Integration of geospatial technologies with RUSLE for analysis of land use/cover change impact on soil erosion: case study in Rib watershed,north-western highland Ethiopia     

Desalew Meseret Moges  H. Gangadhara Bhat 《Environmental Earth Sciences》2017,76(22):765

In recent times, soil erosion interlocked with land use and land cover (LULC) changes has become one of the most important environmental issues in developing countries. Evaluation of this complex interaction between LULC change and soil erosion is indispensable in land use planning and conservation works. This paper analysed the impact of LULC change on soil erosion in the north-western highland Ethiopia over the period 1986–2016. Rib watershed, the area with dynamic LULC change and severe soil erosion problem, was selected as a case study site. Integrated approach that combined geospatial technologies with revised universal soil loss equation model was utilized to evaluate the spatio-temporal dynamics of soil loss over the study period. Pixel-based overlay of soil erosion intensity maps with LULC maps was carried out to understand the change in soil loss due to LULC change. Results showed that the annual soil loss in the study area varied from 0 to 236.5 t ha^?1 year^?1 (tons per hectare per year) in 1986 and 0–807 t ha^?1 year^?1 in 2016. The average annual soil loss for the entire watershed was estimated about 40 t ha^?1 year^?1 in 1986 comparing with 68 t ha^?1 year^?1 in 2016, a formidable increase. Soil erosion potential that was estimated to exceed the average soil loss tolerance level increased from 34.5% in 1986 to 66.8% in 2016. Expansion of agricultural land at the expense of grassland and shrubland was the most detrimental factor for severe soil erosion in the watershed. The most noticeable change in soil erosion intensity was observed from cropland with mean annual soil loss amount increased to 41.38 t ha^?1 year^?1 in 2016 from 26.60 in 1986. Moreover, the most successive erosion problems were detected in eastern, south-eastern and northern parts of the watershed. Therefore, the results of this study can help identify the soil erosion hot spots and conservation priority areas at local and regional levels.  相似文献   

Some salient features of the atmosphere observed over the north Bay of Bengal during BOBMEX     

G. S. Bhat 《Journal of Earth System Science》2003,112(2):131-146

This paper describes the near surface characteristics and vertical variations based on the observations made at 17.5‡N and 89‡E from ORV Sagar Kanya in the north Bay of Bengal during the Bay of Bengal Monsoon Experiment (BOBMEX) carried out in July–August 1999. BOBMEX captured both the active and weak phases of convection. SST remained above the convection threshold throughout the BOBMEX. While the response of the SST to atmospheric forcing was clearly observed, the response of the atmosphere to SST changes was not clear. SST decreased during periods of large scale precipitation, and increased during a weak phase of convection. It is shown that the latent heat flux at comparable wind speeds was about 25–50% lower over the Bay during BOBMEX compared to that over the Indian Ocean during other seasons and tropical west Pacific. On the other hand, the largest variations in the surface daily net heat flux are observed over the Bay during BOBMEX. SST predicted using observed surface fluxes showed that 1-D heat balance model works sometime but not always, and horizontal advection is important. The high resolution Vaisala radiosondes launched during BOBMEX could clearly bring out the changes in the vertical structure of the atmosphere between active and weak phases of convection. Convective Available Potential Energy of the surface air decreased by 2–3 kJ kg^-1 following convection, and recovered in a time period of one or two days. The mid tropospheric relative humidity and water vapor content, and wind direction show the major changes between the active and weak phases of convection.  相似文献   

Surface Characteristics Observed over the Central Tropical Indian Ocean During Indoex IFP99   总被引：3，自引：0，他引：3  

G. S. Bhat  Manu Anna Thomas  J. V. S. Raju  C. P. Chandrasekhara 《Boundary-Layer Meteorology》2003,106(2):263-281

The present study is based on the observations carried out over the IndianOcean from the Indian research vessel ORV Sagar Kanya during the intensive field phase of the Indian Ocean Experiment in January–March 1999. The study area spanned from 15°N to 20°S in the central Indian Ocean. Near surface variations and surface fluxes along the cruise track are presented. A comparison of near surface characteristics over the Indian Ocean and tropical west Pacific has been made. It is observed that the average difference between the sea surface temperature and air temperature at 10 m height was 0.7 °C over the study area, nearly half of that observed over the tropical west Pacific. A comparison between observed and NCEP reanalysissurface data has been made. We find good agreement between ship measured andNCEP reanalysis surface pressure, specific humidity and wind fields.On the other hand, surface air temperature in the reanalysis tends to be lowcompared to observations. The components of the net surface heat flux comparebetter in the north Indian Ocean than in the southern Indian Ocean.  相似文献   

Rainfall-induced landslide in the active frontal fold–thrust belt of Northwestern Himalaya,Jammu: dynamics inferred by geological evidences and Ground Penetrating Radar     

Yudhbir Singh  Ahsan Ul Haq  G. M. Bhat  S. K. Pandita  Arjun Singh  Rameshwar Sangra  Gulzar Hussain  S. S. Kotwal 《Environmental Earth Sciences》2018,77(16):592

Landslides are the most established geological hazards in the frontal fold–thrust belt of Northwestern Himalaya comprising of Siwaliks and Murree strata. The continuous rainfall from 2 to 6 September, 2014 caused a massive landslide at village Sadal in Udhampur district of Jammu and Kashmir state. The landslide occurred in the early morning of September 6, 2014, destroying entire Sadal habitation comprising 45 houses, and killing 41 people and more than 500 domestic animals. Google earth images of pre and post-landslide events along with the field measurements show the kinematics of upper and lower parts of the slide. Horizontal and vertical components of displacement and mode of failure suggest the landslide as of complex nature. The shallow subsurface geophysical imaging through Ground Penetrating Radar (GPR) survey shows the failure plane composed of friable mudstone bed underlain by massive mudstone and overlain by cross-bedded sandstone. The depth of debris material above the failure plane ranges from 6 m at Site S1a-b to 10 m at Site-S2b and 20 m at Site S3a. The velocity analysis of Site-3 shows four thick layers represented from bottom to surface by L1—sandstone (V?=?0.16 m/ns, travel time?=?356.36 ns), L2—mudstone (V?=?0.17 m/ns, travel time?=?288.48 ns), L3—massive mudstone (V?=?0.19 m/ns, travel time 220.68 ns), and L4—cross-laminated sandstone (V?=?0.20 m/ns, travel time?=?77.58 ns) overlaying the failure plane. The study shows the landslide occur along the western limb of a fold identified during the present work. We mapped an old landslide on the same limb which shows 5–6 m-thick subsurface debris material with thick rock fragments involved in the landslide process. The detailed geological and geophysical investigations suggest that both the landslides were triggered by extreme rain fall events.  相似文献   

Experimental Studies and its Application using PLAXIS-2D for Lithomargic Clay Stabilized by GBFS and Lime     

Mahesh Bhat  K.  Nayak  Sitaram 《Geotechnical and Geological Engineering》2021,39(7):4901-4915

Geotechnical and Geological Engineering - Lithomargic clay is found along the Eastern and Western coasts of Southern India. Presence of weak soils like lithomargic clay below the foundations, cause...  相似文献   

Quantification of groundwater–surface water interactions using environmental isotopes: A case study of Bringi Watershed,Kashmir Himalayas,India     

Nadeem A Bhat  Gh Jeelani 《Journal of Earth System Science》2018,127(5):63

Environmental isotopes including \({\updelta }^{18}\)O, \({\updelta }^{2}\)H and \(^{3}\)H of precipitation, streams and springs were determined in the mountainous Bringi catchment of Kashmir Himalaya, dominated by carbonate lithology. The isotopic signature of winter precipitation is reflected in stream and spring water in late spring and is, therefore, representative of snow melting. The spring waters in September bear the enriched isotopic signatures of summer rainfall. The strong correlation (\(r^{2} = 0.97\)) between the isotopic composition of streams and springs indicates the streams and springs either share similar catchments or the springs are recharged by the streams. Chloride mass balance and isotopic mass balance studies suggest that the surface recharge component averages 337.35 m\(^{3}\)/s, which is about 75% of total stream discharge during the high flow period. Similarly, the contribution of surface water to groundwater recharge during the low flow period averages 7.5 m\(^{3}\)/s, which is about 18.6% of total stream flow. Furthermore, the mean residence time of the springs calculated from the tritium decay equation is very short (<1 year). The residence time is longer for Kongamnag and short for Achabalnag, which is further supported by dye testing.  相似文献   

Malaysian Experiences of Peat Stabilization,State of the Art     

Hossein Moayedi  Ramli Nazir 《Geotechnical and Geological Engineering》2018,36(1):1-11

Peat has been considered as an organics remnant that suffers decomposition process throughout times under overburden pressure. Composition of peats normally consists of organics materials which sometimes exceed 75% specifically from woods that grows in marshes and places in conditions where deficiencies of oxygen exist. Usually peat area related with swampy and normally a low shear strength region. High compressibility is significant and often related to problematic soil for construction purposes. In this article, extensive number of studies are reviewed to understand the behavior of the peat after being stabilized. New findings indicated that the peat contents differs from one location to another, thus inevitably gives different behavior. Many improvisation methods have been put forward such as chemical stabilization, cement stabilization, deep mixing and fiber reinforcement to name a few to enhance the strength properties of the peat. This is mainly for construction reliability purposes. However, the suitability of the ground improvement for peat thus depend on its fundamental properties and cost involve for any dedicated ground construction work. This paper review the properties of peat in Malaysia and reviewed recent development in the peaty soil stabilization in Malaysia. It is also compared the materials used for the peat stabilization and the expansive clay soils as the main two problematic soils.  相似文献   

Spatial Variability of Some Chemical and Physical Soil Properties in Bandipora District of Lesser Himalayas     

Mushtaq A. Wani  N. Shaista  Zahid M. Wani 《Journal of the Indian Society of Remote Sensing》2017,45(4):611-620

Soil is a suitable place for vegetation and plant growth. When this valuable resource is not preserved, shortage of food, erosion and damage of natural resources will be respected. Soil is a heterogeneous, diverse and dynamic system and investigation of its temporal and spatial changes is essential. In this paper spatial variability of some chemical and physical soil were investigated. Three hundred fifty eight soil samples were collected by systematic sampling strategy at 20 cm depth on a regular grid spacing of 500 × 500 m² under different vegetation cover and processed for analysis in the laboratory. Soil chemical and physical parameters including pH, electrical conductivity, organic carbon, available phosphorus, available nitrogen, available potassium, sulphur, calcium, magnesium and sodium were measured. After data normalization, classical statistical analysis was used to describe soil properties and geo-statistical analysis was used to illustrate spatial correlation of soil characteristics. By using interpolating techniques, spatial distribution of these properties were prepared. Results indicated that calcium and phosphorus had strong and weak spatial dependence, respectively.  相似文献   

A search for the millisecond pulsar in Cygnus X-3     

R. C. Rannot  C. L. Bhat  A. K. Tickoo  M. L. Sapru  V. K. Senecha  R. K. Kaul 《Astrophysics and Space Science》1994,219(2):221-229

Atmospheric Cerenkov data, recorded at Gulmarg, India, during the 2-year period 1988–1989 in the direction of Cygnus X-3, have been searched for the presence of a periodic pulsar modulation, employing both the Rayleigh power and the epoch-folding ( ²) techniques. No evidence is found for pulsations at either 12.59 ms or 9.22 ms, the two period values around which the detection of pulsed signals has been reported by three atmospheric Cerenkov groups, but not by at least two other groups, including one using a higher-sensitivity Cerenkov imaging telescope.  相似文献   

On the marine atmospheric boundary layer characteristics over Bay of Bengal and Arabian Sea during the Integrated Campaign for Aerosols,gases and Radiation Budget (ICARB)     

Denny P. Alappattu  D. Bala Subrahamanyam  P. K. Kunhikrishnan  K. M. Somayaji  G. S. Bhat  R. Venkatesan  C. B. S. Dutt  A. Bagavath Singh  V. K. Soni  A. S. Tripathi 《Journal of Earth System Science》2008,117(1):281-291

Detailed measurements were carried out in the Marine Atmospheric Boundary Layer (MABL) during the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) which covered both Arabian Sea and Bay of Bengal during March to May 2006. In this paper, we present the meteorological observations made during this campaign. The latitudinal variation of the surface layer turbulent fluxes is also described in detail.  相似文献