bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relation between southern oscillation index and Indian northeast monsoon as revealed in antecedent and concurrent modes
Authors: RAJ Y. E. A. , GEETHA B. 
Published: November 2021

The relation between Southern Oscillation Index (SOI) and Indian northeast monsoon has been studied in antecedent and concurrent modes based on monthly /seasonal mean SOI and monthly/seasonal rainfall data of Tamil Nadu for the 104 year period, 1901 to 2004. It has been found that a good negative relationship exists between the SOI and Indian northeast monsoon in antecedent and concurrent modes, the former being stronger than the later. In the concurrent mode, a strong negative relationship exists during the beginning of the season which changes as the season advances and turns positive during the fag end of the season. Such a changing nature of relationship is explained through the variation of latitudinal positions of 200 hPa Sub Tropical Ridge (STR) / Equatorial Trough (ET) and the location of these with reference to the latitudinal location of the area benefited by the northeast monsoon. It has been shown that a positive (negative) SOI shifts the STR north(south)wards throughout the year. The relationship between latitudinal position of STR and the Indian northeast monsoon rainfall (NMR) is negative during the beginning of the season and turns positive during the fag end of the season, which is similar to the relationship between SOI and NMR. The relation between upper tropospheric wind/temperature anomalies and NMR also shows a similar change in relationship. Westerly wind and negative temperature anomalies in October changing to easterly wind and positive temperature anomalies in January are by and large associated with good northeast monsoon activity. The reversal in the relationship between latitudinal position of STR and NMR as the season advances has also been partly explained based on theoretical considerations by invoking the tilting term of the vorticity equation. Thus the SOI appears to manifest itself on Indian northeast monsoon rainfall by way of modulating the latitudinal positions of STR. An analysis based on Australian “Rainman” software on winter monsoon rainfall of some Sri Lankan and southeast Asian stations has substantiated the changing nature of relationship. A study of dates of onset and withdrawal of Indian northeast monsoon in relation to SOI has revealed that negative (positive) SOI in September is associated with early (late) onset. But, continuation of negative SOI throughout the season favours early and abrupt withdrawal. Positive SOI during the fag end of the season is frequently associated with extension of the monsoon into January of the next year.
Climatological studies of lapse rates during summer months vis-à-vis All India Summer Monsoon Rainfall
Authors: JOSHI U. R. , RAO G. S. PRAKASA , KUMAR SHRAVAN 
Published: November 2021

The combined mean normal lapse rates for 0000 and 1200 UTC for 35 Radiosonde (RS) stations based on the period 1971-99 during the summer months (March to May) were worked out for standard levels and analysed. To know whether any relationship exists between the distribution of summer lapse rates and the all India summer monsoon rainfall (June to September), the mean lapse rates for three good monsoon years and six deficient years during the same period were worked out separately and the Lapse Rate Anomalies (LRAs) were examined in detail. In excessive monsoon rainfall years the LRAs were generally negative (instable atmosphere) during summer months (March-May) in the lower and middle troposphere and the anomalies were positive in the upper troposphere. In the deficient monsoon years, the case is reverse i.e., LRAs were positive in the lower troposphere (inhibiting the convective activity) while they were negative in the middle and upper troposphere. The same results were noticed in the recent worst monsoon year 2002 and bad monsoon year 2004.

The LRAs thus give signals in the months of March to May regarding the ensuing monsoon rainfall qualitatively and can be used as one of the tools for long range forecasting.
Relationship between Indian Ocean dipole mode and summer monsoon
Authors: BALA INDU , SINGH O. P. 
Published: November 2021

Utilizing the Indian Ocean Dipole Mode (IODM) and Indian Summer Monsoon Rainfall (ISMR) data for the period 1960-2002 the relationships between the IODM and monsoon onset over Kerala and rainfall distribution over the country have been studied. It has been found that stronger/weaker western pole during April-May is associated with delayed/early monsoon onset over Kerala. Stronger eastern pole during March-April seems to be associated with enhanced seasonal (June-September) rainfall over peninsular India. The IODM index of July-August can provide good indications of summer monsoon activity over peninsular India during the withdrawal phase of the monsoon, i.e., during September.
Morphometric analysis of Rasyan valley basin - A case study in the Republic of Yemen, using Remote Sensing and GIS techniques
Authors: MULIKI MOHAMMED MANSOOR AL , BASAVARAJAPPA H. T. 
Published: November 2021

Remote Sensing and GIS has given more importance for investigation of the geomorphological features based on the morphometric analysis duo to the diversity of data information by using digital map characters which help in moderating of data base information to get a different data like distance, area, point, line, polygon and qualitative data. This has decreased the errors which resulted by manual map sources. The main aim of this paper is the study of a morphometric analysis and characteristics of river basin area, basin shape, length, width and the ratio of length to the width, the ratio of rotation and circularity of the basin. It is also a study of relief characteristic, like slope and basin texture hypsometric curve. And also a study of drainage network characteristic like streams, stream order, length, drainage density, turn ratio, bifurcation ratio, weighted bifurcation ratio, type of drainage, and the relationship between all variables that mentioned above with rock types and structural movements of internal and external factors which are represented by relief, climate, soil, type of vegetation along with the human impact on the other hand. Results have been discussed for Rasyan valley basin in the Republic of Yemen using Landsat data.
Recent variations and trends in pan evaporation over India
Authors: VERMA I.  J. , JADHAV V. N. 
Published: November 2021

Thirty years pan evaporation time series data (1971-2000) recorded from US class-A evaporation pans for twenty well distributed locations in India, have been utilized in the present study. For all the locations, basic statistical parameters of annual evaporation [minimum, maximum, range, mean, standard deviation (S.D.) and coefficient of variation (C.V.)] have been computed. Annual, seasonal and monthly trends have been studied using linear trend analysis technique. Suitable graphs have been plotted to study the variations and changes in pan evaporation trends and to identify the specific periods as and when significant changes occur.

The mean annual pan evaporation was found to be lowest (1107 mm) at Buralikson and highest (3004 mm) at Rajkot. The highest C.V. of nearly 11% was observed at Rajamundry, Jodhpur, Buralikson and Nellore. The lowest C.V. of nearly 2% was observed at Ambikapur. Out of twenty locations, significant decreasing trend in annual pan evaporation was observed at fifteen locations and no significant trend at five locations. The annual dE/dt values varied from -6.27 (Canning) to -29.30 (Jodhpur) mm/year. The average annual dE/dt over India was found to be -14.90 mm/year. Linear relationship was obtained to quantitatively estimate annual dE/dt, at a given location, using pan evaporation range. On an average, over India, the contribution of seasonal dE/dt towards annual dE/dt (mm/year) is highest -5.63 (37.8 %) in Season-2 (March-April-May) and lowest -2.07 (13.9 %) in Season-1(January- February). On an average, over India, the contribution of monthly dE/dt towards annual dE/dt (mm/year) is highest - 2.08 (14.0 %) in May and lowest -0.77 (5.2 %) in August. Non linear relationships were obtained (a) to quantitatively estimate the average monthly dE/dt values over India, in any particular month (b) to quantitatively estimate the average cumulative dE/dt values over India (mm/year) upto any particular month and (c) to quantitatively estimate the contribution (per cent) towards average annual dE/dt over India, upto any particular month.
Incomplete Gamma distribution of rainfall for sustainable crop production strategies at Palampur, Himachal Pradesh
Authors: SINGH P. K. , RATHORE L. S. , SINGH K. K. , BAXLA A. K. , ATHIYAMAN B. 
Published: November 2021

The knowledge of rainfall pattern (amount and probability) helps in planning of crops to be grown in a region. Therefore weekly, monthly, seasonal and annual rainfall data for 33 years (1974-2006) for the station Palampur have been collected and its analysis has been attempted. The annual and monthly rainfall data were analyzed for finding out drought normality and abnormality. The analysis indicated that the rainfall is mainly confined in annual rainfall 2343 mm with 25.7 per cent variability. The standard deviation of annual rainfall is 62.8 mm. Each standard week from 26th to 35th receive a rainfall of more than 100 mm, indicating the crop period. Seed sowing in paddy nursery in the Palampur region generally takes places immediately after initiation of monsoon during 23rd - 25th standard meteorological weeks and transplanting is carried out around 27th or 28th standard meteorological week. The tillering, 50 percent flowering and dough stage are observed during 32-33rd, 37-38th and 40-41st standard meteorological weeks respectively.
Evaluation of bias free rainfall forecasts and Kalman filtered temperature forecasts of T-80 model over Indian monsoon region
Authors: BHARDWAJ RASHMI , KUMAR ASHOK , MAINI PARVINDER 
Published: November 2021

A forecasting system for obtaining objective medium range location specific forecast of surface weather elements is evolved at National Centre for Medium Range Weather Forecasting (NCMRWF). The basic information used for this is the output from the general circulation models (GCMs) T-80/T-254 operational at NCMRWF. The most essential component of the system is Direct Model Output (DMO) forecast. This is explained in brief. Direct Model Output (DMO) forecast is obtained from the predicted surface weather elements from the GCM. The two important weather parameters considered in detail are rainfall and temperature. Both the weather parameters have biases. While the bias from the rainfall is reduced by adopting bias removal technique based upon threshold values for rainfall and for removing bias from temperature forecast a two parameter Kalman filter is applied. The techniques used for getting bias free forecast are explained in detail. Finally an evaluation of the forecast skill for the Kalman filtered temperature forecast and bias free rainfall forecast during monsoon 2007 is presented.
Influence of actual evapotranspiration, growing degree days and bright sunshine hours on yield of finger millet
Authors: PATIL C. S. , PUTTANNA B. 
Published: November 2021

Based on the result of an experiment conducted for three years from 1997-1999 during Kharif, under rainfed conditions, a model has been generated for relating crop coefficient of ragi with time at Bangalore. The peak value of crop coefficient was found to be 1.02 on 66th day after sowing. The multiple regression equation was also generated based on the accumulated values of actual evapotranspiration (AET), growing degree days (GDD) and bright hours of Sunshine (BHS) from sowing to physiological maturity, using the field experimental data for the period 1998-2005. This multiple regression equation can be applied to forecast the yield of finger millet under rainfed conditions. This model was validated for the crop grown during Kharif 2005.
Role and impact of Siberian High on the temporal variation of Indian northeast monsoon rainfall
Authors: GEETHA B. , RAJ Y. E. A. 
Published: November 2021

The relation between the intensity of Siberian High, defined as the mean sea level pressure over the Siberian region bounded by 87.5 & 102.5° E longitudes and 47.5 & 52.5° N latitudes (PSH) and Indian northeast monsoon rainfall has been studied in antecedent and concurrent modes based on monthly/seasonal mean PSH and monthly/seasonal rainfall data of Tamil Nadu (NMR) for the 34 year period, 1971 to 2004. It has been found that a positive relationship exists between the PSH and NMR of October-November (ON) which is significant in the antecedent mode [PSH(AS/Sep)] and modest in concurrent mode. The relationship turns negative for NMR (Dec) with both PSH(Sep) (antecedent) and PSH(Dec) (concurrent). By and large, negative anomaly profile of PSH during September-November (SON) followed by a positive PSH (Dec) anomaly is associated with a deficient NMR, but, a normal to positive PSH anomaly profile in SON becoming negative in December is associated with an excess NMR. The manifestation of PSH on NMR has been shown to be by way of modulating the strength of low level easterlies over the Bay of Bengal off the southeast coast of peninsular India as well as the latitudinal positions of Sub Tropical Ridge at 200 hPa (STR) and Equatorial Trough at 850 hPa (ET) over India. An intense PSH (Sep) is associated with strengthening of easterlies over the Bay of Bengal as well as southward location of STR/ET thereby favouring a good NMR (ON). During December, a weaker than normal PSH (Dec) is associated with northward location of ET from its normal latitudinal position near the equator which becomes conducive for good NMR(Dec). That a weaker than normal PSH in December is associated with good NMR(Dec) is comprehended from an analysis of time series of PSH. It has been found that the PSH itself undergoes a phase change in December on most occasions, i.e., an intense PSH (Nov) is by and large, followed by a weaker than normal PSH (Dec) and vice versa.
Simulation modeling of rice genotypes of yield and yield attributes at different nitrogen levels and different dates of transplanting using CERES 3.5 v for eastern Uttar Pradesh
Authors: KUMAR NEERAJ , TRIPATHI P. 
Published: November 2021

The present investigation was carried out at Agrometeorological Instructional Farm of Narendra Deva University of Agriculture & Technology, Kumarganj, Faizabad (U.P.) during Kharif season of 2005-06 to investigate the CERES v 3.5 model validations for rice at different dates of transplanting and different genotypes. Treatment consisted of three genotypes, viz., Sarjoo-52, NDR-359 and Pant Dhan-4, two dates of transplanting, viz., July 5, 2005 and July 25, 2005 & three nitrogen levels, viz., 80 kg/ha, 120 kg/ha and 160 kg/ha. The experiment was laid out in Randomized Block Design (RBD). From the response of simulation model it is observed that accuracy of simulated value decrease with late sowing in all the genotypes. Among the varieties the Pant Dhan-4 was found to have maximum closeness to observed value followed by Sarjoo-52 and NDR-359 at all nitrogen level for Biomass (gm/m2). Grain yield predication at 120 kg N level was found closest in Pant Dhan-4 and Sarjoo-52, while in NDR­-359 shows the better closeness at 160 kg N in both dates of transplanting. In the weight/grain (gm) 120 kg nitrogen level was found to have highest accuracy of (100%), i.e., no difference between observed and predicted value in both transplanting dates and nitrogen level.
Technical feasibility on reception of VHRR signals from Kalpana-1 satellite in the event of contingency with the existing operational ground receiving system
Authors: YADAV J. K. S. , CHAKARBORTY A. K. , GIRI R. K. 
Published: November 2021

National Satellite Meteorological Center (NSMC), of India Meteorological Department is performing the vital role of receiving signals of meteorological data transmitted by KALPANA-1/INSAT series of national satellites and processing the data to generate various meteorological products for monitoring meteorological, environmental and climatological conditions. The satellite signals are currently being received through a 7.5 m diameter parabolic dish antenna installed at INSAT Earth Station of IMD located at Mausam Bhawan Complex, New Delhi.
In this study an attempt has been made to receive and process the VHRR signals of KALPANA-1 through a smaller (3.8m) diameter parabolic dish antenna available at earth station .The link calculations have been made to show extra 2 db margin what is theoretically required and it will be sufficient for image capturing. We had also compared the result with existing 7.5m diameter antenna and observe that quality of satellite pictures received with 3.8m diameter antenna are also equally good.
The purpose of this study is to keep in operational readiness a backup antenna for the reception of KALPANA-1 in the event of any unforseen contingency with the existing 7.5m diameter parabolic dish antenna, using the existing infrastructure of IMD.
Unprecedented rainfall over Bangalore city during October, 2005
Authors: MOHAPATRA M. , KUMAR NARESH , BANDYOPADHYAY B. K. 
Published: November 2021

The Central Observatory of India Meteorological Department (IMD) at Palace Road, Bangalore reported a record highest monthly rainfall of 604 mm during October, 2005. It was the highest ever monthly rainfall recorded over Bangalore city. However, the surrounding stations in Bangalore district recorded less rainfall. To find out the physical processes leading to this rainfall, the characteristics of rainfall over different stations in Bangalore urban and rural districts during October, 2005 and associated synoptic and thermodynamic features during the month are analysed. The Urban Heat Island (UHI) effect and role of pollution parameters and their relationship with this rainfall have also been analysed. This study can be utilized in better understanding of the impact of urbanization and pollution on rainfall, especially heavy rainfall. It can also help in predicting the heavy rainfall events over the urban centres.
The study endorses the earlier finding that the UHI effect leads to moisture convergence and pollutants may work as hygroscopic nuclei over the region to enhance rainfall near the urban centre.
Recent winter warming over India – spatial and temporal characteristics of monthly maximum and minimum temperature trends for January to March
Authors: JASWAL A. K. 
Published: November 2021

In the backdrop of recent warmer winters over India, temperature series of 174 stations well distributed over the country were statistically analyzed to document the long term variations and trends in monthly mean maximum and minimum temperatures for January to March. From the trend analysis, February month has emerged as the warmer winter month over North India where increase in both maximum (+0.29° C / decade) and minimum (+0.38° C / decade) temperatures is highest with noteworthy increase in maximum temperature at a rate 1.5 times that of the South India averaged increase. Spatially, North India minimum temperature trends for February and March and South India maximum temperature trends for all months are more coherent.

Both day-time and night-time total cloud amounts are increasing significantly over Indo-Gangetic plains and south peninsula and decreasing significantly in central and east India. However increase in temperatures over extreme south peninsula in January and March is difficult to explain on the basis of increase in day-time total cloud amount indicating strong influence of other climatic factors. At the same time, sea surface temperatures of the Arabian Sea and the Bay of Bengal are rising and there is strong positive correlation between land surface temperatures and sea surface temperatures suggesting significant contribution of warmer sea waters which may have important climatic implications over neighbouring regions.
Study of rainfall departure over catchments of Bihar plains
Authors: JHA T. N. , RAM R. D. 
Published: November 2021

Station wise daily rainfall data of sixty years is used to study rainfall departure and variability in Kosi, Kamala/Bagmati/Adhwara and Gandak/Burhi Gandak catchments during monsoon season. Station and catchment wise rainfall time series have been made to compute rainfall departure and Coefficient of Variation (CV). Southern Oscillation Index (SOI), Multivariate ENSO Index (MEI) and ENSO strength based on percentile analysis are used to ascertain their impact on rainfall distribution in the category as excess, normal, deficient and scanty. Results indicate that the variability is greater over Kosi as compared to the other catchments. Probability of normal rainfall is found 0.75 and there is no possibility of scanty rain over the catchments during El Nino and La Nina year. Similarly probabilities of normal, deficient, excess rainfall are found as 0.67, 0.18 and 0.15 respectively during mixed year. SOI has emerged as principal parameter which modifies the departure during El Nino and La Nina year. MEI along with ENSO strength are more prominent during mixed year particularly to ascertain deficient and excess rain in weak and strong- moderate La Nina respectively .
Precipitable water vapour monitoring using ground based GPS system
Authors: PUVIARASAN N. , GIRI R. K. , RANALKAR MANISH 
Published: November 2021

The sensing of near real time Precipitable Water Vapour (PWV) using Global Positioning System (GPS) over Indian region were analyzed. GPS data collected from five stations at hourly interval were utilized to determine near real time PWV using GAMIT software. Sliding window technique was used to derive near real time PWV. The PWV determined from GPS observations of each site were compared with respective radiosonde measurements. The results shows that the derived GPS precipitable water well agree for some stations with the independent radiosonde measurements. We have also examined the variation of hourly GPS-PWV with hourly rainfall observation and found that PWV increases significantly before the event take place and decreases after the event.
Signatures of northeast monsoon activity and passage of tropical cyclones in the integrated precipitable water vapour estimated through GPS technique
Authors: BALACHANDRAN S. , GEETHA B. 
Published: November 2021

Water vapour represents a key variable in the atmospheric processes. The importance of assessing water vapour availability in the atmosphere is indicated by the currently prevalent use of vast number of observing systems, both of in-situ and remote sensing types, designed to measure its distribution accurately over wide ranges of space and time scales. One of the widely used techniques world over is use of ground based GPS receivers for measurement of total precipitable water vapour in the atmosphere over the station. One such system is being operated at Chennai since 2007. An analysis of hourly Integrated Precipitable Water Vapour (IWV) data received from this system during Northeast Monsoon (NEM) season of 2008 shows the signatures of NEM activity and the passage of tropical disturbances like cyclonic storms and depressions in the vicinity of the GPS observation site. The GPS based IWV values are found to agree fairly well with radiosonde based IWV values and a good correlation exists between them. The IWV values obtained from GPS based system are found to be consistent with activity of Northeast monsoon with increase (decrease) of IWV during active (weak) phase of NEM 2008. The general expected trend of increase in IWV with approach of tropical systems in the vicinity of GPS station, reaching maximum during closest approach and again its decrease with increase of distance from the station is noticed. The diurnal variation of GPS based IWV estimates during NEM 2008 does not appear to be significant.