Terrain Research Articles

Mapping urban heat islands in Pune, India: ecological impacts and environmental challenges

ABSTRACT Heat waves increasingly affect cities, amplifying the urban heat island (UHI) effect, often measured through land surface temperature (LST). In Pune, India, rapid urbanization between 2013 and 2022 has driven significant land use and land cover changes, with a staggering 89.24% increase in built-up areas and a decline of 991.4 km2 in vegetation cover. Using satellite remote sensing data processed via Google Earth Engine, this study reveals a pronounced rise in LST, with mean temperatures increasing from 27°C in 2013 to 36°C by 2022, and a notable expansion in regions experiencing temperatures between 25°C and 32°C. Additionally, N O 2 levels slightly rose, further stressing environmental conditions. Central Pune was identified as a high-risk zone for adverse climatic impacts, emphasizing the urgent need for ecological conservation, climate adaptation, and sustainable urban planning to mitigate the growing UHI effect amidst accelerating urbanization in Indian cities.

Possible transition from Silandic to Aluandic Andosols with acidification as evidenced by detailed profile investigation of two well-preserved forest Andosols in Japan

ABSTRACT In Japan, Andosols are one of the major soils and they occupy about 30% of the total land surface. Andosols with andic properties have been grouped into two distinct categories: Silandic and Aluandic, but their formation has not been well investigated with reliable soil analytical data and needs to be studied for systematic understanding. To clarify the formation process of Silandic and Aluandic Andosols, two soil profiles, collected from natural forest sites at Aya (Sil-A) and Shiiba (Alu-A) in Miyazaki Prefecture, Japan, were investigated in detail. The soil samples were taken from the soil profiles at a 5 cm interval to reveal the changes in chemical and mineralogical properties with depth. The smooth changes in soil acidity (pH(H2O), pH(KCl), and y1), carbon stock (total carbon and δ13C), cation retention properties (cation exchange capacity and base saturation), and mineralogical properties (pyrophosphate and acid-oxalate extractable iron, aluminum, and silicon) indicated that both soil profiles had been formed under well-preserved natural forests. Based on the analytical data, Sil-A was classified as a Silandic Andosol (World Reference Base for Soil Resources 2022: WRB 2022) and an Allophanic Andosol (The Fifth Committee for Soil Classification and Nomenclature 2017: FCSCN 2017), whereas Alu-A was classified as an Aluandic (0–30 cm)/Silandic (30–90 cm) Andosol (WRB 2022) and a Non-allophanic Andosol (FCSCN 2017). The changes in the chemical and mineralogical properties with high depth-resolution suggested that the allophanic material contents were increased with depth within 0 to 50 cm, and they were related with soil pH(H2O) in both soils. It was suggested that acidification had happened from upper layers, resulting in dissolution of the allophanic materials and formation of Al-humus complexes in both soils, and Alu-A would have been more deeply affected by this process than Sil-A. Therefore, the authors conclude that Silandic/Allophanic Andosols can be transformed into Aluandic/Non-allophanic Andosols with acidification, and the phenomenon is typically observed in upper layers and progresses to deeper layers.

Optimizing Topographic Boundary Conditions for East Pacific Climate Simulation

Abstract Overly smooth topography in general circulation models (GCMs) underestimates the blocking effect of the steep mountain ranges flanking the eastern Pacific. We explore the impact of this bias on common biases in Pacific climate simulation [i.e., the unrealistic cross-equatorial symmetry of near-surface winds, sea surface temperatures (SSTs), and precipitation] through sensitivity experiments with modified Central and/or South American topography in an atmosphere–ocean coupled GCM. Quantifying orographic blocking potential via the Froude number, we determine that an envelope topographic interpolation scheme best captures observed blocking patterns. Implementing envelope topography only in Central America reduced model biases as greater blocking of the trade winds warmed SST and enhanced convergence in the northeastern Pacific. Doing so additionally over the Andes improved the simulation of South Pacific circulation and the South Pacific convergence zone as stronger deflection of the westerlies intensified the South Pacific anticyclone. This mitigated convection biases in the southeast Pacific by increasing subsidence and cooling SST. However, remote impacts of the Andes exacerbated the dry bias in the northeast tropical Pacific, resulting in negligible improvement in the East Pacific double-ITCZ. We find that, due to the significant role of large-scale convergence in driving precipitation patterns, other model biases, such as cloud-radiative biases, may modulate the impact of altering topography. Our results highlight the importance of considering alternate methods for calculating model topographic boundary conditions, though the optimal interpolation scheme will vary with model resolution and the impact of topography on GCM biases can be sensitive to choices made in formulating parameterizations. Significance Statement In this study, we explore how the mountain ranges spanning Central and South America shape the climate of the Pacific by blocking large-scale midlatitude and tropical winds. We show that the height of these mountains is typically too low in climate models and that elevating them can improve patterns of rainfall, surface ocean temperatures, and near-surface winds in the Pacific. This is important because model biases in the Pacific climate limit their utility for understanding current and future climate variability. Improving the representation of blocking by mountains can thus be a simple method for reducing uncertainties in future climate projections.

Simulation of latent heat flux over a high altitude pasture in the tropical Andes with a coupled land surface framework.

Simulation of latent heat flux over a high altitude pasture in the tropical Andes with a coupled land surface framework.

Assessment of land use land cover change and its impact on variations of land surface temperature in Atlanta, USA

Assessment of land use land cover change and its impact on variations of land surface temperature in Atlanta, USA

Urban expansion-induced land use land cover changes and the subsequent changes in ecosystem service and land surface temperature in the central highland of Ethiopia

Urban expansion-induced land use land cover changes and the subsequent changes in ecosystem service and land surface temperature in the central highland of Ethiopia

Numerical modelling of the hydrodynamics driven by tidal flooding of the land surface after dyke breaching

Numerical modelling of the hydrodynamics driven by tidal flooding of the land surface after dyke breaching

Assessing modelled methane emissions over northern wetlands by the JULES-HIMMELI model.

Assessing modelled methane emissions over northern wetlands by the JULES-HIMMELI model.

Urban waterlogging risk assessment in Zhengzhou based on the coupling land surface hazard-pregnant features and underground pipe network operation characteristics

Urban waterlogging risk assessment in Zhengzhou based on the coupling land surface hazard-pregnant features and underground pipe network operation characteristics

Combined effects of urban morphology on land surface temperature and PM2.5 concentration across fine-scale urban blocks in Hangzhou, China

Combined effects of urban morphology on land surface temperature and PM2.5 concentration across fine-scale urban blocks in Hangzhou, China

Multiscale impacts of urban nature on land surface temperature over two decades in a city with cloudy and foggy climates

Multiscale impacts of urban nature on land surface temperature over two decades in a city with cloudy and foggy climates

Development of downscaling technology for land surface temperature: A case study of Shanghai, China

Development of downscaling technology for land surface temperature: A case study of Shanghai, China

Beyond land surface temperature: Identifying areas of daytime thermal discomfort in cities by combining remote sensing and field measurements

Beyond land surface temperature: Identifying areas of daytime thermal discomfort in cities by combining remote sensing and field measurements

Streamlining land surface model Initialization: Automated data retrieval for VELMA using HMS REST API and GDAL

Streamlining land surface model Initialization: Automated data retrieval for VELMA using HMS REST API and GDAL

Derivation and Validation of a Theoretical Canopy Interception Model Based on Raindrop Microphysical Processes

AbstractCanopy interception represents the initial phase of rainfall redistribution across the land surface and is crucial for hydrological and ecological processes. This study proposes a novel theoretical model of canopy interception based on the microphysical processes of raindrops within the canopy. The model incorporates physical parameters pertinent to canopy characteristics, such as the attachment retention coefficient and the pinning proportion coefficient. Both the basic and simplified model forms of canopy interception during rainfall events have been derived. Further elaborations of the model account for stem flow, the surface evaporation during rainfall, and other conditions. The model parameters are clearly defined, physically meaningful, and can be directly estimated using detailed canopy structure data. This estimation process is now more feasible than ever due to advances in high‐resolution lidar technology. Simulated rainfall experiments were conducted to validate the movement patterns of raindrops in the canopy, establish model parameters, validate the models' accuracy, and compare the applicability of the two model forms.

The impact of wide-graded debris flow on sediment-trap dams in the Tibetan Plateau: an experimental study

In the Tibetan Plateau, pronounced topographical relief (steep mountains and deep valleys) coupled with intense weathering processes generates highly fragmented slope surfaces, creating debris-flow source materials with exceptionally heterogeneous grain-size distributions. These conditions frequently produce debris flows that exhibit extraordinary impact forces which cause severe damage to sediment-trap dams. Through 27 sets of flume experiments that systematically varied the particle-size distribution ( d max ), bulk density ( γ ) and flume slope ( θ ), this study investigates the impact mechanisms of wide-graded debris flows on sediment-trap dams. The results demonstrate that debris-flow interactions with sediment-trap dams occur through three distinct phases: (1) impact run-up, (2) rotational backflow and (3) depositional back-silting. Lower bulk-density flows exhibited greater run-up heights and more pronounced phase differentiation. Measured impact forces ( F ) showed an inverse relationship with bulk density ( γ ↑→ F ↓), while displaying positive correlations with both slope gradient ( θ ↑→ F ↑) and maximum particle size ( d max ↑→ F ↑). This occurs because higher- γ flows experience increased internal shear resistance, resulting in a reduction in velocity. Steeper slopes enhance kinematic energy, while larger particles generate more concentrated momentum transfer during impact. Sensitivity analysis revealed that d max exerts dominant control over impact dynamics compared to γ and θ . These findings provide critical insights for sediment-trap dam design in high-altitude debris-flow mitigation systems.

Impacts of leaf traits on vegetation optical properties in Earth system modeling

Quantifying surface energy and carbon budgets is essential for projecting Earth’s climate. Earth System Models (ESMs) typically simulate land surface processes based on plant functional types (PFTs), neglecting the diversity of plant functional traits or characteristics (PFCs; e.g., chlorophyll content and leaf mass per area). Here, we demonstrate substantial differences in modeled leaf optical properties (LOP) and surface albedo between traditional PFT-based and PFC-based approaches, particularly in tropical and boreal forests. We configure the canopy radiative transfer scheme in the Community Earth System Model using PFC-based LOP. This new configuration produces lower shortwave surface albedo in the tropics but higher albedo in boreal regions (>5 W m−2 radiative flux differences), and a weaker tropical but stronger boreal carbon sink. Through land-atmosphere coupling, the PFC-based configuration further alters atmospheric processes, leading to different temperature, cloud cover, and precipitation patterns. Our findings highlight the need to move beyond traditional PFT-based approaches in ESMs.

Salinity Barriers to Manage Saltwater Intrusion in Coastal Zone Aquifers During Global Climate Change: A Review and New Perspective

Climate change will have a significant impact on saltwater intrusion in coastal aquifers between now and 2150. Global sea levels are predicted to rise somewhere between 0.5 and 1.8 m. To mitigate sea level rise, coastal aquifers will require intensive management to avoid inland migration of seawater that could impact water supplies. In addition to reducing pumping of freshwater, the construction and operation of salinity barriers will be required in many locations. Eleven types of salinity barriers were investigated, including physical barriers (curtain wall and grout curtains), infiltration canals filled with freshwater paralleling the coastline, injection of freshwater (treated surface water or wastewater), pumping or abstraction barriers, mixed injection and abstraction barriers, combined abstraction, desalination, and recharge (ADR), ADR hybrid barriers using various water sources including desalinated water and treated wastewater, compressed air barriers, aquifer storage and recovery dual use systems, biofilm barriers, and clay swelling or dispersion barriers. Feasibility of the use of each salinity barrier type was evaluated within the context of the most recent projections of sea level changes. Key factors used in the evaluation included local hydrogeology, land surface slope, water use, the rate of sea level rise, technical feasibility (operational track record), and economics.

Integrating GIS and AHP for Forest Fire Risk Mapping in Kailali, Nepal

Forest are the Earth’s predominant geographical phenomena distributed throughout the world and provide essential ecosystem services and products that benefit both humans and wildlife. The sustainability of the forest resources can be seriously affected by the forest fire in the dry regions covered with fire sensitive trees species. The risk of the forest fire mainly depends on the various factors such as vegetation type, topographical features, climatic parameters, socio-economic factors. Geographic Information System (GIS) and Remote Sensing (RS) technologies are frequently used for the monitoring, detection, and management of forest fires. Seven parameters: land cover, elevation, slope, aspect, land surface temperature (LST), and proximity to settlement and road were compared with each other and pair wise matrix was formed. The weight of each parameters was determined by using AHP technique. Then by using the raster calculator weighted-overlay analysis was performed to determine the final forest fire risk zone. The forest fire risk zone was categorized into five classes; very high-risk zone, high risk zone, moderate risk zone, low risk zone, and very low risk zone. The result indicated that there is a very high risk of forest fire in about 30.78%, a high risk in 34.06%, a moderate risk in 22.45%, a low risk in 9.87% and very low risk in 2.84% of total area of Kailali district.

U–Pb zircon ages constrain the Miocene age of hydrothermal activity in the iron mining Hüttenberg-Waitschach district (Austria), faulting and landscape evolution in the Eastern Alps

Abstract U–Pb zircon dating usually yields precise timing of high-temperature magmatic and/or metamorphic events. Less common is the potential to date alteration events. Here, we report an unexpected example of a mainly Miocene hydrothermal alteration and ore mineralization event in the Austroalpine mega-unit of the Eastern Alps, which occurred closely related to the landscape surface formation, and which dates the latest hydrothermal stages in the iron mining Hüttenberg-Waitschach district. There, mining was in operation in the last 2500 years, and the famous, particularly strong Mn-rich Ferrum Noricum was mined there during the Roman Empire. Near to the latest exploration galleries, U–Pb zircon dating of an amphibolite from the Plankogel Complex, which hosts the iron ore, yields a Cambrian age (512.6 ± 1.8 Ma) for magmatic zircon crystallization. Magmatic zircons are overprinted by mostly concordant zircons during two alteration stages, according to cathodoluminescence textures and age, between 26 to 20 Ma and 19 to 15 Ma. These zircon rims are interpreted to relate to hydrothermal activity and ore precipitation along fault zones, which are a distant expression of the Görtschitz Valley fault zone and formation of the Miocene piedmont alluvial fan during extension in front of the rapidly uprising Saualpe Block. There, the base of the Miocene Waitschach Gravel is exposed ~ 100 m above the investigated amphibolite. As the base of the Miocene land surface is at an elevation of ca. 900 m, subsequent incision of the Görtschitz Valley along the Görtschitz Valley fault indicates minimum 140 m surface uplift since Early Miocene indicating a significant change from west-directed to south-directed drainage. Graphical abstract