Spectrophotometry of comet Hartley-Good (1985l)

We present spectrophotometric studies of comet Hartley-Good (1985l) in the spectral region 3200–7000 Å. The emission features of molecules CN, CH, C₂, and C₃ are observed. The variation of the emission strength of different species has been studied as a function of heliocentric distance. The abundances (N) and production rates (Q) of the molecules are also estimated.     

Indian summer monsoon during the last two millennia

The monsoon is a large‐scale feature of the tropical atmospheric circulation, affecting people and economies in the world's most densely populated regions. Future trends due to natural variability and human‐induced climate changes are uncertain. Palaeoclimate records can improve our understanding of monsoon dynamics and thereby reduce this uncertainty. Palaeoclimate records have revealed a dramatic decrease in the Asian summer monsoon since the early Holocene maximum 9 ka BP. Here we focus on the last 2 ka, where some records indicate an increasing trend in the summer monsoon. Analysing Globigerina bulloides upwelling records from the Arabian Sea, we find the weakest monsoon occurred 1500 a BP, with an increasing trend towards the present. Copyright © 2010 John Wiley & Sons, Ltd.     

Prediction of subsurface water level change from satellite data

This study explores the potential for predicting the spatial variation in subsurface water level change with crop growth stage from satellite data in Thabua Irrigation Project, situated in the northern central region of Thailand. The relationship between subsurface water level change from pumping water to irrigate rice in the dry season and the age of the rice was analysed. The spatial model of subsurface water level change was developed from the classification using greenness or (normalized difference vegetation index NDVI) derived from Landsat 5 Thematic Mapper data. The NDVI of 52 rice fields was employed to assess its relationship to the age of the rice. It was found that NDVI and rice age have a good correlation (R² = 0·73). The low NDVI values (−0·059 to 0·082) in these fields were related to the young rice stage (0–30 days). NDVI and subsurface water level change were also correlated in this study and found to have a high correlation (Water level change (m day⁻¹) = 0·3442 × NDVI − 0·0372; R² = 0·96). From this model, the water level change caused by rice at different growth stages was derived. This was used to show the spatial variation of water level change in the project during the 1998–99 dry‐season cropping. This simple method of using NDVI relationships with water level change and crop growth stages proves to be useful in determining the areas prone to excessive lowering of the subsurface water level during the dry season. This could assist in the appropriate planning of the use of subsurface water resources in dry‐season cropping. Copyright © 2004 John Wiley & Sons, Ltd.     

The timing and magnitude of changes to Hortonian overland flow at the watershed scale during the post-fire recovery process

Extreme hydrologic responses following wildfires can lead to floods and debris flows with costly economic and societal impacts. Process-based hydrologic and geomorphic models used to predict the downstream impacts of wildfire must account for temporal changes in hydrologic parameters related to the generation and subsequent routing of infiltration-excess overland flow across the landscape. However, we lack quantitative relationships showing how parameters change with time-since-burning, particularly at the watershed scale. To assess variations in best-fit hydrologic parameters with time, we used the KINEROS2 hydrological model to explore temporal changes in hillslope saturated hydraulic conductivity (K_sh) and channel hydraulic roughness (n_c) following a wildfire in the upper Arroyo Seco watershed (41.5 km²), which burned during the 2009 Station fire in the San Gabriel Mountains, California, USA. This study explored runoff-producing storms between 2008 and 2014 to infer watershed hydraulic properties by calibrating the model to observations at the watershed outlet. Modelling indicates K_sh is lowest in the first year following the fire and then increases at an average rate of approximately 4.2 mm/h/year during the first 5 years of recovery. The estimated values for K_sh in the first year following the fire are similar to those obtained in previous studies on smaller watersheds (<1.5 km²) following the Station fire, suggesting hydrologic changes detected here can be applied to lower-order watersheds. Hydraulic roughness, n_c, was lowest in the first year following the fire, but increased by a factor of 2 after 1 year of recovery. Post-fire observations suggest changes in n_c are due to changes in grain roughness and vegetation in channels. These results provide quantitative constraints on the magnitude of fire-induced hydrologic changes following severe wildfires in chaparral-dominated ecosystems as well as the timing of hydrologic recovery.     

Some aspects of volcanic ash layers in the Central Indian Basin

Intercalated volcanic ash layers in two deep-sea sediment cores from the Central Indian Basin (CIB) are examined for the possibility of an in situ source of suboceanic volcanism. An in situ source has been predicated based on the bottom morphological structures and activation of seamounts during the geological past. The tentative correlation between depositional ages of the ash layer horizons and the period of global climatic cooling events reinforces the hypothesis that the suboceanic volcanic episode might have been initiated during the onset of glaciation.     

Evaluation on the change characteristics of ecosystem service in Dhanbad district of Jharkhand,India based on land use change

Ecosystem services (ESs) simply refer to those services conferred by Mother Nature for the survival of her offspring living within. But the provision of ESs is continuously affected by human activity and related changes like transformations in land use and land cover. The present study has been initiated to evaluate the pattern of landscape transformation and its impact on ecosystem service, along with estimating the per capita availability of ESs based on remotely sensed data in the Dhanbad district, Jharkhand, India. The result shows that the total ecosystem service value (ESV) loss of the district was $2251959.76 during 1990–2020. The highest loss of ESV was recorded due to the conservation of agricultural land to built-up area ($15884988.50) and vegetation cover on agricultural land ($14451545.01), while the increased vegetation cover on other types of land helped the district to gain back some balance over the loss. But in a smaller scale study, 5 out of the 8 spatial units are facing negative change in ESV, and unfortunately, they are altogether inhabited by more than 85% of the district's total population. That means the loss of ESV is greater where it needs to be more as per population. Moreover, the per capita ESs in the district decreased by 68.48%, while among the spatial units in Dhanbad it decreased the most (89.60%), which is a serious cause for worry in the future. Therefore, this study can contribute to the process of decision-making, proposing ecological conservation and sustainable development plans for the region.

     

An assessment of Dungale landslide using remotely piloted aircraft system (RPAS), ground penetration radar (GPR), and Slide & RS2 Softwares

Natural Hazards - In the present study, slope stability analysis was done using limit equilibrium method and finite element method of the Dungale landslide situated in the NW Himalaya along Tons...     

Geospatial modelling for sub-watershed prioritization in Western Himalayan Basin using morphometric parameters

Natural Hazards - Geographical information system and remote sensing are proven to be an efficient tool for locating water harvesting and recharge structures, groundwater potential, runoff,...     

FEA of Urban Rock Tunnels Under Impact Loading at Targeted Velocity

Geotechnical and Geological Engineering - This paper presents the effect of impact load and weathering of surrounding rockmass on the deformation behavior of urban underground structures. The FEM...