0.39%/yr (p ≥ 0.05) while annual discharge projected to be increased 11% (p ≤ 0.05) and 37% (p ≥ 0.05) under RCP4.5 and RCP8.5, respectively. Moreover, the Astore basin showed a different pattern of seasonal shifts, as surface runoff in summer monsoon season declined further due to a reduction in precipitation. In the spring season, the earlier onset of snow and glacier melting increased the runoff due to high temperature, regardless of the decreasing trend of precipitation. This increased surface runoff from snow/glacier melt of Upper Indus Basin (UIB) can potentially be utilized to develop water policy and planning new water harvesting and storage structures, to reduce the risk of flooding.

Water Governance and Management in Indus Basin - Challenges & Threats

2020 ◽  
Vol 38 (3) ◽  
Author(s):  
Marium Sara Minhas Bandeali
Keyword(s):  
Water Management ◽  
Civil Society ◽  
Water Resources ◽  
Water Policy ◽  
Water Governance ◽  
Sustainable Use ◽  
Water Security ◽  
Sampling Technique ◽  
The State ◽  
Indus Basin

Water governance and management are important challenges for the River Indus Basin in Pakistan. Water governance refers to social, political and economic factors that influence water management. The water scarcity and water security are a major concern for the state to control its water resources. The study aims to give Sindh water policy by exploring the challenges to Indus Basin in managing water resources and to identify opportunities Indus Basin can look to improve water management. Interviews were conducted from water experts and analysts having 5 years’ experience or more in the water sector of Pakistan through a semi-structured self-developed questionnaire using purposive sampling technique and transcripts were analyzed using thematic content analysis. The findings show that increasing population, climatic change and rising demand of water are major challenges Indus is facing and Indus with time is getting water-scarce therefore need strong institutions, civil society and legislatures to ensure equitable distribution of water and maintain the ecosystem. The study emphasizes that water governance and management are necessary for sustainable use of water. Pakistan, the water stress country needs to address ‘governance’ at a wider scale to solve problems in the Indus Basin for the livelihood of people. The research will benefit the state, water experts, institutions as well as civil society to promote efficient use of water in Indus Basin.

scholarly journals 8-Day and Daily Maximum and Minimum Air Temperature Estimation via Machine Learning Method on a Climate Zone to Global Scale

2021 ◽  
Vol 13 (12) ◽  
pp. 2355
Author(s):  
Linglin Zeng ◽  
Yuchao Hu ◽  
Rui Wang ◽  
Xiang Zhang ◽  
Guozhang Peng ◽  
...  
Keyword(s):  
Spatial Scale ◽  
Air Temperature ◽  
Spatial Scales ◽  
Model Performance ◽  
Global Scale ◽  
Scale Model ◽  
Validation Dataset ◽  
Daily Maximum ◽  
Climate Zone ◽  
Temporal And Spatial

Air temperature (Ta) is a required input in a wide range of applications, e.g., agriculture. Land Surface Temperature (LST) products from Moderate Resolution Imaging Spectroradiometer (MODIS) are widely used to estimate Ta. Previous studies of these products in Ta estimation, however, were generally applied in small areas and with a small number of meteorological stations. This study designed both temporal and spatial experiments to estimate 8-day and daily maximum and minimum Ta (Tmax and Tmin) on three spatial scales: climate zone, continental and global scales from 2009 to 2018, using the Random Forest (RF) method based on MODIS LST products and other auxiliary data. Factors contributing to the relation between LST and Ta were determined based on physical models and equations. Temporal and spatial experiments were defined by the rules of dividing the training and validation datasets for the RF method, in which the stations selected in the training dataset were all included or not in the validation dataset. The RF model was first trained and validated on each spatial scale, respectively. On a global scale, model accuracy with a determination coefficient (R2) > 0.96 and root mean square error (RMSE) < 1.96 °C and R2 > 0.95 and RMSE < 2.55 °C was achieved for 8-day and daily Ta estimations, respectively, in both temporal and spatial experiments. Then the model was trained and cross-validated on each spatial scale. The results showed that the data size and station distribution of the study area were the main factors influencing the model performance at different spatial scales. Finally, the spatial patterns of the model performance and variable importance were analyzed. Both daytime and nighttime LST had a significant contribution in the 8-day Tmax estimation on all the three spatial scales; while their contribution in daily Tmax estimation varied over different continents or climate zones. This study was expected to improve our understanding of Ta estimation in terms of accuracy variations and influencing variables on different spatial and temporal scales. The future work mainly includes identifying underlying mechanisms of estimation errors and the uncertainty sources of Ta estimation from a local to a global scale.

ON THE THERMAL REGIME OF THE SURFACE AIR LAYER IN THE DEBED RIVER BASIN (ARMENIA)

2021 ◽  
Vol 1 (1) ◽  
pp. 31-44
Author(s):  
MARGARYAN V.G. ◽  
Keyword(s):  
River Basin ◽  
Air Temperature ◽  
Thermal Regime ◽  
Time Course ◽  
Temporal Distribution ◽  
Thermal Conditions ◽  
High Mountain ◽  
Air Temperatures ◽  
Using Data ◽  
Surface Air Layer

The features of the thermal regime of the surface air layer in the Debed river basin are considered. A statistical analysis of the average annual and average seasonal values of air temperature from 1964 to 2018 was carried out, two periods were identified, their time course was shown. The analysis was carried out using data from six meteorological stations representing the lowland, mountain and high-mountain climatic zones of the Debed river basin. A correlation was obtained between the absolute altitude and the monthly average values of air temperature for January and July, which can be used to assess the thermal conditions of unexplored or poorly studied territories and for cartography. The time course of average values of air temperatures for the seasonal period has been studied. Analysis of trend lines of temporal changes in air temperatures shows that in all situations on the territory of the basin as a whole, there is a tendency of temperature growth. Moreover, with a range of interannual fluctuations, a break in the course of temperatures in the early to mid 1990 is clearly visible, after which their significant increase began. It turned out that a significant increase in seasonal temperatures is observed especially over the period 1993-2018, which means that the annual warming after the mid 1990 occurred primarily due to summer and spring seasons. The regular dynamics indicates that in the studied area in terms of temperatures, a tendency of softening winters, a decrease in the water content of rivers, aridization of the climate. The results obtained can be used to assess the regularities of the spatial-temporal distribution of the temperature of the study area, to clarify the thermal balance, for the rational use of heat resources, as well as in the development of strategic programs for longterm analysis.

scholarly journals Evidence of elevation-dependent warming from the Chinese Tian Shan

2021 ◽  
Vol 15 (12) ◽  
pp. 5765-5783
Author(s):  
Lu Gao ◽  
Haijun Deng ◽  
Xiangyong Lei ◽  
Jianhui Wei ◽  
Yaning Chen ◽  
...  
Keyword(s):  
Air Temperature ◽  
Minimum Temperature ◽  
Swiss Alps ◽  
Maximum Temperature ◽  
Current Evidence ◽  
High Mountain ◽  
Regional Warming ◽  
Mean Temperature ◽  
Warming Rate ◽  
Tian Shan

Abstract. The phenomenon in which the warming rate of air temperature is amplified with elevation is termed elevation-dependent warming (EDW). It has been clarified that EDW can accelerate the retreat of glaciers and melting of snow, which can have significant impacts on the regional ecological environment. Owing to the lack of high-density ground observations in high mountains, there is widespread controversy regarding the existence of EDW. Current evidence is mainly derived from typical high-mountain regions such as the Swiss Alps, the Colorado Rocky Mountains, the tropical Andes and the Tibetan Plateau–Himalayas. Rare evidence in other mountain ranges has been reported, especially in arid regions. In this study, EDW features (regional warming amplification and altitude warming amplification) in the Chinese Tian Shan (CTM) were detected using a unique high-resolution (1 km, 6-hourly) air temperature dataset (CTMD) from 1979 to 2016. The results showed that there were significant EDW signals at different altitudes on different timescales. The CTM showed significant regional warming amplification in spring, especially in March, and the warming trends were greater than those of continental China with respect to three temperatures (minimum temperature, mean temperature and maximum temperature). The significance values of EDW above different altitude thresholds are distinct for three temperatures in 12 months. The warming rate of the minimum temperature in winter showed a significant elevation dependence (p<0.01), especially above 3000 m. The greatest altitudinal gradient in the warming rate of the maximum temperature was found above 4000 m in April. For the mean temperature, the warming rates in June and August showed prominent altitude warming amplification but with different significance above 4500 m. Within the CTM, the Tolm Mountains, the eastern part of the Borokoonu Mountains, the Bogda Mountains and the Balikun Mountains are representative regions that showed significant altitude warming amplification on different timescales. This new evidence could partly explain the accelerated melting of snow in the CTM, although the mechanisms remain to be explored.

scholarly journals Recent changes of relative humidity: regional connection with land and ocean processes

2017 ◽  
Author(s):  
Sergio M. Vicente-Serrano ◽  
Raquel Nieto ◽  
Luis Gimeno ◽  
Cesar Azorin-Molina ◽  
Anita Drumond ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Interannual Variability ◽  
Air Temperature ◽  
Spatial Scales ◽  
Global Scale ◽  
Sea Surface ◽  
Positive Trend ◽  
Source Regions ◽  
Strong Agreement

Abstract. We analyzed changes in surface relative humidity (RH) at the global scale from 1979 to 2014 using both observations and ERA-Interim dataset. We compared the variability and trends of RH with those of land evapotranspiration and ocean evaporation in moisture source areas across a range of selected regions worldwide. The sources of moisture for each particular region were identified by integrating different observational data and model outputs into a lagrangian approach. The aim was to account for the possible role of changes in air temperature over land, in comparison to sea surface temperature (SST), on RH variability. Results demonstrate a strong agreement between the interannual variability of RH and the interannual variability of precipitation and land evapotranspiration in regions with continentally-originated humidity. In contrast, albeit with the dominant positive trend of air temperature/SST ratio in the majority of the analyzed regions, the interannual variability of RH in the target regions did not show any significant correlation with this ratio over the source regions. Also, we did not find any significant association between the interannual variability of oceanic evaporation in the oceanic humidity source regions and RH in the target regions. Our findings stress the need for further investigation of the role of both dynamic and radiative factors in the evolution of RH over continental regions at different spatial scales.

scholarly journals Modelling supraglacial debris-cover evolution from the single glacier to the regional scale: an application to High Mountain Asia

2021 ◽  
Author(s):  
Loris Compagno ◽  
Matthias Huss ◽  
Evan Stewart Miles ◽  
Michael James McCarthy ◽  
Harry Zekollari ◽  
...  
Keyword(s):  
Mass Balance ◽  
Temporal Evolution ◽  
Regional Scale ◽  
Global Scale ◽  
High Mountain ◽  
Surface Mass ◽  
Future Evolution ◽  
Debris Cover ◽  
Scale Modelling ◽  
Spatio Temporal

Abstract. Currently, about 12–13 % of High Mountain Asia's glacier area is debris-covered, altering its surface mass balance. However, in regional-scale modelling approaches, debris-covered glaciers are typically treated as clean-ice glaciers, leading to a potential bias when modelling their future evolution. Here, we present a new approach for modelling debris area and thickness evolution, applicable from single glaciers to the global scale. We implement the module into the Global Glacier Evolution Model (GloGEMflow), a combined mass-balance ice-flow model. The module is initialized with both glacier-specific observations of the debris’ spatial distribution and estimates of debris thickness, accounts for the fact that debris can either enhance or reduce surface melt depending on thickness, and enables representing the spatio-temporal evolution of debris extent and thickness. We calibrate and evaluate the module on a select subset of glaciers, and apply the model using different climate scenarios to project the future evolution of all glaciers in High Mountain Asia until 2100. Compared to 2020, total glacier volume is expected to decrease by between 35 ± 15 % and 80 ±11 %, which is in line with projections in the literature. Depending on the scenario, the mean debris-cover fraction is expected to increase, while mean debris thickness is modelled to show only minor changes, albeit large local thickening is expected. To isolate the influence of explicitly accounting for supraglacial debris-cover, we re-compute glacier evolution without the debris-cover module. We show that glacier geometry, area, volume and flow velocity evolve differently, especially at the level of individual glaciers. This highlights the importance of accounting for debris-cover and its spatio-temporal evolution when projecting future glacier changes.

scholarly journals Evaluation of Infiltration Rainwater Drainage (IRD) System with Fully 3-D Numerical Simulation Approach

2021 ◽  
Vol 11 (19) ◽  
pp. 9144
Author(s):  
Jungkyu Ahn ◽  
Seongil Yeom ◽  
Sungwon Park ◽  
Thi Hoang Thao Nguyen
Keyword(s):  
Water Scarcity ◽  
Surface Runoff ◽  
Urban Areas ◽  
Model Simulation ◽  
Three Dimensional ◽  
Lag Time ◽  
Prototype Model ◽  
Scaled Model ◽  
Runoff Decrease ◽  
Peak Runoff

Water scarcity can mean scarcity in availability due to physical shortage, or scarcity in access due to the failure of institutions to ensure a continuously regular supply or due to a lack of adequate infrastructure. Water scarcity will be exacerbated as rapidly growing urban areas place heavy pressure on water resources. To solve these problems, various solutions have been applied, but a fundamental solution has not been applied. Recently, a researched and developed infiltration rainwater drainage (IRD) system is being applied with consideration of its applicability. In this study, features of surface runoff and infiltration according to various flow patterns were analyzed using a three-dimensional CFD (Computational Fluid Dynamics) model for calculating water flow in the IRD system. To estimate the optimal setup, a permeability test and scaled model simulation were performed. The runoff characteristics of the IRD system with respect to rainfall intensity and duration were analyzed with dimensionless variables. With the prototype model, the drainage characteristics of the IRD system were analyzed over time using the hydrological curves. From the simulated results, it was found that the IRD system analyzed in this study was appropriate in the field by comparative analysis with the existing system based on peak runoff, internal storage, and lag time. Therefore, by applying the IRD system in the future, it is expected that the IRD has benefits, such as delayed lag time, surface runoff decrease, and an attenuation of the peak runoff.

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