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1.
Phenological changes in crops affect efficient agricultural production and can be used as important biological indicators of local and regional climate change. Although crop phenological changes and their responses to climate change, especially temperature, have been investigated, the impact of agronomic practice such as cultivar shifts and planted date changes on crop phenology remains unclear. Here, we used a long-term dataset (1981–2010) of wheat phenology and associated local weather data from 48 agro-meteorological stations in four temperature zones in China to analyze phenological changes of spring and winter wheat. Trend analysis method was used to estimate changes in the date of growth stages and the duration of growth phases, while sensitivity analysis method was used to qualify the response of growth phase duration to mean temperature (Tmean), total precipitation (PRE), and total sunshine duration (SSD). Using the Crop Environment Resource Synthesis-wheat model, we isolated the impacts of climate change, cultivar selection, and sowing date on phenological change of wheat. Results show that phenological changes were greatest in the warm-temperate zone. Sensitivity analysis indicates that growth phase duration was generally negatively related to Tmean and positively related to PRE and SSD. The positive sensitivity response to Tmean occurred in the tillering to jointing and sowing to maturity growth periods in the warmer temperature zones, suggesting that warmer temperatures during the overwintering period hampered effective vernalization in winter wheat. Modeling results further indicate that reductions in wheat growth duration caused by climate change could be offset by the introduction of new cultivars with high thermal requirements and accelerated with delayed sowing date.  相似文献   

2.
A gap between the potential and practical realisation of adaptation exists: adaptation strategies need to be both climate-informed and locally relevant to be viable. Place-based approaches study local and contemporary dynamics of the agricultural system, whereas climate impact modelling simulates climate-crop interactions across temporal and spatial scales. Crop-climate modelling and place-based research on adaptation were strategically reviewed and analysed to identify areas of commonality, differences, and potential learning opportunities to enhance the relevance of both disciplines through interdisciplinary approaches. Crop-modelling studies have projected a 7–15% mean yield change with adaptation compared to a non-adaptation baseline (Nature Climate Change 4:1–5, 2014). Of the 17 types of adaptation strategy identified in this study as place-based adaptations occurring within Central America, only five were represented in crop-climate modelling literature, and these were as follows: fertiliser, irrigation, change in planting date, change in cultivar and area cultivated. The breath and agency of real-life adaptation compared to its representation in modelling studies is a source of error in climate impact simulations. Conversely, adaptation research that omits assessment of future climate variability and impact does not enable to provide sustainable adaptation strategies to local communities so risk maladaptation. Integrated and participatory methods can identify and reduce these sources of uncertainty, for example, stakeholder’s engagement can identify locally relevant adaptation pathways. We propose a research agenda that uses methodological approaches from both the modelling and place-based approaches to work towards climate-informed locally relevant adaptation.  相似文献   

3.
A widely used method of evaluating effects of climate change on flow regime is to perturb the climate inputs to a rainfall–runoff model and examine the effect on a statistic of the modelled flows. Such studies require four elements: a method of perturbing the climate, a rainfall–runoff model, a study catchment and a flow index. In practice the direction and magnitude of the estimated effects depend on each of the four elements, leading to concern over the usefulness and generality of the results. To investigate these uncertainties two climate scenarios and eight climate sensitivity tests have been applied to three UK catchments using two conceptual rainfall–runoff models in order to quantify effects of climate change on three flow indices representing mean runoff, flood magnitudes and low flows. The sensitivity tests were found to be useful to assess the suitability of the models to simulate flows outside the conditions experienced in their calibration. Both models gave internally consistent results but, on close examination, one model was found inappropriate for this application. Results show that the effect of climate change on flow varies between catchments and that different flow response indices can change in opposite directions, e.g. floods increased in magnitude while low flows reduced. Contrasting results were obtained from the two climate scenarios.  相似文献   

4.
Sensitivities to the potential impact of Climate Change on the water resources of the Athabasca River Basin (ARB) and Fraser River Basin (FRB) were investigated. The Special Report on Emissions Scenarios (SRES) of IPCC projected by seven general circulation models (GCM), namely, Japan’s CCSRNIES, Canada’s CGCM2, Australia’s CSIROMk2b, Germany’s ECHAM4, the USA’s GFDLR30, the UK’s HadCM3, and the USA’s NCARPCM, driven under four SRES climate scenarios (A1FI, A2, B1, and B2) over three 30-year time periods (2010–2039, 2040–2069, 2070–2100) were used in these studies. The change fields over these three 30-year time periods are assessed with respect to the 1961–1990, 30-year climate normal and based on the 1961–1990 European Community Mid-Weather Forecast (ECMWF) re-analysis data (ERA-40), which were adjusted with respect to the higher resolution GEM forecast archive of Environment Canada, and used to drive the Modified ISBA (MISBA) of Kerkhoven and Gan (Adv Water Resour 29(6):808–826, 2006). In the ARB, the shortened snowfall season and increased sublimation together lead to a decline in the spring snowpack, and mean annual flows are expected to decline with the runoff coefficient dropping by about 8% per °C rise in temperature. Although the wettest scenarios predict mild increases in annual runoff in the first half of the century, all GCM and emission combinations predict large declines by the end of the twenty-first century with an average change in the annual runoff, mean maximum annual flow and mean minimum annual flow of −21%, −4.4%, and −41%, respectively. The climate scenarios in the FRB present a less clear picture of streamflows in the twenty-first century. All 18 GCM projections suggest mean annual flows in the FRB should change by ±10% with eight projections suggesting increases and 10 projecting decreases in the mean annual flow. This stark contrast with the ARB results is due to the FRB’s much milder climate. Therefore under SRES scenarios, much of the FRB is projected to become warmer than 0°C for most of the calendar year, resulting in a decline in FRB’s characteristic snow fed annual hydrograph response, which also results in a large decline in the average maximum flow rate. Generalized equations relating mean annual runoff, mean annual minimum flows, and mean annual maximum flows to changes in rainfall, snowfall, winter temperature, and summer temperature show that flow rates in both basins are more sensitive to changes in winter than summer temperature.  相似文献   

5.
The study compares two formulas for calculating the daily evapotranspiration ET0 for a reference crop. The first formula was proposed by Allen et al. (AL), while the second one was proposed by Katerji and Perrier with the addition of the carbon dioxide (CO2) effect on evapotranspiration (KP). The study analyses the impact of the calculation by the two formulas on the irrigation requirement (IR). Both formulas are based on the Penman-Monteith equation but adopt different approaches for parameterising the canopy resistance r c . In the AL formula, r c is assumed constant and not sensitive to climate change, whereas in the KP formula, r c is first parameterised as a function of climatic variables, then ET0 is corrected for the air CO2 concentration. The two formulas were compared in two periods. The first period involves data from two sites in the Mediterranean region within a measured climate change period (1981–2006) when all the input climatic variables were measured. The second period (2070–2100) involves data from a future climate change period at one site when the input climatic variables were forecasted for two future climate scenarios (A2 and B2). The annual cumulated values of ET0 calculated by the AL formula are systematically lower than those determined by the KP formula. The differences between the ET0 estimation with the AL and KP formulas have a strong impact on the determination of the IR for the reference crop. In fact, for the two periods, the annual values of IR when ET0 is calculated by the AL formula are systematically lower than those calculated by the KP formula. For the actual measured climate change period, this reduction varied from 26 to 28 %, while for the future climate change period, it varied based on the scenario from 16 % (A2) to 20 % (B2).  相似文献   

6.
Climate change due to a doubling of the carbon dioxide in the atmosphere and its possible impacts on the hydrological cycle are a matter of growing concern. Hydrologists are specifically interested in an assessment of the impacts on the occurrence and magnitude of runoff, evapotranspiration, and soil moisture and their temporal and spatial redistribution. Such impacts become all the more important as they may also affect the water availability in the storage reservoirs. This paper examines the regional effects of climate change on various components of the hydrologic cycle viz., surface runoff, soil moisture, and evapotranspiration for three drainage basins of central India. Plausible hypothetical scenarios of precipitation and temperature changes are used as input in a conceptual rainfall-runoff model. The influences of climate change on flood, drought, and agriculture are highlighted. The response of hypothetical reservoirs in these drainage basins to climate variations has also been studied. Results indicate that the basin located in a comparatively drier region is more sensitive to climatic changes. The high probability of a significant effect of climate change on reservoir storage, especially for drier scenarios, necessitates the need of a further, more critical analysis of these effects.  相似文献   

7.
We identify and remove the main natural perturbations (e.g. volcanic activity, ENSOs) from the global mean lower tropospheric temperatures (T LT ) over January 1979 - June 2017 to estimate the underlying, potentially human-forced trend. The unaltered value is +0.155 K dec?1 while the adjusted trend is +0.096 K dec?1, related primarily to the removal of volcanic cooling in the early part of the record. This is essentially the same value we determined in 1994 (+0.09 K dec?1, Christy and McNider, 1994) using only 15 years of data. If the warming rate of +0.096 K dec?1 represents the net T LT response to increasing greenhouse radiative forcings, this implies that the T LT tropospheric transient climate response (ΔT LT at the time CO2 doubles) is +1.10 ± 0.26 K which is about half of the average of the IPCC AR5 climate models of 2.31 ± 0.20 K. Assuming that the net remaining unknown internal and external natural forcing over this period is near zero, the mismatch since 1979 between observations and CMIP-5 model values suggests that excessive sensitivity to enhanced radiative forcing in the models can be appreciable. The tropical region is mainly responsible for this discrepancy suggesting processes that are the likely sources of the extra sensitivity are (a) the parameterized hydrology of the deep atmosphere, (b) the parameterized heat-partitioning at the oceanatmosphere interface and/or (c) unknown natural variations.  相似文献   

8.
The potential hydrologic impact of climatic change on three sub-basins of the South Saskatchewan River Basin (SSRB) within Alberta, namely, Oldman, Bow and Red Deer River basins was investigated using the Modified Interactions Soil-Biosphere-Atmosphere (MISBA) land surface scheme of Kerkhoven and Gan (Advances in Water Resources 29:808–826 2006). The European Centre for Mid-range Weather Forecasts global re-analysis (ERA-40) climate data, Digital Elevation Model of the National Water Research Institute, land cover data and a priori soil parameters from the Ecoclimap global data set were used to drive MISBA to simulate the runoff of SSRB. Four SRES scenarios (A21, A1FI, B21 and B11) of four General Circulation Models (CCSRNIES, CGCM2, ECHAM4 and HadCM3) of IPCC were used to adjust climate data of the 1961–1990 base period (climate normal) to study the effect of climate change on SSRB over three 30-year time periods (2010–2039, 2040–2069, 2070–2099). The model results of MISBA forced under various climate change projections of the four GCMs with respect to the 1961–1990 normal show that SSRB is expected to experience a decrease in future streamflow and snow water equivalent, and an earlier onset of spring runoff despite of projected increasing trends in precipitation over the 21st century. Apparently the projected increase in evaporation loss due to a warmer climate over the 21st century will offset the projected precipitation increase, leading to an overall decreasing trend in the basin runoff of SSRB. Finally, a Gamma probability distribution function was fitted to the mean annual maximum flow and mean annual mean flow data simulated for the Oldman, Bow and Red Deer River Basins by MISBA to statistically quantify the possible range of uncertainties associated with SRES climate scenarios projected by the four GCMs selected for this study.  相似文献   

9.
Daily rainfall and temperature data were extracted from the multi-ensemble HadRM3H regional climate model (RCM) integrations for control (1960–1990) and future (2070–2100) time-slices. This dynamically downscaled output was bias-corrected on observed mean statistics and used as input to hydrological models calibrated for eight catchments which are critical water resources in northwest England. Simulated daily flow distributions matched observed from Q95 to Q5, suggesting that RCM data can be used with some confidence to examine future changes in flow regime. Under the SRES A2 (UKCIP02 Medium-High) scenario, annual runoff is projected to increase slightly at high elevation catchments, but reduce by ~16% at lower elevations. Impacts on monthly flow distribution are significant, with summer reductions of 40–80% of 1961–90 mean flow, and winter increases of up to 20%. This changing seasonality has a large impact on low flows, with Q95 projected to decrease in magnitude by 40–80% in summer months, with serious consequences for water abstractions and river ecology. In contrast, high flows (> Q5) are projected to increase in magnitude by up to 25%, particularly at high elevation catchments, providing an increased risk of flooding during winter months. These changes will have implications for management of water resources and ecologically important areas under the EU Water Framework Directive.  相似文献   

10.
Aerodynamic Roughness Length of Fresh Snow   总被引：1，自引：1，他引：0  
This study presents the results from a series of wind-tunnel experiments designed to investigate the aerodynamic roughness length z 0 of fresh snow under no-drift conditions. A two-component hot-film anemometer was employed to obtain vertical profiles of velocity statistics in a zero pressure gradient turbulent boundary layer for flow over naturally deposited snow surfaces. The roughness of these snow surfaces was measured by means of digital photography to capture characteristic length scales that can be related to z 0. Our results show that, under aerodynamically rough conditions, the mean value of the roughness length for fresh snow is \({\langle{z}_{0}\rangle= 0.24}\) mm with a standard deviation σ(z 0) = 0.05 mm. In this study, we show that variations in z 0 are associated with variations in the roughness geometry. The roughness measurements suggest that the estimated values of z 0 are consistent with the presence of irregular roughness structures that develop during snowfalls that mimic ballistic deposition processes.  相似文献   

11.
The atmospheric boundary layer (ABL) over a given coastal station is influenced by the presence of mesoscale sea breeze circulation, together with the local and synoptic weather, which directly or indirectly modulate the vertical thickness of ABL (z ABL). Despite its importance in the characterization of lower tropospheric processes and atmospheric modeling studies, a reliable climatology on the temporal evolution of z ABL is not available over the tropics. Here, we investigate the challenges involved in determination of the ABL heights, and discuss an objective method to define the vertical structure of coastal ABL. The study presents a two year morphology on the diurnal evolution of the vertical thickness of sea breeze flow (z SBF) and z ABL in association with the altitudes of lifting condensation level (z LCL) over Thiruvananthapuram (8.5° N, 76.9° E), a representative coastal station on the western coastline of the Indian sub-continent. We make use of about 516 balloon-borne GPS sonde measurements in the present study, which were carried out as part of the tropical tropopause dynamics field experiment under the climate and weather of the sun-earth system (CAWSES)–India program. Results obtained from the present study reveal major differences in the temporal evolution of the ABL features in relation to the strength of sea breeze circulation and monsoonal wind flow during the winter and summer monsoon respectively. The diurnal evolution in z ABL is very prominent in the winter monsoon as against the summer monsoon, which is attributed to the impact of large-scale monsoonal flow over the surface layer meteorology. For a majority of the database, the z LCL altitudes are found to be higher than that of the z ABL, indicating a possible decoupling of the ABL with the low-level clouds.  相似文献   

12.
High temperature accompanied with high humidity may result in unbearable and oppressive weather. In this study, future changes of extreme high temperature and heat stress in mainland China are examined based on daily maximum temperature (Tx) and daily maximum wet-bulb globe temperature (Tw). Tw has integrated the effects of both temperature and humidity. Future climate projections are derived from the bias-corrected climate data of five general circulation models under the Representative Concentration Pathways (RCPs) 2.6 and 8.5 scenarios. Changes of hot days and heat waves in July and August in the future (particularly for 2020–50 and 2070–99), relative to the baseline period (1981–2010), are estimated and analyzed. The results show that the future Tx and Tw of entire China will increase by 1.5–5°C on average around 2085 under different RCPs. Future increases in Tx and Tw exhibit high spatial heterogeneity, ranging from 1.2 to 6°C across different regions and RCPs. By around 2085, the mean duration of heat waves will increase by 5 days per annum under RCP8.5. According to Tx, heat waves will mostly occur in Northwest and Southeast China, whereas based on Tw estimates, heat waves will mostly occur over Southeast China and the mean heat wave duration will be much longer than those from Tx. The total extreme hot days (Tx or Tw > 35°C) will increase by 10–30 days. Southeast China will experience the severest heat stress in the near future as extreme high temperature and heat waves will occur more often in this region, which is particularly true when heat waves are assessed based on Tw. In comparison to those purely temperature-based indices, the index Tw provides a new perspective for heat stress assessment in China.  相似文献   

13.
A new method is proposed to estimate future net basin supplies and lake levels for the Laurentian Great Lakes based on GCM projections of global climate change. The method first dynamically downscales the GCM simulation with a regional climate model, and then bias—corrects the simulated net basin supply in order to be used directly in a river—routing/lake level scheme. This technique addresses two weaknesses in the traditional approach, whereby observed sequences of climate variables are perturbed with fixed ratios or differences derived directly from GCMs in order to run evaporation and runoff models. Specifically, (1) land surface—atmosphere feedback processes are represented, and (2) changes in variability can be analyzed with the new approach. The method is demonstrated with a single, high resolution simulation, where small changes in future mean lake levels for all the upper Great Lakes are found, and an increase in seasonal range—especially for Lake Superior—is indicated. Analysis of a small ensemble of eight lower resolution regional climate model simulations supports these findings. In addition, a direct comparison with the traditional approach based on the same GCM projections used as the driving simulations in this ensemble shows that the new method indicates smaller declines in level for all the upper Great Lakes than has been reported previously based on the traditional method, though median differences are only a few centimetres in each case.  相似文献   

14.
A regional ocean circulation model was used to project Baltic Sea climate at the end of the twenty-first century. A set of four scenario simulations was performed utilizing two global models and two forcing scenarios. To reduce model biases and to spin up future salinity the so-called Δ-change approach was applied. Using a regional coupled atmosphere–ocean model 30-year climatological monthly mean changes of atmospheric surface data and river discharge into the Baltic Sea were calculated from previously conducted time slice experiments. These changes were added to reconstructed atmospheric surface fields and runoff for the period 1903–1998. The total freshwater supply (runoff and net precipitation) is projected to increase between 0 and 21%. Due to increased westerlies in winter the annual mean wind speed will be between 2 and 13% larger compared to present climate. Both changes will cause a reduction of the average salinity of the Baltic Sea between 8 and 50%. Although salinity in the entire Baltic might be significantly lower at the end of the twenty-first century, deep water ventilation will very likely only slightly change. The largest change is projected for the secondary maximum of sea water age within the halocline. Further, the average temperature will increase between 1.9 and 3.2°C. The temperature response to atmospheric changes lags several months. Future annual maximum sea ice extent will decrease between 46 and 77% in accordance to earlier studies. However, in contrast to earlier results in the warmest scenario simulation one ice-free winter out of 96 seasons was found. Although wind speed changes are uniform, extreme sea levels may increase more than the mean sea level. In two out of four projections significant changes of 100-year surge heights were found.  相似文献   

15.
The mechanisms driving changes in dominant plant species are the key for understanding how grassland ecosystems respond to climate change. In this study, we examined plant functional traits (morphological characteristics: plant height, leaf area, and leaf number; biomasses: aboveground, belowground, and total; and growth indices: root-to-shoot ratio, specific leaf area, and leaf mass ratio) of four zonal Stipa species (S. baicalensis, S. bungeana, S. grandis, and S. breviflora) from Inner Mongolian grassland in response to warming (control, +1.5, +2.0, +4.0, and +6.0?), changing precipitation (-30%, -15%, control, +15%, and +30%), and their combined effects via climate control chambers. The results showed that warming and changing precipitation had significant interactive effects, different from the accumulation of single-factor effects, on functional traits of Stipa species. The correlation and sensitivity of different plant functional traits to temperature and precipitation differed. Among the four species, the accumulation and variability of functional traits had greater partial correlation with precipitation than temperature, except for leaf number, leaf area, and specific leaf area, in S. breviflora, S. bungeana, and S. grandis. For S. baicalensis, the accumulation and variability of plant height, aboveground biomass, and root-to-shoot ratio only had significant partial correlation with precipitation. However, the variability of morphological characteristics, biomasses, and some growth indices, was more sensitive to temperature than precipitation in S. bungeana, S. grandis, and S. breviflora—except for aboveground biomass and plant height. These results reveal that precipitation is the key factor determining the growth and changes in plant functional traits in Stipa species, and that temperature mainly influences the quantitative fluctuations of the changes in functional traits.  相似文献   

16.
This research has been carried out for investigation and comparison of the accuracy and reliability of different methods of unit hydrograph estimation, including geomorphologic (GIUH) and geomorphoclimatic (GCIUH) methods as well as methods by Nash (Nash-IUH), Rosso (Rosso-IUH) and the Soil Conservation Service (SCS); the methods simulated the rainfall-runoff process over the Manshad River basin located in central Iran. The first six equivalent rainfall-runoff events were selected, and a hydrograph of outlet runoff was calculated for each event. Compared were peak time, peak discharge, base time, W 50 and W 75 parameters (hydrograph widths at 50% and 75% of peak discharge) and the volume of outlet runoff simulated by the models; then determined was the model that most efficiently estimated the hydrograph of outlet flow. The comparison of calculated and observed hydrographs showed that the Nash model was more efficient in estimating peak discharge, peak time, outlet runoff volume and the shape of direct surface runoff (DSRO) hydrographs, though it could not precisely simulate base time and W 50 and W 75 parameters. The other methods were more accurate in simulating outlet runoff volume of the hydrographs. The Rosso-IUH and SCS models could estimate the base time parameter better than the others. GIUH performance was comparable to the Nash method and was relatively suitable. In spite of these results, the GIUH, GCIUH, Rosso-IUH and SCS models had weak performance for estimating other characteristics of outlet DSRO hydrographs.  相似文献   

17.
A monthly water balance (WB) model was developed for the Yukon River Basin (YRB). The WB model was calibrated using mean monthly values of precipitation and temperature derived from the Precipitation-elevation Regression on Independent Slopes Model (PRISM) data set and by comparing estimated mean monthly runoff with runoff measured at Pilot Station, Alaska. The calibration procedure used the Shuffled Complex Evolution global search. Potential hydrologic effects of climate change were assessed for the YRB by imposing changes in precipitation and temperature derived from selected Inter-governmental Panel for Climate Change (IPCC) climate simulations. Scenarios from five general circulation model (GCM) simulations were used to provide a range of potential changes. Results from the scenarios indicate an increase in annual runoff in the twenty-first century for the YRB with simulated increases in precipitation having the greatest effect on increases in runoff. Simulated increases in temperature were found to alter the timing of snow accumulation and melt.  相似文献   

18.
Based on the property of entropy, a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China, based on daily precipitation data collected at 553 observation stations in China during 1961–2010. Furthermore, changes in the temporal concentration property of summer precipitation in China were investigated. The results indicate that the regions with larger Q values were located in most parts of Northwest China and the north of the Yellow River, where daily precipitation tended to become temporally concentrated during the study period. On the contrary, smaller Q values were found in eastern Tibetan Plateau, southeastern Northwest China, and most parts of Southwest and South China. The most obvious increasing trend of Q index was found in South China and most parts of Southwest China, where precipitation showed a temporal concentration trend. However, a decreasing trend of Q index was found in Northwest China, the Tibetan Plateau, and the north of the Huaihe River. Variations of the Q index and the summer rainfall total during 1961–2010 in China both exhibited an increasing trend, implying larger temporal variability in rainfall attributes. It is illustrated that the summer precipitation in general became more temporally concentrated with more intense rainfall events and wetter days.  相似文献   

19.
Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Kaidu River Basin in the arid region of northwest China were analyzed to investigate changes in annual runoff during the period of 1960–2009. The nonparametric Mann–Kendall test and the Mann–Kendall–Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. Step change point in annual runoff was identified in the basin, which occurred in the year around 1993 dividing the long-term runoff series into a natural period (1960–1993) and a human-induced period (1994–2009). Then, the hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. In 1994–2009, climate variability was the main factor that increased runoff with contribution of 90.5 %, while the increasing percentage due to human activities only accounted for 9.5 %, showing that runoff in the Kaidu River Basin is more sensitive to climate variability than human activities. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management.  相似文献   

20.
Failure to account for non-climatic changes to water systems, such as design and operation, within climate change impact assessments leads to misconceptions because these activities buffer the human built enviroment from bio-physical impacts. Urban drainage in cold regions, which is dominated by snowmelt, is especially vulnerable to climate change and is investigated in this paper within the context of future rehabilitation of the sewer network. The objectives are to illustrate the relative response of urban drainage to changes in both the pipe network and climate and demonstrate the use of response surfaces for climate change studies. An incremental climate scenario approach is used to generate two sensitivity analyses for waste water inflows to the Lycksele waste water treatment plant in north-central Sweden. Air temperature and precipitation data (1984–1993) are altered incrementally between –5 and +15 °C and –10 and +40% respectively. These data are then used to drive a hydrological transformation model to obtain estimates of sewer infiltration from groundwater. The results are presented as winter and spring response surfaces – these are graphical representations of a response matrix where each point relates to a single model run. Climate scenario envelopes which summarise a series of GCM runs (ACACIA; Carter, 2002, pers. comm.) are overlaid to indicate the range of plausible waste water inflows. Estimates of natural multi-decadal variability are also included. The first sensitivity analysis assumes no change to the drainage system while the second simulates sewer renovation in which the system is fully separated and sewer infiltration is reduced. The main conclusions are that innovations in drainage network technology have a greater potential to alter waste water inflows than climate change and that, while the direction of climate change is fairly certain, there is great uncertainty surrounding magnitude of those changes and their impacts.  相似文献   

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