Temperature In India Research Articles

Impact of climate change on agriculture: An Indian perspective

India is the seventh largest country of the world. In India temperature will increase 3oC to 6oC and rainfall will increase 15-30% in 21 Centaury. While the global surface temperature is projected to increase by 1-4oC from 2100 for low emission scenario and 2.5-5.8oC for higher emission scenario in the atmosphere. This Paper has been prepared with the objects of provide key information on the impacts of climate on Indian agriculture. The greenhouses gas emissions increases day by day in the atmosphere from the many sources such as industrial sources crop production and fossil fuel combustion. These are the major sources for the climate change. The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land use change, while those of methane and nitrous oxide are primarily due to agriculture. Currently Available general circulation models (GCMs) suggest that the area-averaged annual mean warming would be about 3°C in the decade of the 2050s and about 5°C in the decade of the 2080s over the land regions of Asia as a result of future increases in atmospheric concentration of greenhouse gases. In Rajasthan, a 2°C rise in temperature was estimated to reduce production of pearl millet by 10-15 per cent (Y S Ramakrishna et al.,). The state of Madhya Pradesh, where soybean is grown on 77 per cent of all agricultural land, could dubiously benefit from an increase in carbon dioxide in the atmosphere.

Long-term changes and variability of monthly extreme temperatures in India

Extreme temperatures are changing worldwide together with changes in the mean temperatures. This study investigates the long-term trends and variations of the monthly maximum and minimum temperatures and their effects on seasonal fluctuations in various climatological regions in India. The magnitude of the trends and their statistical significance were determined by parametric ordinary least square regression techniques and the variations were determined by the respective coefficient of variations. The results showed that the monthly maximum temperature increased, though unevenly, over the last century. Minimum temperature changes were more variable than maximum temperature changes, both temporally and spatially, with results of lesser significance. The results of this study are good indicators of Indian climate variability and its changes over the last century.

Impact of aerosol optical depth on seasonal temperatures in India: a spatio‐temporal analysis

The third assessment report of the Intergovernmental Panel on Climate Change (IPCC) describes the clear modulating effect of aerosols both directly and indirectly on the prevailing climatic conditions on the Earth's surface. Several studies have noted higher than average concentrations of aerosols over the densely populated Indian subcontinent and adjacent regions. The study focuses on seasonal‐level spatial patterns of aerosol optical depth (AOD) concentrations and their relationship with near‐surface air temperatures. The period of analysis includes the years 2000 to 2005 for the summer monsoon season, and 2001 to 2005 for the winter season. The overall patterns of AODs show higher concentrations over the densely populated and highly industrialized Gangetic basin for bot9h seasons. The AOD–temperature relationship was predominantly negative, meaning that higher AOD concentrations resulted in lower temperatures for both seasons over northeastern India and the west coast, in the vicinity of Mumbai. Temperatures in the interior northwestern sector of the subcontinent, extending northwards towards Kashmir, experienced positive forcing during the summer season. The winter‐season relationship was predominantly negative, whereas during the summer monsoon season it was neutral to positive. The differences in responses may be attributed to the impact of overcast skies and heavy precipitation during the summer monsoon season, leading to longwave radiation being trapped inside the Earth's atmosphere, producing higher minimum temperatures. However, predominantly clear skies during the winter season resulted in a negative forcing by aerosols on the surface temperatures.

Impacts of the agricultural Green Revolution–induced land use changes on air temperatures in India

India has one of the most intensive and spatially extensive irrigation systems in the world developed during the1960s under the agricultural Green Revolution (GR). Irrigated landscapes can alter the regional surface energy balance and its associated temperature, humidity, and climate features. The main objective of this study is to determine the impacts of increased irrigation on long‐term temperature trends. An analysis of the monthly climatological surface data sets at the regional level over India showed that agriculture and irrigation can substantially reduce the air temperature over different regions during the growing season. The processes associated with agriculture and irrigation‐induced feedback are further diagnosed using a column radiation‐boundary layer model coupled to a detailed land surface/hydrology scheme, and 3‐D simulations using a Regional Atmospheric Modeling System. Both the modeling and observational analysis provide evidence that during the growing season, irrigation and agricultural activity are significantly modulating the surface temperatures over the Indian subcontinent. Therefore irrigation and agricultural impacts, along with land use change, and aerosol feedbacks need to be considered in regional and global modeling studies for climate change assessments.

Some evidence of climate change in twentieth-century India

The study of climate changes in India and search for robust evidences are issues of concern specially when it is known that poor people are very vulnerable to climate changes. Due to the vast size of India and its complex geography, climate in this part of the globe has large spatial and temporal variations. Important weather events affecting India are floods and droughts, monsoon depressions and cyclones, heat waves, cold waves, prolonged fog and snowfall. Results of this comprehensive study based on observed data and model reanalyzed fields indicate that in the last century, the atmospheric surface temperature in India has enhanced by about 1 and 1.1°C during winter and post-monsoon months respectively. Also decrease in the minimum temperature during summer monsoon and its increase during post-monsoon months have created a large difference of about 0.8°C in the seasonal temperature anomalies which may bring about seasonal asymmetry and hence changes in atmospheric circulation. Opposite phases of increase and decrease in the minimum temperatures in the southern and northern regions of India respectively have been noticed in the interannual variability. In north India, the minimum temperature shows sharp decrease of its magnitude between 1955 and 1972 and then sharp increase till date. But in south India, the minimum temperature has a steady increase. The sea surface temperatures (SST) of Arabian Sea and Bay of Bengal also show increasing trend. Observations indicate occurrence of more extreme temperature events in the east coast of India in the recent past. During summer monsoon months, there is a decreasing (increasing) trend in the frequency of depressions (low pressure areas). In the last century the frequency of occurrence of cyclonic storms shows increasing trend in the month of November. In addition there is increase in the number of severe cyclonic storms crossing Indian Coast. Analysis of rainfall amount during different seasons indicate decreasing tendency in the summer monsoon rainfall over Indian landmass and increasing trend in the rainfall during pre-monsoon and post-monsoon months.

Evidence of climate jump in annual temperature in India

Annual mean temperature of 50 well-distributed stations in India is analyzed for trend and climate jump. Four statistical tests are used to detect the climate jump. Table-look-up test, which is more appropriate than ‘t’ test for time series data, has been applied for the first time to detect the climate jump. Sudden changes in climate are noticed by getting discontinuities or jump in annual mean temperature of most of the stations. It was found that while the northern India received climate jump much earlier i.e. during the decade 1931-1940, extreme south Peninsular India received climate jump between 1961-63.

Long‐term trends of surface air temperature in india

AbstractSalient features of the long‐term variation of surface air temperature for India as a whole and for different regions of the country have been presented. Temperature data at 73 fairly widespread stations, for the period 1901‐1982. have been used in the study. Seasonal and annual temperature anomaly series have been obtained for the different regions. Such series have also been obtained for latitude‐ and longitude‐wise classifications. The long‐term variation in the temperature has been evaluated by linear trend.The results indicate a slight but definite warming trend in the mean annual Indian temperatures. This warming is found to be mainly contributed by the post‐monsoon and winter seasons. West coast, interior peninsula, north central and north‐east regions of the country have shown pronounced warming in the mean annual temperatures. The post‐1940 cooling reported for the Northern Hemisphere is not conspicuous in the mean annual Indian temperature anomalies.

Fluctuations in the seasonal oscillations of temperature in India

Statistical analysis of the time series of the mean annual temperature and characteristic parameters representing seasonal variation of temperature over 8 representative stations of India has been made Mean annual temperature shows an increasing trend at Calcutta, Bombay, Bangalore and Allahabad and decreasing trend at Fort Cochin Quasi-biennial oscillation is a significant feature of the temperature variation not only in the mean annual temperature but also in the amplitude of the seasonal variation of the temperature of the different parts of the country.

Seasonal Oscillations of daily mean Maximum Temperature in India and neighbourhood

The mean daily maximum temperatures of 124 selected observatories have been subjected to harmonic analysis, The annual oscillations are observed to predominate over the other harmonic oscillations. The amplitudes of annual oscillation are highest in northwest of India and least over the west coast, Half-yearly oscillation amplitudes are highest over central India more towards northern latitudes, The close proximity of the dates of onset of SW monsoon and amplitude maxima of the annual oscillations over a major part in northwest India and adjoining area is striking.
 
 The regression coefficients of the first and second harmonic amplitude with latitude, longitude and elevation have been worked out and discussed.

Seasonal Oscillation of the Diurnal Range of Temperature in India and neighbourhood

The seasonal oscillation of the diurnal aperiodic amplitude of air temperature at 4 ft above ground has been studied with reference to the data of 167 climatological stations in India and neighbourhood.
 
 It has been found that the annual and half yearly oscillations account for nearly 90-95 per cent of the variation except at a very few stations associated with special features.
 
 The amplitude of the annual oscillation is largest (9-10°F) over a track extending from the Gulf of Cambay on the west to Bihar on the east and decreases towards the coast and towards the Himalayas. The maximum in the oscillation occurs generally in February; the notable exception being the southeast Peninsula where it is very much delayed being as late as May and over the Coromandel coast.
 
 The half yearly amplitude is much smaller in magnitude with highest values of 4-5°F over the northwestern part of the country decreasing towards the coast and the Himalayas the maximum in the oscillation occurs generally in May advancing by two to three months in the south Peninsula outside the west coast.
 
 Regression equations for representing distribution of the components of the two oscillations as linear functions of latitude longitude, and elevation have been derived. The fit of these representations has been found to be fairly good in the case of the annual and half-yearly amplitudes and genera angles of the annual oscillation. The significance of the gradients with respect to the positional co-ordinates have been discussed.

Seasonal Oscillations of air temperature in India and neighbourhood

The annual and the half-yearly oscillations in the mean temperature of air at 4 feet above ground level at 167 meteorological stations in India and neighbourhood. have been separated. The dependence of the components of the vectors of the different Oscillations on the location of the stations have been determined. Regression equations for representing the components of the oscillations as a linear function of latitude, longitude and elevation have been derived. The fit of these representations has been found to be fairly good, the correlation between the actual and the calculated values being of the order of 0. 8 to 0. 9 generally. The significance of the gradients with respect to the positional co-ordinates have been discussed.
 

Climatic changes in India – (III) pressure

The authors (1951,1954) have studied the changes in raiinfall and temperature in India and the present note consists of a similar study regarding pressure.
 
 

Maximum dew-point temperature in India

The moisture content of an air mass over a station depends upon the dew-point at the station and the higher the dew-point, the higer is the moisture content of the air mass. A knowledge of the maximum possible dew-point at a place is thus necessary for estimating the maximum possible precipitation.

Radiology vs. the Monsoon: Effect of Climate upon Equipment

The present communication is intended for those who are interested in the physical and technical aspects of radiology. Radiologists whose concern in their specialty is purely medical need read no further, for it is our purpose to discuss the behavior of x-ray equipment exposed to unusual climatic conditions. Before presenting our experiences, it seems fair to state that the apparatus used in our department was not meant for operation in a monsoon area alone. The global aspects of World War II made it necessary to employ the same equipment under climatic conditions of all sorts. Nevertheless, these machines have given excellent service no matter where used. The wide variations in the humidity and temperature in India produced defects and failures in our equipment which we believe are worth recording. Whereas none of these “breakdowns” was considered a major problem, they did cause trouble and had to be recognized and rectified. It is with the hope that our experiences may help others working in a similar c...

Scientific Serials

Journal of the Asiatic Society of Bengal, vol. 1. part 2, No. 2 1881 (July 30), contains:—H. F. Blanford, F.R.S., on the relations of cloud and rainfall to temperature in India, and on the opposite variations of density in the higher and lower atmospheric strata, and description of a rain-gauge with evaporimeter for remote and secluded stations (plate 15).—J. Wood-Mason, on some insects belonging to the Rhopalocera from India and Burmah.—W. T. Blanford, F.R.S., on the Voles (Arvicola) of the Tibet Himalayas and Afghanistan (plates 1 and 2); and on Myospalax fuscicapillus, Blyth.

Barometric Pressure and Temperature in India

IN order to satisfy myself as to whether some of Mr. Broun's conclusions (NATURE, vol. xix. p. 6) held good when inland stations were included in the comparison, I recently examined in detail the pressure and temperature oscillations at fifty-one stations in the Indian peninsula, computed from the means given in Mr. Blanford's “Indian Meteorologist's Vade Mecum.” As these stations represent every part of the country, the results afford a basis for deduction of sufficient extent to be reliable.

LXXIV. Note on a recent fossil freshwater deposit in southern India, with a few remarks on the origin and age of the kunker, and on the supposed decrease of thermal temperature in India

LXXIV. <i>Note on a recent fossil freshwater deposit in southern India, with a few remarks on the origin and age of the kunker, and on the supposed decrease of thermal temperature in India</i>