Abstract Three major problems in cave micrometeorology are analysed: the concept of the temperature of a cave and its phenomenology; the internal energy flows and consequent local entropy production; and a non-hydrostatic physical model of the underground convective air circulation. A cave’s temperature is rich in information, but it is often difficult to obtain because it requires experimental accuracies to be pushed beyond the reach of common external meteorological instruments to detect a variety of factors, such as thermal sedimentation, seasonal variations and the effects of external morphology. Energy flow has an essential role in estimating the sensitivity of a cave to external inputs. A model for evaluating the local entropy production is developed. Entropy seems to be the most basic parameter, explaining both the sensitivity of the environment and its tendency to form complex structures. Analysis of the second-order terms of convective air circulation is more complex than expected; nevertheless, only such an analysis is able to explain the behaviours (e.g. continuity in the airflow) that cannot be predicted by the first-order models.

Abstract The sensitivity of glacier mass balance (MB) in response to climatic perturbations has made it an important parameter of study from hydrological, climatological and glaciological point of view. To monitor the health of any glacier system, long-term MB observations are required. These observations among Himalayan glaciers are not available consistently and large glaciers are not often monitored for mass balance due to logistical challenges. One such glacier is the Gangotri, situated in the western Himalaya. In the present study an attempt is made to model the MB over the Gangotri glacier, the biggest glacier in the Ganga basin and also the point of origin of the River Ganges. The mass balance of the Gangotri glacier is estimated during the time period 1985–2014 using two different methods: ice-flow velocity; and energy balance modelling using regional model (REMO) outputs and in situ automatic weather station (AWS) data. The geodetic method is used for the nearby Dokriani glacier, where field-based MB measurements are available. MB of Gangotri glacier estimated for 2001–14 using the ice-flow velocity method is −0.92 ± 0.36 m w.e. a −1 ; for 2006–07, MB using AWS and Tropical Rainfall Monitoring Mission (TRMM) data with the energy balance modelling approach is −0.82 m w.e. a −1 ; and for 1985–2005, MB using REMO data with the energy balance modelling approach is −0.98 ± 0.23 m w.e. a −1 . Using the surface velocity method, it is estimated that the glacier lost 9% of its volume during the period 2001–14. The glacier vacated an area of 0.152 km 2 from the snout region, and retreated by 200 m in the last 14 years. MB values estimated for the Gangotri glacier from different methodologies are remarkably close, suggesting them to be suitable methods of MB estimation. TRMM, High Asia Refined (HAR-10) and Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of water resources (APHRODITE) data are used to estimate the precipitation over the glacier. The study suggests that the glacier-wide estimation of weather parameters needs to be improved for more accurate estimation of glacier mass balance. Supplementary material: The snow-covered area, for months Jan-Dec, obtained for Gangotri glacier using Landsat data and NDSI (normalized differencing snow index) for year 2014 is available at https://doi.org/10.6084/m9.figshare.c.3888091

Abstract We describe a time series of meteorological parameters and surface energy balance components of a seasonal snow cover from an automatic weather station (4863 m a.s.l., 32.28° N, 77.58° E), for a winter season from 1 December 2012 to 30 March 2013, located on a moraine close to the equilibrium line altitude of Chhota Shigri glacier, Himachal Pradesh, India. The analysis shows that for over 80% of the time in winter, the snow surface was at a cooling phase. During late winter however, the surface had some positive residual energy which induced some melt during peak hours of the day. The net all-wave radiation was mostly negative during winter because of the high reflective property of snow and reduced incoming longwave radiation due to low cloud. The sensible heat flux heats the surface at night and enhances the cooling during day. The latent heat flux is always negative, showing that the surface is losing mass through sublimation processes (−0.83 mm w.e./day). A correlation between the energy fluxes and temperature shows a distinct relationship between fluxes. A comparison between the two studies performed on- and off-glacier reveals a significant difference in some parameters. A higher value (−1.08 mm/day) of sublimation rate at 4863 m a.s.l. shows that a large amount of energy available at the surface was used in sublimation processes. A comparatively lower albedo, relative humidity and net longwave radiation and higher latent heat flux, wind speed and net shortwave radiation yield a distinctive surface energy balance, highlighting the need for a large number of stations at different zones to achieve a coherent picture of energy balance in the region.

Mima mounds, often associated with vernal pools, have historically been shrouded in genetic uncertainty. Nevertheless, emerging from the array of explanations proposed, a biological mechanism for mound formation has steadily gained strength. We use innovations in remote sensing and geomorphic modeling to develop a new approach to evaluate the microtopography. Using a digital elevation model created from LIDAR (light detection and ranging) data, morphometric values—average mound diameters, heights, slopes, and curvatures—were calculated across an 18 km 2 sector of a mound-pool region that covers an ancient river terrace near Merced, California. The terrain information was applied to a sediment transport model to estimate mound erosion and swale deposition rates. The mean net erosion rate was 38 cm kyr −1 , using a diffusion coefficient of 50 cm 2 yr −1 . At steady state, erosion must be balanced by a restorative upslope transport, and this estimate of erosion is comparable to observed rates of sediment mounding via pocket gopher burrowing (61 cm kyr −1 ). These data suggest that bioturbation may play a dominant role in maintaining Mima mound terrain. LIDAR measurements were also used to develop a model that approximates the energy required for the formation of Mima mounds (shearing, pushing, and uplifting soil) and their maintenance (counteractions to erosion). This energy estimate was compared to estimates of energy available to gopher populations in the region. Our results indicate that gophers have ample energy to build typical Mima mounds in as little as 100 years, thus strongly supporting a biotic mechanism of Mima mound development and maintenance.