scholarly journals Canadian RCM Projected Transient Changes to Precipitation Occurrence, Intensity, and Return Level over North America

2015 ◽  
Vol 28 (17) ◽  
pp. 6920-6937 ◽  
Author(s):  
Jonathan Jalbert ◽  
Anne-Catherine Favre ◽  
Claude Bélisle ◽  
Jean-François Angers ◽  
Dominique Paquin
Keyword(s):  
North America ◽  
Climate Model ◽  
Extreme Values ◽  
Regional Climate ◽  
Return Level ◽  
Nonstationary Processes ◽  
Accurate Analysis ◽  
Precipitation Occurrence ◽  
Time Period ◽  
Precipitation Changes

Abstract As a consequence of the increase in atmospheric greenhouse gas concentrations, potential changes in both precipitation occurrence and intensity may lead to several consequences for Earth’s environment. It is therefore relevant to estimate these changes in order to anticipate their consequences. Many studies have been published on precipitation changes based on climate simulations. These studies are almost always based on time slices; precipitation changes are estimated by comparing two 30-yr windows. To this extent, it is commonly assumed that nonstationary processes are not significant for such a 30-yr slice. Thus, it frees the investigator to statistically model nonstationary processes. However, using transient runs instead of time slices surely leads to more accurate analysis since more data are taken into account. Therefore, the aim of the present study was to develop a transient probabilistic model for describing simulated daily precipitation from the Canadian Regional Climate Model (CRCM) in order to investigate precipitation evolution over North America. Changes to both the occurrence and intensity of precipitation are then assessed from a continuous time period. Extreme values are also investigated with the transient run; a new methodology using the models for precipitation occurrence and intensity was developed for achieving nonstationary frequency analysis. The results herein show an increase in both precipitation occurrence and intensity for most parts of Canada while a decrease is expected over Mexico. For the continental United States, a decrease in both occurrence and intensity is expected in summer but an increase is expected in winter.

scholarly journals A new estimator of heat periods for decadal climate predictions – a complex network approach

2016 ◽  
Vol 23 (4) ◽  
pp. 307-317 ◽  
Author(s):  
Michael Weimer ◽  
Sebastian Mieruch ◽  
Gerd Schädler ◽  
Christoph Kottmeier
Keyword(s):  
Climate Model ◽  
Extreme Values ◽  
Regional Climate ◽  
Low Frequency ◽  
Research Field ◽  
Temperature Threshold ◽  
Fixed Temperature ◽  
Correlation Threshold ◽  
Decadal Climate ◽  
Decadal Predictions

Abstract. Regional decadal predictions have emerged in the past few years as a research field with high application potential, especially for extremes like heat and drought periods. However, up to now the prediction skill of decadal hindcasts, as evaluated with standard methods, is moderate and for extreme values even rarely investigated. In this study, we use hindcast data from a regional climate model (CCLM) for eight regions in Europe and quantify the skill of the model alternatively by constructing time-evolving climate networks and use the network correlation threshold (link strength) as a predictor for heat periods. We show that the skill of the network measure to estimate the low-frequency dynamics of heat periods is superior for decadal predictions with respect to the typical approach of using a fixed temperature threshold for estimating the number of heat periods in Europe.

Precipitation projections of the first multi-model ensemble of regional climate simulations at convection permitting scale

2020 ◽  
Author(s):  
Emanuela Pichelli ◽  
Erika Coppola ◽  
Nikolina Ban ◽  
Filippo Giorgi ◽  
Paolo Stocchi ◽  
...  
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Heavy Precipitation ◽  
Precipitation Intensity ◽  
Historical Period ◽  
Model Ensemble ◽  
Climate Simulations ◽  
Local Impacts ◽  
Precipitation Changes ◽  
Impacts Of Climate Change

<p>We present a multi-model ensemble of regional climate model scenario simulations run at scales allowing for explicit treatment of convective processes (2-3km) over historical and end of century time slices, providing an overview of future precipitation changes over the Alpine domain within the convection-permitting CORDEX-FPS initiative. The 12 simulations of the ensemble have been performed by different research groups around Europe. The simulations are compared with high resolution observations to assess the performance over the historical period and the ensemble of 12 to 25 km resolution driving models is used as a benchmark.</p><p>An improvement of the representation of fine scale details of the analyzed fields on a seasonal scale is found, as well as of the onset and peak of the summer diurnal convection. An enhancement of the projected patterns of change and modifications of its sign for the daily precipitation intensity and heavy precipitation over some regions are found with respect to coarse resolution ensemble. A change of the amplitude of the diurnal cycle for precipitation intensity and frequency is also shown, as well also a larger positive change for high to extreme events for daily and hourly precipitation distributions. The results  are challenging and promising for further assessment of the local impacts of climate change.</p>

scholarly journals A Comparative Analysis of the Wind and Wave Climate in the Black Sea Along the Shipping Routes

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 924 ◽  
Author(s):  
Liliana Rusu ◽  
Alina Raileanu ◽  
Florin Onea
Keyword(s):  
Regional Climate Model ◽  
Black Sea ◽  
Climate Model ◽  
Extreme Values ◽  
Regional Climate ◽  
Wave Model ◽  
Wave Climate ◽  
Reanalysis Data ◽  
The Black Sea ◽  
Wind Fields

The aim of the present work is to assess the wind and wave climate in the Black Sea while considering various data sources. A special attention is given to the areas with higher navigation traffic. Thus, the results are analyzed for the sites located close to the main harbors and also along the major trading routes. The wind conditions were evaluated considering two different data sets, the reanalysis data provided by NCEP-CFSR (U.S. National Centers for Environmental Prediction-Climate Forecast System Reanalysis) and the hindcast results given by a Regional Climate Model (RCM) that were retrieved from EURO-CORDEX (European Domain-Coordinated Regional Climate Downscaling Experiment). For the waves, there were considered the results coming from simulations with the SWAN (Simulating Wave Nearshore) model, forced with the above-mentioned two different wind fields. Based on these results, it can be mentioned that the offshore sites seem to show the best correlation between the two datasets for both wind and waves. As regards the nearshore sites, there is a good agreement between the average values of the wind data that are provided by the different datasets, except for the points located in the southern part of the Black Sea. The same trends noticed for the average values remain also valid for the extreme values. Finally, it can be concluded that the results obtained in this study are useful for the evaluation of the wind and wave climate in the Black Sea. Also, they give a more comprehensive picture on how well the wind field provided by the Regional Climate Model, and the wave model forced with this wind, can represent the features of a complex marine environment as the Black Sea is.

scholarly journals Effects of Climate Change on Wind-Driven Heavy-Snowfall Events over Eastern North America

2018 ◽  
Vol 31 (22) ◽  
pp. 9037-9054 ◽  
Author(s):  
Tyler P. Janoski ◽  
Anthony J. Broccoli ◽  
Sarah B. Kapnick ◽  
Nathaniel C. Johnson
Keyword(s):  
North America ◽  
Greenhouse Gas ◽  
Climate Model ◽  
Extreme Values ◽  
Global Climate Model ◽  
High Elevation ◽  
Eastern North America ◽  
Winter Storms ◽  
Extreme Wind ◽  
Wind Events

Eastern North America contains densely populated, highly developed areas, making winter storms with strong winds and high snowfall among the costliest storm types. For this reason, it is important to determine how the frequency of high-impact winter storms, specifically, those combining significant snowfall and winds, will change in this region under increasing greenhouse gas concentrations. This study uses a high-resolution coupled global climate model to simulate the changes in extreme winter conditions from the present climate to a future scenario with doubled CO2 concentrations (2XC). In particular, this study focuses on changes in high-snowfall, extreme-wind (HSEW) events, which are defined as the occurrence of 2-day snowfall and high winds exceeding thresholds based on extreme values from the control simulation, where greenhouse gas concentrations remain fixed. Mean snowfall consistently decreases across the entire region, but extreme snowfall shows a more inconsistent pattern, with some areas experiencing increases in the frequency of extreme-snowfall events. Extreme-wind events show relatively small changes in frequency with 2XC, with the exception of high-elevation areas where there are large decreases in frequency. As a result of combined changes in wind and snowfall, HSEW events decrease in frequency in the 2XC simulation for much of eastern North America. Changes in the number of HSEW events in the 2XC environment are driven mainly by changes in the frequency of extreme-snowfall events, with most of the region experiencing decreases in event frequency, except for certain inland areas at higher latitudes.

Past trends in precipitation and in the ratio of snow to rain in East Greenland

2021 ◽  
Author(s):  
Jorrit van der Schot
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Regional Climate ◽  
Strong Increase ◽  
Near Surface ◽  
East Greenland ◽  
Solid Precipitation ◽  
Time Period ◽  
Weather Observations ◽  
Meteorological Observations

<p>Climate models project a strong increase in Arctic precipitation as well as an increase in the ratio of liquid to solid precipitation for the 21<sup>st</sup> century. While previous studies have explored past trends in precipitation, relatively little is known about the trends in the ratio of liquid to solid precipitation. A regression analysis of the ratio of liquid to solid precipitation in East Greenland will be conducted to better understand if and how precipitation as well as the relative fractions of snow and rain in precipitation have changed in the time period 1958-2019. This will be done in the context of the interdisciplinary project Snow2Rain which focusses on understanding how the transition from snow to rain is influencing quality of life in and around Tasiilaq (Southeast Greenland). Here, in a broader geographical context, a combination of results from the Regional Atmospheric Climate Model (RACMO2.3p2) and meteorological observations from weather stations along the coast of East Greenland between 65° N and 70° N will be used to assess changes in the ratio of liquid to solid precipitation. The station data will serve to cross-check the output from the regional climate model. A simple partitioning scheme based on near-surface temperature will be used. The combination of model data and weather observations can increase our understanding of trends in the relative fraction of precipitation that falls as snow or rain along the data sparse Greenlandic East coast.</p>

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