scholarly journals Heat Waves in Florida: Climatology, Trends, and Related Precipitation Events

2019 ◽  
Vol 58 (3) ◽  
pp. 447-466 ◽  
Author(s):  
Shealynn R. Cloutier-Bisbee ◽  
Ajay Raghavendra ◽  
Shawn M. Milrad
Keyword(s):  
Heat Wave ◽  
Large Scale ◽  
Climate Model ◽  
Heat Waves ◽  
Heavy Precipitation ◽  
Daily Maximum ◽  
Recent Climate ◽  
Climate Model Simulations ◽  
Southern Florida ◽  
Precipitation Events

AbstractHeat waves are increasing in frequency, duration, and intensity and are strongly linked to anthropogenic climate change. However, few studies have examined heat waves in Florida, despite an older population and increasingly urbanized land areas that make it particularly susceptible to heat impacts. Heavy precipitation events are also becoming more frequent and intense; recent climate model simulations showed that heavy precipitation in the three days after a Florida heat wave follow these trends, yet the underlying dynamic and thermodynamic mechanisms have not been investigated. In this study, a heat wave climatology and trend analysis are developed from 1950 to 2016 for seven major airports in Florida. Heat waves are defined based on the 95th percentile of daily maximum, minimum, and mean temperatures. Results show that heat waves exhibit statistically significant increases in frequency and duration at most stations, especially for mean and minimum temperature events. Frequency and duration increases are most prominent at Tallahassee, Tampa, Miami, and Key West. Heat waves in northern Florida are characterized by large-scale continental ridging, while heat waves in central and southern Florida are associated with a combination of a continental ridge and a westward extension of the Bermuda–Azores high. Heavy precipitation events that follow a heat wave are characterized by anomalously large ascent and moisture, as well as strong instability. Light precipitation events in northern Florida are characterized by advection of drier air from the continent, while over central and southern Florida, prolonged subsidence is the most important difference between heavy and light events.

scholarly journals Large-scale heavy precipitation and its link to atmospheric circulation in climate model outputs over central Europe 

2021 ◽  
Author(s):  
Romana Beranova ◽  
Jan Kysely
Keyword(s):  
Atmospheric Circulation ◽  
Central Europe ◽  
Large Scale ◽  
Climate Models ◽  
Climate Model ◽  
Heavy Precipitation ◽  
Human Society ◽  
Circulation Types ◽  
Recent Climate ◽  
Precipitation Events

<p>Heavy large-scale precipitation events are associated with large negative impacts on human society, mainly as they may trigger floods and landslides. Therefore, it is important to better understand underlying physical mechanisms leading to extremes and how they are reproduced in climate models.</p><p>The present study evaluates ability of current climate models to reproduce relationships between large-scale heavy precipitation and atmospheric circulation over central Europe. We use an ensemble of 32 regional climate model (RCM) simulations with the 0.11° resolution, taken from the Euro-CORDEX project. The statistics are compared for the recent climate simulations (1951-2005) against observations from the E-OBS gridded data set to identify main drawbacks of the RCMs. The large-scale heavy precipitation events are defined as days with at least 50% of all grid points over the examined area with heavy precipitation (exceeding the 75th or 90th percentile of the distribution of seasonal rainy days). The association with atmospheric circulation types is investigated through circulation types derived from sea level pressure using airflow indices (direction, strength and vorticity). The analysis is carried out separately for summer (JJA) and winter (DJF) season.</p><p>The number of days with large-scale heavy precipitation per season in observations reflects the seasonal precipitation sums (the larger precipitation sum the more days). In winter, the large-scale heavy precipitation is mainly associated with the west, northwest, southwest and cyclonic circulation types while in summer with the cyclonic, north, southwest and undefined types (in the observed data). Some RCM simulations are not able to reproduce the number of days with the large-scale heavy precipitation events and their relationships with circulation, especially in summer.</p>

scholarly journals On the use of composite analyses to form physical hypotheses: An example from heat wave – SST associations

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ghyslaine Boschat ◽  
Ian Simmonds ◽  
Ariaan Purich ◽  
Tim Cowan ◽  
Alexandre Bernardes Pezza
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Heat Waves ◽  
South Indian Ocean ◽  
South Indian ◽  
Sensitivity Tests ◽  
Pattern Correlation ◽  
Southwest Australia ◽  
Climate Model Simulations

Abstract This paper highlights some caveats in using composite analyses to form physical hypotheses on the associations between environmental variables. This is illustrated using a specific example, namely the apparent links between heat waves (HWs) and sea surface temperatures (SSTs). In this case study, a composite analysis is performed to show the large-scale and regional SST conditions observed during summer HWs in Perth, southwest Australia. Composite results initially point to the importance of the subtropical South Indian Ocean, where physically coherent SST dipole anomalies appear to form a necessary condition for HWs to develop across southwest Australia. However, sensitivity tests based on pattern correlation analyses indicate that the vast majority of days when the identified SST pattern appears are overwhelmingly not associated with observed HWs, which suggests that this is definitely not a sufficient condition for HW development. Very similar findings are obtained from the analyses of 15 coupled climate model simulations. The results presented here have pertinent implications and applications for other climate case studies, and highlight the importance of applying comprehensive statistical approaches before making physical inferences on apparent climate associations.

A Comparison of CMIP3 Simulations of Precipitation over North America with Observations: Daily Statistics and Circulation Features Accompanying Extreme Events

2013 ◽  
Vol 26 (10) ◽  
pp. 3209-3230 ◽  
Author(s):  
Anthony M. DeAngelis ◽  
Anthony J. Broccoli ◽  
Steven G. Decker
Keyword(s):  
North America ◽  
Extreme Events ◽  
Extreme Precipitation ◽  
Large Scale ◽  
Climate Model ◽  
Heavy Precipitation ◽  
Convective Precipitation ◽  
Southern Mexico ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract Climate model simulations of daily precipitation statistics from the third phase of the Coupled Model Intercomparison Project (CMIP3) were evaluated against precipitation observations from North America over the period 1979–99. The evaluation revealed that the models underestimate the intensity of heavy and extreme precipitation along the Pacific coast, southeastern United States, and southern Mexico, and these biases are robust among the models. The models also overestimate the intensity of light precipitation events over much of North America, resulting in fairly realistic mean precipitation in many places. In contrast, heavy precipitation is simulated realistically over northern and eastern Canada, as is the seasonal cycle of heavy precipitation over a majority of North America. An evaluation of the simulated atmospheric dynamics and thermodynamics associated with extreme precipitation events was also conducted using the North American Regional Reanalysis (NARR). The models were found to capture the large-scale physical mechanisms that generate extreme precipitation realistically, although they tend to overestimate the strength of the associated atmospheric circulation features. This suggests that climate model deficiencies such as insufficient spatial resolution, inadequate representation of convective precipitation, and overly smoothed topography may be more important for biases in simulated heavy precipitation than errors in the large-scale circulation during extreme events.

scholarly journals How Important is Vegetation Phenology for European Climate and Heat Waves?

2013 ◽  
Vol 26 (24) ◽  
pp. 10077-10100 ◽  
Author(s):  
Ruth Lorenz ◽  
Edouard L. Davin ◽  
David M. Lawrence ◽  
Reto Stöckli ◽  
Sonia I. Seneviratne
Keyword(s):  
Soil Moisture ◽  
Heat Wave ◽  
Climate Model ◽  
Heat Waves ◽  
Daily Maximum ◽  
Vegetation Phenology ◽  
Area Index ◽  
Summer Climate ◽  
European Climate ◽  
The Impact

Abstract It has been hypothesized that vegetation phenology may play an important role for the midlatitude climate. This study investigates the impact of interannual and intraseasonal variations in phenology on European climate using regional climate model simulations. In addition, it assesses the relative importance of interannual variations in vegetation phenology and soil moisture on European summer climate. It is found that drastic phenological changes have a smaller effect on mean summer and spring climate than extreme changes in soil moisture (roughly ¼ of the temperature anomaly induced by soil moisture changes). However, the impact of phenological anomalies during heat waves is found to be more important. Generally, late and weak greening has amplifying effects and early and strong greening has dampening effects on heat waves; however, regional variations are found. The experiments suggest that in the extreme hot 2003 (western and central Europe) and 2007 (southeastern Europe) summers the decrease in leaf area index amplified the heat wave peaks by about 0.5°C for daily maximum temperatures (about half of the effect induced by soil moisture deficit). In contrast to earlier hypotheses, no anomalous early greening in spring 2003 is seen in the phenological dataset employed here. Hence, the results indicate that vegetation feedbacks amplified the 2003 heat wave but were not responsible for its initiation. In conclusion, the results suggest that phenology has a limited effect on European mean summer climate, but its impact can be as important as that induced by soil moisture anomalies in the context of specific extreme events.

scholarly journals Diverse Characteristics of U.S. Summer Heat Waves

2017 ◽  
Vol 30 (19) ◽  
pp. 7827-7845 ◽  
Author(s):  
Bradfield Lyon ◽  
Anthony G. Barnston
Keyword(s):  
Heat Wave ◽  
Land Surface ◽  
Large Scale ◽  
Heat Waves ◽  
Primary Data ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Regional Variations ◽  
Daily Minimum ◽  
Summer Heat

Abstract Heat waves are climate extremes having significant environmental and social impacts. However, there is no universally accepted definition of a heat wave. The major goal of this study is to compare characteristics of continental U.S. warm season (May–September) heat waves defined using four different variables—temperature itself and three variables incorporating atmospheric moisture—all for differing intensity and duration requirements. To normalize across different locations and climates, daily intensity is defined using percentiles computed over the 1979–2013 period. The primary data source is the U.S. Historical Climatological Network (USHCN), with humidity data from the North American Regional Reanalysis (NARR) also tested and utilized. The results indicate that heat waves defined using daily maximum temperatures are more frequent and persistent than when based on minimum temperatures, with substantial regional variations in behavior. For all four temperature variables, heat waves based on daily minimum values have greater spatial coherency than for daily maximum values. Regionally, statistically significant upward trends (1979–2013) in heat wave frequency are identified, largest when based on daily minimum values, across variables. Other notable differences in behavior include a higher frequency of heat waves based on maximum temperature itself than for variables that include humidity, while daily minimum temperatures show greater similarity across all variables in this regard. Overall, the study provides a baseline to compare with results from climate model simulations and projections, for examining differing regional and large-scale circulation patterns associated with U.S. summer heat waves and for examining the role of land surface conditions in modulating regional variations in heat wave behavior.

scholarly journals Twenty-First-Century Changes in U.S. Regional Heavy Precipitation Frequency Based on Resolved Atmospheric Patterns

2017 ◽  
Vol 30 (7) ◽  
pp. 2501-2521 ◽  
Author(s):  
Xiang Gao ◽  
C. Adam Schlosser ◽  
Paul A. O’Gorman ◽  
Erwan Monier ◽  
Dara Entekhabi
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Heavy Precipitation ◽  
First Century ◽  
Specific Humidity ◽  
Atmospheric Conditions ◽  
Precipitation Frequency ◽  
Model Based ◽  
Twenty First Century ◽  
Precipitation Events

Precipitation-gauge observations and atmospheric reanalysis are combined to develop an analogue method for detecting heavy precipitation events based on prevailing large-scale atmospheric conditions. Combinations of atmospheric variables for circulation (geopotential height and wind vector) and moisture (surface specific humidity, column and up to 500-hPa precipitable water) are examined to construct analogue schemes for the winter [December–February (DJF)] of the “Pacific Coast California” (PCCA) region and the summer [June–August (JJA)] of the Midwestern United States (MWST). The detection diagnostics of analogue schemes are calibrated with 1979–2005 and validated with 2006–14 NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA). All analogue schemes are found to significantly improve upon MERRA precipitation in characterizing the occurrence and interannual variations of observed heavy precipitation events in the MWST. When evaluated with the late twentieth-century climate model simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5), all analogue schemes produce model medians of heavy precipitation frequency that are more consistent with observations and have smaller intermodel discrepancies than model-based precipitation. Under the representative concentration pathways (RCP) 4.5 and 8.5 scenarios, the CMIP5-based analogue schemes produce trends in heavy precipitation occurrence through the twenty-first century that are consistent with model-based precipitation, but with smaller intermodel disparity. The median trends in heavy precipitation frequency are positive for DJF over PCCA but are slightly negative for JJA over MWST. Overall, the analyses highlight the potential of the analogue as a powerful diagnostic tool for model deficiencies and its complementarity to an evaluation of heavy precipitation frequency based on model precipitation alone.

scholarly journals Observations and Regional Climate Model Simulations of Heavy Precipitation Events and Seasonal Anomalies: A Comparison

2002 ◽  
Vol 3 (3) ◽  
pp. 322-334 ◽  
Author(s):  
Kenneth E. Kunkel ◽  
Karen Andsager ◽  
Xin-Zhong Liang ◽  
Raymond W. Arritt ◽  
Eugene S. Takle ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Heavy Precipitation ◽  
Model Simulations ◽  
Climate Model Simulations ◽  
Precipitation Events

Trends in Intense Precipitation in the Climate Record

2005 ◽  
Vol 18 (9) ◽  
pp. 1326-1350 ◽  
Author(s):  
Pavel Ya Groisman ◽  
Richard W. Knight ◽  
David R. Easterling ◽  
Thomas R. Karl ◽  
Gabriele C. Hegerl ◽  
...  
Keyword(s):  
Climate Model ◽  
Heavy Precipitation ◽  
The United States ◽  
Small Radius ◽  
Intense Precipitation ◽  
Instrumental Observations ◽  
Climate Model Simulations ◽  
Precipitation Changes ◽  
The Impact ◽  
Precipitation Events

Abstract Observed changes in intense precipitation (e.g., the frequency of very heavy precipitation or the upper 0.3% of daily precipitation events) have been analyzed for over half of the land area of the globe. These changes have been linked to changes in intense precipitation for three transient climate model simulations, all with greenhouse gas concentrations increasing during the twentieth and twenty-first centuries and doubling in the later part of the twenty-first century. It was found that both the empirical evidence from the period of instrumental observations and model projections of a greenhouse-enriched atmosphere indicate an increasing probability of intense precipitation events for many extratropical regions including the United States. Although there can be ambiguity as to the impact of more frequent heavy precipitation events, the thresholds of the definitions of these events were raised here, such that they are likely to be disruptive. Unfortunately, reliable assertions of very heavy and extreme precipitation changes are possible only for regions with dense networks due to the small radius of correlation for many intense precipitation events.

Future changes in heatwaves over Africa at the convection-permitting scale

2021 ◽  
Author(s):  
Cathryn Birch ◽  
Lawrence Jackson ◽  
Declan Finney ◽  
John Marsham ◽  
Rachel Stratton ◽  
...  
Keyword(s):  
Climate Model ◽  
Daily Rainfall ◽  
Shortwave Radiation ◽  
Daily Maximum ◽  
Future Change ◽  
Driving Mechanisms ◽  
The Future ◽  
Convective Scale ◽  
Climate Model Simulations ◽  
The Impact

<p>Mean temperatures and their extremes have increased over Africa since the latter half of the 20th century and this trend is projected to continue, with very frequent, intense and often deadly heatwaves likely to occur very regularly over much of Africa by 2100. It is crucial that we understand the scale of the future increases in extremes and the driving mechanisms. We diagnose daily maximum wet bulb temperature heatwaves, which allows for both the impact of temperature and humidity, both critical for human health and survivability. During wet bulb heatwaves, humidity and cloud cover increase, which limits the surface shortwave radiation flux but increases longwave warming. It is found from observations and ERA5 reanalysis that approximately 30% of wet bulb heatwaves over Africa are associated with daily rainfall accumulations of more than 1 mm/day on the first day of the heatwave. The first ever pan-African convection-permitting climate model simulations of present-day and RCP8.5 future climate are utilised to illustrate the projected future change in heatwaves, their drivers and their sensitivity to the representation of convection. Compared to ERA5, the convection-permitting model better represents the frequency and magnitude of present-day wet bulb heatwaves than a version of the model with more traditional parameterised convection. The future change in heatwave frequency, duration and magnitude is also larger in the convective-scale simulation, suggesting CMIP-style models may underestimate the future change in wet bulb heat extremes over Africa. The main reason for the larger future change appears to be the ability of the model to produce larger anomalies relative to its climatology in precipitation, cloud and the surface energy balance.</p>

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