Space-time variation and regionalization of seasonal and monthly summer monsoon rainfall of the sub-Himalayan region and Gangetic plains of India

The present study analyses space-time variation of the seasonal and monthly monsoon rainfall of the sub-Himalayan region and Gangetic plains of India by using rainfall data of 90 well-distributed stations for a period of 114 yr (1871 to 1984). Principal components (PCs) and varimaxrotated principal components (RPCs) are computed from the interstation similarity matrix. The 4 leading PCs explaining 52 to 61 of the variance respectively for seasonal and monthly rainfall are found to be statistically significant. When rotated by the varimax method these 4 PCs provide 4 distinct areas of homogeneous rainfall variability for both time scales. The most coherent region is located along the central longitude of the study area, with another coherent region over the extreme western parts. The area east of 81° E is divided into 2 coherent zones roughly along the 22° N parallel. It is noted that the regions thus identified will be useful in understanding climate variability and in weather prediction research

Seasonal variations of the relationship between some ENSO parameters and Indian rainfall

Canonical correlation analysis is used to examine the seasonal relationship between ENSO and Indian rainfall by analysing their 12 monthly values for an 80-year period. Three ENSO indices are considered. These ENSO indices are the Darwin surface pressure, the sea-surface temperature of the central and eastern equatorial Pacific, and rainfall of central equatorial Pacific islands (hereafter denoted as DSP, SST, and RAIN respectively). The ENSO indices are also analysed for relationships between themselves. The analysis reveals that the seasonal variations of these ENSO indices are highly intercoupled with no lag. These indices show the minimum association during April and the maximum after the monsoon season. Further, the seasonal variation of the Indian rainfall is found to be better associated with the seasonal variations of SST as compared with that of DSP or RAIN. This association is at its strongest during the period August-October. An apparent reversal in the relationship between ENSO and Indian rainfall is also observed from summer to winter. The warm ENSO years are associated with weak summer monsoon rainfall and at the same time high winter monsoon rainfall

A case for adaptive sub-carrier level power allocation in OFDMA networks

In today's OFDMA networks, the transmission power is typically fixed and the same for all the sub-carriers that compose a channel. The sub-carriers though, experience different degrees of fading and thus, the received power is different for different sub-carriers; while some frequencies experience deep fades, others are relatively unaffected. In this paper, we make a case of redistributing the power across the sub-carriers (subject to a fixed power budget constraint) to better cope with this frequency selectivity. Specifically, we design a joint power and rate adaptation scheme (called JPRA for short) wherein power redistribution is combined with sub-carrier level rate adaptation to yield significant throughput benefits. We further consider two variants of JPRA: (a) JPRA-CR where, the power is redistributed across sub-carriers so as to support a maximum common rate (CR) across sub-carriers and (b) JPRA-MT where, the goal is to redistribute power such that the transmission time of a packet is minimized. While the first variant decreases transceiver complexity and is simpler, the second is geared towards achieving the maximum throughput possible. We implement both variants of JPRA on our WARP radio testbed. Our extensive experiments demonstrate that our scheme provides a 35% improvement in total network throughput in testbed experiments compared to FARA, a scheme where only sub-carrier level rate adaptation is used. We also perform simulations to demonstrate the efficacy of JPRA in larger scale networks. © 2012 ACM

Association of the Indian summer monsoon with the northern hemisphere mid-latitude circulation

The association between the mid-latitude circulation and rainfall over the Indian region on an intraseasonal time-scale is investigated by considering 11 years (1974-1984) of Northern Hemisphere 500 hPa geopotential heights and rainfall data for the Indian summer monsoon months June through to September. On the basis of extensive correlation analysis between the geopotential heights and rainfall, it is seen that three regions over the mid-latitudes, the Manchurian region, the Algerian region and the Caspian sea region show positive correlation with rainfall over India, with higher values north of 20°N latitude. Lead and lag correlations between the heights at the locations identified above and rainfall over India reveals that some common element of low-frequency variability is influencing the mid-latitude circulation and Indian rainfall. On the interannual scale the connections between the winter-time low-frequency patterns (the Pacific/North Atlantic, the West Pacific Oscillation, the North Atlantic Oscillation and the Eurasian) and Indian summer monsoon rainfall (ISMR) are investigated. Only the West Pacific Oscillation pattern shows a significant relationship with the ISMR. Further, the interannual and the decadal variability is examined by using the Northern Hemisphere zonal index data for the period 1900-1993. Results reveal that the decadal-scale variability of the ISMR and the circulation features of the Northern Hemisphere are connected

Synoptic climatology of the daily 700 - mb summer monsoon flow pattern over India

The daily (mean of 0000 and 1200 GMT) 700 mb contour patterns over India are classified in five broad types for each summer monsoon month by using a chart-to-chart correlation method. Certain characteristics of these patterns, such as mutual transitions, persistence, preferred periods of occurrence and interrelationships are studied. Statistical probabilities of two threshold 24 h rainfall amounts (2.5 and 10 mm) being equated or exceeded for each type are computed for 107 stations, more or less uniformly distributed over India. This knowledge of the spatial distribution of precipitation probabilities associated with various circulation types can be used in forecasting probabilities of precipitation over the country if the circulation patterns can he forecast by numerical methods. These probabilities are then compared to the climatological and conditional probabilities of obtaining threshold rainfall amounts on different days of the subsequent 5-day period—given that the threshold rainfall occurred on the current day. The results, if averaged for all types and months, show that persistence is superior to the synoptic climatology developed in this study for forecasting precipitation probability for the next day over an regions and for forecasting precipitation probability up to 2–4 days—depending on region and threshold rainfall criteria. Synoptic climatology is superior to persistence as an aid for forecasting precipitation probability after 4 days over all the regions. Some shortcomings of the present study and future plans are described briefly

An operational medium range local weather forecasting system developed in India

A forecasting system for objective medium range location specific forecasts of surface weather elements was evolved at the National Centre for Medium Range Weather Forecasting (NCMRWF). The basic information used for this is the output from a general circulation model (GCM). The two essential components of the system are statistical interpretation (SI) forecast and direct model output (DMO) forecast. These are explained in brief. The SI forecast is obtained by using dynamical-statistical methods like model output statistics (MOS) and the perfect prog method (PPM) in which prediction of upper air circulation from a GCM around the location of interest is used. The DMO forecast is obtained from the prediction of surface weather elements from the GCM. The procedure for preparation of final forecast by using these two components and prevailing synoptic conditions is also explained. This is essentially a man-machine-mix approach. Finally, an evaluation of the forecast skill for the 1996 monsoon and some of the future plans are presented. Copyrigh

Evaluation of the CERES-Rice version 3.0 model for the climate conditions of the state of Kerala, India

The CERES-Rice version 3.0 crop growth simulation model was calibrated and evaluated for the agroclimatic conditions of the state of Kerala in India. Genetic coefficients were developed for the rice crop variety Jaya and used for the model evaluation studies. In four experiments using different transplanting dates during the virippu season (June to September) under rainfed conditions (i.e. no irrigation), the flowering date was predicted within an error of four days and date of crop maturity within an error of two days. The model was found to predict the phenological events of the crop fairly well. The grain yield predicted by the model was within an error of 3 for all the transplanting dates, but the straw yield prediction was within an error of 27. The high accuracy of the grain yield prediction showed the ability of the model to simulate the growth of the crop in the agroclimatic conditions of Kerala. It can be concluded from this study that the model can be used for making various strategic and tactical decisions related to agricultural planning in the state

Short Communication: A qualitative assessment of food security in an internally displaced persons camp in Kenya

The 2007/08 post-election violence in Kenya resulted in the displacement of an estimated 600 000 people. Current published research suggests that many of these internally displaced persons (IDPs) continue to have issues accessing basic needs, including food and water, impacting morbidity and mortality. This study aimed to assess food security and access to cooking fuel and water within an internally displaced persons’ (IDP) camp in Kenya. It was designed as a descriptive, qualitative study involving semi-structured interviews with members of households residing in the IDP camp. Participants were recruited through respondent-driven sampling using a network of coupons. Semi-structured interviews were utilised to determine key issues associated with the attainment of food security, access to cooking fuel and water among resident IDPs, targeting male household heads. Interview structure was based on framework for assessment of food security provided by the International Federation of the Red Cross. Recorded interviews then underwent thematic analysis using NVivo 10 (QSR International, Melbourne, Victoria). A total of 15 semi-structured interviews were completed with men at the camp, aged between 18 and 53. Thematic analysis shows that key elicited concerns regarding food security included lack of capital for agriculture, lack of dietary diversity, seasonal insecurity and anxiety about the future. Access to water was limited to a single borehole located within the camp. Few reliable and safe sources could be identified for cooking fuel. Thus, internally displaced persons residing at this camp continue to experience significant food insecurity. Despite being allocated land for agriculture, they lack capital for investment in agriculture and access to local food markets. Access to water and cooking fuel is limited and a source of significant concern. Initiatives to improve food security delivered through government and non-government programs are necessary to minimise the significant impact of such food insecurity on mental health and disease profiles as reported in other IDP settings.Key words: Internally displaced persons, Kenya, Food security, Qualitative study, Nutritio

Impact of Lifestyle Intervention for Management of the Modern Life Scourge of Polycystic Ovarian Syndrome among Girls – A Case Series

Polycystic ovarian syndrome (PCOS) is a complex endocrine, metabolic and reproductive disorder. It affects various body organs. Oligomenorrhea, hirsutism, insulin resistance, obesity and polycystic ovaries are its hallmark features. Usual medicines for PCOS focus on blood glucose and hormonal regulation. Diet, exercise and lifestyle changes for losing weight provide relief from symptoms. We describe here eight PCOS cases enrolled in an RCT. The study aimed to ascertain the impact of the lifestyle intervention for management of polycystic ovarian syndrome among girls. Anthropometric assessments and biochemical parameters, including reproductive hormones and insulin resistance, were performed at baseline and after 6 months of intervention, change in their health profile was noted. After intervention, menstrual regularity was achieved in all cases. The average weight loss was 4.07 kg (range 2.5–14 kg). The average BMI reduced from 26.6 to 25.0 and waist circumference from 94.1 to 86.6. At the end of the intervention, five cases had normal ovarian size, LH:FSH was normal in three cases. Out of six with insulin resistance, only one tested positive after intervention. One of the subjects said “I am very satisfied with the treatment. Almost all of my problems have been resolved – periods are regular, lab reports are normal, mood has improved, weight has reduced; other people ask me how I have lost weight.” Simple changes in lifestyle can easily provide relief in PCOS cases without any medical intervention