Journal articles | John Mohd Wani | Cryosphere Research

The Tricky Water Energy Budget of Freezing Soil: A Thermodynamic Framework for Understanding Phase Changes

Wed, 19 Aug 2026 00:00:00 +0000

In press

Accepted in Geotechnical and Geological Engineering on 19 August 2026. The DOI and full text will be linked here once the paper is published.

Summary

Water in soil does not all freeze at 0 °C: it freezes over a range of temperatures, largest pores first, and some of it never freezes at all. Three mechanisms keep that water liquid — capillarity, dissolved solutes and adsorption on mineral surfaces — and each is usually described with a model drawn from a different literature. This paper derives all three from a single expression for the chemical potential of pore water, links the soil water retention curve to the soil freezing characteristic curve through the generalised Clausius–Clapeyron relation, and closes the energy budget with enthalpy as the single conserved variable. The framework is theoretical; its assumptions are stated as a timescale criterion that can be checked for a given soil and forcing.

An integrated computational framework for high-dimensional parameter optimization in coupled hydro-thermal permafrost modelling

Mon, 20 Apr 2026 00:00:00 +0000

Abstract

Frozen ground behavior in high latitudes is controlled by coupled subsurface moisture and temperature. Modelling these multi-physics processes is a significant challenge in computational geoscience due to highly non-linear phase changes and the problem of identifying vertical soil stratigraphy and parameterizing vertical heterogeneity within the 1D column. We developed a novel integrated computational framework coupling the physically based 3.0 with a MATLAB control environment, applied to three boreholes (Meteo, Brzydal, Lola) near the Polish Polar Station, Hornsund, Svalbard (2017–2025). This framework automates the modelling lifecycle, enabling high-dimensional parameter identification. We utilized Particle Swarm Optimization to calibrate 101 parameters per borehole, while Global Sensitivity Analysis (Morris method) identified key drivers. Our analysis revealed that model performance, and thus the simulated ground thermal regime, was controlled by hydraulic-thermal coupling, specifically van Genuchten retention parameters (α, n) and saturated water content. Deep permafrost temperatures were simulated with high accuracy during both calibration and validation (RMSE < 0.2 °C). Near-surface temperatures exhibit larger errors, with RMSE values of 0.84–1.63 °C. At the Lola borehole, near-surface RMSE approximately doubled during validation. These results reflect the inherent challenges of numerically capturing the rapid, non-linear phase-change transitions within the active layer, the zone critical for foundation and ground structural integrity. This work provides a robust and reproducible computational tool for the parameterization and evaluation in cold-regions.

30-years (1991-2021) Snow Water Equivalent Dataset in the Po River District, Italy

Tue, 04 Mar 2025 00:00:00 +0000

Abstract

This paper presents a long-term snow water equivalent dataset in the Po River District, Italy, spanning from 1991 to 2021 at daily time step and 500 m spatial resolution partially covering the mountain ranges of Alps and Apennines. The data has been generated using a hybrid modelling approach integrating the hydrological modelling conducted with the physically-based GEOtop model, preprocessing of the meteorological data, and assimilation of in-situ snow measurements and Earth Observation snow products to enhance the quality of the model estimates. A rigorous quality assessment of the dataset has been performed at different control points selected based on reliability, quality, and territorial distribution. The point validation between simulated and observed snow depth across control points shows the accuracy of the dataset in simulating the normal and relatively high snow conditions, respectively. Additionally, satellite snow cover maps have been compared with simulated snow depth maps, as a function of elevation and aspect. 2D Validation shows accurate values over time and space, expressed in terms of snowline along the cardinal directions.

Permafrost estimation model in Upper Indus Basin

Sat, 23 Sep 2023 00:00:00 +0000

Abstract

Remotely sensed topo-climatic factors, potential incoming solar radiation (PISR), land surface temperature (LST), topographic wetness index (TWI), Surface emissivity, and elevation, and machine learning techniques are used for mapping the spatial distribution of permafrost in the Tso Kar, a sub-basin of Upper Indus Basin (UIB) in Leh, Ladakh (UT). This schematic model is employed to identify remotely sensed parameters which are crucial in assessing permafrost extent over the study region. It is followed by the application and tuning of several machine learning models to deliver an expected accuracy in terms of permafrost classes demarcated over the study region based on literature. Results show that the PISR, LST and TWI are the most significant remotely sensed parameters affecting the permafrost and associated processes. Above 5000 m a.s.l., the proportion of permafrost in the study catchment is higher. Synergistic use of remote sensing image processing and machine learning techniques together provide mapping of permafrost over the region, which is elusive so far.

Permafrost in the Upper Indus Basin: An active layer dynamics

Wed, 29 Mar 2023 00:00:00 +0000

Abstract

Permafrost in the Upper Indus Basin (UIB) in Ladakh, India, is a critical water source and is less studied. Identifying permafrost and its characteristics is a crucial knowledge gap in the UIB. Thus, understanding the permafrost active layer dynamics is critical and essential due to its implications on regional hydrology, infrastructure stability, and disaster occurrence. For this purpose, an experimental site is prepared with 11 plots having two near-surface ground temperature loggers each, i.e., 22 in total, in the upper Ganglass catchment, a sub-region of the UIB, Ladakh. The permafrost active layer thickness characteristics and its thaw progression are simulated using the 1-D GEOtop model with forcing from these 22 loggers from 2016 to 2020. The snow days are calculated using the near-surface ground temperature. The simulation results show no permafrost at 4727 m a.s.l. consistently, whereas all the plots above 4900 m a.s.l. show permafrost active layer thickness, in particular, up to 4 m at 4942 m a.s.l. Permafrost characteristics significantly differ between a warmer (colder) year with low (high) snow. The mean surface offset of the catchment ranges between −0.01° and 5.5°C. These findings on permafrost and associated periglacial processes will provide a critical knowledge base for the stability of high-elevation infrastructure, glacial lakes, regional hydrology and climate, particularly for water.

The representation of summer monsoon rainfall over northeast India: assessing the performance of CORDEX-CORE model experiments

Tue, 17 Jan 2023 00:00:00 +0000

Abstract

In this study, the performance of the latest high-resolution CORDEX-CORE model simulations is assessed with respect to the corresponding gridded Indian Meteorological Department (IMD) and ERA5 observations in representing the monsoon rainfall over northeast India during the historical period (1979–2005). Three different RCM model simulations (COSMO, RegCM4.7, and REMO) downscaled from the global data over the South Asian CORDEX domain are used in this study. Their corresponding RCM ensembles using boundary conditions from ERA-Interim re-analysis and CMIP5 GCMs and a combined ensemble of all the RCMs were also evaluated to assess their performance. The analysis shows that the COSMO model experiments resemble closer to both the observations while comparing with the other two RCMs. With respect to IMD and ERA5 observations, the COSMO model experiments show moderate wet bias across the study area. In contrast, the RegCM model experiments show very wet bias and the REMO model experiments show more dry bias across a significant part of the study region. Quantitatively, in comparison to IMD, the COSMO suite of models shows a slight overestimation ranging between 7 and 13%, and with ERA5, an underestimation of about 14 to 18% is observed. In comparison to both observations, the REMO model experiments underestimate (15 to 50%), whereas the RegCM model experiments overestimate (15 to 80%) the monsoon rainfall. Overall, these model experiments replicate the monsoon rainfall over the study region but with biases that differ spatially.

Hanging glacier avalanche (Raunthigad–Rishiganga) and debris flow disaster on 7 February 2021, Uttarakhand, India: a preliminary assessment

Sun, 03 Jul 2022 00:00:00 +0000

Abstract

A catastrophic debris flow in the Rishiganga and Dhauliganga rivers in Uttarakhand, India, on 7 February 2021 left a trail of disaster. Around 100–150 people lost their lives according to Uttarakhand Chief Secretary statement given to ANI news portal, two hydropower projects were badly damaged and a bridge across the Rishiganga River was washed off in the event. Study shows that the debris flow is caused due to detachment of 0.59 km2 right lobe of a hanging glacier and resultant ice-rock avalanche. This right lobe of the glacier was located over a mountain slope having an average slope of 35° at 4700–5555 m a.s.l. and travelled 12.4 km before hitting the infrastructure projects. Role of precipitation, snow cover, land surface temperature, and permafrost processes were investigated for identifying causes of the event. Since 2012, monsoon precipitation and mean annual land surface temperature (LST) showed significant increasing trend. Snow cover during monsoon months showed increasing trend and September, October and November experienced decreasing trend at glacier elevations. Mean annual LST increased from − 0.3 °C in 2012 to a peak of 0.4 °C in 2016. Central lobe of the glacier advanced during this period and eventually fell off in 2016 suggesting that the LST warming forced reduction of frictional drag at the interface facilitating it advancement and eventual dislodgement. Permafrost modelling suggests warm permafrost below 50 m and conditions favourable for intense frost cracking up to 10–15 m. At ~ 40 m depth, the delayed response of 2012–2016 warming produced peak positive temperature conditions by December and probably facilitated the formation of thin film of water at the deeper layers acting as a lubricant for glacier sliding. It is also suggested that the increase in summer precipitation might have forced thickening of the accumulation area and thereby increasing the shear stress for sliding of the glacier. It is proposed that the recent change in the weather conditions in the region is primarily responsible for this event through geological, glaciological, and permafrost processes. Flood modelling study suggests a flood volume of ~ 10 MCM generating 24.5 m flow depth at the bridge site with 12.7 m/s flow velocity. The event highlighted the need for improved monitoring of the cryosphere areas of the Himalaya to capture the early warning signs for better preparedness.

The surface energy balance in a cold and arid permafrost environment, Ladakh, Himalayas, India

Tue, 18 May 2021 00:00:00 +0000

Abstract

Recent studies have shown the cold and arid trans-Himalayan region comprises significant areas underlain by permafrost. While the information on the permafrost characteristics of this region started emerging, the governing energy regime is of particular interest. This paper presents the results of a surface energy balance (SEB) study carried out in the upper Ganglass catchment in the Ladakh region of India which feeds directly into the Indus River. The point-scale SEB is estimated using the 1D mode of the GEOtop model for the period of 1 September 2015 to 31 August 2017 at 4727 m a.s.l. elevation. The model is evaluated using field-monitored snow depth variations (accumulation and melting), outgoing long-wave radiation and near-surface ground temperatures and showed good agreement with the respective simulated values. For the study period, the SEB characteristics of the study site show that the net radiation (29.7 W m−2) was the major component, followed by sensible heat flux (−15.6 W m−2), latent heat flux (−11.2 W m−2) and ground heat flux (−0.5 W m−2). During both years, the latent heat flux was highest in summer and lowest in winter, whereas the sensible heat flux was highest in post-winter and gradually decreased towards the pre-winter season. During the study period, snow cover builds up starting around the last week of December, facilitating ground cooling during almost 3 months (October to December), with sub-zero temperatures down to −20 ∘C providing a favourable environment for permafrost. It is observed that the Ladakh region has a very low relative humidity in the range of 43 % compared to e.g. ∼70 % in the European Alps, resulting in lower incoming long-wave radiation and strongly negative net long-wave radiation averaging ∼−90 W m−2 compared to −40 W m−2 in the European Alps. Hence, land surfaces at high elevation in cold and arid regions could be overall colder than the locations with higher relative humidity, such as the European Alps. Further, it is found that high incoming short-wave radiation during summer months in the region may be facilitating enhanced cooling of wet valley bottom surfaces as a result of stronger evaporation.

Single-year thermal regime and inferred permafrost occurrence in the upper Ganglass catchment of the cold-arid Himalaya, Ladakh, India

Mon, 10 Feb 2020 00:00:00 +0000

Abstract

Cold-arid regions of the trans-Himalaya in the Indian Himalayan Region (IHR) is suspected to have a significant area of permafrost. However, information on the ground thermal regime of these permafrost areas is so far not available. This study bridge this knowledge gap by analysing the sub-surface thermal regime of selected sites in the Ganglass catchment, Ladakh range. Near surface ground temperature data recorded during September 2016 to August 2017 using 24-miniature temperature data loggers distributed across 12 plots and covering an elevation range of 4700-5612 m a.s.l. are used in this study. Permafrost characteristics including plausible ranges of thermal offset, active-layer thickness and mean annual ground temperature at 10 m depth were estimated by driving a one-dimensional heat conduction model. Two statistical models were used to map first order estimates of permafrost area in this 15.4 km2 catchment. Study suggest permafrost occurrence at all sites above 4900 m a.s.l. with active-layer thickness ranging from 0.1 to 4.2 m and the mean annual ground surface temperature ranging from between -10.0 and -0.85 °C for these sites. MAAT at these sites range from -4.1 to -8.9 °C and the surface offsets vary from -1.1 to 3.9 °C. Estimated thermal offset range from -0.9 to 0 °C. Both statistical models show comparable results and suggest 95% mean permafrost cover in the catchment above 4727 m a.s.l. These results strongly indicate existence of significant permafrost areas across the high elevations of the cold-arid regions of IHR. So far, permafrost processes are not considered for assessing present and future estimates of water and regional climate and as a causative factor for disasters like debris flows and landslides in the region. This study highlight the need for greater research efforts on Himalayan permafrost to have a comprehensive understanding of Himalayan cryosphere.

Assessment of Trends and Variability of Rainfall and Temperature for the District of Mandi in Himachal Pradesh, India

Tue, 03 Oct 2017 00:00:00 +0000

Abstract

Climate variability, particularly, that of the annual air temperature and precipitation, has received a great deal of attention worldwide. The magnitude of the variability of the factors changes according to the locations. The present study focuses on detecting the trends and variability in the annual temperature and rainfall for the district of Mandi in Himachal Pradesh, India. This study used annual and monsoon time series data for the time period 1981-2010 and modified the Mann-Kendall test and Sen’s slope estimator in analyzing the problem. The results of the analysis indicate that the annual maximum temperature (TMX) and annual minimum temperature (TMN) for the period of 30 years have shown an increasing trend, whereas the monsoon’s maximum and minimum temperatures have shown a decreasing trend, although it is statistically not significant. The amount of annual rainfall does not show any significant trend, but the monsoonal rainfall has shown an increasing trend that is also statistically not significant. The resulting Mann-Kendall test statistic (Z) and Sen’s slope estimate (Q) of all the parameters studied indicate that changes are occurring in the magnitude and timing of the precipitation and temperature events at the Mandi station.