Land Change Research Articles

Alterations in Hydrological Responses under Changing Climate and Land Use/Land Cover across Contrasting Agroecological Environments: A Case Study on the Chemoga Watershed in the Upper Blue Nile Basin, Ethiopia

We analyzed hydrological responses to changing climate and land use/land cover (LULC) for the past (1985–2020) and future (2021–2080) in the Chemoga watershed of the Upper Blue Nile Basin. The watershed comprises four agroecological environments: Moist Kolla, Moist Weyna Dega, Moist Dega, and Wet Wurch. Past and projected LULC changes under business-as-usual (BAU) and land conservation (LC) scenarios were utilized. Climate projections from 2021 to 2080, under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5), were downscaled from Global Climate Models. Utilizing the Soil and Water Analysis Tool, we assessed impacts on mean annual surface runoff (SR) and evapotranspiration (ET). Maximum and minimum temperatures increased significantly in the past and future climate scenarios, with a significant rainfall increase observed under SSP5-8.5. Historical trends revealed a 16.6% increase in SR and 7% in ET from 1983–2002 to 2003–2020. Under BAU LULC with the SSP2-4.5 (SSP5-8.5) climate scenario, SR increased by 24% (26.1%) and ET by 3.1% (4.4%) from 2003–2020 to 2021–2050, followed by a subsequent SR rise of 13.7% (14.0%) and ET increase of 6.0% (5.7%) from 2021–2050 to 2051–2080. Conversely, the LC LULC with SSP2-4.5 (SSP5-8.5) resulted in a 5.3% (4.2%) SR decrease and ET increase of 9.7% (11.3%) from 2003–2020 to 2021–2050 and a further SR decrease of 1% (0.7%) and 6.1% (6.9%) ET increase from 2021–2050 to 2051–2080. The Moist Kolla agroecology experienced the highest SR increase due to vegetation clearances for commercial farming. Meanwhile, the LC scenario indicated substantial decreases in SR and marginal increases in ET in the Moist Weyna Dega agroecology due to forest restoration on steep slopes. Overall, SR showed greater sensitivity to LULC changes, while ET was more responsive to climate changes. The results emphasize considering diverse agroecological contexts for effective water resource management under changing climate and LULC scenarios.

A non‐grain production on cropland spatiotemporal change detection method based on Landsat time‐series data

AbstractGlobal food security is being threatened by the reduction of high‐quality cropland, extreme weather events, and the uncertainty of food supply chains. The globalization of agricultural trade has elevated the diversification of non‐grain production (NGP) on cultivated land to a prominent strategy for poverty alleviation in numerous developing nations. Its rapid expansion has engendered a multitude of deleterious consequences on both food security and ecological stability. NGP in China is becoming very common in the process of rapid urbanization, threatening national food security. To better understand the causal mechanisms and enable governments to balance food security and rural development, it is crucial to have a clear understanding of the spatiotemporal dynamics of NGP using remote sensing. Yet knowledge gaps remain concerning how to use remote sensing to track human‐dominated or ‐induced long‐term cultivated land changes. Our study proposed a method for detecting the spatiotemporal evolution of NGP based on Landsat time‐series data under the Google Earth Engine platform. This approach was proposed by (1) obtaining the union of cultivated lands from multiple landcover products to minimize the cultivated land omission, (2) constructing multi‐index dynamic trend rules for 3 representative types of NGP and obtaining results at the pixel level, while adopting the continuous change detection and classification algorithm to Landsat time series (1986–2022) to determine when the most recent change occurred, (3) minimizing the noise by object‐oriented land use–land cover classification and mode filter approaches, and (4) mapping the spatiotemporal distribution of NGP. The proposed methodology was tested in Jiashan, located in Zhejiang Province (eastern China), where NGP is widespread. We achieved a high overall accuracy of 95.67% for NGP type detection and an overall accuracy of 85.26% for change detection of time. The results indicated a continued increasing pattern of NGP in Jiashan from 1986 to 2022, with the cumulative percentage of NGP increasing from 0.02% to 20.69%. This study highlights the utilization of time‐series data to document essential NGP information for evaluating food security in China and the method is well‐suited for large‐scale mapping due to its automatic manner.

Management of Watersheds as a Planning, Monitoring and Evaluation Zone Unit for the Development of the City: A Case Study of Karangmumus Watershed at Samarinda City, East Kalimantan Province, Indonesia

The changing land use affects the social and economic characteristics and environmental issues in a watershed. To support sub-watershed management, land use scenarios and the level of community involvement must be improved. This research is a study to analyse and evaluate the condition of the Karangmumus watershed covering 365.25 km2 which is mostly located in Samarinda City, the capital of East Kalimantan Province. Research was conducted with various sources of data analysed using descriptive quantitative methods. In assessing the condition of a watershed, it is absolutely necessary to have debit data and other data to support the analysis and evaluation. In reality, currently the quantity and quality of flow data is still far from expected. This is due to the difficulties that cause the flow data collection process can not be done in all places, but only in certain watersheds. In the watershed monitoring carried out, there are still obstacles, one of which is the continuity of observation.

Comparison of comprehensive benefits of land-use systems under multi- and single-element governance

Considering the decline in the ecosystem service value (ESV) caused by rapid urbanization, China has recently conducted large-scale comprehensive ecological governance of “mountain, water, forest, field, lake and grass”; however, theoretical analyses of such systematic governance are lacking. This study compares the effects of multi- and single-element governance from a systematic perspective. This study proposes a hierarchical model integrating land-use simulation and comprehensive benefit evaluation based on remote sensing data of land-use in the Hebei Province, China, between 2000 and 2019. It compares the ESV and subtotal ecological-economic product (SEP), which reflects comprehensive benefits under ten governance scenarios. The results revealed significant urban expansion, amounting to 7516 km2, with significant changes in cultivated land and grassland. The ESV increased from 89.2 to 134.6 billion USD from 2000 to 2019, with regulatory and support services as the primary types of ecosystem services. With single-element governance, the ESV and SEP of water area governance were higher than those of woodland and cultivated land. With multi-element governance, the ESV and SEP of governance focusing on water areas were higher than those focusing on woodland and cultivated land. Moreover, multi-element ecological governance was found to be superior to single-element governance. Ecological governance of water areas and woodland ensured higher comprehensive benefits, while avoiding risks caused by excessive changes in land-use structure. The lower ESV and ESP of other multi- and single-element governance were primarily owing to two types of conversion: 1) grassland to woodland and cultivated land, and 2) water areas to cultivated land. Therefore, it is necessary to focus on the core elements of regional ecosystems and implement comprehensive ecological governance, address practical problems of land consolidation and ecological governance, and appropriately introduce market forces to realize the operation and management of the entire process and life cycle. These findings could provide a scientific reference for other regions in China and other developing countries implementing ecological governance practices.

The Evolution of Agrarian Landscapes in the Tropical Andes.

Changes in land-use practices have been a central element of human adaptation to Holocene climate change. Many practices that result in the short-term stabilization of socio-natural systems, however, have longer-term, unanticipated consequences that present cascading challenges for human subsistence strategies and opportunities for subsequent adaptations. Investigating complex sequences of interaction between climate change and human land-use in the past-rather than short-term causes and effects-is therefore essential for understanding processes of adaptation and change, but this approach has been stymied by a lack of suitably-scaled paleoecological data. Through a high-resolution paleoecological analysis, we provide a 7000-year history of changing climate and land management around Lake Acopia in the Andes of southern Peru. We identify evidence of the onset of pastoralism, maize cultivation, and possibly cultivation of quinoa and potatoes to form a complex agrarian landscape by c. 4300 years ago. Cumulative interactive climate-cultivation effects resulting in erosion ended abruptly c. 2300 years ago. After this time, reduced sedimentation rates are attributed to the construction and use of agricultural terraces within the catchment of the lake. These results provide new insights into the role of humans in the manufacture of Andean landscapes and the incremental, adaptive processes through which land-use practices take shape.

Monitoring spatiotemporal changes in land use/land cover and its impacts on ecosystem services in southern Zambia

Ecosystems play a vital role in human well-being, yet the widespread loss of ecosystem services due to human activities, including agricultural expansion and deforestation, remains a significant concern. Despite the wealth of research highlighting the importance of ecosystem conservation in Zambia, a critical gap exists in understanding the interplay between the conservation of ecosystem services and the socio-economic needs of local communities. This study presents a comparative analysis of ecosystem services in two distinct landscapes within southern Zambia: the protected area of Kafue National Park (KNP) and the agricultural landscape of Kalomo district between 2000–2020. Employing a combination of quantitative and qualitative methods, we evaluate the impacts of land/use and land cover (LULC) changes on selected ecosystem services, with a particular focus on carbon storage and the habitat quality of the trumpeter hornbill. The results of the comparison indicate that: (1) the Kalomo district has suffered from extensive land conversion, with forest changing to cropland, while KNP was well protected from encroachment, with forest area increasing over time; (2) carbon stocks and the habitat quality of trumpeter hornbills continually decreased in the Kalomo district but improved in KNP; (3) Kalomo district has suffered rapid environmental degradation due to an imbalance between economic development and environmental conservation, while strict enforcement in KNP has preserved ecosystems. The findings underscore the importance of integrated and inclusive land-use planning and natural resource governance for maintaining and enhancing ecosystem services in Zambia. To progress towards landscape management that is both sustainable and equitable, aligning with the objectives of the Global Biodiversity Framework, it is proposed that a comprehensive approach be adopted in the region. This approach should encompass a more thorough consideration of local livelihood requirements, as well as the wider political-economic and social factors at play.

Rob Flood Control on the North Coast of Java (Study on coastal areas of Pekalongan and Semarang)

Flooding on the coasts of Pekalongan and Semarang, North Coast of Java (Pantura), has become a severe problem for the Indonesian government. Factors causing the flood are rainfall, climate, land subsidence and rob, river conditions, tidal influence, poorer areas, land change, inappropriate flood control, damage to flood control buildings, excessive groundwater utilization, inappropriate flood management, river sedimentation, reduced water catchment areas, and runoff floods. Therefore, there is a need for an appropriate handling study to deal with these problems. This research aimed to determine the achievements of coastal flood control on the North Coast of Java. Data was collected through a literature review for secondary data, field studies for primary data, in-depth interviews with relevant stakeholders, and observation. The results showed that handling Rob flooding in coastal Pekalongan focuses on four locations: Bremi River, Meduri River, Mrican pump house, and Silempeng. Rob flood handling methods on the Pekalongan coast include the construction of concrete barriers with corrugated sheet pile (CCSP), compacted soil embankments with bamboo mattress reinforcement, and submersible pumping machines at the Mrican pump house. In comparison, rob flood management in coastal Semarang focuses on the Sringin and Tenggang rivers. The flood handling methods conducted are the provision of pumps, construction of Rob embankments and retention ponds, normalization, drainage improvements, and interconnection channels. However, handling coastal flooding needs a comprehensive and sustainable follow-up.

Study of coastal land change in sand mining activities in Bandar Batauga Village, South Buton Regency, Indonesia

Study of coastal land change in sand mining activities in Bandar Batauga Village, South Buton Regency, Indonesia

Analyzing land use and land cover change in the Pra River Basin: A multi-tool approach for informed decision-making

Quantifying land use and land cover change (LULCC) is essential for addressing societal challenges and conserving ecosystems. This study focuses on analyzing the dynamics of five LULC classifications at a 30 m spatial resolution using satellite imagery from Landsat, coupled with various tools (Google Earth Engine, ArcMap, QGIS, and IDRISI SELVA) and indicators such as the Bare Soil Index (BSI). Historic time series data (2007, 2015, and 2023) were utilized to assess land change and predict future scenarios (2030 and 2063) using (CA) Markov models of the land change modeler (LCM). With a kappa coefficient and overall accuracy of 95 %, and 93 % respectively, our analysis reveals that LUC has significantly impacted nearly a third of the Pra River Basin (PRB) land area in two decades (2007–2023) after the launch of Agenda 2063 (The Africa We Want), with projected future impacts doubling under a business-as-usual (BAU) scenario. Geographical variations in LULC change processes are evident, with farmland abandonment, deforestation, and agricultural expansion observed predominantly in the northwestern region (Upper Pra, Anum, and Birim) of the basin. A 25 % increment of cultivated/farmland from 2007 to 2015 and a further 8 % in 2023. The northeast region (Upper and Lower Offin, Twifo Praso) faces deforestation and encroachment along riverbanks, along with built-up expansion due to mining activities. The northern region (Oda and Upper Pra) experiences exponential built-up and bare land increment. Accelerated phases of LULC change are attributed to factors such as mining (illegal and small-scale), agricultural production, migration, and population increment highlighting the influence of economic activities on land use dynamics. The concept gives a hybrid approach of using multi-tools in offering critical awareness of the state of the river system and encouraging the need for informed decision-making towards the anthropogenic impacts on the basin through effective management of LULC classes.

Spatial-temporal analysis of urban climate dynamics in major Hungarian cities

Increasing heatwaves are making cities and their populations more vulnerable, parallel to urban sprawl and the aging population in Hungary. The increasing number of hot days is predicted to worsen urban climate anomalies at the local scale, which, in parallel with changing land use patterns, may contribute to a significant increase in vulnerability to heatwaves. Local stakeholders and decision-makers need to understand the critical role of spatiotemporal land use—land cover (LULC) patterns and urban climate aspects to address relevant challenges for urban development. The current literature does not contain a synthesis analysis of major Hungarian cities that includes urban climate and sustainability findings hand by hand; therefore, this study aims to analyze LULC patterns, urban hotspots and surface urban heat island effects. In addition, the Normalized Difference Vegetation Index (NDVI) was determined as an important indicator for assessing the health and density of green spaces in major Hungarian cities from 2006 to 2018 using remote sensing data. Our results show that each city experienced significant urban sprawl, while above-average NDVI areas decreased over time. The average increase in the share of built-up areas was 1.3% from 2006 to 2018, while the calculated average decline in agricultural areas was 2%, so the expansion of residential areas and artificial areas is not the only driving force of this shrinking trend in agricultural areas. Furthermore, we found that urban hotspots are generally concentrated in industrial areas and represent new spaces of heat islands on the outskirts of cities. Székesfehérvár has the most intense industrial heat islands, with the largest proportion of urban hotspots (approximately 3.5% of the total area) concentrated in industrial zones. Our study contributes to uncovering inter-urban processes of land use patterns and urban climate issues in major Hungarian cities, moreover revealing sustainability-related issues from a lock-in perspective.

The analysis of changes in land management indicators over 30 years considering the food security of the country

The overarching aim of ensuring the country's food security is providing of the country's population with wholesome, quality-assured and available agriproduct, raw materials and food in volumes that ensure rational food consumption criteria. One of the central objectives of ensuring food security, whether external and internal conditions change or not, is the sustainable development of agriproduct, raw materials and food, sufficient to provide food sovereignty predicated on the principle of research-backed planning. Using the example of some regions of the Russian Federation, a look-back study of agricultural land use and changes in land management activities over a 30-year period was carried out, and the measures for rational land use organization.

2020年京津冀1 km格网沟渠密度数据集

As important ecological corridors in farmland ecosystems, ditches are not only important for collecting water, holding water as flowing channels, but also valuable for biodiversity conservation as various wetland ecological systems. They play an important role in purifying water quality and maintaining biodiversity. Ditch density is an important indicator of ditch structure in a certain area, directly revealing ditch configuration and farmland irrigation and drainage capacity. Taking the national land change survey data in 2020 as the data source, we extracted the skeleton lines of irrigation canals and ditches by using software, and calculated the density of 1km grid ditches in Beijing, Tianjin and Hebei in 2020 by using km grid production tools. This dataset can be used for research on rural planning, farmland irrigation and drainage convenience, farmland quality evaluation, farmland assets evaluation, etc.

Land-Use Change Dynamics in Areas Subjected to Direct Urbanization Pressure: A Case Study of the City of Olsztyn

Urbanization is one of the most visible symptoms of global changes. This process has been driven by the evolution of life on Earth, and it gradually modifies the structure of land use. Urban development is the most apparent indicator and measure of urbanization. The demand for vacant land and sustainable spatial development plans require new methods that support decision-making in the process of changing land use in suburban areas. The aim of this study was to describe a methodology for identifying and localizing urban development boundaries with the use of fuzzy set theory, to evaluate the degree of urbanization, and to analyze the dynamics of land-use changes in areas subjected to direct urbanization pressure with the use of photogrammetric data for 2005, 2010, 2017, and 2022. A case study was conducted in the Polish city of Olsztyn. The study’s results determined the degree of urbanization of the areas in the [0, 1] range, as well as the dynamics of change in each of the twenty-four adopted forms of land use. The results indicate that the proposed methods are useful for identifying the rate and direction of urbanization, and can be applied to optimize and counterbalance the development of settlements and infrastructure.

Dynamics of Population and Land Use towards Sustainable Development in Patna Planning Area

Abstract: This study examines the impact of population growth on the land use pattern of Patna Planning Area, in the context of urban geography. Patna, the capital city of Bihar state in India, has experienced significant population growth over the past few decades, leading to changes in its land use pattern. The objectives of this research include analyzing the historical population growth trends in Patna, identifying the key factors that have contributed to this growth, and assessing its impact on land use. The study takes into account various factors such as residential, industrial, commercial, and agricultural land use, as well as the infrastructural developments associated with population growth. To achieve these objectives, both primary and secondary data sources are utilized. Primary data is collected through surveys, interviews, and observations, while secondary data is obtained from existing literature, government reports, and demographic databases. The findings of this study reveal that the population growth in Patna has led to a changing land use pattern. The expansion of residential areas and the conversion of agricultural land into residential and commercial zones are noted as significant transformations. Additionally, industrial growth has resulted in the emergence of new industrial zones and the conversion of agricultural land into industrial areas in the suburbs. Furthermore, it is observed that population growth has put pressure on infrastructure such as transportation, sewage and water supply systems, leading to the need for their expansion and development. This study highlights the need for urban planning and policies to accommodate the growing population while ensuring sustainable land use.

Runoff variation in midstream Hei River, northwest China: Characteristics and driving factors analysis

Study regionThe midstream of the Hei River Basin (HRB). Study focusThe study investigated the changes in hydrological elements at different time scales in the basin from 1982 to 2020. We used the Budyko coupled balance equation to quantitatively assess the contributions of climate change and human activity-induced land surface changes to runoff during different periods. In addition, the driving factors of flow consumption within the basin were analyzed using wavelet coherence and generalized additive model (GAM). New hydrological insights for the regionPrior to 2001, there was a significant decrease in annual-scale runoff in the midstream. After that, a partial recovery was observed due to the influence of the Ecological Water Transfer Project (EWTP), while the NDVI trend exhibited an opposite pattern. The study indicates that human-induced modification of the underlying surface is the primary driving factor for the decrease in runoff, with land surface factors contributing 84.69% and 65.27% to the runoff reduction during two periods of change, respectively. Further research on the driving forces of runoff consumption reveals that vegetation cover and climate factors jointly regulate the variations in runoff consumption in the midstream, with multifactor effects surpassing those of individual factors, and NDVI emerges as the predominant controlling factor for runoff consumption. Moreover, all anthropogenic factors exhibit a high explanatory power for runoff consumption.

Predicting the impacts of urban development on urban thermal environment using machine learning algorithms in Nanjing, China

The urban thermal environment undergoes significant influences from changes in land use/land cover (LULC). This article uses CA-ANN and ANN algorithms to forecast LULC and changes in the urban thermal environment in Nanjing for the years 2030 and 2040. It investigates the interplay between LULC changes, land surface temperature (LST), and the urban thermal field variance index (UTFVI). The findings reveal that urban land exhibited a significant expansion trend from 2000 to 2019, reaching 1083.43 km2 in 2019. The forecast indicates that urban land may increase by 8.79% and 10.92% by 2030 and 2040, respectively. Conversely, vegetation and bare land may decrease. The LST is likely to continue to rise, accompanied by a significant expansion of the high temperature range and a contraction of the low temperature range. By 2030 and 2040, the area with LST<20 °C is likely to decrease by 2.17% and 3.19%, while the area with LST>30 °C is likely to expand by 5.68% and 8.08%, respectively. The UTFVI area of urban land may decrease at none and middle levels but may notably expand at stronger and strongest levels. The areas with UTFVI at none, weak, and middle levels show a declining trend, while the increase in UTFVI at the strong level may exceed 46.29% and the strongest level of UTFVI may continue to expand. This study offers new insights into urban sustainable development and thermal environment governance.

Changing land and labour relations on cocoa farms in Sefwi, Ghana: Continuity and change

Ever since the late 1880s when cocoa began to be grown commercially in Ghana, land and labour has been mobilized to expand the area under cocoa trees and cultivate the crop. The first cocoa farmers ingeniously used and adapted existing social norms for land acquisition and recruitment of labour from both the extended family and from migrants. The resulting development of cocoa was a remarkable story of African innovation and enterprise that made the then Gold Coast one of the most prosperous parts of Africa by the mid-twentieth century. We look at how land and labour has been mobilized for cocoa in Sefwi, western Ghana, from the start of cocoa growing in the region in the 1940s through to 2019. We ask what current norms are, how they have evolved, and why changes to them have been made. Changes in land and labour relations in the area have not followed the linear evolutionary theory of land tenure change neither have they remained as unique immutable customary structures. We note a flexible, reversible and highly pragmatic logic in tandem with the ruling exigencies that account for patterns of change over time.

Investigating Land Cover Changes and Their Impact on Land Surface Temperature in Khyber Pakhtunkhwa, Pakistan

Restoration of degraded land is a significant concern in the 21st century in order to combat the impacts of climate change. For this reason, the provisional government of Khyber Pakhtunkhwa (KPK), Pakistan, initialized a Billion Tree Tsunami Project (BTTP) in 2013 and finished it in 2017. Although a few researchers have investigated the land use transitions under BTTP in the short term by merging all the vegetation types into one, analysis of the long-term benefits of the project and future persistence were missing. Furthermore, the previous studies have not discussed whether the prime objective of the BTTP was achieved. Considering the existing gaps, this research mainly involves analyzing (i) fluctuations in the green fraction by employing a land change modeler (LCM), along with the spatial location of gain-loss and exchange analysis using a high-resolution dataset (GLC30); (ii) forest cover changes under the influence of the BTTP; (iii) impacts of green fraction changes towards land surface temperature (LST) by utilizing the less-explored technique of curve fit linear regression modeling (CFLR); and finally, (iv) assessing the persistence of the NDVI and LST trends by employing the Hurst exponent. Research findings indicate that as an output of BTTP, despite the government’s claim of increasing the forest cover by 2%, a significant gain of grassland (3904.87 km2) was observed at the cost of bare land. In comparison, the overall increase in forest cover was only 0.39%, which does not satisfy the main objective of this project. On the other hand, the CFLRM-based actual contributions of land cover change (LCC) transition to LST indicate a significant decline in LST in the areas with gains in green fraction for both grassland and forest. At the same time, an increase was observed with reverse transitions. Although the results appear positive for climatic impacts in the short term, the HURST model-based persistence analysis revealed that the spatial locations of increasing vegetation and decreasing LST trends fall under the weakly persistent category, therefore these trends may not continue in the near future. Despite some positive impact on LST attributed to the green fraction increase, this project cannot be regarded as a complete success due to its failure to achieve its prime objective.

Holocene Sea-level impacts on Venice Lagoon's coastal wetlands

Venice Lagoon (Italy), the largest wetland in the Mediterranean basin, is extremely vulnerable to variations in relative sea level (RSL) which is locally defined by an average rising rate of about 2.5mm per year, resulting from both sea-level change and vertical land movements. The environmental pressures stemming from projected higher RSL rising rates will have a profound impact on Venetian coastal ecosystems with a significant loss of wetlands partly due to a drastic reduction of salt marsh habitats. To understand how changes in marine influence could create such ecological upheaval in the near future, and fully remodel these coastal salt marshes, we reconstructed 5650 years of RSL rise history and land subsidence impacts on ecosystem dynamics during the Holocene transgression of Venice Lagoon. We show that the evolution of ecosystems mainly mirrors the gradual intrusion of salt water that progressively reshaped the coastal vegetation by turning the area into salt lagoon habitats. Before marine influence became dominant, the area was mainly fed by substantial freshwater supplies allowing the development of a diversified alluvial vegetation. Environmental pressures increased markedly about 6800–6600 years ago when seawater began to significantly influence the area, affecting marsh-swamp ecosystems. These marine inputs promoted the spread of halophytic and salt-tolerant vegetation types which laid the foundations for what would become the current salt marsh habitats. Venice Lagoon serves as a stark reminder of how rising sea levels, accompanied by increased saltwater intrusion into freshwater habitats and adjacent lands, can drastically alter and reshape pre-existing ecosystems. The lagoon's long-term ecological record indicates that contemporary fluctuations in RSL pose a substantial ecological threat, potentially culminating in a major upheaval of aquatic habitats in the near future.

A synthesis of Global Streamflow Characteristics, Hydrometeorology, and Catchment Attributes (GSHA) for large sample river-centric studies

Abstract. Our understanding and predictive capability of streamflow processes largely rely on high-quality datasets that depict a river's upstream basin characteristics. Recent proliferation of large sample hydrology (LSH) datasets has promoted model parameter estimation and data-driven analyses of hydrological processes worldwide, yet existing LSH is still insufficient in terms of sample coverage, uncertainty estimates, and dynamic descriptions of anthropogenic activities. To bridge the gap, we contribute the synthesis of Global Streamflow characteristics, Hydrometeorology, and catchment Attributes (GSHA) to complement existing LSH datasets, which covers 21 568 watersheds from 13 agencies for as long as 43 years based on discharge observations scraped from the internet. In addition to annual and monthly streamflow indices, each basin's daily meteorological variables (i.e., precipitation, 2 m air temperature, longwave/shortwave radiation, wind speed, actual and potential evapotranspiration), daily–weekly water storage terms (i.e., snow water equivalence, soil moisture, groundwater percentage), and yearly dynamic descriptors of the land surface characteristics (i.e., urban/cropland/forest fractions, leaf area index, reservoir storage and degree of regulation) are also provided by combining openly available remote sensing and reanalysis datasets. The uncertainties in all meteorological variables are estimated with independent data sources. Our analyses reveal the following insights: (i) the meteorological data uncertainties vary across variables and geographical regions, and the revealed pattern should be accounted for by LSH users; (ii) ∼6 % watersheds shifted between human-managed and natural states during 2001–2015, e.g., basins with environmental recovery projects in northeast China, which may be useful for hydrologic analysis that takes the changing land surface characteristics into account; and (iii) GSHA watersheds showed a more widespread declining trend in runoff coefficient than an increasing trend, pointing towards critical water availability issues. Overall, GSHA is expected to serve hydrological model parameter estimation and data-driven analyses as it continues to improve. GSHA v1.1 can be accessed at https://doi.org/10.5281/zenodo.8090704 and https://doi.org/10.5281/zenodo.10433905 (Yin et al., 2023a, b).