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The Missouri River Basin (MRB) is the largest river basin in the U.S. and is one of the most important crop and livestock-producing regions in the world. In a previous study of associations between decadal climate variability (DCV...
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The Missouri River Basin (MRB) is the largest river basin in the U.S. and is one of the most important crop and livestock-producing regions in the world. In a previous study of associations between decadal climate variability (DCV) phenomena and hydro-meteorological (HM) variability in the MRB for the March-August period, and their impacts on stream flow in the MRB, it was found that positive and negative phases of the Pacific Decadal Oscillation (PDO), the tropical Atlantic sea-surface temperature gradient variability (TAG), and the west Pacific Warm Pool (WPWP) temperature variability were significantly associated with decadal variability in precipitation and surface air temperature in the MRB, with combinations of various phases of these DCV phenomena associated with dry, wet, or neutral HM conditions. It was also found that these DCV phenomena impact stream flow in the MRB substantially via their association with MRB hydro-meteorology. In the present study, the Erosion Productivity Impact Calculator model, also known as the Environmental Policy Integrated Climate (EPIC) model, calibrated and validated for the MRB, was used to simulate yields of dryland corn (Zea mays L) and spring and winter wheat (Triticum aestivum L), in response to HM anomalies associated with the three DCV phenomena. Realistic values of indices of the three DCV phenomena have major impacts on crop yields, as much as 40-50% of average yield in some locations in the MRB and also evident in MRB-aggregated crop yields; however, our results show that the impacts can be location-specific. Since each of the three DCV phenomena can persist in one phase or another for several years to a decade or longer, and since the simultaneous correlation among these phenomena is negligibly small, their combined and cumulative positive/negative effects on the MRB HM and agricultural production can be dramatic in this major American and global "bread basket". In addition, EPIC's success in simulating long-term crop yields in the MRB, taking technology trends into account, suggests that, if the evolution of major DCV phenomena can be forecast, it may be possible to forecast, as well, some multiyear to decadal measure of crop yields in the MRB with some skill. (C) 2011 Elsevier B.V. All rights reserved.
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摘要 :
The Missouri River Basin (MRB) is the largest river basin in the U.S. and is one of the most important crop and livestock-producing regions in the world. In a previous study of associations between decadal climate variability (DCV...
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The Missouri River Basin (MRB) is the largest river basin in the U.S. and is one of the most important crop and livestock-producing regions in the world. In a previous study of associations between decadal climate variability (DCV) phenomena and hydro-meteorological (HM) variability in the MRB for the March-August period, and their impacts on stream flow in the MRB, it was found that positive and negative phases of the Pacific Decadal Oscillation (PDO), the tropical Atlantic sea-surface temperature gradient variability (TAG), and the west Pacific Warm Pool (WPWP) temperature variability were significantly associated with decadal variability in precipitation and surface air temperature in the MRB, with combinations of various phases of these DCV phenomena associated with dry, wet, or neutral HM conditions. It was also found that these DCV phenomena impact stream flow in the MRB substantially via their association with MRB hydro-meteorology. In the present study, the Erosion Productivity Impact Calculator model, also known as the Environmental Policy Integrated Climate (EPIC) model, calibrated and validated for the MRB, was used to simulate yields of dryland corn (Zea mays L) and spring and winter wheat (Triticum aestivum L), in response to HM anomalies associated with the three DCV phenomena. Realistic values of indices of the three DCV phenomena have major impacts on crop yields, as much as 40-50% of average yield in some locations in the MRB and also evident in MRB-aggregated crop yields; however, our results show that the impacts can be location-specific. Since each of the three DCV phenomena can persist in one phase or another for several years to a decade or longer, and since the simultaneous correlation among these phenomena is negligibly small, their combined and cumulative positive/negative effects on the MRB HM and agricultural production can be dramatic in this major American and global "bread basket". In addition, EPIC's success in simulating long-term crop yields in the MRB, taking technology trends into account, suggests that, if the evolution of major DCV phenomena can be forecast, it may be possible to forecast, as well, some multiyear to decadal measure of crop yields in the MRB with some skill. (C) 2011 Elsevier B.V. All rights reserved.
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Gujarat, being a coastal state, is likely to be impacted by global warming and climate change not only due to sea level rise and salinity ingress but also due to an increase in the frequency of cyclonic storms and other extreme we...
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Gujarat, being a coastal state, is likely to be impacted by global warming and climate change not only due to sea level rise and salinity ingress but also due to an increase in the frequency of cyclonic storms and other extreme weather events, causinguncertainty in crop production. An attempt has therefore been made to understand the climate of Gujarat in the past, present, and future based on the works done at the Department of Agricultural Meteorology, Anand. Analysis carried out on climatic trends and climatic extremes using past available data from different stations in Gujarat has been highlighted. Crop simulation models validated with experimental data collected for different crops across Gujarat state were used to understand the response ofcrops to climatic variability. The climate change impact studies and adaptation strategies carried out under the NPCC project have also been highlighted. And lastly, the work done by the author as an emeritus scientist on climate projections under RCP 4.5 and RCP 8.5 for all the districts of Gujarat and their likely impact on selected crops is presented. The results revealed that in the past, temperatures have shown increasing trends but not reached significant levels except at certain locations at night. Rainfall has also increased, but marginally. Future temperatures have been projected to increase in different parts of Gujarat under RCP4.5 and RCP8.5 with varying magnitudes. Similarly, the rainfall has also been projected to increase, while the sunshine hours are projected to decrease. The ultimate impact would be a drastic reduction in yields in spite of the increase in CO_2 level, suggesting that the present-day crop varieties would not be able to sustain crop production levels under a changing climatic scenario.
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Reisner et al. revisited a study we had done modeling the climate impacts of a nuclear war between India and Pakistan, in which fires started by 100 15-kt atomic bombs would produce 5 Tg of soot injected into the upper troposphere...
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Reisner et al. revisited a study we had done modeling the climate impacts of a nuclear war between India and Pakistan, in which fires started by 100 15-kt atomic bombs would produce 5 Tg of soot injected into the upper troposphere, and subsequently lofted into the lower stratosphere. Their claim that there would be much less smoke than in our results is wrong for several reasons. They chose a target area of suburban Atlanta that includes a golf course, playground, and individual houses with large yards, with little material to burn, which is not representative of densely populated cities in India and Pakistan. The fire they modeled is not typical of the type of mass fire likely to result from a nuclear attack on cities. They used winds that are stronger than typical winds. They did not allow moist convection, which would be important in convective lofting of the smoke. Their claim that if they included convection the resulting rain would wash out the smoke is not supported by observations of pyrocumulonimbus injection of smoke into the stratosphere from forest fires. And they used a fire model that they have not made available for other scientists to try to reproduce their work, and which has not been shown to accurately simulate firestorms observed in Hamburg, Dresden, and Hiroshima during World War II. They significantly underestimate the amount of smoke, and climate and agricultural impacts likely after a nuclear war.
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The impact of climate change between 2000 and 2095 SRES A2 climates on surface ozone (O)3 and on O3 source-receptor (S-R) relationships is quantified using three coupled climate-chemistry models (CCMs). The CCMs exhibit considerab...
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The impact of climate change between 2000 and 2095 SRES A2 climates on surface ozone (O)3 and on O3 source-receptor (S-R) relationships is quantified using three coupled climate-chemistry models (CCMs). The CCMs exhibit considerable variability in the spatial extent and location of surface O3 increases that occur within parts of high NOx emission source regions (up to 6 ppbv in the annual average and up to 14 ppbv in the season of maximum O3). In these source regions, all three CCMs show a positive relationship between surface O3 change and temperature change. Sensitivity simulations show that a combination of three individual chemical processes-(i) enhanced PAN decomposition, (ii) higher water vapor concentrations, and (iii) enhanced isoprene emission-largely reproduces the global spatial pattern of annual-mean surface O3 response due to climate change (R2 = 0.52). Changes in climate are found to exert a stronger control on the annual-mean surface O3 response through changes in climate-sensitive O3 chemistry than through changes in transport as evaluated from idealized CO-like tracer concentrations. All three CCMs exhibit a similar spatial pattern of annual-mean surface O3 change to 20% regional O3 precursor emission reductions under future climate compared to the same emission reductions applied under present-day climate. The surface O3 response to emission reductions is larger over the source region and smaller downwind in the future than under present-day conditions. All three CCMs show areas within Europe where regional emission reductions larger than 20% are required to compensate climate change impacts on annual-mean surface O3.
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Saharan cyclones are an important feature of the seasonal spring climate of Saudi Arabia. It was found in an objectively tracking scheme that of 688 Sahara tracks, 53 of them reached Saudi Arabia during the period 1958–2018. Two ...
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Saharan cyclones are an important feature of the seasonal spring climate of Saudi Arabia. It was found in an objectively tracking scheme that of 688 Sahara tracks, 53 of them reached Saudi Arabia during the period 1958–2018. Two distinct regions of cyclogenesis are identified: the first is Area A (Algeria, in particular, south of the Atlas Mountains) and the second is Area B (Libya and Egypt). The 53 tracks that pass or abate over Saudi Arabia are ultimately categorized into five key routes. The Saharan cyclones intensify near or over the Mediterranean, developing a relatively strong pressure gradient during their lifetimes which weakens as they pass over the Arabian Peninsula. Cyclones develop usually under a tropical trough over North Africa, which is accompanied by a thermal ridge with a very strong temperature gradient. This pattern is also found at upper levels of the atmosphere. During the cyclones’ movement over Saudi Arabia, they extend upwards, and at higher levels, pressure levels of up to 500?hPa can be observed. The study also revealed that more tracks occur during the negative phase of the North Atlantic Oscillation, reflecting the role played by subtropical high pressure in controlling the movement of the Saharan cyclones. Cyclones originating over Area B are more frequent in recent decades than in the earlier decades. Cyclones originating in Area B are found to have more influence on the climate of Saudi Arabia than those occurring in Area A. Saharan cyclones that reach Saudi Arabia substantially increase the frequency of dust storms, raise the minimum temperature and maximum wind speed, and cause a reduction in minimum visibility. These results suggest how they may contribute to weather forecasts for the region.
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Frequent and intense natural calamities, sea level rises and salinity have been causing adverse impacts on economic, environmental and social aspects of hundreds of millions people across the world. Although a series of studies wa...
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Frequent and intense natural calamities, sea level rises and salinity have been causing adverse impacts on economic, environmental and social aspects of hundreds of millions people across the world. Although a series of studies was undertaken on social and environment impacts, very little information is available on power generation affected by climate change. The power generation in developing countries, especially Bangladesh, whose existence is severely threatened by the rise of sea levels, salinity, the ambient temperature, drought and flood, is not well studied and reported. Therefore, the primary objective of this study was to identify the risks imposed by global climate change on existing and projected power generation in Bangladesh. The climate effect parameters and their impacts on power generation capacity are studied and analysed. The findings indicate that all existing and future power plants and their generation across the country will be affected by global climate change.
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Multiple persistent jet aviation contrails - contrail 'outbreaks' - occur frequently over certain portions of the Continental United States (CONUS). The artificial cloudiness generated by contrail outbreaks alters the atmospheric ...
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Multiple persistent jet aviation contrails - contrail 'outbreaks' - occur frequently over certain portions of the Continental United States (CONUS). The artificial cloudiness generated by contrail outbreaks alters the atmospheric radiation budget, potentially impacting the surface air temperature, particularly the diurnal temperature range (DTR), or difference between daytime maximum and nighttime minimum temperatures. This study evaluates the hypothesis that contrail outbreaks reduce the DTR relative to clear-sky conditions. We utilize a database of longer-lived (>4 h duration) jet contrail outbreaks for the CONUS previously determined from interpretation of high-resolution satellite imagery, for the January and April months of 2008 and 2009. The outbreak impact on DTR was determined by comparing maximum and minimum temperatures at pairs of surface weather stations (one outbreak and one non-outbreak) across two regions of climatologically high outbreak frequency; the South in January, and Midwest in April. We ensured that each station pair selected had broadly similar land use-land cover, soil moisture, and synoptic air mass conditions. For outbreaks in the South (January), there was a statistically significant reduction of DTR at the outbreak versus non-outbreak stations. This result was similar to that obtained for a smaller subset of outbreaks for which lower-level clouds could be confirmed as being absent (from North American Regional Reanalysis (NARR) output). For the Midwest (April), the results are mixed; statistically different for satellite-retrieved outbreaks, but not significantly different for the NARR-validated dataset. These results suggest that persistent jet contrails should be considered in short-term weather forecasting, and for their potential influence on the climatology of more frequently impacted areas.
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Climatic anomalies can pose severe challenges for farmers and resource managers. This is particularly significant with respect to gradually developing anomalies such as droughts. The impact of the 1995–1996 drought on the Oklahom...
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Climatic anomalies can pose severe challenges for farmers and resource managers. This is particularly significant with respect to gradually developing anomalies such as droughts. The impact of the 1995–1996 drought on the Oklahoma wheat crop, and the possibility that predictive information might have reduced some of the losses, is examined through a combined modeling approach using climatological data and a crop growth model that takes into account an extensive range of soil, climatic, and plant variables. The results show potential outcomes and also illustrate the point at which all possible climatic outcomes were predicting a significantly low wheat yield. Based on anecdotal evidence of the 1995–1996 drought, which suggested that farmers who planted at different times experienced different yields, the model was run assuming a variety of different planting dates. Results indicate that there is indeed a noticeable difference in the modeled wheat yields given different planting dates. The information regarding effectiveness of planting date can be used in conjunction with current long-range forecasts to develop improved predictions for the current growing season. This approach produces information regarding the likelihood of extreme precipitation events and the impact on crop yield, which can provide a powerful tool to farmers and others during periods of drought or other climatic extremes.
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The study attempts to estimate the potential impact of climate change on rice production in Guntur district using ORYZA 2000 model. The simulation has been performed under potential production situation for variety BPT 5204. The r...
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The study attempts to estimate the potential impact of climate change on rice production in Guntur district using ORYZA 2000 model. The simulation has been performed under potential production situation for variety BPT 5204. The results also showed that the increase in C0_2 concentration under future climate is conducive to raise the rice yield, but it still cannot compensate the negative effect of climate warming. The cultivar showed different reaction to temperature raise and C0_2 fertilization during model simulation, indicating that the difference of yield variation is affected not only by climatic factors, but also by the genetic characteristics of rice variety.
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