Impacts of climate and land use change on groundwater recharge under shared socioeconomic pathways: A case of Siem Reap, Cambodia.

The rapid pace of urbanization blended with climate change has significantly altered surface and groundwater flows. In the context of tourism-driven economic potential areas, these drivers have greater effects, including threatening groundwater availability. This study assessed the combined impacts of climate and land use changes on the groundwater recharge (GWR) in Siem Reap, Cambodia utilizing Phase Six of the Coupled Model Intercomparison Project (CMIP6) global climate models (GCMs), DynaCLUE land-use model, and Soil Water Assessment Tool (SWAT). Three climate models CanESM5, EC_Earth3, and MIROC6, out of seven, best captured the observed data after performance evaluation through the entropy method, were bias-corrected linearly for two shared socioeconomic pathways (SSPs) - SSP2-4.5 and SSP5-8.5. The results indicate a general increase in precipitation under both SSPs, while the average annual maximum temperature is likely to increase by 0.024 °C/year and 0.049 °C/year under SSP2-4.5 and SSP5-8.5, respectively. A similar trend but relatively higher increase is expected for the minimum temperature. Furthermore, the historical land use change showed the expansion of urban settlement by 373% between 2004 and 2019 at the expense of forest and shrubland. Future land use projections from the DynaCLUE model show that the urban settlements in the study area are likely to expand, from their 2019 condition, by 55% in 2030, 209% in 2060, and 369% in 2090 under SSP2 and at double of these rates under SSP5 scenario. The GWR is expected to rise by 39-53% during the wet season and decrease by 13-29% during the dry season under both scenarios. Meanwhile, under constant land use, the GWR is likely to increase more compared to other scenarios, highlighting the importance of land use planning to policymakers and planners. Additionally, the study shall also be important to practitioners and researchers in understanding, planning, and evaluating the performance of multiple climate models in groundwater assessment.

Assessing the future climate change, land use change, and abstraction impacts on groundwater resources in the Tak Special Economic Zone, Thailand.

Groundwater is an important source of water supply in the Tak Special Economic Zone of Thailand. However, groundwater is under stress from climate change, land use change, and an increase in abstraction, affecting the groundwater level and its sustainability. Therefore, this study analyses the impact of these combined stresses on groundwater resources in the near, mid, and far future. Three Global Climate Models are used to project the future climate under SSP2-4.5 and SSP5-8.5 scenarios. According to the results, both maximum and minimum temperatures are likely to show similar increasing trends for both scenarios, with a rise of approximately 1 (1.5), 2 (3), and 3 (5) °C expected for SSP2-4.5 (SSP5-8.5) in each consecutive period. Annual rainfall is expected to continually increase in the future, with around 1500-1600 mm in rainfall (11ꟷ5.43% higher). Land use change is predicted for two scenarios: business as usual (BU) and rapid urbanisation (RU). The forest area is expected to increase to 30% (35%) coverage in 2090 for BU (RU) while agriculture is likely to reduce to 60% (50%) with the urban area increasing to 2.4% (7%). Water demand is predicted to increase in all future scenarios. The SWAT model is used to project recharge, which is likely to increase by 10-20% over time. The highest increase is predicted in the far future under SSP2 and RU scenarios. MODFLOW was used to project future groundwater resources, but due to the lack of consistent data, the time scale is reduced to yearly simulation. The results reveal that the groundwater level is expected to increase in the central part (urban area) of the study area and decrease along the boundary (agricultural area) of the aquifer. This research can aid policymakers and decision-makers in understanding the impact of multiple stressors and formulating adaptation strategies to manage groundwater resources in special economic zones.

Evaluating aquifer stress and resilience with GRACE information at different spatial scales in Cambodia.

Groundwater exploitation for different sectors in Cambodia is expanding. Groundwater levels have already begun to decline in some parts of the country. Monitoring and assessing groundwater storage (GWS) change, aquifer stress and aquifer resilience will support the proper planning and management of the country's groundwater resources; however, information regarding groundwater in Cambodia is currently scarce. Thus, GWS change in Cambodia over the 15 years from April 2002 to March 2017 was assessed using remote-sensing-based Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) datasets, with a comprehensive validation of the GRACE-derived groundwater storage anomaly (GWSA) with respect to in-situ field-based observations. The current study also investigated the impact of surface water storage (SWS) change in Tonle Sap Lake, South-East Asia's largest freshwater lake, on deriving the GWS change in Cambodia. The groundwater aquifer stresses (GAS), and aquifer resilience (AR) were also evaluated. The validation results were promising, with the correlation coefficient between satellite-based estimations and ground-based measurements ranging from 0.82 to 0.88 over four subbasins. The overall decreasing rate of GWS was found to be -0.63 mm/month, with two basins having the highest declining rate of more than 1.4 mm/month. Meanwhile, the aquifer experiencing stress during the dry season had a very low ability to quickly recover from these stresses. These findings emphasise that appropriate management is urgently needed to ensure the sustainability of the groundwater resource system in this country. Supplementary Information: The online version contains supplementary material available at 10.1007/s10040-022-02570-w.

L'exploitation des eaux souterraines s'étend au Cambodge dans différents secteurs. Les niveaux piézométriques ont déjà commencé à baisser sur quelques secteurs du pays. Surveiller et évaluer les changements de stock d'eau souterraine (GWS), la pression sur les aquifères et leur résilience supportera une planification et gestion correctes des ressources en eau dans le pays; toutefois, les informations en relation avec les eaux souterraines sont peu nombreuses aujourd'hui au Cambodge. Ainsi, les changements de GWS au Cambodge sur les 15 dernières années, d'avril 2002 à mars 2017 ont été évalués à l'aide des méthodes de télédétection basées sur le Gravity Recovery and Climate Experiment (GRACE) et les jeux de données du Global Land Data Assimilation System (GLDAS) avec une validation complète des anomalies de stockage d'eau souterraine (GWSA) de GRACE par l'utilisation d'observations de terrain. L'étude a également permis d'étudier l'impact des changements de stocks d'eau de surface (SWS) dans le lac Tonle Sap, le plus grand lac d'eau douce du sud-est asiatique, par dérivation des changements de GWS au Cambodge. Les pressions sur les eaux souterraines (GAS) et la résilience des aquifère (AR) ont également été évaluées. La validation des résultats est prometteuse, avec un coefficient de corrélation entre les estimations basées sur les données satellitaires et les mesures de terrain allant de 0.82 à 0.88 sur quatre sous-bassins. Un taux de baisse globale du GWS de ­0.63 mm/mois a été estimé, avec deux sous-bassins ayant des baisses plus fortes de plus de 1.4 mm/mois. Sur la même période, les aquifère qui subissent un stress durant les basses eaux montrent une faible capacité à récupérer de ce stress. Ces résultats montrent qu'une gestion adéquate est urgemment nécessaire pour assurer la durabilité de la ressource en eau souterraine dans ce pays.

La explotación de las aguas subterráneas para diferentes sectores en Camboya está en expansión. Los niveles de las aguas subterráneas ya han empezado a descender en algunas partes del país. El seguimiento y la evaluación de los cambios en el almacenamiento de las aguas subterráneas (GWS), el estrés del acuífero y la resiliencia del acuífero apoyarán la planificación y la gestión adecuadas de los recursos de aguas subterráneas del país; sin embargo, la información relativa a las aguas subterráneas en Camboya es actualmente escasa. Por lo tanto, se evaluó el cambio de GWS en Camboya durante los últimos 15 años, desde abril de 2002 hasta marzo de 2017, utilizando conjuntos de datos del Gravity Recovery and Climate Experiment (GRACE) y del Global Land Data Assimilation System (GLDAS) basados en la teledetección, con una validación exhaustiva de la anomalía de almacenamiento de aguas subterráneas (GWSA) derivada de GRACE con respecto a las observaciones in situ sobre el terreno. El presente estudio también investigó el impacto del cambio en el almacenamiento de agua superficial (SWS) en el lago Tonle Sap, el mayor lago de agua dulce del sudeste asiático, en la derivación del cambio del GWS en Camboya. También se evaluaron las tensiones de los acuíferos subterráneos (GAS) y la resistencia de los acuíferos (AR). Los resultados de la validación fueron promisorios, ya que el coeficiente de correlación entre las estimaciones basadas en satélites y las mediciones terrestres osciló entre 0.82 y 0.88 en cuatro subcuencas. La tasa global de disminución del GWS fue de ­0.63 mm/mes, con dos cuencas con la tasa de disminución más alta, de más de 1.4 mm/mes. Mientras tanto, el acuífero que experimentaba estrés durante la estación seca tenía una capacidad muy baja para recuperarse rápidamente de estas tensiones. Estos resultados ponen de relieve que se necesita urgentemente una gestión adecuada para garantizar la sostenibilidad del sistema de recursos hídricos subterráneos en este país.

A exploração de águas subterrâneas para diferentes setores no Camboja está se expandindo. Os níveis das águas subterrâneas já começaram a diminuir em algumas partes do país. O monitoramento e avaliação das mudanças no armazenamento de águas subterrâneas (AASub), estresse e resiliência do aquífero apoiarão o planejamento e a gestão adequados dos recursos hídricos subterrâneos do país; no entanto, as informações sobre as águas subterrâneas no Camboja são atualmente escassas. Assim, a mudança de AASub no Camboja nos últimos 15 anos, de abril de 2002 a março de 2017, foi avaliada usando conjuntos de dados Gravity Recovery and Climate Experiment (GRACE) e Global Land Data Assimilation System (GLDAS) baseados em sensoriamento remoto, com uma validação abrangente da anomalia de armazenamento de água subterrânea derivada do GRACE (AAASub) em relação a observações baseadas em campo. O estudo atual também investigou o impacto da mudança de armazenamento de água de superfície (AASup) no Lago Tonle Sap, o maior lago de água doce do Sudeste Asiático, na derivação da mudança de AASub no Camboja. Os estresses das águas subterrâneas no aquífero (SASub) e a resiliência do aquífero (RA) também foram avaliados. Os resultados da validação foram promissores, com o coeficiente de correlação entre as estimativas baseadas em satélite e as medições terrestres variando de 0.82 a 0.88 em quatro sub-bacias. A taxa global decrescente de AAS foi de ­0.63 mm/mês, com duas bacias tendo a maior taxa de declínio de mais de 1.4 mm/mês. Enquanto isso, o aquífero submetido a estresse durante a estação seca teve uma capacidade muito baixa de se recuperar rapidamente desses estresses. Esses achados enfatizam que uma gestão adequada é urgentemente necessária para garantir a sustentabilidade do sistema de recursos hídricos subterrâneos neste país.

Reconstructing NDVI and land surface temperature for cloud cover pixels of Landsat-8 images for assessing vegetation health index in the Northeast region of Thailand.

Critical applications of satellite data products include monitoring vegetation dynamics and assessing vegetation health conditions. Some indicators like normalized difference vegetation index (NDVI) and land surface temperature (LST) are used to assess the status of vegetation growth and health. But one of the major problems with passive remote sensing satellite data products is cloud and shadow cover that leads to data gaps in the images. The present study proposes temporal aggregation of images over a short time span and developing short span harmonic analysis of time series (SS-HANTS) and pixel-wise multiple linear regression (PMLR) algorithms for retrieving cloud contaminated NDVI and LST information from Landsat-8 (L8) data products, respectively. The developed algorithms were applied in the northeastern part of Thailand to recover the missing NDVI and LST values from time series L8 images acquired in 2018. The predicted NDVI and LST values at artificially clouded locations were compared with the corresponding clear pixel values. Additionally, the model predicted LST and NDVI values were also compared with MODIS LST and NDVI datasets. The calculated root mean square (RMSE) values were ranging from 0.03 to 0.11 and 1.50 to 2.98 °C for NDVI and LST variables, respectively. The validation statistics show that these models can be satisfactorily applied to retrieve NDVI and LST values from cloud-contaminated pixels of L8 images. Furthermore, a vegetation health index (VHI) computed from cloud retrieved continuous NDVI and LST images at province level shows that most of the western provinces have healthy vegetation condition than other provinces in the northeast of Thailand.

Herpes zoster following vaccination with ChAdOx1 nCoV-19 Coronavirus vaccine (recombinant).

Ever since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, science has unraveled much knowledge on SARS-CoV-2 which has led to extraordinary and unprecedented progress in developing COVID-19 vaccines. Several adverse cutaneous reactions, ranging from more common local injection site reaction, neutrophilic and pustular drug reactions to flare-up of preexisting dermatoses, have been reported with currently available vaccines. We report a case series of 7 patients who developed herpes zoster (HZ) following the first dose of ChAdOx1 nCoV-19 coronavirus vaccine (recombinant). HZ following vaccination is a rare entity. The occurrence of HZ in the patients presented in this series within the time window 1-21 days after vaccination defined for increased risk and postulated dysregulation of T-cell-mediated immunity, suggests that the ChAdOx1 nCoV-19 coronavirus vaccine (recombinant) could probably be a trigger for reactivation of varicella zoster virus to cause HZ in them.

Multiple drivers of hydrological alteration in the transboundary Srepok River Basin of the Lower Mekong Region.

Human-induced changes in land and water resources adversely affect global hydrological regimes. Hydrological alteration of the natural flow regime is considered to have a significant damaging and widespread impact on river ecosystems and livelihoods. Therefore, understanding the hydrological alteration of rivers and the potential driving factors affecting such alterations are crucial to effective water resources management. This study analyses the impact of changes in land use, climate, and hydropower development on the hydrological regime of the Srepok River Basin in the Lower Mekong Region. The Lower Mekong Basin (LMB) in Southeast Asia is known for its agriculture, forests, fisheries, wildlife, and diverse natural ecosystems. Historical land use and climate change are quantified (utilising European Space Agency land cover and observed meteorological data) and correlated with the hydrological indicators using the Indicators of Hydrologic Alteration (IHA) software. Moreover, pre and post impacts on the hydrological regime by hydropower development are quantified using the Range of Variability Approach (RAV) in IHA software. The results reveal that land use, rainfall, and temperature affect different aspects of the hydrological regime, with corroborating evidence to support variation among the most correlated IHA and environmental flow component (EFC) parameters with the three drivers. The highest and lowest correlations among the IHA and EFC parameters under each driver are against land use (0.85, -0.83), rainfall (0.78, -0.54), and minimum and max temperatures (0.42, -0.47). Among the parameters, the fall rate has the most significant effect on hydrological alteration of all drivers. Hydropower development in the basin mostly affects the fall rate and reversal. Identifying the connection between these multiple drivers and hydrological alteration could help decision-makers to design more efficient and sustainable water management policies.

Rationale, study design and methodology of the LANDMARC trial: a 3-year, pan-India, prospective, longitudinal study to assess management and real-world outcomes of diabetes mellitus.

AIM: India contributes towards a large part of the worldwide epidemic of diabetes and its associated complications. However, there are limited longitudinal studies available in India to understand the occurrence of diabetes complications over time. This pan-India longitudinal study was initiated to assess the real-world outcomes of diabetes across the country. METHODS: The LANDMARC study is the first prospective, multicentre, longitudinal, observational study investigating a large cohort of people with type 2 diabetes mellitus across India over a period of 3 years. The primary objective of this ongoing study is to determine the proportion of people developing macrovascular diabetes complications over the duration of the study (36 months ± 45 days) distributed over seven visits; the secondary objective is to evaluate microvascular diabetes complications, glycaemic control and time-to-treatment adaptation or intensification. Overall, 6300 participants (aged 25-60 years) diagnosed with type 2 diabetes for at least 2 years will be included from 450 centres across India. Data will be recorded for baseline demographics, comorbidities, glycaemic measurements, use of anti-hyperglycaemic medications and any cardiovascular or other diabetes-related events occurring during the observational study period. CONCLUSIONS: The LANDMARC study is expected to reveal the trends in complications associated with diabetes, treatment strategies used by physicians, and correlation among treatment, control and complications of diabetes within the Indian context. The findings of this study will help to identify the disease burden, emergence of early-onset complications and dose titration patterns, and eventually develop person-centred care and facilitate public health agencies to invest appropriate resources in the management of diabetes. (Trial Registration No: CTRI/2017/05/008452).

Impacts of land-use changes on the groundwater recharge in the Ho Chi Minh city, Vietnam.

Ho Chi Minh City (HCMC), Vietnam has undergone tremendous transformation in land-use practices in the past few decades. The groundwater-related issues have also been a major concern in the fast-growing southern city of Vietnam. Quantitative prediction of the impact on groundwater recharge due to changes in the land-use pattern of a watershed is crucial in developing sound groundwater management schemes. This study aims to evaluate the impacts of change in land-use patterns on the quantity of groundwater recharge in HCMC. An empirical land-use projection model (Conversion of Land-use and its Effects, Dyna-CLUE) and a hydrological model (Soil and Water Assessment Tool, SWAT) was used for the study. Three future land-use scenarios of Low Urbanization Scenario (LU), Medium Urbanization Scenario (MU) and High Urbanization Scenario (HU) were developed in Dyna-CLUE focusing on the increase of built-up area to generate land-use maps of HCMC until the year 2100. The land-use maps for all three scenarios were then used in the calibrated hydrological model SWAT to get the future recharge in the near future (2016-2045), mid future (2046-2075) and far future (2076-2100). The recharge was observed to increase in the far future of LU by 10% while reduction of 30% and 52% in annual average recharge was observed in far future of MU and HU respectively. It was, thus, observed that change in built-up area has a significant effect on the groundwater recharge in HCMC.

Assessment of climate change impacts on water balance and hydrological extremes in Bang Pakong-Prachin Buri river basin, Thailand.

Among many factors the hydrology of a watershed is mainly influenced by climate and land use change. This study examined the impacts of climate change on water resources and extreme events in the Bang Pakong-Prachin Buri River Basin, Thailand using three different Regional Climate Models (RCMs) ACCESS1-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM, and MPI-ESM-LR-CSIRO-CCAM under RCP4.5 and RCP8.5 emission scenarios. Soil and Water Assessment Tool (SWAT) was used to simulate the future streamflow and Extreme Value Type I distribution (EVI) was used to analyze the extreme events under projected climate conditions. The result of this study showed an increase in maximum (1.9 °C/3.6 °C) and minimum (1.6 °C/3.3 °C) temperatures under RCP4.5/8.5 at the end of the 21st century. In addition, projected rainfall is expected to decrease up to 6.8% (8.5%) in 2050s and then increase slowly such that the decrement remains 4.2% (11.0%) under RCP4.5 (RCP8.5) at the end of the century. The rainfall pattern is projected to considerably fluctuate, in particular, a shift in long term average annual peak event from September to August is predicted in 2080s under emission scenario RCP4.5 (RCP8.5). On the other hand, the average annual discharge is expected to increase up to 13.5% (2020s) and 7.6% (2050s) under RCP4.5 and RCP8.5 respectively with decreasing trend in low flows and increasing trend in high flows. Further analysis on extreme events; strengthened the results from hydrological modeling with an increase in flow volume for the same return period under changed climate conditions. This raises water resources management issues in the Bang Pakong-Prachin Buri River Basin regarding the frequency of flood and drought events in the future calling for proper policy formulation and implementation.

Mapping groundwater resiliency under climate change scenarios: A case study of Kathmandu Valley, Nepal.

Groundwater resources of Kathmandu Valley in Nepal are under immense pressure from multiple stresses, including climate change. Due to over-extraction, groundwater resources are depleting, leading to social, environmental and economic problems. Climate change might add additional pressure by altering groundwater recharge rates and availability of groundwater. Mapping groundwater resilience to climate change can aid in understanding the dynamics of groundwater systems, facilitating the development of strategies for sustainable groundwater management. Therefore, this study aims to analyse the impact of climate change on groundwater resources and mapping the groundwater resiliency of Kathmandu Valley under different climate change scenarios. The future climate projected using the climate data of RCM's namely ACCESS-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM and MPI-ESM-LR-CSIRO-CCAM for three future periods: near future (2010-2039), mid future (2040-2069) and far future (2070-2099) under RCP 4.5 and RCP 8.5 scenarios were bias corrected and fed into the Soil and Water Assessment Tool (SWAT), a hydrological model, to estimate future groundwater recharge. The results showed a decrease in groundwater recharge in future ranging from 3.3 to 50.7 mm/yr under RCP 4.5 and 19-102.1 mm/yr under RCP 8.5 scenario. The GMS-MODFLOW model was employed to estimate the future groundwater level of Kathmandu Valley. The model revealed that the groundwater level is expected to decrease in future. Based on the results, a groundwater resiliency map of Kathmandu Valley was developed. The results suggest that groundwater in the northern and southern area of the valley are highly resilient to climate change compared to the central area. The results will be very useful in the formulation and implementation of adaptation strategies to offset the negative impacts of climate change on the groundwater resources of Kathmandu Valley.

Downscaling Global Gridded Crop Yield Data Products and Crop Water Productivity Mapping Using Remote Sensing Derived Variables in the South Asia.

Local scale crop yield and crop water productivity information is critical for informed decision making, crop yield forecasting and crop model calibration applications. In this study, we have attempted to downscale coarse resolution primary season rice yield datasets to a local scale of 500 m using a minimum-median downscaling approach. Sixteen mainland countries in south and southeast Asia region were considered as study region to downscale global rice yield datasets for 2000-2015. Four medium resolution remote sensing derived vegetation indices such as Normalised Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), and Gross Primary Product (GPP) were used to downscale coarse resolution global rice yield datasets. A kharif season district level rice yield data from International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), India was used as a reference dataset to evaluate the downscaled rice yields at the district scale. The proposed downscaling approach performance was satisfactory with a mean absolute error (MAE) range of 0.85-1.2 t/ha which lies in the error range of 10-15% with respect to actual range of reference rice yield datasets. Furthermore, crop water productivity maps at 500 m scale were also developed with the downscaled rice yield and Moderate Resolution Imaging Spectroradiometer (MODIS) Evapotranspiration (ET) data products. Statistical analysis shows that the rice yield and crop water productivity values across different climate zones were statistically significant. Tropical zone-based crop yield and crop water productivity values were showing higher variation when compared to other climate zones with a range of 1-10 t/ha and 1-12.5 kg/m3, respectively. Supplementary Information: The online version contains supplementary material available at 10.1007/s42106-022-00223-2.

Mapping the vulnerability of irrigation sand traps in a tropical volcanic basin, Indonesia.

Sand traps in irrigation networks are typically used in mitigating canal sedimentation. In irrigation networks located in basins of high sediment yield due to the presence of volcanoes, it is essential to assess the vulnerability of sand traps. Using sediment yield at irrigation scheme inlets, sand trap vulnerability can be evaluated. This study aims to understand the vulnerability of irrigation sand traps throughout the Progo-Opak-Serang (POS) Volcanic River Basin, Indonesia, via mapping the sediment yield distributions in the basin. We employed the Revised Universal Soil Loss Equation to estimate soil loss, where the results show that the average soil loss in the POS River Basin is 179.69 tons/ha/year that falls under the category of moderate erosion potential, while the average sediment yield for the whole basin is 51.04 tons/ha/year. Parts of the basin with high yields of more than 180 tons/ha/year were mostly found along the volcanic mountains such as Sindoro, Sumbing, Merapi, Merbabu, and Telomoyo, and the Menoreh Hills. The model demonstrated relatively high performance with R2, NSE, RMSE, and MAE of 0.89, 0.82, 0.14, and 0.11, respectively. Within the POS Basin, Badran, Kalibawang, and Blawong are the three most vulnerable irrigation sand traps, with sediment yield values of 252.83, 178.92, and 63.49 tons/ha/year, respectively; they are all located in sub-watershed outlets. The vulnerability assessment conducted in this study can be used for the decision support system to prioritize irrigation sand traps towards a more effective irrigation system development.

Climate and land-use change impacts on spatiotemporal variations in groundwater recharge: A case study of the Bangkok Area, Thailand.

Groundwater contributes to the socioeconomic development of the Thai capital Bangkok and its vicinity. However, groundwater resources are under immense pressure due to population growth, rapid urbanisation, overexploitation, and climate change. Therefore, evaluating the combined impact of climate change and land-use change on groundwater recharge can be useful for developing sound groundwater management systems. In this research, the future climate is projected using three Regional Climate Models (RCMs), namely ACCESS-CSIRO-CCAM, CNRM-CM5-CSIRO-CCAM, and MPI-ESM-LR-CSIRO-CCAM for three future periods: near future (2010-2039), mid future (2040-2069), and far future (2070-2099) under two Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5 as suggested in the IPCC's Fifth Assessment Report. All RCMs project the temperature to rise incessantly, although future precipitation is predicted to fluctuate (increase and decrease) among the various RCMs and RCP scenarios. A Dyna-CLUE model is employed to analyse the future land-use change scenarios (low, medium, and high urbanisation), with the aim of expanding the built-up area and creating land-use maps covering the period to 2099. A hydrological model, WetSpass, is used to estimate groundwater recharge under future climate and land-use change. The findings reveal that groundwater recharge is expected to decrease in high and medium urbanisation areas, ranging from 5.84 to 20.91 mm/yr for the RCP 4.5 scenario and 4.07 to 18.72 mm/yr for RCP 8.5. In contrast, for the low urbanisation scenario, the model projects an increase in groundwater recharge ranging from 7.9 to 16.66 mm/yr for the RCP 4.5 scenario and 5.54 to 20.04 mm/yr for RCP 8.5.

Evaluation of the CORDEX regional climate models (RCMs) for simulating climate extremes in the Asian cities.

This study evaluates the ability of 21 Regional Climate Models (RCMs) from the Coordinated Regional Climate Downscaling Experiment (CORDEX) in simulating climate extremes in the fast growing Asian cities which are highly vulnerable to climate change. The three Asian cities have two different climate characteristics, namely Bangkok and its vicinity and Ho Chi Minh City in tropical climate region and Kathmandu in sub-tropical and temperate climate region. The RCMs were evaluated to simulate the six climate indices; Consecutive Dry Days (CDD), Simple Daily Intensity Index (SDII), Number of extremely heavy precipitation days (R50mm), Maximum 1-day precipitation amount (RX1day), Mean of daily maximum temperature (TX mean) and Mean of daily minimum temperature (TN mean). The performance indicators used were correlation coefficient, normalized root mean square deviation, absolute normalized root mean square deviation and average absolute relative deviation. The Entropy method was endorsed to acquire weights of these four indicators and weightage average techniques were used for ranking of 21 RCMs. The result demonstrated that the best model for one climate index is not the same best model for other climate indices. The 3 RCMs; WAS44_SMHI_RCA4_IPSL_CM5A_MR, WAS44_SMHI_RCA4_MIROC5, and WAS44_IITM_REGCM4-4_CSIRO_MK3-6-0 are the best performing RCMs for simulating future climate extremes in Bangkok and its vicinity, Ho Chi Minh city and Kathmandu valley, respectively. Therefore, they are recommended to use for climate change impact and adaptation studies in water resources management in the selected cities.