Impact of vegetation on the simulation of seasonal monsoon rainfall over the Indian subcontinent using a regional model
Surya K Dutta 1 , Someshwar Das 1, ∗,SCKar 1 , U C Mohanty 2 and P CJoshi 3
1 National Centre for Medium Range Weather Forecasting, Noida, UP 201 307, India.
2 Centre for Atmospheric Science, IIT, Delhi, India.
3 Space Application Centre, ISRO, Ahmedabad 380 015, India.
∗e-mail: somesh07@yahoo.com somesh03@gmail.com

Abstract: The change in the type of vegetation fraction can induce major changes in the local e ffects such as local evaporation,surface radiation,etc.,that in turn induces changes in the model simulated  outputs.The present study deals with the
effects of vegetation in climate modeling over the Indian  region using the MM5 mesoscale model.The main objective of the present study is to investigate the impact of vegetation dataset derived from SPOT satellite by ISRO (Indian Space Research Organization)versus that of USGS (United States Geological Survey)vegetation dataset on the simulation of the Indian summer monsoon.The present study has been conducted for five monsoon seasons (1998 –2002),giving emphasis over the two contrasting southwest monsoon seasons of 1998 (normal)and 2002 (de ficient).

The study reveals mixed results on the impact of vegetation datasets generated by ISRO and USGS on the simulations of the monsoon.Results indicate that the ISRO data has a positive impact on the simulations of the monsoon over northeastern India and along the western coast.The MM5- USGS has greater tendency of overestimation of rainfall.It has higher standard deviation indicating that it induces a dispersive e ffect on the rainfall simulation.Among the five years of study,it is seen that the RMSE of July and JJAS (June –July –August –September)for All India Rainfall is mostly lower for MM5-ISRO.Also,the bias of July and JJAS rainfall is mostly closer to unity for MM5-ISRO.The wind fields at 850 hPa and 200 hPa are also better simulated by MM5 using ISRO vegetation.The synoptic features like Somali jet and Tibetan anticyclone are simulated closer to the veri fication analysis by ISRO vegetation.The 2 m air temperature is also better simulated by ISRO vegetation over the northeastern India,showing greater spatial variability over the region. However,the JJAS total rainfall over north India and Deccan coast is better simulated using the USGS vegetation.Sensible heat flux over north-west India is also better simulated by MM5-USGS.


The interaction of large scale and mesoscale environment leading to formation of intense thunderstorms over Kolkata Part I: Doppler radar and satellite observations
P Mukhopadhyay 1, ∗, M Mahakur 1 and H AKSingh 2
1 Forecasting Research Division, Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road,
Pune 411 008, India.
2 India Meteorological Department, Mausam Bhawan, Lodi Road, New Delhi 110 003, India.
∗e-mail: mpartha@tropmet.res.in

Abstract: The weather systems that predominantly a ffect the eastern and northeastern parts of India during  the pre-monsoon summer months (March,April and May)are severe thunderstorms,known as Nor ’westers.The storms derive their names from the fact that they frequently strike cities and towns in the southern part of West Bengal in the afternoon from the north-west direction while traveling far from its place of genesis over the Bihar plateau.The storms are devastating in nature particularly due to strong (gusty)winds,heavy rains and hails associated with it.Although these storms are well known for its power of causing damages,studies on them are relatively few due to their small  size and sparse network of observations.To address this important issue,the evolution of two Nor ’westers of 12 March and 22 May 2003 over Kolkata is studied in detail in this paper using hourly Doppler weather radar (DWR)observations and high resolution Meteosat-5 imageries.In addition,supporting meteorological reports are used to find the large scale conditions that in fluence the moisture convergence and vertical wind shear.The genesis of both the storms is found to be over Bihar –Jharkhand region and beyond the range of the DWR.The satellite observations are found to be useful in identifying the location and initiation of the storms.The movements of the storms are captured by the DWR estimated vertical cross-section of re flectivities.The Doppler estimate shows that the 12 March storm had a vertical extent of about 10 –12 km at the time of maturity and that of 22 May reaching up to 18 km signifying deep convection associated with these events.The genesis, maturity and dissipation are well brought out by the hourly DWR and satellite imageries.The DWR observations suggest that the systems move at a speed of 20 –25 m/s.The DWR estimated precipitation shows a detailed spatial distribution around Kolkata with several localized zones of heavy rain and this is found to be well supported by the nearby station observations.This study establishes that DWR observations along with hourly satellite imageries are able to capture the evolution of Nor ’westers.The study also shows that the composite DWR-satellite information is a reliable tool for nowcasting the location,time and path of movement of Nor ’westers.Based on these observations,a conceptual model of the Nor ’wester is proposed.


A study of lightning activity over land and oceanic regions of India
Asha Nath 1 , G K Manohar 2 ,K K Dani 1 and P C S Devara 1
1 Indian Institute of Tropical Meteorology,Pune 411 008,India.
2 Formerly,Indian Institute of Tropical Meteorology,Pune 411 008,India.

Abstract: Monthly variations of lightning activity over typical land and oceanic regions of India were  examined using satellite data (OTD)for a 5-year period (1995 –1999).It is noted that the nature of variation between surface air maximum temperature (Tmax ,thunderstorm days (Th n ,and lightning flash count over ER and WR showed remarkable correspondence and sensitivity with each other on monthly time scale.As we move out of winter season and enter the monsoon season,via pre-monsoon season,the WR undergoes cooling relative to the ER in the range 0.1 –1 .◦C.As a result,WR experiences reduction of thunder days and lowering in flash count. This decrease in Tmax Th n and flash count over WR may also be associated with relatively small values of Tøw and CAPE in comparison with similar values over ER during the monsoon sea-son.Our observation of associated reduction in Th n and lightning count per 1 ◦C cooling in surface air maximum temperature suggests reduction of ∼3 . thunderstorms per station and 73 flashes.Comparison of lightning flashes between pairs of coastal,oceanic,arid-zone,hilly,and island stations reveals distinct relationship between climate regime and intensity of lightning activity.We may conclude the results of this study by saying that the overhead lightning activity is a clear re flection of the status of the underlying ground-earth properties.A close and continuous monitoring of lightning activity may be considered as a need of present day scientific studies.


On the diurnal ranges of Sea Surface Temperature (SST) in the north Indian Ocean
S S C Shenoi 1,3, ∗, N Nasnodkar 1 ,GRajesh 2 , K Jossia Joseph 2 ,
I Suresh 1 and A M Almeida 1
1 National Institute of Oceanography (Council of Scientific and Industrial Research), Dona Paula,
Goa 403 004, India.
2 National Institute of Ocean Technology (Ministry of Earth Sciences), Pallikarani, Chennai 600 100, India.
3 Present address: Indian National Centre for Ocean Information Services (Ministry of Earth Sciences),
Hyderabad, India.
∗e-mail: shenoi@incois.gov.in

Abstract: This paper describes the variability in the diurnal range of SST in the north Indian Ocean using in situ measurements and tests the suitability of simple regression models in estimating the diurnal range.SST measurements obtained from 1556 drifting and 25 moored buoys were used to determine the diurnal range of SSTs.The magnitude of diurnal range of SST was highest in spring and lowest in summer monsoon.Except in spring,nearly 75 –80%of the observations reported diurnal range below 0 .5 ◦C.The distributions of the magnitudes of diurnal warming across the three basins of north Indian Ocean (Arabian Sea,Bay of Bengal and Equatorial Indian Ocean)were similar except for the  differences between the Arabian Sea and the other two basins during November –February  (winter monsoon)and May.The magnitude of diurnal warming that depended on the location of temperature sensor below the water level varied with seasons.In spring,the magnitude of diurnal warming diminished drastically with the increase in the depth of temperature sensor.The diurnal range estimated using the drifting buoy data was higher than the diurnal range estimated using moored buoys fitted with temperature sensors at greater depths.

A simple regression model based on the peak solar radiation and average wind speed was good enough to estimate the diurnal range of SST at ∼1 .0 m in the north Indian Ocean during most of the seasons except under low wind-high solar radiation conditions that occur mostly during spring. The additional information on the rate of precipitation is found to be redundant for the estimation of the magnitude of diurnal warming at those depths.


Seasonal variation in the biochemical composition of red seaweed (Catenella repens Catenella repens Catenella repens) from Gangetic delta, northeast coast of India
Kakoli Banerjee 1 ,RajrupaGhosh 1, ∗, Sumit Homechaudhuri 2 and Abhijit Mitra 1
1 Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, India.
2 Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700 019, India.
∗e-mail: rajrupa14@gmail.com

Abstract: The biochemical composition of red seaweeds,Catenella repens was investigated in this present study along with subsequent analysis of relevant physico-chemical variables.In this study, the relationship between the nutritive components of this species and the ambient environ- mental parameters was established.Protein content varied from 2 . ± 0 .of dry weight (stn.3)to 16 . ± 0 .of dry weight (stn.1)with highest values during monsoon.The protein levels were positively correlated with dissolved nitrate content and negatively cor- related with water temperature (except stn.3)and salinity.Carbohydrate content of this species varied signi ficantly (p <.during pre-monsoon between stations and the values showed positive relationship with salinity and surface water temperature.In contrast to carbo- hydrate,lipid concentration was lowest in values and varied very slightly between seasons and stations.Astaxanthin content of the seaweed species was greater in pre-monsoon than monsoon and post-monsoon in all the selected stations.Compared with the three seasons, samples of red seaweed collected in pre-monsoon has high carbohydrate –astaxanthin in con- trast to protein –lipid which showed high values during monsoon.Statistical analysis computed among the environmental and biochemical parameters suggests the potential role played by the abiotic parameters on biosynthetic pathways of seaweed.This paper also highlights the in flu- ence of the nutritional quality of water that can be used for mass cultivation of Catenella repens.


Groundwater flow modelling of Yamuna–Krishni interstream, a part of central Ganga Plain Uttar Pradesh
Izrar Ahmed and Rashid Umar
Department of Geology,Aligarh Muslim University,Aligarh 202 002,India.
∗e-mail:rashidumar@redi ffmail.com

Abstract: Groundwater is a major source of water for agricultural and domestic requirements in western Uttar Pradesh.Due to increasing agricultural requirements the abstraction of groundwater has increased manifold in the last two-to-three decades.The quaternary alluvium hosts the aquifer in the region.The study area forms a part of Yamuna –Krishni inter fluve.Although the area hosts potential aquifers these have been adversely a ffected by poor management.For effective ground water management of a basin it is essential that a careful water balance study should be carried out. Keeping this in mind groundwater flow modelling was attempted to simulate the behaviour of the  flow system and evaluate the water balance.The groundwater flow modelling was carried out.The horizontal flows,seepage losses from unlined canals,recharge from rainfall and irrigation return flows were applied using di fferent boundary packages available in Visual MODFLOW,Pro 4.1. The river aquifer interaction was simulated using the river boundary package.Hydraulic conduc- tivity values were applied to speci fic zones and these ranged from 9.8 to 26.6 m/day.Recharge due to rainfall and irrigation returns were assigned to respective zones.Pumping rates of 500 m 3 / 1000 m 3 /1500 m 3 /2000 m 3 / and 2500 m 3 / were applied to appropriate areas of the  model to simulate areas of stress.The zone budget shows a water balance de ficit for the period June 2006 to June 2007.The total recharge to the study area is 160.21 million m 3 (Mcum).The groundwater draft through pumping is of the order of 233.56 Mcum,thus leaving a de ficit balance of − 73 . Mcum.The sensitivity of the model to input parameters was tested by varying the para- meters of interest over a range of values,monitoring the response of the model and determining the root mean square error of the simulated groundwater heads to the measured heads.These analyses showed that the model is most sensitive to hydraulic conductivity and recharge parameters.Three scenarios were considered to predict  aquifer responses under varied conditions of groundwater bstraction.


Estimation of snow cover distribution in Beas basin, Indian Himalaya using satellite data and ground measurements
H S Negi 1 ∗,A V Kulkarni 2 and B SSemwal 3
1 Snow &Avalanche Study Establishment,Chandigarh 160 036,India.
2 Space Applications Centre,Ahmedabad,380 015,India.
3 H N B Garhwal University,Srinagar Garhwal,246 174,India.
∗e-mail:negi −hs@yahoo.com

Abstract: In the present paper,a methodology has been developed for the mapping of snow cover in Beas basin,Indian Himalaya using AWiFS (IRS-P6)satellite data.The complexities in the mapping of snow cover in the study area are snow under vegetation,contaminated snow and patchy snow. To overcome these problems,field measurements using spectroradiometer were carried out and re flectance/snow indices trend were studied.By evaluation and validation of  different topographic correction models,it was observed that,the normalized di fference snow index (NDSI)values remain constant with the variations in slope and aspect and thus NDSI can take care of topography e ffects.Di fferent snow cover mapping methods using snow indices are compared to find the suitable mapping technique.The proposed methodology for snow cover mapping uses the NDSI (estimated using planetary re flectance),NIR band re flectance and forest/vegetation cover information.The satellite estimated snow or non-snow pixel information using proposed methodology was validated with the snow cover information collected at three observatory locations and it was found that the algorithm classify all the sample points correctly,once that pixel is cloud free.The snow cover distribution was estimated using one year (2004 –05)cloud free satellite data and good correlation was observed between increase/decrease areal extent of seasonal snow cover and ground observed fresh snowfall and standing snow data.


Analytical solutions of one-dimensional advection – di ffusion equation with variable coe fficients in a finite domain
Atul Kumar, Dilip Kumar Jaiswal and Naveen Kumar
Department of Mathematics,Faculty of Science,Banaras Hindu University,Varanasi 221 005,India.
∗e-mail:naveen@bhu.ac.in nks −1953@yahoo.co.in

Abstract: Analytical solutions are obtained for one-dimensional advection –di ffusion equation with variable coe fficients in a longitudinal finite initially solute free domain,for two dispersion problems.In the first one,temporally dependent solute dispersion along uniform flow in homogeneous domain is studied.In the second problem the velocity is considered spatially dependent due to the inhomo- geneity of the domain and the dispersion is considered proportional to the square of the velocity. The velocity is linearly interpolated to represent small increase in it along the finite domain.This analytical solution is compared with the numerical solution in case the dispersion is proportional to the same linearly interpolated velocity.The input condition is considered continuous of uniform and of increasing nature both.The analytical solutions are obtained by using Laplace transforma- tion technique.In that process new independent space and time variables have been introduced. The e ffects of the dependency of dispersion with time and the inhomogeneity of the domain on the solute transport are studied separately with the help of graphs.


Detection of sub-basaltic sediments by a multi-parametric joint inversion approach
Ajay Manglik* Saurabh K Verma and K H Singh 1
National Geophysical Research Institute (Council of Scientific & Industrial Research), Hyderabad 500 606, India.
1 Present Address: GEST UMBC @ Planetary Geodynamics Laboratory, NASA Goddard Space Flight Center,
Greenbelt, Maryland, USA.
∗e-mail: ajay@ngri.res.in

Abstract: In many parts of the world sedimentary horizons with potential for hydrocarbon are located below flood basalt provinces.However,the presence of high velocity basaltic overburden makes delineation of sediments di fficult due to the low velocity layer problem.Electrical and electromagnetic methods have been used in such scenarios because of the good electrical conductivity contrast between basalts and underlying sediments.However,mapping of the target sediments becomes di fficult when the layer is thin as the data errors due to inherent noise lead to equivalent solutions.To tackle such di fficult situations,a joint inversion scheme incorporating seismic re flection and refraction, magnetotelluric and deep electrical resistivity datasets is presented.E fficacy of the scheme is tested for a model comprising a thin sedimentary layer sandwiched between a thick basalt cover and a granitic basement.The results indicate that the parameters of the target sedimentary layer are either poorly resolved or equivalent solutions are obtained by the inversion of individual datasets. Joint inversions of seismic re flection (RFLS)and refraction (RFRS),or DC and  MT dataset pairs provide improved results and the range of equivalent solutions is narrowed down.Combination of any three of the above datasets leads to further narrowing of this range and improvements in mean model estimates.Joint inversion incorporating all the datasets is found to yield good estimates of the structure.Resolution analysis is carried out to appraise estimates of various model parameters obtained by jointly inverting di fferent combinations of datasets.


Consolidation of a poroelastic half-space with anisotropic permeability and compressible constituents by axisymmetric surface loading
Sarva Jit Singh 1 ∗, Raman Kumar 2 and Sunita Rani 2 ∗∗
1 Department of Mathematics,University of Delhi,South Campus,New Delhi 110 021,India.
2 Department of Mathematics,Guru Jambheshwar University of Science and Technology,Hisar 125 001,India.
∗e-mail:s −j −singh@yahoo.com
∗∗e-mail:s −b −rani@redi ffmail.com

Abstract: The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads.The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is di fferent  from its permeability in the horizontal direction.An analytical solution of the governing equations is obtained by taking the displacements and the pore pressure as the  basic state variables and using a combination of the Laplace and Hankel transforms.The problem of an axisymmetric nor-  mal load is discussed in detail.An explicit analytical solution is obtained for normal disc loading.Detailed  numerical computations reveal that the anisotropy in permeability as well as the com-pressibilities of the fluid and solid constituents of the poroelastic medium have signi ficant e ffects on the consolidation of the half-space.The anisotropy in permeability may accelerate the consoli- dation process and may lead to a dilution in the theoretical prediction of the Mandel –Cryer e ffect. The compressibility of the solid constituents may also accelerate the consolidation process.


Trachyhystrichosphaera Trachyhystrichosphaera Trachyhystrichosphaera:Anage-markeracanthomorph from the Bhander group, upper Vindhyan, Rajasthan
Purnima Srivastava
Centre of Advanced Study in Geology,Lucknow University,Lucknow 226 020,India.
e-mail:purnimasrivastava − 51@redi ffmail.com

Abstract: A highly diversi fied,advanced and exceptionally well preserved microfossil assemblage, dominated by a planktic community,has been recorded from petrographic thin sections of chert belonging to the Sirbu Shale Formation,Bhander group,upper Vindhyans,Rajasthan.Recently, it was noticed that the assemblage also contains well preserved,large-sized acanthomorphic acritarchs,Trachyhystrichosphaera considered to be an age-marker microfossil of the Cryogenian (850 –630 Ma).It is reported for the first time from any Indian microfossil assemblage of Proterozoic succession.The other microfossils of the Sirbu Shale Formation are:well preserved simple,small and large-sized sphaeromorphs;complex acanthomorphs,cyanobacterial community;especially a very small-sized but exceptionally well preserved Obruchevella,a form resembling Vol vox colonies; cf.vase-shaped microfossils and morphologies,possibly inclining towards fungal a ffinity,or lichen- like symbiotic associations of algae and fungi.Till date,Trachyhystrichosphaera has so far not been reported from successions older than the Tonian (1000 –850 Ma).It is believed that acantho- morphs attained maximum size in Ediacaran (630 –542 Ma),and further decreased in size in the Cambrian.The global paleontological literature indicates that Trachyhystrichosphaera ranges in age from Tonian –Ediacaran (1000 –542 Ma). The present record of Trachyhystrichosphaera as well as the earlier studies of micro and mega- scopic life of the Bhander Group in general and the Sirbu Shale in particular (aided by the absence of any  Cambrian fossil record)indicate that in all possibilities,age of the Sirbu Shale should lie near Cryogenian (850 –630 Ma)and the uppermost Bhander group,may incline towards the Ediacaran (630 –542 Ma).


Application of Markov chain and entropy analysis to lithologic succession –an example from the early Permian Barakar Formation,Bellampalli coal field, Andhra Pradesh,India
Ram Chandra Tewari 1 , ∗,DPSingh 2 , ∗∗and Z A Khan 3 , †
1 Department of Geology,Sri J.N.P.G.College,Lucknow 226 001,India.
2 SMEC India Pvt.Ltd.,5 th Floor,Tower C,DLF Building 8,Cyber City,Phase II,
Gurgaon 122 002,Haryana,India.
3 Directorate of Geology &Mining,Khanij Bhawan,Lucknow 226 001,India.
∗e-mail:ram −tewari@yahoo.com
∗∗e-mail:dp.singh@smecindia.com
†e-mail:zahid26aug@yahoo.co.in

Abstract: A statistical approach by a modi fied Markov process model and entropy function is used to prove that the early Permian Barakar Formation of the Bellampalli coal field developed distinct cyclicities during deposition.From results,the transition path of lithological states typical for the Bellampalli basin is as:coarse to medium-grained sandstone →interbedded fine-grained sandstone/shale →shale →coal and again shale.The majority of cycles are symmetrical but asymmetrical cycles are present as well.The chi-square stationarity test implies that these cycles are stationary in space and time.The cycles are interpreted in terms of in-channel,point bar and overbank facies association in a fluvial system.The randomness in the occurrence of facies within a cycle is evaluated in terms of entropy,which can be calculated from the Markov matrices.Two types of entropies are calculated for every facies state;entropy after deposition E (post)and entropy before deposition E (pre),which together form entropy set;the entropy for the whole system is also calculated.These values are plotted and compared with Hattori ’s idealized plots,which indicate that the sequence is essentially  a symmetrical cycle (type-B of Hattroi). The symmetrical cyclical deposition of early Permian Barakar Formation is explained by the lateral migration of stream channels in response to varying discharge and rate of deposition across the alluvial plain.In addition,the fining upward cycles in the upper part enclosing thick beds of  fine clastics,as well as coal may represent di fferential subsidence of depositional basin.



Eco-restoration of a high-sulphur coal mine overburden dumping site in northeast India: A case study
J Dowarah 1 , H P Deka Boruah 1, ∗,JGogoi 1 , N Pathak 1 , N Saikia 1 and A K Handique 2
1 Biotechnology Division, North-East Institute of Science & Technology, CSIR, Jorhat 785 006, Assam, India.
2 Biotechnology Department, Gauhati University, Guwahati 781 014, Assam, India.
∗e-mail: dekaboruah@yahoo.com hpdekaboruah@yahoo.com

Abstract: Eco-restoration of mine overburden (OB)or abandoned mine sites is a major environmental concern.In the present investigation,an integrated approach was used to rejuvenate a high-sulphur mine OB dumping site in the Tirap Collieries,Assam,India,which is situated in the Indo-Burma mega-biodiversity hotspot.A mine OB is devoid of true soil character with poor macro and micro- nutrient content and contains elevated concentrations of trace and heavy metals.Planting of herbs, shrubs,cover crops and tree species at close proximity leads to primary and secondary sere state succession within a period of 3 to 5 years.A variety of plant species were screened for potential use in restoration:herbs,including Sccharum spontaneum Cymbopogon winterianus Jowitt (citronella), and Cymbopogon flexuosus (lemon grass)cover plants,including Mimosa strigillosa M. striata and M. pigra shrubs,including Sesbania rostrata (dhaincha)and Cassia streata (cassia);and tree species,including Gmelina arborea (gomari)and Dalbergia sissoo (sissoo).Amendment with unmined soil and bio-organic matter was required for primary establishment of some plant species. Management of these plant species at the site will ensure long term sustainable eco-restoration of the coal mine-degraded land.


High-resolution satellite image segmentation using H¨ older exponents
Debasish Chakraborty 1 ∗, Gautam Kumar Sen 2 ∗∗and Sugata Hazra 2 †
1 Regional Remote Sensing Service Centre, Indian Space Research Organization, IIT Campus,
Kharagpur 721 302, India.
2 School of Oceanographic Studies, Jadavpur University, Kolkata 700 032, India.
∗e-mail: deba.isro@gmail.com deba1964@yahoo.com
∗∗e-mail: gksju@yahoo.co.in
†e-mail: shazra@geology.jdvu.ac.in

Abstract: Texture in high-resolution satellite images requires substantial amendment in the conventional seg- mentation algorithms.A measure is proposed to compute the H ¨older exponent (HE)to assess the roughness or smoothness around each pixel of the image.The localized singularity information is incorporated in computing the HE.An optimum window size is evaluated so that HE reacts to localized singularity.A two-step iterative procedure for clustering the transformed HE image is adapted to identify the range of HE,densely occupied in the kernel and to partition H ¨older expo- nents into a cluster that matches with the range.H ¨older exponent values (noise or not associated with the other cluster)are clubbed to a nearest possible cluster using the local maximum likelihood analysis.