9 research outputs found
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Not AvailableThe impact of projected climate change by 21st century on water requirements of rainfed monsoon and irrigated winter crops of arid Rajasthan has been studied. Crop water requirements were estimated from daily potential evapotranspiration at ambient and projected air temperature by 2020, 2050, 2080 and 2100 using modified Penman-Monteith equation and then by multiplying with crop coefficients. Crop water requirements in the region varied from 308 to 411 mm for pearl millet, 244 to 332 mm for clusterbean, 217 to 296 mm for green gram, 189 to 260 mm for moth bean, 173 to 288 mm for wheat and 209 to 343 mm for mustard. Further, due to global warming, if the projected temperatures rises by 40C, by the end of 21st century, water requirement in arid Rajasthan increases from the current level, by 12.9% for pearl millet and clusterbean, 12.8% for green gram, 13.2% for moth bean, 17.1% for wheat and 19.9% for mustard. The increased crop water requirements in the region, resulted in reduction in crop growing period by 5 days for long duration crops, but the crop acreage where rainfall satisfies crop water requirements, reduced by 23.3% in pearl millet, 15.2% in clusterbean, 6.7% in green gram, 13% in moth bean. The study reveals that the impact will be more severe on rabi crops than kharif crops, the rabi crops being dependent on depleting ground water resources in the region.Not Availabl
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Not AvailableThe impacts of elevated temperatures of 1 to 4°C on crop water requirements of major crops of arid Rajasthan have been studied. The seasonal crop water requirements were estimated by multiplying daily potential evapotranspiration (PET) with crop coefficients obtained from long-term lysimetric experiments conducted in the region. The daily PET was computed using modified Penman-Monteith equation with daily normal meteorological parameters. The spatial variation in daily PET in the region ranged from 2 mm in winter to 12 mm in summer and the annual PET varied between 1502 mm at Nagaur to 2221 mm at Jaisalmer. Water requirement of different crops in the region varied from 308 to 411 mm for pearl millet, 244 to 332 mm for clusterbean, 217 to 296 mm for green gram, 189 to 260 mm for moth bean, 173 to 288 mm for wheat and 209 to 343 mm for mustard. Further, a rise of 4°C in air temperature owing to global warming, increases ET requirement of arid zone crops over that of present level by 12-13% for kharif and 17-19% for rabi crops.Not Availabl
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Not AvailableThe rainfall characteristics and meteorological drought conditions in Jhunjhunu district of arid Rajasthan were studied using six tehsil-wise rainfall data (1901-2011). The district experiences 405 to 560 mm of annual rainfall in 26 to 34 rainy days with a coefficient of variation of 37 to 44%. The seasonal rainfall (June-September) varied from 343 to 477 mm in 18 to 24 rainy days. The highest annual rainfall recorded in the district was between 828 mm at Jhunjhunu and 1252 mm at Khetri. Similarly, the lowest rainfall record varied between 89 mm at Khetri and 187 mm at Udaipurwati. The extreme rainfall events recorded in the Jhunjhunu district showed that 1-day highest rainfall varied from 158 mm at Jhunjhunu to 281 mm at Khetri. The 1-day rainfall was lowest at Jhunjhunu (82.8 mm, 98.1 mm, 117.2 mm, 131.5 mm and 146.0 mm) and highest at Buhana (116.5 mm, 143.0 mm, 176.0 mm, 200.7 mm and 225.8 mm) for all return periods (5, 10, 25, 50 and 100 years). The long-term annual rainfall trends showed that there was a marginal increase at a rate 0.43 mm year-1 at Jhunjhunu, 0.48 mm year-1 at Khetri, 0.74 mm year-1 at Chirawa. The meteorological droughts prevailed in 36 years out of 111 years (1901-2011) with lowest frequency of 32 years with drought at Jhunjhunu and Chirawa to a highest frequency of 35 years drought at Khetri. The decade 1981-90 experienced highest (6 out of 10 years) number of moderate to severe droughts, whereas the 1941-50 recorded least frequency (2 out of 10 years) of droughts.Not Availabl
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Not AvailableThar Desert region of western Rajasthan which spreads in around 19.61 million ha, is very fragile and is
subjected to excessive stresses due to frequent drought and low rainfall, which occurs once in 2 or 3
years in the region, causing extreme stress to fauna due to limited seasonal grazing resources. The Inter Governmental Panel on Climate Change (IPCC, 2007) and the PRECIS model have projected hotter
days and warm nights and a reduction in rainfall in Thar region by 21st century. Such projected climate
change results in shifting rainfall pattern, higher temperatures, more demand for water and will be
significant driver of biodiversity with changing life cycles, loss, migration and invasion of new habitat
in Thar region. To understand the climate changes in Thar region, long-term trends in annual rainfall
and temperatures for Thar region were analyzed. The study showed that the air temperatures by the end
of 21st century are likely to increase by +3.3 OC at Bikaner, +3.4OC at Jaisalmer, +2.9OC at Jodhpur and
+2.5OC at Pali. Similarly, the annual rainfall of is likely to be increased by +100 mm at Bikaner, +124
mm at Jaisalmer, -40 mm at Jodhpur and +21 mm at Pali. The spatial and temporal variation in potential
evapotranspiration requirement of Thar region ranged from 2.1 mm/day to 12.2 mm/day and on an
annual basis between 1500 mm to 2220 mm. Further, the impact of projected air temperature upto a rise
of 4 OC by 21st century increases in evapotranspiration requirements by 9 to 23% during monsoon period
and 13-47% during winter period and such increased demand in water due to global warming will
reduce the water and feed resources of Thar region.Not Availabl
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Not AvailableThe rainfall characteristics and meteorological drought conditions in Sirohi District of Rajasthan were studied by analyzing the rainfall data (1901-2012) of three tehsils namely Reodar, Sirohi and Sheoganj. Three tehsils experience 520 to 621 mm of average annual rainfall in 24 to 27 days, out of which 482 to 580 mm occurs during June to September. The lowest annual rainfall in Sirohi was 140 mm in 1901 and highest of 1578 mm in 1973, whereas at Sheoganj, it varied from 157 mm in 1918 to 1689 mm in 1973 mm and at Reodar from 54 mm in 1987 to 1495 mm in 1973. The 1-day rainfall for return periods of 5, 10, 25, 50 and 100 years was 139.1, 168.8, 205.8, 233.4 and 261.6 mm at Sheoganj, 156.1, 192.7, 238.3, 272.3 and 307.0 mm at Reodar and 169.7, 209.5, 259.0, 296.0 and 333.7 mm at Sirohi. The long-term annual rainfall trends showed that there was an increase at a rate 0.62 mm year-1 at Sirohi, 0.24 mm year-1 at Sheoganj and 0.85 mm year-1 at Reodar. The severe meteorological droughts occurred in 11-12% years at Sirohi and Sheoganj and in 19% years at Reodar, whereas, mild drought in 23-29% and moderate drought in 19% years at all the locations.Not Availabl
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Not AvailableArid region is the home of drought and recurring features and one of the biggest truths for the region.
Whole arid western Rajasthan was never free from drought. Drought is a result of failure of rainfall from the
normal levels that supports livelihood of a region. Drought impacts both human and livestock population due to
failure of crops, depletion in surface and ground water resources. Between 1901 and 2010 western Rajasthan
experienced 58 moderate to severe droughts. There were five occasions when drought occurred in successive
years: 1903-05, 1957-60, 1966-71, 1984-87 and 1998-2000. Droughts of 1918, 1987 and 2002 were most
severe, when rainfall departure from the normal was -81, -65 and -70 percent, respectively. The districts of
Jaisalmer, Barmer, Bikaner and Ganganagar have the maximum probability of drought recurrence, even in
good rainfall years. Production of pearl millet, the major cereal crop of the region grown during kharif, is
reduced by 10-30% during mild drought, 35-60% during moderate drought and 75-90% during severe
droughts. Surface water availability also declined during drought years with the drought severity creating
drinking water problem. Fodder scarcity which is shorter by 20-30% of the demand during normal years,
touches 80-100% during severe droughts. Consequently, large-scale animal and human population migration
for food, fodder and water, as well as work takes place.Not Availabl
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Not AvailableThar desert region of India, which extends in more than 2.0 lakh sq. km area, experiences variable
rainfall from 100 mm to 450 mm in a year. Frequent drought, which occurs once in 2 or 3 years in the region,
causes extreme stress to fauna due to limited seasonal grazing resources. Besides xerophytic type of ecosystem, the fauna in Thar desert is subjected to extreme diurnal and seasonal variation in temperatures ranging as low as -5OC in winter to a high of +49OC in summer, causing thermal stress to the fauna. The Inter-Governmental Panel on Climate Change (IPCC, 2007) projected for hotter days and warm nights and a reduction in rainfall in Thar region by 21st century. Such projected climate change results in shifting rainfall pattern, higher temperatures, more demand for water and will be significant driver of biodiversity with changing life cycles, loss, migration and invasion of new habitat in Thar region. The present study on annual rainfall and temperature for Thar region showed by the end of 21st century, an increase in temperature by +3.8 OC at Bikaner, +3.6OC at Jaisalmer, +2.8OC at Jodhpur and +2.3OC at Pali, if the present rate of warming continues. Similarly, though there was no significant rise (@ 0.56 mm/year) in the annual rainfall of 12 arid districts of western Rajasthan, the annual rainfall is likely to be increased by +40 mm at Bikaner, +119 mm at Jaisalmer, -13 mm at Jodhpur and +43 mm at Pali. The spatial and temporal variation in potential evapotranspiration requirement of Thar region ranged from 2.1 mm/day to 12.2 mm/day and on an annual basis between 1500 mm to 2220 mm. During monsoon season, the impact of elevated temperatures on water demand is expected to increase by 0.1 to 0.5 mm/day for 1OC rise, 0.3 to 1.1 mm/day for 2OC, 0.4 to 1.6 mm/day for 3OC rise and 0.6 to 2.1 mm/day for a 4OC rise in temperature. Such increased demand of water due to global warming will reduce the scarce water and feed resources of Thar region.Not Availabl
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Not AvailableUsing Standardized Precipitation Index (SPI), an analysis on incidence and
severity of droughts occurred in arid Rajasthan during the period 1960-2009 showed
that the drought frequency varied from 32 years at Barmer to 24 years at Hanumangarh.
The decades 1960-1969, 1980-89 and 2000-2009 experienced highest number of moderate
and severe droughts. Year-wise and monthly SPI was also calculated for Barmer, Churu
and Jodhpur, to know drought severity during the cropping period of July, August
and September. To validate the SPI as a drought indicator, a multiple-linear regression
analysis between SPI of July, August and September as independent variables and pearl
millet grain yield as dependent variable was made. The regression model using SPI
predicted pearl millet yield up to 83% of Barmer district, 47% of Churu district and 62%
of Jodhpur district, thus the SPI is found useful as an indicator for monitoring drought
conditions in arid RajasthanNot Availabl
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Not AvailableThe rainfall characteristics, weekly water balance and meteorological drought conditions using six tehsil-wise rainfall data (1901-2005) in arid Jhunjhunu district were studied. The district experiences 399-556 mm of annual rainfall, 24-32 rainy days with a coefficient of variation of 37-44%. The seasonal rainfall (June-September) varied from 348-477 mm with 18-24 rainy days. The extreme rainfall events recorded in the Jhunjhunu district showed that 1-day highest was between 157.5 mm at Jhunjhunu to 281.4 mm at Khetri. 1-day highest rainfall was 91-117 mm once in 5-years to 167-226 mm once in 100 years. The long-term annual rainfall trends showed that there was a marginal increase at a rate by 12 mm/100 years at Jhunjhunu, 30 mm/100 years at Khetri, 56 mm/100 years at Chirawa and 100 mm/50 years at Udaipurwati. The meteorological droughts prevailed in 34 years out of 105 years (1901-2005). Thus, the frequency of occurrence of drought in the Jhunjhunu district varied from once in 3.6 years at Jhunjhunu to 3.0 years at Khetri. The other locations in the district experienced in 29 years at Chirawa. The drought frequency was highest during the decade 1981-90 with 6 out of 10 years recording moderate to severe drought and least frequency recording during 1941-50 with 2 out of 10 years as drought years.Not Availabl