An Examination of Climate Change on Extreme Heat Events and Climate–Mortality Relationships in Large U.S. Cities

2011 ◽  
Vol 3 (4) ◽  
pp. 281-292 ◽  
Author(s):  
Scott Greene ◽  
Laurence S. Kalkstein ◽  
David M. Mills ◽  
Jason Samenow
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Large Scale ◽  
Circulation Model ◽  
The United States ◽  
Attributable Mortality ◽  
Climate Projections ◽  
Synoptic Classification ◽  
The Impact ◽  
Related Mortality

Abstract This study examines the impact of a changing climate on heat-related mortality in 40 large cities in the United States. A synoptic climatological procedure, the spatial synoptic classification, is used to evaluate present climate–mortality relationships and project how potential climate changes might affect these values. Specifically, the synoptic classification is combined with downscaled future climate projections for the decadal periods of 2020–29, 2045–55, and 2090–99 from a coupled atmospheric–oceanic general circulation model. The results show an increase in excessive heat event (EHE) days and increased heat-attributable mortality across the study cities with the most pronounced increases projected to occur in the Southeast and Northeast. This increase becomes more dramatic toward the end of the twenty-first century as the anticipated impact of climate change intensifies. The health impact associated with different emissions scenarios is also examined. These results suggest that a “business as usual” approach to greenhouse gas emissions mitigation could result in twice as many heat-related deaths by the end of the century than a lower emissions scenario. Finally, a comparison of future estimates of heat-related mortality during EHEs is presented using algorithms developed during two different, although overlapping, time periods, one that includes some recent large-scale significant EHE intervention strategies (1975–2004), and one without (1975–95). The results suggest these public health responses can significantly decrease heat-related mortality.

scholarly journals The impact of precipitation evaporation on the atmospheric aerosol distribution in EC-Earth v3.2.0

2018 ◽  
Vol 11 (4) ◽  
pp. 1443-1465 ◽  
Author(s):  
Marco de Bruine ◽  
Maarten Krol ◽  
Twan van Noije ◽  
Philippe Le Sager ◽  
Thomas Röckmann
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Circulation Model ◽  
Global Climate Models ◽  
Orthogonal Polarization ◽  
Earth Model ◽  
Climate Projections ◽  
Aerosol Distribution ◽  
The Impact

Abstract. The representation of aerosol–cloud interaction in global climate models (GCMs) remains a large source of uncertainty in climate projections. Due to its complexity, precipitation evaporation is either ignored or taken into account in a simplified manner in GCMs. This research explores various ways to treat aerosol resuspension and determines the possible impact of precipitation evaporation and subsequent aerosol resuspension on global aerosol burdens and distribution. The representation of aerosol wet deposition by large-scale precipitation in the EC-Earth model has been improved by utilising additional precipitation-related 3-D fields from the dynamical core, the Integrated Forecasting System (IFS) general circulation model, in the chemistry and aerosol module Tracer Model, version 5 (TM5). A simple approach of scaling aerosol release with evaporated precipitation fraction leads to an increase in the global aerosol burden (+7.8 to +15 % for different aerosol species). However, when taking into account the different sizes and evaporation rate of raindrops following Gong et al. (2006), the release of aerosols is strongly reduced, and the total aerosol burden decreases by −3.0 to −8.5 %. Moreover, inclusion of cloud processing based on observations by Mitra et al. (1992) transforms scavenged small aerosol to coarse particles, which enhances removal by sedimentation and hence leads to a −10 to −11 % lower aerosol burden. Finally, when these two effects are combined, the global aerosol burden decreases by −11 to −19 %. Compared to the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations, aerosol optical depth (AOD) is generally underestimated in most parts of the world in all configurations of the TM5 model and although the representation is now physically more realistic, global AOD shows no large improvements in spatial patterns. Similarly, the agreement of the vertical profile with Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite measurements does not improve significantly. We show, however, that aerosol resuspension has a considerable impact on the modelled aerosol distribution and needs to be taken into account.

Impacts and uncertainties of climate change on streamflow of the Johor River Basin, Malaysia using a CMIP5 General Circulation Model ensemble

2014 ◽  
Vol 5 (4) ◽  
pp. 676-695 ◽  
Author(s):  
Mou Leong Tan ◽  
Darren L. Ficklin ◽  
Ab Latif Ibrahim ◽  
Zulkifli Yusop
Keyword(s):  
Climate Change ◽  
River Basin ◽  
General Circulation ◽  
Swat Model ◽  
Circulation Model ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Efficiency Coefficient ◽  
Monthly Streamflow ◽  
The Impact

The impact of climate change and uncertainty of climate projections from general circulation models (GCMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) on streamflow in the Johor River Basin, Malaysia was assessed. Eighteen GCMs were evaluated, and the six that adequately simulated historical climate were selected for an ensemble of GCMs under three Representative Concentration Pathways (RCPs; 2.6 (low emissions), 4.5 (moderate emissions) and 8.5 (high emissions)) for three future time periods (2020s, 2050s and 2080s) as inputs into the Soil and Water Assessment Tool (SWAT) hydrological model. We also quantified the uncertainties associated with GCM structure, greenhouse gas concentration pathways (RCP 2.6, 4.5 and 8.5), and prescribed increases of global temperature (1–6 °C) through streamflow changes. The SWAT model simulated historical monthly streamflow well, with a Nash–Sutcliffe efficiency coefficient of 0.66 for calibration and 0.62 for validation. Under RCPs 2.6, 4.5, and 8.5, the results indicate that annual precipitation changes of 1.01 to 8.88% and annual temperature of 0.60–3.21 °C will lead to a projected annual streamflow ranging from 0.91 to 12.95% compared to the historical period. The study indicates multiple climate change scenarios are important for a robust hydrological impact assessment.

The impacts of climate change on a Norwegian high-head hydropower system

2013 ◽  
Vol 4 (1) ◽  
pp. 17-37 ◽  
Author(s):  
Haregewoin Haile Chernet ◽  
Knut Alfredsen ◽  
Ånund Killingtveit
Keyword(s):  
Climate Change ◽  
Simulation Model ◽  
General Circulation ◽  
Large Scale ◽  
Hydrological Model ◽  
Circulation Model ◽  
Climate Change Impacts ◽  
Ocean General Circulation Model ◽  
Hydropower System ◽  
The Impact

Hydropower is the most important renewable energy source for electricity in Norway. However, it is the most vulnerable resource to climate change. Despite the importance of hydropower and its vulnerability to climate change, many studies have been mostly concerned with large-scale resources assessment. This study aims to address the climate change impacts on the scale of a single hydropower system in Norway. The impact studies are based on a combination of hydrological model and a hydropower simulation model driven by scenarios from the Atmospheric-Ocean General Circulation Model (AOGCM). These climate scenarios were used for driving the HBV (Hydrologiska Byråns Vattenbalansavdelning) hydrological model to provide inflow scenarios for the hydropower study. The nMAG hydropower simulation model was used to simulate the hydropower system for the control and scenario period and to investigate future changes in power production. In general, the projections indicate an average increase of 11–17% in annual inflow to the system, earlier peaks and a larger increase in spring. The hydropower simulation results show an increase in energy generation of 9–20% under the current reservoir operation strategies.

scholarly journals Meteorological modes of variability for fine particulate matter (PM2.5) air quality in the United States: implications for PM2.5 sensitivity to climate change

2012 ◽  
Vol 12 (6) ◽  
pp. 3131-3145 ◽  
Author(s):  
A. P. K. Tai ◽  
L. J. Mickley ◽  
D. J. Jacob ◽  
E. M. Leibensperger ◽  
L. Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Transport Model ◽  
Circulation Model ◽  
Multiple Linear Regression Model ◽  
The United States ◽  
Chemical Transport Model ◽  
Modes Of Variability ◽  
The Us ◽  
Cyclone Frequency

Abstract. We applied a multiple linear regression model to understand the relationships of PM2.5 with meteorological variables in the contiguous US and from there to infer the sensitivity of PM2.5 to climate change. We used 2004–2008 PM2.5 observations from ~1000 sites (~200 sites for PM2.5 components) and compared to results from the GEOS-Chem chemical transport model (CTM). All data were deseasonalized to focus on synoptic-scale correlations. We find strong positive correlations of PM2.5 components with temperature in most of the US, except for nitrate in the Southeast where the correlation is negative. Relative humidity (RH) is generally positively correlated with sulfate and nitrate but negatively correlated with organic carbon. GEOS-Chem results indicate that most of the correlations of PM2.5 with temperature and RH do not arise from direct dependence but from covariation with synoptic transport. We applied principal component analysis and regression to identify the dominant meteorological modes controlling PM2.5 variability, and show that 20–40% of the observed PM2.5 day-to-day variability can be explained by a single dominant meteorological mode: cold frontal passages in the eastern US and maritime inflow in the West. These and other synoptic transport modes drive most of the overall correlations of PM2.5 with temperature and RH except in the Southeast. We show that interannual variability of PM2.5 in the US Midwest is strongly correlated with cyclone frequency as diagnosed from a spectral-autoregressive analysis of the dominant meteorological mode. An ensemble of five realizations of 1996–2050 climate change with the GISS general circulation model (GCM) using the same climate forcings shows inconsistent trends in cyclone frequency over the Midwest (including in sign), with a likely decrease in cyclone frequency implying an increase in PM2.5. Our results demonstrate the need for multiple GCM realizations (because of climate chaos) when diagnosing the effect of climate change on PM2.5, and suggest that analysis of meteorological modes of variability provides a computationally more affordable approach for this purpose than coupled GCM-CTM studies.

scholarly journals Impact of climate change on sediment yield in the Mekong River basin: a case study of the Nam Ou basin, Lao PDR

2013 ◽  
Vol 17 (1) ◽  
pp. 1-20 ◽  
Author(s):  
B. Shrestha ◽  
M. S. Babel ◽  
S. Maskey ◽  
A. van Griensven ◽  
S. Uhlenbrook ◽  
...  
Keyword(s):  
Climate Change ◽  
Sediment Yield ◽  
General Circulation ◽  
Climate Models ◽  
Greenhouse Gas Emission ◽  
Circulation Model ◽  
Sediment Flux ◽  
Seasonal Temperature ◽  
Impact Of Climate Change ◽  
The Impact

Abstract. This paper evaluates the impact of climate change on sediment yield in the Nam Ou basin located in northern Laos. Future climate (temperature and precipitation) from four general circulation models (GCMs) that are found to perform well in the Mekong region and a regional circulation model (PRECIS) are downscaled using a delta change approach. The Soil and Water Assessment Tool (SWAT) is used to assess future changes in sediment flux attributable to climate change. Results indicate up to 3.0 °C shift in seasonal temperature and 27% (decrease) to 41% (increase) in seasonal precipitation. The largest increase in temperature is observed in the dry season while the largest change in precipitation is observed in the wet season. In general, temperature shows increasing trends but changes in precipitation are not unidirectional and vary depending on the greenhouse gas emission scenarios (GHGES), climate models, prediction period and season. The simulation results show that the changes in annual stream discharges are likely to range from a 17% decrease to 66% increase in the future, which will lead to predicted changes in annual sediment yield ranging from a 27% decrease to about 160% increase. Changes in intra-annual (monthly) discharge as well as sediment yield are even greater (−62 to 105% in discharge and −88 to 243% in sediment yield). A higher discharge and sediment flux are expected during the wet seasons, although the highest relative changes are observed during the dry months. The results indicate high uncertainties in the direction and magnitude of changes of discharge as well as sediment yields due to climate change. As the projected climate change impact on sediment varies remarkably between the different climate models, the uncertainty should be taken into account in both sediment management and climate change adaptation.

scholarly journals Theoretical aspects of the onset of Indian summer monsoon from perturbed orography simulations in a GCM

2006 ◽  
Vol 24 (8) ◽  
pp. 2075-2089 ◽  
Author(s):  
A. Chakraborty ◽  
R. S. Nanjundiah ◽  
J. Srinivasan
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
General Circulation ◽  
Large Scale ◽  
Vertical Motion ◽  
Circulation Model ◽  
Threshold Value ◽  
The Earth ◽  
Static Energy ◽  
The Impact

Abstract. A theory is proposed to determine the onset of the Indian Summer Monsoon (ISM) in an Atmospheric General Circulation Model (AGCM). The onset of ISM is delayed substantially in the absence of global orography. The impact of orography over different parts of the Earth on the onset of ISM has also been investigated using five additional perturbed simulations. The large difference in the date of onset of ISM in these simulations has been explained by a new theory based on the Surface Moist Static Energy (SMSE) and vertical velocity at the mid-troposphere. It is found that onset occurs only after SMSE crosses a threshold value and the large-scale vertical motion in the middle troposphere becomes upward. This study shows that both dynamics and thermodynamics play profound roles in the onset of the monsoon.

scholarly journals Climate Perspectives in the Intra–Americas Seas

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 959
Author(s):  
Ana María Durán-Quesada ◽  
Rogert Sorí ◽  
Paulina Ordoñez ◽  
Luis Gimeno
Keyword(s):  
Climate Change ◽  
Extreme Events ◽  
Large Scale ◽  
Negative Impact ◽  
Current Knowledge ◽  
Regional Climate ◽  
Climate Projections ◽  
Economic Activities ◽  
Weather And Climate ◽  
The Impact

The Intra–Americas Seas region is known for its relevance to air–sea interaction processes, the contrast between large water masses and a relatively small continental area, and the occurrence of extreme events. The differing weather systems and the influence of variability at different spatio–temporal scales is a characteristic feature of the region. The impact of hydro–meteorological extreme events has played a huge importance for regional livelihood, having a mostly negative impact on socioeconomics. The frequency and intensity of heavy rainfall events and droughts are often discussed in terms of their impact on economic activities and access to water. Furthermore, future climate projections suggest that warming scenarios are likely to increase the frequency and intensity of extreme events, which poses a major threat to vulnerable communities. In a region where the economy is largely dependent on agriculture and the population is exposed to the impact of extremes, understanding the climate system is key to informed policymaking and management plans. A wealth of knowledge has been published on regional weather and climate, with a majority of studies focusing on specific components of the system. This study aims to provide an integral overview of regional weather and climate suitable for a wider community. Following the presentation of the general features of the region, a large scale is introduced outlining the main structures that affect regional climate. The most relevant climate features are briefly described, focusing on sea surface temperature, low–level circulation, and rainfall patterns. The impact of climate variability at the intra–seasonal, inter–annual, decadal, and multi–decadal scales is discussed. Climate change is considered in the regional context, based on current knowledge for natural and anthropogenic climate change. The present challenges in regional weather and climate studies have also been included in the concluding sections of this review. The overarching aim of this work is to leverage information that may be transferred efficiently to support decision–making processes and provide a solid foundation on regional weather and climate for professionals from different backgrounds.

scholarly journals Impact of GCM structure uncertainty on hydrological processes in an arid area of China

2017 ◽  
Vol 49 (3) ◽  
pp. 893-907 ◽  
Author(s):  
Gonghuan Fang ◽  
Jing Yang ◽  
Yaning Chen ◽  
Zhi Li ◽  
Philippe De Maeyer
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Assessment Tool ◽  
Circulation Model ◽  
Hydrological Processes ◽  
Future Climate Change ◽  
Management Decision ◽  
Structural Uncertainty ◽  
Rcp Scenarios ◽  
The Impact

Abstract Quantifying the uncertainty sources in assessment of climate change impacts on hydrological processes is helpful for local water management decision-making. This paper investigated the impact of the general circulation model (GCM) structural uncertainty on hydrological processes in the Kaidu River Basin. Outputs of 21 GCMs from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under two representative concentration pathway (RCP) scenarios (i.e., RCP4.5 and RCP8.5), representing future climate change under uncertainty, were first bias-corrected using four precipitation and three temperature methods and then used to force a well-calibrated hydrological model (the Soil and Water Assessment Tool, SWAT) in the study area. Results show that the precipitation will increase by 3.1%–18% and 7.0%–22.5%, the temperature will increase by 2.0 °C–3.3 °C and 4.2 °C–5.5 °C and the streamflow will change by −26% to 3.4% and −38% to −7% under RCP4.5 and RCP8.5, respectively. Timing of snowmelt will shift forward by approximately 1–2 months for both scenarios. Compared to RCPs and bias correction methods, GCM structural uncertainty contributes most to streamflow uncertainty based on the standard deviation method (55.3%) while it is dominant based on the analysis of variance approach (94.1%).

scholarly journals Methane chemistry in a nutshell – The new submodels CH4 (v1.0) and TRSYNC (v1.0) in MESSy (v2.54.0)

2020 ◽  
Author(s):  
Franziska Winterstein ◽  
Patrick Jöckel
Keyword(s):  
Water Vapour ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Hydrological Cycle ◽  
Circulation Model ◽  
Optimization Techniques ◽  
Specific Humidity ◽  
Climate Projections ◽  
Sensitivity Studies ◽  
The Impact

Abstract. Climate projections including chemical feedbacks rely on state-of-the-art chemistry-climate models (CCMs). Of particular importance is the role of methane (CH4) for the budget of stratospheric water vapor (SWV), which has an important climate impact. However, simulations with CCMs are, due to the large number of involved chemical species, computationally demanding, which limits the simulation of sensitivity studies. To allow for sensitivity studies and ensemble simulations with a reduced demand for computational resources, we introduce a simplified approach to simulate the core of methane chemistry in form of the new Modular Earth Submodel System (MESSy) submodel CH4. It involves an atmospheric chemistry mechanism reduced to the sink reactions of CH4 with predefined fields of the hydroxyl radical (OH), excited oxygen (O(1D)), and chlorine (Cl), as well as photolysis and the reaction products limited to water vapour (H2O). This chemical production of H2O is optionally feed back onto the specific humidity (q) of the connected General Circulation Model (GCM), to account for the impact onto SWV and its effect on radiation and stratospheric dynamics. The submodel CH4 is further capable of simulating the four most prevalent CH4 isotopologues for carbon and hydrogen (CH4 and CH3D as well as 12CH4 and 13CH4), respectively. Furthermore, the production of deuterated water vapour (HDO) is, similar to the production of H2O in the CH4 oxidation, optionally feed back to the isotopological hydrological cycle simulated by the submodel H2OISO, using the newly developed auxiliary submodel TRSYNC. Moreover, the simulation of a user defined number of diagnostic CH4 age- and emission classes is possible, which output can be used for offline inverse optimization techniques. The presented approach combines the most important chemical hydrological feedback including the isotopic signatures with the advantages concerning the computational simplicity of a GCM, in comparison to a full featured CCM.

scholarly journals Impact of solar variability on the frequency variability of the Indian summer monsoon

MAUSAM ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 67-82
Author(s):  
J. R. KULKARNI ◽  
M. MUJUMDAR ◽  
S. P. GHARGE ◽  
V. SATYAN ◽  
G. B. PANT
Keyword(s):  
Time Series ◽  
Summer Monsoon ◽  
Solar Irradiance ◽  
General Circulation ◽  
Large Scale ◽  
Monsoon Season ◽  
Circulation Model ◽  
Solar Constant ◽  
Good Correspondence ◽  
The Impact

Earlier investigations into the epochal behavior of fluctuations in All India Summer Monsoon Rainfall (AISMR) have indicated the existence of a Low Frequency Mode (LFM) in the 60-70 years range. One of the probable sources of this variability may be due to changes in solar irradiance. To investigate this, time series of 128-year solar irradiance data from 1871-1998 has been examined. The Wavelet Transform (WT) method is applied to extract the LFM from these time series, which show a very good correspondence. A case study has been carried out to test the sensitivity of AISMR to solar irradiance. The General Circulation Model (GCM) of the Center of Ocean-Land-Atmosphere (COLA) has been integrated in the control run (using the climatological value of solar constant i.e., 1365 Wm-2) and in the enhanced solar constant condition (enhanced by 10 Wm-2) for summer monsoon season of 1986. The study shows that the large scale atmospheric circulation over the Indian region, in the enhanced solar constant scenario is favorable to good monsoon activity. A conceptual model for the impact of solar irradiance on the AISMR at LFM is also suggested.

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