Indices for extreme events in projections of anthropogenic climate change (original) (raw)
Related papers
Bulletin of the American Meteorological Society, 2000
Projections of statistical aspects of weather and climate extremes can be derived from climate models representing possible future climate states. Some of the recent models have reproduced results previously reported in the Intergovernmental Panel on Climate Change (IPCC) Second Assessment Report, such as a greater frequency of extreme warm days and lower frequency of extreme cold days associated with a warmer mean climate, a decrease in diurnal temperature range associated with higher nighttime temperatures, increased precipitation intensity, midcontinent summer drying, decreasing daily variability of surface temperature in winter, and increasing variability of northern midlatitude summer surface temperatures. This reconfirmation of previous results gives an increased confidence in the credibility of the models, though agreement among models does not guarantee those changes will occur. New results since the IPCC Second Assessment Report indicate a possible increase of extreme heat stress events in a warmer climate, an increase of cooling degree days and decrease in heating degree days, an increase of precipitation extremes such that there is a decrease in return periods for 20-yr extreme precipitation events, and more detailed analyses of possible changes in 20-yr return values for extreme maximum and minimum temperatures. Additionally, recent studies are now addressing interannual and synoptic time and space scale processes that affect weather and climate extremes, such as tropical cyclones, El Niño effects, and extratropical storms. However, current climate models are not yet in agreement with respect to possible future changes in such features. *This is the third of five papers in the "Understanding Changes in Weather and Climate Extremes" series.
SOLA, 2006
Future changes in extremes indices on precipitation were projected with a 20-km horizontal grid atmospheric general circulation model. At the end of the 21st Century, heavy precipitation was shown to increase enormously in South Asia, the Amazon, and West Africa, while a dry spell was shown to increase in South Africa, south Australia, and the Amazon, suggesting that the risk of water-related disasters will be higher in these regions. In the Asian monsoon region, heavy precipitation increases notably in Bangladesh and in the Yangtze River basin due to the intensified convergence of water vapor flux in summer. In the Amazon, a dry spell greatly increases due to a reduction in the Walker circulation caused by an El Ni no-like change in SST prescribed as boundary condition.
Future extreme precipitation intensities based on historic events
2017
In a warmer climate, it is expected that precipitation intensities will increase, and form a considerable risk of high-impact precipitation extremes. This study applies three methods to transform a historic extreme precipitation event in the Netherlands to a similar event in a future warmer climate, thus compiling a "future weather" scenario. The first method uses an observation-based non-linear relation between the hourly-observed summer precipitation and the antecedent dew-point temperature (the P iT d relation). The second method simulates the same event by using the convective-permitting numerical weather model (NWP) model HARMONIE, for both present-day and future warmer conditions. The third method is similar to the first method, but applies a simple linear delta transformation to the historic data by using indicators from The Royal Netherlands Meteorological Institute (KNMI)'14 climate scenarios. A comparison of the three methods shows comparable intensity changes, ranging from below the Clausius-Clapeyron (CC) scaling to a 3 times CC increase per degree of warming. In the NWP model, the position of the events is somewhat different; due to small wind and convection changes, the intensity changes somewhat differ with time, but the total spatial area covered by heavy precipitation does not change with the temperature increase. The P iT d method is simple and time efficient compared to numerical models. The outcome can be used directly for hydrological and climatological studies and for impact analysis, such as flood-risk assessments.
Sola, 2006
Changes in temperature-based extremes over land due to global warming estimated by a global 20-km-mesh atmospheric model are analyzed using Frich's five extremes indices. At the end of the 21 st Century, under the Intergovernmental Panel on Climate Change (IPCC) SRES A1B scenario, the model projects that the total number of frost days (Fd) decreases by more than 20 days per year and the length of the growing season (GSL) increases by about 14 34 days in northern mid-and high latitudes. The heat wave duration index (HWDI) and the percentage of time with a daily minimum temperature above the presentday 90 th percentile (Tn90) increase worldwide. The intraannual extreme temperature range (ETR) decreases in northern high latitudes, east Asia, and eastern North America by 1.3 3.9°C, but it increases by 1.0°C in the Amazon. The high-resolution simulation reveals that changes in these indices are influenced by regional properties, such as the altitude and distance from the coast.
Geophysical Research Letters, 2013
1] Precipitation extremes are expected to increase in a warming climate; thus, it is essential to characterize their potential future changes. Here we evaluate eight highresolution global climate model simulations in the twentieth century and provide new evidence on projected global precipitation extremes for the 21st century. A significant intensification of daily extremes for all seasons is projected for the middle and high latitudes of both hemispheres at the end of the present century. For the subtropics and tropics, the lack of reliable and consistent estimations found for both the historical and future simulations might be connected with model deficiencies in the representation of organized convective systems. Low intermodel variability and good agreement with high-resolution regional observations are found for the twentieth century winter over the Northern Hemisphere middle and high latitudes. Citation: Toreti, A.,
Journal of Geophysical Research, 2006
An analysis is undertaken of the climate of precipitation extremes as simulated by six European regional climate models (RCMs) in order to describe/quantify future changes and to examine/interpret differences between models. Each model has adopted boundary conditions from the same ensemble of GCM integrations for present and future (2071-2100) climate under the A2 emission scenario. The main diagnostics are multi-year return values of daily precipitation totals, estimated from extreme value analysis. An evaluation of the RCMs against observations in the Alpine region shows that model biases for extremes are comparable to, or even smaller than for wet-day intensity and mean precipitation.
Global trends in extreme precipitation: climate models versus observations
Precipitation events are expected to become substantially more intense under global warming, but few global comparisons of observations and climate model simulations are available to constrain predictions of future changes in precipitation extremes. We present a systematic global-scale comparison of changes in historical annualmaximum daily precipitation between station observations (compiled in HadEX2) and the suite of global climate models contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5). We use both parametric and non-parametric methods to quantify the strength of trends in extreme precipitation in observations and models, taking care to sample them spatially and temporally in comparable ways. We find that both observations and models show generally increasing trends in extreme precipitation since 1901, with the largest changes in the deep tropics. Annual-maximum daily precipitation (Rx1day) has increased faster in the observations than in most of the CMIP5 models. On a global scale, the observational annual-maximum daily precipitation has increased by an average of 5.73 mm over the last 110 years, or 8.5 % in relative terms. This corresponds to an increase of 10 % K −1 in global warming since 1901, which is larger than the average of climate models, with 8.3 % K −1 . The average rate of increase in extreme precipitation per K of warming in both models and observations is higher than the rate of increase in atmospheric water vapor content per K of warming expected from the Clausius-Clapeyron equation. We expect our findings to help inform assessments of precipitationrelated hazards such as flooding, droughts and storms.
Journal of Geophysical Research, 2006
An analysis is undertaken of the climate of precipitation extremes as simulated by six European regional climate models (RCMs) in order to describe/quantify future changes and to examine/interpret differences between models. Each model has adopted boundary conditions from the same ensemble of GCM integrations for present and future (2071-2100) climate under the A2 emission scenario. The main diagnostics are multi-year return values of daily precipitation totals, estimated from extreme value analysis. An evaluation of the RCMs against observations in the Alpine region shows that model biases for extremes are comparable to, or even smaller than for wet-day intensity and mean precipitation.
Future extreme events in European climate: an exploration of regional climate model projections
Climatic Change, 2007
This paper presents an overview of changes in the extreme events that are most likely to affect Europe in forthcoming decades. A variety of diagnostic methods are used to determine how heat waves, heavy precipitation, drought, wind storms, and storm surges change between present (1961-90) and future (2071-2100) climate on the basis of regional climate model simulations produced by the PRUDENCE project. A summary of the main results follows. Heat waves -Regional surface warming causes the frequency, intensity and duration of heat waves to increase over Europe. By the end of the twenty first century, countries in central Europe will experience the same number of hot days as are currently experienced in southern Europe. The intensity of extreme temperatures increases more rapidly than the intensity of more moderate temperatures over the continental interior due to increases in temperature variability. Precipitation -Heavy winter precipitation increases in central and northern Europe and decreases in the south; heavy summer precipitation increases in north-eastern Europe and decreases in the south. Mediterranean droughts start earlier in the year and last longer. Winter storms -Extreme wind speeds increase between 45°N and 55°N, except over and south of the Alps, and become more north-westerly than cuurently. These changes are associated with reductions in mean sea-level pressure, leading to more North Sea storms and a corresponding increase in storm surges along coastal regions of Holland, Germany and Denmark, in particular. These results are found to depend to different degrees on model formulation. While the responses of heat waves are robust to model formulation, the magnitudes of changes in precipitation and wind speed are sensitive to the choice of regional model, and the detailed patterns of these changes are sensitive to the choice of the driving global model. In the case of precipitation, variation between models can exceed both internal variability and variability between different emissions scenarios.
Future extreme precipitation intensities based on a historic event
2018
In a warmer climate, it is expected that precipitation intensities will increase, and form a considerable risk of high-impact precipitation extremes. This study applies three methods to transform a historic extreme precipitation event in the Netherlands to a similar event in a future warmer climate, thus compiling a "future weather" scenario. The first method uses an observation-based non-linear relation between the hourly-observed summer precipitation and the antecedent dew-point temperature (the P iT d relation). The second method simulates the same event by using the convective-permitting numerical weather model (NWP) model HARMONIE, for both present-day and future warmer conditions. The third method is similar to the first method, but applies a simple linear delta transformation to the historic data by using indicators from The Royal Netherlands Meteorological Institute (KNMI)'14 climate scenarios. A comparison of the three methods shows comparable intensity changes, ranging from below the Clausius-Clapeyron (CC) scaling to a 3 times CC increase per degree of warming. In the NWP model, the position of the events is somewhat different ; due to small wind and convection changes, the intensity changes somewhat differ with time, but the total spatial area covered by heavy precipitation does not change with the temperature increase. The P iT d method is simple and time efficient compared to numerical models. The outcome can be used directly for hydrological and climatological studies and for impact analysis, such as flood-risk assessments.