Monsoon Months Research Articles

Evidence for a gas-flaring source of alkanes leading to elevated ozone in air above West Africa

As part of the African Monsoon Multidisciplinary Analysis (AMMA) project, the FAAM BAe-146 research aircraft sampled the lower and mid-troposphere around the West Africa sub-region. Back trajectory analysis of the air parcels sampled on-board during the entire duration of the flights showed the history and fate of the air parcels. Data from flights B228 and B231 showed strongly enhanced carbon monoxide (CO) and ozone levels attributable to emissions of anthropogenic origin from the city of Lagos and gas flaring activities in the Nigeria oil fields. The elevated levels of ozone and CO observed at about 6 km above the sea-level on flight B231 were attributed to long-range transport of biomass burning plume from the East, around Sudan. The strongly enhanced mixing ratios of short-chained alkanes and CO (> 400 ppbv) observed from measurements on flights B228 and B231 are indicative of natural gas/combustion sources. Flight B222 sampled air parcels strongly impacted by emissions from Lagos but not from the Nigeria oil field and measured relatively lower mixing ratios of ozone, CO and short-chained alkanes species. Results from this study strongly suggests gas flaring emissions in the Niger Delta area to be a prominent contributor to the enhanced levels of short-chained alkane species observed in Lagos metropolis, especially during the West Africa Monsoon (WAM) months and, hence, a significant source of atmospheric aerosol in the sub-region. Key words: African Monsoon Multidisciplinary Analysis (AMMA), gas flaring, West Africa Monsoon, alkanes, ozone, Niger Delta.

Distributional changes in rainfall and river flow in Sarawak, Malaysia

Climate change may not change the rainfall mean, but the variability and extremes. Therefore, it is required to explore the possible distributional changes of rainfall characteristics over time. The objective of present study is to assess the distributional changes in annual and northeast monsoon rainfall (November-January) and river flow in Sarawak where small changes in rainfall or river flow variability/distribution may have severe implications on ecology and agriculture. A quantile regression-based approach was used to assess the changes of scale and location of empirical probability density function over the period 1980-2014 at 31 observational stations. The results indicate that diverse variation patterns exist at all stations for annual rainfall but mainly increasing quantile trend at the lowers, and higher quantiles for the month of January and December. The significant increase in annual rainfall is found mostly in the north and central-coastal region and monsoon month rainfalls in the interior and north of Sarawak. Trends in river flow data show that changes in rainfall distribution have affected higher quantiles of river flow in monsoon months at some of the basins and therefore more flooding. The study reveals that quantile trend can provide more information of rainfall change which may be useful for climate change mitigation and adaptation planning.

Latitudinal variation in summer monsoon rainfall over Western Ghat of India and its association with global sea surface temperatures

The Western Ghats (WG) of India are basically north-south oriented mountains having narrow zonal width with a steep rising western face. The summer monsoon winds during June to September passing over the Arabian Sea are obstructed by the WG and thus orographically uplift to produce moderate-to-heavy precipitation over the region. However, it is seen that characteristic features of rainfall distribution during the season vary from north to south. Also its correlation with all-India summer monsoon rainfall increases from south to north. In the present study, an attempt is also made to examine long-term as well as short-term trends and variability in summer monsoon rainfall over different subdivisions of WG using monthly rainfall data for the period 1871–2014. Konkan & Goa and Coastal Karnataka show increase in rainfall from 1871 to 2014 in all individual summer monsoon months. Short-term trend analysis based on 31-year sliding window indicates that the trends are not monotonous, but has epochal behavior. In recent epoch, magnitudes of negative trends are consistently decreasing and have changed its sign to positive during 1985–2014.It has been observed that Indian Ocean Dipole (IOD) plays a dominant positive role in rainfall over entire WG in all summer monsoon months, whereas role of Nino regions are asymmetric over WG rainfall. Indian summer monsoon is known for its negative relationship with Nino SST. Negative correlations are also seen for WG rainfall with Nino regions but only during onset and withdrawal phase. During peak monsoon months July and August subdivisions of WG mostly show positive correlation with Nino SST.

Impact of summer monsoon on the elevation‐dependence of meteorological variables in the south of central Himalaya

ABSTRACTThe South Asian summer monsoon brings abundant precipitation and associated latent heat release to the south of central Himalaya, and alters hydrothermal conditions of this region. This study explored the impact of South Asian summer monsoon on the elevation‐dependence of meteorological variables along the south slope of Mt. Everest in the central Himalaya, which is crucial to modelling the glacio‐hydrological processes in this elevated region. The data were collected at five stations deployed at 2660–5600 m above sea level (asl) along the slope during 2007–2011. Major findings are the following: (1) The amount of precipitation during the monsoon season usually decreases with elevation but it is relatively uniform between 3600 and 5000 m asl. This uniform profile may be attributed to the monsoon–terrain–land interactions, particularly to the retard effect of glacier cooling on daytime upvalley wind; (2) Cloud shielding effects cause lower solar radiation and higher downward longwave radiation in the monsoon than in the other seasons. In particular, higher elevations have more clouds in the afternoon, resulting in an abnormal elevation‐dependence of solar radiation (i.e. higher elevations receive less solar radiation); (3) Strong daytime upvalley wind and moist convection homogenizes the vertical distributions of air mass along the slope, causing a constant lapse rate of both surface air temperature and dew‐point temperature (representing humidity) during typical monsoon months, but this phenomenon is not found in the other seasons. These findings provide critical guidance for extrapolating the meteorological variables from lower to higher elevations in this region.

Prediction of Monthly Summer Monsoon Rainfall Using Global Climate Models Through Artificial Neural Network Technique

The monthly prediction of summer monsoon rainfall is very challenging because of its complex and chaotic nature. In this study, a non-linear technique known as Artificial Neural Network (ANN) has been employed on the outputs of Global Climate Models (GCMs) to bring out the vagaries inherent in monthly rainfall prediction. The GCMs that are considered in the study are from the International Research Institute (IRI) (2-tier CCM3v6) and the National Centre for Environmental Prediction (Coupled-CFSv2). The ANN technique is applied on different ensemble members of the individual GCMs to obtain monthly scale prediction over India as a whole and over its spatial grid points. In the present study, a double-cross-validation and simple randomization technique was used to avoid the over-fitting during training process of the ANN model. The performance of the ANN-predicted rainfall from GCMs is judged by analysing the absolute error, box plots, percentile and difference in linear error in probability space. Results suggest that there is significant improvement in prediction skill of these GCMs after applying the ANN technique. The performance analysis reveals that the ANN model is able to capture the year to year variations in monsoon months with fairly good accuracy in extreme years as well. ANN model is also able to simulate the correct signs of rainfall anomalies over different spatial points of the Indian domain .

A STUDY ON LONG TERM RAINFALL PATTERN OF DHUBRI AND GUWAHATI IN ASSAM, INDIA: A TIME SERIES APPROACH

Understanding the rainfall pattern is tough for the solution of several regional environmental issues of water resources management, with implications for agriculture, climate change, and natural calamity such as floods and droughts. Statistical computing, modelling and forecasting meteorological data are the key instruments for studying these patterns. This study aims to establish the rainfall trends of the two stations of Assam viz. Guwahati and Dhubri. The collected data is secondary in nature and obtained from the website of Global Precipitation Climatology Project (GPCP) of NASA, Goddard Space Flight Center, United States consisting of 36 years monthly rainfall records for the period 1979-2014. We have performed Sen’s slope method and Mann-Kendall test to assess the magnitude along with the statistical significance of trend. So far as monthly analysis is concerned, a gradual decrease in rainfall has been observed for maximum months in both the stations. Moreover, seasonal analysis has witnessed a noticeable similarity between the stations that is the presence of significant downward trend for winter and monsoon months over the entire period of 1979-2014.

Tree seed traits' response to monsoon climate and altitude in Indian subcontinent with particular reference to the Himalayas.

Seed traits are related to several ecological attributes of a plant species, including its distribution. While the storage physiology of desiccation‐sensitive seeds has drawn considerable attention, their ecology has remained sidelined, particularly how the strong seasonality of precipitation in monsoonal climate affects their temporal and spatial distribution. We compiled data on seed mass, seed desiccation behavior, seed shedding, and germination periodicity in relation to monsoon and altitude for 198 native tree species of Indian Himalayas and adjoining plains to find out (1) the adaptive significance of seed mass and seed desiccation behavior in relation to monsoon and (2) the pattern of change in seed mass in relation to altitude, habitat moisture, and succession. The tree species fall into three categories with respect to seed shedding and germination periodicities: (1) species in which both seed shedding and germination are synchronized with monsoon, referred to as monsoon‐synchronized (MS, 46 species); (2) species in which seed germination is synchronized with monsoon, but seeds are shed several months before monsoon, referred to as partially monsoon‐synchronized (PMS, 112 species); and (3) species in which both shedding and germination occur outside of monsoon months, referred to as monsoon‐desynchronized (MD, 39 species). The seed mass of MS species (1,718 mg/seed) was greater than that of PMS (627 mg/seed) and MD (1,144 mg/seed). Of the 40 species with desiccation‐sensitive seeds, 45% belong to the MS category, almost similar (approx. 47%) to woody plants with desiccation‐sensitive seeds in evergreen rain forests. Seed mass differed significantly as per seed desiccation behavior and successional stage. No relationship of seed mass was found with altitude alone and on the basis of seed desiccation behavior. However, seed mass trend along the altitude differed among monsoon synchronization strategies. Based on our findings, we conclude that in the predicted climate change (warming and uncertain precipitation pattern) scenario, a delay or prolonged break‐spell of monsoon may adversely affect the regeneration ecology of desiccation‐sensitive seed‐bearing species dominant over large forest areas of monsoonal climate.

Changes in Seasonality Index Over Sub-Divisions of India During 1951-2015

Background:The varied topographical features of the Indian region are responsible for variation in distribution of rainfall over different parts of the country. More than 80% of the country’s rainfall is received during the monsoon season. Researchers noted that there is change in distribution of this monsoon rainfall associated with climate change and global warming. This changing pattern in rainfall can be investigated by seasonality index (SI) of rainfall. Such studies are essential to identify the changes in runoff, infiltration, surface and groundwater management, agricultural planning,etc.Method:The variation in seasonality in rainfall over the Indian region is examined using monthly rainfall values for the period 1951 to 2015 of 34 meteorological sub-divisions excluding two Sea Islands. A seasonality index (SI) of a monthly rainfall is computed on monthly, seasonal (June to September) and annual scale. It is observed that seasonality index of rainfall of 34 sub-divisions for all months are in the range 0.37 (Jammu & Kashmir) to 1.56 (Saurashtra Kutch & Diu).Results:The results show that rainfall is markedly seasonal with a long dry season and most rainfall in less than three months. Most of the rainfall occurs in monsoon months. The seasonality index for monsoon season is computed and it varies from 0.19 (Nagaland, Manipur, Mizoram,Tripura) to 0.59 (Saurashtra Kutch & Diu) resulting in rainfall spread throughout the year, but with a definite wetter season.Conclusion:Trends of this index through the 65-year period are identified and indicate that seasonality is increasing in Uttaranchal, Himachal Pradesh, Gujarat Region-Dadra & Nagar Haveli; Saurashtra-Kutch & Diu, Konkan & Goa, Madhya Maharashtra, Marathwada, Chattisgarh, Tamilnadu & Pondicherry. The analysis clearly showed the climate change impact on northwest sub-divisions of the country showing increase in SI values leading to dryness during the monsoon season. The negative trend in SI values was observed in Sub- Himalayan West Bengal, Haryana-Delhi-Chandigarh, Punjab, Jammu & Kashmir, West and east Rajasthan, coastal Andhra Pradesh showing increasing wetness for an already wet months although rainfall occurs in a very short period of just a month or two.

Trend analysis of time series rainfall data using robust statistics

AbstractA temporal rainfall analysis was carried out for the study area, Rajahmundry city located in lower Godavari basin, India, during the period 1960–2013. Both the parametric and non-parametric approaches were envisaged for identifying the trends at different temporal scales. Linear and robust regression analysis revealed a negative trend at weekly scale during monsoon months, but failed to signify the slope at 95% confidence level. The magnitude of Sen's slope was observed to be negative during the months of April–September. Results of the Mann–Kendall test ascertained the negative rainfall trends during the monsoon months of June and July with a significant trend at 95% confidence interval. Application of robust statistics for long-term rainfall analysis helped to address the outlier's problem in the dataset. The Mann–Kendall test rejected the null hypothesis for all months except February–May and August after exclusion of outliers. Overall, a negative trend during monsoon season and a positive trend during post-monsoon season were observed using a robust non-parametric approach. Further, good correlation was found between the total rainfall and rainy days during the study period. On average, 21.25% days of a year is considered as rainy, while heavy and extreme rainfall in this region together occupies nearly 15% of the rainy days.

Reviving the “Ganges Water Machine”: where and how much?

Abstract. Runoff generated in the monsoon months in the upstream parts of the Ganges River basin (GRB) contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the potential for subsurface storage (SSS) in the Ganges basin to mitigate floods in the downstream areas and increase the availability of water during drier months. The Soil and Water Assessment Tool (SWAT) is used to estimate sub-basin water availability. The water availability estimated is then compared with the sub-basin-wise unmet water demand for agriculture. Hydrological analysis reveals that some of the unmet water demand in the sub-basin can be met provided it is possible to capture the runoff in sub-surface storage during the monsoon season (June to September). Some of the groundwater recharge is returned to the stream as baseflow and has the potential to increase dry season river flows. To examine the impacts of groundwater recharge on flood inundation and flows in the dry season (October to May), two groundwater recharge scenarios are tested in the Ramganga sub-basin. Increasing groundwater recharge by 35 and 65 % of the current level would increase the baseflow during the dry season by 1.46 billion m3 (34.5 % of the baseline) and 3.01 billion m3 (71.3 % of the baseline), respectively. Analysis of pumping scenarios indicates that 80 000 to 112 000 ha of additional wheat area can be irrigated in the Ramganga sub-basin by additional SSS without reducing the current baseflow volumes. Augmenting SSS reduces the peak flow and flood inundated areas in Ramganga (by up to 13.0 % for the 65 % scenario compared to the baseline), indicating the effectiveness of SSS in reducing areas inundated under floods in the sub-basin. However, this may not be sufficient to effectively control the flood in the downstream areas of the GRB, such as in the state of Bihar (prone to floods), which receives a total flow of 277 billion m3 from upstream sub-basins.

Analyzing the non-linear trend and multiscale teleconnections of regional monsoon indices using empirical mode decomposition

This paper first performs the analysis of linear and non-linear trends of four representative monsoon Indices namely Indian Monsoon Index (IMI) and Webster-Yang index (WYI), Western North Pacific Monsoon Index (WNPMI) and Australian Monsoon Index (AMI) for the period 1948–2015. The study evaluates the trend in the time series of different monsoon months and seasonal (JJA/JJAS/DJF) series, of all the indices using Mann–Kendall test, Sen’s slope method, linear fitting and the Empirical Mode Decomposition (EMD) method. The trend analysis showed significant reduction in all the series of WYI index and the August month series of IMI. The results of sequential version of MK test revealed that the WYI time series of different months and monsoon season showed statistically significant reduction in the past with differences in commencement year of statistical significance of MK value. The comparison of long term trend of monsoon indices and ElNino Southern Oscillation (ENSO) displayed an opposing trend for different indices except for WNPMI. Further for a detailed examination of association of different indices with ENSO in multiple time scales, the running correlations between the oscillatory modes of monsoon indices and ENSO are performed by employing the time dependent intrinsic correlation analysis. The association between ENSO and monsoon indices at different time scales is found to be strongly negative and consistent for WNPMI and AMI while for rest of the indices, the nature of association is found to be positive in inter annual and inter decadal time scales.

Performance Investigation of a Solar Heat Driven Adsorption Chiller under Two Different Climatic Conditions

The demand for cooling, especially in the developing economies, is rising at a fast rate. Fast-depleting sources of fossil fuel and environmental concerns necessitate looking for alternative cooling solutions. Solar heat driven adsorption based cooling cycles are environmentally friendly due to their use of natural refrigerants and the thermal compression process. In this paper, a performance simulation study of a basic two-bed solar adsorption chiller has been performed through a transient model for two different climatic locations in India. Effect of operating temperatures and cycle time on the chiller performance has been studied. It is observed that the solar hot water temperature obtained in the composite climate of Delhi (28.65°N, 77.25°E) can run the basic adsorption cooling cycle efficiently throughout the year. Whereas, the monsoon months of July and August in the warm and humid climate of Durgapur (23.48°N, 87.32°E) are unable to supply the required driving heat.

Wave spectral shapes in the coastal waters based on measured data off Karwar on the western coast of India

Abstract. An understanding of the wave spectral shapes is of primary importance for the design of marine facilities. In this paper, the wave spectra collected from January 2011 to December 2015 in the coastal waters of the eastern Arabian Sea using the moored directional waverider buoy are examined to determine the temporal variations in the wave spectral shape. Over an annual cycle for 31.15 % of the time, the peak frequency is between 0.08 and 0.10 Hz; the significant wave height is also relatively high (∼ 1.55 m) for waves in this class. The slope of the high-frequency tail of the monthly average wave spectra is high during the Indian summer monsoon period (June–September) compared to other months, and it increases with an increase in significant wave height. There is not much interannual variation in the slope for swell-dominated spectra during the monsoon, while in the non-monsoon period when wind-seas have a high level of influence, the slope varies significantly. Since the exponent of the high-frequency part of the wave spectrum is within the range of −4 to −3 during the monsoon period, the Donelan spectrum shows a better fit for the high-frequency part of the wave spectra in monsoon months compared to other months.

Assessing the performance of bias correction approaches for correcting monthly precipitation over India through coupled models

ABSTRACTThe objective of the present study was to investigate the inter‐annual variation and error structure in the prediction of monthly precipitation through two global coupled models, the National Centers for Environmental Prediction Climate Forecast System version 2 (CFSv2) and the Geophysical Fluid Dynamics Laboratory model. In view of the consistent systematic bias (dry bias during summer monsoon months and wet bias during pre‐monsoon months in CFSv2) a requirement to correct the inherent error is inevitable. For this purpose, a few bias correction methods, standardization−reconstruction (Z), quantile−quantile mapping (QQ) and nonlinear transformation (NL_Zi), are explored. The methods are applied to the outputs of the dynamic models and the efficiency is examined through different statistical skill measures. A maximum error reduction is noticed for March, July, September and December. A decreasing tendency for rainfall in July is represented by the raw model and its biased counterpart. The observed probability is noticed to be overestimated (underestimated) corresponding to below normal (above normal) precipitation in the raw model. The varying relationship between monthly precipitation and the NINO3.4 index might be a reason for misleading prediction during extreme years. Among the bias correction methods, NL_Zi showed maximum improvement in terms of predicting the precipitation amount and probability distribution all through the year irrespective of the selection of the coupled model.

UHF wind profiler observations of monsoon low-level jet (MLLJ) and its association with rainfall over a tropical Indian station

High resolution data of horizontal winds profiles (zonal and meridional) in the lower troposphere, derived from a UHF wind profiler at a tropical Indian station, Pune (18o 32’ N, 73o 51’ E, 559 masl) during a 3-yr period (June 2003-May 2006) has been utilized to study seasonal and intra-seasonal variability of winds. Winds display a systematic seasonal evolution with behavior opposite in phase in the two altitude regimes below and above a height of 4-5km. In the lower region, during the southwest monsoon months (June to September) winds are predominantly westerly with a peak in the 1.5-3.0km range indicating the occurrence of the monsoon low-level jet (MLLJ). Soon after September, winds in this height region change from westerly to easterly and these easterlies continue in winter months (December to February). Above a height of 4km, westerlies are observed during post-monsoon (October to November) and winter periods. The MLLJ is observed to be strong during normal/good monsoon years. On a day-to-day scale during southwest monsoon months, winds exhibit considerable intra-seasonal variability and periods of strong MLLJ seem to be associated with occurrence of spells of rainfall over the region.

Differential behaviour of a Lesser Himalayan watershed in extreme rainfall regimes

Climatic extremes including precipitation are bound to intensify in the global warming environment. The present study intends to understand the response of the Tons sub-watershed in Lesser Himalaya, in 3 years with entirely different hydrological conditions (July 2008–June 2011) in terms of discharge, sediment flux and denudation rates. Within an uncertainty limit of ±20%, the mean interannual discharge (5.74 ± 1.44 m 3 s −1) (±SE), was found highly variable (CV: 151%; 0.8–38 m 3 s −1). In a normal rainfall year (2008–2009; ∼1550 mm), the discharge was 5.12 ± 1.75 m 3 s −1, whereas in a drought year (2009–2010), it reduced by 30% with the reduction in ∼23% rainfall (CV: 85%). In an excessive rainfall year (once-in-a-century event) (2010–2011; ∼3050 mm), discharge as well as total solid load was ∼200% higher. Monsoon months (July–September) accounted for more than 90% of the annual solid load transport. The ratio of dissolved to suspended solid (C/P ratio) was consistently low (<1) during monsoon months and higher (1–7) during the rest of the dry period. C/P ratio was inversely (R 2=0.49), but significantly (P <0.001) related to the rainfall. The average mechanical erosion rate in the three different rainfall years was 0.24, 0.19 and 1.03 mmyr −1, whereas the chemical erosion was estimated at 0.12, 0.11 and 0.46 mmyr −1, respectively. Thus, the average denudation rate of the Tons sub-watershed has been estimated at 0.33 mmyr −1 (excluding extreme rainfall year: 1.5 mmyr −1). Our results have implications to understand the hydrological behaviour of the Lesser Himalayan watersheds and will be valuable for the proposed and several upcoming small hydropower plants in the region in the context of regional ecology and natural resource management.

Temperature during pregnancy influences the fetal growth and birth size

BackgroundBirth weight and length have seasonal fluctuations. However, it is uncertain which meteorological element has an effect on birth outcomes and which timing of pregnancy would explain such effect. Therefore, the purpose of this study was to examine temperature effects during pregnancy and which timing of pregnancy has effects on size at birth.MethodsA large, randomized, controlled trial of food and micronutrient supplementation for pregnant women was conducted in Matlab, Bangladesh (MINIMat Study), where women were enrolled from November 2001 to October 2003. The fetal growth data which included the size at birth and information of their mothers were obtained (n = 3267). Meteorological data such as temperature, precipitation, relative humidity, and daily sunshine hours during pregnancy were observed at the nearest observatory site of Bangladesh Meteorological Department.ResultsInfants born in colder months (November–January) were shorter than those born in hot and dry, and monsoon months (mean (SD) of birth length was 47.5 cm (2.2) vs. 47.8 cm (2.1) vs. 47.9 cm (2.1) respectively; P < 0.001). Increased temperature during the last month of pregnancy was significantly related with increased birth length with adjustment for gestational weeks and the season at birth, and remained significant with further adjustments for precipitation, sex of infants, maternal early-pregnancy BMI, parity, and education status of the mother (P < 0.01). On the other hand, increased temperature at mid-gestation was associated with increased birth weight (P < 0.05).ConclusionsThese findings suggest that temperature affects both birth weight and length. The more temperature increased at the last month of pregnancy, birth length became longer. For birth weight, the temperature at mid-pregnancy affected in a positive way.

CO variability and its association with household cooking fuels consumption over the Indo-Gangetic Plains

This study examines the spatio-temporal trends obtained from decade long (Jan 2003–Dec 2014) satellite observational data of Atmospheric Infrared Sounder (AIRS) and Measurements of Pollution in the Troposphere (MOPITT) on carbon monoxide (CO) concentration over the Indo-Gangetic Plains (IGP) region. The time sequence plots of columnar CO levels over the western, central and eastern IGP regions reveal marked seasonal behaviour, with lowest CO levels occurring during the monsoon months and the highest CO levels occurring during the pre-monsoon period. A negative correlation between CO levels and rainfall is observed. CO vertical profiles show relatively high values in the upper troposphere at ∼200 hPa level during the monsoon months, thus suggesting the role of convective transport and advection in addition to washout behind the decreased CO levels during this period. MOPITT and AIRS observations show a decreasing trend of 9.6 × 1015 and 1.5 × 1016 molecules cm−2 yr−1, respectively, in columnar CO levels over the IGP region. The results show the existence of a spatial gradient in CO from the eastern (higher levels) to western IGP region (lower levels). Data from the Census of India on the number of households using various cooking fuels in the IGP region shows the prevalence of biomass-fuel (i.e. firewood, crop residue, cowdung etc.) use over the eastern and central IGP regions and that of liquefied petroleum gas over the western IGP region. CO emission estimates from cooking activity over the three IGP regions are found to be in the order east > central > west, which support the existence of the spatial gradient in CO from eastern to the western IGP region. Our results support the intervention of present Indian government on limiting the use of biomass-fuels in domestic cooking to achieve the benefits in terms of the better air quality, household health and regional/global climate change mitigation.

Variation in rainfall trend at upstream - a threat towards filling schedule of Hirakud Reservoir, India

This study is focusing on the possibility of trend in monthly rainfall of upstream districts of the Hirakud reservoir of Mahanadi basin of Odisha applying Mann-Kendall test. Out of the other monsoon months, almost 19 districts show falling rainfall trend in September at 5% significance level. However, the inflow to reservoir shown declining trend during month of August and no trend in rest monsoon months. As the month of September is sensitive towards filling of reservoir as well as for flood control, the falling trends of rainfall will definitely put an alarm for the planner. The effect of climate change as well as changes in land use and storing/releases of upstream reservoir are suspected for the irregularities found in the pattern. The integrated basin management is also the call of the time for smooth operations of all the reservoirs.

Entomological determinants of malaria transmission in an epidemic prone area of District Nuh (Haryana state), India.

Entomological investigations were carried out in highly malarious villages under Ujina PHC of District Nuh (Haryana state) which is an epidemic prone area in northwestern region of India. The study was aimed to have an in-depth understanding of the entomological parameters influencing malaria transmission in the study area. The seasonal prevalence and biological attributes of vector mosquitoes were investigated during 2015 and 2016. Indoor resting vector mosquitoes were collected from human dwellings/cattle sheds and morphologically identified. Anopheles culicifacies were categorized to sibling species by species-specific inversions in polytene chromosomes and An. stephensi to ecological races on the basis of ridge number on egg float. The blood meal source analysis and incrimination studies of vectors were done by counter-current immunoelectrophoresis and enzyme-linked immunosorbent assay, respectively. Insecticide susceptibility test on vectors was performed as per WHO guidelines. Seasonal abundance of An. culicifacies and An. stephensi in the study area showed variation; the peak densities of both the vectors were observed during monsoon months which correlated well with the average monthly rainfall data. Though both vectors were found to be primarily zoophagic, the human blood index of An. culicifacies (HBI = 0.17) was significantly higher than that of An. stephensi (HBI= 0.02). Analysis of sibling species composition of An. culicifacies population showed that it comprised almost of sibling species A (>98%) which is an established malaria vector. Anopheles culicifacies was incriminated for Plasmodium vivax and P. falciparum circumsporozoite (CS) antigen during monsoon months in 2015 and 2016. Assessment of insecticide susceptibility status of malaria vectors against 0.5% deltamethrin revealed that An. culicifacies is more susceptible (95% mortality) than An. stephensi (85% mortality). The results suggest that An. culicifacies (species A) is playing a major role in malaria transmission in the study area and is almost susceptible to deltamethrin. Timely two rounds of indoor residual spray of synthetic pyrethroid with proper dosage and good coverage would be helpful in reducing vector population and consequently the malaria incidence. In addition, personal protection measures by the community would supplement the major intervention tool (IRS) in decreasing the man-vector contact.