H21E-0870
Global warming impacts on regional hydrology and water resources
The Community Climate System Model version 3 (CCSM3) outputs for temperature, precipitation, land
surface wetness (precipitation less evapotranspiration) and stream flow are analyzed at regional and decadal
scales to determine the plausible impacts of global warming on regional hydrology and water resources.
Precipitation events and stream flow are analyzed to investigate anticipated changes in the intensity, duration
and frequency of extreme events, while land surface wetness is analyzed in conjunction with other variables
to anticipate extreme water-related stresses. In particular, changes in projected global population and water
availability are compared at high space-time precisions to develop hotspots for water scarcity. Uncertainties
in temperature and precipitation are assessed by comparing the CCSM3 model outputs with reanalysis data,
which are in turn based on observations and available from the National Centers for Environmental Prediction
(NCEP). The possibility of developing uncertainty characterizations for projected stream flow is explored.
http://www.ornl.gov/knowledgediscovery/WarGaming
H21E-0871
The Role of Culture in Adaptation and Vulnerability to Climate Change.
AMMA (African Monsoon Multidisciplinary Analyses) aims to improve our ability to forecast weather and climate in the West African region as well as understanding the impacts and adaptive responses of people and environment. While the complexity and unpredictability of the West African monsoon systems provide an intriguing challenge for science, it is potentially devastating for the many West African people affected by it. Across the region from Senegal to Niger people are trying to deal with and negotiate the consequences of this complexity and unpredictability. The objective of the AMMA Word Package 3.2 is to understand and map how they do this and to attempt to single out the importance of climate factors for local land use and livelihood strategies, decision-making and social relations. Researchers from Senegal, Mali, Burkina Faso, Niger, Nigeria and Denmark developed a common questionnaire and interview guide that was implemented at 16 field sites in 5 countries. The sites were selected to represent the region and were located along north- south and east-west transects, and included both agricultural and pastoral locations. Moreover, in depth studies took place in several sites. In one of these, located in Northern Burkina Faso, there was a specific focus on how adaptation to climate change is related to ethnicity and the issue of values and culture in adaptation and vulnerability to climate change was raised. Strategies of two ethnic groups, Rimaiibe and Fulbe, were compared and it was shown that despite their presence in the same physical environment and their shared experience of climate change, the two groups have adapted very different strategies due to cultural values and historical relations. This has had profound impacts on the relations between the two ethnic groups. The former masters, Fulbe, have been much less successful with their strategies than their former slaves, Rimaiibe, and today the latter group is the dominant one within the village. It is concluded that (1) cultural values are significant determinants of adaptation and vulnerability and (2) adaptation strategies and thus climate change might have large social impacts radically altering exiting social relations
H21E-0872
Identification of Non-linear Behavior in Transient Climate Change Projections of Soil Moisture Over the United States
Here we present a methodology for identifying non-linear behavior in the time evolution of climate parameters derived from global and regional climate change predictions. While many climate parameters - such as daily minimum, daily maximum, and mean temperatures - show a quasi-linear response to changes in radiative forcing associated with increasing greenhouse gas concentrations, those of most interest for socio-economic systems - including water availability, extreme events, and human comfort/health indices - can exhibit highly non-linear time evolutions. We have developed a method for using spatio-temporal data from global and regional climate forecasts to identify regions in which significant and systematic long-term non-linear evolutions may be present, even given quasi-linear anthropogenic forcing. As an example, we will use climate-change projections taken from simulations of NCAR's Community Climate System Model 3.0 (CCSM3) to isolate systematic non-linear behavior of soil moisture variations over the United States. More generally, we will show how this methodology can help identify which regional impacts may be avoidable and which may be unavoidable, as well as which impacts may initially be beneficial and at what point they may start to become detrimental. This information can subsequently be used for short-term and long-term mitigation and planning activities in response to global climate change.
H21E-0873
Moving Window vs. Expanding Retrospective Flood Frequency Estimation in a Changing Climate
The Reclamation Dam Safety Program is charged with evaluating risk at over 400 dams in the Western United States. Current federal guidelines of flood estimations are based on the paradigm that a longer record of flood events produces a better estimate for future flood probability. This is the expanding retrospective paradigm that each additional year of flood information is used in the next evaluation of flood frequency estimation. In a changing climate where temperature and precipitation drivers of extreme events may change, the expanding retrospective paradigm may be vulnerable to a more competitive alternative that takes samples of observed floods from a moving window over the most recent period. This project explores the implications of the expanding retrospective approach for four basins in the Western United States. A set of statistically downscaled climate projections that encompass the variability over each basin is run through operational rainfall-runoff models from the National Weather Service. The resultant set of annual maximum as well as 3-, 5-, and 7- day are analyzed for the changes in distributional properties of floods. Monte-Carlo Log-Pearson III flood frequency estimations are made for future periods of 2011 – 2040, 2041-2070, and 2071-2099 under the expanding retrospective analysis and a moving window analysis. The results indicate that for a system with a monotonic moving trajectory of floods that the expanding retrospective consistently does not provide good estimates of the true flood potential despite the fact that the moving window approach has a lower sample size for distributional estimation.
H21E-0874
Impact Assessment of Climate Change on Extreme Rainfall
Regional climate models(RCMs), with a higher resolution (typically 50 km) are constructed for limited areas and run for shorter periods to consider local features such as mountains, which are not well represented in global models. However, RCMs have been rarely used in the climate change impacts on water resources in Korea. Therefore, this study is intended to use a set of climate scenarios derived by RegCM3 RCM (27km), which is operated by KMA(Korea Meteorological Administration). The frequency analysis of rainfall data is an important part of hydrological design procedures. It is used as input to flood models for a wide range of water resources structures to determine design size and risk. With regard to this purpose, a Nonstationary frequency analysis that can consider an exogenous variable as inputs is employed. We use Hierarchical Bayesian Analysis to consider the exogenous factors that can influence on the frequency of extreme floods. The RCM climate change scenarios are considered as potential predictors of flood risk. The parameters of the model are estimated using a Markov Chain Monte Carlo (MCMC) algorithm. Acknowledgements This study was supported by ¢®¡ÆResearches on national water security in preparation for climate change¢®¡¾ of MLTM¢®¡¾.
H21E-0875
Addressing Extremes within the WCRP - GEWEX Framework
For large international coordination programs such as the Global Energy and Water Cycle Experiment (GEWEX) as part of the World Climate Research Programme (WCRP) it is difficult to strike a good balance between enabling as much international involvement as is possible and desirable and the achievability of the objectives. WCRP has decided that "Extremes Research" is one of several areas where it would like to see its efforts strengthened and scientific research pushed forward. The foci that are being selected should be phrased such that they are practical and achievable within a time span of 1 to 3 years. Preferably these foci build upon the expertise from cross WCRP activities and are not restricted to single core project activities. In this presentation an overview will be given of the various activities within GEWEX that are related to extremes and which ones would be most ideal to be addressed as WCRP foci from a GEWEX perspective. The rationale and context of extreme research will be presented as well links to other national and international programs. "Extremes Research" as a topic is attractive since it has a high societal relevance and impact. However, numerous definitions of extremes exist and they are being used in widely varying contexts making it not always clear of what exactly is being addressed. This presentation will give an outlook on what can be expected research wise in the near future based upon the outcomes of the Extremes Workshop organised last June in Vancouver in the context of the Coordinated Energy and water cycle Observations Project (CEOP) as part of GEWEX. In particular it will be shown how these activities, which will only address certain types of extremes, can be linked to adaptation and mitigation efforts taking place in other organisations and by national and international bodies.
H21E-0876
Strengthening Sustainable Water Resources Adaptive Capacity To Climate Change, A Case Study in Taiwan
Climate change refers to the long-term variation, which may exacerbate short-term climate variability and more extreme events, and then may impact on human society and natural environment. Socioeconomic development is dependent on adequate water resources, but climate change may impact on such supply system, including available streamflow, groundwater, irrigation requirement and also impact on the sustainability for regional water alimentation. The purposes of this study are to assess the climate change impacts on regional water supply systems and to propose response strategies strengthening adaptive capacity to achieve sustainable water uses. To simulate the processes of surface water, a physical model, Hydrologiska Byråns Vattenbalansavdelning (HBV) model, is used. A system dynamics approach using a specialized software tool, Vensim, is used to simulate a water supply system of the Danshuei river watershed in Taiwan to analyze the climate impacts on sustainable water resource utilization. In order to understand the improvement of adaptive capacity for all response strategies, adjusting parameters on a system dynamics model and a definition of a sustainable index is necessary to recognize the benefits of every response strategy. To make the adaptive strategies practical, the selection of adaptive strategies according to the governmental plan such as re-allocation of regional water resources and increase of water supply capacity will be discussed in the end. Hopefully, the adaptive capacity will be enhanced to mitigate climate change impacts on water supply system to achieve sustainable water uses.
H21E-0877
Estimation of climate change impacts on river flow and catchment hydrological connectivity incorporating uncertainty from multiple climate models, stochastic downscaling and hydrological model parameterisation error sources
When estimating climate change impacts, there are many sources of uncertainty which must be considered. The main sources of uncertainty arise from the structure and parameterisation of physically based simulation models, downscaling methods, stochastic realisations of future weather time series and the underlying emission scenarios. This work focuses on the uncertainties resulting from the use of multiple climate models and the joint impact of the stochastic realisations of future weather time series from a weather generator, EARWIG, and from parameter estimation uncertainty of a hydrological model, CAS-Hydro. These tools have been applied to the River Rye, Yorkshire. A suite of model parameter sets and weather realisations have been used to project likely changes to the hydrological functioning under climate change. Results are presented on the projected changes in flow duration curves and the potential changes in the hydrological connectivity by overland flow within the catchment. The statistical sensitivity of the impact predictions to these sources of uncertainty and the use of a multi-model ensemble to enable the production of probabilistic estimates of change is assessed. These estimates of potential changes in flow can then be used to inform the adaptation of water resources design and management.
H21E-0878
Predictions of Changes in Precipitation by 2030
Natural variability on decadal and multi-decadal timescales makes an important contribution to changes in the climate in the near future. Until recently, many climate projections did not include information on the current state of the climate, thus not accounting for the exact phase of internal variability which may enhance predictions for the next few decades. We present estimates of changes in precipitation expected by the 2030s, based on predictions with the Met Office Hadley Centre's decadal prediction model (Smith et al, Science 317, 2007), initialised with observed climate states and including anthropogenic influences. Given the importance of variations in rainfall in hydrological processes, these are useful input into adaptation responses.
H21E-0879
Distinguishing from different climate change scenarios under the uncertainty of hydrological and downscaling parameters
Climate change impacts on water resources, which become important issue around the world. The adaptation and impact assessment have been built to deal with the issue. However, uncertainty is around all processes of evaluation, including model parameters, downscaling, outputs of General circulation models (GCMs) and emission scenarios. GCMs are one of the primary instruments for obtaining projection of future global climate change. Indirectly using the outputs of GCM with different emission scenarios is common way to evaluate the impacts on water resources. The purpose of this study is to distinguish from different GCMs¡¦ output and emission scenarios under the uncertainty of parameters of a hydrological model and of a weather generation model. Mote Carlo simulation is used with disturbing the parameters of the hydrological model and the weather generation model. A distinction of probability distribution frequency is to evaluate the difference of stream flow from different GCMs and emissions. The results are shown that the disturbance of the parameters may lead high agreement of stream flow from different GCMs. The trends of the climate change impact were close with the uncertainty. And the parameter of rainfall probability is very sensitive with the results in downscaling. This was an improvement of the weather generation model to link more information of GCMs.
H21E-0880
Analysis of Hydrologic Variability Over the Colorado River Basin Under Changing Climate Conditions
Provisional assumptions of natural flow over the Colorado River Basin indicate average flow between calendar years 2000 and 2008 to be the lowest 9-year average on the observed record. In response to continued severe drought conditions and water consumption, the United States Bureau of Reclamation (Reclamation) implemented the Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Lake Mead. Under these guidelines, Reclamation used the Colorado River Simulation System (CRSS) model and historical streamflow data to indicate the probability of shortage conditions imposed on the Lower Colorado River Basin to be at most 40% over the interim period. For this study, the development of streamflow projections over the Colorado River Basin is investigated using statistically downscaled climate projections from the World Climate Research Programme's Coupled Intercomparison Project phase 3 multi-model dataset and the ensemble streamflow prediction tool from the Colorado Basin River Forecast Center. These streamflow projections derived from assessments of future climate can then be used to force Reclamation's CRSS model to evaluate the impacts of climate change to operation of the Colorado River System.
H21E-0881
Climate Change in Colorado: Developing a Synthesis of the Science to Support Water Resources Management and Adaptation
In 2007 Colorado's Governor Ritter issued a Colorado Climate Action Plan, in response to the risks
associated with climate change and sets a goal to adapt to those climate changes "that cannot be avoided."
The Western Water Assessment, a NOAA funded RISA program, was commissioned to do a synthesis of the
science on climate change aimed at planners, decisionmakers, and policymakers in water in Colorado.
Changes in Colorado's climate and implications for water resources are occurring in a global context. The
objective of the report is to communicate the state of the science regarding the physical aspects of climate
change that are important for evaluating impacts on Colorado's water resources, and to support state efforts
to develop a water adaptation plan. However, the identification of specific climate change impacts on water
resources is beyond the scope of this report. Water managers have a long history of adapting to changing
circumstances, including changes in economies and land use, environmental concerns, and population
growth. Climate change will further affect the decisions made about use of water. However, current water
management practices may not be robust enough to cope with this climate change.
This presentation reports on the process of developing the report and challenges we faced. We developed
the report based on ongoing interactions with the water management community and discussions with them
about their decision processes and needs. A second presentation (see Barsugli et al) presents the synthesis
findings from the report.
We followed the IPCC WG1 model of observations, attribution, and projections. However, many published
studies and datasets include information about Colorado, there are few climate studies that focus only on the
state. Consequently, many important scientific analyses for Colorado have not been done, and Colorado-
specific information is often imbedded in or averaged with studies of the larger Western U.S. We used
findings from peer-reviewed regional studies, and conducted new analyses derived from existing datasets
and model projections, and took advantage of new regional analyses. In addition to the IPCC Fourth
Assessment, we also took advantage of very new Climate Change Science Program Assessments.
Many water managers, although often technically savvy engineers, hydrologists and other professionals, but
are not trained as climate or atmospheric scientists, and seeks to complexity by using Fahrenheit units,
minimizing use of or defining jargon terms, and re-plotting published figures/data for simplicity. The report is
written at a less technical level than the IPCC reports, and some features are intended to raise the level of
climate literacy of our audience about climate and how climate science is done. For example, the report
includes a primer on climate models and theory that situates Colorado in the context of global climate change
and describes how the unique features of the state -- such as the complex topography -- relate to
interpreting and using climate change projections.
This report responds to Colorado state agencies' and water management community needs to
understanding of climate change and is an initial step in establishing Colorado's water-related adaptation
needs. Another impact of this report is as an experiment in climate services for climate change information
and exploring the challenges of communicating the information to diverse decisionmakers.
http://www.cdc.noaa.gov/people/andrea.ray/
H21E-0882
A Web-Based Climate Change Drought Decision Support System (C2D2S2)
Water managers are increasingly recognizing climate change as a significant issue and are requesting detailed information about potential hydrologic impacts suitable for inclusion in planning. For operational forecasts of streamflow, physically-based hydrologic models that can integrate critical parameters from climate change forecasts are required, as they can be used to directly relate altered temperature regimes to changes in snowpack, streamflow timing, and other effects. Available studies, however, are most often academic in nature and have the added limitation of being incompatible with agency specific water management models or the streamflow period of interest. Commissioning of a study focused on a specific system is generally prohibitively expensive for most municipalities and agencies. This study thus focused on the design and development of a prototype web-based Climate Change Drought Decision Support System (C2D2S2) to enable water managers at various operational- and time-scales to rapidly assess the impact of predicted climate change on natural flows at critical nodes along a river network. Results presented here highlight development of the system, specifically determination of the full range of elements required to build and support C2D2S2 including data, methods, tools and infrastructure necessary to power a full system capable of providing widespread and low-cost access to tools that can be used to generate scenarios of future streamflow over the internet. Results also stress the need for close interaction with, and feedback from stakeholders during development. This participation is critical to ensure potential users can use the tool effectively, and that data products are understandable in the context of operational water management decisions.