scholarly journals Changes in U.S. East Coast Cyclone Dynamics with Climate Change

2015 ◽  
Vol 28 (2) ◽  
pp. 468-484 ◽  
Author(s):  
Christopher G. Marciano ◽  
Gary M. Lackmann ◽  
Walter A. Robinson

Abstract Previous studies investigating the impacts of climate change on extratropical cyclones have primarily focused on changes in the frequency, intensity, and distribution of these events. Fewer studies have directly investigated changes in the storm-scale dynamics of individual cyclones. Precipitation associated with these events is projected to increase with warming owing to increased atmospheric water vapor content. This presents the potential for enhancement of cyclone intensity through increased lower-tropospheric diabatic potential vorticity generation. This hypothesis is tested using the Weather Research and Forecasting Model to simulate individual wintertime extratropical cyclone events along the United States East Coast in present-day and future thermodynamic environments. Thermodynamic changes derived from an ensemble of GCMs for the IPCC Fourth Assessment Report (AR4) A2 emissions scenario are applied to analyzed initial and lateral boundary conditions of observed strongly developing cyclone events, holding relative humidity constant. The perturbed boundary conditions are then used to drive future simulations of these strongly developing events. Present-to-future changes in the storm-scale dynamics are assessed using Earth-relative and storm-relative compositing. Precipitation increases at a rate slightly less than that dictated by the Clausius–Clapeyron relation with warming. Increases in cyclone intensity are seen in the form of minimum sea level pressure decreases and a strengthened 10-m wind field. Amplification of the low-level jet occurs because of the enhancement of latent heating. Storm-relative potential vorticity diagnostics indicate a strengthening of diabatic potential vorticity near the cyclone center, thus supporting the hypothesis that enhanced latent heat release is responsible for this regional increase in future cyclone intensity.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin H. Strauss ◽  
Philip M. Orton ◽  
Klaus Bittermann ◽  
Maya K. Buchanan ◽  
Daniel M. Gilford ◽  
...  

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.


2020 ◽  
Author(s):  
Parvathi Vallivattathillam ◽  
Zouhair Lachkar ◽  
Marina Levy ◽  
Shafer Smith

<p>The land-locked northern boundary and seasonal high productivity in the Arabian sea (AS) leads to the formation and the maintenance of one of the most intense and thickest open ocean oxygen minimum zones (OMZ) there. Earlier studies based on both observation and model sensitivity experiments have reported that this perennial OMZ is highly sensitive to the strength of the monsoonal circulation and surface heating. Model simulations from the fifth phase of Coupled Model Intercomparison project (CMIP5) indicate significant changes in the Indian monsoonal circulation and the atmospheric heat fluxes under climate change. However, the future projection of AS OMZ under climate change remains largely uncertain and ill-understood. This is mainly due to a poor representation of the AS OMZ in the CMIP5 simulations and an important spread in their future oxygen projections for the region. Here we explore how downscaling CMIP5 global simulations with a high-resolution configuration of the Regional Ocean Modeling System (ROMS) model coupled to a nitrogen-based NPZD ecosystem model can help improving the representation of the AS OMZ and reduce the spread in CMIP5 projections. To this end, we performed a climatological “reference” simulation, i.e., the control simulation, where ROMS is forced with observed atmospheric and lateral boundary conditions, and a set of corresponding downscaled sensitivity experiment where ROMS is forced with atmospheric and lateral boundary conditions derived from global CMIP5 simulations. For the downscaling experiment, we chose two best performing models from the CMIP5 database based on their skill in simulating the present day (historical) climatology. The control simulation has been extensively validated against the observations for its skill in simulating the physical and biogeochemical variables. We explore the sensitivity of the downscaled oxygen distribution and OMZ to the regional model setup by varying the model resolution from 1/3deg to 1/12deg and expanding the model domain from a small AS-limited domain to one encompassing the full Indian Ocean. We show that the downscaled experiments improve the representation of different classes of oxygen (Oxic - O2 > 60mmol/l; Hypoxic - 60mmol/l >= O2 > 4mmol/l; and the Suboxic  - 4 mmol/l > O2 > 0 mmol/l) within the 0-1500m depth range. In particular, the downscaled experiments simulate a much smaller fraction of suboxic waters relative to hypoxic and oxic fractions, in agreement with observations.</p><p> </p>


2019 ◽  
Vol 76 (7) ◽  
pp. 1885-1902 ◽  
Author(s):  
Dominik Büeler ◽  
Stephan Pfahl

Abstract It is still debated how enhanced cloud-condensational latent heating (LH) in a warmer and moister climate may affect the dynamics of extratropical cyclones. In this study, a diagnostic method that explicitly quantifies the contribution of LH to the lower-tropospheric cyclonic potential vorticity (PV) anomaly is used to investigate the effects of stronger LH on the dynamics, intensity, and impacts of cyclones in two conceptually different sets of idealized climate change simulations. A first set of regional surrogate climate change simulations of individual moderate to intense Northern Hemisphere cyclones in a spatially homogeneously 4-K-warmer climate reveals that enhanced LH can largely but not exclusively explain the substantially varying increase in intensity and impacts of most of these cyclones. A second set of idealized aquaplanet GCM simulations demonstrates that the role of enhanced LH becomes multifaceted for large ensembles of cyclones if climate warming is additionally accompanied by changes in the horizontal and vertical temperature structure: cyclone intensity increases with warming due to the continuous increase in LH, reaches a maximum in climates warmer than present day, and decreases beyond a certain warming once the increase of LH is overcompensated by the counteracting reduction in mean available potential energy. Because of their substantially stronger increase in LH, the most intense cyclones reach their maximum intensity in warmer climates than moderately intense cyclones with weaker LH. This suggests that future projections of the extreme tail of the storm tracks might be particularly sensitive to a correct representation of LH.


2010 ◽  
Vol 67 (4) ◽  
pp. 1066-1090 ◽  
Author(s):  
S. B. Trier ◽  
C. A. Davis ◽  
D. A. Ahijevych

Abstract The diurnal cycle of warm-season precipitation in the Rocky Mountains and adjacent Great Plains of the United States is examined using a numerical modeling framework designed to isolate the role of terrain-influenced diurnally varying flows within a quasi-stationary longwave pattern common to active periods of midsummer convection. Simulations are initialized using monthly averaged conditions and contain lateral boundary conditions that vary only with the diurnal cycle. Together these attributes mitigate effects of transient weather disturbances originating upstream of the model domain. After a spinup period, the final 7 days of the 10-day model integration are analyzed and compared with observations. Results indicate that many salient features of the monthly precipitation climatology are reproduced by the model. These include a stationary afternoon precipitation frequency maximum over the Rocky Mountains followed overnight by an eastward-progressing zone of maximum precipitation frequencies confined to a narrow latitudinal corridor in the Great Plains. The similarity to observations despite the monthly averaged initial and lateral boundary conditions suggests that although progressive weather disturbances (e.g., mobile cold fronts and midtropospheric short waves) that originate outside of the region may help enhance and focus precipitation in individual cases, they are not crucial to the general location and diurnal cycle of midsummer precipitation. The roles of persistent daily features such as the nocturnal low-level jet and the thermally induced mountain–plains vertical circulation on both convection and a mesoscale water budget of the central Great Plains (where the heaviest rain occurs) are discussed.


Climate change is a profoundly social and political challenge with many social justice concerns around every corner. A global issue, climate change threatens the well-being, livelihood, and survival of people in communities worldwide. Often, those who have contributed least to climate change are the most likely to suffer from its negative consequences and are often excluded from the policy discussions and decisions that affect their lives. This book pays particular attention to the social dimensions of climate change. It examines closely people’s lived experience, climate-related injustice and inequity, why some groups are more vulnerable than others, and what can be done about it—especially through greater community inclusion in policy change. A highlight of the book is its diversity of rich, community-based examples from throughout the Global South and North. Sacrificial flood zones in urban Argentina, forced relocation of United Houma tribal members in the United States, and gendered water insecurities in Bangladesh and Australia are just some of the in-depth cases included in the book. Throughout, the book asks social and political questions about climate change. Of key importance, it asks what can be done about the unequal consequences of climate change by questioning and transforming social institutions and arrangements—guided by values that prioritize the experience of affected groups and the inclusion of diverse voices and communities in the policy process.


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