Environmental Energetics aspects of anomalous Cyclogenesis over Indian Ocean during 2013

An attempt has been made to understand the dynamics behind anomalous cyclogenesis over Indian Ocean during 2013 cyclone seasons, from an atmospheric energetics point of view. Salient features of the results of this study are:Maximum intensification of all the intense cyclonic vortices was associated with an enhancement in both conversion from eddy available potential energy to eddy kinetic energy (AE to KE ) and zonal kinetic energy to eddy kinetic energy (KZ to KE).During intensification of the storms both AE and AZ have shown to be dissipated, suggesting the intensification of storms at the cost of AE and AZ . For all of these systems baroclinic eddy kinetic energy conversions [conversion from AE to KE ] dominates over barotropic eddy kinetic energy conversions [conversion from KZ to KE]. Anomalous cyclogenesis in 2013, at least partly may be attributed to a positive anomaly in Moist Static Energy (MSE) of the environment along with positive anomaly in baroclinic and barotropic eddy kinetic energy conversion during cyclone seasons over the region under study.Release of convective instability in the atmosphere may also be attributed, at least partly, for anomalous cyclogenesis in 2013

Mezoskalna objektivna analiza dnevne oborine pomoću satelitskih i konvencionalnih mjerenja nad područjem indijskog ljetnog monsuna

A mesoscale objective analysis scheme for producing daily rainfall analysis on a regular latitude/longitude grid over the Indian monsoon region is described. The Barnes scheme is applied to interpolate irregularly distributed daily rainfall data on to a regular grid. The spatial resolution of the interpolated arrays is 0.25 degrees of latitude by 0.25 degrees of longitude. Daily rainfall derived from INSAT IR radiances and raingauge observations are combined to produce this analysis. Some objectively determined constraints are employed in this study: (i) weights are determined as a function of data spacing, (ii) in order to achieve convergence of the analysed values three passes through the data are considered and there is automatic elimination of wavelengths smaller than twice the average data spacing. The case of a typical westward moving monsoon depression during the 1994 monsoon season is selected to represent the characteristics of the analysed rainfall. Objective analyses of six days (16 to 21 August 1994) have been carried out using Barnes three pass scheme. The weighting function scale length parameter (c, denominator in the exponential Gaussian weight function) is varied from over a range of values and the root mean square (rms) errors are computed to select the appropriate value of c. The value of c depends on the number of correction passes being performed and on the density of the observations. The characteristics of the output field from this analysis system have been examined by comparing the analysed rainfall with the observed values. The heavy rainfall over the Western Ghat of India has been clearly brought out in this analysis.Ovdje je opisana shema mezoskalne objektivne analize za dobivanje dnevne oborine u pravilnoj geografskoj mreži nad područjem monsuna u Indiji. Za nejednako raspoređene podatke o dnevnoj oborini primijenjena je Barnes-ova shema za interpolaciju u pravilnoj mreži. Prostorna rezolucija interpoliranih podataka vrši se svakih 0.25° geografske širine i 0.25° geografske dužine. Analiza je omogućila kombinirani uvid u dnevnu oborinu izvedenu na temelju satelitskih slika i mjerenja kišomjernih postaja. Ovdje se koriste neka objektivna ograničenja: (i) težine su određene kao funkcije udaljenosti podataka, (ii) radi postizanja konvergencije analiziranih vrijednosti koriste se tri filtra kroz podatke čime se postigla automatska eliminacija valnih duljina manjih od dvostruke srednje udaljenosti među podacima. Za predstavljanje karakteristika analizirane oborine, odabran je slučaj tipične monsunske depresije koja se kreće prema zapadu tijekom monsunske sezone godine 1994. Napravljene su objektivne analize od 6 dana (od 16. do 21. kolovoza 1994.) korištenjem Barnes-ove sheme. Pritom je mijenjana težinska funkcija parametra skale duljine (c, nazivnik u eksponencijalnoj Gauss-ovoj težinskoj funkciji) za čitav niz vrijednosti, te je računan korijen srednje kvadratne pogreške za određivanje odgovarajuće vrijednosti c-a. Vrijednost c ovisi o gustoći mjerenja te o broju korištenih korektivnih filtra. Ispitivale su se karakteristike analiziranog izlaznog polja pomoću usporedbe s analiziranom mjerenom oborinom. U ovoj su analizi jasno izvedene obilne oborine nad zapadnim Ghat-om u Indiji

The Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX): overview and preliminary results

While the demand for enhancing rainfall through cloud seeding is strong and persistent in the country, considerable uncertainty exists on the success of such an endeavour at a given location. To understand the pathways of aerosol-cloud interaction through which this might be achieved, a national experiment named Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) in two phases, was carried out. The rationale of CAIPEEX, the strategy for conducting the experiment, data quality and potential for path-breaking science are described in this article. Pending completion of quality control and calibration of the CAIPEEX phase-II data, here we present some initial results of CAIPEEX phase-I aimed at documenting the prevailing microphysical characteristics of aerosols and clouds and associated environmental conditions over different regions of the country and under different monsoon conditions with the help of an instrumented research aircraft. First-time simultaneous observations of aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) over the Ganges Valley during monsoon season show very high concentrations (> 1000 cm-3) of CCN at elevated layers. Observations of elevated layers with high aerosol concentration over the Gangetic valley extending up to 6 km and relatively less aerosol concentration in the boundary layer are also documented. We also present evidence of strong cloud- aerosol interaction in the moist environments with an increase in the cloud droplet effective radius. Our observations also show that pollution increases CDNC and the warm rain depth, and delays its initiation. The critical effective radius for warm rain initiation is found to be between 10 and 12 µm in the polluted clouds and it is between 12 and 14 µm in cleaner monsoon clouds

The cloud aerosol interaction and precipitation enhancement experiment (CAIPEEX): Overview and preliminary results

While the demand for enhancing rainfall through cloud seeding is strong and persistent in the country, considerable uncertainty exists on the success of such an endeavour at a given location. To understand the pathways of aerosol-cloud interaction through which this might be achieved, a national experiment named Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) in two phases, was carried out. The rationale of CAIPEEX, the strategy for conducting the experiment, data quality and potential for path-breaking science are described in this article. Pending completion of quality control and calibration of the CAIPEEX phase-II data, here we present some initial results of CAIPEEX phase-I aimed at documenting the prevailing microphysical characteristics of aerosols and clouds and associated environmental conditions over different regions of the country and under different monsoon conditions with the help of an instrumented research aircraft. First-time simultaneous observations of aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) over the Ganges Valley during monsoon season show very high concentrations (> 1000 cm-3) of CCN at elevated layers. Observations of elevated layers with high aerosol concentration over the Gangetic valley extending up to 6 km and relatively less aerosol concentration in the boundary layer are also documented. We also present evidence of strong cloud- aerosol interaction in the moist environments with an increase in the cloud droplet effective radius. Our observations also show that pollution increases CDNC and the warm rain depth, and delays its initiation. The critical effective radius for warm rain initiation is found to be between 10 and 12 μm in the polluted clouds and it is between 12 and 14 μm in cleaner monsoon clouds

Optimal nonlinear wind analysis over the Indian region by iterative correction scheme

156-167The development of satellite observing systems (asynoptic observations) has led to the idea that dynamical evolution of atmospheric flow should be explicitly taken into account while defining the initial conditions of the forecast. In view of this, objective analysis of wind field over the Indian region has been made by applying an iterative analysis correction scheme proposed by Lorenc [Lorenc A C, Q J R Meteorol Soc (UK) 112 (1986) 1177]. The most likely analysis of wind field for a given set of observations is obtained. In this process, at each iteration, the height values are estimated from wind field by nonlinear balance equation. Their partial derivatives with reference to wind field are used in modifying the weights and to obtain the convergence. The solution of the iteration is the most likely analysis of wind field. The scheme has been tested for two cases of monsoon depressions, 2-5 August 1988 and 28-30 July 1991. The analysis has been compared with the conventional liner optimum interpolation analysis. Divergence and vorticity computed from both the analysed wind fields have been examined. Synoptic features depicted in both the analyses are similar and agree with cloud pictures, suggesting that the scheme has performed well and also it is possible to introduce the information on approximate geostrophic balance in assimilation process

Oceansat-1 derived met-ocean parameters during various stages of monsoon depression of June 1999, along Orissa coastline, east coast of India

113-121After the launch of Oceansat-1 (IRS-P4) on May 26, 1999, weather scientists got the opportunity to study some of the meteorological and oceanographic (met-ocean) parameters associated with the weather systems formed over the oceanic regions around India, even under cloudy conditions. Oceansat-1 carries multifrequency scanning microwave radiometer (MSMR) which has a capability to provide information of certain parameters viz. sea surface wind speeds (SSW), sea surface temperature (SST), integrated water vapour (IWV) and cloud liquid water content (CLW). A monsoon depression was formed over the Bay of Bengal on 17 June 1999 causing widespread rainfall over Orissa coast and the adjoining regions. Oceansat-1 derived met-ocean parameters were studied during various stages of this depression. The maximum values of these parameters during the life cycle of the depression over the Bay of Bengal were SST : 30º - 31º C, SSW : 16-18 m/s, IWV : 7.0 g/cm², CLW : 90-100 mg/cm². It was observed that SSW, IWV and CLW show high values one to three days before the formation of the depression. High values, shape and steep gradients of the met-ocean parameters give prior indication of formation/intensification of the weather system and its probable location. SST reduced by about 1º-2º after the passage of the low pressure system over the region

Orissa super cyclone of October 1999 as revealed by IRS-P4 satellite data

35-42A super cyclone hit Orissa coast during 24-31 Oct. 1999 causing vast damage to property and life. Life cycle of this super cyclonic storm from its genesis to landfall is studied using IRS-P4 satellite derived parameters over the oceanic region. The parameters, viz. sea surface temperature, sea surface wind, integrated water vapour, cloud liquid water content are studied over the region 5-25° N and 70-100°E. Synoptic surface pressure charts were compared with INSAT imagery. The IRS-P4 satellite data supplemented the data from INSAT in studying various characteristics associated with the super cyclone

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Not AvailablePlant growth-promoting rhizobacteria (PGPR) have multifarious beneficial activities for plant growth promotion; act as source of metabolites, enzymes, nutrient mobilization, biological control of pests, induction of disease resistance vis-a-vis bioremediation potentials by phytoextraction and detoxification of heavy metals, pollutants and pesticides. Agrochemicals and synthetic pesticides are currently being utilized widely in all major field crops, thereby adversely affecting human and animal health, and posing serious threats to the environments. Beneficial microorganisms like PGPR could potentially substitute and supplement the toxic chemicals and pesticides with promising application in organic farming leading to sustainable agriculture practices and bioremediation of heavy metal contaminated sites. Among field crops limited bio-formulations have been prepared till now by utilization of PGPR strains having plant growth promotion, metabolites, enzymes, nutrient mobilization and biocontrol activities. The present review contributes comprehensive description of PGPR applications in field crops including commercial, oilseeds, leguminous and cereal crops to further extend the utilization of these potent groups of beneficial microorganisms so that even higher level of crop productivity and quality produce of field crops could be achieved. PGPR and bacteria based commercialized bio-formulations available worldwide for its application in the field crops have been compiled in this review which can be a substitute for the harmful synthetic chemicals. The current knowledge gap and potential target areas for future research have also been projected.Not Availabl