{"title":"A new version of the reconnaissance drought index, N-RDI","authors":"MM Ghasemi, A. Zarei, M. Mokarram","doi":"10.3354/cr01705","DOIUrl":"https://doi.org/10.3354/cr01705","url":null,"abstract":"","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75595257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Ajay, Binita Pathak, P. Bhuyan, F. Solmon, F. Giorgi
Over the last few decades, there have been substantial changes in sectoral anthropogenic emissions over India, modifying the region’s air quality and radiation budget. However, these sectoral contributions are still poorly understood. This study attempts to estimate the anthropogenic aerosols and SO2 emissions from different sectors over the Indian subcontinent and their implications for regional climate and human health using the RegCM4.4 regional climate model and the Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) global model. We consider current emissions as well as emissions with a mitigation scenario for the year 2030. The RegCM simulations with ECLIPSE v5a as emissions inventory for 2000 and 2015 show high SO2 emissions from the energy sector, substantially contributing to anthropogenic aerosol optical depth (AODanthro) and climate forcing. The residential and transport sectors’ imprint on climate forcing is increased in 2015 compared to 2000. Higher AODanthro (0.35-0.45) occurrence days substantially decrease under a mitigation scenario by 5-10% over the Indo-Gangetic Plain. In particular, over 5�megacities (Delhi, Kolkata, Mumbai, Chennai, and Bangalore) of India, the concentrations of black carbon, organic carbon, and particulate matter ≤2.5 µm in diameter (PM2.5) are substantially reduced under the mitigation scenario; however, SO2 is increased. The reduction of pollutants contributes to significantly reducing life expectancy loss in all cities. This study advocates the need for future emission control policies with a synergy between air quality and climate change.
{"title":"Sectoral emissions contributions to anthropogenic aerosol scenarios over the Indian subcontinent and effects of mitigation on air quality, climate, and health","authors":"P. Ajay, Binita Pathak, P. Bhuyan, F. Solmon, F. Giorgi","doi":"10.3354/cr01671","DOIUrl":"https://doi.org/10.3354/cr01671","url":null,"abstract":"Over the last few decades, there have been substantial changes in sectoral anthropogenic emissions over India, modifying the region’s air quality and radiation budget. However, these sectoral contributions are still poorly understood. This study attempts to estimate the anthropogenic aerosols and SO2 emissions from different sectors over the Indian subcontinent and their implications for regional climate and human health using the RegCM4.4 regional climate model and the Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) global model. We consider current emissions as well as emissions with a mitigation scenario for the year 2030. The RegCM simulations with ECLIPSE v5a as emissions inventory for 2000 and 2015 show high SO2 emissions from the energy sector, substantially contributing to anthropogenic aerosol optical depth (AODanthro) and climate forcing. The residential and transport sectors’ imprint on climate forcing is increased in 2015 compared to 2000. Higher AODanthro (0.35-0.45) occurrence days substantially decrease under a mitigation scenario by 5-10% over the Indo-Gangetic Plain. In particular, over 5�megacities (Delhi, Kolkata, Mumbai, Chennai, and Bangalore) of India, the concentrations of black carbon, organic carbon, and particulate matter ≤2.5 µm in diameter (PM2.5) are substantially reduced under the mitigation scenario; however, SO2 is increased. The reduction of pollutants contributes to significantly reducing life expectancy loss in all cities. This study advocates the need for future emission control policies with a synergy between air quality and climate change.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76566406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Choosing the right harvesting strategy is crucial for sustainable utilization of biological resources but is challenging in real systems with fluctuating environments. This challenge is expected to become even greater with global warming, as environmental variability is predicted to increase. Additionally, harvesting strategies based on single-species models have been shown to carry a severe risk of species extinctions when species interactions are ignored, particularly in systems with more than one harvested species. As the climate continues to warm, we therefore need new reference points for harvesting in an ecosystem context with environmental fluctuations. In this paper, we discuss the development of harvesting strategies and suggest that a proportional threshold harvesting framework could be a useful starting point for developing such reference points and tackling the challenge of sustainable harvesting in the future.
{"title":"Optimal harvesting in a changing climate","authors":"A. Lee, B. Sæther","doi":"10.3354/CR01658","DOIUrl":"https://doi.org/10.3354/CR01658","url":null,"abstract":"Choosing the right harvesting strategy is crucial for sustainable utilization of biological resources but is challenging in real systems with fluctuating environments. This challenge is expected to become even greater with global warming, as environmental variability is predicted to increase. Additionally, harvesting strategies based on single-species models have been shown to carry a severe risk of species extinctions when species interactions are ignored, particularly in systems with more than one harvested species. As the climate continues to warm, we therefore need new reference points for harvesting in an ecosystem context with environmental fluctuations. In this paper, we discuss the development of harvesting strategies and suggest that a proportional threshold harvesting framework could be a useful starting point for developing such reference points and tackling the challenge of sustainable harvesting in the future.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88106357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Herfindal, A. Lee, S. Hamel, E. Solberg, B. Sæther
Harvesting can have a substantial impact on population dynamics and individual performance in wild populations. While the direct consequences of harvest on individual survival and population growth rate are often apparent, harvesting can also have indirect and more subtle demographic consequences. Disentangling these consequences, however, requires in-depth knowledge of individual life histories of both females and males in the population. Here, we summarise demographic research on a population where such data exist: the Vega moose population in northern Norway. In this population, vital rates vary considerably among both females and males, and harvesting increases this variation by generating positive covariation between reproductive performance and survival. The skewed age and sex structure, which is typical of many harvested populations, also has demographic consequences: it reduces the ratio of effective to total population size and influences variation in vital rates in males and females. The moose harvest at Vega is structured by age- and sex-specific quotas, but it is not intentionally selective regarding size or other phenotypic characteristics. Still, harvest selection for earlier birth rates and larger calves was apparent, likely due to habitat-performance relationships and habitat-specific harvest mortality. Together, the bulk of research on this population shows that harvesting impacts population demography through many different pathways, with some being more subtle than others. These complex pathways influence the demographic variance and affect stochastic processes such as population growth, genetic drift, and rates of evolutionary change, and they must therefore be acknowledged in management plans to achieve sustainable harvesting.
{"title":"Demographic consequences of harvesting: a case study from a small and isolated moose population","authors":"I. Herfindal, A. Lee, S. Hamel, E. Solberg, B. Sæther","doi":"10.3354/CR01650","DOIUrl":"https://doi.org/10.3354/CR01650","url":null,"abstract":"Harvesting can have a substantial impact on population dynamics and individual performance in wild populations. While the direct consequences of harvest on individual survival and population growth rate are often apparent, harvesting can also have indirect and more subtle demographic consequences. Disentangling these consequences, however, requires in-depth knowledge of individual life histories of both females and males in the population. Here, we summarise demographic research on a population where such data exist: the Vega moose population in northern Norway. In this population, vital rates vary considerably among both females and males, and harvesting increases this variation by generating positive covariation between reproductive performance and survival. The skewed age and sex structure, which is typical of many harvested populations, also has demographic consequences: it reduces the ratio of effective to total population size and influences variation in vital rates in males and females. The moose harvest at Vega is structured by age- and sex-specific quotas, but it is not intentionally selective regarding size or other phenotypic characteristics. Still, harvest selection for earlier birth rates and larger calves was apparent, likely due to habitat-performance relationships and habitat-specific harvest mortality. Together, the bulk of research on this population shows that harvesting impacts population demography through many different pathways, with some being more subtle than others. These complex pathways influence the demographic variance and affect stochastic processes such as population growth, genetic drift, and rates of evolutionary change, and they must therefore be acknowledged in management plans to achieve sustainable harvesting.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84573034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. J. Moe, Anders Hobæk, Jonas Persson, B. Skjelbred, J. Løvik
Lake surface temperatures have increased globally in recent decades. Climate change can affect lake biota directly via enhanced water temperatures, shorter ice cover duration and prolonged stratification, and indirectly via changes in species interactions. Changes in the seasonal dynamics of phytoplankton and zooplankton can further affect whole lake ecosystems. However, separating the effects of climate change from the more direct and dominating effects of nutrients is a challenge. Our aim was to explore the ecological effects of climate change while accounting for the effects of re-oligotrophication in Lake Mjøsa, the largest lake in Norway. While restoration measures since the 1970s have resulted in strongly reduced nutrient levels, the surface water temperature has increased by almost 0.4°C decade-1 during the same period. We analysed long-term trends and abrupt changes in environmental and biological time series as well as changes in the seasonal dynamics of individual plankton taxa. The general long-term trends in phenology were diverging for phytoplankton (later peaks) vs. zooplankton (earlier peaks). However, individual taxa of both phytoplankton and zooplankton displayed earlier peaks. Earlier peaks of the phytoplankton group Cryptophyceae can be explained by increased spring temperature or other climate-related changes. Earlier onset of population growth of certain zooplankton species (Limnocalanus macrurus and Holopedium gibberum) can also be explained by climatic change, either directly (earlier temperature increase) or more indirectly (earlier availability of Cryptophyceae as a food source). In the long run, climate-related changes in both phytoplankton and zooplankton phenology may have implications for the fish communities of this lake.
{"title":"Shifted dynamics of plankton communities in a restored lake: exploring the effects of climate change on phenology through four decades","authors":"S. J. Moe, Anders Hobæk, Jonas Persson, B. Skjelbred, J. Løvik","doi":"10.3354/CR01654","DOIUrl":"https://doi.org/10.3354/CR01654","url":null,"abstract":"Lake surface temperatures have increased globally in recent decades. Climate change can affect lake biota directly via enhanced water temperatures, shorter ice cover duration and prolonged stratification, and indirectly via changes in species interactions. Changes in the seasonal dynamics of phytoplankton and zooplankton can further affect whole lake ecosystems. However, separating the effects of climate change from the more direct and dominating effects of nutrients is a challenge. Our aim was to explore the ecological effects of climate change while accounting for the effects of re-oligotrophication in Lake Mjøsa, the largest lake in Norway. While restoration measures since the 1970s have resulted in strongly reduced nutrient levels, the surface water temperature has increased by almost 0.4°C decade-1 during the same period. We analysed long-term trends and abrupt changes in environmental and biological time series as well as changes in the seasonal dynamics of individual plankton taxa. The general long-term trends in phenology were diverging for phytoplankton (later peaks) vs. zooplankton (earlier peaks). However, individual taxa of both phytoplankton and zooplankton displayed earlier peaks. Earlier peaks of the phytoplankton group Cryptophyceae can be explained by increased spring temperature or other climate-related changes. Earlier onset of population growth of certain zooplankton species (Limnocalanus macrurus and Holopedium gibberum) can also be explained by climatic change, either directly (earlier temperature increase) or more indirectly (earlier availability of Cryptophyceae as a food source). In the long run, climate-related changes in both phytoplankton and zooplankton phenology may have implications for the fish communities of this lake.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74746489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Herfindal, S. Aanes, R. Benestad, A. Finstad, A. Salthaug, N. Stenseth, B. Sæther
Environmental variation in time and space affects biological processes such as extinction risk and speed of adaptation to environmental change. The spatial structure of environmental variation may vary among ecosystems, for instance due to differences in the flow of nutrients, genes and individuals. However, inferences about ecosystem spatial scale should also include spatial autocorrelation in environmental stochasticity, such as fluctuations in weather or climate. We used spatially structured time series (19-36 yr) on temperature from 4 different ecosystems (terrestrial, limnic, coastal sea and open ocean) to assess the spatiotemporal patterns of environmental variation over large geographical scales (up to 1900 km) during summer and winter. The distance of positive spatial autocorrelation in mean temperature was greatest for the terrestrial system (range: 592-622 km), and shorter for the open ocean (range: 472-414 km), coastal sea (range: 155-814 km) and the limnic systems (range: 51-324 km), suggesting a stronger spatial structure in environmental variation in the terrestrial system. The terrestrial system had high spatial synchrony in temperature (mean correlation: winter = 0.82, summer = 0.66) with a great spatial scaling (>650 km). Consequently, populations of terrestrial species experience similar environmental fluctuations even at distances up to 1000 km, compared to species in the aquatic systems (<500 km). There were clear seasonal differences in environmental synchrony in the terrestrial and limnic systems, but less so in the other systems. Our results suggest that biological processes affected by environmental stochasticity occur at the largest spatial scale in terrestrial systems, but their magnitude depends on whether the process is affected by winter or summer conditions.
{"title":"Spatiotemporal variation in climatic conditions across ecosystems","authors":"I. Herfindal, S. Aanes, R. Benestad, A. Finstad, A. Salthaug, N. Stenseth, B. Sæther","doi":"10.3354/CR01641","DOIUrl":"https://doi.org/10.3354/CR01641","url":null,"abstract":"Environmental variation in time and space affects biological processes such as extinction risk and speed of adaptation to environmental change. The spatial structure of environmental variation may vary among ecosystems, for instance due to differences in the flow of nutrients, genes and individuals. However, inferences about ecosystem spatial scale should also include spatial autocorrelation in environmental stochasticity, such as fluctuations in weather or climate. We used spatially structured time series (19-36 yr) on temperature from 4 different ecosystems (terrestrial, limnic, coastal sea and open ocean) to assess the spatiotemporal patterns of environmental variation over large geographical scales (up to 1900 km) during summer and winter. The distance of positive spatial autocorrelation in mean temperature was greatest for the terrestrial system (range: 592-622 km), and shorter for the open ocean (range: 472-414 km), coastal sea (range: 155-814 km) and the limnic systems (range: 51-324 km), suggesting a stronger spatial structure in environmental variation in the terrestrial system. The terrestrial system had high spatial synchrony in temperature (mean correlation: winter = 0.82, summer = 0.66) with a great spatial scaling (>650 km). Consequently, populations of terrestrial species experience similar environmental fluctuations even at distances up to 1000 km, compared to species in the aquatic systems (<500 km). There were clear seasonal differences in environmental synchrony in the terrestrial and limnic systems, but less so in the other systems. Our results suggest that biological processes affected by environmental stochasticity occur at the largest spatial scale in terrestrial systems, but their magnitude depends on whether the process is affected by winter or summer conditions.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77236366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ocean–Land Atmosphere Model (OLAM) performance for major extreme meteorological events near the coastal region of southern Brazil","authors":"D. C. Souza, Renato Ramos da Silva","doi":"10.3354/CR01651","DOIUrl":"https://doi.org/10.3354/CR01651","url":null,"abstract":"","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77650279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The agro-pastoral ecotone of Northwestern China (APENC) is one of the major agricultural production areas in China and a region where climate change is evident. Maize is a widely cultivated crop in the APENC, but the potential impact of climate change on maize, and potential adaptation strategies in response to this, are poorly understood. In this study, we used the Cropping System Model (CSM)-CERES-Maize to evaluate the impacts of climate change on maize yield, as well as the feasibility of 2 adaptation strategies; namely, adjusting the planting date and supplying irrigation. CSM-CERES-Maize was driven by an ensemble of 20 global climate models under 2 Representative Concentration Pathways (RCPs: RCP4.5 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). CSM-CERES-Maize performed well in simulating phenology, leaf area index (LAI), maize yield, and soil water dynamics. The results showed that irrigated maize yield would change by +3.9, -16.3, and -20.4% under the RCP4.5 scenario and +0.1, -31.2, and -53.1% under the RCP8.5 scenario in the 2030s, 2060s, and 2090s, respectively. Rainfed maize yield during the 2030s, 2060s, and 2090s would change by +21.7, +16.4, and +12.6% under the RCP4.5 scenario and +25.1, +4.8, and -12.3% under the RCP8.5 scenario, respectively. Evaluation of adaptation strategies suggests that delaying planting dates and supplying irrigation at the tasseling and grain filling stages are the best strategies to increase maize yield under climate change. These results will provide comprehensive information for local policymakers to combat the adverse impacts of climate change.
{"title":"Climate change impacts and adaptation strategies on rainfed and irrigated maize in the agro-pastoral ecotone of Northwestern China","authors":"Z. Han, B. Zhang, G. Hoogenboom, Xia Li, C. He","doi":"10.3354/CR01635","DOIUrl":"https://doi.org/10.3354/CR01635","url":null,"abstract":"The agro-pastoral ecotone of Northwestern China (APENC) is one of the major agricultural production areas in China and a region where climate change is evident. Maize is a widely cultivated crop in the APENC, but the potential impact of climate change on maize, and potential adaptation strategies in response to this, are poorly understood. In this study, we used the Cropping System Model (CSM)-CERES-Maize to evaluate the impacts of climate change on maize yield, as well as the feasibility of 2 adaptation strategies; namely, adjusting the planting date and supplying irrigation. CSM-CERES-Maize was driven by an ensemble of 20 global climate models under 2 Representative Concentration Pathways (RCPs: RCP4.5 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). CSM-CERES-Maize performed well in simulating phenology, leaf area index (LAI), maize yield, and soil water dynamics. The results showed that irrigated maize yield would change by +3.9, -16.3, and -20.4% under the RCP4.5 scenario and +0.1, -31.2, and -53.1% under the RCP8.5 scenario in the 2030s, 2060s, and 2090s, respectively. Rainfed maize yield during the 2030s, 2060s, and 2090s would change by +21.7, +16.4, and +12.6% under the RCP4.5 scenario and +25.1, +4.8, and -12.3% under the RCP8.5 scenario, respectively. Evaluation of adaptation strategies suggests that delaying planting dates and supplying irrigation at the tasseling and grain filling stages are the best strategies to increase maize yield under climate change. These results will provide comprehensive information for local policymakers to combat the adverse impacts of climate change.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84571554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accuracy of different downscaling methods in projecting future precipitation and air temperature from general circulation models (GCMs) has rarely been addressed with regards to the Tibetan Plateau, and this information is important for future water resource management in the region. The performance of automated statistical downscaling (ASD) and Delta downscaling methods in predicting precipitation and air temperature was evaluated at 19 meteorological stations in the Qilian Mountains and Hexi Corridor (QM-HC) by comparing with in situ observations from 2006-2015. These comparisons, based on Representative Concentration Pathway 4.5 (RCP4.5), suggest that the difference in annual precipitation between the ASD model and the Delta method is 17 mm. Testing different weights of the 2 downscaling methods indicates that combining the 2 methods results in lower uncertainty. The downscaling of annual precipitation projected by weighting the results of the 2 methods suggested that, based on RCP4.5, precipitation will not increase significantly from 2021-2100 compared to the past (1961-2005) and will fluctuate steadily in the coming decades. These projections are in contrast with previous projections of a significant increase. Air temperature is projected to increase by approximately 0.2°C decade-1 from 2021-2100 according to the weighted average of the ASD model and Delta method based on RCP4.5. This study indicates that management measures based on projected increased precipitation should be carefully reconsidered in different regions.
{"title":"Impact of Automated Statistical Downscaling and Delta Downscaling methods on projecting future climate change in the northeast Tibetan Plateau","authors":"A. Chen, S. Zhang, Z. Li","doi":"10.3354/CR01634","DOIUrl":"https://doi.org/10.3354/CR01634","url":null,"abstract":"The accuracy of different downscaling methods in projecting future precipitation and air temperature from general circulation models (GCMs) has rarely been addressed with regards to the Tibetan Plateau, and this information is important for future water resource management in the region. The performance of automated statistical downscaling (ASD) and Delta downscaling methods in predicting precipitation and air temperature was evaluated at 19 meteorological stations in the Qilian Mountains and Hexi Corridor (QM-HC) by comparing with in situ observations from 2006-2015. These comparisons, based on Representative Concentration Pathway 4.5 (RCP4.5), suggest that the difference in annual precipitation between the ASD model and the Delta method is 17 mm. Testing different weights of the 2 downscaling methods indicates that combining the 2 methods results in lower uncertainty. The downscaling of annual precipitation projected by weighting the results of the 2 methods suggested that, based on RCP4.5, precipitation will not increase significantly from 2021-2100 compared to the past (1961-2005) and will fluctuate steadily in the coming decades. These projections are in contrast with previous projections of a significant increase. Air temperature is projected to increase by approximately 0.2°C decade-1 from 2021-2100 according to the weighted average of the ASD model and Delta method based on RCP4.5. This study indicates that management measures based on projected increased precipitation should be carefully reconsidered in different regions.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88666563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. L. Cerón, RV Andreoli, M. Kayano, Álvaro Ávila-Díaz
In this article, we propose a novel approach for assessing the effects of sea surface temperature (SST) variations in the eastern Pacific and the Caribbean Sea on the Choco low-level jet (CJ) intensity over the 1900-2015 period that involved defining the interbasin gradient index (IGR) between these 2 oceanic basins. We also studied the effects on rainfall in northwestern South America and Central America in the high CJ season during September-November (SON). Wavelet coherence analysis showed high consistency between CJ and IGR on an interannual scale of 2-8 yr. Precipitation increased over central, western, and northern Colombia and most of Central America during strong CJ (SCJ) and decreased during weak CJ (WCJ) events, which occurred, respectively, in the negative IGR (NIGR) and positive IGR (PIGR) phases. NIGR is associated with anomalous cooling in the tropical Pacific and warming in the equatorial Atlantic; opposite patterns are observed during PIGR. Also, the CJ and the Caribbean low-level jet (CLLJ) showed reversed intensities such that as one strengthened, the other weakened and vice versa. Our results indicate that the low-frequency SST anomalies in the North Atlantic affect the IGR and low-level jet intensities associated with changes in large-scale circulation modulated by the Atlantic multidecadal oscillation (AMO). Indeed, positive precipitation anomalies during the SCJ under NIGR were more accentuated and extensive in the warm AMO (WAMO) than in the cold AMO (CAMO) phase. Conversely, negative precipitation anomalies during WCJ under PIGR were more accentuated and extensive in the CAMO than in the WAMO.
{"title":"Role of the eastern Pacific-Caribbean Sea SST gradient in the Choco low-level jet variations from 1900-2015","authors":"W. L. Cerón, RV Andreoli, M. Kayano, Álvaro Ávila-Díaz","doi":"10.3354/cr01633","DOIUrl":"https://doi.org/10.3354/cr01633","url":null,"abstract":"In this article, we propose a novel approach for assessing the effects of sea surface temperature (SST) variations in the eastern Pacific and the Caribbean Sea on the Choco low-level jet (CJ) intensity over the 1900-2015 period that involved defining the interbasin gradient index (IGR) between these 2 oceanic basins. We also studied the effects on rainfall in northwestern South America and Central America in the high CJ season during September-November (SON). Wavelet coherence analysis showed high consistency between CJ and IGR on an interannual scale of 2-8 yr. Precipitation increased over central, western, and northern Colombia and most of Central America during strong CJ (SCJ) and decreased during weak CJ (WCJ) events, which occurred, respectively, in the negative IGR (NIGR) and positive IGR (PIGR) phases. NIGR is associated with anomalous cooling in the tropical Pacific and warming in the equatorial Atlantic; opposite patterns are observed during PIGR. Also, the CJ and the Caribbean low-level jet (CLLJ) showed reversed intensities such that as one strengthened, the other weakened and vice versa. Our results indicate that the low-frequency SST anomalies in the North Atlantic affect the IGR and low-level jet intensities associated with changes in large-scale circulation modulated by the Atlantic multidecadal oscillation (AMO). Indeed, positive precipitation anomalies during the SCJ under NIGR were more accentuated and extensive in the warm AMO (WAMO) than in the cold AMO (CAMO) phase. Conversely, negative precipitation anomalies during WCJ under PIGR were more accentuated and extensive in the CAMO than in the WAMO.","PeriodicalId":10438,"journal":{"name":"Climate Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88738523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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