scholarly journals Atmospheric Dynamics is the Largest Source of Uncertainty in Future Winter European Rainfall

2018 ◽  
Vol 31 (3) ◽  
pp. 963-977 ◽  
Author(s):  
David Fereday ◽  
Robin Chadwick ◽  
Jeff Knight ◽  
Adam A. Scaife
Keyword(s):  
Atmospheric Circulation ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Precipitation Variability ◽  
Atmospheric Dynamics ◽  
Substantial Part ◽  
Projection Data ◽  
Monthly Precipitation ◽  
Precipitation Changes ◽  
Precipitation Trends

Abstract The IPCC Fifth Assessment Report highlighted large uncertainty in European precipitation changes in the coming century. This paper investigates the sources of intermodel differences using CMIP5 model European precipitation data. The contribution of atmospheric circulation to differences in precipitation trends is investigated by applying cluster analysis to daily mean sea level pressure (MSLP) data. The resulting classification is used to reconstruct monthly precipitation time series, thereby isolating the component of precipitation variability directly related to atmospheric circulation. Reconstructed observed precipitation and reconstructions of simulated historical and projection data are well correlated with the original precipitation series, showing that circulation variability accounts for a substantial fraction of European precipitation variability. Removing the reconstructed precipitation from the original precipitation leaves a residual component related to noncirculation effects (and any small remaining circulation effects). Intermodel spread in residual future European precipitation trends is substantially reduced compared to the spread of the original precipitation trends. Uncertainty in future atmospheric circulation accounts for more than half of the intermodel variance in twenty-first-century precipitation trends for winter months for both northern and southern Europe. Furthermore, a substantial part of this variance is related to different forced dynamical responses in different models and is therefore potentially reducible. These results highlight the importance of understanding future changes in atmospheric dynamics in achieving more robust projections of regional climate change. Finally, the possible dynamical mechanisms that may drive the future differences in regional circulation and precipitation are illustrated by examining simulated teleconnections with tropical precipitation.

scholarly journals Continentality and Oceanity in the Mid and High Latitudes of the Northern Hemisphere and Their Links to Atmospheric Circulation

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Edvinas Stonevicius ◽  
Gintautas Stankunavicius ◽  
Egidijus Rimkus
Keyword(s):  
North America ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climatic Conditions ◽  
High Latitudes ◽  
Teleconnection Patterns ◽  
The Pacific ◽  
The Impact

The climate continentality or oceanity is one of the main characteristics of the local climatic conditions, which varies with global and regional climate change. This paper analyzes indexes of continentality and oceanity, as well as their variations in the middle and high latitudes of the Northern Hemisphere in the period 1950–2015. Climatology and changes in continentality and oceanity are examined using Conrad’s Continentality Index (CCI) and Kerner’s Oceanity Index (KOI). The impact of Northern Hemisphere teleconnection patterns on continentality/oceanity conditions was also evaluated. According to CCI, continentality is more significant in Northeast Siberia and lower along the Pacific coast of North America as well as in coastal areas in the northern part of the Atlantic Ocean. However, according to KOI, areas of high continentality do not precisely correspond with those of low oceanity, appearing to the south and west of those identified by CCI. The spatial patterns of changes in continentality thus seem to be different. According to CCI, a statistically significant increase in continentality has only been found in Northeast Siberia. In contrast, in the western part of North America and the majority of Asia, continentality has weakened. According to KOI, the climate has become increasingly continental in Northern Europe and the majority of North America and East Asia. Oceanity has increased in the Canadian Arctic Archipelago and in some parts of the Mediterranean region. Changes in continentality were primarily related to the increased temperature of the coldest month as a consequence of changes in atmospheric circulation: the positive phase of North Atlantic Oscillation (NAO) and East Atlantic (EA) patterns has dominated in winter in recent decades. Trends in oceanity may be connected with the diminishing extent of seasonal sea ice and an associated increase in sea surface temperature.

scholarly journals Storyline approach to the construction of regional climate change information

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190013 ◽  
Author(s):  
Theodore G. Shepherd
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Regional Climate ◽  
Regional Scale ◽  
Regional Climate Change ◽  
Climate Impacts ◽  
Climate Projections ◽  
Ethical Implications ◽  
Climate Change Information ◽  
The Impact

Climate science seeks to make statements of confidence about what has happened, and what will happen (conditional on scenario). The approach is effective for the global, thermodynamic aspects of climate change, but is ineffective when it comes to aspects of climate change related to atmospheric circulation, which are highly uncertain. Yet, atmospheric circulation strongly mediates climate impacts at the regional scale. In this way, the confidence framework, which focuses on avoiding type 1 errors (false alarms), raises the prospect of committing type 2 errors (missed warnings). This has ethical implications. At the regional scale, however, where information on climate change has to be combined with many other factors affecting vulnerability and exposure—most of which are highly uncertain—the societally relevant question is not ‘What will happen?’ but rather ‘What is the impact of particular actions under an uncertain regional climate change?’ This reframing of the question can cut the Gordian knot of regional climate change information, provided one distinguishes between epistemic and aleatoric uncertainties—something that is generally not done in climate projections. It is argued that the storyline approach to climate change—the identification of physically self-consistent, plausible pathways—has the potential to accomplish precisely this.

An Improved Daily Weather Generator for the Assessment of Regional Climate Change Impacts

2021 ◽  
Author(s):  
Mohammad Reza Khazaei ◽  
Mehraveh Hasirchian ◽  
Bagher Zahabiyoun
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Regional Climate ◽  
Low Frequency ◽  
Climate Change Impacts ◽  
Regional Climate Change ◽  
General Circulation Models ◽  
Weather Generator ◽  
Weather Data ◽  
Monthly Precipitation

Abstract Weather Generators (WGs) are one of the major downscaling tools for assessing regional climate change impacts. However, some deficiencies in the performance of WGs have limited their usage. This paper presents a method for correcting the low-frequency variability (LFV) of precipitation in the Improved Weather Generator (IWG) model. The method is based on bias correction in the monthly precipitation distribution of the generated daily series. The performance of the modified model was tested directly by comparing the statistics of generated and observed weather data for 14 stations, and also indirectly by comparing the characteristics of simulated stream-flows of a basin from the simulations run based on generated and observed weather data. The results showed that the method not only corrected the LFV of precipitation but also improved the reproduction of many other statistics. The provided IWG2 model can serve as a useful tool for the downscaling of General Circulation Models (GCMs) scenarios to assess regional climate change impacts, especially hydrological effects.

Regional Extreme Monthly Precipitation Simulated by NARCCAP RCMs

2010 ◽  
Vol 11 (6) ◽  
pp. 1373-1379 ◽  
Author(s):  
William J. Gutowski ◽  
Raymond W. Arritt ◽  
Sho Kawazoe ◽  
David M. Flory ◽  
Eugene S. Takle ◽  
...  
Keyword(s):  
Mississippi River ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Regional Climate Models ◽  
Department Of Energy ◽  
Monthly Precipitation ◽  
The North ◽  
Climate Change Assessment ◽  
Environmental Prediction

Abstract This paper analyzes the ability of the North American Regional Climate Change Assessment Program (NARCCAP) ensemble of regional climate models to simulate extreme monthly precipitation and its supporting circulation for regions of North America, comparing 18 years of simulations driven by the National Centers for Environmental Prediction (NCEP)–Department of Energy (DOE) reanalysis with observations. The analysis focuses on the wettest 10% of months during the cold half of the year (October–March), when it is assumed that resolved synoptic circulation governs precipitation. For a coastal California region where the precipitation is largely topographic, the models individually and collectively replicate well the monthly frequency of extremes, the amount of extreme precipitation, and the 500-hPa circulation anomaly associated with the extremes. The models also replicate very well the statistics of the interannual variability of occurrences of extremes. For an interior region containing the upper Mississippi River basin, where precipitation is more dependent on internally generated storms, the models agree with observations in both monthly frequency and magnitude, although not as closely as for coastal California. In addition, simulated circulation anomalies for extreme months are similar to those in observations. Each region has important seasonally varying precipitation processes that govern the occurrence of extremes in the observations, and the models appear to replicate well those variations.

scholarly journals A Simple Equation for Regional Climate Change and Associated Uncertainty

2008 ◽  
Vol 21 (7) ◽  
pp. 1589-1604 ◽  
Author(s):  
Filippo Giorgi
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Regional Climate ◽  
Regional Climate Change ◽  
First Century ◽  
Temperature And Precipitation ◽  
Regional Temperature ◽  
Global Temperature Change ◽  
Simple Equations ◽  
Precipitation Changes

Abstract Simple equations are developed to express regional climate changes for the twenty-first century and associated uncertainty in terms of the global temperature change (GTC) without a dependence on the underlying emission pathways. The equations are applied to regional temperature and precipitation changes over different regions of the world, and relevant parameters are calculated using the latest multimodel ensemble of global climate change simulations. Examples are also shown of how to use the equations to develop probability density functions (PDFs) of regional climate change based on PDFs of GTC. The main advantage of these equations is that they can be used to estimate regional changes from GTC obtained either from simple and intermediate complexity models or from target CO2 stabilization concentrations.

scholarly journals Statistical Analysis of Recent and Future Rainfall and Temperature Variability in the Mono River Watershed (Benin, Togo)

Climate ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 8 ◽  
Author(s):  
Lawin Emmanuel ◽  
Nina Hounguè ◽  
Chabi Biaou ◽  
Djigbo Badou
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Standardized Precipitation Index ◽  
Baseline Period ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Projection Data ◽  
Monthly Precipitation ◽  
Observation Data ◽  
River Watershed

This paper assessed the current and mid-century trends in rainfall and temperature over the Mono River watershed. It considered observation data for the period 1981–2010 and projection data from the regional climate model (RCM), REMO, for the period 2018–2050 under emission scenarios RCP4.5 and RCP8.5. Rainfall data were interpolated using ordinary kriging. Mann-Kendall, Pettitt and Standardized Normal Homogeneity (SNH) tests were used for trends and break-points detection. Rainfall interannual variability analysis was based on standardized precipitation index (SPI), whereas anomalies indices were considered for temperature. Results revealed that on an annual scale and all over the watershed, temperature and rainfall showed an increasing trend during the observation period. By 2050, both scenarios projected an increase in temperature compared to the baseline period 1981–2010, whereas annual rainfall will be characterized by high variabilities. Rainfall seasonal cycle is expected to change in the watershed: In the south, the second rainfall peak, which usually occurs in September, will be extended to October with a higher value. In the central and northern parts, rainfall regime is projected to be characterized by late onsets, a peak in September and lower precipitation until June and higher thereafter. The highest increase and decrease in monthly precipitation are expected in the northern part of the watershed. Therefore, identifying relevant adaptation strategies is recommended.

scholarly journals Regional Climate Impacts of Future Changes in the Mid–Latitude Atmospheric Circulation: a Storyline View

2019 ◽  
Vol 5 (4) ◽  
pp. 358-371 ◽  
Author(s):  
Giuseppe Zappa
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Cold Season ◽  
Climate Impacts ◽  
Surface Warming ◽  
Circulation Change ◽  
Mean Circulation ◽  
Strong Control

Abstract Purpose of Review Atmospheric circulation exerts a strong control on regional climate and extremes. However, projections of future circulation change remain uncertain, thus affecting the assessment of regional climate change. The purpose of this review is to describe some key cases where regional precipitation and windiness strongly depend on the mid-latitude atmospheric circulation response to warming, and summarise this into alternative plausible storylines of regional climate change. Recent Findings Recent research has enabled to better quantify the importance of dynamical aspects of climate change in shaping regional climate. The cold season precipitation response in Mediterranean-like regions is identified as one of the most susceptible impact-relevant aspects of regional climate driven by mid-latitude circulation changes. A circulation-forced drying might already be emerging in the actual Mediterranean, Chile and southwestern Australia. Increasing evidence indicates that distinct regional changes in atmospheric circulation and European windiness might unfold depending on the interplay of different climate drivers, such as surface warming patterns, sea ice loss and stratospheric changes. Summary The multi-model mean circulation response to warming tends to show washed-out signals due to the lack of robustness in the model projections, with implications for regional changes. To better communicate the information contained within these projections, it is useful to discuss regional climate change conditionally on alternative plausible storylines of atmospheric circulation change. As progress continues in understanding the factors driving the response of circulation to global warming, developing such storylines will provide end–to–end and physically self-consistent descriptions of plausible future unfoldings of regional climate change.

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