共查询到20条相似文献，搜索用时 218 毫秒
1.
This paper explores changes in climatic variables, including solar radiation, rainfall, fraction of diffuse radiation (FDR) and temperature, during wheat season (October to May) and maize season (June to September) from 1961 to 2003 at four sites in the North China Plain (NCP), and then evaluates the effects of these changes on crop growth processes, productivity and water demand by using the Agricultural Production Systems Simulator. A significant decline in radiation and rainfall was detected during the 43 years, while both temperature and FDR exhibit an increasing trend in both wheat and maize seasons. The average trend of each climatic variable for each crop season from the four sites is that radiation decreased by 13.2 and 6.2 MJ m?2 a?1, precipitation decreased by 0.1 and 1.8 mm a?1, minimum temperature increased by 0.05 and 0.02°C a?1, maximum temperature increased by 0.03 and 0.01°C a?1, FDR increased by 0.21 and 0.38% a?1 during wheat and maize season, respectively. Simulated crop water demand and potential yield was significantly decreased because of the declining trend in solar radiation. On average, crop water demand was decreased by 2.3 mm a?1 for wheat and 1.8 mm a?1 for maize if changes in crop variety were not considered. Simulated potential crop yields under fully irrigated condition declined about 45.3 kg ha?1 a?1 for wheat and 51.4 kg ha?1 a?1 for maize at the northern sites, Beijing and Tianjin. They had no significant changes in the southern sites, Jinan and Zhengzhou. Irrigation, fertilization development and crop variety improvement are main factors to contribute to the increase in actual crop yield for the wheat–maize double cropping system, contrasted to the decline in the potential crop yield. Further research on how the improvement in crop varieties and management practices can counteract the impact of climatic change may provide insight into the future sustainability of wheat–maize double crop rotations in the NCP. 相似文献
2.
Wheat is the second important cereal crop after rice in West Bengal. During last three decades, due to climate fluctuations and variability, the productivity of this crop remains almost constant, bringing the threat of food security of this State. The objectives of the present study were to assess the trend of climatic variables (rainfall, rainy days, and temperature) over six locations covering five major agro-climatic sub-zones of West Bengal and to estimate the variability of potential, simulated yield using crop simulation model (DSAATv4.5) and the yield gap with actual yield. There were no significant change of rainfall and rainy days in annual, seasonal and monthly scale at all the study sites. In general, the maximum temperature is decreasing throughout West Bengal. Except for Birbhum, the minimum temperature increased significantly in different study sites. District average yield of wheat varied from 1757 kg ha?1 at Jalpaiguri to 2421 kg ha?1at Birbhum. The actual yield trend ranged from ??4.7 kg ha?1 year?1 at Nadia to 32.8 kg ha?1 year?1 at Birbhum. Decreasing trend of potential yield was observed in Terai (Jalpaiguri), New Alluvial Zone (Nadia) and Coastal saline zone (South 24 Parganas), which is alarming for food security in West Bengal. 相似文献
3.
Changes of erosive rainfall for El Niño and La Niña years in the northern Andean highlands of Peru 总被引：1，自引：0，他引：1
Information related to rainfall erosivity in the Andes is scarce. This study was carried out to determine the characteristics of rainfall events at the La Encañada watershed, northern Peru, using daily rainfall data from the 1995 to 2000 period that included all the El Niño and Southern Oscillation (ENSO) phases. Three weather stations were installed within the study area, at the top, middle and bottom of the watershed. We analysed the total amount, duration, intensity, kinetic energy and probability of return of rainfall events. In general, 80% of the rainfall events at watershed level had an average rainfall intensity lower than 2.5 mm h?1 and only 4% had an average intensity larger than 7.5 mm h?1. Rainfall erosivity registered at the bottom of the watershed was slightly higher than in the rest of the area. The highest intensities were observed during an El Niño year whereas a La Niña year was characterized by the highest amount of total rainfall compared to the other ENSO phases and by the low intensity rain events. Simulations using the WEPP model estimated higher sediment yield and runoff for the bottom of the watershed during a La Niña year versus El Niño or Neutral years. Even when the analysed rainfall data was too limited to conclude erosion and runoff during any ENSO phase, the simulated results showed us the trend of the behaviour of rainfall erosivity under the ENSO phases at different locations. 相似文献
4.
ENSO teleconnections imply anomalous weather conditions, causing yield shortages, price fluctuations, and civil unrest. We estimate ENSO’s effect on U.S. county-level corn yield distributions and find that temperature and precipitation alone are not sufficient to summarize the effect of global climate on agriculture. We find that acreage-weighted aggregate impacts mask considerable spatial heterogeneity at the county-level for the mean, variance, and downside risk of corn yields. Impacts for mean yields range from ??24 to 33 % for El Niño and ??25 to 36 % for La Niña, with the geographical center of losses shifting from the Eastern to Western corn belt. ENSO’s effect on the variance of crop yields is highly localized and is not representative of a variance-preserving shift. We also find that downside risk impacts are large and spatially correlated across counties. 相似文献
5.
The impacts of climate change on water and nitrogen cycles in arid central Arizona (USA) were investigated by integrating the Second Generation Coupled Global Climate Model (CGCM2) and a widely used, physical process-based model, Soil and Water Assessment Tool (SWAT). With statistically downscaled daily climate data from the CGCM2 as model input, SWAT predicted increased potential evapotranspiration and decreased surface runoff, lateral flow, soil water, and groundwater recharge, which suggests serious consequences for the water cycle in this desert catchment in the future. Specifically, stream discharge is projected to decrease by 31 % in the 2020s, 47 % in the 2050s, and 56 % in the 2080s compared to the mean discharge for the base period (0.73 m3/s). A flow-duration analysis reveals that the projected reduction of stream discharge in the future is attributable to significant decreases in mid-range and low-flow conditions; however, flood peaks would show a slight increase in the future. The drier and hotter future also will decrease the rate of nitrogen mineralization in the catchment and ultimately, nitrate export from the stream. Since mean mineralization rate would decrease by 15 % in the 2020s, 28 % in the 2050s, and 35 % in the 2080s compared to the based period (9.3 g N ha?1 d?1), the combined impact of reduced catchment mineralization and reduced streamflow would predict declining nitrate export: from today’s mean value of 30 kg N/d, to 20, 15 and 12 kg N/d by the 2020s, 2050s, and 2080s, respectively. 相似文献
6.
The relationship between the El Niño Southern Oscillation (ENSO) and the Southern Hemisphere Annular Mode (SAM) is examined, with the goal of understanding how various strong SAM events modulate the ENSO teleconnection to the South Pacific (45°–70°S, 150°–70°W). The focus is on multi-month, multi-event variations during the last 50 years. A significant (p < 0.10) relationship is observed, most marked during the austral summer and in the 1970s and 1990s. In most cases, the significant relationship is brought about by La Niña (El Niño) events occurring with positive (negative) phases of the SAM more often than expected by chance. The South Pacific teleconnection magnitude is found to be strongly dependent on the SAM phase. Only when ENSO events occur with a weak SAM or when a La Niña (El Niño) occurs with a positive (negative) SAM phase are significant South Pacific teleconnections found. This modulation in the South Pacific ENSO teleconnection is directly tied to the interaction of the anomalous ENSO and SAM transient eddy momentum fluxes. During La Niña/SAM+ and El Niño/SAM? combinations, the anomalous transient momentum fluxes in the Pacific act to reinforce the circulation anomalies in the midlatitudes, altering the circulation in such a way to maintain the ENSO teleconnections. In La Niña/SAM? and El Niño/SAM+ cases, the anomalous transient eddies oppose each other in the midlatitudes, overall acting to reduce the magnitude of the high latitude ENSO teleconnection. 相似文献
7.
Through an oceanic mixed-layer heat budget analysis, the dominant processes contributing to the largest decay rate (− 0.37 °C/mon) in EP El Nino, the moderate delay rate (− 0.22 °C/mon) in CP El Nino and the smallest decay rate (0.13 °C/mon) in La Nina, are identified. The result shows that both dynamic (wind induced equatorial ocean waves and thermocline changes) and thermodynamic (net surface solar radiation and latent heat flux changes) processes contribute to a fast decay and thus phase transition in EP El Niño composite, whereas the thermodynamic process has less effect on the decay rate for both CP El Niño and La Niña due to the westward shift of sea surface temperature anomaly (SSTA) centers. Thus, the difference in surface wind stress forcing is critical in contributing to evolution asymmetry between CP El Niño and La Niña, while the difference in both the wind stress and heat flux anomalies contribute to evolution asymmetry between EP El Niño and La Niña. It is interesting to note that El Nino induced anomalous anticyclone over the western North Pacific is stronger and shifts more toward the east during EP El Niño than during CP El Niño, while compared to CP El Niño, the center of an anomalous cyclone during La Niña shifts further to the west. As a consequence, both EP and CP El Niño decay fast and transform into a La Niña episode in the subsequent year, whereas La Niña has a much slower decay rate and re-develops in the second year.
相似文献8.
Christine K. Lee Samuel S. P. Shen Barbara Bailey Gerald R. North 《Theoretical and Applied Climatology》2009,97(1-2):195-203
Maximum likelihood factor analysis (MLFA) is applied to investigate the variables of monthly Tropical Pacific sea surface temperatures (SST) from Niño 1+2, Niño 3, Niño 3.4, and Niño 4 and precipitation over New South Wales and Queensland of eastern Australia, Kalimantan Island of Indonesia, and California and Oregon of the west coast of the United States. The monthly data used were from 1950 to 1999. The November-February SST with time leads of 0, 1, 2, and 3 months to precipitation are considered for both El Niño warm phases and non El Niño seasons. Interpretations of the factor loadings are made to diagnose relationships between the SST and precipitation variables. For El Niño signals, the rotated FA loadings can efficiently group the SST and precipitation variables with interpretable physical meanings. When the time lag is 0 or 1 month, the November–February El Niño SST explains much of the drought signals over eastern Australia and Kalimantan. However, when the time lag is 2 or 3 months, the same SST cannot adequately explain the precipitation during January–May over the two regions. Communality results of five factors for precipitation indicate nearly 100% explanation of variances for Queensland and California, but the percentages are reduced to only about 30% for Oregon and Kalimantan. Factor scores clearly identify the strongest El Niño relevant to precipitation variations. Principal component factor analysis (PCFA) is also investigated, and its results are compared with MLFA. The comparison indicates that MLFA can better group SST data relevant to precipitation. The residuals of MLFA are always smaller than the PCFA. Thus, MLFA may become a useful tool for improving potential predictability of precipitation from SST predictors. 相似文献
9.
Using the output of 12 models from the Paleoclimate Modeling Intercomparison Project Phase 3, we investigate the feedback process responsible for changes in El Niño-Southern Oscillation activity during the mid-Holocene based on a linear stability index (Bjerknes stability index; BJ index) analysis. The multi-model ensemble mean (MME) variance of the Niño-3.4 index (sea surface temperature anomalies averaged over 5°S–5°N, 170°–120°W) simulated for 6000 years ago (6 kya) was 13% lower than that for the pre-industrial era (0 kya), while changes in the MME BJ index were negligible. This is due to a balance between enhanced damping by anomalous thermal advection by mean currents (MA) and enhanced positive thermocline feedback (TH). Seven of the models show that MME variance of the Niño-3.4 and BJ indexes for the 6 kya run is 21 and 70% lower, respectively, than the 0 kya run. However, two models show the opposite change. Interestingly, MA in both model groups increases, especially due to the mean meridional current associated with enhanced trade winds, indicating a robust mechanism. The opposite tendency between the two groups is mainly due to large TH in the second group 6 kya, as a result of enhanced air-sea coupling and strongly reduced ocean stratification due to subsurface warming, which led to increased sensitivity of the zonal thermocline contrast to surface zonal wind stress. 相似文献
10.
Previous studies suggested that the wintertime SST in the North Pacific that are generated by the concurrent North Pacific Oscillation (NPO) are able to force El Niño during subsequent winter via the so-called ‘seasonal footprinting mechanism’ (SFM). We examine how the NPO effectively generates the El Niño via the SFM in the observations and models. The occurrence ratio for El Niño under conditions of NPO forcing during the previous winters is about 41 % for the period of 61 years (1949–2009), indicating that the atmospheric forcing from the mid-latitudes through the SFM does not always trigger an El Niño. We observed certain favorable conditions under which the SFM may effectively induce El Niño. We directly compared these observations with two cases: when the wintertime NPO leads to El Niño during the following winter through the SFM, and when the wintertime NPO is not followed by El Niño. Our analysis demonstrates that the spatial structures of the NPO, associated wind speed and net heat flux in the northeast Pacific, differ between the two cases. Such differences determine the existence of a footprint SST in the northeastern Pacific during the late spring and summer, which plays a key role in initiating the El Niño via the projection of westerly wind stress anomalies onto the equatorial Pacific during the same seasons. By conducting linear baroclinic model experiments, it is found that the positions of La Niña SST forcing during the previous winter are able to modify the spatial structures of the NPO, which produces favorable conditions for the El Niño during subsequent winter via the SFM. 相似文献
11.
Abel Antônio Silva Mariza Pereira de Souza Echer 《Meteorology and Atmospheric Physics》2013,120(3-4):201-212
Clouds are believed to reflect temporal climate changes through variations in their amounts, characteristics, and occurrence. In addition, they reflect both weather and climate in a region. In this work, a methodology to determine the local cloud cover (LCC) is proposed using sky images obtained from a ground-based instrument. Three years of sky images from an urban, tropical site were obtained and analyzed through that methodology. Monthly average LCC varied from 3 to 96 %, while seasonal average values were 68 % for summer, 54 % for spring, 46 % for fall, and 23 % for winter. LCC results show a clear seasonal dependence and a fair agreement (r 2 = 0.72) with satellite data, which typically underestimate the cloud cover in relation to LCC. Our analysis also suggests the possibility of a measurable link between LCC and natural events like the El Niño Southern Oscillation. 相似文献
12.
Downscaling over Vietnam using the stretched-grid CCAM: verification of the mean and interannual variability of rainfall 总被引：1，自引：1，他引：0
Rainfall over Vietnam is highly variable from north to south, due to the interaction of the monsoonal winds with the terrain. There is high rainfall from April to September, and little rainfall from October to March (except along the central Vietnam coast). In order to study the ability of the Commonwealth Scientific and Industrial Research Organisation stretched-grid Conformal Cubic Atmospheric Model (CCAM) to capture the climatic and interannual variability of rainfall, downscaled simulations at approximately 20 km horizontal resolution over the region were produced for the period 1979–2001. A scale-selective digital filter was used to force the winds, temperature and sea-level pressure from the ERA-Interim reanalysis for length scales greater than about 700 km. For wind and temperature, the forcing is applied for pressure-sigma levels above about 0.9. ERA-Interim sea surface temperatures were used over the oceans. The simulations were primarily validated against the gridded Asian Precipitation Highly Resolved Observational Data Integration Toward Evaluation of the Water Resources rainfall dataset and station observations using standard statistical methods. It was found that CCAM reproduces well the amount and spatial variability of rainfall, with an area-averaged bias for the entire study domain of less than 1 mm day?1; CCAM is also able to capture the rainfall pattern under different El Niño Southern Oscillation phases reasonably well for the dry season. For interannual variability, the simulation generally performed better for North and Central Vietnam than for South Vietnam, where rainfall variability was overestimated. 相似文献
13.
The influence of El Nio-Southern Oscillation (ENSO) on the convectively coupled Kelvin waves over the tropical Pacific is investigated by comparing the Kelvin wave activity in the eastern Pacific (EP) El Nio, central Pacific (CP) El Nio, and La Nia years, respectively, to 30-yr (1982-2011) mean statistics. The convectively coupled Kelvin waves in this study are represented by the two leading modes of empirical orthogonal function (EOF) of 2-25-day band-pass filtered daily outgoing longwave radiation (OLR), with the estimated zonal wavenumber of 3 or 4, period of 8 days, and eastward propagating speed of 17 ms-1 . The most significant impact of ENSO on the Kelvin wave activity is the intensification of the Kelvin waves during the EP El Nios. The impact of La Nia on the reduction of the Kelvin wave intensity is relatively weaker, reflecting the nonlinearity of tropical deep convection and the associated Kelvin waves in response to ENSO sea surface temperature (SST) anomalies. The impact of the CP El Nio on the Kelvin waves is less significant due to relatively weaker SST anomalies and smaller spatial coverage. ENSO may also alter the frequency, wavelength, and phase speed of the Kelvin waves. This study demonstrates that low-frequency ENSO SST anomalies modulate high-frequency tropical disturbances, an example of weather-climate linkage. 相似文献
14.
Changes in wintertime 10 m winds due to the El Niño-Southern Oscillation are examined using a 6 km resolution climate simulation of Southern California covering the period from 1959 through 2001. Wind speed statistics based on regional averages reveal a general signal of increased mean wind speeds and wind speed variability during El Niño across the region. An opposite and nearly as strong signal of decreased wind speed variability during La Niña is also found. These signals are generally more significant than the better-known signals in precipitation. In spite of these regional-scale generalizations, there are significant sub-regional mesoscale structures in the wind speed impacts. In some cases, impacts on mean winds and wind variability at the sub-regional scale are opposite to those of the region as a whole. All of these signals can be interpreted in terms of shifts in occurrences of the region’s main wind regimes due to the El Niño phenomenon. The results of this study can be used to understand how interannual wind speed variations in regions of Southern California are influenced by the El Niño phenomenon. 相似文献
15.
A significant negative correlation between the total rainfall averaged over South Korea and the Niño-3.4 index was found for the month of September. To find out the reason for this negative correlation, composite analyses were carried out for the highest and lowest 8 years of the Niño-3.4 index. During the strong El Niño year, an anomalous anticyclone occurs in the continental East Asia, while an anomalous cyclone emerges in the subtropical western Pacific. The resultant eastward pressure gradient force induces anomalous northerlies in most regions of East Asia, which produces anomalous cold and dry conditions throughout the troposphere between 120° and 140°E, reducing the Korean rainfall. It is also found that during El Niño year, tropical cyclones (TCs) tend to recurve far east offshore of Japan because the weakening of the western North Pacific subtropical high (WNPSH). During La Niña years, on the other hand, the strengthening and westward extension of the WNPSH render more TCs influencing the Korean peninsula. Therefore, the TC track changes associated with El Niño-Southern Oscillation is another contributor to change of the Korean rainfall. 相似文献
16.
Characterizing spatial and temporal variability of crop yield caused by climate and irrigation in the North China Plain 总被引：1，自引：0，他引：1
Chao Chen Walter E. Baethgen Enli Wang Qiang Yu 《Theoretical and Applied Climatology》2011,106(3-4):365-381
Grain yields of wheat and maize were obtained from national statistics and simulated with an agricultural system model to investigate the effects of historical climate variability and irrigation on crop yield in the North China Plain (NCP). Both observed and simulated yields showed large temporal and spatial variability due to variations in climate and irrigation supply. Wheat yield under full irrigation (FI) was 8?t?ha?1 or higher in 80% of seasons in the north, it ranged from 7 to 10?t?ha?1 in 90% of seasons in central NCP, and less than 9?t?ha?1 in 85% of seasons in the south. Reduced irrigation resulted in increased crop yield variability. Wheat yield under supplemental irrigation, i.e., to meet only 50% of irrigation water requirement [supplemental irrigation (SI)] ranged from 2.7 to 8.8?t?ha?1 with the maximum frequency of seasons having the range of 4?C6?t?ha?1 in the north, 4?C7?t?ha?1 in central NCP, and 5?C8?t?ha?1 in the south. Wheat yield under no irrigation (NI) was lower than 1?t?ha?1 in about 50% of seasons. Considering the NCP as a whole, simulated maize yield under FI ranged from 3.9 to 11.8?t?ha?1 with similar frequency distribution in the range of 6?C11.8?t?ha?1 with the interval of 2?t?ha?1. It ranged from 0 to 11.8?t?ha?1, uniformly distributed into the range of 4?C10?t?ha?1 under SI, and NI. The results give an insight into the levels of regional crop production affected by climate and water management strategies. 相似文献
17.
Hengyi Weng Guoxiong Wu Yimin Liu Swadhin K. Behera Toshio Yamagata 《Climate Dynamics》2011,36(3-4):769-782
Possible influences of three coupled ocean–atmosphere phenomena in the Indo-Pacific Oceans, El Niño, El Niño Modoki and the Indian Ocean Dipole (IOD), on summer climate in China are studied based on data analysis for the summers of 1951–2007. Partial correlation/regression analysis is used to find the influence paths through the related anomalous mid- and low-level tropospheric circulations over the oceanic region and East Eurasia, including the western North Pacific summer monsoon (WNPSM). Among the three phenomena, El Niño Modoki has the strongest relationship with the WNPSM. When two or three phenomena coexist with either positive or negative phase, the influences exerted by one phenomenon on summer climate in different regions of China may be enhanced or weakened by other phenomena. In 1994 when both El Niño Modoki and IOD are prominent without El Niño, a strong WNPSM is associated with severe flooding in southern China and severe drought in the Yangtze River Valley (YRV). The 500 hPa high systems over China are responsible for heat waves in most parts of China. In 1983 when a strong negative phase of El Niño Modoki is accompanied by moderate El Niño and IOD, a weak WNPSM is associated with severe flooding in the YRV and severe drought in southern China. The 500 hPa low systems over China are responsible for the cold summer in the YRV and northeastern China. For rainfall, the influence path seems largely through the low-level tropospheric circulations including the WNPSM. For temperature, the influence path seems largely through the mid-level tropospheric circulations over East Eurasia/western North Pacific Ocean. 相似文献
18.
Bryan C. Weare 《Climate Dynamics》2013,41(7-8):2165-2177
Teleconnections associated with warm El Niño/southern oscillation (ENSO) events in 20 climate model intercomparison project 5 (CMIP5) models have been compared with reanalysis observations. Focus has been placed on compact time and space indices, which can be assigned a specific statistical confidence. Nearly all of the models have surface temperature, precipitation and 250 hPa geopotential height departures in the Tropics that are in good agreement with the observations. Most of the models also have realistic anomalies of Northern Hemisphere near-surface temperature, precipitation and 500 hPa geopotential height. Model skill for these variables is significantly related to the ability of a model to accurately simulate Tropical 250 hPa height departures. Additionally, most models have realistic temperature and precipitation anomalies over North America, which are linked to a model’s ability to simulate Tropical 250 hPa and Northern Hemisphere 500 hPa height departures. The skills of temperature and precipitation departures over the Northern Hemisphere and North America are associated with the ability to realistically simulate realistic ENSO frequency and length. Neither horizontal nor vertical resolution differences for either the model atmosphere or ocean are significantly related at the 95 % level to variations in El Niño simulation quality. Overall, recent versions of earlier models have improved in their ability to simulate El Niño teleconnections. For instance, the average model skills of temperature and precipitation for the Tropics, Northern Hemisphere and North America for 11 CMIP5 models are all larger than those for prior versions. 相似文献
19.
Ning Zeng Anthony W. King Ben Zaitchik Stan D. Wullschleger Jay Gregg Shaoqiang Wang Dan Kirk-Davidoff 《Climatic change》2013,118(2):245-257
A carbon sequestration strategy has recently been proposed in which a forest is actively managed, and a fraction of the wood is selectively harvested and stored to prevent decomposition. The forest serves as a ‘carbon scrubber’ or ‘carbon remover’ that provides continuous sequestration (negative emissions). Earlier estimates of the theoretical potential of wood harvest and storage (WHS) based on coarse wood production rates were 10?±?5 GtC y?1. Starting from this physical limit, here we apply a number of practical constraints: (1) land not available due to agriculture; (2) forest set aside as protected areas, assuming 50 % in the tropics and 20 % in temperate and boreal forests; (3) forests difficult to access due to steep terrain; (4) wood use for other purposes such as timber and paper. This ‘top-down’ approach yields a WHS potential 2.8 GtC y?1. Alternatively, a ‘bottom-up’ approach, assuming more efficient wood use without increasing harvest, finds 0.1–0.5 GtC y?1 available for carbon sequestration. We suggest a range of 1–3 GtC y?1 carbon sequestration potential if major effort is made to expand managed forests and/or to increase harvest intensity. The implementation of such a scheme at our estimated lower value of 1 GtC y?1 would imply a doubling of the current world wood harvest rate. This can be achieved by harvesting wood at a moderate harvesting intensity of 1.2 tC ha?1 y?1, over a forest area of 8 Mkm2 (800 Mha). To achieve the higher value of 3 GtC y?1, forests need to be managed this way on half of the world’s forested land, or on a smaller area but with higher harvest intensity. We recommend WHS be considered part of the portfolio of climate mitigation and adaptation options that needs further research. 相似文献
20.
The Puelo River is a watershed shared between Chile and Argentina with a mean annual streamflow of 644 m3 s?1. It has a high ecologic and economic importance, including introduced farmed salmon, tourism, sports fishing and projected hydroelectricity. Using Austrocedrus chilensis and Pilgerodendron uviferum tree-ring records we reconstructed summer–fall (December–May) Puelo River streamflow, which is the first of such reconstructions developed in the Pacific domain of South America. The reconstruction goes back to 1599 and has an adjusted r 2 of 0.42. Spectral analysis of the reconstructed streamflow shows a dominant 84-year cycle which explains 25.1% of the total temporal variability. The Puelo River summer–fall streamflow shows a significant correlation (P?>?0.95, 1943–2002) with hydrological records throughout a vast geographic range within the Valdivian eco-region (35 to 46°S). Seasonal Puelo River interannual streamflow variability is related to large-scale oceanic and atmospheric circulation features. Summer–fall streamflows showed a significant negative correlation with the Antarctic Oscillation (AAO), whereas winter–spring anomalies appear to be positively connected with sea surface temperature variations in the tropical Pacific. In general, above- and below-average discharges in winter–spring are related to El Niño and La Niña events, respectively. The temporal patterns of the observed and reconstructed records of the Puelo River streamflow show a general decreasing trend in the 1943–1999 period. Projected circulation changes for the next decades in the Southern Hemisphere would decrease summer–fall Puelo River streamflows with significant impacts on salmon production, tourism and hydropower generation. 相似文献